Effect of ozone oxidative preconditioning in preventing early radiation-induced lung injury in rats

PubMed Central

Bakkal, B.H.; Gultekin, F.A.; Guven, B.; Turkcu, U.O.; Bektas, S.; Can, M.

2013-01-01

Ionizing radiation causes its biological effects mainly through oxidative damage induced by reactive oxygen species. Previous studies showed that ozone oxidative preconditioning attenuated pathophysiological events mediated by reactive oxygen species. As inhalation of ozone induces lung injury, the aim of this study was to examine whether ozone oxidative preconditioning potentiates or attenuates the effects of irradiation on the lung. Rats were subjected to total body irradiation, with or without treatment with ozone oxidative preconditioning (0.72 mg/kg). Serum proinflammatory cytokine levels, oxidative damage markers, and histopathological analysis were compared at 6 and 72 h after total body irradiation. Irradiation significantly increased lung malondialdehyde levels as an end-product of lipoperoxidation. Irradiation also significantly decreased lung superoxide dismutase activity, which is an indicator of the generation of oxidative stress and an early protective response to oxidative damage. Ozone oxidative preconditioning plus irradiation significantly decreased malondialdehyde levels and increased the activity of superoxide dismutase, which might indicate protection of the lung from radiation-induced lung injury. Serum tumor necrosis factor alpha and interleukin-1 beta levels, which increased significantly following total body irradiation, were decreased with ozone oxidative preconditioning. Moreover, ozone oxidative preconditioning was able to ameliorate radiation-induced lung injury assessed by histopathological evaluation. In conclusion, ozone oxidative preconditioning, repeated low-dose intraperitoneal administration of ozone, did not exacerbate radiation-induced lung injury, and, on the contrary, it provided protection against radiation-induced lung damage. PMID:23969972

Acute Ozone-Induced Pulmonary and Systemic Metabolic ...

EPA Pesticide Factsheets

Acute ozone exposure increases circulating stress hormones and induces metabolic alterations in animals and humans. We hypothesized that the increase of adrenal-derived stress hormones is necessary for both ozone-induced metabolic effects and lung injury. Male Wistar-Kyoto rats underwent adrenal demedullation (DEMED), total bilateral adrenalectomy (ADREX), or sham surgery (SHAM). After a 4 day recovery, rats were exposed to air or ozone (1ppm), 4h/day for 1 or 2 days. Circulating adrenaline levels dropped to nearly zero in DEMED and ADREX rats relative to air-exposed SHAM. Corticosterone levels tended to be low in DEMED rats and dropped to nearly zero in ADREX rats. Adrenalectomy in air-exposed rats caused modest changes in metabolites and lung toxicity parameters. Ozone-induced hyperglycemia and glucose intolerance were markedly attenuated in DEMED rats with nearly complete reversal in ADREX rats. Ozone increased circulating epinephrine and corticosterone in SHAM but not in DEMED or ADREX rats. Free fatty acids (p=0.15) and branched-chain amino acids increased after ozone exposure in SHAM but not in DEMED or ADREX rats. Lung minute volume was not affected by surgery or ozone but ozone-induced labored breathing was less pronounced in ADREX rats. Ozone-induced increases in lung protein leakage and neutrophilic inflammation were markedly reduced in DEMED and ADREX rats (ADREX>DMED). Ozone-mediated decreases in circulating white blood cells in SHAM were not obser

Acute Ozone-Induced Pulmonary and Systemic Metabolic ...

EPA Pesticide Factsheets

Acute ozone exposure increases circulating stress hormones and induces peripheral metabolic alterations in animals and humans. We hypothesized that the increase of adrenal-derived stress hormones is necessary for ozone-induced systemic metabolic effects and lung injury. Male Wistar-Kyoto rats (12 week-old) underwent total bilateral adrenalectomy (ADREX), adrenal demedullation (DEMED) or sham surgery (SHEM). After 4 day recovery, rats were exposed to air or ozone (1ppm), 4h/day for 1 or 2 days. Circulating adrenaline levels dropped to nearly zero in DEMED and ADREX rats relative to air-exposed SHAM. Corticosterone levels tended to be low in DEMED rats and dropped to nearly zero in ADREX rats. Adrenalectomy in air-exposed rats caused modest changes in metabolites and lung toxicity parameters. Ozone-induced hyperglycemia and glucose intolerance were markedly attenuated in DEMED with nearly complete reversal in ADREX rats. Ozone increased circulating epinephrine and corticosterone in SHAM but not in DEMED or ADREX rats. Free fatty acids and branched-chain amino acids tended to increase after ozone exposure in SHAM but not in DEMED or ADREX rats. Lung minute volume was not affected by surgery or ozone but ozone-induced labored breathing was less pronounced in ADREX rats. Ozone-induced increases in lung protein leakage and neutrophilic inflammation were markedly reduced in DEMED and ADREX rats (ADREX>DMED). Ozone-mediated decrease in circulating WBC in SHAM was not

Evaluation of ozone emissions and exposures from consumer products and home appliances.

PubMed

Zhang, Q; Jenkins, P L

2017-03-01

Ground-level ozone can cause serious adverse health effects and environmental impacts. This study measured ozone emissions and impacts on indoor ozone levels and associated exposures from 17 consumer products and home appliances that could emit ozone either intentionally or as a by-product of their functions. Nine products were found to emit measurable ozone, one up to 6230 ppb at a distance of 5 cm (2 inches). One use of these products increased room ozone concentrations by levels up to 106 ppb (mean, from an ozone laundry system) and personal exposure concentrations of the user by 12-424 ppb (mean). Multiple cycles of use of one fruit and vegetable washer increased personal exposure concentrations by an average of 2550 ppb, over 28 times higher than the level of the 1-h California Ambient Air Quality Standard for ozone (0.09 ppm). Ozone emission rates ranged from 1.6 mg/h for a refrigerator air purifier to 15.4 mg/h for a fruit and vegetable washer. The use of some products was estimated to contribute up to 87% of total daily exposures to ozone. The results show that the use of some products may result in potential health impacts. © 2016 The Authors. Indoor Air published by John Wiley & Sons Ltd.

Elevated CO2 and/or ozone modify lignification in the wood of poplars (Populus tremula x alba)

PubMed Central

Richet, Nicolas; Afif, Dany; Tozo, Koffi; Pollet, Brigitte; Maillard, Pascale; Huber, Françoise; Priault, Pierrick; Banvoy, Jacques; Gross, Patrick; Dizengremel, Pierre; Lapierre, Catherine; Perré, Patrick; Cabané, Mireille

2012-01-01

Trees will have to cope with increasing levels of CO2 and ozone in the atmosphere. The purpose of this work was to assess whether the lignification process could be altered in the wood of poplars under elevated CO2 and/or ozone. Young poplars were exposed either to charcoal-filtered air (control), to elevated CO2 (800 μl l−1), to ozone (200 nl l−1) or to a combination of elevated CO2 and ozone in controlled chambers. Lignification was analysed at different levels: biosynthesis pathway activities (enzyme and transcript), lignin content, and capacity to incorporate new assimilates by using 13C labelling. Elevated CO2 and ozone had opposite effects on many parameters (growth, biomass, cambial activity, wood cell wall thickness) except on lignin content which was increased by elevated CO2 and/or ozone. However, this increased lignification was due to different response mechanisms. Under elevated CO2, carbon supply to the stem and effective lignin synthesis were enhanced, leading to increased lignin content, although there was a reduction in the level of some enzyme and transcript involved in the lignin pathway. Ozone treatment induced a reduction in carbon supply and effective lignin synthesis as well as transcripts from all steps of the lignin pathway and some corresponding enzyme activities. However, lignin content was increased under ozone probably due to variations in other major components of the cell wall. Both mechanisms seemed to coexist under combined treatment and resulted in a high increase in lignin content. PMID:22553285

Enhanced near-surface ozone under heatwave conditions in a Mediterranean island.

PubMed

Pyrgou, Andri; Hadjinicolaou, Panos; Santamouris, Mat

2018-06-15

Near-surface ozone is enhanced under particular chemical reactions and physical processes. This study showed the seasonal variation of near-surface ozone in Nicosia, Cyprus and focused in summers when the highest ozone levels were noted using a seven year hourly dataset from 2007 to 2014. The originality of this study is that it examines how ozone levels changed under heatwave conditions (defined as 4 consecutive days with daily maximum temperature over 39 °C) with emphasis on specific air quality and meteorological parameters with respect to non-heatwave summer conditions. The influencing parameters had a medium-strong positive correlation of ozone with temperature, UVA and UVB at daytime which increased by about 35% under heatwave conditions. The analysis of the wind pattern showed a small decrease of wind speed during heatwaves leading to stagnant weather conditions, but also revealed a steady diurnal cycle of wind speed reaching a peak at noon, when the highest ozone levels were noted. The negative correlation of NOx budget with ozone was further increased under heatwave conditions leading to steeper lows of ozone in the morning. In summary, this research encourages further analysis into the persistent weather conditions prevalent during HWs stimulating ozone formation for higher temperatures.

What would have happened to the ozone layer if chlorofluorocarbons (CFCs) had not been regulated?

NASA Astrophysics Data System (ADS)

Oman, L.; Newman, P. A.; Douglass, A. R.; Fleming, E. L.; Frith, S. M.; Hurwitz, M.; Kawa, S. R.; Jackman, C. H.; Krotkov, N. A.; Nash, E. R.; Nielsen, J. E.; Pawson, S.; Stolarski, R. S.; Velders, G. J.

2010-12-01

The Montreal Protocol on Substances that Deplete the Ozone Layer was negotiated in 1987 and by 2010 had been signed by all of the nations of the world. In this presentation we use a fully coupled radiation-chemical-dynamical model to simulate a future world where ozone depletion substances (ODSs) were never regulated. In this “world avoided” simulation, ODS levels increase by 3% per year. From 1980 to 2020 we find that 17% of the globally average column ozone is destroyed, and from 1980 to 2065 67% is destroyed. Severe polar depletions (e.g., the Antarctic ozone hole) become year-round rather than just seasonal. Ozone levels in the tropical lower stratosphere remain constant until about 2053 and then collapse to near zero by 2058 as a result of heterogeneous chemical processes (as currently observed in the Antarctic ozone hole). The tropical cooling that triggers the ozone collapse is caused by an increase of the tropical lower stratospheric upwelling. In response to ozone changes, ultraviolet (UV) radiation increases, tripling the erythemal (sunburn) radiation in the northern summer mid-latitudes by 2065.

Medical ozone increases methotrexate clinical response and improves cellular redox balance in patients with rheumatoid arthritis.

PubMed

León Fernández, Olga Sonia; Viebahn-Haensler, Renate; Cabreja, Gilberto López; Espinosa, Irainis Serrano; Matos, Yanet Hernández; Roche, Liván Delgado; Santos, Beatriz Tamargo; Oru, Gabriel Takon; Polo Vega, Juan Carlos

2016-10-15

Medical ozone reduced inflammation, IL-1β, TNF-α mRNA levels and oxidative stress in PG/PS-induced arthritis in rats. The aim of this study was to investigate the medical ozone effects in patients with rheumatoid arthritis treated with methotrexate and methotrexate+ozone, and to compare between them. A randomized clinical study with 60 patients was performed, who were divided into two groups: one (n=30) treated with methotrexate (MTX), folic acid and Ibuprophen (MTX group) and the second group (n=30) received the same as the MTX group+medical ozone by rectal insufflation of the gas (MTX+ozone group). The clinical response of the patients was evaluated by comparing Disease Activity Score 28 (DAS28), Health Assessment Questionnaire Disability Index (HAQ-DI), Anti-Cyclic Citrullinated (Anti-CCP) levels, reactants of acute phase and biochemical markers of oxidative stress before and after 20 days of treatment. MTX+ozone reduced the activity of the disease while MTX merely showed a tendency to decrease the variables. Reactants of acute phase displayed a similar picture. MTX+ozone reduced Anti-CCP levels as well as increased antioxidant system, and decreased oxidative damage whereas MTX did not change. Glutathione correlated with all clinical variables just after MTX+ozone. MTX+ozone increased the MTX clinical response in patients with rheumatoid arthritis. No side effects were observed. These results suggest that ozone can increase the efficacy of MTX probably because both share common therapeutic targets. Medical ozone treatment is capable of being a complementary therapy in the treatment of rheumatoid arthritis. Copyright © 2016 Elsevier B.V. All rights reserved.

Prediction of micropollutant elimination during ozonation of a hospital wastewater effluent.

PubMed

Lee, Yunho; Kovalova, Lubomira; McArdell, Christa S; von Gunten, Urs

2014-11-01

Determining optimal ozone doses for organic micropollutant elimination during wastewater ozonation is challenged by the presence of a large number of structurally diverse micropollutants for varying wastewater matrice compositions. A chemical kinetics approach based on ozone and hydroxyl radical (·OH) rate constant and measurements of ozone and ·OH exposures is proposed to predict the micropollutant elimination efficiency. To further test and validate the chemical kinetics approach, the elimination efficiency of 25 micropollutants present in a hospital wastewater effluent from a pilot-scale membrane bioreactor (MBR) were determined at pH 7.0 and 8.5 in bench-scale experiments with ozone alone and ozone combined with H2O2 as a function of DOC-normalized specific ozone doses (gO3/gDOC). Furthermore, ozone and ·OH exposures, ·OH yields, and ·OH consumption rates were determined. Consistent eliminations as a function of gO3/gDOC were observed for micropollutants with similar ozone and ·OH rate constants. They could be classified into five groups having characteristic elimination patterns. By increasing the pH from 7.0 to 8.5, the elimination levels increased for the amine-containing micropollutants due to the increased apparent second-order ozone rate constants while decreased for most micropollutants due to the diminished ozone or ·OH exposures. Increased ·OH quenching by effluent organic matter and carbonate with increasing pH was responsible for the lower ·OH exposures. Upon H2O2 addition, the elimination levels of the micropollutants slightly increased at pH 7 (<8%) while decreased considerably at pH 8.5 (up to 31%). The elimination efficiencies of the selected micropollutants could be predicted based on their ozone and ·OH rate constants (predicted or taken from literature) and the determined ozone and ·OH exposures. Reasonable agreements between the measured and predicted elimination levels were found, demonstrating that the proposed chemical kinetics method can be used for a generalized prediction of micropollutant elimination during wastewater ozonation. Out of 67 analyzed micropollutants, 56 were present in the tested hospital wastewater effluent. Two-thirds of the present micropollutants were found to be ozone-reactive and efficiently eliminated at low ozone doses (e.g., >80% for gO3/gDOC = 0.5). Copyright © 2014 Elsevier Ltd. All rights reserved.

Understanding Differences in Upper Stratospheric Ozone Response to Changes in Chlorine and Temperature as Computed Using CCMVal Models

NASA Technical Reports Server (NTRS)

Douglass, A. R.; Stolarski, R. S.; Strahan, S. E.; Oman, L. D.

2012-01-01

Projections of future ozone levels are made using models that couple a general circulation model with a representation of atmospheric photochemical processes, allowing interactions among photochemical processes, radiation, and dynamics. Such models are known as chemistry and climate models (CCMs). Although developed from common principles and subject to the same boundary conditions, simulated ozone time series vary for projections of changes in ozone depleting substances (ODSs) and greenhouse gases. In the upper stratosphere photochemical processes control ozone level, and ozone increases as ODSs decrease and temperature decreases due to greenhouse gas increase. Simulations agree broadly but there are quantitative differences in the sensitivity of ozone to chlorine and to temperature. We obtain insight into these differences in sensitivity by examining the relationship between the upper stratosphere annual cycle of ozone and temperature as produced by a suite of models. All simulations conform to expectation in that ozone is less sensitive to temperature when chlorine levels are highest because chlorine catalyzed loss is nearly independent of temperature. Differences in sensitivity are traced to differences in simulated temperature, ozone and reactive nitrogen when chlorine levels are close to background. This work shows that differences in the importance of specific processes underlie differences in simulated sensitivity of ozone to composition change. This suggests a) the multi-model mean is not a best estimate of the sensitivity of upper ozone to changes in ODSs and temperature; b) the spread of values is not an appropriate measure of uncertainty.

Changes in springtime tropospheric ozone at Mt. Happo from 1998 to 2016, linked to Asian emissions and North Pacific climate

NASA Astrophysics Data System (ADS)

Okamoto, S.; Tanimoto, H.; Hirota, N.; Ikeda, K.; Akimoto, H.

2017-12-01

During the past decades, springtime ozone concentrations in the downwind regions of East Asia have rapidly increased with the increase of anthropogenic emissions. However, recent several studies based on the analysis of satellite tropospheric nitrogen dioxides data inferred possible peaking out of nitrogen oxides emissions in China. In addition to the precursor emissions, climate plays an important role in controlling the variations and distributions of tropospheric ozone. Here we revisited and updated the long-term trend of tropospheric ozone at Mt. Happo, Japan, for the period from 1998 to 2016. Since 1998 the springtime ozone concentration has shown a large increase until 2007, very likely caused by the increase in the emissions of ozone precursors associated with economic growth in eastern China, as evidenced from satellite observations of nitrogen dioxides. After the monotonic increase until 2007, the ozone level has been flattened associated with substantial drop in 2008. Recent low ozone levels were largely influenced by the decrease of the anthropogenic emissions from eastern China. We also found that the efficiency of long-range transport from central eastern China, driven by North Pacific climate, play a role in modulating the year-to-year variations of ozone at Mt. Happo.

Influence of local meteorology and NO2 conditions on ground-level ozone concentrations in the eastern part of Texas, USA.

PubMed

Gorai, A K; Tuluri, F; Tchounwou, P B; Ambinakudige, S

2015-02-01

The influence of local climatic factors on ground-level ozone concentrations is an area of increasing interest to air quality management in regards to future climate change. This study presents an analysis on the role of temperature, wind speed, wind direction, and NO 2 level on ground-level ozone concentrations over the region of Eastern Texas, USA. Ozone concentrations at the ground level depend on the formation and dispersion processes. Formation process mainly depends on the precursor sources, whereas, the dispersion of ozone depends on meteorological factors. Study results showed that the spatial mean of ground-level ozone concentrations was highly dependent on the spatial mean of NO 2 concentrations. However, spatial distributions of NO 2 and ozone concentrations were not uniformed throughout the study period due to uneven wind speeds and wind directions. Wind speed and wind direction also played a significant role in the dispersion of ozone. Temperature profile in the area rarely had any effects on the ozone concentrations due to low spatial variations.

Influence of local meteorology and NO2 conditions on ground-level ozone concentrations in the eastern part of Texas, USA

PubMed Central

Gorai, A. K.; Tuluri, F.; Tchounwou, P. B.; Ambinakudige, S.

2014-01-01

The influence of local climatic factors on ground-level ozone concentrations is an area of increasing interest to air quality management in regards to future climate change. This study presents an analysis on the role of temperature, wind speed, wind direction, and NO2 level on ground-level ozone concentrations over the region of Eastern Texas, USA. Ozone concentrations at the ground level depend on the formation and dispersion processes. Formation process mainly depends on the precursor sources, whereas, the dispersion of ozone depends on meteorological factors. Study results showed that the spatial mean of ground-level ozone concentrations was highly dependent on the spatial mean of NO2 concentrations. However, spatial distributions of NO2 and ozone concentrations were not uniformed throughout the study period due to uneven wind speeds and wind directions. Wind speed and wind direction also played a significant role in the dispersion of ozone. Temperature profile in the area rarely had any effects on the ozone concentrations due to low spatial variations. PMID:25755687

Association of short-term exposure to ground-level ozone and respiratory outpatient clinic visits in a rural location – Sublette County, Wyoming, 2008–2011

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pride, Kerry R., E-mail: hgp3@cdc.gov; Wyoming Department of Health, 6101 Yellowstone Road, Suite 510, Cheyenne, WY 82002; Peel, Jennifer L.

Objective: Short-term exposure to ground-level ozone has been linked to adverse respiratory and other health effects; previous studies typically have focused on summer ground-level ozone in urban areas. During 2008–2011, Sublette County, Wyoming (population: ~10,000 persons), experienced periods of elevated ground-level ozone concentrations during the winter. This study sought to evaluate the association of daily ground-level ozone concentrations and health clinic visits for respiratory disease in this rural county. Methods: Clinic visits for respiratory disease were ascertained from electronic billing records of the two clinics in Sublette County for January 1, 2008–December 31, 2011. A time-stratified case-crossover design, adjusted formore » temperature and humidity, was used to investigate associations between ground-level ozone concentrations measured at one station and clinic visits for a respiratory health concern by using an unconstrained distributed lag of 0–3 days and single-day lags of 0 day, 1 day, 2 days, and 3 days. Results: The data set included 12,742 case-days and 43,285 selected control-days. The mean ground-level ozone observed was 47±8 ppb. The unconstrained distributed lag of 0–3 days was consistent with a null association (adjusted odds ratio [aOR]: 1.001; 95% confidence interval [CI]: 0.990–1.012); results for lags 0, 2, and 3 days were consistent with the null. However, the results for lag 1 were indicative of a positive association; for every 10-ppb increase in the 8-h maximum average ground-level ozone, a 3.0% increase in respiratory clinic visits the following day was observed (aOR: 1.031; 95% CI: 0.994–1.069). Season modified the adverse respiratory effects: ground-level ozone was significantly associated with respiratory clinic visits during the winter months. The patterns of results from all sensitivity analyzes were consistent with the a priori model. Conclusions: The results demonstrate an association of increasing ground-level ozone with an increase in clinic visits for adverse respiratory-related effects in the following day (lag day 1) in Sublette County; the magnitude was strongest during the winter months; this association during the winter months in a rural location warrants further investigation. - Highlights: • We assessed elevated ground-level ozone in frontier Sublette County, Wyoming. • Ground-level ozone concentrations were moderately to highly correlated between stations. • Adverse respiratory-related clinic visits occurred year round at lag 1. • Strongest association of clinic visits was in the coldest months at lag 1.« less

Effects of stratospheric ozone recovery on photochemistry and ozone air quality in the troposphere

NASA Astrophysics Data System (ADS)

Zhang, H.; Wu, S.; Huang, Y.; Wang, Y.

2014-04-01

There has been significant stratospheric ozone depletion since the late 1970s due to ozone-depleting substances (ODSs). With the implementation of the Montreal Protocol and its amendments and adjustments, stratospheric ozone is expected to recover towards its pre-1980 level in the coming decades. In this study, we examine the implications of stratospheric ozone recovery for the tropospheric chemistry and ozone air quality with a global chemical transport model (GEOS-Chem). With a full recovery of the stratospheric ozone, the projected increases in ozone column range from 1% over the low latitudes to more than 10% over the polar regions. The sensitivity factor of troposphere ozone photolysis rate, defined as the percentage changes in surface ozone photolysis rate for 1% increase in stratospheric ozone column, shows significant seasonal variation but is always negative with absolute value larger than one. The expected stratospheric ozone recovery is found to affect the tropospheric ozone destruction rates much more than the ozone production rates. Significant decreases in surface ozone photolysis rates due to stratospheric ozone recovery are simulated. The global average tropospheric OH decreases by 1.7%, and the global average lifetime of tropospheric ozone increases by 1.5%. The perturbations to tropospheric ozone and surface ozone show large seasonal and spatial variations. General increases in surface ozone are calculated for each season, with increases by up to 0.8 ppbv in the remote areas. Increases in ozone lifetime by up to 13% are found in the troposphere. The increased lifetimes of tropospheric ozone in response to stratospheric ozone recovery enhance the intercontinental transport of ozone and global pollution, in particular for the summertime. The global background ozone attributable to Asian emissions is calculated to increase by up to 15% or 0.3 ppbv in the Northern Hemisphere in response to the projected stratospheric ozone recovery.

Interleukin(IL)-1 Regulates Ozone-enhanced Tracheal Smooth Muscle Responsiveness by Increasing Substance P (SP) Production in Intrinsic Airway Neurons of Ferret

PubMed Central

Wu, Z.-X.; Barker, J. S.; Batchelor, T. P.; Dey, R.D.

2008-01-01

Exposure to ozone induces airway hyperresponsiveness (AHR) mediated partly by SP released from nerve terminals of intrinsic airway neurons. Our recent studies showed that IL-1, an important multifunctional proinflammatory cytokine, increases synthesis and release of SP from intrinsic airway neurons. The purpose of this study is to investigate the possible involvement of endogenous IL-1 in modulating neural responses associated with ozone-enhanced airway responsiveness. Ferrets were exposed to 2 ppm ozone or filtered air for 3 hrs. IL-1 in the bronchoalveolar lavage (BAL) fluid was significantly increased in ozone-exposed animals and responses of tracheal smooth muscle to methacholine (MCh) and electrical field stimulation (EFS) were elevated significantly. Both the SP nerve fiber density in tracheal smooth muscle and the number of SP-containing neurons in airway ganglia were significantly increased following ozone exposure. Pretreatment with IL-1 receptor antagonist (IL-1 Ra) significantly diminished ozone-enhanced airway responses to EFS as well as ozone-increased SP in the airway. To selectively investigate intrinsic airway neurons, segments of ferret trachea were maintained in culture conditions for 24 hrs to eliminate extrinsic contributions from sensory nerves. The segments were then exposed to 2 ppm ozone in vitro for 3 hrs. The changes of ozone-induced airway responses to MCh and EFS, and the SP levels in airway neurons paralleled those observed with in vivo ozone exposure. The ozone-enhanced airway responses and neuronal SP levels were inhibited by pretreatment with IL-1 Ra. These findings show that IL-1 is released during ozone exposure enhances airway responsiveness by modulating SP expression in airway neurons. PMID:18718561

Ozone risk for crops and pastures in present and future climates

NASA Astrophysics Data System (ADS)

Fuhrer, Jürg

2009-02-01

Ozone is the most important regional-scale air pollutant causing risks for vegetation and human health in many parts of the world. Ozone impacts on yield and quality of crops and pastures depend on precursor emissions, atmospheric transport and leaf uptake and on the plant’s biochemical defence capacity, all of which are influenced by changing climatic conditions, increasing atmospheric CO2 and altered emission patterns. In this article, recent findings about ozone effects under current conditions and trends in regional ozone levels and in climatic factors affecting the plant’s sensitivity to ozone are reviewed in order to assess implications of these developments for future regional ozone risks. Based on pessimistic IPCC emission scenarios for many cropland regions elevated mean ozone levels in surface air are projected for 2050 and beyond as a result of both increasing emissions and positive effects of climate change on ozone formation and higher cumulative ozone exposure during an extended growing season resulting from increasing length and frequency of ozone episodes. At the same time, crop sensitivity may decline in areas where warming is accompanied by drying, such as southern and central Europe, in contrast to areas at higher latitudes where rapid warming is projected to occur in the absence of declining air and soil moisture. In regions with rapid industrialisation and population growth and with little regulatory action, ozone risks are projected to increase most dramatically, thus causing negative impacts major staple crops such as rice and wheat and, consequently, on food security. Crop improvement may be a way to increase crop cross-tolerance to co-occurring stresses from heat, drought and ozone. However, the review reveals that besides uncertainties in climate projections, parameters in models for ozone risk assessment are also uncertain and model improvements are necessary to better define specific targets for crop improvements, to identify regions most at risk from ozone in a future climate and to set robust effect-based ozone standards.

Ozone perturbations by enhanced levels of CFCs, N2O, and CH4 A two-dimensional diabatic circulation study including uncertainty estimates

NASA Technical Reports Server (NTRS)

Isaksen, I. S. A.; Stordal, F.

1986-01-01

Observations made over the last few years suggest that the tropospheric concentrations of N2O, CH4, and O3 are increasing. Increases in the concentration of chlorofluorocarbons (CFCs) have been observed for some time. The present study is concerned with combined scenarios of future releases of N2O, CH4, and CFCs, which can affect the height profiles of ozone, while changes in latitudinal gradients of ozone may also be expected. Ozone perturbation calculations performed in the two-dimensional transport-chemistry model described by Stordal et al. (1985) are also presented, and the effects of increased levels of CFCs, N2O, and CH4 are examined. It is found that CH4 may be the most important ozone-perturbing trace species in connection with future tropospheric climatic impacts. A substantial increase in the tropospheric abundancy of CH4 could lead to large future ozone enhancements throughout the troposphere and lower stratosphere at middle and low latitudes.

Effects of Ozone Oxidative Preconditioning on TNF-α Release and Antioxidant-Prooxidant Intracellular Balance in Mice During Endotoxic Shock

PubMed Central

Zamora, Zullyt B.; Borrego, Aluet; López, Orlay Y.; Delgado, René; González, Ricardo; Menéndez, Silvia; Hernández, Frank; Schulz, Siegfried

2005-01-01

Ozone oxidative preconditioning is a prophylactic approach, which favors the antioxidant-prooxidant balance for preservation of cell redox state by the increase of antioxidant endogenous systems in both in vivo and in vitro experimental models. Our aim is to analyze the effect of ozone oxidative preconditioning on serum TNF-α levels and as a modulator of oxidative stress on hepatic tissue in endotoxic shock model (mice treated with lipopolysaccharide (LPS)). Ozone/oxygen gaseous mixture which was administered intraperitoneally (0.2, 0.4, and 1.2 mg/kg) once daily for five days before LPS (0.1 mg/kg, intraperitoneal). TNF-α was measured by cytotoxicity on L-929 cells. Biochemical parameters such as thiobarbituric acid reactive substances (TBARS), enzymatic activity of catalase, glutathione peroxidase, and glutathione-S transferase were measured in hepatic tissue. One hour after LPS injection there was a significant increase in TNF-α levels in mouse serum. Ozone/oxygen gaseous mixture reduced serum TNF-α levels in a dose-dependent manner. Statistically significant decreases in TNF-α levels after LPS injection were observed in mice pretreated with ozone intraperitoneal applications at 0.2 (78%), 0.4 (98%), and 1.2 (99%). Also a significant increase in TBARS content was observed in the hepatic tissue of LPS-treated mice, whereas enzymatic activity of glutathion-S transferase and glutathione peroxidase was decreased. However in ozone-treated animals a significant decrease in TBARS content was appreciated as well as an increase in the activity of antioxidant enzymes. These results indicate that ozone oxidative preconditioning exerts inhibitory effects on TNF-α production and on the other hand it exerts influence on the antioxidant-prooxidant balance for preservation of cell redox state by the increase of endogenous antioxidant systems. PMID:15770062

Temperature, ozone, and mortality in urban and non-urban counties in the northeastern United States.

PubMed

Madrigano, Jaime; Jack, Darby; Anderson, G Brooke; Bell, Michelle L; Kinney, Patrick L

2015-01-07

Most health effects studies of ozone and temperature have been performed in urban areas, due to the available monitoring data. We used observed and interpolated data to examine temperature, ozone, and mortality in 91 urban and non-urban counties. Ozone measurements were extracted from the Environmental Protection Agency's Air Quality System. Meteorological data were supplied by the National Center for Atmospheric Research. Observed data were spatially interpolated to county centroids. Daily internal-cause mortality counts were obtained from the National Center for Health Statistics (1988-1999). A two-stage Bayesian hierarchical model was used to estimate each county's increase in mortality risk from temperature and ozone. We examined county-level associations according to population density and compared urban (≥1,000 persons/mile(2)) to non-urban (<1,000 persons/mile(2)) counties. Finally, we examined county-level characteristics that could explain variation in associations by county. A 10 ppb increase in ozone was associated with a 0.45% increase in mortality (95% PI: 0.08, 0.83) in urban counties, while this same increase in ozone was associated with a 0.73% increase (95% PI: 0.19, 1.26) in non-urban counties. An increase in temperature from 70°F to 90°F (21.2°C 32.2°C) was associated with a 8.88% increase in mortality (95% PI: 7.38, 10.41) in urban counties and a 8.08% increase (95% PI: 6.16, 10.05) in non-urban counties. County characteristics, such as population density, percentage of families living in poverty, and percentage of elderly residents, partially explained the variation in county-level associations. While most prior studies of ozone and temperature have been performed in urban areas, the impacts in non-urban areas are significant, and, for ozone, potentially greater. The health risks of increasing temperature and air pollution brought on by climate change are not limited to urban areas.

The study of ozone variations in the Las Vegas metropolitan area using remote sensing information and ground observations

USGS Publications Warehouse

Xian, G.; Crane, M.

2006-01-01

Urban development in the Las Vegas Valley, Nevada, has grown rapidly in the past fifty years. Associated with this growth has been a change in landscape from natural cover types to developed urban land mixed with planned vegetation canopy throughout in the metropolitan area. Air quality in the Las Vegas Valley has been affected by increases in anthropogenic emissions and concentrations of carbon monoxide, ozone, and criteria pollutants of particular matter. Ozone concentration in the region is generally influenced by synoptic and mesoscale meteorological conditions, as well as regional transport of pollutants from the western side of Las Vegas. Local influences from ground-level nitrogen oxide emissions and vegetation canopy coverage also affect ozone concentration. Multi-year observational data collected by a network of local air monitoring stations in Clark County, Nevada, indicate that ozone maximums develop in May and June, while minimums exist primarily from November to February. Ozone concentrations are high on the west and northwest sides of the valley. A nighttime ozone reduction in the urban area characterizes the heterogeneous features of spatial distribution for average ozone levels in the Las Vegas urban area. The urban vegetation canopy has a locally positive effect by reducing ozone in urban areas. Decreased ozone levels associated with increased urban development density suggests that the highest ozone concentrations are associated with medium- to low-density urban development in Las Vegas.

Acute effect of ozone exposure on daily mortality in seven cities of Jiangsu Province, China: No clear evidence for threshold.

PubMed

Chen, Kai; Zhou, Lian; Chen, Xiaodong; Bi, Jun; Kinney, Patrick L

2017-05-01

Few multicity studies have addressed the health effects of ozone in China due to the scarcity of ozone monitoring data. A critical scientific and policy-relevant question is whether a threshold exists in the ozone-mortality relationship. Using a generalized additive model and a univariate random-effects meta-analysis, this research evaluated the relationship between short-term ozone exposure and daily total mortality in seven cities of Jiangsu Province, China during 2013-2014. Spline, subset, and threshold models were applied to further evaluate whether a safe threshold level exists. This study found strong evidence that short-term ozone exposure is significantly associated with premature total mortality. A 10μg/m 3 increase in the average of the current and previous days' maximum 8-h average ozone concentration was associated with a 0.55% (95% posterior interval: 0.34%, 0.76%) increase of total mortality. This finding is robust when considering the confounding effect of PM 2.5 , PM 10 , NO 2 , and SO 2 . No consistent evidence was found for a threshold in the ozone-mortality concentration-response relationship down to concentrations well below the current Chinese Ambient Air Quality Standard (CAAQS) level 2 standard (160μg/m 3 ). Our findings suggest that ozone concentrations below the current CAAQS level 2 standard could still induce increased mortality risks in Jiangsu Province, China. Continuous air pollution control measures could yield important health benefits in Jiangsu Province, China, even in cities that meet the current CAAQS level 2 standard. Copyright © 2017 Elsevier Inc. All rights reserved.

Acute effect of ozone exposure on daily mortality in seven cities of Jiangsu Province, China: No clear evidence for threshold

PubMed Central

Chen, Kai; Zhou, Lian; Chen, Xiaodong; Bi, Jun; Kinney, Patrick L.

2017-01-01

Background Few multicity studies have addressed the health effects of ozone in China due to the scarcity of ozone monitoring data. A critical scientific and policy-relevant question is whether a threshold exists in the ozone-mortality relationship. Methods Using a generalized additive model and a univariate random-effects meta-analysis, this research evaluated the relationship between short-term ozone exposure and daily total mortality in seven cities of Jiangsu Province, China during 2013–2014. Spline, subset, and threshold models were applied to further evaluate whether a safe threshold level exists. Results This study found strong evidence that short-term ozone exposure is significantly associated with premature total mortality. A 10 μg/m3 increase in the average of the current and previous days’ maximum 8-h average ozone concentration was associated with a 0.55% (95% posterior interval: 0.34%, 0.76%) increase of total mortality. This finding is robust when considering the confounding effect of PM2.5, PM10, NO2, and SO2. No consistent evidence was found for a threshold in the ozone-mortality concentration-response relationship down to concentrations well below the current Chinese Ambient Air Quality Standard (CAAQS) level 2 standard (160 μg/m3). Conclusions Our findings suggest that ozone concentrations below the current CAAQS level 2 standard could still induce increased mortality risks in Jiangsu Province, China. Continuous air pollution control measures could yield important health benefits in Jiangsu Province, China, even in cities that meet the current CAAQS level 2 standard. PMID:28231551

Effect of Ventilation Strategies on Residential Ozone Levels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walker, Iain S.; Sherman, Max H.

Elevated outdoor ozone levels are associated with adverse health effects. Because people spend the vast majority of their time indoors, reduction in indoor levels of ozone of outdoor origin would lower population exposures and might also lead to a reduction in ozone-associated adverse health effects. In most buildings, indoor ozone levels are diminished with respect to outdoor levels to an extent that depends on surface reactions and on the degree to which ozone penetrates the building envelope. Ozone enters buildings from outdoors together with the airflows that are driven by natural and mechanical means, including deliberate ventilation used to reducemore » concentrations of indoor-generated pollutants. When assessing the effect of deliberate ventilation on occupant health one should consider not only the positive effects on removing pollutants of indoor origin but also the possibility that enhanced ventilation might increase indoor levels of pollutants originating outdoors. This study considers how changes in residential ventilation that are designed to comply with ASHRAE Standard 62.2 might influence indoor levels of ozone. Simulation results show that the building envelope can contribute significantly to filtration of ozone. Consequently, the use of exhaust ventilation systems is predicted to produce lower indoor ozone concentrations than would occur with balanced ventilation systems operating at the same air-­exchange rate. We also investigated a strategy for reducing exposure to ozone that would deliberately reduce ventilation rates during times of high outdoor ozone concentration while still meeting daily average ventilation requirements.« less

Future changes in the stratosphere-to-troposphere ozone mass flux and the contribution from climate change and ozone recovery

NASA Astrophysics Data System (ADS)

Meul, Stefanie; Langematz, Ulrike; Kröger, Philipp; Oberländer-Hayn, Sophie; Jöckel, Patrick

2018-06-01

Using a state-of-the-art chemistry-climate model we investigate the future change in stratosphere-troposphere exchange (STE) of ozone, the drivers of this change, as well as the future distribution of stratospheric ozone in the troposphere. Supplementary to previous work, our focus is on changes on the monthly scale. The global mean annual influx of stratospheric ozone into the troposphere is projected to increase by 53 % between the years 2000 and 2100 under the RCP8.5 greenhouse gas scenario. The change in ozone mass flux (OMF) into the troposphere is positive throughout the year with maximal increase in the summer months of the respective hemispheres. In the Northern Hemisphere (NH) this summer maximum STE increase is a result of increasing greenhouse gas (GHG) concentrations, whilst in the Southern Hemisphere(SH) it is due to equal contributions from decreasing levels of ozone depleting substances (ODS) and increasing GHG concentrations. In the SH the GHG effect is dominating in the winter months. A large ODS-related ozone increase in the SH stratosphere leads to a change in the seasonal breathing term which results in a future decrease of the OMF into the troposphere in the SH in September and October. The resulting distributions of stratospheric ozone in the troposphere differ for the GHG and ODS changes due to the following: (a) ozone input occurs at different regions for GHG- (midlatitudes) and ODS-changes (high latitudes); and (b) stratospheric ozone is more efficiently mixed towards lower tropospheric levels in the case of ODS changes, whereas tropospheric ozone loss rates grow when GHG concentrations rise. The comparison between the moderate RCP6.0 and the extreme RCP8.5 emission scenarios reveals that the annual global OMF trend is smaller in the moderate scenario, but the resulting change in the contribution of ozone with stratospheric origin (O3s) to ozone in the troposphere is of comparable magnitude in both scenarios. This is due to the larger tropospheric ozone precursor emissions and hence ozone production in the RCP8.5 scenario.

20-HETE mediates ozone-induced, neutrophil-independent airway hyper-responsiveness in mice.

PubMed

Cooper, Philip R; Mesaros, A Clementina; Zhang, Jie; Christmas, Peter; Stark, Christopher M; Douaidy, Karim; Mittelman, Michael A; Soberman, Roy J; Blair, Ian A; Panettieri, Reynold A

2010-04-20

Ozone, a pollutant known to induce airway hyper-responsiveness (AHR), increases morbidity and mortality in patients with obstructive airway diseases and asthma. We postulate oxidized lipids mediate in vivo ozone-induced AHR in murine airways. Male BALB/c mice were exposed to ozone (3 or 6 ppm) or filtered air (controls) for 2 h. Precision cut lung slices (PCLS; 250 microm thickness) containing an intrapulmonary airway ( approximately 0.01 mm(2) lumen area) were prepared immediately after exposure or 16 h later. After 24 h, airways were contracted to carbachol (CCh). Log EC(50) and E(max) values were then calculated by measuring the airway lumen area with respect to baseline. In parallel studies, dexamethasone (2.5 mg/kg), or 1-aminobenzotriazol (ABT) (50 mg/kg) were given intraperitoneal injection to naïve mice 18 h prior to ozone exposure. Indomethacin (10 mg/kg) was administered 2 h prior. Cell counts, cytokine levels and liquid chromatography-mass spectrometry (LC-MS) for lipid analysis were assessed in bronchoalveolar lavage (BAL) fluid from ozone exposed and control mice. Ozone acutely induced AHR to CCh. Dexamethasone or indomethacin had little effect on the ozone-induced AHR; while, ABT, a cytochrome P450 inhibitor, markedly attenuated airway sensitivity. BAL fluid from ozone exposed animals, which did not contain an increase in neutrophils or interleukin (IL)-6 levels, increased airway sensitivity following in vitro incubation with a naïve PCLS. In parallel, significant increases in oxidized lipids were also identified using LC-MS with increases of 20-HETE that were decreased following ABT treatment. These data show that ozone acutely induces AHR to CCh independent of inflammation and is insensitive to steroid treatment or cyclooxygenase (COX) inhibition. BAL fluid from ozone exposed mice mimicked the effects of in vivo ozone exposure that were associated with marked increases in oxidized lipids. 20-HETE plays a pivotal role in mediating acute ozone-induced AHR.

Trends in surface ozone concentrations at Arosa (Switzerland)

NASA Astrophysics Data System (ADS)

Staehelin, Johannes; Thudium, Juerg; Buehler, Ralph; Volz-Thomas, Andreas; Graber, Werner

During the years 1989-1991, ozone was measured at four sites around Arosa (Switzerland). One of these sites was identical with that, where surface ozone was measured in the 1950s (Götz and Volz, 1951; Perl, 1965). Comparison of both old and recent data indicates that surface ozone concentrations at Arosa have increased by a factor of approximately 2.2. The increase shows a seasonal variation with a relative increase of more than a factor of three in December and January. The results are discussed in the context of measurements made at other times, locations and altitudes. The comparison indicates that the increase in ozone levels at Arosa has most likely occured between the fifties and today. The measurements additionally suggest that photochemical ozone production in the free troposphere has significantly contributed to the observed ozone trends in winter.

Contribution of ozone to airborne aldehyde formation in Paris homes.

PubMed

Rancière, Fanny; Dassonville, Claire; Roda, Célina; Laurent, Anne-Marie; Le Moullec, Yvon; Momas, Isabelle

2011-09-15

Indoor aldehydes may result from ozone-initiated chemistry, mainly documented by experimental studies. As part of an environmental investigation included in the PARIS birth cohort, the aim of this study was to examine ozone contribution to airborne aldehyde formation in Paris homes. Formaldehyde, acetaldehyde and hexaldehyde levels, as well as styrene, nitrogen dioxide and nicotine concentrations, comfort parameters and carbon dioxide levels, were measured twice during the first year of life of the babies. Ambient ozone concentrations were collected from the closest background station of the regional air monitoring network. Traffic-related nitrogen oxide concentrations in front of the dwellings were estimated by an air pollution dispersion model. Home characteristics and families' way of life were described by questionnaires. Stepwise multiple linear regression models were used to link aldehyde levels with ambient ozone concentrations and a few aldehyde precursors involved in oxidation reactions, adjusting for other indoor aldehyde sources, comfort parameters and traffic-related nitrogen oxides. A 4 and 11% increase in formaldehyde and hexaldehyde levels was pointed out when 8-hour ozone concentrations increased by 20 μg/m(3). The influence of potential precursors such as indoor styrene level and frequent use of air fresheners, containing unsaturated volatile organic compounds as terpenes, was also found. Thus, our results suggest that ambient ozone can significantly impact indoor air quality, especially with regard to formaldehyde and hexaldehyde levels. Copyright © 2011 Elsevier B.V. All rights reserved.

Use of AIRS, OMI, MLS, and TES Data in Assessing Forest Ecosystem Exposure to Ozone

NASA Technical Reports Server (NTRS)

Spruce, Joseph P.

2007-01-01

Ground-level ozone at high levels poses health threats to exposed flora and fauna, including negative impacts to human health. While concern is common regarding depletion of ozone in the stratosphere, portions of the urban and rural United States periodically have high ambient levels of tropospheric ozone on the ground. Ozone pollution can cause a variety of impacts to susceptible vegetation (e.g., Ponderosa and Jeffrey pine species in the southwestern United States), such as stunted growth, alteration of growth form, needle or leaf chlorosis, and impaired ability to withstand drought-induced water stress. In addition, Southern Californian forests with high ozone exposures have been recently subject to multiyear droughts that have led to extensive forest overstory mortality from insect outbreaks and increased incidence of wildfires. Residual forests in these impacted areas may be more vulnerable to high ozone exposures and to other forest threats than ever before. NASA sensors collect a wealth of atmospheric data that have been used recently for mapping and monitoring regional tropospheric ozone levels. AIRS (Atmospheric Infrared Sounder), OMI (Ozone Monitoring Instrument), MLS (Microwave Limb Sounder), and TES (Tropospheric Emission Spectrometer) data could be used to assess forest ecosystem exposure to ozone. Such NASA data hold promise for providing better or at least complementary synoptic information on ground-level ozone levels that Federal agency partners can use to assess forest health trends and to mitigate the threats as needed in compliance with Federal laws and mandates. NASA data products on ozone concentrations may be able to aid applications of DSTs (decision support tools) adopted by the USDA FS (U.S. Department of Agriculture Forest Service) and by the NPS (National Park Service), such as the Ozone Calculator, in which ground ozone estimates are employed to assess ozone impacts to forested vegetation.

Evidence of a long-term increase in tropospheric ozone from Pic du Midi data series: Consequences: Positive radiative forcing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marenco, A.; Gouget, H.; Nedelec, P.

1994-08-01

The rate at which ozone is increasing in the troposphere is uncertain due to the lack of accurate long-term measurements. Old ozone measurements obtained at the Pic du Midi Observatory (3000 m high, southwestern France) were recently rediscovered. Four sets of data available at this station are presented. The results show an increase in ozone by a factor of 5 since the beginning of the twentieth century, corresponding to an exponential increase of 1.6% per year, although this trend is probably higher (2.4% per year) for the last few decades. A stable 10 ppb ozone mixing ratio is observed duringmore » the first 20 years of the series, which is representative to the preindustrial era ozone level. The increase is seen to start around 1895. Other data, obtained at various European high-altitude stations between 1920 and 1980, tie in closely with the Pic du Midi observations. A tentative evaluation of the impact of tropospheric ozone on radiative forcing confirms that ozone is currently the second most significant greenhouse gas, responsible for 22% and 13% of radiative forcing changes since 1800 in the northern and southern hemispheres, respectively. If these rates were to be maintained in the future, ozone would continue to evolve differently in the two hemispheres (maximum level in the northern hemisphere) and could make an even more significant contribution to the radiative forcing of the northern hemisphere.« less

Ozone concentrations and damage for realistic future European climate and air quality scenarios

NASA Astrophysics Data System (ADS)

Hendriks, Carlijn; Forsell, Nicklas; Kiesewetter, Gregor; Schaap, Martijn; Schöpp, Wolfgang

2016-11-01

Ground level ozone poses a significant threat to human health from air pollution in the European Union. While anthropogenic emissions of precursor substances (NOx, NMVOC, CH4) are regulated by EU air quality legislation and will decrease further in the future, the emissions of biogenic NMVOC (mainly isoprene) may increase significantly in the coming decades if short-rotation coppice plantations are expanded strongly to meet the increased biofuel demand resulting from the EU decarbonisation targets. This study investigates the competing effects of anticipated trends in land use change, anthropogenic ozone precursor emissions and climate change on European ground level ozone concentrations and related health and environmental impacts until 2050. The work is based on a consistent set of energy consumption scenarios that underlie current EU climate and air quality policy proposals: a current legislation case, and an ambitious decarbonisation case. The Greenhouse Gas-Air Pollution Interactions and Synergies (GAINS) integrated assessment model was used to calculate air pollutant emissions for these scenarios, while land use change because of bioenergy demand was calculated by the Global Biosphere Model (GLOBIOM). These datasets were fed into the chemistry transport model LOTOS-EUROS to calculate the impact on ground level ozone concentrations. Health damage because of high ground level ozone concentrations is projected to decline significantly towards 2030 and 2050 under current climate conditions for both energy scenarios. Damage to plants is also expected to decrease but to a smaller extent. The projected change in anthropogenic ozone precursor emissions is found to have a larger impact on ozone damage than land use change. The increasing effect of a warming climate (+2-5 °C across Europe in summer) on ozone concentrations and associated health damage, however, might be higher than the reduction achieved by cutting back European ozone precursor emissions. Global action to reduce air pollutant emissions is needed to make sure that ozone damage in Europe decreases towards the middle of this century.

Soybean Cultivar Variation in Response to Elevated Ozone Concentration

USDA-ARS?s Scientific Manuscript database

Crop losses to ozone damage are conservatively estimated to cost $1 to $3 billion in the U.S. These costs will rise as surface-level ozone increases over this century. A critical step in maximizing soybean yield in a future of rising tropospheric ozone is identifying variation in cultivar responses,...

Differential regulation of the lung endothelin system by urban particulate matter and ozone.

PubMed

Thomson, Errol; Kumarathasan, Prem; Goegan, Patrick; Aubin, Rémy A; Vincent, Renaud

2005-11-01

Periodic elevation of ambient particulate matter and ozone levels is linked to acute cardiac morbidity and mortality. Increased plasma levels of the potent vasoconstrictor endothelin (ET)-1, a prognostic indicator of cardiac mortality, have been detected in both animal models and humans after exposure to air pollutants. The lungs are the primary source of circulating ET-1, but the direct effects of individual air pollutants and their interaction in modulating the pulmonary endothelin system are unknown. Fischer-344 rats were exposed to particles (0, 5, 50 mg/m3 EHC-93), ozone (0, 0.4, 0.8 ppm), or combinations of particles and ozone for 4 h. Changes in gene expression were measured using real-time reverse transcription polymerase chain reaction immediately after exposure and following 24 h recovery in clean air. Both pollutants individually increased preproET-1, endothelin converting enzyme-1, and endothelial nitric oxide synthase mRNA levels in the lungs shortly after exposure, consistent with the concomitant increase in plasma of the 21 amino acid ET-1[1-21] peptide measured by HPLC-fluorescence. PreproET-1 mRNA remained elevated 24 h after exposure to particles but not after ozone, in line with previously documented changes of the peptide in plasma. Both pollutants transiently increased endothelin-B receptor mRNA expression, while ozone decreased endothelin-A receptor mRNA levels. Coexposure to particles plus ozone increased lung preproET-1 mRNA but not plasma ET-1[1-21], suggesting alternative processing or degradation of endothelins. This coincided with an increase in the lungs of matrix metalloproteinase-2 (MMP-2), an enzyme that cleaves bigET-1 to ET-1[1-32]. Taken together, our data indicate that ozone and particulate matter independently regulate the expression of lung endothelin system genes, but show complex toxicological interaction with respect to plasma ET-1.

Effects of simulated acid rain and ozone on foliar chemistry of field-grown Pinus ponderosa seedlings and mature trees.

PubMed

Momen, B; Helms, J A

1996-01-01

We investigated the additive and interactive effects of simulated acid rain and elevated ozone on C and N contents, and the C:N ratio of one-year-old and current-year foliage of field-grown mature trees and their half-sib seedlings of a stress tolerant genotype of ponderosa pine. Acid rain levels (pH 5.1 and 3.0) were applied weekly to foliage only (no soil acidification or N addition), from January to April, 1992. Plants were exposed to two ozone levels (ambient and twice-ambient) during the day from September 1991 to November 1992. The sequential application of acid rain and elevated ozone mimicked the natural conditions. Twice-ambient ozone significantly decreased foliar N content (by 12-14%) and increased the C:N ratio of both one-year-old and current-year foliage of seedlings. Although similar ozone effects were also observed on one-year-old foliage of mature trees, the only statistically significant effect was an increased C:N ratio when twice-ambient ozone combined with pH 3.0 rain (acid rain by ozone interaction). Enhancing the effect of twice-ambient ozone in increasing the C:N ratio of one-year-old foliage of mature trees in June was the only significant effect of acid rain.

Application and further characterization of the snap bean S156/R123 ozone biomonitoring system in relation to ambient air temperature

USDA-ARS?s Scientific Manuscript database

Increased mixing ratios of ground-level ozone threaten individual plants, plant communities and ecosystems. In this sense, ozone biomonitoring is of great interest. The ozone-sensitive S156 and the ozone-tolerant R123 genotypes of snap bean (Phaseolus vulgaris L.) have been proposed as a potential t...

Chronic Exposure to Ambient Ozone and Asthma Hospital Admissions among Children

PubMed Central

Lin, Shao; Liu, Xiu; Le, Linh H.; Hwang, Syni-An

2008-01-01

Background The association between chronic exposure to air pollution and adverse health outcomes has not been well studied. Objective This project investigated the impact of chronic exposure to high ozone levels on childhood asthma admissions in New York State. Methods We followed a birth cohort born in New York State during 1995–1999 to first asthma admission or until 31 December 2000. We identified births and asthma admissions through the New York State Integrated Child Health Information System and linked these data with ambient ozone data (8-hr maximum) from the New York State Department of Environmental Conservation. We defined chronic ozone exposure using three indicators: mean concentration during the follow-up period, mean concentration during the ozone season, and proportion of follow-up days with ozone levels > 70 ppb. We performed logistic regression analysis to adjust for child’s age, sex, birth weight, and gestational age; maternal race/ethnicity, age, education, insurance status, smoking during pregnancy, and poverty level; and geographic region, temperature, and copollutants. Results Asthma admissions were significantly associated with increased ozone levels for all chronic exposure indicators (odds ratios, 1.16–1.68), with a positive dose–response relationship. We found stronger associations among younger children, low sociodemographic groups, and New York City residents as effect modifiers. Conclusion Chronic exposure to ambient ozone may increase the risk of asthma admissions among children. Younger children and those in low socioeconomic groups have a greater risk of asthma than do other children at the same ozone level. PMID:19079727

Quantifying Ozone Production throughout the Boundary Layer from High Frequency Tethered Profile Measurements during a High Ozone Episode in the Uinta Basin, Utah

NASA Astrophysics Data System (ADS)

Sterling, C. W.; Johnson, B.; Schnell, R. C.; Oltmans, S. J.; Cullis, P.; Hall, E. G.; Jordan, A. F.; Windell, J.; McClure-Begley, A.; Helmig, D.; Petron, G.

2015-12-01

During the Uinta Basin Winter Ozone Study (UBWOS) in Jan - Feb 2013, 735 tethered ozonesonde profiles were obtained at 3 sites including during high wintertime photochemical ozone production events that regularly exceeded 125 ppb. High resolution profiles of ozone and temperature with altitude, measured during daylight hours, showed the development of approximately week long high ozone episodes building from background levels of ~40 ppb to >150 ppb. The topography of the basin combined with a strong temperature inversion trapped oil and gas production effluents in the basin and the snow covered surface amplified the sun's radiation driving the photochemical ozone production at rates up to 13 ppb/hour in a cold layer capped at 1600-1700 meters above sea level. Beginning in mid-morning, ozone mixing ratios throughout the cold layer increased until late afternoon. Ozone mixing ratios were generally constant with height indicating that ozone production was nearly uniform throughout the depth of the cold pool. Although there was strong diurnal variation, ozone mixing ratios increased during the day more than decreased during the night, resulting in elevated levels the next morning; an indication that nighttime loss processes did not compensate for daytime production. Even though the 3 tethersonde sites were at elevations differing by as much as 140 m, the top of the high ozone layer was nearly uniform in altitude at the 3 locations. Mobile van surface ozone measurements across the basin confirmed this capped structure of the ozone layer; the vehicle drove out of high ozone mixing ratios at an elevation of ~1900 meters above sea level, above which free tropospheric ozone mixing ratios of ~50 ppb were measured. Exhaust plumes from a coal-fired power plant in the eastern portion of the basin were intercepted by the tethersondes. The structure of the profiles clearly showed that effluents in the plumes were not mixed downward and thus did not contribute precursor nitrogen oxides to the observed ozone production in the boundary layer.

RNA-Seq study reveals genetic responses of diverse wild soybean accessions to increased ozone levels.

PubMed

Waldeck, Nathan; Burkey, Kent; Carter, Thomas; Dickey, David; Song, Qijian; Taliercio, Earl

2017-06-29

Ozone is an air pollutant widely known to cause a decrease in productivity in many plant species, including soybean (Glycine max (L.) Merr). While the response of cultivated soybean to ozone has been studied, very little information is available regarding the ozone response of its wild relatives. Ozone-resistant wild soybean accessions were identified by measuring the response of a genetically diverse group of 66 wild soybean (Glycine soja Zucc. and Sieb.) accessions to elevated ozone levels. RNA-Seq analyses were performed on leaves of different ages from selected ozone-sensitive and ozone-resistant accessions that were subjected to treatment with an environmentally relevant level of ozone. Many more genes responded to elevated ozone in the two ozone-sensitive accessions than in the ozone-resistant accessions. Analyses of the ozone response genes indicated that leaves of different ages responded differently to ozone. Older leaves displayed a consistent reduction in expression of genes involved in photosynthesis in response to ozone, while changes in expression of defense genes dominated younger leaf tissue in response to ozone. As expected, there is a substantial difference between the response of ozone-sensitive and ozone-resistant accessions. Genes associated with photosystem 2 were substantially reduced in expression in response to ozone in the ozone-resistant accessions. A decrease in peptidase inhibitors was one of several responses specific to one of the ozone resistant accessions. The decrease in expression in genes associated with photosynthesis confirms that the photosynthetic apparatus may be an early casualty in response to moderate levels of ozone. A compromise of photosynthesis would substantially impact plant growth and seed production. However, the resistant accessions may preserve their photosynthetic apparatus in response to the ozone levels used in this study. Older leaf tissue of the ozone-resistant accessions showed a unique down-regulation of genes associated with endopeptidase inhibitor activity. This study demonstrates the existence of significant diversity in wild soybean for ozone response. Wild soybean accessions characterized in this study can be used by soybean breeders to enhance ozone tolerance of this important food crop.

Physiological and genotype-specific factors associated with grain quality changes in rice exposed to high ozone.

PubMed

Jing, Liquan; Dombinov, Vitalij; Shen, Shibo; Wu, Yanzhen; Yang, Lianxin; Wang, Yunxia; Frei, Michael

2016-03-01

Rising tropospheric ozone concentrations in Asia affect the yield and quality of rice. This study investigated ozone-induced changes in rice grain quality in contrasting rice genotypes, and explored the associated physiological processes during the reproductive growth phase. The ozone sensitive variety Nipponbare and a breeding line (L81) containing two tolerance QTLs in Nipponbare background were exposed to 100 ppb ozone (8 h per day) or control conditions throughout their growth. Ozone affected grain chalkiness and protein concentration and composition. The percentage of chalky grains was significantly increased in Nipponbare but not in L81. Physiological measurements suggested that grain chalkiness was associated with a drop in foliar carbohydrate and nitrogen levels during grain filling, which was less pronounced in the tolerant L81. Grain total protein concentration was significantly increased in the ozone treatment, although the albumin fraction (water soluble protein) decreased. The increase in protein was more pronounced in L81, due to increases in the glutelin fraction in this genotype. Amino acids responded differently to the ozone treatment. Three essential amino acids (leucine, methionine and threonine) showed significant increases, while seven showed significant treatment by genotype interactions, mostly due to more positive responses in L81. The trend of increased grain protein was in contrast to foliar nitrogen levels, which were negatively affected by ozone. A negative correlation between grain protein and foliar nitrogen in ozone stress indicated that higher grain protein cannot be explained by a concentration effect in all tissues due to lower biomass production. Rather, ozone exposure affected the nitrogen distribution, as indicated by altered foliar activity of the enzymes involved in nitrogen metabolism, such as glutamine synthetase and glutamine-2-oxoglutarate aminotransferase. Our results demonstrate differential responses of grain quality to ozone due to the presence of tolerance QTL, and partly explain the underlying physiological processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Use of Ozone to Treat Ileostomy Dermatitis in an Experimental Rat Model.

PubMed

Biçer, Şenol; Sayar, İlyas; Gürsul, Cebrail; Işık, Arda; Aydın, Merve; Peker, Kemal; Demiryilmaz, İsmail

2016-03-07

Dermatitis associated with ileostomy is an important problem that affects many people, especially children. The aim of this study was to investigate the therapeutic effects of ozone on dermatitis due to ileostomy, and to develop an alternative treatment option. A total of 28 rats were divided into 4 groups: control, ileostomy, ozone, and zinc oxide. Ileostomy was performed in all rats except the control group. After a 1-week waiting time, the ozone group was administered ozone therapy and the zinc oxide group was administered zinc oxide cream locally once a day for a total of 7 days. All rats were sacrificed at the end of this period. The efficacy of treatment was examined by biochemical, histopathological, and immunohistochemical parameters. The levels of malondialdehyde (MDA), total glutathione (tGSH), total antioxidant capacity (TAC), and total oxidant status (TOS) were measured from tissue. Vascular endothelial growth factor (VEGF) and proliferating cell nuclear antigen (PCNA) were examined immunohistochemically. Dermatitis occurred pathologically in all rats that underwent ileostomy surgery. The lowest dermatitis score was in the ozone treatment group (p<0.05). Ileostomy dermatitis caused increased levels of MDA and TOS. Ozone treatment resulted in reduced MDA and TOS levels, while the levels of tGSH and TAC were increased (p<0.05). Both VEGF and PCNA immunostaining were augmented in the ozone treatment group (p<0.05). Local ozone application may be a good alternative compared to the conventional treatment methods for the prevention of skin lesions that develop after ileostomy.

Modeling of Regional Climate Change Effects on Ground-Level Ozone and Childhood Asthma

PubMed Central

Sheffield, Perry E.; Knowlton, Kim; Carr, Jessie L.; Kinney, Patrick L.

2011-01-01

Background The adverse respiratory effects of ground-level ozone are well-established. Ozone is the air pollutant most consistently projected to increase under future climate change. Purpose To project future pediatric asthma emergency department visits associated with ground-level ozone changes, comparing 1990s to 2020s. Methods This study assessed future numbers of asthma emergency department visits for children aged 0–17 years using (1) baseline New York City metropolitan area emergency department rates, (2) a dose–response relationship between ozone levels and pediatric asthma emergency department visits, and (3) projected daily 8-hour maximum ozone concentrations for the 2020s as simulated by a global-to-regional climate change and atmospheric chemistry model. Sensitivity analyses included population projections and ozone precursor changes. This analysis occurred in 2010. Results In this model, climate change could cause an increase in regional summer ozone-related asthma emergency department visits for children aged 0–17 years of 7.3% across the New York City metropolitan region by the 2020s. This effect diminished with inclusion of ozone precursor changes. When population growth is included, the projections of morbidity related to ozone are even larger. Conclusions The results of this analysis demonstrate that the use of regional climate and atmospheric chemistry models make possible the projection of local climate change health effects for specific age groups and specific disease outcomes – such as emergency department visits for asthma. Efforts should be made to improve on this type of modeling to inform local and wider-scale climate change mitigation and adaptation policy. PMID:21855738

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haque, Rizwanul; Umstead, Todd M.; Ponnuru, Padmavathi

Millions are exposed to ozone levels above recommended limits, impairing lung function, causing epithelial damage and inflammation, and predisposing some individuals to pneumonia, asthma, and other lung conditions. Surfactant protein-A (SP-A) plays a role in host defense, the regulation of inflammation, and repair of tissue damage. We tested the hypothesis that the lungs of SP-A(-/-) (KO) mice are more susceptible to ozone-induced damage. We compared the effects of ozone on KO and wild type (WT) mice on the C57BL/6 genetic background by exposing them to 2 parts/million of ozone for 3 or 6 h and sacrificing them 0, 4, andmore » 24 h later. Lungs were subject to bronchoalveolar lavage (BAL) or used to measure endpoints of oxidative stress and inflammation. Despite more total protein in BAL of KO mice after a 3 h ozone exposure, WT mice had increased oxidation of protein and had oxidized SP-A dimers. In KO mice there was epithelial damage as assessed by increased LDH activity and there was increased phospholipid content. In WT mice there were more BAL PMNs and elevated macrophage inflammatory protein (MIP)-2 and monocyte chemoattractant protein (MCP)-1. Changes in MIP-2 and MCP-1 were observed in both KO and WT, however mRNA levels differed. In KO mice MIP-2 mRNA levels changed little with ozone, but in WT levels they were significantly increased. In summary, several aspects of the inflammatory response differ between WT and KO mice. These in vivo findings appear to implicate SP-A in regulating inflammation and limiting epithelial damage in response to ozone exposure.« less

Change in ozone trends at southern high latitudes

NASA Technical Reports Server (NTRS)

Yang, E.-S.; Cunnold, D. M.; Newchurch, M. J.; Salawitch, R. J.

2005-01-01

Long-term ozone variations at 60-70degS in spring are investigated using ground-based and satellite measurements. Strong positive correlation is shown between year-to-year variations of ozone and temperature in the Antarctic collar region in Septembers and Octobers. Based on this relationship, the effect of year-to-year variations in vortex dynamics has been filtered out. This process results in an ozone time series that shows increasing springtime ozone losses over the Antarctic until the mid-1990s. Since approximately 1997 the ozone losses have leveled off. The analysis confirms that this change is consistent across all instruments and is statistically significant at the 95% confidence level. This analysis quantifies the beginning of the recovery of the ozone hole, which is expected from the leveling off of stratospheric halogen loading due to the ban on CFCs and other halocarbons initiated by the Montreal Protocol.

Spatial distribution of ozone over Indonesia (Study case: Forest fire event 2015)

NASA Astrophysics Data System (ADS)

Muslimah, Sri; Buce Saleh, Muhamad; Hidayat, Rahmat

2018-05-01

Tropospheric ozone is known as surface ozone and caused several health impact. The objective of this study was to analysis spatial distribution of tropospheric ozone over Indonesia case study forest fire event in 2015. Monthly observation measured by Ozone Monitoring Instrument (OMI) have been analysed from January – December 2015 to study spatial distribution of tropospheric ozone related to forest fire event 2015. The study discovered high level of tropospheric column ozone (TCO) from October to November 2015. The result shows increasing average of TCO from September to October almost 6 DU. Meanwhile, monthly number of hotspot is higher in September 2015 with total number 257 hotspot which is acquired by Moderate Resolution Imaging Spectrometer (MODIS) Terra version 6.1 with confidence level same or more than 90%. The hotspot distribution compared with spatial TCO distribution and shows interesting time lag with respect to hotspot distribution, one month. Further study for daily comparison of TCO and forest fire event needed. This result suggested that the tropospheric ozone over the Indonesian region increases in 2015 were remarkable and corresponded to forest fire event.

Vertical profiles reveal impact of ozone and temperature on carbon assimilation of Betula pendula and Populus tremula.

PubMed

Mäenpää, Maarit; Riikonen, Johanna; Kontunen-Soppela, Sari; Rousi, Matti; Oksanen, Elina

2011-08-01

Rising temperature and tropospheric ozone (O(3)) concentrations are likely to affect carbon assimilation processes and thus the carbon sink strength of trees. In this study, we investigated the joint action of elevated ozone and temperature on silver birch (Betula pendula) and European aspen (Populus tremula) saplings in field conditions by combining free-air ozone exposure (1.2 × ambient) and infrared heaters (ambient +1.2 °C). At leaf level measurements, elevated ozone decreased leaf net photosynthesis (P(n)), while the response to elevated temperature was dependent on leaf position within the foliage. This indicates that leaf position has to be taken into account when leaf level data are collected and applied. The ozone effect on P(n) was partly compensated for at elevated temperature, showing an interactive effect of the treatments. In addition, the ratio of photosynthesis to stomatal conductance (P(n)/g(s) ratio) was decreased by ozone, which suggests decreasing water use efficiency. At the plant level, the increasing leaf area at elevated temperature resulted in a considerable increase in photosynthesis and growth in both species.

Is Ozone Going Up Now?

NASA Astrophysics Data System (ADS)

Steinbrecht, W.; Froidevaux, L.; Davis, S. M.; Degenstein, D. A.; Wild, J.; Roth, C.; Kaempfer, N.; Leblanc, T.; Godin-Beekmann, S.; Vigouroux, C.; Swart, D. P. J.; Querel, R.; Harris, N.; Nedoluha, G. E.

2016-12-01

The last WMO ozone assessment (WMO, 2014) concluded that observations show significant ozone increase, 3% per decade (±2% per decade, 2σ), in the upper stratosphere since 2000. At other levels, or for total ozone, increases were not found or not significant. Overall, this is consistent with expectations from model simulations, (e.g. CCMVal2, Eyring et al., 2010). These simulations indicate that declining chlorine levels and stratospheric cooling due to CO2 increase should contribute roughly equal parts to ozone increase in the upper stratosphere. Shortly after the assessment, results from the SI2N initiative (Harris et al., 2015) confirmed increasing ozone in the upper stratosphere. However, the SI2N results indicated smaller increases (+1.5% per decade) than the WMO assessment, and substantially larger uncertainties (±5% per decade, 2σ). Differences can be attributed to time period, 1998 to 2012, compared to 2000 to 2013/14 for the assessment, and to larger assumed instrumental drift uncertainties, 6% per decade, (only 1 to 2% per decade in WMO 2014, see also Hubert et al., 2016). Here, we explore how additional ground-based and satellite data since 2013, as well as new and improved records, affect ozone trends and uncertainties. The focus will be on ozone in the upper stratosphere, because this is the region where the earliest signs of beginning ozone recovery are expected. ReferencesEyring, V., et al.: Multi-model assessment of stratospheric ozone return dates and ozone recovery in CCMVal-2 models, Atmos. Chem. Phys., 10, 9451-9472, doi:10.5194/acp-10-9451-2010, 2010. Harris, N. R. P., et al.: Past changes in the vertical distribution of ozone - Part 3: Analysis and interpretation of trends, Atmos. Chem. Phys., 15, 9965-9982, doi:10.5194/acp-15-9965-2015, 2015. Hubert, D., et al.: Ground-based assessment of the bias and long-term stability of fourteen limb and occultation ozone profile data records, Atmos. Meas. Tech., 9, 2497-2534, doi:10.5194/amt-9-2497-2016, 2016. WMO 2014: Pawson, S., Steinbrecht, W. et al.: Update on global ozone: Past, present, and future, Chapter 2 in: Scientific Assessment of Ozone Depletion: 2014, Global Ozone Research and Monitoring Project - Report No. 55, World Meteorological Organization, Geneva, Switzerland, 2014.

Mixing Heights and Three-Dimensional Ozone Structure Observed by Airborne Lidar During the 2006 Texas Air Quality Study

NASA Astrophysics Data System (ADS)

Hardesty, R. M.; Senff, C. J.; Alvarez, R. J.; Banta, R. M.; Sandberg, S. P.; Weickmann, A. M.; Darby, L. S.

2007-12-01

A new all solid state ozone lidar was deployed on a NOAA Twin Otter to study boundary layer ozone and aerosol, mostly around Houston, during the 2006 Texas Air Quality Study. The new instrument transmits high pulse-rate, low pulse-energy light at 3 wavelengths in the ultraviolet to obtain ozone profiles with 500 m horizontal resolution and 90 m vertical resolution. During the Texas field study, 20 research flights resulted in nearly 70 hours of ozone measurements during the period from August 1 to September 15. Science objectives included characterization of background ozone levels over rural areas near Houston and Dallas and variability and structure of the boundary layer over different surface types, including urban, wooded, and agricultural land surface areas as well as over Galveston Bay and the Gulf of Mexico. A histogram of all boundary layer ozone concentration measurements showed a bimodal distribution with modes at 45 ppb and 70 ppb. The lower mode correlated with southerly flow, when relatively clean air was transported onshore into the Houston area. Segmenting the observations during southerly flow by region, including the Gulf of Mexico, land within about 55 km from the coast, and further inland indicated that background levels increased by about 10 ppb as air was transported onshore. During the latter part of the experiment, as more pollution was imported into the Houston region, background levels rose to nearly 80 ppb in regions N of Houston. Two flights aimed at observing import of ozone into Texas from the east showed that ozone concentrations increased and boundary layer depths deepened upwind of Houston between September 4 and September 8. Background levels rose by more than 10 ppb over this period. In addition to ozone measurements, we also estimated boundary layer height based on maximum gradient in observed backscatter. The technique worked well when the layer topped by the strongest gradient extends down to the surface. Investigation of the correlation between ozone levels and mixing layer heights both within and external to the Houston urban plume showed a variety of relationships, depending on, e.g., wind direction and occurrence of a bay/gulf breeze. On a day-to-day basis, higher ozone levels were weakly correlated with deeper mixing levels - this was likely due to advection of the urban heat island downwind with the high-ozone urban plume.

Additive Effect of Diesel Exhaust Particulates and Ozone on Airway Hyperresponsiveness and Inflammation in a Mouse Model of Asthma

PubMed Central

Choi, Inseon-S; Takizawa, Hajime; Rhim, TaiYoun; Lee, June-Hyuk; Park, Sung-Woo; Park, Choon-Sik

2005-01-01

Allergic airway diseases are related to exposure to atmospheric pollutants, which have been suggested to be one factor in the increasing prevalence of asthma. Little is known about the effect of ozone and diesel exhaust particulates (DEP) on the development or aggravation of asthma. We have used a mouse asthma model to determine the effect of ozone and DEP on airway hyperresponsiveness and inflammation. Methacholine enhanced pause (Penh) was measured. Levels of IL-4 and IFN-γ were quantified in bronchoalveolar lavage fluids by enzyme immunoassays. The OVA-sensitized-challenged and ozone and DEP exposure group had higher Penh than the OVA-sensitized-challenged group and the OVA-sensitized-challenged and DEP exposure group, and the OVA-sensitized-challenged and ozone exposure group. Levels of IFN-γ were decreased in the OVA-sensitized-challenged and DEP exposure group and the OVA-sensitized-challenged and ozone and DEP exposure group compared to the OVA-sensitized-challenged and ozone exposure group. Levels of IL-4 were increased in the OVA-sensitized-challenged and ozone exposure group and the OVA-sensitized-challenged and DEP exposure group, and the OVA-sensitized-challenged and ozone and DEP exposure group compared to OVA-sensitized-challenged group. Co-exposure of ozone and DEP has additive effect on airway hyperresponsiveness by modulation of IL-4 and IFN-γ suggesting that DEP amplify Th2 immune response. PMID:16224148

A two-dimensional model with coupled dynamics, radiative transfer, and photochemistry. 2: Assessment of the response of stratospheric ozone to increased levels of CO2, N2O, CH4, and CFC

NASA Technical Reports Server (NTRS)

Schneider, Hans R.; Ko, Malcolm K. W.; Shia, Run-Lie; Sze, Nien-Dak

1993-01-01

The impact of increased levels of carbon dioxide (CO2), chlorofluorocarbons (CFCs), and other trace gases on stratospheric ozone is investigated with an interactive, two-dimensional model of gas phase chemistry, dynamics, and radiation. The scenarios considered are (1) a doubling of the CO2 concentration, (2) increases of CFCs, (3) CFC increases combined with increases of nitrous oxide (N2O) and methane CH4, and (4) the simultaneous increase of CO2, CFCs, N2O, and CH4. The radiative feedback and the effect of temperature and circulation changes are studied for each scenario. For the double CO2 calculations the tropospheric warming was specified. The CO2 doubling leads to a 3.1% increase in the global ozone content. Doubling of the CO2 concentrations would lead to a maximum cooling of about 12 C at 45 km if the ozone concentration were held fixed. The cooling of the stratosphere leads to an ozone increase with an associated increase in solar heating, reducing the maximum temperature drop by about 3 C. The CFC increase from continuous emissions at 1985 rate causes a 4.5% loss of ozone. For the combined perturbations a net loss of 1.3% is calculated. The structure of the perturbations shows a north-south asymmetry. Ozone losses (when expressed in terms of percent changes) are generally larger in the high latitudes of the southern hemisphere as a result of the eddy mixing being smaller than in the northern hemisphere. Increase of chlorine leads to ozone losses above 30 km altitude where the radiative feedback results in a cooler temperature and an ozone recovery of about one quarter of the losses predicted with a noninteractive model. In all the cases, changes in circulation are small. In the chlorine case, circulation changes reduce the calculated column depletion by about one tenth compared to offline calculations.

Changes in the photochemical environment of the temperate North Pacific troposphere in response to increased Asian emissions

NASA Astrophysics Data System (ADS)

Parrish, D. D.; Dunlea, E. J.; Atlas, E. L.; Schauffler, S.; Donnelly, S.; Stroud, V.; Goldstein, A. H.; Millet, D. B.; McKay, M.; Jaffe, D. A.; Price, H. U.; Hess, P. G.; Flocke, F.; Roberts, J. M.

2004-12-01

Measurements during the Intercontinental Transport and Chemical Transformation 2002 (ITCT 2K2) field study characterized the springtime, eastern Pacific ozone distribution at two ground sites, from the National Oceanic and Atmospheric Administration WP-3D aircraft, and from a light aircraft operated by the University of Washington. D. Jaffe and colleagues compared the 2002 ozone distribution with measurements made in the region over the two previous decades and show that average ozone levels over the eastern midlatitude Pacific have systematically increased by ˜10 ppbv in the last two decades. Here we provide substantial evidence that a marked change in the photochemical environment in the springtime troposphere of the North Pacific is responsible for this increased O3. This change is evidenced in the eastern North Pacific ITCT 2K2 study region by (1) larger increases in the minimum observed ozone levels compared to more modest increases in the maximum levels, (2) increased peroxyacetyl nitrate (PAN) levels that parallel trends in NOx emissions, and (3) decreased efficiency of photochemical O3 destruction, i.e., less negative O3 photochemical tendency (or net rate of O3 photochemical production; P(O3)). This changed photochemical environment is hypothesized to be due to anthropogenic emissions from Asia, which are believed to have substantially increased over the two decades preceding the study. We propose that their influence has changed the springtime Pacific tropospheric photochemistry from predominately ozone destroying to more nearly ozone producing. However, chemical transport model calculations indicate the possible influence of a confounding factor; unusual transport of tropical air to the western North Pacific during one early field study may have played a role in this apparent change in the photochemistry.

Increase in ozone due to the use of biodiesel fuel rather than diesel fuel.

PubMed

Thang, Phan Quang; Muto, Yusuke; Maeda, Yasuaki; Trung, Nguyen Quang; Itano, Yasuyuki; Takenaka, Norimichi

2016-09-01

The consumption of fuel by vehicles emits nitrogen oxides (NOx) and non-methane hydrocarbons (NMHCs) into the atmosphere, which are important ozone precursors. Ozone is formed as a secondary pollutant via photochemical processes and is not emitted directly into the atmosphere. In this paper, the ozone increase resulting from the use of biodiesel and diesel fuels was investigated, and the different ozone formation trends were experimentally evaluated. Known amounts of exhaust gas from a power generator operated using biodiesel and diesel fuels were added to ambient air. The quality of the ambient air, such as the initial NMHC and NOx concentrations, and the irradiation intensity have an effect on the ozone levels. When 30 cm(3) of biodiesel fuel exhaust gas (BFEG) or diesel fuel exhausted gas (DFEG) was added to 18 dm(3) of ambient air, the highest ratios of ozone increase from BFEG compared with DFEG in Japan and Vietnam were 31.2 and 42.8%, respectively, and the maximum ozone increases resulting from DFEG and BFEG compared with the ambient air in Japan were 17.4 and 26.4 ppb, respectively. The ozone increase resulting from the use of BFEG was large and significant compared to that from DFEG under all experimental conditions. The ozone concentration increased as the amount of added exhaust gas increased. The ozone increase from the Jatropha-BFEG was slightly higher than that from waste cooking oil-BFEG. Copyright © 2016 Elsevier Ltd. All rights reserved.

Attribution of Recovery in Lower-Stratospheric Ozone

NASA Technical Reports Server (NTRS)

Yang, Eun-Su; Cunnold, Derek M.; Salawitch, Ross J.; McCormick, M. Patrick; Russell, James, III; Zawodny, Joseph M.; Oltmans, Samuel; Newchurch, Michael J.

2005-01-01

Multiple satellite and ground-based observations provide consistent evidence that the thickness of Earth's protective ozone layer has stopped declining since 1997, close to the time of peak stratospheric halogen loading. Regression analyses with Effective Equivalent Stratospheric Chlorine (EESC) in conjunction with further analyses using more sophisticated photochemical model calculations constrained by satellite data demonstrate that the cessation of ozone depletion between 18-25 km altitude is consistent with a leveling off of stratospheric abundances of chlorine and bromine, due to the Montreal Protocol and its amendments. However, ozone increases in the lowest part of the stratosphere, from the tropopause to 18 km, account for about half of the improvement in total column ozone during the past 9 years at northern hemisphere mid-latitudes. The increase in ozone for altitudes below 18 km is most likely driven by changes in transport, rather than driven by declining chlorine and bromine. Even with this evidence that the Montreal Protocol and its amendments are having the desired, positive effect on ozone above 18 km, total column ozone is recovering faster than expected due to the apparent transport driven changes at lower altitudes. Accurate prediction of future levels of stratospheric ozone will require comprehensive understanding of the factors that drive temporal changes at various altitudes, and partitioning of the recent transport-driven increases between natural variability and changes in atmospheric structure perhaps related to anthropogenic climate change.

Attribution of Recovery in Lower-stratospheric Ozone

NASA Technical Reports Server (NTRS)

Yang, Eun-Su; Cunnold, Derek M.; Salawitch, Ross J.; McCormick, M. Patrick; Russell, James, III; Zawodny, Joseph M.; Oltmans, Samuel; Newchurch, Michael J.

2006-01-01

Multiple satellite and ground-based observations provide consistent evidence that the thickness of Earth's protective ozone layer has stopped declining since 1997, close to the time of peak stratospheric halogen loading. Regression analyses with Effective Equivalent Stratospheric Chlorine (EESC) in conjunction with further analyses using more sophisticated photochemical model calculations constrained by satellite data demonstrate that the cessation of ozone depletion between 18-25 km altitude is consistent with a leveling off of stratospheric abundances of chlorine and bromine, due to the Montreal Protocol and its amendments. However, ozone increases in the lowest part of the stratosphere, from the tropopause to 18 km, account for about half of the improvement in total column ozone during the past 9 years at northern hemisphere mid-latitudes. The increase in ozone for altitudes below 18 km is most likely driven by changes in transport, rather than driven by declining chlorine and bromine. Even with this evidence that the Montreal Protocol and its amendments are having the desired, positive effect on ozone above 18 km, total column ozone is recovering faster than expected due to the apparent transport driven changes at lower altitudes. Accurate prediction of future levels of stratospheric ozone will require comprehensive understanding of the factors that drive temporal changes at various altitudes, and partitioning of the recent transport-driven increases between natural variability and changes in atmospheric structure perhaps related to anthropogenic climate change.

Influence of isentropic transport on seasonal ozone variations in the lower stratosphere and subtropical upper troposphere

NASA Technical Reports Server (NTRS)

Jing, P.; Cunnold, D. M.; Yang, E.-S.; Wang, H.-J.

2005-01-01

The isentropic cross-tropopause ozone transport has been estimated in both hemispheres in 1999 based on the potential vorticity mapping of Stratospheric Aerosol and Gas Experiment 11 ozone measurements and contour advection calculations using the NASA Goddard Space Flight Center Global and Modeling Assimilation Office analysis. The estimated net isentropic stratosphere-to-troposphere ozone flux is approx.118 +/- 61 x 10(exp9)kg/yr globally within the layer between 330 and 370 K in 1999; 60% of it is found in the Northern Hemisphere, and 40% is found in the Southern Hemisphere. The monthly average ozone fluxes are strongest in summer and weakest in winter in both hemispheres. The seasonal variations of ozone in the lower stratosphere (LS) and upper troposphere (UT) have been analyzed using ozonesonde observations from ozonesonde stations in the extratropics and subtropics, respectively. It is shown that observed ozone levels increase in the UT over subtropical ozonesonde stations and decrease in the LS over extratropical stations in late spring/early summer and that the ozone increases in the summertime subtropical UT are unlikely to be explained by photochemical ozone production and diabatic transport alone. We conclude that isentropic transport is a significant contributor to ozone levels in the subtropical upper troposphere, especially in summer.

Decadal trends in tropospheric ozone over East Asian Pacific rim during 1998-2007: Implications for emerging Asian emissions impacts and comparison to European and North American records (Invited)

NASA Astrophysics Data System (ADS)

Tanimoto, H.; Ohara, T.; Uno, I.

2010-12-01

We examine springtime ozone trends at nine remote locations in East Asian Pacific rim during the last decade (1998-2007). The observed decadal ozone trends are relatively small at surface sites but are substantially larger at a mountainous site. The level and increasing rate of ozone at the mountainous site are both higher than those observed at background sites in Europe and North America. We use a regional chemistry-transport model to explore the observed changes and how changes in Asian anthropogenic emissions have contributed to the observed increasing trends. The model with yearly-dependent regional emissions successfully reproduces the levels, variability, and interannual variations of ozone at all the surface sites. It predicts increasing trends at the mountainous site, suggesting that increasing Asian anthropogenic emissions account for about half the observed increase. However, the discrepancy between the observation and model results after 2003 (the time of largest emission increase) suggests significant underestimation of the actual growth of the Asian anthropogenic emissions and/or incompleteness in the modeling of pollution export from continental Asia. These findings imply that improving emissions inventory and transport scheme is needed to better understand rapidly evolving tropospheric ozone in East Asia and its potential climatic and environmental impacts.

Use of Ozone to Treat Ileostomy Dermatitis in an Experimental Rat Model

PubMed Central

Biçer, Şenol; Sayar, İlyas; Gürsul, Cebrail; Işık, Arda; Aydın, Merve; Peker, Kemal; Demiryilmaz, İsmail

2016-01-01

Background Dermatitis associated with ileostomy is an important problem that affects many people, especially children. The aim of this study was to investigate the therapeutic effects of ozone on dermatitis due to ileostomy, and to develop an alternative treatment option. Material/Methods A total of 28 rats were divided into 4 groups: control, ileostomy, ozone, and zinc oxide. Ileostomy was performed in all rats except the control group. After a 1-week waiting time, the ozone group was administered ozone therapy and the zinc oxide group was administered zinc oxide cream locally once a day for a total of 7 days. All rats were sacrificed at the end of this period. The efficacy of treatment was examined by biochemical, histopathological, and immunohistochemical parameters. The levels of malondialdehyde (MDA), total glutathione (tGSH), total antioxidant capacity (TAC), and total oxidant status (TOS) were measured from tissue. Vascular endothelial growth factor (VEGF) and proliferating cell nuclear antigen (PCNA) were examined immunohistochemically. Results Dermatitis occurred pathologically in all rats that underwent ileostomy surgery. The lowest dermatitis score was in the ozone treatment group (p<0.05). Ileostomy dermatitis caused increased levels of MDA and TOS. Ozone treatment resulted in reduced MDA and TOS levels, while the levels of tGSH and TAC were increased (p<0.05). Both VEGF and PCNA immunostaining were augmented in the ozone treatment group (p<0.05). Conclusions Local ozone application may be a good alternative compared to the conventional treatment methods for the prevention of skin lesions that develop after ileostomy. PMID:26947591

Interacting effects of ozone and CO2 on growth and physiological processes in northern forest trees

Treesearch

J. G. Isebrands; D. F. Karnosky

1996-01-01

Globally, surface-level concentrations of both CO2 and ozone (O3) are increasing annually. Because many studies have shown beneficial effects of increasing CO2, predictions have been made that elevated levels of CO2 would compensate for growth decreases caused by O3...

75 FR 27514 - Approval and Promulgation of Implementation Plans and Designation of Areas for Air Quality...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-17

... vehicular traffic are also subject to increased ozone levels because wind carries ozone and its precursors... ozone triggers a variety of health problems including aggravated asthma, reduced lung capacity, and... is called the design value (DV). The DV indicates the severity of the ozone problem in an area; it is...

Inflammatory and Repair Pathways Induced in Human Bronchoalveolar Lavage Cells with Ozone Inhalation

PubMed Central

Wong, Hofer; Tenney, Rachel; Chen, Chun; Stiner, Rachel; Balmes, John R.; Paquet, Agnès C.; Arjomandi, Mehrdad

2015-01-01

Background Inhalation of ambient levels of ozone causes airway inflammation and epithelial injury. Methods To examine the responses of airway cells to ozone-induced oxidative injury, 19 subjects (7 with asthma) were exposed to clean air (0ppb), medium (100ppb), and high (200ppb) ambient levels of ozone for 4h on three separate occasions in a climate-controlled chamber followed by bronchoscopy with bronchoalveolar lavage (BAL) 24h later. BAL cell mRNA expression was examined using Affymetrix GeneChip Microarray. The role of a differentially expressed gene (DEG) in epithelial injury was evaluated in an in vitro model of injury [16HBE14o- cell line scratch assay]. Results Ozone exposure caused a dose-dependent up-regulation of several biologic pathways involved in inflammation and repair including chemokine and cytokine secretion, activity, and receptor binding; metalloproteinase and endopeptidase activity; adhesion, locomotion, and migration; and cell growth and tumorigenesis regulation. Asthmatic subjects had 1.7- to 3.8-fold higher expression of many DEGs suggestive of increased proinflammatory and matrix degradation and remodeling signals. The most highly up-regulated gene was osteopontin, the protein level of which in BAL fluid increased in a dose-dependent manner after ozone exposure. Asthmatic subjects had a disproportionate increase in non-polymerized osteopontin with increasing exposure to ozone. Treatment with polymeric, but not monomeric, osteopontin enhanced the migration of epithelial cells and wound closure in an α9β1 integrin-dependent manner. Conclusions Expression profiling of BAL cells after ozone exposure reveals potential regulatory genes and pathways activated by oxidative stress. One DEG, osteopontin, promotes epithelial wound healing in an in vitro model of injury. PMID:26035830

Ozone depletion, related UVB changes and increased skin cancer incidence

NASA Astrophysics Data System (ADS)

Kane, R. P.

1998-03-01

Stratospheric ozone at middle latitudes shows a seasonal variation of about +/-20%, a quasi-biennial oscillation of 1-10% range and a long-term variation in which the level was almost steady up to about 1979 and declined thereafter to the present day by about 10%. These variations are expected to be reflected in solar UVB observed at the ground, but in an opposite direction. Thus UVB should have had a long-term increase of about 10-20%, which should cause an increase in skin cancer incidence of about 20-40%. Skin cancer incidence has increased all over the world, e.g. about 90% in USA during 1974-1990. It is popularly believed that this increase in skin cancer incidence is related to the recent ozone depletion. This seems to be incorrect, for two reasons. Firstly, the observed skin cancer increase is too large (90%) compared with the expected value (40%) from ozone depletion. Secondly, cancer does not develop immediately after exposure to solar UVB. The sunburns may occur within hours; but cancer development and detection may take years, even decades. Hence the observed skin cancer increase since 1974 (no data available for earlier periods) must have occurred due to exposure to solar UVB in the 1950s and 1960s, when there was no ozone depletion. Thus, the skin cancer increase must be attributed to harmful solar UVB levels existing even in the 1960s, accentuated later not by ozone depletion (which started only much later, by 1979) but by other causes, such as a longer human life span, better screening, increasing tendencies of sunbathing at beaches, etc., in affluent societies. On the other hand, the recent ozone depletion and the associated UVB increases will certainly take their toll; only that the effects will not be noticed now but years or decades from now. The concern for the future expressed in the Montreal Protocol for reducing ozone depletion by controlling CFC production is certainly justified, especially because increased UVB is harmful to animal and plant life also. However, because the increased cancer incidence observed so far may not be (entirely) due to ozone depletion, other causes need to be investigated urgently and, if possible, remedied. Otherwise, deaths due to skin cancer will continue even after CFC production is controlled and ozone levels are recovered. There is no room for complacency. If nothing else is possible, use of protective screens and creams and avoiding exposure to sunlight during peak hours (10:00-15:00 h) should be strongly recommended.

Profiling secondary metabolites of needles of ozone-fumigated white pine (Pinus strobus) clones by thermally assisted hydrolysis/methylation GC/MS.

PubMed

Shadkami, F; Helleur, R J; Cox, R M

2007-07-01

Plant secondary metabolites have an important role in defense responses against herbivores and pathogens, and as a chemical barrier to elevated levels of harmful air pollutants. This study involves the rapid chemical profiling of phenolic and diterpene resin acids in needles of two (ozone-tolerant and ozone-sensitive) white pine (Pinus strobus) clones, fumigated with different ozone levels (control, and daily events peaking at 80 and 200 ppb) for 40 days. The phenolic and resin acids were measured using thermally assisted hydrolysis and methylation (THM) gas chromatography/mass spectrometry. Short-term fumigation affected the levels of two phenolic acids, i.e., 3-hydroxybenzoic and 3,4-dihydroxybenzoic acids, in that both showed a substantial decrease in concentration with increased ozone dose. The decrease in concentration of these THM products may be caused by inhibition of the plant's shikimate biochemical pathway caused by ozone exposure. The combined occurrence of these two ozone-sensitive indicators has a role in biomonitoring of ozone levels and its impact on forest productivity. In addition, chromatographic profile differences in the major diterpene resin acid components were observed between ozone-tolerant and ozone-sensitive clones. The resin acids anticopalic, 3-oxoanticopalic, 3beta-hydroxyanticopalic, and 3,4-cycloanticopalic acids were present in the ozone-sensitive pine; however, only anticopalic acid was present in the ozone-tolerant clone. This phenotypic variation in resin acid composition may be useful in distinguishing populations that are differentially adapted to air pollutants.

[Effects of elevated ozone concentrations on reactive oxygen metabolism and related gene expression in Ginkgo biloba leaves].

PubMed

Ruan, Ya Nan; Xu, Sheng; Guo, Long; Zhu, Ming Zhu; Wang, Cong; Li, Shu Yuan; Wang, Hong Yan

2017-11-01

By using the open top chambers (OTCs) fumigation method, this paper investigated the changes of foliar injury, level of reactive oxygen species (ROS), activities and gene expression of antioxidant enzymes in Ginkgo biloba leaves under different ozone (ambient ozone≈40, 80, 160, 200 nmol·mol -1 ) concentrations, in order to study the effects of elevated ozone (O 3 ) concentrations on reactive metabolism. The results showed that the obvious foliar injuries were observed in 160 and 200 nmol·mol -1 O 3 treatments, while no visible injury was observed in 80 nmol·mol -1 O 3 and ambient O 3 treatments. After 20 d, a significant increase in O 2 -· generation rate was observed in G. biloba leaves exposed to 160, 200 nmol·mol -1 O 3 , compared with ambient ozone and 80 nmol·mol -1 O 3 , and there were no significant differences between ambient O 3 and 80 nmol·mol -1 treatments. After 40 d, H 2 O 2 content of G. biloba leaves in 160 and 200 nmol·mol -1 O 3 was significantly higher than that in 80 nmol·mol -1 and ambient ozone, respectively. The activities of catalase (CAT) in 160 and 200 nmol·mol -1 treatments were also significantly higher than that in 80 nmol·mol -1 and ambient O 3 treatments. The ascorbate peroxidase (APX) activity of leaves for each elevated O 3 treatment was lower than that of ambient ozone. The level of CAT and APX expression increased progressively after 40 d O 3 treatment. The expression intensity of GbD was conspicuously strengthened along with the increase of ozone concentration and fumigation time. Le-vel of reactive oxygen increased, activities of antioxidant enzyme decreased, level of gene expression down-regulated, and foliar visible injury was observed in leaves of G. biloba in elevated ozone stress.

Growth of soybean at future tropospheric ozone concentrations decreases canopy evapotranspiration and soil water depletion.

PubMed

Bernacchi, Carl J; Leakey, Andrew D B; Kimball, Bruce A; Ort, Donald R

2011-06-01

Tropospheric ozone is increasing in many agricultural regions resulting in decreased stomatal conductance and overall biomass of sensitive crop species. These physiological effects of ozone forecast changes in evapotranspiration and thus in the terrestrial hydrological cycle, particularly in intercontinental interiors. Soybean plots were fumigated with ozone to achieve concentrations above ambient levels over five growing seasons in open-air field conditions. Mean season increases in ozone concentrations ([O₃]) varied between growing seasons from 22 to 37% above background concentrations. The objective of this experiment was to examine the effects of future [O₃] on crop ecosystem energy fluxes and water use. Elevated [O₃] caused decreases in canopy evapotranspiration resulting in decreased water use by as much as 15% in high ozone years and decreased soil water removal. In addition, ozone treatment resulted in increased sensible heat flux in all years indicative of day-time increase in canopy temperature of up to 0.7 °C. Published by Elsevier Ltd.

Ozone response to a CO2 doubling - Results from a stratospheric circulation model with heterogeneous chemistry

NASA Technical Reports Server (NTRS)

Pitari, G.; Palermi, S.; Visconti, G.; Prinn, R. G.

1992-01-01

A spectral 3D model of the stratosphere has been used to study the sensitivity of polar ozone with respect to a carbon dioxide increase. The lower stratospheric cooling associated with an imposed CO2 doubling may increase the probability of polar stratospheric cloud (PSC) formation and this affect ozone. The ozone perturbation obtained with the inclusion of a simple parameterization for heterogeneous chemistry on PSCs is compared to that relative to a pure homogeneous chemistry. In both cases the temperature perturbation is determined by a CO2 doubling, while the total chlorine content is kept at the present level. It is shown that the lower temperature may increase the depth and the extension of the ozone hole by extending the area amenable to PSC formation. It may be argued that this effect, coupled with an increasing amount of chlorine, may produce a positive feedback on the ozone destruction.

Ozone sensitivity in hybrid poplar correlates with insensitivity to both salicylic acid and jasmonic acid. The role of programmed cell death in lesion formation.

PubMed

Koch, J R; Creelman, R A; Eshita, S M; Seskar, M; Mullet, J E; Davis, K R

2000-06-01

Our earlier studies demonstrated that the ozone-sensitive hybrid poplar clone NE-388 displays an attenuated level of ozone-, wound-, and phytopathogen-induced defense gene expression. To determine if this reduced gene activation involves signal transduction pathways dependent on salicylic acid (SA) and/or jasmonic acid (JA), we compared the responses of NE-388 and an ozone-tolerant clone, NE-245, to these signal molecules. JA levels increased in both clones in response to ozone, but only minimal increases in SA levels were measured for either clone. Treatment with SA and methyl jasmonate induced defense gene expression only in NE-245, indicating that NE-388 is insensitive to these signal molecules. DNA fragmentation, an indicator of programmed cell death (PCD), was detected in NE-245 treated with either ozone or an avirulent phytopathogen, but was not detected in NE-388. We conclude that these clones undergo two distinct mechanisms of ozone-induced lesion formation. In NE-388, lesions appear to be due to toxic cell death resulting from a limited ability to perceive and subsequently activate SA- and/or JA-mediated antioxidant defense responses. In NE-245, SA-dependent PCD precedes lesion formation via a process related to the PCD pathway activated by phytopathogenic bacteria. These results support the hypothesis that ozone triggers a hypersensitive response.

Ozone Sensitivity in Hybrid Poplar Correlates with Insensitivity to Both Salicylic Acid and Jasmonic Acid. The Role of Programmed Cell Death in Lesion Formation1

PubMed Central

Koch, Jennifer Riehl; Creelman, Robert A.; Eshita, Steven M.; Seskar, Mirjana; Mullet, John E.; Davis, Keith R.

2000-01-01

Our earlier studies demonstrated that the ozone-sensitive hybrid poplar clone NE-388 displays an attenuated level of ozone-, wound-, and phytopathogen-induced defense gene expression. To determine if this reduced gene activation involves signal transduction pathways dependent on salicylic acid (SA) and/or jasmonic acid (JA), we compared the responses of NE-388 and an ozone-tolerant clone, NE-245, to these signal molecules. JA levels increased in both clones in response to ozone, but only minimal increases in SA levels were measured for either clone. Treatment with SA and methyl jasmonate induced defense gene expression only in NE-245, indicating that NE-388 is insensitive to these signal molecules. DNA fragmentation, an indicator of programmed cell death (PCD), was detected in NE-245 treated with either ozone or an avirulent phytopathogen, but was not detected in NE-388. We conclude that these clones undergo two distinct mechanisms of ozone-induced lesion formation. In NE-388, lesions appear to be due to toxic cell death resulting from a limited ability to perceive and subsequently activate SA- and/or JA-mediated antioxidant defense responses. In NE-245, SA-dependent PCD precedes lesion formation via a process related to the PCD pathway activated by phytopathogenic bacteria. These results support the hypothesis that ozone triggers a hypersensitive response. PMID:10859179

Development of a comprehensive air quality modeling framework for a coastal urban airshed in south Texas

NASA Astrophysics Data System (ADS)

Farooqui, Mohmmed Zuber

Tropospheric ozone is one of the major air pollution problems affecting urban areas of United States as well as other countries in the world. Analysis of surface observed ozone levels in south and central Texas revealed several days exceeding 8-hour average ozone National Ambient of Air Quality Standards (NAAQS) over the past decade. Two major high ozone episodes were identified during September of 1999 and 2002. A photochemical modeling framework for the high ozone episodes in 1999 and 2002 were developed for the Corpus Christi urban airshed. The photochemical model was evaluated as per U.S. Environmental Protection Agency (EPA) recommended statistical methods and the models performed within the limits set by EPA. An emission impact assessment of various sources within the urban airshed was conducted using the modeling framework. It was noted that by nudging MM5 with surface observed meteorological parameters and sea-surface temperature, the coastal meteorological predictions improved. Consequently, refined meteorology helped the photochemical model to better predict peak ozone levels in urban airsheds along the coastal margins of Texas including in Corpus Christi. The emissions assessment analysis revealed that Austin and San Antonio areas were significantly affected by on-road mobile emissions from light-duty gasoline and heavy-duty diesel vehicles. The urban areas of San Antonio, Austin, and Victoria areas were estimated to be NOx sensitive. Victoria was heavily influenced by point sources in the region while Corpus Christi was influenced by both point and non-road mobile sources and was identified to be sensitive to VOC emissions. A rise in atmospheric temperature due to climate change potentially increase ozone exceedances and the peak ozone levels within the study region and this will be a major concern for air quality planners. This study noted that any future increase in ambient temperature would result in a significant increase in the urban and regional ozone levels within the modeling domain and it would also enhance the transported levels of ozone across the region. Overall, the photochemical modeling framework helped in evaluating the impact of various parameters affecting ozone air quality; and, it has the potential to be a tool for policy-makers to develop effective emissions control strategies under various regulatory and climate conditions.

Atmospheric carbon dioxide and chlorofluoromethanes - Combined effects on stratospheric ozone, temperature, and surface temperature

NASA Technical Reports Server (NTRS)

Callis, L. B.; Natarajan, M.

1981-01-01

The effects of combined CO2 and CFCl3 and CF2Cl2 time-dependent scenarios on atmospheric O3 and temperature are described; the steady-state levels of O3 and surface temperature, to which the chlorofluoromethane scenario tends in the presence of twice and four time ambient CO2, are examined; and surface temperature changes, caused by the combined effects, are established. A description of the model and of the experiments is presented. Results indicate that (1) the total ozone time history is significantly different from that due to the chlorofluoromethane alone; (2) a local ozone minimum occurs in the upper stratosphere about 45 years from the present with a subsequent ozone increase, then decline; and (3) steady-state solutions indicate that tropospheric temperature and water vapor increases, associated with increased infrared opacity, cause significant changes in tropospheric ozone levels for 2 x CO2 and 4 x CO2, without the addition of chlorofluoromethanes.

Impact of volcanic aerosols on stratospheric ozone recovery

NASA Astrophysics Data System (ADS)

Naik, Vaishali; Horowitz, Larry W.; Daniel Schwarzkopf, M.; Lin, Meiyun

2017-09-01

We use transient GFDL-CM3 chemistry-climate model simulations over the 2006-2100 period to show how the influence of volcanic aerosols on the extent and timing of ozone recovery varies with (a) future greenhouse gas scenarios (Representative Concentration Pathway (RCP)4.5 and RCP8.5) and (b) halogen loading. Current understanding is that elevated volcanic aerosols reduce ozone under high halogen loading but increase ozone under low halogen loading when the chemistry is more NOx dominated. With extremely low aerosol loadings (designated here as "background"), global stratospheric ozone burden is simulated to return to 1980 levels around 2050 in the RCP8.5 scenario but remains below 1980 levels throughout the 21st century in the RCP4.5 scenario. In contrast, with elevated volcanic aerosols, ozone column recovers more quickly to 1980 levels, with recovery dates ranging from the mid-2040s in RCP8.5 to the mid-2050s to early 2070s in RCP4.5. The ozone response in both future emission scenarios increases with enhanced volcanic aerosols. By 2100, the 1980 baseline-adjusted global stratospheric ozone column is projected to be 20-40% greater in RCP8.5 and 110-200% greater in RCP4.5 with elevated volcanic aerosols compared to simulations with the extremely low background aerosols. The weaker ozone enhancement at 2100 in RCP8.5 than in RCP4.5 in response to elevated volcanic aerosols is due to a factor of 2.5 greater methane in RCP8.5 compared with RCP4.5. Our results demonstrate the substantial uncertainties in stratospheric ozone projections and expected recovery dates induced by volcanic aerosol perturbations that need to be considered in future model ozone projections.

Climate Change and Air Pollution-Related Health Impacts in the United States: Assessment of Current Findings

NASA Astrophysics Data System (ADS)

Kinney, P.; Fann, N.

2016-12-01

Ambient air pollution can be affected by climate in a variety of ways, which in turn have important implications for human health. Observed and projected changes in climate lead to modified weather pat­terns and biogenic emissions, which influence the levels and geographic patterns of outdoor air pollutants of health concern, including ground-level ozone (O3) and fine particulate matter (PM2.5). The USGCRP scientific assessment of the human health impacts of climate change concluded with high confidence that climate change will make it harder for any given regulatory approach to reduce ground-level ozone pollution in the future as meteorological conditions become increasingly conducive to forming ozone over most of the United States. Unless offset by additional emissions reductions of ozone precursors, these climate-driven increases in ozone will cause premature deaths, hospital visits, lost school days, and acute respiratory symptoms. The evidence for climate impacts on PM2.5 is less robust than that for ozone. However, one mechanism through which climate change is likely to affect PM2.5 as well as O3 in the United States is via impacts on wildfires. Wildfires emit precursors of both fine particles and O3, which increase the risk of premature death and adverse chronic and acute cardiovascular and respiratory health outcomes. Climate change is projected to increase the number and severity of naturally occurring wildfires in parts of the United States, increasing emissions of particulate matter and ozone precursors and resulting in additional adverse health outcomes. We present the key results and conclusions from a nationwide assessment of O3 health impacts in 2030, as well as new evidence for respiratory health effects of wildfires in the western United States.

High Wintertime Ozone in the Uinta Basin: Diurnal Mixing and Ozone Production Measured by Tethered Ozonesondes

NASA Astrophysics Data System (ADS)

Johnson, B.; Cullis, P.; Schnell, R. C.; Oltmans, S. J.; Sterling, C. W.; Jordan, A. F.; Hall, E.

2016-12-01

Extreme high ozone mixing ratios, far exceeding U.S. National Air Quality Standards, were observed in the Uinta Basin in January-February 2013 under conditions highly favorable for wintertime ozone production. Hourly average ozone mixing ratios increased from regional background levels of 40-50 ppbv to >160 ppbv during several multi-day episodes of prolonged temperature inversions over snow-covered ground within air confining topography. Extensive surface and tethered balloon profile measurements of ozone, meteorology, CH4, CO2, NO2 and a suite of non-methane hydrocarbons (NMHCs) link emissions from oil and natural gas extraction with the strong ozone production throughout the Basin. High levels of NMHCs that were well correlated with CH4 showed that abundant O3 precursors were available throughout the Basin where high ozone mixing ratios extended from the surface to the top of the inversion layer at 200 m above ground level. This layer was at a nearly uniform height across the Basin even though there are significant terrain variations. Tethered balloon measurements rising above the elevated levels of ozone within the cold pool layer beneath the inversion measured regional background O3 concentrations. Surface wind and direction data from tethered balloons showed a consistent diurnal pattern in the Basin that moved air with the highest levels of CH4 and ozone precursor NMHC's from the gas fields of the east-central portion of the Basin to the edges during the day, before draining back into the Basin at night.

Ozone pollution in China: A review of concentrations, meteorological influences, chemical precursors, and effects.

PubMed

Wang, Tao; Xue, Likun; Brimblecombe, Peter; Lam, Yun Fat; Li, Li; Zhang, Li

2017-01-01

High concentrations of ozone in urban and industrial regions worldwide have long been a major air quality issue. With the rapid increase in fossil fuel consumption in China over the past three decades, the emission of chemical precursors to ozone-nitrogen oxides and volatile organic compounds-has increased sharply, surpassing that of North America and Europe and raising concerns about worsening ozone pollution in China. Historically, research and control have prioritized acid rain, particulate matter, and more recently fine particulate matter (PM 2.5 ). In contrast, less is known about ozone pollution, partly due to a lack of monitoring of atmospheric ozone and its precursors until recently. This review summarizes the main findings from published papers on the characteristics and sources and processes of ozone and ozone precursors in the boundary layer of urban and rural areas of China, including concentration levels, seasonal variation, meteorology conducive to photochemistry and pollution transport, key production and loss processes, ozone dependence on nitrogen oxides and volatile organic compounds, and the effects of ozone on crops and human health. Ozone concentrations exceeding the ambient air quality standard by 100-200% have been observed in China's major urban centers such as Jing-Jin-Ji, the Yangtze River delta, and the Pearl River delta, and limited studies suggest harmful effect of ozone on human health and agricultural corps; key chemical precursors and meteorological conditions conductive to ozone pollution have been investigated, and inter-city/region transport of ozone is significant. Several recommendations are given for future research and policy development on ground-level ozone. Copyright © 2016 Elsevier B.V. All rights reserved.

Association of Ozone Exposure With Cardiorespiratory Pathophysiologic Mechanisms in Healthy Adults.

PubMed

Day, Drew B; Xiang, Jianbang; Mo, Jinhan; Li, Feng; Chung, Mingkei; Gong, Jicheng; Weschler, Charles J; Ohman-Strickland, Pamela A; Sundell, Jan; Weng, Wenguo; Zhang, Yinping; Zhang, Junfeng Jim

2017-09-01

Exposure to ozone has been associated with cardiovascular mortality, but the underlying biological mechanisms are not yet understood. To examine the association between ozone exposure and cardiopulmonary pathophysiologic mechanisms. A longitudinal study involving 89 healthy adult participants living on a work campus in Changsha City, China, was conducted from December 1, 2014, to January 31, 2015. This unique quasiexperimental setting allowed for better characterization of air pollutant exposure effects because the participants spent most of their time in controlled indoor environments. Concentrations of indoor and outdoor ozone, along with the copollutants particulate matter, nitrogen dioxide, and sulfur dioxide, were monitored throughout the study period and then combined with time-activity information and filtration conditions of each residence and office to estimate 24-hour and 2-week combined indoor and outdoor mean exposure concentrations. Associations between each exposure measure and outcome measure were analyzed using single-pollutant and 2-pollutant linear mixed models controlling for ambient temperature, secondhand smoke exposure, and personal-level time-varying covariates. Biomarkers indicative of inflammation and oxidative stress, arterial stiffness, blood pressure, thrombotic factors, and spirometry were measured at 4 sessions. Of the 89 participants, 25 (28%) were women and the mean (SD) age was 31.5 (7.6) years. The 24-hour ozone exposure concentrations ranged from 1.4 to 19.4 parts per billion (ppb), corresponding to outdoor concentrations ranging from 4.3 to 47.9 ppb. Within this range, in models controlling for a second copollutant and other potential confounders, a 10-ppb increase in 24-hour ozone was associated with mean increases of 36.3% (95% CI, 29.9%-43.0%) in the level of platelet activation marker soluble P-selectin, 2.8% (95% CI, 0.6%-5.1%) in diastolic blood pressure, 18.1% (95% CI, 4.5%-33.5%) in pulmonary inflammation markers fractional exhaled nitric oxide, and 31.0% (95% CI, 0.2%-71.1%) in exhaled breath condensate nitrite and nitrate as well as a -9.5% (95% CI, -17.7% to -1.4%) decrease in arterial stiffness marker augmentation index. A 10-ppb increase in 2-week ozone was associated with increases of 61.1% (95% CI, 37.8%-88.2%) in soluble P-selectin level and 126.2% (95% CI, 12.1%-356.2%) in exhaled breath condensate nitrite and nitrate level. Other measured biomarkers, including spirometry, showed no significant associations with either 24-hour ozone or 2-week ozone exposures. Short-term ozone exposure at levels not associated with lung function changes was associated with platelet activation and blood pressure increases, suggesting a possible mechanism by which ozone may affect cardiovascular health.

Impact of shipping emissions on ozone levels over Europe: assessing the relative importance of the Standard Nomenclature for Air Pollution (SNAP) categories.

PubMed

Tagaris, Efthimios; Stergiou, Ioannis; Sotiropoulou, Rafaella-Eleni P

2017-06-01

The impact of shipping emissions on ozone mixing ratio over Europe is assessed for July 2006 using the Community Multiscale Air Quality modeling system and the Netherlands Organization for Applied Scientific Research anthropogenic emission inventory. Results suggest that ship-induced ozone contribution to the total surface ozone exceeds 5% over the sea and near the coastline, while an increase up to 5% is simulated over a large portion of the European land. The largest impact (i.e., an increase up to 30%) is simulated over the Mediterranean Sea. In addition, shipping emissions are simulated to increase NO 2 mixing ratio more than 90%, locally, and to modify the oxidizing capacity of the atmosphere through hydroxyl radical formation (increase by 20-60% over the sea along the European coasts and near the coastal zone). Therefore, emissions from ships may counteract the benefits derived from the anthropogenic emissions reduction strategies over the continent. Simulations suggest regions where shipping emissions have a major impact on ozone mixing ratio compared to individual anthropogenic emission sector categories. Shipping emissions are estimated to play an important role on ozone levels compared to road transport sector near the coastal zone. The impact of shipping emissions on ozone formation is also profound over a great part of the European land compared to the rest of anthropogenic emission categories.

Ozone depletion following future volcanic eruptions

NASA Astrophysics Data System (ADS)

Eric Klobas, J.; Wilmouth, David M.; Weisenstein, Debra K.; Anderson, James G.; Salawitch, Ross J.

2017-07-01

While explosive volcanic eruptions cause ozone loss in the current atmosphere due to an enhancement in the availability of reactive chlorine following the stratospheric injection of sulfur, future eruptions are expected to increase total column ozone as halogen loading approaches preindustrial levels. The timing of this shift in the impact of major volcanic eruptions on the thickness of the ozone layer is poorly known. Modeling four possible climate futures, we show that scenarios with the smallest increase in greenhouse gas concentrations lead to the greatest risk to ozone from heterogeneous chemical processing following future eruptions. We also show that the presence in the stratosphere of bromine from natural, very short-lived biogenic compounds is critically important for determining whether future eruptions will lead to ozone depletion. If volcanic eruptions inject hydrogen halides into the stratosphere, an effect not considered in current ozone assessments, potentially profound reductions in column ozone would result.

Ozone exposure of a weed community produces adaptive changes in seed populations of Spergula arvensis.

PubMed

Landesmann, Jennifer B; Gundel, Pedro E; Martínez-Ghersa, M Alejandra; Ghersa, Claudio M

2013-01-01

Tropospheric ozone is one of the major drivers of global change. This stress factor alters plant growth and development. Ozone could act as a selection pressure on species communities composition, but also on population genetic background, thus affecting life history traits. Our objective was to evaluate the consequences of prolonged ozone exposure of a weed community on phenotypic traits of Spergulaarvensis linked to persistence. Specifically, we predicted that the selection pressure exerted by high ozone concentrations as well as the concomitant changes in the weed community would drive population adaptive changes which will be reflected on seed germination, dormancy and longevity. In order to test seed viability and dormancy level, we conducted germination experiments for which we used seeds produced by S. arvensis plants grown within a weed community exposed to three ozone treatments during four years (0, 90 and 120 ppb). We also performed a soil seed bank experiment to test seed longevity with seeds coming from both the four-year ozone exposure experiment and from a short-term treatment conducted at ambient and added ozone concentrations. We found that prolonged ozone exposure produced changes in seed germination, dormancy and longevity, resulting in three S. arvensis populations. Seeds from the 90 ppb ozone selection treatment had the highest level of germination when stored at 75% RH and 25 °C and then scarified. These seeds showed the lowest dormancy level when being subjected to 5 ºC/5% RH and 25 ºC/75% followed by 5% RH storage conditions. Furthermore, ozone exposure increased seed persistence in the soil through a maternal effect. Given that tropospheric ozone is an important pollutant in rural areas, changes in seed traits due to ozone exposure could increase weed persistence in fields, thus affecting weed-crop interactions, which could ultimately reduce crop production.

Ozone Exposure of a Weed Community Produces Adaptive Changes in Seed Populations of Spergula arvensis

PubMed Central

Landesmann, Jennifer B.; Gundel, Pedro E.; Martínez-Ghersa, M. Alejandra; Ghersa, Claudio M.

2013-01-01

Tropospheric ozone is one of the major drivers of global change. This stress factor alters plant growth and development. Ozone could act as a selection pressure on species communities composition, but also on population genetic background, thus affecting life history traits. Our objective was to evaluate the consequences of prolonged ozone exposure of a weed community on phenotypic traits of Spergula arvensis linked to persistence. Specifically, we predicted that the selection pressure exerted by high ozone concentrations as well as the concomitant changes in the weed community would drive population adaptive changes which will be reflected on seed germination, dormancy and longevity. In order to test seed viability and dormancy level, we conducted germination experiments for which we used seeds produced by S. arvensis plants grown within a weed community exposed to three ozone treatments during four years (0, 90 and 120 ppb). We also performed a soil seed bank experiment to test seed longevity with seeds coming from both the four-year ozone exposure experiment and from a short-term treatment conducted at ambient and added ozone concentrations. We found that prolonged ozone exposure produced changes in seed germination, dormancy and longevity, resulting in three S. arvensis populations. Seeds from the 90 ppb ozone selection treatment had the highest level of germination when stored at 75% RH and 25 °C and then scarified. These seeds showed the lowest dormancy level when being subjected to 5 ºC/5% RH and 25 ºC/75% followed by 5% RH storage conditions. Furthermore, ozone exposure increased seed persistence in the soil through a maternal effect. Given that tropospheric ozone is an important pollutant in rural areas, changes in seed traits due to ozone exposure could increase weed persistence in fields, thus affecting weed-crop interactions, which could ultimately reduce crop production. PMID:24086640

Oxidative stress-dependent changes in immune responses and cell death in the substantia nigra after ozone exposure in rat.

PubMed

Rivas-Arancibia, Selva; Zimbrón, Luis Fernando Hernández; Rodríguez-Martínez, Erika; Maldonado, Perla D; Borgonio Pérez, Gabino; Sepúlveda-Parada, María

2015-01-01

Parkinson's disease has been associated with the selective loss of neurons in the substantia nigra pars compacta. Increasing evidence suggests that oxidative stress plays a major role. The resulting increase in reactive oxygen species triggers a sequence of events that leads to cell damage, activation of microglia cells and neuroinflammatory responses. Our objective was to study whether chronic exposure to low doses of ozone, which produces oxidative stress itself, induces progressive cell death in conjunction with glial alterations in the substantia nigra. Animals were exposed to an ozone-free air stream (control) or to low doses of ozone for 7, 15, 30, 60, or 90 days. Each group underwent (1) spectrophotometric analysis for protein oxidation; (2) western blot testing for microglia reactivity and nuclear factor kappa B expression levels; and (3) immunohistochemistry for cytochrome c, GFAP, Iba-1, NFkB, and COX-2. Our results indicate that ozone induces an increase in protein oxidation levels, changes in activated astrocytes and microglia, and cell death. NFkB and cytochrome c showed an increase until 30 days of exposure, while cyclooxygenase 2 in the substantia nigra increased from 7 days up to 90 days of repetitive ozone exposure. These results suggest that oxidative stress caused by ozone exposure induces changes in inflammatory responses and progressive cell death in the substantia nigra in rats, which could also be occurring in Parkinson's disease.

Oxidative stress-dependent changes in immune responses and cell death in the substantia nigra after ozone exposure in rat

PubMed Central

Rivas-Arancibia, Selva; Zimbrón, Luis Fernando Hernández; Rodríguez-Martínez, Erika; Maldonado, Perla D.; Borgonio Pérez, Gabino; Sepúlveda-Parada, María

2015-01-01

Parkinson's disease has been associated with the selective loss of neurons in the substantia nigra pars compacta. Increasing evidence suggests that oxidative stress plays a major role. The resulting increase in reactive oxygen species triggers a sequence of events that leads to cell damage, activation of microglia cells and neuroinflammatory responses. Our objective was to study whether chronic exposure to low doses of ozone, which produces oxidative stress itself, induces progressive cell death in conjunction with glial alterations in the substantia nigra. Animals were exposed to an ozone-free air stream (control) or to low doses of ozone for 7, 15, 30, 60, or 90 days. Each group underwent (1) spectrophotometric analysis for protein oxidation; (2) western blot testing for microglia reactivity and nuclear factor kappa B expression levels; and (3) immunohistochemistry for cytochrome c, GFAP, Iba-1, NFkB, and COX-2. Our results indicate that ozone induces an increase in protein oxidation levels, changes in activated astrocytes and microglia, and cell death. NFkB and cytochrome c showed an increase until 30 days of exposure, while cyclooxygenase 2 in the substantia nigra increased from 7 days up to 90 days of repetitive ozone exposure. These results suggest that oxidative stress caused by ozone exposure induces changes in inflammatory responses and progressive cell death in the substantia nigra in rats, which could also be occurring in Parkinson's disease. PMID:25999851

The effects of greenhouse gases on the Antarctic ozone hole in the past, present, and future

NASA Astrophysics Data System (ADS)

Newman, P. A.; Li, F.; Lait, L. R.; Oman, L.

2017-12-01

The Antarctic ozone hole is primarily caused by human-produced ozone depleting substances such as chlorine-containing chlorofluorocarbons (CFCs) and bromine-containing halons. The large ozone spring-time depletion relies on the very-cold conditions of the Antarctic lower stratosphere, and the general containment of air by the polar night jet over Antarctica. Here we show the Goddard Earth Observing System Chemistry Climate Model (GEOSCCM) coupled ocean-atmosphere-chemistry model for exploring the impact of increasing greenhouse gases (GHGs). Model simulations covering the 1960-2010 period are shown for: 1) a control ensemble with observed levels of ODSs and GHGs, 2) an ensemble with fixed 1960 GHG concentrations, and 3) an ensemble with fixed 1960 ODS levels. We look at a similar set of simulations (control, 2005 fixed GHG levels, and 2005 fixed ODS levels) with a new version of GEOSCCM over the period 2005-2100. These future simulations show that the decrease of ODSs leads to similar ozone recovery for both the control run and the fixed GHG scenarios, in spite of GHG forced changes to stratospheric ozone levels. These simulations demonstrate that GHG levels will have major impacts on the stratosphere by 2100, but have only small impacts on the Antarctic ozone hole.

California Baseline Ozone Transport Study (CABOTS): Ozonesonde Measurements

NASA Astrophysics Data System (ADS)

Eiserloh, A. J., Jr.; Chiao, S.; Spitze, J.; Cauley, S.; Clark, J.; Roberts, M.

2016-12-01

Because the EPA recently lowered the ambient air quality standard for the 8-hr average of ozone (O3) to70 ppbv, California must continue to achieve significant reductions in ozone precursor emissions and prepare for new State Implementation Plans (SIP) to demonstrate how ground-level ambient ozone will be reduced below the new health-based standard. Prior studies suggest that background levels of ozone traveling across the Pacific Ocean can significantly influence surface ozone throughout California, particularly during the spring. Evidence has been presented indicating that background levels of ozone continue to increase in the western United States over the recent few decades, implying more ozone exceedances in the future. To better understand the contributions of the external natural and anthropogenic pollution sources as well as atmospheric processes for surface ozone concentrations in California during the spring and summer months, the California Baseline Ozone Transport Study (CABOTS) has been established. One major goal of CABOTS is to implement near daily ozonesonde measurements along the California Coast to quantify background ozone aloft before entering the State during high ozone season. CABOTS has been ongoing from May through August of 2016 launching ozonesondes from Bodega Bay and Half Moon Bay, California. The temporal progression of ozonesonde measurements and subsequent analysis of the data will be discussed with a focus on the contribution of background ozone to surface ozone sites inland as well as likely origins of layers aloft. Comparisons of current ozonesondes versus prior ozonesonde studies of California will also be performed. A few selected cases of high ozone layers moving onshore from different sources will be discussed as well.

Growth of soybean at midcentury tropospheric ozone concentrations decreases canopy evapotranspiration and soil water depletion

USDA-ARS?s Scientific Manuscript database

Ground-level concentrations of ozone are increasing as a result of anthropogenic activities. This is having a negative impact on terrestrial ecosystems around the planet, including agricultural ecosystems. Critical questions surround the impact of rising ozone on soybean (Glycine max) since this spe...

Airborne and ground-based observations of a weekend effect in ozone, precursors, and oxidation products in the California South Coast Air Basin

NASA Astrophysics Data System (ADS)

Pollack, I. B.; Ryerson, T. B.; Trainer, M.; Parrish, D. D.; Andrews, A. E.; Atlas, E. L.; Blake, D. R.; Brown, S. S.; Commane, R.; Daube, B. C.; Gouw, J. A.; Dubé, W. P.; Flynn, J.; Frost, G. J.; Gilman, J. B.; Grossberg, N.; Holloway, J. S.; Kofler, J.; Kort, E. A.; Kuster, W. C.; Lang, P. M.; Lefer, B.; Lueb, R. A.; Neuman, J. A.; Nowak, J. B.; Novelli, P. C.; Peischl, J.; Perring, A. E.; Roberts, J. M.; Santoni, G.; Schwarz, J. P.; Spackman, J. R.; Wagner, N. L.; Warneke, C.; Washenfelder, R. A.; Wofsy, S. C.; Xiang, B.

2011-11-01

Airborne and ground-based measurements during the CalNex (California Research at the Nexus of Air Quality and Climate Change) field study in May/June 2010 show a weekend effect in ozone in the South Coast Air Basin (SoCAB) consistent with previous observations. The well-known and much-studied weekend ozone effect has been attributed to weekend reductions in nitrogen oxide (NOx = NO + NO2) emissions, which affect ozone levels via two processes: (1) reduced ozone loss by titration and (2) enhanced photochemical production of ozone due to an increased ratio of non-methane volatile organic compounds (VOCs) to NOx. In accord with previous assessments, the 2010 airborne and ground-based data show an average decrease in NOx of 46 ± 11% and 34 ± 4%, respectively, and an average increase in VOC/NOxratio of 48 ± 8% and 43 ± 22%, respectively, on weekends. This work extends current understanding of the weekend ozone effect in the SoCAB by identifying its major causes and quantifying their relative importance from the available CalNex data. Increased weekend production of a VOC-NOxoxidation product, peroxyacetyl nitrate, compared to a radical termination product, nitric acid, indicates a significant contribution from increased photochemical production on weekends. Weekday-to-weekend differences in the products of NOx oxidation show 45 ± 13% and 42 ± 12% more extensive photochemical processing and, when compared with odd oxygen (Ox = O3 + NO2), 51 ± 14% and 22 ± 17% greater ozone production efficiency on weekends in the airborne and ground-based data, respectively, indicating that both contribute to higher weekend ozone levels in the SoCAB.

Airborne and ground-based observations of a weekend effect in ozone, precursors, and oxidation products in the California South Coast Air Basin

NASA Astrophysics Data System (ADS)

Pollack, I. B.; Ryerson, T. B.; Trainer, M.; Parrish, D. D.; Andrews, A. E.; Atlas, E. L.; Blake, D. R.; Brown, S. S.; Commane, R.; Daube, B. C.; de Gouw, J. A.; Dubé, W. P.; Flynn, J.; Frost, G. J.; Gilman, J. B.; Grossberg, N.; Holloway, J. S.; Kofler, J.; Kort, E. A.; Kuster, W. C.; Lang, P. M.; Lefer, B.; Lueb, R. A.; Neuman, J. A.; Nowak, J. B.; Novelli, P. C.; Peischl, J.; Perring, A. E.; Roberts, J. M.; Santoni, G.; Schwarz, J. P.; Spackman, J. R.; Wagner, N. L.; Warneke, C.; Washenfelder, R. A.; Wofsy, S. C.; Xiang, B.

2012-02-01

Airborne and ground-based measurements during the CalNex (California Research at the Nexus of Air Quality and Climate Change) field study in May/June 2010 show a weekend effect in ozone in the South Coast Air Basin (SoCAB) consistent with previous observations. The well-known and much-studied weekend ozone effect has been attributed to weekend reductions in nitrogen oxide (NOx = NO + NO2) emissions, which affect ozone levels via two processes: (1) reduced ozone loss by titration and (2) enhanced photochemical production of ozone due to an increased ratio of non-methane volatile organic compounds (VOCs) to NOx. In accord with previous assessments, the 2010 airborne and ground-based data show an average decrease in NOx of 46 ± 11% and 34 ± 4%, respectively, and an average increase in VOC/NOx ratio of 48 ± 8% and 43 ± 22%, respectively, on weekends. This work extends current understanding of the weekend ozone effect in the SoCAB by identifying its major causes and quantifying their relative importance from the available CalNex data. Increased weekend production of a VOC-NOx oxidation product, peroxyacetyl nitrate, compared to a radical termination product, nitric acid, indicates a significant contribution from increased photochemical production on weekends. Weekday-to-weekend differences in the products of NOx oxidation show 45 ± 13% and 42 ± 12% more extensive photochemical processing and, when compared with odd oxygen (Ox = O3 + NO2), 51 ± 14% and 22 ± 17% greater ozone production efficiency on weekends in the airborne and ground-based data, respectively, indicating that both contribute to higher weekend ozone levels in the SoCAB.

Long-Term Exposure to Ozone and Life Expectancy in the United States, 2002 to 2008

PubMed Central

Li, Chaoyang; Balluz, Lina S.; Vaidyanathan, Ambarish; Wen, Xiao-Jun; Hao, Yongping; Qualters, Judith R.

2016-01-01

Abstract Long-term exposure to ground-level ozone is associated with increased risk of morbidity and mortality. The association remains uncertain between long-term exposure to ozone and life expectancy. We assessed the associations between seasonal mean daily 8-hour maximum (8-hr max) ozone concentrations measured during the ozone monitoring seasons and life expectancy at birth in 3109 counties of the conterminous U.S. during 2002 to 2008. We used latent class growth analysis to identify latent classes of counties that had distinct mean levels and rates of change in ozone concentrations over the 7-year period and used linear regression analysis to determine differences in life expectancy by ozone levels. We identified 3 classes of counties with distinct seasonal mean daily 8-hr max ozone concentrations and rates of change. When compared with the counties with the lowest ozone concentrations, the counties with the highest ozone concentrations had 1.7- and 1.4-year lower mean life expectancy in males and females (both P < 0.0001), respectively. The associations remained statistically significant after controlling for potential confounding effects of seasonal mean PM2.5 concentrations and other selected environmental, demographic, socio-economic, and health-related factors (both P < 0.0001). A 5 ppb higher ozone concentration was associated with 0.25 year lower life expectancy in males (95% CI: −0.30 to −0.19) and 0.21 year in females (95% CI: −0.25 to −0.17). We identified 3 classes of counties with distinct mean levels and rates of change in ozone concentrations. Our findings suggest that long-term exposure to a higher ozone concentration may be associated with a lower life expectancy. PMID:26886595

Ambient ozone and incident diabetes: A prospective analysis in a large cohort of African American women.

PubMed

Jerrett, Michael; Brook, Robert; White, Laura F; Burnett, Richard T; Yu, Jeffrey; Su, Jason; Seto, Edmund; Marshall, Julian; Palmer, Julie R; Rosenberg, Lynn; Coogan, Patricia F

2017-05-01

Ozone is a ubiquitous air pollutant with increasing concentrations in many populous regions. Toxicological studies show that ozone can cause oxidative stress and increase insulin resistance. These pathways may contribute to metabolic changes and diabetes formation. In this paper, we investigate the association between ozone and incident type 2 diabetes in a large cohort of African American women. We used Cox proportional hazards models to calculate hazard ratios (HRs) for incident type 2 diabetes associated with exposure to ozone in a cohort of 45,231 African American women living in 56 metropolitan areas across the United States. Ozone levels were estimated using the U.S. EPA Models-3/Community Multiscale Air Quality (CMAQ) predictions fused with ground measurements at a resolution of 12km for the years 2007-2008. The HR per interquartile range increment of 6.7ppb of ozone was 1.18 (95% CI 1.04-1.34) for incident diabetes in adjusted models. This association was unaltered in models that controlled for fine particulate matter with diameter <2.5μm (PM 2.5 ). Associations were modified by nitrogen dioxide (NO 2 ) levels, such that HRs for ozone levels were larger in areas of lower NO 2 . Our results provide initial evidence of a positive association between O 3 and incident diabetes in African American women. Given the ubiquity of ozone exposure and the importance of diabetes on quality of life and survival, these results may have important implications for the protection of public health. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ambient ozone and incident diabetes: A prospective analysis in a large cohort of African American women

PubMed Central

Jerrett, Michael; Brook, Robert; White, Laura F.; Burnett, Richard T.; Yu, Jeffrey; Su, Jason; Seto, Edmund; Marshall, Julian; Palmer, Julie R.; Rosenberg, Lynn; Coogan, Patricia F.

2017-01-01

Background Ozone is a ubiquitous air pollutant with increasing concentrations in many populous regions. Toxicological studies show that ozone can cause oxidative stress and increase insulin resistance. These pathways may contribute to metabolic changes and diabetes formation. In this paper, we investigate the association between ozone and incident type 2 diabetes in a large cohort of African American women. Methods We used Cox proportional hazards models to calculate hazard ratios (HRs) for incident type 2 diabetes associated with exposure to ozone in a cohort of 45,231 African American women living in 56 metropolitan areas across the United States. Ozone levels were estimated using the U.S. EPA Models-3/Community Multiscale Air Quality (CMAQ) predictions fused with ground measurements at a resolution of 12 km for the years 2007–2008. Results The HR per interquartile range increment of 6.7 ppb of ozone was 1.18 (95% CI 1.04–1.34) for incident diabetes in adjusted models. This association was unaltered in models that controlled for fine particulate matter with diameter <2.5 μ (PM2.5). Associations were modified by nitrogen dioxide (NO2) levels, such that HRs for ozone levels were larger in areas of lower NO2. Conclusions Our results provide initial evidence of a positive association between in O3 and incident diabetes African American women. Given the ubiquity of ozone exposure and the importance of diabetes on quality of life and survival, these results may have important implications for the protection of public health. PMID:28153529

THE RELATIONSHIP BETWEEN OZONE-INDUCED LUNG INJURY, ANTIOXIDANT COMPENSATION AND UNDERLYING CARDIOVASCULAR DISEASE (CVD).

EPA Science Inventory

Increased levels of oxidants and compromised compensatory response are associated with CVD susceptibility. We hypothesized that rat strains demonstrating genetic CVD will have lower levels of antioxidants and greater ozone-induced pulmonary injury relative to healthy strains. Mal...

Impact Assessment of Global Temperature Perturbations on Urban and Regional Ozone Levels in South Texas

NASA Astrophysics Data System (ADS)

Biswas, Jhumoor; John, Kuruvilla; Farooqui, Zuber

The recent Intergovernmental Panel on Climate Change report predicts significant temperature increases over the century which constitutes the pulse of climate variability in a region. A modeling study was performed to identify the potential impact of temperature perturbations on tropospheric ozone concentrations in South Texas. A future case modeling scenario which incorporates appropriate emission reduction strategies without accounting for climatic inconsistencies was used in this study. The photochemical modeling was undertaken for a high ozone episode of 13-20 September 1999, and a future modeling scenario was projected for ozone episode days in 2007 utilizing the meteorological conditions prevalent in the base year. The temperatures were increased uniformly throughout the simulation domain and through the vertical layers by 2°C, 3°C, 4°C, 5°C, and 6°C, respectively in the future year modeling case. These temperature perturbations represented the outcome of extreme climate change within the study region. Significantly large changes in peak ozone concentrations were predicted by the photochemical model. For the 6°C temperature perturbation, the greatest amplification in the maximum 8-h ozone concentrations within urban areas of the modeling domain was approximately 12 ppb. In addition, transboundary flux from major industrialized urban areas played a major role in supplementing the high ozone concentrations during the perturbed temperature scenarios. The Unites States Environmental Protection Agency (USEPA) is currently proposing stricter 8-h ozone standards. The effect of temperature perturbations on ozone exceedances based on current and potential stringent future National Ambient Air Quality Standards (NAAQS) was also studied. Temperatures had an appreciable spatial impact on the 8-h ozone exceedances with a considerable increase in spatial area exceeding the NAAQS for the 8-h ozone levels within the study region for each successive augmentation in temperature. The number of exceedances of the 8-h ozone standard increased significantly with each degree rise of temperature with the problem becoming even more acute in light of stricter future proposed standards of ozone.

Ozone dose-response relationships for spring oilseed rape and broccoli

NASA Astrophysics Data System (ADS)

De Bock, Maarten; Op de Beeck, Maarten; De Temmerman, Ludwig; Guisez, Yves; Ceulemans, Reinhart; Vandermeiren, Karine

2011-03-01

Tropospheric ozone is an important air pollutant with known detrimental effects for several crops. Ozone effects on seed yield, oil percentage, oil yield and 1000 seed weight were examined for spring oilseed rape ( Brassica napus cv. Ability). For broccoli ( Brassica oleracea L. cv. Italica cv. Monaco) the effects on fresh marketable weight and total dry weight were studied. Current ozone levels were compared with an increase of 20 and 40 ppb during 8 h per day, over the entire growing season. Oilseed rape seed yield was negatively correlated with ozone dose indices calculated from emergence until harvest. This resulted in an R2 of 0.24 and 0.26 ( p < 0.001) for the accumulated hourly O 3 exposure over a threshold of 40 ppb (AOT40) and the phytotoxic ozone dose above a threshold of 6 nmol m -2 s -1 (POD 6) respectively. Estimated critical levels, above which 5% yield reduction is expected, were 3.7 ppm h and 4.4 mmol m -2 respectively. Our results also confirm that a threshold value of 6 nmol s -1 m -2 projected leaf area, as recommended for agricultural crops (UNECE, Mills, 2004), can indeed be applied for spring oilseed rape. The reduction of oilseed rape yield showed the highest correlation with the ozone uptake during the vegetative growth stage: when only the first 47 days after emergence were used to calculate POD 6, R2 values increased up to 0.476 or even 0.545 when the first 23 days were excluded. The highest ozone treatments, corresponding to the future ambient level by 2100 (IPCC, Meehl et al., 2007), led to a reduction of approximately 30% in oilseed rape seed yield in comparison to the current ozone concentrations. Oil percentage was also significantly reduced in response to ozone ( p < 0.001). As a consequence oil yield was even more severely affected by elevated ozone exposure compared to seed yield: critical levels for oil yield dropped to 3.2 ppm h and 3.9 mmol m -2. For broccoli the applied ozone doses had no effect on yield.

High Environmental Ozone Levels Lead to Enhanced Allergenicity of Birch Pollen

PubMed Central

Beck, Isabelle; Jochner, Susanne; Gilles, Stefanie; McIntyre, Mareike; Buters, Jeroen T. M.; Schmidt-Weber, Carsten; Behrendt, Heidrun; Ring, Johannes; Menzel, Annette; Traidl-Hoffmann, Claudia

2013-01-01

Background Evidence is compelling for a positive correlation between climate change, urbanisation and prevalence of allergic sensitisation and diseases. The reason for this association is not clear to date. Some data point to a pro-allergenic effect of anthropogenic factors on susceptible individuals. Objectives To evaluate the impact of urbanisation and climate change on pollen allergenicity. Methods Catkins were sampled from birch trees from different sites across the greater area of Munich, pollen were isolated and an urbanisation index, NO2 and ozone exposure were determined. To estimate pollen allergenicity, allergen content and pollen-associated lipid mediators were measured in aqueous pollen extracts. Immune stimulatory and modulatory capacity of pollen was assessed by neutrophil migration assays and the potential of pollen to inhibit dendritic cell interleukin-12 response. In vivo allergenicity was assessed by skin prick tests. Results The study revealed ozone as a prominent environmental factor influencing the allergenicity of birch pollen. Enhanced allergenicity, as assessed in skin prick tests, was mirrored by enhanced allergen content. Beyond that, ozone induced changes in lipid composition and chemotactic and immune modulatory potential of the pollen. Higher ozone-exposed pollen was characterised by less immune modulatory but higher immune stimulatory potential. Conclusion It is likely that future climate change along with increasing urbanisation will lead to rising ozone concentrations in the next decades. Our study indicates that ozone is a crucial factor leading to clinically relevant enhanced allergenicity of birch pollen. Thus, with increasing temperatures and increasing ozone levels, also symptoms of pollen allergic patients may increase further. PMID:24278250

Diverse policy implications for future ozone and surface UV in a changing climate

NASA Astrophysics Data System (ADS)

Butler, A. H.; Daniel, J. S.; Portmann, R. W.; Ravishankara, A. R.; Young, P. J.; Fahey, D. W.; Rosenlof, K. H.

2016-06-01

Due to the success of the Montreal Protocol in limiting emissions of ozone-depleting substances, concentrations of atmospheric carbon dioxide, nitrous oxide, and methane will control the evolution of total column and stratospheric ozone by the latter half of the 21st century. As the world proceeds down the path of reducing climate forcing set forth by the 2015 Conference of the Parties to the United Nations Framework Convention on Climate Change (COP 21), a broad range of ozone changes are possible depending on future policies enacted. While decreases in tropical stratospheric ozone will likely persist regardless of the future emissions scenario, extratropical ozone could either remain weakly depleted or even increase well above historical levels, with diverse implication for ultraviolet (UV) radiation. The ozone layer’s dependence on future emissions of these gases creates a complex policy decision space for protecting humans and ecosystems, which includes unexpected options such as accepting nitrous oxide emissions in order to maintain historical column ozone and surface UV levels.

Inquiry Based Projects Using Student Ozone Measurements and the Status of Using Plants as Bio-Indicators

NASA Astrophysics Data System (ADS)

Ladd, I. H.; Fishman, J.; Pippin, M.; Sachs, S.; Skelly, J.; Chappelka, A.; Neufeld, H.; Burkey, K.

2006-05-01

Students around the world work cooperatively with their teachers and the scientific research community measuring local surface ozone levels using a hand-held optical scanner and ozone sensitive chemical strips. Through the GLOBE (Global Learning and Observations to Benefit the Environment) Program, students measuring local ozone levels are connected with the chemistry of the air they breathe and how human activity impacts air quality. Educational tools have been developed and correlated with the National Science and Mathematics Standards to facilitate integrating the study of surface ozone with core curriculum. Ozone air pollution has been identified as the major pollutant causing foliar injury to plants when they are exposed to concentrations of surface ozone. The inclusion of native and agricultural plants with measuring surface ozone provides an Earth system approach to understanding surface ozone. An implementation guide for investigating ozone induced foliar injury has been developed and field tested. The guide, Using Sensitive Plants as Bio-Indicators of Ozone Pollution, provides: the background information and protocol for implementing an "Ozone Garden" with native and agricultural plants; and, a unique opportunity to involve students in a project that will develop and increase their awareness of surface ozone air pollution and its impact on plants.

Estradiol prevents ozone-induced increases in brain lipid peroxidation and impaired social recognition memory in female rats.

PubMed

Guevara-Guzmán, R; Arriaga, V; Kendrick, K M; Bernal, C; Vega, X; Mercado-Gómez, O F; Rivas-Arancibia, S

2009-03-31

There is increasing concern about the neurodegenerative and behavioral consequences of ozone pollution in industrialized urban centers throughout the world and that women may be more susceptible to brain neurodegenerative disorders. In the present study we have investigated the effects of chronic (30 or 60 days) exposure to ozone on olfactory perception and memory and on levels of lipid peroxidation, alpha and beta estrogen receptors and dopamine beta-hydroxylase in the olfactory bulb in ovariectomized female rats. The ability of 17beta-estradiol to prevent these effects was then assessed. Results showed that ozone exposure for 30 or 60 days impaired formation/retention of a selective olfactory recognition memory 120 min after exposure to a juvenile stimulus animal with the effect at 60 days being significantly greater than at 30 days. They also showed impaired speed in locating a buried chocolate reward after 60 days of ozone exposure indicating some loss of olfactory perception. These functional impairments could all be prevented by coincident estradiol treatment. In the olfactory bulb, levels of lipid peroxidation were increased at both 30- and 60-day time-points and numbers of cells with immunohistochemical staining for alpha and beta estrogen receptors, and dopamine beta-hydroxylase were reduced as were alpha and beta estrogen receptor protein levels. These effects were prevented by estradiol treatment. Oxidative stress damage caused by chronic exposure to ozone does therefore impair olfactory perception and social recognition memory and may do so by reducing noradrenergic and estrogen receptor activity in the olfactory bulb. That these effects can be prevented by estradiol treatment suggests increased susceptibility to neurodegenerative disorders in aging women may be contributed to by reduced estrogen levels post-menopause.

Human Health and Economic Impacts of Ozone Reductions by Income Group.

PubMed

Saari, Rebecca K; Thompson, Tammy M; Selin, Noelle E

2017-02-21

Low-income households may be disproportionately affected by ozone pollution and ozone policy. We quantify how three factors affect the relative benefits of ozone policies with household income: (1) unequal ozone reductions; (2) policy delay; and (3) economic valuation methods. We model ozone concentrations under baseline and policy conditions across the full continental United States to estimate the distribution of ozone-related health impacts across nine income groups. We enhance an economic model to include these impacts across household income categories, and present its first application to evaluate the benefits of ozone reductions for low-income households. We find that mortality incidence rates decrease with increasing income. Modeled ozone levels yield a median of 11 deaths per 100 000 people in 2005. Proposed policy reduces these rates by 13%. Ozone reductions are highest among low-income households, which increases their relative welfare gains by up to 4% and decreases them for the rich by up to 8%. The median value of reductions in 2015 is either $30 billion (in 2006 U.S. dollars) or $1 billion if reduced mortality risks are valued with willingness-to-pay or as income from increased life expectancy. Ozone reductions were relatively twice as beneficial for the lowest- compared to the highest-income households. The valuation approach affected benefits more than a policy delay or differential ozone reductions with income.

Effects of ozone oxidative preconditioning on radiation-induced organ damage in rats

PubMed Central

Gultekin, Fatma Ayca; Bakkal, Bekir Hakan; Guven, Berrak; Tasdoven, Ilhan; Bektas, Sibel; Can, Murat; Comert, Mustafa

2013-01-01

Because radiation-induced cellular damage is attributed primarily to harmful effects of free radicals, molecules with direct free radical scavenging properties are particularly promising as radioprotectors. It has been demonstrated that controlled ozone administration may promote an adaptation to oxidative stress, preventing the damage induced by reactive oxygen species. Thus, we hypothesized that ozone would ameliorate oxidative damage caused by total body irradiation (TBI) with a single dose of 6 Gy in rat liver and ileum tissues. Rats were randomly divided into groups as follows: control group; saline-treated and irradiated (IR) groups; and ozone oxidative preconditioning (OOP) and IR groups. Animals were exposed to TBI after a 5-day intraperitoneal pretreatment with either saline or ozone (1 mg/kg/day). They were decapitated at either 6 h or 72 h after TBI. Plasma, liver and ileum samples were obtained. Serum AST, ALT and TNF-α levels were elevated in the IR groups compared with the control group and were decreased after treatment with OOP. TBI resulted in a significant increase in the levels of MDA in the liver and ileal tissues and a decrease of SOD activities. The results demonstrated that the levels of MDA liver and ileal tissues in irradiated rats that were pretreated with ozone were significantly decreased, while SOD activities were significantly increased. OOP reversed all histopathological alterations induced by irradiation. In conclusion, data obtained from this study indicated that ozone could increase the endogenous antioxidant defense mechanism in rats and there by protect the animals from radiation-induced organ toxicity. PMID:22915786

Fine-Scale Comparison of TOMS Total Ozone Data with Model Analysis of an Intense Midwestern Cyclone

NASA Technical Reports Server (NTRS)

Olsen, Mark A.; Gallus, William A., Jr.; Stanford, John L.; Brown, John M.

2000-01-01

High-resolution (approx. 40 km) along-track total column ozone data from the Total Ozone Mapping Spectrometer (TOMS) instrument are compared with a high-resolution mesoscale numerical model analysis of an intense cyclone in the Midwestern United States. Total ozone increased by 100 DU (nearly 38%) as the TOMS instrument passed over the associated tropopause fold region. Complex structure is seen in the meteorological fields and compares well with the total ozone observations. Ozone data support the meteorological analysis showing that stratospheric descent was confined to levels above approx. 600 hPa; significant positive potential vorticity at lower levels is attributable to diabetic processes. Likewise, meteorological fields show that two pronounced ozone streamers extending north and northeastward into Canada at high levels are not bands of stratospheric air feeding into the cyclone; one is a channel of exhaust downstream from the system, and the other apparently previously connected the main cyclonic circulation to a southward intrusion of polar stratospheric air and advected eastward as the cut-off cyclone evolved. Good agreement between small-scale features in the model output and total ozone data underscores the latter's potential usefulness in diagnosing upper tropospheric/lower stratospheric dynamics and kinematics.

Ozone-initiated chemistry in an occupied simulated aircraft cabin.

PubMed

Weschler, Charles J; Wisthaler, Armin; Cowlin, Shannon; Tamás, Gyöngyi; Strøm-Tejsen, Peter; Hodgson, Alfred T; Destaillats, Hugo; Herrington, Jason; Zhang, Junfeng; Nazaroff, William W

2007-09-01

We have used multiple analytical methods to characterize the gas-phase products formed when ozone was added to cabin air during simulated 4-hour flights that were conducted in a reconstructed section of a B-767 aircraft containing human occupants. Two separate groups of 16 females were each exposed to four conditions: low air exchange (4.4 (h-1)), <2 ppb ozone; low air exchange, 61-64 ppb ozone; high air exchange (8.8 h(-1)), <2 ppb ozone; and high air exchange, 73-77 ppb ozone. The addition of ozone to the cabin air increased the levels of identified byproducts from approximately 70 to 130 ppb at the lower air exchange rate and from approximately 30 to 70 ppb at the higher air exchange rate. Most of the increase was attributable to acetone, nonanal, decanal, 4-oxopentanal (4-OPA), 6-methyl-5-hepten-2-one (6-MHO), formic acid, and acetic acid, with 0.25-0.30 mol of quantified product volatilized per mol of ozone consumed. Several of these compounds reached levels above their reported odor thresholds. Most byproducts were derived from surface reactions with occupants and their clothing, consistent with the inference that occupants were responsible for the removal of >55% of the ozone in the cabin. The observations made in this study have implications for other indoor settings. Whenever human beings and ozone are simultaneously present, one anticipates production of acetone, nonanal, decanal, 6-MHO, geranyl acetone, and 4-OPA.

Therapeutic effect of ozone and rutin on adriamycin-induced testicular toxicity in an experimental rat model.

PubMed

Salem, E A; Salem, N A; Hellstrom, W J

2017-02-01

To evaluate the cytoprotective effects of rutin, ozone and their combination on adriamycin (ADR)-induced testicular toxicity, 50 male albino rats were classified into five groups of ten animals each as follows: placebo group; ADR group; ADR + rutin group; ADR + ozone group and ADR + rutin + ozone group. Sperm functions, testosterone (T), luteinising hormone (LH), follicle stimulating hormone (FSH), testicular enzymes, oxidant/antioxidant status, C-reactive protein, monocyte chemoattractant proteins-1 and leukotriene B4 were determined. After ADR injection, a decline in sperm functions was observed. FSH and LH levels were increased, T level and testicular enzymes were decreased, significant enhancement in oxidative stress with subsequent depletion in antioxidants was detected and inflammatory markers were significantly elevated. Treatment with rutin and/or ozone, however, improved the aforementioned parameters. Ozone therapy alone almost completely reversed the toxic effects of ADR and restored all parameters to normal levels. © 2016 Blackwell Verlag GmbH.

Trends of Rural Tropospheric Ozone at the Northwest of the Iberian Peninsula

PubMed Central

Saavedra, S.; Rodríguez, A.; Souto, J. A.; Casares, J. J.; Bermúdez, J. L.; Soto, B.

2012-01-01

Tropospheric ozone levels around urban and suburban areas at Europe and North America had increased during 80's–90's, until the application of NOx reduction strategies. However, as it was expected, this ozone depletion was not proportional to the emissions reduction. On the other hand, rural ozone levels show different trends, with peaks reduction and average increments; this different evolution could be explained by either emission changes or climate variability in a region. In this work, trends of tropospheric ozone episodes at rural sites in the northwest of the Iberian Peninsula were analyzed and compared to others observed in different regions of the Atlantic European coast. Special interest was focused on the air quality sites characterization, in order to guarantee their rural character in terms of air quality. Both episodic local meteorological and air quality measurements along five years were considered, in order to study possible meteorological influences in ozone levels, different to other European Atlantic regions. PMID:22649298

Trends of rural tropospheric ozone at the northwest of the Iberian Peninsula.

PubMed

Saavedra, S; Rodríguez, A; Souto, J A; Casares, J J; Bermúdez, J L; Soto, B

2012-01-01

Tropospheric ozone levels around urban and suburban areas at Europe and North America had increased during 80's-90's, until the application of NO(x) reduction strategies. However, as it was expected, this ozone depletion was not proportional to the emissions reduction. On the other hand, rural ozone levels show different trends, with peaks reduction and average increments; this different evolution could be explained by either emission changes or climate variability in a region. In this work, trends of tropospheric ozone episodes at rural sites in the northwest of the Iberian Peninsula were analyzed and compared to others observed in different regions of the Atlantic European coast. Special interest was focused on the air quality sites characterization, in order to guarantee their rural character in terms of air quality. Both episodic local meteorological and air quality measurements along five years were considered, in order to study possible meteorological influences in ozone levels, different to other European Atlantic regions.

Ultraviolet-ozone treatment reduces levels of disease-associated prion protein and prion infectivity

USGS Publications Warehouse

Johnson, C.J.; Gilbert, P.; McKenzie, D.; Pedersen, J.A.; Aiken, Judd M.

2009-01-01

Background. Transmissible spongiform encephalopathies (TSEs) are a group of fatal neurodegenerative diseases caused by novel infectious agents referred to as prions. Prions appear to be composed primarily, if not exclusively, of a misfolded isoform of the cellular prion protein. TSE infectivity is remarkably stable and can resist many aggressive decontamination procedures, increasing human, livestock and wildlife exposure to TSEs. Findings. We tested the hypothesis that UV-ozone treatment reduces levels of the pathogenic prion protein and inactivates the infectious agent. We found that UV-ozone treatment decreased the carbon and prion protein content in infected brain homogenate to levels undetectable by dry-ashing carbon analysis or immunoblotting, respectively. After 8 weeks of ashing, UV-ozone treatment reduced the infectious titer of treated material by a factor of at least 105. A small amount of infectivity, however, persisted despite UV-ozone treatment. When bound to either montmorillonite clay or quartz surfaces, PrPTSE was still susceptible to degradation by UV-ozone. Conclusion. Our findings strongly suggest that UV-ozone treatment can degrade pathogenic prion protein and inactivate prions, even when the agent is associated with surfaces. Using larger UV-ozone doses or combining UV-ozone treatment with other decontaminant methods may allow the sterilization of TSE-contaminated materials. ?? 2009 Aiken et al; licensee BioMed Central Ltd.

Ozone, Fine Particulate Matter, and Chronic Lower Respiratory Disease Mortality in the United States.

PubMed

Hao, Yongping; Balluz, Lina; Strosnider, Heather; Wen, Xiao Jun; Li, Chaoyang; Qualters, Judith R

2015-08-01

Short-term effects of air pollution exposure on respiratory disease mortality are well established. However, few studies have examined the effects of long-term exposure, and among those that have, results are inconsistent. To evaluate long-term association between ambient ozone, fine particulate matter (PM2.5, particles with an aerodynamic diameter of 2.5 μm or less), and chronic lower respiratory disease (CLRD) mortality in the contiguous United States. We fit Bayesian hierarchical spatial Poisson models, adjusting for five county-level covariates (percentage of adults aged ≥65 years, poverty, lifetime smoking, obesity, and temperature), with random effects at state and county levels to account for spatial heterogeneity and spatial dependence. We derived county-level average daily concentration levels for ambient ozone and PM2.5 for 2001-2008 from the U.S. Environmental Protection Agency's down-scaled estimates and obtained 2007-2008 CLRD deaths from the National Center for Health Statistics. Exposure to ambient ozone was associated with an increased rate of CLRD deaths, with a rate ratio of 1.05 (95% credible interval, 1.01-1.09) per 5-ppb increase in ozone; the association between ambient PM2.5 and CLRD mortality was positive but statistically insignificant (rate ratio, 1.07; 95% credible interval, 0.99-1.14). This study links air pollution exposure data with CLRD mortality for all 3,109 contiguous U.S. counties. Ambient ozone may be associated with an increased rate of death from CLRD in the contiguous United States. Although we adjusted for selected county-level covariates and unobserved influences through Bayesian hierarchical spatial modeling, the possibility of ecologic bias remains.

Modeling vascular inflammation and atherogenicity after inhalation of ambient levels of ozone: exploratory lessons from transcriptomics.

PubMed

Tham, Andrea; Lullo, Dominic; Dalton, Sarah; Zeng, Siyang; van Koeverden, Ian; Arjomandi, Mehrdad

2017-02-01

Epidemiologic studies have linked inhalation of air pollutants such as ozone to cardiovascular mortality. Human exposure studies have shown that inhalation of ambient levels of ozone causes airway and systemic inflammation and an imbalance in sympathetic/parasympathetic tone. To explore molecular mechanisms through which ozone inhalation contributes to cardiovascular mortality, we compared transcriptomics data previously obtained from bronchoalveolar lavage (BAL) cells obtained from healthy subjects after inhalational exposure to ozone (200 ppb for 4 h) to those of various cell samples from 11 published studies of patients with atherosclerotic disease using the Nextbio genomic data platform. Overlapping gene ontologies that may be involved in the transition from pulmonary to systemic vascular inflammation after ozone inhalation were explored. Local and systemic enzymatic activity of an overlapping upregulated gene, matrix metalloproteinase-9 (MMP-9), was measured by zymography after ozone exposure. A set of differentially expressed genes involved in response to stimulus, stress, and wounding were in common between the ozone and most of the atherosclerosis studies. Many of these genes contribute to biological processes such as cholesterol metabolism dysfunction, increased monocyte adherence, endothelial cell lesions, and matrix remodeling, and to diseases such as heart failure, ischemia, and atherosclerotic occlusive disease. Inhalation of ozone increased MMP-9 enzymatic activity in both BAL fluid and serum. Comparison of transcriptomics between BAL cells after ozone exposure and various cell types from patients with atherosclerotic disease reveals commonly regulated processes and potential mechanisms by which ozone inhalation may contribute to progression of pre-existent atherosclerotic lesions.

Elevated tropospheric ozone increased grain protein and amino acid content of a hybrid rice without manipulation by planting density.

PubMed

Zhou, Xiaodong; Zhou, Juan; Wang, Yunxia; Peng, Bin; Zhu, Jianguo; Yang, Lianxin; Wang, Yulong

2015-01-01

Rising tropospheric ozone affects crop yield and quality. Rice protein concentration, which is closely associated with eating/cooking quality, is of critical importance to nutritional quality. The ozone effect on amino acids of rice grains was little known, especially grown under different cultivation conditions. A hybrid rice cultivar Shanyou 63 was grown in 2010 and 2011 to investigate the interactive effect of ozone exposure and planting density on rice protein quality in a free-air ozone enrichment system. The content of protein, total amino acids (TAA), total essential (TEAA) and non-essential amino acids (TNEAA) in rice grain was increased by 12-14% with elevated ozone. A similar significant response to ozone was observed for concentrations of the seven essential and eight non-essential amino acids. In contrast, elevated ozone caused a small but significant decrease in percentage of TEAA to TAA. The year effect was significant for all measured traits; however, interactions of ozone with year or planting density were not detected. The study suggested that season-long elevation of ozone concentration to projected 2050 levels will increase protein and amino acids of Shanyou 63, and crop management such as changing planting density might not alter the impact. © 2014 Society of Chemical Industry.

Interaction of ozone exposure with airway hyperresponsiveness and inflammation induced by trimellitic anhydride in sensitized guinea pigs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Jian; Chung, K.Fan

1997-09-01

The effect of prior ozone (O{sub 3}) exposure on airway hyperresponsiveness and inflammation induced by trimellitic anhydride (TMA) has been investigated in TMA-sensitized guinea pigs. Airway responsiveness was measured as the concentration of acetylcholine needed to increase baseline lung resistance (RL) by 300% (PC300). Ozone (3 ppm, for 3 h) caused an increase in-log PC300 at 1 h after exposure, with return of -log PC300 to control levels at 8 h. Ozone also increased baseline RL at 8 h. TMA challenge increase -log PC300 in TMA-sensitized guinea pigs at 8 h after challenge from 3.85 {+-} 0.09 to 4.11 {+-}more » 0.09. Ozone exposure prior to TMA challenge prevented the induction of airway hyperresponsiveness with a mean -log PC300 of 3.51 {+-} 0.20, which was not different from that of control TMA-Sensitized group. Baseline RL was significantly higher in ozone-pretreated animals after TMA challenge when compared to those of either control or challenged with TMA alone. Ozone had no effect on TMA challenge-induced BAL eosinophilia and neutrophilia. We conclude that a single exposure to ozone inhibits the increase in airway responsiveness, but increases the bronchoconstrictor response induced by TMA in TMA-Sensitized guinea pigs; however, the inflammatory airway response to TMA is unchanged by preexposure to ozone. 29 refs., 2 figs., 1 tab.« less

Progress in understanding the formation of fine particulate matter and ground-level ozone in Pearl River Delta region, China

NASA Astrophysics Data System (ADS)

Wang, Xuemei; Wang, Tao; Zheng, Junyu; Shao, Min; Wang, Xinming

2015-12-01

In the past three decades, the Pearl River Delta of China has been suffered from severe air pollution due to the rapid increase in energy consumption associated with industrialization and urbanization of the region. The number of hazy days, increased from below 20 days in a year before 1970, to more than 150 days a year during 1980 and 2000. The ground-level ozone levels have also on the rise, with hourly concentration of 160 ppbv being observed in Guangzhou and 201 ppbv in nearby Hong Kong (Zhang et al., 2008). The ozone pollution has been difficult to reduce even in air quality improvement program for the Guangzhou Asian Games (Liu et al., 2013).

Acute Ozone-Induced Pulmonary and Systemic Metabolic Effects Are Diminished in Adrenalectomized Rats

PubMed Central

Miller, Desinia B.; Snow, Samantha J.; Schladweiler, Mette C.; Richards, Judy E.; Ghio, Andrew J.; Ledbetter, Allen D.; Kodavanti, Urmila P.

2016-01-01

Acute ozone exposure increases circulating stress hormones and induces metabolic alterations in animals. We hypothesized that the increase of adrenal-derived stress hormones is necessary for both ozone-induced metabolic effects and lung injury. Male Wistar-Kyoto rats underwent bilateral adrenal demedullation (DEMED), total bilateral adrenalectomy (ADREX), or sham surgery (SHAM). After a 4 day recovery, rats were exposed to air or ozone (1 ppm), 4 h/day for 1 or 2 days and responses assessed immediately postexposure. Circulating adrenaline levels dropped to nearly zero in DEMED and ADREX rats relative to SHAM. Corticosterone tended to be low in DEMED rats and dropped to nearly zero in ADREX rats. Adrenalectomy in air-exposed rats caused modest changes in metabolites and lung toxicity parameters. Ozone-induced hyperglycemia and glucose intolerance were markedly attenuated in DEMED rats with nearly complete reversal in ADREX rats. Ozone increased circulating epinephrine and corticosterone in SHAM but not in DEMED or ADREX rats. Free fatty acids (P = .15) and branched-chain amino acids increased after ozone exposure in SHAM but not in DEMED or ADREX rats. Lung minute volume was not affected by surgery or ozone but ozone-induced labored breathing was less pronounced in ADREX rats. Ozone-induced increases in lung protein leakage and neutrophilic inflammation were markedly reduced in DEMED and ADREX rats (ADREX > DEMED). Ozone-mediated decreases in circulating white blood cells in SHAM were not observed in DEMED and ADREX rats. We demonstrate that ozone-induced peripheral metabolic effects and lung injury/inflammation are mediated through adrenal-derived stress hormones likely via the activation of stress response pathway. PMID:26732886

Tropospheric ozone reduces carbon assimilation in trees: estimates from analysis of continuous flux measurements.

PubMed

Fares, Silvano; Vargas, Rodrigo; Detto, Matteo; Goldstein, Allen H; Karlik, John; Paoletti, Elena; Vitale, Marcello

2013-08-01

High ground-level ozone concentrations are typical of Mediterranean climates. Plant exposure to this oxidant is known to reduce carbon assimilation. Ozone damage has been traditionally measured through manipulative experiments that do not consider long-term exposure and propagate large uncertainty by up-scaling leaf-level observations to ecosystem-level interpretations. We analyzed long-term continuous measurements (>9 site-years at 30 min resolution) of environmental and eco-physiological parameters at three Mediterranean ecosystems: (i) forest site dominated by Pinus ponderosa in the Sierra Mountains in California, USA; (ii) forest site composed of a mixture of Quercus spp. and P. pinea in the Tyrrhenian sea coast near Rome, Italy; and (iii) orchard site of Citrus sinensis cultivated in the California Central Valley, USA. We hypothesized that higher levels of ozone concentration in the atmosphere result in a decrease in carbon assimilation by trees under field conditions. This hypothesis was tested using time series analysis such as wavelet coherence and spectral Granger causality, and complemented with multivariate linear and nonlinear statistical analyses. We found that reduction in carbon assimilation was more related to stomatal ozone deposition than to ozone concentration. The negative effects of ozone occurred within a day of exposure/uptake. Decoupling between carbon assimilation and stomatal aperture increased with the amount of ozone pollution. Up to 12-19% of the carbon assimilation reduction in P. ponderosa and in the Citrus plantation was explained by higher stomatal ozone deposition. In contrast, the Italian site did not show reductions in gross primary productivity either by ozone concentration or stomatal ozone deposition, mainly due to the lower ozone concentrations in the periurban site over the shorter period of investigation. These results highlight the importance of plant adaptation/sensitivity under field conditions, and the importance of continuous long-term measurements to explain ozone damage to real-world forests and calculate metrics for ozone-risk assessment. © 2013 John Wiley & Sons Ltd.

Total ozone influence on the surface UV-B radiation in the late spring-summer 1963-1997: An analysis of multiple timescales

NASA Astrophysics Data System (ADS)

KrzyśCin, Janusz W.

2000-02-01

Monthly means and minima of total ozone for the late springs and summers (May-August) of 1963-1997 have been examined for the European Dobson stations (Arosa, Belsk, Hohenpeissenberg, Hradec Kralove, Uccle). It is shown that long-term tendencies in total ozone means were almost similar to those in the total ozone minima. Analyses of the late spring/summer means of UV daily doses, total ozone, and global solar radiation (proxy for the overall atmospheric transparency), measured at Belsk (52°N, 21°E) for the period 1976-1996, show that an importance of the total ozone changes for the UV-B level increases with the timescale. Decadal variations in total ozone are the main source of the UV trend at Belsk. Frequency of appearance of extreme daily total ozone values in the selected late spring/summer season seems to be important for analyses of the ozone forcing in the interannual timescale. Regional and temporal differences in the number of days with extreme low ozone values are discussed using the total ozone extrema taken at Arosa, Belsk, and Hradec Kralove in the 1963-1997 period. A statistical model is developed for diagnosis of the next day value of the UV-B level. The changes in the overall atmospheric transparency are essential for the UV-B level when the day-to-day variations in the UV forcing factors are examined.

Climate-driven ground-level ozone extreme in the fall over the Southeast United States

PubMed Central

Wang, Yuhang

2016-01-01

Ground-level ozone is adverse to human and vegetation health. High ground-level ozone concentrations usually occur over the United States in the summer, often referred to as the ozone season. However, observed monthly mean ozone concentrations in the southeastern United States were higher in October than July in 2010. The October ozone average in 2010 reached that of July in the past three decades (1980–2010). Our analysis shows that this extreme October ozone in 2010 over the Southeast is due in part to a dry and warm weather condition, which enhances photochemical production, air stagnation, and fire emissions. Observational evidence and modeling analysis also indicate that another significant contributor is enhanced emissions of biogenic isoprene, a major ozone precursor, from water-stressed plants under a dry and warm condition. The latter finding is corroborated by recent laboratory and field studies. This climate-induced biogenic control also explains the puzzling fact that the two extremes of high October ozone both occurred in the 2000s when anthropogenic emissions were lower than the 1980s and 1990s, in contrast to the observed decreasing trend of July ozone in the region. The occurrences of a drying and warming fall, projected by climate models, will likely lead to more active photochemistry, enhanced biogenic isoprene and fire emissions, an extension of the ozone season from summer to fall, and an increase of secondary organic aerosols in the Southeast, posing challenges to regional air quality management. PMID:27551089

Tropospheric ozone using an emission tagging technique in the CAM-Chem and WRF-Chem models

NASA Astrophysics Data System (ADS)

Lupascu, A.; Coates, J.; Zhu, S.; Butler, T. M.

2017-12-01

Tropospheric ozone is a short-lived climate forcing pollutant. High concentration of ozone can affect human health (cardiorespiratory and increased mortality due to long-term exposure), and also it damages crops. Attributing ozone concentrations to the contributions from different sources would indicate the effects of locally emitted or transported precursors on ozone levels in specific regions. This information could be used as an important component of the design of emissions reduction strategies by indicating which emission sources could be targeted for effective reductions, thus reducing the burden of ozone pollution. Using a "tagging" approach within the CAM-Chem (global) and WRF-Chem (regional) models, we can quantify the contribution of individual emission of NOx and VOC precursors on air quality. Hence, when precursor emissions of NOx are tagged, we have seen that the largest contributors on ozone levels are the anthropogenic sources, while in the case of precursor emissions of VOCs, the biogenic sources and methane account for more than 50% of ozone levels. Further, we have extended the NOx tagging method in order to investigate continental source region contributions to concentrations of ozone over various receptor regions over the globe, with a zoom over Europe. In general, summertime maximum ozone in most receptor regions is largely attributable to local emissions of anthropogenic NOx and biogenic VOC. During the rest of the year, especially during springtime, ozone in most receptor regions shows stronger influences from anthropogenic emissions of NOx and VOC in remote source regions.

Analysis of European ozone trends in the period 1995-2014

NASA Astrophysics Data System (ADS)

Yan, Yingying; Pozzer, Andrea; Ojha, Narendra; Lin, Jintai; Lelieveld, Jos

2018-04-01

Surface-based measurements from the EMEP and Airbase networks are used to estimate the changes in surface ozone levels during the 1995-2014 period over Europe. We find significant ozone enhancements (0.20-0.59 µg m-3 yr-1 for the annual means; P-value < 0.01 according to an F-test) over the European suburban and urban stations during 1995-2012 based on the Airbase sites. For European background ozone observed at EMEP sites, it is shown that a significantly decreasing trend in the 95th percentile ozone concentrations has occurred, especially at noon (0.9 µg m-3 yr-1; P-value < 0.01), while the 5th percentile ozone concentrations continued to increase with a trend of 0.3 µg m-3 yr-1 (P-value < 0.01) during the study period. With the help of numerical simulations performed with the global chemistry-climate model EMAC, the importance of anthropogenic emissions changes in determining these changes over background sites are investigated. The EMAC model is found to successfully capture the observed temporal variability in mean ozone concentrations, as well as the contrast in the trends of 95th and 5th percentile ozone over Europe. Sensitivity simulations and statistical analysis show that a decrease in European anthropogenic emissions had contrasting effects on surface ozone trends between the 95th and 5th percentile levels and that background ozone levels have been influenced by hemispheric transport, while climate variability generally regulated the inter-annual variations of surface ozone in Europe.

Climate-driven ground-level ozone extreme in the fall over the Southeast United States.

PubMed

Zhang, Yuzhong; Wang, Yuhang

2016-09-06

Ground-level ozone is adverse to human and vegetation health. High ground-level ozone concentrations usually occur over the United States in the summer, often referred to as the ozone season. However, observed monthly mean ozone concentrations in the southeastern United States were higher in October than July in 2010. The October ozone average in 2010 reached that of July in the past three decades (1980-2010). Our analysis shows that this extreme October ozone in 2010 over the Southeast is due in part to a dry and warm weather condition, which enhances photochemical production, air stagnation, and fire emissions. Observational evidence and modeling analysis also indicate that another significant contributor is enhanced emissions of biogenic isoprene, a major ozone precursor, from water-stressed plants under a dry and warm condition. The latter finding is corroborated by recent laboratory and field studies. This climate-induced biogenic control also explains the puzzling fact that the two extremes of high October ozone both occurred in the 2000s when anthropogenic emissions were lower than the 1980s and 1990s, in contrast to the observed decreasing trend of July ozone in the region. The occurrences of a drying and warming fall, projected by climate models, will likely lead to more active photochemistry, enhanced biogenic isoprene and fire emissions, an extension of the ozone season from summer to fall, and an increase of secondary organic aerosols in the Southeast, posing challenges to regional air quality management.

An RNA-Seq study reveals genetic responses of diverse wild soybean accessions to increased ozone levels

USDA-ARS?s Scientific Manuscript database

Ozone is a pollutant widely known to cause decrease in productivity in many plant species, including soybean. While cultivated soybean response to ozone has been studied, less work has been done to identify sources of resistance from wild relatives. This study presents a putative SNP marker on Chrom...

Potential impacts of ambient ozone on wheat rust diseases and the role of plant ozone sensitivity

USDA-ARS?s Scientific Manuscript database

The resurgence of rust diseases and the continued rise in tropospheric ozone (O3) levels have the potential to limit global wheat production. We conducted a series of experiments to understand the potential interactions between these two stress factors. Both stem rust and leaf rust were increased o...

Lung Function and Inflammatory responses in healthy young adults exposed to 0.06 ppm Ozone for 6.6 hours

EPA Science Inventory

Rationale: Exposure to ozone causes a decrease in spirometric lung function and an increase in airway inflammation in healthy young adults at concentrations as low as 0.08 ppm close to the the National Ambient Air Quality Standard for ground level ozone. Objectives: To test wheth...

Understanding Differences in Chemistry Climate Model Projections of Stratospheric Ozone

NASA Technical Reports Server (NTRS)

Douglass, A. R.; Strahan, S. E.; Oman, L. D.; Stolarski, R. S.

2014-01-01

Chemistry climate models (CCMs) are used to project future evolution of stratospheric ozone as concentrations of ozone-depleting substances (ODSs) decrease and greenhouse gases increase, cooling the stratosphere. CCM projections exhibit not only many common features but also a broad range of values for quantities such as year of ozone return to 1980 and global ozone level at the end of the 21st century. Multiple linear regression is applied to each of 14 CCMs to separate ozone response to ODS concentration change from that due to climate change. We show that the sensitivity of lower stratospheric ozone to chlorine change Delta Ozone/Delta inorganic chlorine is a near-linear function of partitioning of total inorganic chlorine into its reservoirs; both inorganic chlorine and its partitioning are largely controlled by lower stratospheric transport. CCMs with best performance on transport diagnostics agree with observations for chlorine reservoirs and produce similar ozone responses to chlorine change. After 2035, differences in Delta Ozone/Delta inorganic chlorine contribute little to the spread in CCM projections as the anthropogenic contribution to inorganic chlorine becomes unimportant. Differences among upper stratospheric ozone increases due to temperature decreases are explained by differences in ozone sensitivity to temperature change Delta Ozone/Delta T due to different contributions from various ozone loss processes, each with its own temperature dependence. Ozone decrease in the tropical lower stratosphere caused by a projected speedup in the Brewer-Dobson circulation may or may not be balanced by ozone increases in the middle- and high-latitude lower stratosphere and upper troposphere. This balance, or lack thereof, contributes most to the spread in late 21st century projections.

Effect of pulsed corona discharge voltage and feed gas flow rate on dissolved ozone concentration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prasetyaningrum, A., E-mail: ajiprasetyaningrum@gmail.com; Ratnawati,; Jos, B.

Ozonization is one of the methods extensively used for water purification and degradation of organic materials. Ozone (O{sub 3}) is recognized as a powerful oxidizing agent. Due to its strong oxidability and better environmental friendless, ozone increasing being used in domestic and industrial applications. Current technology in ozone production utilizes several techniques (corona discharge, ultra violet radiation and electrolysis). This experiment aimed to evaluating effect of voltage and gas flow rate on ozone production with corona discharge. The system consists of two net-type stainless steel electrode placed in a dielectric barrier. Three pulsed voltage (20, 30, 40 KV) and flowmore » rate (5, 10, 15 L/min) were prepare for operation variable at high frequency (3.7 kHz) with AC pulsed power supply. The dissolved ozone concentration depends on the applied high-voltage level, gas flow rate and the discharge exposure duration. The ozone concentration increases with decreasing gas flow rate. Dissolved ozone concentrations greater than 200 ppm can be obtained with a minimum voltage 40 kV.« less

Effect of pulsed corona discharge voltage and feed gas flow rate on dissolved ozone concentration

NASA Astrophysics Data System (ADS)

Prasetyaningrum, A.; Ratnawati, Jos, B.

2015-12-01

Ozonization is one of the methods extensively used for water purification and degradation of organic materials. Ozone (O3) is recognized as a powerful oxidizing agent. Due to its strong oxidability and better environmental friendless, ozone increasing being used in domestic and industrial applications. Current technology in ozone production utilizes several techniques (corona discharge, ultra violet radiation and electrolysis). This experiment aimed to evaluating effect of voltage and gas flow rate on ozone production with corona discharge. The system consists of two net-type stainless steel electrode placed in a dielectric barrier. Three pulsed voltage (20, 30, 40 KV) and flow rate (5, 10, 15 L/min) were prepare for operation variable at high frequency (3.7 kHz) with AC pulsed power supply. The dissolved ozone concentration depends on the applied high-voltage level, gas flow rate and the discharge exposure duration. The ozone concentration increases with decreasing gas flow rate. Dissolved ozone concentrations greater than 200 ppm can be obtained with a minimum voltage 40 kV.

The challenge of making ozone risk assessment for forest trees more mechanistic

USDA-ARS?s Scientific Manuscript database

In the upcoming decades, the earth’s atmosphere will contain increasing levels of carbon dioxide and possibly tropospheric ozone. The latter constitute a risk for vegetation, including forest ecosystems, counteracting the ability to sequester carbon. In view of climate change, the need increases f...

Impacts of stratospheric sulfate geoengineering on tropospheric ozone

NASA Astrophysics Data System (ADS)

Xia, Lili; Nowack, Peer J.; Tilmes, Simone; Robock, Alan

2017-10-01

A range of solar radiation management (SRM) techniques has been proposed to counter anthropogenic climate change. Here, we examine the potential effects of stratospheric sulfate aerosols and solar insolation reduction on tropospheric ozone and ozone at Earth's surface. Ozone is a key air pollutant, which can produce respiratory diseases and crop damage. Using a version of the Community Earth System Model from the National Center for Atmospheric Research that includes comprehensive tropospheric and stratospheric chemistry, we model both stratospheric sulfur injection and solar irradiance reduction schemes, with the aim of achieving equal levels of surface cooling relative to the Representative Concentration Pathway 6.0 scenario. This allows us to compare the impacts of sulfate aerosols and solar dimming on atmospheric ozone concentrations. Despite nearly identical global mean surface temperatures for the two SRM approaches, solar insolation reduction increases global average surface ozone concentrations, while sulfate injection decreases it. A fundamental difference between the two geoengineering schemes is the importance of heterogeneous reactions in the photochemical ozone balance with larger stratospheric sulfate abundance, resulting in increased ozone depletion in mid- and high latitudes. This reduces the net transport of stratospheric ozone into the troposphere and thus is a key driver of the overall decrease in surface ozone. At the same time, the change in stratospheric ozone alters the tropospheric photochemical environment due to enhanced ultraviolet radiation. A shared factor among both SRM scenarios is decreased chemical ozone loss due to reduced tropospheric humidity. Under insolation reduction, this is the dominant factor giving rise to the global surface ozone increase. Regionally, both surface ozone increases and decreases are found for both scenarios; that is, SRM would affect regions of the world differently in terms of air pollution. In conclusion, surface ozone and tropospheric chemistry would likely be affected by SRM, but the overall effect is strongly dependent on the SRM scheme. Due to the health and economic impacts of surface ozone, all these impacts should be taken into account in evaluations of possible consequences of SRM.

Reducing Uncertainty in Chemistry Climate Model Predictions of Stratospheric Ozone

NASA Technical Reports Server (NTRS)

Douglass, A. R.; Strahan, S. E.; Oman, L. D.; Stolarski, R. S.

2014-01-01

Chemistry climate models (CCMs) are used to predict the future evolution of stratospheric ozone as ozone-depleting substances decrease and greenhouse gases increase, cooling the stratosphere. CCM predictions exhibit many common features, but also a broad range of values for quantities such as year of ozone-return-to-1980 and global ozone level at the end of the 21st century. Multiple linear regression is applied to each of 14 CCMs to separate ozone response to chlorine change from that due to climate change. We show that the sensitivity of lower atmosphere ozone to chlorine change deltaO3/deltaCly is a near linear function of partitioning of total inorganic chlorine (Cly) into its reservoirs; both Cly and its partitioning are controlled by lower atmospheric transport. CCMs with realistic transport agree with observations for chlorine reservoirs and produce similar ozone responses to chlorine change. After 2035 differences in response to chlorine contribute little to the spread in CCM results as the anthropogenic contribution to Cly becomes unimportant. Differences among upper stratospheric ozone increases due to temperature decreases are explained by differences in ozone sensitivity to temperature change deltaO3/deltaT due to different contributions from various ozone loss processes, each with their own temperature dependence. In the lower atmosphere, tropical ozone decreases caused by a predicted speed-up in the Brewer-Dobson circulation may or may not be balanced by middle and high latitude increases, contributing most to the spread in late 21st century predictions.

Stage-specific, Nonlinear Surface Ozone Damage to Rice Production in China

NASA Astrophysics Data System (ADS)

Carter, Colin A.; Cui, Xiaomeng; Ding, Aijun; Ghanem, Dalia; Jiang, Fei; Yi, Fujin; Zhong, Funing

2017-03-01

China is one of the most heavily polluted nations and is also the largest agricultural producer. There are relatively few studies measuring the effects of pollution on crop yields in China, and most are based on experiments or simulation methods. We use observational data to study the impact of increased air pollution (surface ozone) on rice yields in Southeast China. We examine nonlinearities in the relationship between rice yields and ozone concentrations and find that an additional day with a maximum ozone concentration greater than 120 ppb is associated with a yield loss of 1.12% ± 0.83% relative to a day with maximum ozone concentration less than 60 ppb. We find that increases in mean ozone concentrations, SUM60, and AOT40 during panicle formation are associated with statistically significant yield losses, whereas such increases before and after panicle formation are not. We conclude that heightened surface ozone levels will potentially lead to reductions in rice yields that are large enough to have implications for the global rice market.

Ozonation performance of WWTP secondary effluent of antibiotic manufacturing wastewater.

PubMed

Zheng, Shaokui; Cui, Cancan; Liang, Qianjin; Xia, Xinghui; Yang, Fan

2010-11-01

The ozonation performance of wastewater treatment plant secondary effluent of oxytetracycline (OTC) manufacturing wastewater was investigated in terms of ozone dosage and initial pH levels when OTC contributed to a negligible fraction in the chemical oxygen demand (COD) ingredients of the medium-organic-strength wastewater with low biodegradability. A particular emphasis was placed on ammonia, OTC, and residual antibacterial activity (RAA) (evaluated using the objective pathogenic bacterium Staphylococcus aureus). It appears that an ozone dosage of 657 mg L⁻¹ (120 min of reaction) was enough to achieve an OTC abatement of 96%, and COD and biochemical oxygen demand removals of 29% and 33%, respectively, at initial levels of 10.4, 1360, and 300 mg L⁻¹ , respectively. There is a clear correlation between complete OTC depletion and complete RAA disappearance with an increase of ozone dosage. The presence of plentiful non-antibiotic refractory substances influenced the determination of the optimum ozone dosage for biodegradability enhancement and OTC/RAA reduction as well as the ozonation transformation of NH(3). The initial pH adjustment from the original level (pH 9) to pH 11 significantly reduced COD removal while RAA and NH(3) levels were not significantly influenced. Copyright © 2010 Elsevier Ltd. All rights reserved.

Analysis of impacts of urban land use and land cover on air quality in the Las Vegas region using remote sensing information and ground observations

USGS Publications Warehouse

Xian, G.

2007-01-01

Urban development in the Las Vegas Valley of Nevada (USA) has expanded rapidly over the past 50 years. The air quality in the valley has suffered owing to increases from anthropogenic emissions of carbon monoxide, ozone and criteria pollutants of particular matter. Air quality observations show that pollutant concentrations have apparent heterogeneous characteristics in the urban area. Quantified urban land use and land cover information derived from satellite remote sensing data indicate an apparent local influence of urban development density on air pollutant distributions. Multi‐year observational data collected by a network of local air monitoring stations specify that ozone maximums develop in the May and June timeframe, whereas minimum concentrations generally occur from November to February. The fine particulate matter maximum occurs in July. Ozone concentrations are highest on the west and northwest sides of the valley. Night‐time ozone reduction contributes to the heterogeneous features of the spatial distribution for average ozone levels in the Las Vegas metropolitan area. Decreased ozone levels associated with increased urban development density suggest that the highest ozone and lowest nitrogen oxides concentrations are associated with medium to low density urban development in Las Vegas.

Ozone Enhances Pulmonary Innate Immune Response to a Toll-Like Receptor–2 Agonist

PubMed Central

Oakes, Judy L.; O’Connor, Brian P.; Warg, Laura A.; Burton, Rachel; Hock, Ashley; Loader, Joan; LaFlamme, Daniel; Jing, Jian; Hui, Lucy; Schwartz, David A.

2013-01-01

Previous work demonstrated that pre-exposure to ozone primes innate immunity and increases Toll-like receptor–4 (TLR4)–mediated responses to subsequent stimulation with LPS. To explore the pulmonary innate immune response to ozone exposure further, we investigated the effects of ozone in combination with Pam3CYS, a synthetic TLR2/TLR1 agonist. Whole-lung lavage (WLL) and lung tissue were harvested from C57BL/6 mice after exposure to ozone or filtered air, followed by saline or Pam3CYS 24 hours later. Cells and cytokines in the WLL, the surface expression of TLRs on macrophages, and lung RNA genomic expression profiles were examined. We demonstrated an increased WLL cell influx, increased IL-6 and chemokine KC (Cxcl1), and decreased macrophage inflammatory protein (MIP)-1α and TNF-α in response to Pam3CYS as a result of ozone pre-exposure. We also observed the increased cell surface expression of TLR4, TLR2, and TLR1 on macrophages as a result of ozone alone or in combination with Pam3CYS. Gene expression analysis of lung tissue revealed a significant increase in the expression of genes related to injury repair and the cell cycle as a result of ozone alone or in combination with Pam3CYS. Our results extend previous findings with ozone/LPS to other TLR ligands, and suggest that the ozone priming of innate immunity is a general mechanism. Gene expression profiling of lung tissue identified transcriptional networks and genes that contribute to the priming of innate immunity at the molecular level. PMID:23002100

Ozone response to enhanced heterogeneous processing after the eruption of Mt. Pinatubo

NASA Technical Reports Server (NTRS)

Rodriguez, Jose M.; Ko, M. K. W.; Sze, N. D.; Heisey, C. W.; Yue, G. K.; Mccormick, M. P.

1994-01-01

Increases in aerosol loading after the Pinatubo eruption are expected to cause additional ozone depletion. Even though aerosol loadings were highest in the winter of 1991-1992, recent analyses of satellite and ground-based ozone measurements indicate that ozone levels in the winter of 1992-1993 are the lowest recorded in recent years, raising the question of the mechanisms responsible for such behavior. We have incorporated aerosol surface areas derived from the Stratospheric Aerosol and Gas Experiment II (SAGE-II) measurements into our two-dimensional model. Inclusion of heterogeneous chemsitry on these enhanced aerosol surfaces yields maximum ozone reductions during the winter of 1992-1993 in the Northern Hemisphere, consistent with those derived from observations. This delayed behavior is due to the combination of the non-linear nature of the impact of heterogeneous reactions as a function of aerosol surface area, and the long time constants for ozone in the lower stratosphere. If heterogeneous mechanisms are primarily responsible for the low 1992-1993 ozone levels, we expect ozone concentrations to start recovering in 1994.

Influence of future cropland expansion on regional and global tropospheric ozone

NASA Astrophysics Data System (ADS)

Squire, Oliver; Archibald, Alex; Telford, Paul; Pyle, John

2013-04-01

With the global population set to rise over the next 100 years, the fraction of land used for crop cultivation is likely to increase, the trend being most pronounced in developing regions such as Brazil and South East Asia. In these regions currently there stands natural rainforest, a high emitter of isoprene. As many staple crops, such as soy bean, are low emitters of isoprene, increasing the crop fraction in these regions will decrease isoprene emissions. Ozone over ~35 ppb has been shown to be damaging to plants, and as ground level ozone is sensitive to isoprene concentrations, altering isoprene emissions could increase ground level ozone, potentially resulting in crop damage. This mechanism was investigated by comparing two configurations of an atmospheric chemistry-climate model (UM-UKCA) under a 2100 climate following an IPCC scenario of moderate climate change. The first run had a present day crop distribution but isoprene emissions concurrent with 2100 temperatures and climatic conditions. The second run had isoprene emissions representative of both a 2100 climate and a 2100 crop distribution in accordance with the IMAGE model. By comparing these runs it was established that ozone increased by up to 8 ppb (~30%) due to crop land expansion. Over the Amazon (the most affected region) it was found that crops were exposed to a daily maximum 8-hour (DM8H) ozone above the 35 ppb threshold for up to 65 days more per year than in the base case. These conclusions suggest that increasing the crop fraction in current areas of natural rainforest could increase regional ground level ozone, having a significant effect on crop yield and air quality. The sensitivity of such conclusions to isoprene chemistry was examined by varying the isoprene chemistry scheme within the model. The CheT isoprene scheme used here (50 reactions) was compared with the AQUM (23 reactions) and CESM Superfast (2 reactions) isoprene schemes, all of which are currently used in Earth-system models. It was found that the effect of transplanting these isoprene schemes into the base CheT chemistry scheme lead, in both cases, to higher ozone over isoprene rich regions by up to ~40 ppb. Furthermore, upon repeating the land use change experiment with these other isoprene schemes, it was found that the AQUM scheme produced more ozone (up to ~20 ppb more) in isoprene rich regions due to crop expansion than CheT. However the CESM Superfast scheme showed the opposite effect, producing less ozone than the CheT scheme in isoprene-rich regions. These varied responses highlight the sensitivity of future trends in surface ozone to isoprene chemistry within the range of some currently used chemical schemes, and suggest that further research is needed in order to most effectively parameterise this complex chemistry.

Influence of the coating level on the heterogeneous ozonolysis kinetics and product yields of chlorpyrifos ethyl adsorbed on sand particles.

PubMed

El Masri, Ahmad; Laversin, Hélène; Chakir, Abdelkhaleq; Roth, Estelle

2016-12-01

Heterogeneous oxidation of chlorpyrifos ethyl (CLP) coated sand particles by gaseous ozone was studied. Mono-size sand was coated with CLP at different coating levels between 10 and 100 μg g -1 and exposed to ozone. Results were analyzed thanks to Gas Surface Reaction and Surface Layer Reaction Models. Kinetic parameters derived from these models were analyzed and led to several conclusions. The equilibrium constant of O 3 between the gas phase and the CLP-coated sand was independent on the sand contamination level. Ozone seems to have similar affinity for coated or uncoated sand surface. Meanwhile, the kinetic parameters decreased with an increasing coating level. Chlorpyrifos Oxon, (CLPO) has been identified and quantified as an ozonolysis product. The product yield of CLPO remains constant (53 ± 10%) for the different coating level. The key parameter influencing the CLP reactivity towards ozone was the CLP-coating level. This dependence had a great influence on the lifetime of the CLP coated on sand particles, with respect to ozone, which could reach several years at high contamination level. Copyright © 2016 Elsevier Ltd. All rights reserved.

Estimating changes in urban ozone concentrations due to life cycle emissions from hydrogen transportation systems

NASA Astrophysics Data System (ADS)

Wang, Guihua; Ogden, Joan M.; Chang, Daniel P. Y.

Hydrogen has been proposed as a low polluting alternative transportation fuel that could help improve urban air quality. This paper examines the potential impact of introducing a hydrogen-based transportation system on urban ambient ozone concentrations. This paper considers two scenarios, where significant numbers of new hydrogen vehicles are added to a constant number of gasoline vehicles. In our scenarios hydrogen fuel cell vehicles (HFCVs) are introduced in Sacramento, California at market penetrations of 9% and 20%. From a life cycle analysis (LCA) perspective, considering all the emissions involved in producing, transporting, and using hydrogen, this research compares three hypothetical natural gas to hydrogen pathways: (1) on-site hydrogen production; (2) central hydrogen production with pipeline delivery; and (3) central hydrogen production with liquid hydrogen truck delivery. Using a regression model, this research shows that the daily maximum temperature correlates well with atmospheric ozone formation. However, increases in initial VOC and NO x concentrations do not necessarily increase the peak ozone concentration, and may even cause it to decrease. It is found that ozone formation is generally limited by NO x in the summer and is mostly limited by VOC in the fall in Sacramento. Of the three hydrogen pathways, the truck delivery pathway contributes the most to ozone precursor emissions. Ozone precursor emissions from the truck pathway at 9% market penetration can cause additional 3-h average VOC (or NO x) concentrations up to approximately 0.05% (or 1%) of current pollution levels, and at 20% market penetration up to approximately 0.1% (or 2%) of current pollution levels. However, all of the hydrogen pathways would result in very small (either negative or positive) changes in ozone air quality. In some cases they will result in worse ozone air quality (mostly in July, August, and September), and in some cases they will result in better ozone air quality (mostly in October). The truck pathway tends to cause a much wider fluctuation in degradation or improvement of ozone air quality: percentage changes in peak ozone concentrations are approximately -0.01% to 0.04% for the assumed 9% market penetration, and approximately -0.03% to 0.1% for the 20% market penetration. Moreover, the 20% on-site pathway occasionally results in a decrease of about -0.1% of baseline ozone pollution. Compared to the current ambient pollution level, all three hydrogen pathways are unlikely to cause a serious ozone problem for market penetration levels of HFCVs in the 9-20% range.

Effects of Exposure to Ozone on the Ocular Surface in an Experimental Model of Allergic Conjunctivitis

PubMed Central

Lee, Hun; Kim, Eung Kweon; Kim, Hee Young; Kim, Tae-im

2017-01-01

Based on previous findings that ozone can induce an inflammatory response in the ocular surface of an animal model and in cultured human conjunctival epithelial cells, we investigated whether exposure to ozone exacerbates symptoms of allergic conjunctivitis. We evaluated the effects of exposure to ozone on conjunctival chemosis, conjunctival injection, corneal and conjunctival fluorescein staining scores, production of inflammatory cytokines in tears, and aqueous tear production in a mouse model of allergic conjunctivitis. To validate our in vivo results, we used interleukin (IL)-1α-pretreated conjunctival epithelial cells as an in vitro substitute for the mouse model. We evaluated whether exposure to ozone increased the inflammatory response and altered oxidative status and mitochondrial function in IL-1α-pretreated conjunctival epithelial cells. In the in vivo study, ozone induced increases in conjunctival chemosis, conjunctival injection, corneal and conjunctival fluorescein staining scores, and production of inflammatory cytokines, accompanied by a decrease in tear volume. In the in vitro study, exposure to ozone led to additional increases in IL-6 and tumor necrosis factor-α mRNA levels, which were already induced by treatment with IL-1α. Ozone did not induce any changes in cell viability. Pretreatment with IL-1α increased the expression of manganese superoxide dismutase, and exposure to ozone led to additional increments in the expression of this antioxidant enzyme. Ozone did not induce any changes in mitochondrial activity or expression of mitochondrial enzymes and proteins related to mitochondrial function, with the exception of phosphor-mammalian target of rapamycin. Treatment with butylated hydroxyanisole, a free radical scavenger, attenuated the ozone-induced increases in IL-6 expression in IL-1α-pretreated conjunctival epithelial cells. Therefore, we conclude that exposure to ozone exacerbates the detrimental effects on the integrity of the ocular surface caused by conjunctival allergic reactions, and further increases the inflammatory response in IL-1α-pretreated conjunctival epithelial cells. PMID:28046113

Ozone concentrations at a selected high-elevation forest site downwind Mexico City

NASA Astrophysics Data System (ADS)

Torres-JArdon, R.

2013-05-01

Torres-Jardón, R.*, Rosas-Pérez, I., Granada-Macías, L. M., Ruiz-Suárez, L. G. Centro de Ciencias de la Atmósfera, UNAM, México D. F. México * rtorres@unam.mx For many years, the vegetation of forest species such as Abies religiosa in natural parks located in the southwest mountains of Mexico City has attracted much attention since these parks have been experiencing a severe decline of unclear etiology. The high ozone levels in the area and the observed naked eye macroscopic, histological and cytological injuries on these species, strongly suggest an important contribution of tropospheric ozone to this deterioration process. Apart of historical short monitoring campaigns for measuring ozone levels in these mountains, it is known just a little is known about the present exposure levels at which the local vegetation is exposed. A continuous ozone analyzer has been in operation since 2011 at a high-elevation forest site (Parque Nacional Miguel Hidalgo, PNMH; 3110 m above mean sea level) located downwind of Mexico City Metropolitan Area (MCMA), in order to characterize the local ozone diel amplitude and its seasonal trend, as well as the influence of MCMA on the local O3 concentrations. Hourly average ozone data in PNMH shows that in general, the diel of ozone concentrations in the forest site has a statistical significant correlation with the pattern of ozone levels observed in several monitoring sites (smog receptor sites) within the MCMA, although the high elevation O3 levels are relatively lower than those in the urban area (around 2200 m above mean sea level). It is possible that a part of the oxidants in the air masses are removed by sink deposition processes during the air mass transport across the hills. The diel amplitude of ozone concentrations is small in the cold season, increasing as the seasons advance to June. As in the city, the highest ozone concentrations occur in April or May and the lowest levels during the rainy season, which extends from July to September. Episodes of high concentrations occurred mainly during the dry warm months. Most of the year, nocturnal ozone levels were higher than those registered in the urban area due to the PMH altitude. As a great part of the mountain terrain regularly is above the nocturnal mixing layer formed each day on the valley floor, the ozone remanent levels above this layer in the mountains are kept isolated from urban NOx emissions generated at night. An evaluation of the AOT40 indicator shows that the forest zone is under a strong risk due to ozone pollution. A preliminary analysis of several ozone events in the PNMH shows the suppression of the diel peak, suggesting that a stratospheric intrusion of ozone occurs frequently in high-elevation sites surrounding MCMA.

Impacts of interstate transport of pollutants on high ozone events over the Mid-Atlantic United States

NASA Astrophysics Data System (ADS)

Liao, Kuo-Jen; Hou, Xiangting; Baker, Debra Ratterman

2014-02-01

The impacts of interstate transport of anthropogenic nitrogen oxides (NOx) and volatile organic compound (VOC) emissions on peak ozone formation in four nonattainment areas (i.e., Baltimore, Philadelphia-Wilmington-Atlantic City, Pittsburgh-Beaver Valley and Washington, DC) in the Mid-Atlantic U.S. were quantified in this study. Regional air quality and sensitivities of ground-level ozone to emissions from four regions in the eastern U.S. were simulated for three summer months (June, July and August) in 2007 using the U.S. EPA's Community Multiscale Air Quality model with the decoupled direct method 3D. The emissions inventory used in this study was the 2007 Mid-Atlantic Regional Air Management Association Level 2 inventory, developed for State Implementation Plan screening modeling for the Ozone Transport Commission region. The modeling results show that responses of peak ozone levels at specific locations to emissions from EGU (i.e., electric generating unit) and non-EGU sources could be different. Therefore, emissions from EGU and non-EGU sources should be considered as two different control categories when developing regional air pollution mitigation strategies. Based on the emission inventories used in this study, reductions in anthropogenic NOx emissions (including those from EGU and non-EGU sources) from the Great Lake region as well as northeastern and southeastern U.S. would be effective for decreasing area-mean peak ozone concentrations during the summer of 2007 in the Mid-Atlantic ozone air quality nonattainment areas. The results also show that reductions in anthropogenic VOC emissions from the northeastern U.S. would also be effective for decreasing area-mean peak ozone concentrations over the Mid-Atlantic U.S. In some cases, reductions in anthropogenic NOx emissions from the Great Lake and northeastern U.S. could slightly increase area-mean peak ozone concentrations at some ozone monitors in the Pittsburgh-Beaver Valley and Washington, DC areas. However, the disbenefit of the slight increase in ozone concentrations attributed to the NOx emission controls was far outweighed by the overall ozone air quality benefits over the Mid-Atlantic region.

Exposure to Ozone Modulates Human Airway Protease/Antiprotease Balance Contributing to Increased Influenza A Infection

PubMed Central

Kesic, Matthew J.; Meyer, Megan; Bauer, Rebecca; Jaspers, Ilona

2012-01-01

Exposure to oxidant air pollution is associated with increased respiratory morbidities and susceptibility to infections. Ozone is a commonly encountered oxidant air pollutant, yet its effects on influenza infections in humans are not known. The greater Mexico City area was the primary site for the spring 2009 influenza A H1N1 pandemic, which also coincided with high levels of environmental ozone. Proteolytic cleavage of the viral membrane protein hemagglutinin (HA) is essential for influenza virus infectivity. Recent studies suggest that HA cleavage might be cell-associated and facilitated by the type II transmembrane serine proteases (TTSPs) human airway trypsin-like protease (HAT) and transmembrane protease, serine 2 (TMPRSS2), whose activities are regulated by antiproteases, such as secretory leukocyte protease inhibitor (SLPI). Based on these observations, we sought to determine how acute exposure to ozone may modulate cellular protease/antiprotease expression and function, and to define their roles in a viral infection. We utilized our in vitro model of differentiated human nasal epithelial cells (NECs) to determine the effects of ozone on influenza cleavage, entry, and replication. We show that ozone exposure disrupts the protease/antiprotease balance within the airway liquid. We also determined that functional forms of HAT, TMPRSS2, and SLPI are secreted from human airway epithelium, and acute exposure to ozone inversely alters their expression levels. We also show that addition of antioxidants significantly reduces virus replication through the induction of SLPI. In addition, we determined that ozone-induced cleavage of the viral HA protein is not cell-associated and that secreted endogenous proteases are sufficient to activate HA leading to a significant increase in viral replication. Our data indicate that pre-exposure to ozone disrupts the protease/antiprotease balance found in the human airway, leading to increased influenza susceptibility. PMID:22496898

Impact of natural gas development in the Marcellus and Utica shales on regional ozone and fine particulate matter levels

NASA Astrophysics Data System (ADS)

Roohani, Yusuf H.; Roy, Anirban A.; Heo, Jinhyok; Robinson, Allen L.; Adams, Peter J.

2017-04-01

The Marcellus and Utica shale formations have recently been the focus of intense natural gas development and production, increasing regional air pollutant emissions. Here we examine the effects of these emissions on regional ozone and fine particulate matter (PM2.5) levels using the chemical transport model, CAMx, and estimate the public health costs with BenMAP. Simulations were performed for three emissions scenarios for the year 2020 that span a range potential development storylines. In areas with the most gas development, the 'Medium Emissions' scenario, which corresponds to an intermediate level of development and widespread adoption of new equipment with lower emissions, is predicted to increase 8-hourly ozone design values by up to 2.5 ppbv and average annual PM2.5 concentrations by as much as 0.27 μg/m3. These impacts could range from as much as a factor of two higher to a factor of three lower depending on the level of development and the adoption of emission controls. Smaller impacts (e.g. 0.1-0.5 ppbv of ozone, depending on the emissions scenario) are predicted for non-attainment areas located downwind of the Marcellus region such as New York City, Philadelphia and Washington, DC. Premature deaths for the 'Medium Emissions' scenario are predicted to increase by 200-460 annually. The health impacts as well as the changes in ozone and PM2.5 were all driven primarily by NOx emissions.

Potential impact of climate change on air pollution-related human health effects.

PubMed

Tagaris, Efthimios; Liao, Kuo-Jen; Delucia, Anthony J; Deck, Leland; Amar, Praveen; Russell, Armistead G

2009-07-01

The potential health impact of ambient ozone and PM2.5 concentrations modulated by climate change over the United States is investigated using combined atmospheric and health modeling. Regional air quality modeling for 2001 and 2050 was conducted using CMAQ Modeling System with meteorology from the GISS Global Climate Model, downscaled regionally using MM5,keeping boundary conditions of air pollutants, emission sources, population, activity levels, and pollution controls constant. BenMap was employed to estimate the air pollution health outcomes at the county, state, and national level for 2050 caused by the effect of meteorology on future ozone and PM2.5 concentrations. The changes in calculated annual mean PM2.5 concentrations show a relatively modest change with positive and negative responses (increasing PM2.5 levels across the northeastern U.S.) although average ozone levels slightly decrease across the northern sections of the U.S., and increase across the southern tier. Results suggest that climate change driven air quality-related health effects will be adversely affected in more then 2/3 of the continental U.S. Changes in health effects induced by PM2.5 dominate compared to those caused by ozone. PM2.5-induced premature mortality is about 15 times higher then that due to ozone. Nationally the analysis suggests approximately 4000 additional annual premature deaths due to climate change impacts on PM2.5 vs 300 due to climate change-induced ozone changes. However, the impacts vary spatially. Increased premature mortality due to elevated ozone concentrations will be offset by lower mortality from reductions in PM2.5 in 11 states. Uncertainties related to different emissions projections used to simulate future climate, and the uncertainties forecasting the meteorology, are large although there are potentially important unaddressed uncertainties (e.g., downscaling, speciation, interaction, exposure, and concentration-response function of the human health studies).

Analysis of atmospheric ozone measurements made from a B-747 airliner during March 1975

NASA Technical Reports Server (NTRS)

Holdeman, J. D.; Falconer, P. D.

1976-01-01

Measurements of atmospheric ozone in the upper troposphere and lower stratosphere made during March 1975 as part of the NASA Global Atmospheric Sampling Program are reported and analyzed. The interrelationships between the ozone mixing ratio and geographical and meteorological parameters are examined in several case studies. The ozone data correlate well with the difference between the flight altitude and the height of the tropopause, as obtained from National Meteorological Center gridded data. The distribution of ozone mixing ratios with latitude at an altitude of 11 + or - 0.5 km shows a poleward increase and large variability at latitudes greater than 30 deg N in agreement with published mean ozone levels from the North American ozone sonde network.

The Sensitivity of U.S. Surface Ozone Formation to NOx, and VOCs as Viewed from Space

NASA Technical Reports Server (NTRS)

Duncan, Bryan N.; Yoshida, Yasuko; Sillman, Sanford; Retscher, Christian; Pickering, Kenneth E.; Martin, Randall V.; Celarier, Edward A.

2009-01-01

We investigated variations in the sensitivity of surface ozone formation in summer to precursor species concentrations of volatile organic compounds (VOCs) and nitrogen oxides (NO(x)) as inferred from the ratio of tropospheric columns of formaldehyde and nitrogen dioxide from the Aura Ozone Monitoring Instrument (OMI). The data indicate that ozone formation became: 1. more sensitive to NO(x) over most of the U.S, from 2005 to 2007 because of substantial decreases in NO(x) emissions primarily from stationary sources, and 2. more sensitive to NO(x) with increasing temperature, in part because emissions of highly reactive, biogenic isoprene increase with temperature, thus increasing the total VOC reactivity. Based on our interpretation of the data, current strategies implemented to reduce unhealthy levels of surface ozone should focus more on reducing NO(x) emissions, except in some downtown areas which have historically benefited from reductions in VOC emissions.

Investigation of the influence of transport from oil and natural gas regions on elevated ozone levels in the northern Colorado front range.

PubMed

Evans, Jason M; Helmig, Detlev

2017-02-01

The Northern Colorado Front Range (NCFR) has been in exceedance of the ozone National Ambient Air Quality Standard (NAAQS) since 2004, which has led to much debate over the sources of ozone precursors to the region, as this area is home to both the Denver, CO, metropolitan area and the Denver-Julesburg Basin, which has experienced rapid growth of oil and natural gas (O&NG) operations and associated emissions. Several recent studies have reported elevated levels of atmospheric volatile organic compounds (VOCs) as a result of O&NG emissions and the potential for significant ozone production from these emissions, despite implementation of stricter O&NG VOC emissions regulations in 2008. Approximately 88% of 1-hr elevated ozone events (>75 ppbv) occur during June-August, indicating that elevated ozone levels are driven by regional photochemistry. Analyses of surface ozone and wind observations from two sites, namely, South Boulder and the Boulder Atmospheric Observatory, both near Boulder, CO, show a preponderance of elevated ozone events associated with east-to-west airflow from regions with O&NG operations in the N-ESE, and a relatively minor contribution of transport from the Denver Metropolitan area to the SE-S. Transport from upwind areas associated with abundant O&NG operations accounts for on the order of 65% (mean for both sites) of 1-hr averaged elevated ozone levels, while the Denver urban corridor accounts for 9%. These correlations contribute to mounting evidence that air transport from areas with O&NG operation has a significant impact on ozone and air quality in the NCFR. This article builds on several previous pieces of research that implied significant contributions from oil and natural gas emissions on ozone production in the Northern Colorado Front Range. By correlating increased ozone events with transport analyses we show that there is a high abundance of transport events with elevated ozone originating from the Denver-Julesburg oil and natural gas basin. These findings will help air quality regulators to better assess contributing sources to ozone production and in directing policies to curb ozone pollution in this region.

Accumulation of secondary metabolites in healthy and diseased barley, grown under future climate levels of CO2, ozone and temperature.

PubMed

Mikkelsen, B L; Olsen, C E; Lyngkjær, M F

2015-10-01

Plants produce secondary metabolites promoting adaptation to changes in the environment and challenges by pathogenic microorganisms. A future climate with increased temperature and CO2 and ozone levels will likely alter the chemical composition of plants and thereby plant-pathogen interactions. To investigate this, barley was grown at elevated CO2, temperature and ozone levels as single factors or in combination resembling future climatic conditions. Increased basal resistance to the powdery mildew fungus was observed when barley was grown under elevated CO2, temperature and ozone as single factors. However, this effect was neutralized in the combination treatments. Twenty-five secondary metabolites were putatively identified in healthy and diseased barley leaves, including phenylpropanoids, phenolamides and hydroxynitrile glucosides. Accumulation of the compounds was affected by the climatic growth conditions. Especially elevated temperature, but also ozone, showed a strong impact on accumulation of many compounds, suggesting that these metabolites play a role in adaptation to unfavorable growth conditions. Many compounds were found to increase in powdery mildew diseased leaves, in correlation with a strong and specific influence of the climatic growth conditions. The observed disease phenotypes could not be explained by accumulation of single compounds. However, decreased accumulation of the powdery mildew associated defense compound p-coumaroylhydroxyagmatine could be implicated in the increased disease susceptibility observed when barley was grown under combination of elevated CO2, temperature and ozone. The accumulation pattern of the compounds in both healthy and diseased leaves from barley grown in the combination treatments could not be deduced from the individual single factor treatments. This highlights the complex role and regulation of secondary metabolites in plants' adaptation to unfavorable growth conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Air pollution alters brain and pituitary endothelin-1 and inducible nitric oxide synthase gene expression.

PubMed

Thomson, Errol M; Kumarathasan, Prem; Calderón-Garcidueñas, Lilian; Vincent, Renaud

2007-10-01

Recent work suggests that air pollution is a risk factor for cerebrovascular and neurodegenerative disease. Effects of inhaled pollutants on the production of vasoactive factors such as endothelin (ET) and nitric oxide (NO) in the brain may be relevant to disease pathogenesis. Inhaled pollutants increase circulating levels of ET-1 and ET-3, and the pituitary is a potential source of plasma ET, but the effects of pollutants on the expression of ET and NO synthase genes in the brain and pituitary are not known. In the present study, Fischer-344 rats were exposed by nose-only inhalation to particles (0, 5, 50mg/m3 EHC-93), ozone (0, 0.4, 0.8 ppm), or combinations of particles and ozone for 4 h. Real-time reverse transcription polymerase chain reaction was used to measure mRNA levels in the cerebral hemisphere and pituitary 0 and 24 h post-exposure. Ozone inhalation significantly increased preproET-1 but decreased preproET-3 mRNAs in the cerebral hemisphere, while increasing mRNA levels of preproET-1, preproET-3, and the ET-converting enzyme (ECE)-1 in the pituitary. Inducible NO synthase (iNOS) was initially decreased in the cerebral hemisphere after ozone inhalation, but increased 24 h post-exposure. Particles decreased tumour necrosis factor (TNF)-alpha mRNA in the cerebral hemisphere, and both particles and ozone decreased TNF-alpha mRNA in the pituitary. Our results show that ozone and particulate matter rapidly modulate the expression of genes involved in key vasoregulatory pathways in the brain and pituitary, substantiating the notion that inhaled pollutants induce cerebrovascular effects.

Medical ozone therapy reduces oxidative stress and testicular damage in an experimental model of testicular torsion in rats.

PubMed

Tusat, Mustafa; Mentese, Ahmet; Demir, Selim; Alver, Ahmet; Imamoglu, Mustafa

2017-01-01

Testicular torsion (TT) refers to rotation of the testis and twisting of the spermatic cord. TT results in ischemia-reperfusion (I/R) injury involving increased oxidative stress, inflammation and apoptosis, and can even lead to infertility. The aim of this study was to investigate the effect of ozone therapy on testicular damage due to I/R injury in an experimental torsion model. 24 male Sprague-Dawley rats were divided into 3 groups; sham-operated, torsion/detorsion (T/D), and T/D+ozone. Ozone (1mg/kg) was injected intraperi-toneally 120 minutes before detorsion and for the following 24h. Blood and tissue samples were collected at the end of 24h. Johnsen score, ischemia modified albumin (IMA), total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) levels were determined. Levels of IMA, TOS, OSI, and histopathological scores increased in the serum/tissue of the rats in the experimental T/D group. Serum IMA, TOS, and OSI levels and tissue histo-pathological scores were lower in the rats treated with ozone compared with the T/D group. Our study results suggest that ozone therapy may exhibit beneficial effects on both biochemical and histopathological findings. Clinical trials are now necessary to confirm this. Copyright® by the International Brazilian Journal of Urology.

Spatial distribution of tropospheric ozone in western Washington, USA

USGS Publications Warehouse

Cooper, S.M.; Peterson, D.L.

2000-01-01

We quantified the distribution of tropospheric ozone in topographically complex western Washington state, USA (total area a??6000 km2), using passive ozone samplers along nine river drainages to measure ozone exposure from near sea level to high-elevation mountain sites. Weekly average ozone concentrations were higher with increasing distance from the urban core and at higher elevations, increasing a mean of 1.3 ppbv per 100 m elevation gain for all mountain transects. Weekly average ozone concentrations were generally highest in Cascade Mountains drainages east and southeast of Seattle (maximum=55a??67 pbv) and in the Columbia River Gorge east of Portland (maximum=59 ppbv), and lowest in the western Olympic Peninsula (maximum=34 ppbv). Higher ozone concentrations in the Cascade Mountains and Columbia River locations downwind of large cities indicate that significant quantities of ozone and ozone precursors are being transported eastward toward rural wildland areas by prevailing westerly winds. In addition, temporal (week to week) variation in ozone distribution is synchronous within and between all drainages sampled, which indicates that there is regional coherence in air pollution detectable with weekly averages. These data provide insight on large-scale spatial variation of ozone distribution in western Washington, and will help regulatory agencies optimize future monitoring networks and identify locations where human health and natural resources could be at risk.

Ozone reaction with clothing and its initiated VOC emissions in an environmental chamber.

PubMed

Rai, A C; Guo, B; Lin, C-H; Zhang, J; Pei, J; Chen, Q

2014-02-01

Human health is adversely affected by ozone and the volatile organic compounds (VOCs) produced from its reactions in the indoor environment. Hence, it is important to characterize the ozone-initiated reactive chemistry under indoor conditions and study the influence of different factors on these reactions. This investigation studied the ozone reactions with clothing through a series of experiments conducted in an environmental chamber under various conditions. The study found that the ozone reactions with a soiled (human-worn) T-shirt consumed ozone and generated VOCs. The ozone removal rate and deposition velocity for the T-shirt increased with the increasing soiling level and air change rate, decreased at high ozone concentrations, and were relatively unaffected by the humidity. The deposition velocity for the soiled T-shirt ranged from 0.15 to 0.29 cm/s. The ozone-initiated VOC emissions included C6-C10 straight-chain saturated aldehydes, acetone, and 4-OPA (4-oxopentanal). The VOC emissions were generally higher at higher ozone, humidity, soiling of T-shirt, and air change rate. The total molar yield was approximately 0.5 in most cases, which means that for every two moles of ozone removed by the T-shirt surface, one mole of VOCs was produced. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Rapid increase in atmospheric iodine levels in the North Atlantic since the mid-20th century.

PubMed

Cuevas, Carlos A; Maffezzoli, Niccolò; Corella, Juan Pablo; Spolaor, Andrea; Vallelonga, Paul; Kjær, Helle A; Simonsen, Marius; Winstrup, Mai; Vinther, Bo; Horvat, Christopher; Fernandez, Rafael P; Kinnison, Douglas; Lamarque, Jean-François; Barbante, Carlo; Saiz-Lopez, Alfonso

2018-04-13

Atmospheric iodine causes tropospheric ozone depletion and aerosol formation, both of which have significant climate impacts, and is an essential dietary element for humans. However, the evolution of atmospheric iodine levels at decadal and centennial scales is unknown. Here, we report iodine concentrations in the RECAP ice-core (coastal East Greenland) to investigate how atmospheric iodine levels in the North Atlantic have evolved over the past 260 years (1750-2011), this being the longest record of atmospheric iodine in the Northern Hemisphere. The levels of iodine tripled from 1950 to 2010. Our results suggest that this increase is driven by anthropogenic ozone pollution and enhanced sub-ice phytoplankton production associated with the recent thinning of Arctic sea ice. Increasing atmospheric iodine has accelerated ozone loss and has considerably enhanced iodine transport and deposition to the Northern Hemisphere continents. Future climate and anthropogenic forcing may continue to amplify oceanic iodine emissions with potentially significant health and environmental impacts at global scale.

Impact of iodine chemistry on coastal ozone levels at the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Tuite, K.; Stutz, J.; Brockway, N.; Colosimo, S. F.; Tsai, J. Y.; Grossmann, K.; Alvarez, S. L.; Flynn, J. H., III; Erickson, M.; Caicedo, V.; Griffin, R. J.; Wallace, H. W., IV; Schulze, B.; Sheesley, R. J.; Usenko, S.; Yarwood, G.; Nopmongcol, U.

2016-12-01

Reactive iodine (Ix = I + IO) is known to destroy ozone through catalytic cycles in the marine boundary layer (MBL) and can thus have a significant impact on tropospheric ozone in coastal regions. As air quality standards for ozone become stricter, accurate background levels are increasingly important for the development of ozone reduction strategies. The Texas Gulf coast is an example for the significance of MBL background ozone, as onshore flows from the Gulf of Mexico contribute to the ozone levels in Houston and other coastal areas. The Gulf coast often experiences ozone mixing ratios below 20 ppb during summer onshore flow conditions, which are currently overestimated by regional and global air quality models. Modeling with the Comprehensive Air quality Model with extensions (CAMx) and GEOS-Chem including halogen chemistry identified iodine emissions from the Gulf of Mexico as a possible explanation. However, ambient measurements of Ix species for the Gulf of Mexico are needed to test this hypothesis and, if confirmed, refine models. We measured IO, O3, and other trace gases at the Gulf coast near Galveston, TX, using UCLA's long path DOAS instrument and a suite of in-situ instruments. During the study period from May 15 through July 12, 2016, several multi-day events with MBL ozone levels below 20 ppb were encountered. Here we present the observational data with a focus on time periods with onshore flow from the Gulf. A chemical steady state analysis will be used to assess whether the observed Ix mixing ratios can explain these low ozone mixing ratios. Our results will be compared to the CAMx and GEOS-Chem model simulations.

Impact of increasing heat waves on U.S. ozone episodes in the 2050s: Results from a multimodel analysis using extreme value theory

NASA Astrophysics Data System (ADS)

Shen, L.; Mickley, L. J.; Gilleland, E.

2016-04-01

We develop a statistical model using extreme value theory to estimate the 2000-2050 changes in ozone episodes across the United States. We model the relationships between daily maximum temperature (Tmax) and maximum daily 8 h average (MDA8) ozone in May-September over 2003-2012 using a Point Process (PP) model. At ~20% of the sites, a marked decrease in the ozone-temperature slope occurs at high temperatures, defined as ozone suppression. The PP model sometimes fails to capture ozone-Tmax relationships, so we refit the ozone-Tmax slope using logistic regression and a generalized Pareto distribution model. We then apply the resulting hybrid-extreme value theory model to projections of Tmax from an ensemble of downscaled climate models. Assuming constant anthropogenic emissions at the present level, we find an average increase of 2.3 d a-1 in ozone episodes (>75 ppbv) across the United States by the 2050s, with a change of +3-9 d a-1 at many sites.

Impact of parameterization choices on the restitution of ozone deposition over vegetation

NASA Astrophysics Data System (ADS)

Le Morvan-Quéméner, Aurélie; Coll, Isabelle; Kammer, Julien; Lamaud, Eric; Loubet, Benjamin; Personne, Erwan; Stella, Patrick

2018-04-01

Ozone is a potentially phyto-toxic air pollutant, which can cause leaf damage and drastically alter crop yields, causing serious economic losses around the world. The VULNOZ (VULNerability to OZone in Anthropised Ecosystems) project is a biology and modeling project that aims to understand how plants respond to the stress of high ozone concentrations, then use a set of models to (i) predict the impact of ozone on plant growth, (ii) represent ozone deposition fluxes to vegetation, and finally (iii) estimate the economic consequences of an increasing ozone background the future. In this work, as part of the VULNOZ project, an innovative representation of ozone deposition to vegetation was developed and implemented in the CHIMERE regional chemistry-transport model. This type of model calculates the average amount of ozone deposited on a parcel each hour, as well as the integrated amount of ozone deposited to the surface at the regional or country level. Our new approach was based on a refinement of the representation of crop types in the model and the use of empirical parameters specific to each crop category. The results obtained were compared with a conventional ozone deposition modeling approach, and evaluated against observations from several agricultural areas in France. They showed that a better representation of the distribution between stomatal and non-stomatal ozone fluxes was obtained in the empirical approach, and they allowed us to produce a new estimate of the total amount of ozone deposited on the subtypes of vegetation at the national level.

The maintenance of elevated active chlorine levels in the Antarctic lower stratosphere through HCl null cycles

NASA Astrophysics Data System (ADS)

Müller, Rolf; Grooß, Jens-Uwe; Mannan Zafar, Abdul; Robrecht, Sabine; Lehmann, Ralph

2018-03-01

The Antarctic ozone hole arises from ozone destruction driven by elevated levels of ozone destroying (active) chlorine in Antarctic spring. These elevated levels of active chlorine have to be formed first and then maintained throughout the period of ozone destruction. It is a matter of debate how this maintenance of active chlorine is brought about in Antarctic spring, when the rate of formation of HCl (considered to be the main chlorine deactivation mechanism in Antarctica) is extremely high. Here we show that in the heart of the ozone hole (16-18 km or 85-55 hPa, in the core of the vortex), high levels of active chlorine are maintained by effective chemical cycles (referred to as HCl null cycles hereafter). In these cycles, the formation of HCl is balanced by immediate reactivation, i.e. by immediate reformation of active chlorine. Under these conditions, polar stratospheric clouds sequester HNO3 and thereby cause NO2 concentrations to be low. These HCl null cycles allow active chlorine levels to be maintained in the Antarctic lower stratosphere and thus rapid ozone destruction to occur. For the observed almost complete activation of stratospheric chlorine in the lower stratosphere, the heterogeneous reaction HCl + HOCl is essential; the production of HOCl occurs via HO2 + ClO, with the HO2 resulting from CH2O photolysis. These results are important for assessing the impact of changes of the future stratospheric composition on the recovery of the ozone hole. Our simulations indicate that, in the lower stratosphere, future increased methane concentrations will not lead to enhanced chlorine deactivation (through the reaction CH4 + Cl → HCl + CH3) and that extreme ozone destruction to levels below ≈ 0.1 ppm will occur until mid-century.

Spatial patterns of tropospheric ozone in the mount rainier region of the cascade mountains, USA

NASA Astrophysics Data System (ADS)

Brace, Sarah; Peterson, David L.

Few data exist on tropospheric ozone concentrations in rural and wildland areas of western Washington, U.S.A. We measured tropospheric ozone in Mount Rainier National Park and the Puget Sound region of Washington using electronic analyzers and passive samplers during the summers of 1994 and 1995. Electronic analyzers recorded hourly ozone concentrations from five locations between Seattle and Mount Rainier. Ozone concentrations generally increased with distance from Seattle, with maximum hourly concentrations recorded at Enumclaw (319 m elevation, 50 km SE of Seattle). Paradise (1650 m elevation, 100 km SE of Seattle) had the highest monthly mean concentration of all sites measured with analyzers. Diurnal patterns on high-ozone days indicate that concentrations at Paradise remain near 60 ppbv throughout the day, whereas ozone concentrations closer to Seattle had higher peaks during the afternoon but dropped to near zero at night. Passive ozone samplers were used to measure weekly average ozone exposures in four river drainages within Mount Rainier National Park, across an elevation gradient (420 -2100 m). In most drainages, ozone levels increased with elevation, with highest average weekly ozone exposure (47 ppbv) recorded at 2100 m. Ozone concentrations are significantly higher in the western portion of the park, indicating that ozone exposure varies considerably over short distances. These data provide a reference point for air quality in western Washington and indicate that intensive sampling is necessary to quantify spatial patterns of tropospheric ozone in mountainous regions.

Spatial patterns of tropospheric ozone in the Mount Rainier region of the Cascade Mountains, USA

USGS Publications Warehouse

Brace, S.; Peterson, D.L.

1998-01-01

Few data exist on tropospheric ozone concentrations in rural and wildland areas of western Washington, U.S.A. We measured tropospheric ozone in Mount Rainier National Park and the Puget Sound region of Washington using electronic analyzers and passive samplers during the summers of 1994 and 1995. Electronic analyzers recorded hourly ozone concentrations from five locations between Seattle and Mount Rainier. Ozone concentrations generally increased with distance from Seattle, with maximum hourly concentrations recorded at Enumclaw (319 m elevation, 50 km SE of Seattle). Paradise (1650 m elevation, 100 km SE of Seattle) had the highest monthly mean concentration of all sites measured with analyzers. Diurnal patterns on high-ozone days indicate that concentrations at Paradise remain near 60 ppbv throughout the day, whereas ozone concentrations closer to Seattle had higher peaks during the afternoon but dropped to near zero at night. Passive ozone samplers were used to measure weekly average ozone exposures in four river drainages within Mount Rainier National Park, across an elevation gradient (420 a??2100 m). In most drainages, ozone levels increased with elevation, with highest average weekly ozone exposure (47 ppbv) recorded at 2100 m. Ozone concentrations are significantly higher in the western portion of the park, indicating that ozone exposure varies considerably over short distances. These data provide a reference point for air quality in western Washington and indicate that intensive sampling is necessary to quantify spatial patterns of tropospheric ozone in mountainous regions.

The Effects of Volcano-Induced Ozone Depletion on Short-lived Climate Forcing in the Arctic

NASA Astrophysics Data System (ADS)

Ward, P. L.

2012-12-01

Photodissociation of oxygen maintains the stratopause ~50°C warmer than the tropopause. Photodissociation of ozone warms the lower stratosphere, preventing most of this high-energy DNA-damaging solar radiation from reaching the troposphere. Ozone depletion allows more UV energy to reach the lower troposphere causing photodissociation of anthropogenic ozone and nitrogen dioxide. UV energy also penetrates the ocean >10 m where it is absorbed more efficiently than infrared radiation that barely penetrates the surface. Manmade chlorofluorocarbons caused ozone depletion from 1965 to 1994 with slow recovery predicted over the next 50+ years. But the lowest levels of ozone followed the eruptions of Pinatubo (1991 VEI=6), Eyjafjallajökull (2010 VEI=4), and Grímsvötn (2011 VEI=4). Each of the relatively small, basaltic eruptions in Iceland caused more ozone depletion than the long-term effects of chlorofluorocarbons, although total ozone appears to return to pre-eruption levels within a decade. Ozone depletion by 20% increases energy flux thru the lowermost troposphere by 0.7 W m-2 for overhead sun causing temperatures in the lower stratosphere to drop >2°C since 1958 in steps after the 3 largest volcanic eruptions: Agung 1963, El Chichón 1982, and Pinatubo. Temperatures at the surface increased primarily in the regions and at the times of the greatest observed ozone depletion. The greatest warming observed was along the Western Antarctic Peninsula (65.4°S) where minimum temperatures rose 6.7°C from 1951 to 2003 while maximum temperatures remained relatively constant. Minimum total column ozone in September-October was 40-56% lower than in 1972 almost every year since 1987, strongly anti-correlated with observed minimum temperatures. Sea ice decreased 10%, 7 ice shelves separated, 87% of the glaciers retreated and the Antarctic Circumpolar Current warmed. Elsewhere under the ozone hole, warming of continental Antarctica was limited by the high albedo (0.86) of Antarctic snow and decreasing solar zenith angles at higher latitudes. The second largest ozone depletion was in the Arctic at the times and places of greatest winter warming. Average ozone at four stations in Canada (43-59°N) compared to the 1961-1970 mean were 6% lower in December 2010 after the eruption of Eyjafjallajökull and 11% lower in December 2011 after the eruption of Grímsvötn. In 2012, ozone levels were still 10% lower in March and 7% lower in July. The regions and timing of this depletion are the regions and times of unusually warm temperatures and drought in North America during 2011-2012. The Dust Bowl droughts in 1934 and 1936 show a similar temporal relationship to a highly unusual sequence of five VEI=4-5 eruptions around the Pacific in 1931-1933. Major increases in global pollution were from 1950-1970 while ozone-destroying tropospheric chlorine rose from 1970 to 1994, along with ocean heat content and mean temperature. Pollution does not seem to cause an increase in warming until ozone depletion allows more UV into the lower troposphere. Pollutants decrease surface solar radiation but also reduce Arctic-snow albedo. Widespread observations imply that ozone depletion and associated photodissociation cause substantial warming. Several issues regarding the microphysics of absorption and radiation by greenhouse gases must be resolved before we can quantify their relative importance.

Convection links biomass burning to increased tropical ozone: However, models will tend to overpredict O3

NASA Astrophysics Data System (ADS)

Chatfield, Robert B.; Delany, Anthony C.

1990-10-01

Biomass burning throughout the inhabited portions of the tropics generates precursors which lead to significant local atmospheric ozone pollution. Several simulations show how this smog could be only an easily observed, local manifestation of a much broader increase in tropospheric ozone. We illustrate basic processes with a one-dimensional time-dependent model that is closer to true meteorological motions than commonly used eddy diffusion models. Its application to a representative region of South America gives reasonable simulations of the local pollutants measured there. Three illustrative simulations indicate the importance of dilution, principally due to vertical transport, in increasing the efficiency of ozone production, possibly enough for high ozone to be apparent on a very large, intercontinental scale. In the first, cook-then-mix, simulation the nitrogen oxides and other burning-produced pollutants are confined to a persistently subsident fair weather boundary layer for several days, and the resultant ozone is found to have only a transient influence on the whole column of tropospheric ozone. In the second, mix-then-cook, simulation the effect of typical cumulonimbus convection, which vents an actively polluted boundary layer, is to make a persistent increase in the tropical ozone column. Such a broadly increased ozone column is observed over the the populated "continental" portion of the tropics. A third simulation averages all emission, transport, and deposition parameters, representing one column in a global tropospheric model that does not simulate individual weather events. This "oversmoothing" simulation produces 60% more ozone than observed or otherwise modeled. Qualitatively similar overprediction is suggested for all models which average significantly in time or space, as all need do. Clearly, simulating these O3 levels will depend sensitively on knowledge of the timing of emissions and transport.

Ozone Inhalation Leads to a Dose-Dependent Increase of Cytogenetic Damage in Human Lymphocytes

PubMed Central

Holland, Nina; Davé, Veronica; Venkat, Subha; Wong, Hofer; Donde, Aneesh; Balmes, John R; Arjomandi, Mehrdad

2014-01-01

Ozone is an important constituent of ambient air pollution and represents a major public health concern. Oxidative injury due to ozone inhalation causes the generation of reactive oxygen species and can be genotoxic. To determine whether ozone exposure causes genetic damage in peripheral blood lymphocytes, we employed a well-validated cytokinesis-block micronucleus Cytome assay. Frequencies of micronuclei (MN) and nucleoplasmic bridges (NB) were used as indicators of cytogenetic damage. Samples were obtained from 22 non-smoking healthy subjects immediately before and 24-hr after controlled 4-hr exposures to filtered air, 100 ppb, and 200 ppb ozone while exercising in a repeated-measure study design. Inhalation of ozone at different exposure levels was associated with a significant dose-dependent increase in MN frequency (P < 0.0001) and in the number of cells with more than 1 MN per cell (P < 0.0005). Inhalation of ozone also caused an increase in the number of apoptotic cells (P = 0.002). Airway neutrophilia was associated with an increase in MN frequency (P = 0.033) independent of the direct effects of ozone exposure (P < 0.0001). We also observed significant increases in both MN and NB frequencies after exercise in filtered air, suggesting that physical activity is also an important inducer of oxidative stress. These results corroborate our previous findings that cytogenetic damage is associated with ozone exposure, and show that damage is dose-dependent. Further study of ozone-induced cytogenetic damage in airway epithelial cells could provide evidence for the role of oxidative injury in lung carcinogenesis, and help to address the potential public health implications of exposures to oxidant environments. PMID:25451016

A depleted ozone layer absorbs less UV-B, cooling the ozone layer, increasing the amount of UV-B observed to reach Earth, heating air by dissociating tropospheric and ground-level ozone, and heating oceans very efficiently by penetrating tens of meters into the mixed layer. UV-B is 48 times more energetic ("hotter") than IR absorbed by greenhouse gases

NASA Astrophysics Data System (ADS)

Ward, P. L.

2017-12-01

This new insight into the physics of radiation shows why changes in stratospheric ozone are observed to cause changes in global temperature. By 1970, manufactured CFC gases and ozone depletion began increasing. By 1993, increases in CFCs stopped as mandated by the Montreal Protocol. By 1995, increases in ozone depletion stopped. By 1998, increases in temperature stopped until 2014. Ozone is also depleted by halogen gases emitted from major basaltic lava flows, the largest of which, since 1783, occurred at Bardarbunga in Iceland in 2014, causing 2015 and 2016 to be the hottest years on record. Throughout Earth history, the largest basaltic lava flows were contemporaneous with periods of greatest warming and greatest levels of mass extinctions. Planck's empirical law shows that temperature of matter results from oscillation of all the bonds holding matter together. The higher the temperature, the higher the frequencies and amplitudes of oscillation. Thus, radiation from a nearby hotter body will make the absorbing body hotter than radiation from a cooler body. According to the Planck-Einstein relation, thermal energy (E) in matter and in radiation equals frequency of oscillation (ν) times the Planck constant (h), E=hν—the energy of a frictionless atomic oscillator. Since frequency is observed to be a very broad continuum extending from radio signals through visible light to gamma rays, thermal energy (E=hν) must also be a very broad continuum. Thermal flux cannot be represented properly by a single number of watts per square meter, as commonly assumed throughout the physical sciences, because all frequencies coexist and the number of watts increases with frequency. Thus, UV-B solar radiation is 48 times more energetic than IR terrestrial radiation absorbed by greenhouse gases and can make the absorbing body 48 times hotter. UV-B causes sunburn; no amount of IR can cause sunburn. Furthermore, in a basic experiment, I show that air containing more than 23 times normal concentrations of CO2, shows minimal warming compared to normal air when exposed to the same IR radiation. Dobson (1929) reported the close correlation between regions of high and low ozone concentrations and weather. Variation in ozone levels are closely associated with changes in the Multivariate ENSO Index and other atmospheric and oceanic oscillations.

High Concentrations of Ozone Air Pollution on Mount Everest: Health Implications for Sherpa Communities and Mountaineers.

PubMed

Semple, John L; Moore, G W Kent; Koutrakis, Petros; Wolfson, Jack M; Cristofanelli, Paolo; Bonasoni, Paolo

2016-12-01

Semple, John L., G.W. Kent Moore, Petros Koutrakis, Jack M. Wolfson, Paolo Cristofanelli, and Paolo Bonasoni. High concentrations of ozone air pollution on Mount Everest: health implications for Sherpa communities and mountaineers. High Alt Med Biol. 17:365-369, 2016.-Introduction: Populations in remote mountain regions are increasingly vulnerable to multiple climate mechanisms that influence levels of air pollution. Few studies have reported on climate-sensitive health outcomes unique to high altitude ecosystems. In this study, we report on the discovery of high-surface ozone concentrations and the potential impact on health outcomes on Mount Everest and the high Himalaya. Surface ozone measurements were collected during ascending transects in the Mount Everest region of Nepal with passive nitrite-coated Ogawa filter samplers to obtain 8-hour personal exposures (2860-5364 m asl). In addition, the Nepal Climate Observatory-Pyramid, a GAW-WMO Global Station sited in the Khumbu Valley (5079 m asl), collected ozone mixing ratios with photometric gas analyzer. Surface ozone measurements increased with altitude with concentrations that exceed 100 ppb (8-hour exposure). Highest values were during the spring season and the result of diverse contributions: hemispheric background values, the descent of ozone-rich stratospheric air, and the transport of tropospheric pollutants occurring at different spatial scales. Multiple climate factors, including descending stratospheric ozone and imported anthropogenic air masses from the Indo-Gangetic Plain, contribute to ambient ozone exposure levels in the vicinity of Mount Everest that are similar to if not higher than those reported in industrialized cities.

Foreign and Domestic Contributions to Springtime Ozone Pollution over China

NASA Astrophysics Data System (ADS)

Ni, R.; Lin, J.; Yan, Y.; Lin, W.; Chen, H.

2017-12-01

Ozone is a critical air pollutant that damages human health and vegetation. Previous studies for the United States and Europe have shown large influences of foreign emissions on domestic ozone levels, whereas the relative contributions of foreign versus domestic emissions are much less clear for China. Here, we use a global-regional two-way coupled model system based on GEOS-Chem to quantify the contributions to springtime ozone over China from anthropogenic emissions in major source regions across the globe. Our results indicate considerable influences of foreign anthropogenic pollution on China's ozone pollution. Together, foreign anthropogenic emissions enhance springtime surface ozone over China by 3 12 ppb. Of all ozone over China produced by global anthropogenic emissions, foreign emissions contribute 40% near the surface, and the contribution increases with altitude until a value of 80% in the upper troposphere. Impact from Japan and Korea is 1 2 ppb over east coastal regions, and negligible in inland. Anthropogenic emissions of South and South-East Asia increase ozone over Tibet and the Yunnan-Guizhou Plateau by up to 5 ppb, and their contribution increases with height due to strong vertical transport. Pollution from North America and Europe mainly accompanies strong westerly winds and frequent cyclonic activities that are favorable to long-range transport. European anthropogenic pollution enhances surface ozone by 1 3 ppb over West and North China. Despite a much longer transport distance, the contribution from North America is greater than European contribution due to the nearly doubled amount of anthropogenic NMVOC emissions. The high percentage contribution of foreign anthropogenic emissions to China's ozone pollution can be partly explained by excessive domestic NOx emissions that suppress ozone production efficiency and even destroy ozone. Our study is relevant to Chinese ozone pollution control and global environmental protection collaboration.

Effects of cadmium concentration on ozone-induced phytotoxicity in cress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Czuba, M.; Ormrod, D.P.

1974-01-01

Cadmium solutions at concentrations of 0, 10, 40, 100, 500 or 1000 ppm were applied to the soil around cress (Lepidium sativum L. cv. Fine Curled) every 4th day for several weeks. Four week old plants were fumigated once at ozone levels of 0, 5, 10, 20, 25 or 30-35 pphm for 6 hours. Plants that had received higher concentrations of cadmium showed markedly increased sensitivity to ozone in terms of visible leaf damage after ozone treatment. Plants receiving cadmium solution alone or those receiving ozone treatment alone either did not show leaf damage or as much leaf damage asmore » plants which had received both treatments. Mineral analyses of plant tissues showed the relationship between tissue content of both essential and toxic cations and the sensitivity of the plant to various ozone levels. Pigment analyses showed changes in chlorophyll amounts and ratios between treatments. Statistical analyses of data for morphological parameters showed that there is an interaction between Cd and ozone treatments over a range of concentrations.« less

The impacts of precursor reduction and meteorology on ground-level ozone in the Greater Toronto Area

NASA Astrophysics Data System (ADS)

Pugliese, S. C.; Murphy, J. G.; Geddes, J. A.; Wang, J. M.

2014-08-01

Tropospheric ozone (O3) is a major component of photochemical smog and is a known human health hazard, as well as a damaging factor for vegetation. Its precursor compounds, nitrogen oxides (NOx) and volatile organic compounds (VOCs), have a variety of anthropogenic and biogenic sources and exhibit non-linear effects on ozone production. As an update to previous studies on ground-level ozone in the Greater Toronto Area (GTA), we present an analysis of NO2, VOC and O3 data from federal and provincial governmental monitoring sites in the GTA from 2000 to 2012. We show that, over the study period, summertime 24 h VOC reactivity and NO2 midday (11:00-15:00) concentrations at all sites decreased significantly; since 2000, all sites experienced a decrease in NO2 of 28-62% and in measured VOC reactivity of at least 53-71%. Comparing 2002-2003 to 2011-2012, the summed reactivity of OH towards NO2 and a suite of measured VOCs decreased from 8.6 to 4.6 s-1. Ratios of reactive VOC pairs indicate that the effective OH concentration experienced by primary pollutants in the GTA has increased significantly over the study period. Despite the continuous decrease in precursor levels, ozone concentrations are not following the same pattern at all stations; it was found that the Canada-wide Standard for ozone continues to be exceeded at all monitoring stations. Additionally, while the years 2008-2011 had consistently lower ozone levels than previous years, 2012 experienced one of the highest recorded summertime ozone concentrations and a large number of smog episodes. We demonstrate that these high ozone observations in 2012 may be a result of the number of days with high solar radiation, the number of stagnant periods and the transport of high ozone levels from upwind regions.

The impacts of precursor reduction and meteorology on ground-level ozone in the Greater Toronto Area

NASA Astrophysics Data System (ADS)

Pugliese, S. C.; Murphy, J. G.; Geddes, J. A.; Wang, J. M.

2014-04-01

Tropospheric ozone (O3) is a major component of photochemical smog and is a known human health hazard as well as a damaging factor for vegetation. Its precursor compounds, nitrogen oxides (NOx) and volatile organic compounds (VOCs), have a variety of anthropogenic and biogenic sources and exhibit non-linear effects on ozone production. As an update to previous studies on ground-level ozone in the GTA, we present an analysis of NO2, VOC and O3 data from federal and provincial governmental monitoring sites in the GTA from 2000-2012. We show that over the study period, summertime 24 h VOC reactivity and NO2 midday (11:00-15:00) concentrations at all sites decreased significantly; since 2000, all sites experienced a decrease in NO2 of 28-62% and in measured VOC reactivity of at least 53-71%. Comparing 2002/2003 to 2011/2012, the summed reactivity of OH towards NO2 and a suite of measured VOCs decreased from 8.6 to 4.6 s-1. Ratios of reactive VOC pairs indicate that the effective OH concentration experienced by primary pollutants in the GTA has increased significantly over the study period. Despite the continuous decrease in precursor levels, ozone concentrations are not following the same pattern at all stations; it was found that the Canada-Wide Standard for ozone continues to be exceeded at all monitoring stations. Additionally, while the years 2008-2011 had consistently lower ozone levels than previous years, 2012 experienced one of the highest recorded summertime ozone concentrations and a large number of smog episodes. We demonstrate that these high ozone observations in 2012 may be a result of the number of days with high solar radiation, the number of stagnant periods and the transport of high ozone levels from upwind regions.

Effects of an ozone-generating air purifier on indoor secondary particles in three residential dwellings.

PubMed

Hubbard, H F; Coleman, B K; Sarwar, G; Corsi, R L

2005-12-01

The use of indoor ozone generators as air purifiers has steadily increased over the past decade. Many ozone generators are marketed to consumers for their ability to eliminate odors and microbial agents and to improve health. In addition to the harmful effects of ozone, recent studies have shown that heterogeneous and homogeneous reactions between ozone and some unsaturated hydrocarbons can be an important source of indoor secondary pollutants, including free radicals, carbonyls, carboxylic acids, and fine particles. Experiments were conducted in one apartment and two detached single-family dwellings in Austin, TX, to assess the effects of an ozone generator on indoor secondary organic aerosol concentrations in actual residential settings. Ozone was generated using a commercial ozone generator marketed as an air purifier, and particle measurements were recorded before, during, and after the release of terpenes from a pine oil-based cleaning product. Particle number concentration, ozone concentration, and air exchange rate were measured during each experiment. Particle number and mass concentrations increased when both terpenes and ozone were present at elevated levels. Experimental results indicate that ozone generators in the presence of terpene sources facilitate the growth of indoor fine particles in residential indoor atmospheres. Human exposure to secondary organic particles can be reduced by minimizing the intentional release of ozone, particularly in the presence of terpene sources. Past studies have shown that ozone-initiated indoor chemistry can lead to elevated concentrations of fine particulate matter, but have generally been completed in controlled laboratory environments and office buildings. We explored the effects of an explicit ozone generator marketed as an air purifier on the formation of secondary organic aerosol mass in actual residential indoor settings. Results indicate significant increases in number and mass concentrations for particles <0.7 microns in diameter, particularly when an ozone generator is used in the presence of a terpene source such as a pine oil-based cleaner. These results add evidence to the potentially harmful effects of ozone generation in residential environments.

An Analytical Investigation of Ozone Episodes in Bangu, Rio de Janeiro.

PubMed

Geraldino, Claudio Gabriel Pinheiro; Martins, Eduardo Monteiro; da Silva, Cleyton Martins; Arbilla, Graciela

2017-05-01

This study investigated the potential factors that contribute to frequent high levels of ozone as well as ozone episodes in Bangu, one of the most critical areas in the city of Rio de Janeiro regarding ozone levels. For 74 days in a two-year period (10.3%), the national air quality standard was exceeded. For the same period, a total of 378 days (51.8%) had ozone concentrations that were between 80 and 160 µg m -3 . A statistical analysis of pollutant concentrations and meteorological data as well as a kinetic and mechanistic analysis of VOC reactivity showed that the high ozone concentrations did not seem to be closely related to local emissions but, rather, were related to pollutant transport and triggered by photochemical activity. The mountains in the southern and northern part of the district contribute to the increase of surface temperatures and the accumulation of pollutants. The VOC/NO x ratios corresponded to a VOC-limited process.

Impact of Tropospheric Ozone on Summer Climate in China

NASA Astrophysics Data System (ADS)

Li, Shu; Wang, Tijian; Zanis, Prodromos; Melas, Dimitris; Zhuang, Bingliang

2018-04-01

The spatial distribution, radiative forcing, and climatic effects of tropospheric ozone in China during summer were investigated by using the regional climate model RegCM4. The results revealed that the tropospheric ozone column concentration was high in East China, Central China, North China, and the Sichuan basin during summer. The increase in tropospheric ozone levels since the industrialization era produced clear-sky shortwave and clear-sky longwave radiative forcing of 0.18 and 0.71 W m-2, respectively, which increased the average surface air temperature by 0.06 K and the average precipitation by 0.22 mm day-1 over eastern China during summer. In addition, tropospheric ozone increased the land-sea thermal contrast, leading to an enhancement of East Asian summer monsoon circulation over southern China and a weakening over northern China. The notable increase in surface air temperature in northwestern China, East China, and North China could be attributed to the absorption of longwave radiation by ozone, negative cloud amount anomaly, and corresponding positive shortwave radiation anomaly. There was a substantial increase in precipitation in the middle and lower reaches of the Yangtze River. It was related to the enhanced upward motion and the increased water vapor brought by strengthened southerly winds in the lower troposphere.

CMAQ predictions of tropospheric ozone in the U.S. southwest: influence of lateral boundary and synoptic conditions.

PubMed

Shi, Chune; Fernando, H J S; Hyde, Peter

2012-02-01

Phoenix, Arizona, has been an ozone nonattainment area for the past several years and it remains so. Mitigation strategies call for improved modeling methodologies as well as understanding of ozone formation and destruction mechanisms during seasons of high ozone events. To this end, the efficacy of lateral boundary conditions (LBCs) based on satellite measurements (adjusted-LBCs) was investigated, vis-à-vis the default-LBCs, for improving the predictions of Models-3/CMAQ photochemical air quality modeling system. The model evaluations were conducted using hourly ground-level ozone and NO(2) concentrations as well as tropospheric NO(2) columns and ozone concentrations in the middle to upper troposphere, with the 'design' periods being June and July of 2006. Both included high ozone episodes, but the June (pre-monsoon) period was characterized by local thermal circulation whereas the July (monsoon) period by synoptic influence. Overall, improved simulations were noted for adjusted-LBC runs for ozone concentrations both at the ground-level and in the middle to upper troposphere, based on EPA-recommended model performance metrics. The probability of detection (POD) of ozone exceedances (>75ppb, 8-h averages) for the entire domain increased from 20.8% for the default-LBC run to 33.7% for the adjusted-LBC run. A process analysis of modeling results revealed that ozone within PBL during bulk of the pre-monsoon season is contributed by local photochemistry and vertical advection, while the contributions of horizontal and vertical advections are comparable in the monsoon season. The process analysis with adjusted-LBC runs confirms the contributions of vertical advection to episodic high ozone days, and hence elucidates the importance of improving predictability of upper levels with improved LBCs. Copyright © 2011 Elsevier B.V. All rights reserved.

African Equatorial and Subtropical Ozone Plumes: Recurrences Timescales of the Brown Cloud Trans-African Plumes and Other Plumes

NASA Technical Reports Server (NTRS)

Chatfield, Robert B.; Thompson, Anne M.; Guan, Hong; Witte, Jacquelyn C.

2004-01-01

We have found repeated illustrations in the maps of Total Tropospheric Ozone (TTO) of apparent transport of ozone from the Indian Ocean to the Equatorial Atlantic Ocean. Most interesting are examples that coincide with the INDOEX observations of late northern winter, 1999. Three soundings associated with the SHADOZ (Southern Hemisphere Additional Ozonesondes) network help confirm and quantify degree of influence of pollution, lightning, and stratospheric sources, suggesting that perhaps 40% of increased Atlantic ozone could be Asian pollution during periods of maximum identified in the TTO maps. We outline recurrent periods of apparent ozone transport from Indian to Atlantic Ocean regions both during and outside the late-winter period. These are placed in the context of some general observations about factors controlling recurrence timescales for the expression of both equatorial and subtropical plumes. Low-level subtropical plumes are often controlled by frontal systems approaching the Namib coast; these direct mid-level air into either easterly equatorial plumes or westerly mid- troposphere plumes. Equatorial plumes of ozone cross Africa on an easterly path due to the occasional coincidence of two phenomena: (1) lofting of ozone to mid and upper levels, often in the Western Indian Ocean, and (2) the eastward extension of an Equatorial African easterly jet.

Forests and ozone: productivity, carbon storage, and feedbacks.

PubMed

Wang, Bin; Shugart, Herman H; Shuman, Jacquelyn K; Lerdau, Manuel T

2016-02-22

Tropospheric ozone is a serious air-pollutant, with large impacts on plant function. This study demonstrates that tropospheric ozone, although it damages plant metabolism, does not necessarily reduce ecosystem processes such as productivity or carbon sequestration because of diversity change and compensatory processes at the community scale ameliorate negative impacts at the individual level. This study assesses the impact of ozone on forest composition and ecosystem dynamics with an individual-based gap model that includes basic physiology as well as species-specific metabolic properties. Elevated tropospheric ozone leads to no reduction of forest productivity and carbon stock and to increased isoprene emissions, which result from enhanced dominance by isoprene-emitting species (which tolerate ozone stress better than non-emitters). This study suggests that tropospheric ozone may not diminish forest carbon sequestration capacity. This study also suggests that, because of the often positive relationship between isoprene emission and ozone formation, there is a positive feedback loop between forest communities and ozone, which further aggravates ozone pollution.

Ozone Depletion Caused by Rocket Engine Emissions: A Fundamental Limit on the Scale and Viability of Space-Based Geoengineering Schemes

NASA Astrophysics Data System (ADS)

Ross, M. N.; Toohey, D.

2008-12-01

Emissions from solid and liquid propellant rocket engines reduce global stratospheric ozone levels. Currently ~ one kiloton of payloads are launched into earth orbit annually by the global space industry. Stratospheric ozone depletion from present day launches is a small fraction of the ~ 4% globally averaged ozone loss caused by halogen gases. Thus rocket engine emissions are currently considered a minor, if poorly understood, contributor to ozone depletion. Proposed space-based geoengineering projects designed to mitigate climate change would require order of magnitude increases in the amount of material launched into earth orbit. The increased launches would result in comparable increases in the global ozone depletion caused by rocket emissions. We estimate global ozone loss caused by three space-based geoengineering proposals to mitigate climate change: (1) mirrors, (2) sunshade, and (3) space-based solar power (SSP). The SSP concept does not directly engineer climate, but is touted as a mitigation strategy in that SSP would reduce CO2 emissions. We show that launching the mirrors or sunshade would cause global ozone loss between 2% and 20%. Ozone loss associated with an economically viable SSP system would be at least 0.4% and possibly as large as 3%. It is not clear which, if any, of these levels of ozone loss would be acceptable under the Montreal Protocol. The large uncertainties are mainly caused by a lack of data or validated models regarding liquid propellant rocket engine emissions. Our results offer four main conclusions. (1) The viability of space-based geoengineering schemes could well be undermined by the relatively large ozone depletion that would be caused by the required rocket launches. (2) Analysis of space- based geoengineering schemes should include the difficult tradeoff between the gain of long-term (~ decades) climate control and the loss of short-term (~ years) deep ozone loss. (3) The trade can be properly evaluated only if our understanding of the stratospheric impact of rocket emissions is significantly improved. (4) Such an improved understanding requires a concerted effort of research including new in situ measurements in a variety of rocket plumes and a multi-scale modeling program similar in scope to the effort required to address the climate and ozone impacts of aircraft emissions.

Effect of tibolone pretreatment on kinases and phosphatases that regulate the expression and phosphorylation of Tau in the hippocampus of rats exposed to ozone.

PubMed

Pinto-Almazan, Rodolfo; Segura-Uribe, Julia J; Soriano-Ursúa, Marvin A; Farfán-García, Eunice D; Gallardo, Juan M; Guerra-Araiza, Christian

2018-03-01

Oxidative stress (OS) is a key process in the development of many neurodegenerative diseases, memory disorders, and other pathological processes related to aging. Tibolone (TIB), a synthetic hormone used as a treatment for menopausal symptoms, decreases lipoperoxidation levels, prevents memory impairment and learning disability caused by ozone (O 3 ) exposure. However, it is not clear if TIB could prevent the increase in phosphorylation induced by oxidative stress of the microtubule-associated protein Tau. In this study, the effects of TIB at different times of administration on the phosphorylation of Tau, the activation of glycogen synthase kinase-3β (GSK3β), and the inactivation of Akt and phosphatases PP2A and PTEN induced by O 3 exposure were assessed in adult male Wistar rats. Rats were divided into 10 groups: control group (ozone-free air plus vehicle [C]), control + TIB group (ozone-free air plus TIB 1 mg/kg [C + TIB]); 7, 15, 30, and 60 days of ozone exposure groups [O 3 ] and 7, 15, 30, and 60 days of TIB 1 mg/kg before ozone exposure groups [O 3 + TIB]. The effects of O 3 exposure and TIB administration were assessed by western blot analysis of total and phosphorylated Tau, GSK3β, Akt, PP2A, and PTEN proteins and oxidative stress marker nitrotyrosine, and superoxide dismutase activity and lipid peroxidation of malondialdehyde by two different spectrophotometric methods (Marklund and TBARS, respectively). We observed that O 3 exposure increases Tau phosphorylation, which is correlated with decreased PP2A and PTEN protein levels, diminished Akt protein levels, and increased GSK3β protein levels in the hippocampus of adult male rats. The effects of O 3 exposure were prevented by the long-term treatment (over 15 days) with TIB. Malondialdehyde and nitrotyrosine levels increased from 15 to 60 days of exposure to O 3 in comparison to C group, and superoxide dismutase activity decreased. Furthermore, TIB administration limited the changes induced by O 3 exposure. Our results suggest a beneficial use of hormone replacement therapy with TIB to prevent neurodegeneration caused by O 3 exposure in rats.

Medical ozone promotes Nrf2 phosphorylation reducing oxidative stress and pro-inflammatory cytokines in multiple sclerosis patients.

PubMed

Delgado-Roche, Livan; Riera-Romo, Mario; Mesta, Fernando; Hernández-Matos, Yanet; Barrios, Juan M; Martínez-Sánchez, Gregorio; Al-Dalaien, Said M

2017-09-15

Oxidative stress and inflammation play key roles in the pathogenesis of Multiple sclerosis (MS). Different drugs have been used in the clinical practice, however, there is not a completely effective treatment. Due to its potential therapeutic action, medical ozone represents a promising approach for neurodegenerative disorders. The aim of the present study was to address the role of ozone therapy on the cellular redox state in MS patients. Ozone (20μg/ml) was administered three times per week during a month by rectal insufflation. The effect of ozone therapy on biomarkers of oxidative stress and inflammation was addressed by spectrophotometric and immunoenzymatic assays. Furthermore, we investigated the action of ozone on CK2 expression and Nrf2 phosphorylation by western blotting analysis. Medical ozone significantly improved (P < 0.05) the activity of antioxidant enzymes and increased the levels of cellular reduced glutathione. In accordance, a significant reduction (P < 0.05) of oxidative damage on lipids and proteins was observed in ozone-treated patients. As well, the levels of pro-inflammatory cytokines TNFα and IL-1β were lower after ozone treatment. Ozone therapy incremented the CK2 expression together with Nrf2 phosphorylation in mononuclear cells of MS patients. These findings suggest that ozone´s antioxidant and anti-inflammatory effects might be partially associated with an induction of Nrf2 phosphorylation and activation. These results provide new insights on the molecular events modulated by ozone, and pointed out ozone therapy as a potential therapeutic alternative for MS patients. Copyright © 2017. Published by Elsevier B.V.

A Comparative Study on Ozone Photochemical Formation in the Megacities of Tianjin and Shanghai, China

NASA Astrophysics Data System (ADS)

Ran, L.; Zhao, C.; Xu, W.; Geng, F.; Lu, X.; Han, M.; Lin, W.; Xu, X.

2011-12-01

As one of the most widespread and stubborn environmental issues, the ozone problem has been of particular concern for many years, given the potential adverse effects of high ozone concentrations on public health and agricultural productivity. In the past decades, rapid urbanization and industrialization have given rise to a significant increase in ozone precursor emissions in many regions of China, especially in the densely populated megacities. Due to the highly nonlinear impacts of ozone precursors including nitrogen oxides (NOx) and various volatile organic compounds (VOCs) on ozone photochemistry, formation of ozone affected by different precursor emission patterns in those megacities has exhibited different characteristics. A comparative analysis of ozone photochemical production in the megacities of Tianjin and Shanghai has thus been carried out, using the data sets of surface ozone and its precursors measured respectively at an urban and a suburban site of the two megacities during the summertime. Observation-based analysis indicated an elevated ozone daily peak under photochemistry dominant conditions from the urban center to the suburb in both regions, nevertheless bearing different reasons. Ozone production was generally sensitive to VOCs in the Tianjin region, leading to a relatively higher level of ozone in the suburb where reactive VOCs were abundantly released from a number of industrial facilities, whereas a sensitivity of ozone production to NOx was found in Shanghai. The high level of NOx emitted mainly by motor vehicles in urban Shanghai largely inhibited ozone formation and resulted in a much more rapid decrease in ozone concentrations after reaching the daily maximum around midday compared with the other three areas. Ozone pollution in the megacity of Tianjin was more representative of the regional condition, implying that combined efforts would be needed to bring the ozone problem under control within this region. Improved understanding of ozone formation in the two megacities would be quite imperative and critical to provide a solid scientific basis for designing effective ozone control strategies.

Peri-implantation Ozone Exposure Alters Uterine Artery Flow and Induces Fetal Growth Restriction in Rats

EPA Science Inventory

Epidemiological studies suggest a relationship between air pollutant exposures to various adverse pregnancy outcomes. Elevated ambient ozone levels during the first and second trimesters have demonstrated an increased correlation to preeclampsia, gestational diabetes, and intraut...

Short-term effects of multiple ozone metrics on daily mortality in a megacity of China.

PubMed

Li, Tiantian; Yan, Meilin; Ma, Wenjun; Ban, Jie; Liu, Tao; Lin, Hualiang; Liu, Zhaorong

2015-06-01

Epidemiological studies have widely demonstrated association between ambient ozone and mortality, though controversy remains, and most of them only use a certain metric to assess ozone levels. However, in China, few studies have investigated the acute effects of ambient ozone, and rare studies have compared health effects of multiple daily metrics of ozone. The present analysis aimed to explore variability of estimated health effects by using multiple temporal ozone metrics. Six metrics of ozone, 1-h maximum, maximum 8-h average, 24-h average, daytime average, nighttime average, and commute average, were used in a time-series study to investigate acute mortality associated with ambient ozone pollution in Guangzhou, China, using 3 years of daily data (2006-2008). We used generalized linear models with Poisson regression incorporating natural spline functions to analyze the mortality, ozone, and covariate data. We also examined the association by season. Daily 1- and 8-h maximum, 24-h average, and daytime average concentrations yielded statistically significant associations with mortality. An interquartile range (IQR) of O3 metric increase of each ozone metric (lag 2) corresponds to 2.92 % (95 % confidence interval (CI) 0.24 to 5.66), 3.60 % (95 % CI, 0.92 to 8.49), 3.03 % (95 % CI, 0.57 to 15.8), and 3.31 % (95 % CI, 0.69 to 10.4) increase in daily non-accidental mortality, respectively. Nighttime and commute metrics were weakly associated with increased mortality rate. The associations between ozone and mortality appeared to be more evident during cool season than in the warm season. Results were robust to adjustment for co-pollutants, weather, and time trend. In conclusion, these results indicated that ozone, as a widespread pollutant, adversely affects mortality in Guangzhou.

Changes in biologically active ultraviolet radiation reaching the Earth's surface.

PubMed

Madronich, S; McKenzie, R L; Björn, L O; Caldwell, M M

1998-10-01

Stratospheric ozone levels are near their lowest point since measurements began, so current ultraviolet-B (UV-B) radiation levels are thought to be close to their maximum. Total stratospheric content of ozone-depleting substances is expected to reach a maximum before the year 2000. All other things being equal, the current ozone losses and related UV-B increases should be close to their maximum. Increases in surface erythemal (sunburning) UV radiation relative to the values in the 1970s are estimated to be: about 7% at Northern Hemisphere mid-latitudes in winter/spring; about 4% at Northern Hemisphere mid-latitudes in summer/fall; about 6% at Southern Hemisphere mid-latitudes on a year-round basis; about 130% in the Antarctic in spring; and about 22% in the Arctic in spring. Reductions in atmospheric ozone are expected to result in higher amounts of UV-B radiation reaching the Earth's surface. The expected correlation between increases in surface UV-B radiation and decreases in overhead ozone has been further demonstrated and quantified by ground-based instruments under a wide range of conditions. Improved measurements of UV-B radiation are now providing better geographical and temporal coverage. Surface UV-B radiation levels are highly variable because of cloud cover, and also because of local effects including pollutants and surface reflections. These factors usually decrease atmospheric transmission and therefore the surface irradiances at UV-B as well as other wavelengths. Occasional cloud-induced increases have also been reported. With a few exceptions, the direct detection of UV-B trends at low- and mid-latitudes remains problematic due to this high natural variability, the relatively small ozone changes, and the practical difficulties of maintaining long-term stability in networks of UV-measuring instruments. Few reliable UV-B radiation measurements are available from pre-ozone-depletion days. Satellite-based observations of atmospheric ozone and clouds are being used, together with models of atmospheric transmission, to provide global coverage and long-term estimates of surface UV-B radiation. Estimates of long-term (1979-1992) trends in zonally averaged UV irradiances that include cloud effects are nearly identical to those for clear-sky estimates, providing evidence that clouds have not influenced the UV-B trends. However, the limitations of satellite-derived UV estimates should be recognized. To assess uncertainties inherent in this approach, additional validations involving comparisons with ground-based observations are required. Direct comparisons of ground-based UV-B radiation measurements between a few mid-latitude sites in the Northern and Southern Hemispheres have shown larger differences than those estimated using satellite data. Ground-based measurements show that summertime erythemal UV irradiances in the Southern Hemisphere exceed those at comparable latitudes of the Northern Hemisphere by up to 40%, whereas corresponding satellite-based estimates yield only 10-15% differences. Atmospheric pollution may be a factor in this discrepancy between ground-based measurements and satellite-derived estimates. UV-B measurements at more sites are required to determine whether the larger observed differences are globally representative. High levels of UV-B radiation continue to be observed in Antarctica during the recurrent spring-time ozone hole. For example, during ozone-hole episodes, measured biologically damaging radiation at Palmer Station, Antarctica (64 degrees S) has been found to approach and occasionally even exceed maximum summer values at San Diego, CA, USA (32 degrees N). Long-term predictions of future UV-B levels are difficult and uncertain. Nevertheless, current best estimates suggest that a slow recovery to pre-ozone depletion levels may be expected during the next half-century. (ABSTRACT TRUNCATED)

Optimal Extraction of Tropospheric Ozone Column by Simultaneous Use of OMI and TES Data and the Surface Temperature

NASA Astrophysics Data System (ADS)

Mobasheri, M. R.; Shirazi, H.

2015-12-01

This article aims to increase the accuracy of Ozone data from tropospheric column (TOC) of the OMI and TES satellite instruments. To validate the estimated amount of satellite data, Ozonesonde data is used. The vertical resolution in both instruments in the tropospheric atmosphere decreases so that the degree of freedom signals (DOFS) on the average for TES is reduced to 2 and for OMI is reduced to1. But this decline in accuracy in estimation of tropospheric ozone is more obvious in urban areas so that estimated ozone in both instruments alone in non-urban areas show a high correlation with Ozonesonde. But in urban areas this correlation is significantly reduced, due to the ozone pre-structures and consequently an increase on surface-level ozone in urban areas. In order to improve the accuracy of satellite data, the average tropospheric ozone data from the two instruments were used. The aim is to increase the vertical resolution of ozone profile and the results clearly indicate an increase in correlations, but nevertheless the satellite data have a positive bias towards the earth data. To reduce the bias, with the solar flux and nitrogen dioxide values and surface temperatures are calculated as factors of ozone production on the earth's surface and formation of mathematical equations based on coefficients for each of the mentioned values and multiplication of these coefficients by satellite data and repeated comparison with the values of Ozonesonde, the results showed that bias in urban areas is greatly reduced.

What would have happened to the ozone layer if chlorofluorocarbons (CFCs) had not been regulated?

NASA Astrophysics Data System (ADS)

Newman, P. A.; Oman, L. D.; Douglass, A. R.; Fleming, E. L.; Frith, S. M.; Hurwitz, M. M.; Kawa, S. R.; Jackman, C. H.; Krotkov, N. A.; Nash, E. R.; Nielsen, J. E.; Pawson, S.; Stolarski, R. S.; Velders, G. J.

2008-12-01

Ozone depletion by chlorofluorocarbons (CFCs) was first proposed by Molina and Rowland in their 1974 Nature paper. Since that time, the scientific connection between ozone losses and CFCs and other ozone depleting substances (ODSs) has been firmly established with laboratory measurements, atmospheric observations, and modeling research. The nations of the world implemented the Montreal Protocol (and amendments) which stopped ODS production in 1992. In this presentation we use a fully coupled radiation- chemical-dynamical model to simulate a future world where ODSs were never regulated and ODS production grew at an annual rate of 3%. In this "world avoided" simulation, 17% of the globally average column ozone is destroyed by 2020, and 67% is destroyed by 2065 in comparison to 1980. Large ozone depletions in the polar region become year-round rather than just seasonal as is currently observed in the Antarctic ozone hole. Very large temperature decreases are observed in response to circulation changes and decreased shortwave radiation absorption by ozone. Ozone levels in the tropical lower stratosphere remain constant until about 2053 and then collapse to near zero by 2058 as a result of heterogeneous chemical processes (as currently observed in the Antarctic ozone hole). The tropical cooling that triggers the ozone collapse is caused by an increase of the tropical upwelling. In response to ozone changes, ultraviolet (UV) radiation increases, tripling the erythemal (sunburn) radiation in the northern summer mid-latitudes by 2065.

Principal Component Analysis of Chlorophyll Content in Tobacco, Bean and Petunia Plants Exposed to Different Tropospheric Ozone Concentrations

NASA Astrophysics Data System (ADS)

Borowiak, Klaudia; Zbierska, Janina; Budka, Anna; Kayzer, Dariusz

2014-06-01

Three plant species were assessed in this study - ozone-sensitive and -resistant tobacco, ozone-sensitive petunia and bean. Plants were exposed to ambient air conditions for several weeks in two sites differing in tropospheric ozone concentrations in the growing season of 2009. Every week chlorophyll contents were analysed. Cumulative ozone effects on the chlorophyll content in relation to other meteorological parameters were evaluated using principal component analysis, while the relation between certain days of measurements of the plants were analysed using multivariate analysis of variance. Results revealed variability between plant species response. However, some similarities were noted. Positive relations of all chlorophyll forms to cumulative ozone concentration (AOT 40) were found for all the plant species that were examined. The chlorophyll b/a ratio revealed an opposite position to ozone concentration only in the ozone-resistant tobacco cultivar. In all the plant species the highest average chlorophyll content was noted after the 7th day of the experiment. Afterwards, the plants usually revealed various responses. Ozone-sensitive tobacco revealed decrease of chlorophyll content, and after few weeks of decline again an increase was observed. Probably, due to the accommodation for the stress factor. While during first three weeks relatively high levels of chlorophyll contents were noted in ozone-resistant tobacco. Petunia revealed a slow decrease of chlorophyll content and the lowest values at the end of the experiment. A comparison between the plant species revealed the highest level of chlorophyll contents in ozone-resistant tobacco.

High levels of ultraviolet radiation observed by ground-based instruments below the 2011 Arctic ozone hole

NASA Astrophysics Data System (ADS)

Bernhard, G.; Dahlback, A.; Fioletov, V.; Heikkilä, A.; Johnsen, B.; Koskela, T.; Lakkala, K.; Svendby, T.

2013-11-01

Greatly increased levels of ultraviolet (UV) radiation were observed at thirteen Arctic and sub-Arctic ground stations in the spring of 2011, when the ozone abundance in the Arctic stratosphere dropped to the lowest amounts on record. Measurements of the noontime UV Index (UVI) during the low-ozone episode exceeded the climatological mean by up to 77% at locations in the western Arctic (Alaska, Canada, Greenland) and by up to 161% in Scandinavia. The UVI measured at the end of March at the Scandinavian sites was comparable to that typically observed 15-60 days later in the year when solar elevations are much higher. The cumulative UV dose measured during the period of the ozone anomaly exceeded the climatological mean by more than two standard deviations at 11 sites. Enhancements beyond three standard deviations were observed at seven sites and increases beyond four standard deviations at two sites. At the western sites, the episode occurred in March, when the Sun was still low in the sky, limiting absolute UVI anomalies to less than 0.5 UVI units. At the Scandinavian sites, absolute UVI anomalies ranged between 1.0 and 2.2 UVI units. For example, at Finse, Norway, the noontime UVI on 30 March was 4.7, while the climatological UVI is 2.5. Although a UVI of 4.7 is still considered moderate, UV levels of this amount can lead to sunburn and photokeratitis during outdoor activity when radiation is reflected upward by snow towards the face of a person or animal. At the western sites, UV anomalies can be well explained with ozone anomalies of up to 41% below the climatological mean. At the Scandinavian sites, low ozone can only explain a UVI increase of 50-60%. The remaining enhancement was mainly caused by the absence of clouds during the low-ozone period.

High levels of ultraviolet radiation observed by ground-based instruments below the 2011 Arctic ozone hole

NASA Astrophysics Data System (ADS)

Bernhard, G.; Dahlback, A.; Fioletov, V.; Heikkilä, A.; Johnsen, B.; Koskela, T.; Lakkala, K.; Svendby, T. M.

2013-06-01

Greatly increased levels of ultraviolet (UV) radiation were observed at thirteen Arctic and sub-Arctic ground stations in the spring of 2011 when the ozone abundance in the Arctic stratosphere dropped to the lowest amounts on record. Measurements of the noontime UV Index (UVI) during the low-ozone episode exceeded the climatological mean by up to 77% at locations in the western Arctic (Alaska, Canada, Greenland) and by up to 161% in Scandinavia. The UVI measured at the end of March at the Scandinavian sites was comparable to that typically observed 15-60 days later in the year when solar elevations are much higher. The cumulative UV dose measured during the period of the ozone anomaly exceeded the climatological mean by more than two standard deviations at 11 sites. Enhancements beyond three standard deviations were observed at seven sites and increases beyond four standard deviations at two sites. At the western sites, the episode occurred in March when the Sun was still low in the sky, limiting absolute UVI anomalies to less than 0.5 UVI units. At the Scandinavian sites, absolute UVI anomalies ranged between 1.0 and 2.2 UVI units. For example, at Finse, Norway, the noontime UVI on 30 March was 4.7 while the climatological UVI is 2.5. Although a UVI of 4.7 is still considered moderate, UV levels of this amount can lead to sunburn and photokeratitis during outdoor activity when radiation is reflected upward by snow towards the face of a person or animal. At the western sites, UV anomalies can be well explained with ozone anomalies of up to 41% below the climatological mean. At the Scandinavian sites, low ozone can only explain a UVI increase by 50-60%. The remaining enhancement was mainly caused by the absence of clouds during the low-ozone period.

Has the sensitivity of soybean cultivars to ozone pollution increased with time? An analysis of published dose-response data

USDA-ARS?s Scientific Manuscript database

The rising trend in concentrations of ground-level ozone (O3) – a common air pollutant and phytotoxin – currently being experienced in some world regions represents a threat to agricultural yield. Soybean (Glycine max (L.) Merr.) is an O3-sensitive crop species, and is experiencing increasing globa...

[The relationship between the ozone layer and skin cancer].

PubMed

Sánchez C, Francisca

2006-09-01

In the recent decades, a sustained increase in the worldwide incidence of skin cancer has been observed and Chile is not the exception. The most important risk factor is the exaggerated and repeated exposure to ultraviolet radiation coming from the sun. The ozone layer restricts the transmission of type B and C ultraviolet light. Since 1980, a sustained depletion of stratospheric ozone levels is occurring, specially in middle latitudes (-30 to -60). Along with this depletion, the amount of ultraviolet light that reaches the earth surface is increasing. This article reviews some basic concepts about the ozone layer and the association between its depletion and skin cancer. The general population should be informed about the risks of inadequate and exaggerated exposure to sunlight.

Ozone Differentially Affects Perception of Plant Volatiles in Western Honey Bees.

PubMed

Dötterl, Stefan; Vater, Marina; Rupp, Thomas; Held, Andreas

2016-06-01

Floral scents play a key role in mediating plant-pollinator interactions. Volatile organic compounds (VOCs) emitted by flowers are used by flower visitors as olfactory cues to locate flowers, both from a distance and at close range. More recently it has been demonstrated that reactive molecules such as ozone can modify or degrade VOCs, and this may impair the communication between plants and their pollinators. However, it is not known whether such reactive molecules also may affect the olfactory system of pollinators, and thus not only influence signal transmission but perception of the signal. In this study, we used electroantennographic measurements to determine the effect of increased levels of ozone on antennal responses in western honey bees (Apis mellifera L.). Linalool and 2-phenylethanol, both known to be involved in location of flowers by the bees, and (Z)-3-hexenyl acetate, a widespread green leaf volatile also detected by bees, were used. The results showed that ozone affected antennal responses to the different substances differently. Ozone decreased antennal responses to (Z)-3-hexenyl acetate, whereas responses to linalool and 2-phenylethanol were not influenced by ozone. Overall, the study does not provide evidence that pollination by honey bees is impaired by damage in the olfactory system of the bees caused by increased levels of ozone, at least when linalool and 2-phenylethanol are the attractive signals. However, the results also suggest that ozone can change the overall perception of an odor blend. This might have negative effects in pollination systems and other organismic interactions mediated by specific ratios of compounds.

Observations of Europe wide Trends in background and peak O3, CO and NO2 levels

NASA Astrophysics Data System (ADS)

Fleming, Z. L.; Monks, P. S.; Brunsdon, C.; Henne, S.; Buchmann, B.; Konovalov, I.; Beekman, M.

2009-04-01

The GEOMON (Global Earth Observation and MONitoring) project has produced a harmonised data set of trace gases from various ground-based measurement stations. These stations belong to a variety of regional, national and European air quality networks (e.g. EMEP, GAW). Investigations into instrumental calibration and data quality have been carried out in order to make comparison between the sites as accurate as possible for a long time-scale trend analysis. Ozone seasonal cycles at the various sites have been compared, showing characteristic cycles according to latitude, elevation, vicinity to coastal areas and pollution sources and population nearby. A de-trending of this seasonal cycle revealed long-term variations in ozone and a considerable difference between background and peak ozone trends between sites. National, European and international legislation has aimed at reducing CO and NO2 and correspondingly, reduce O3 levels over the last 20 years but the trends are not as clear cut and reveal that there is not a homogeneous reduction in these species across Europe. Splitting the data into seasonal periods and also into lower and upper concentration percentiles shows us more clearly how the species vary across Europe. There is a tendency for peak ozone levels to decrease, whilst the background levels have mostly increased. Averages, lower and upper percentiles of these species at the GEOMON stations are shown on European maps and the distribution of annual ozone trends is evaluated. Comparisons with models that estimate the lower and upper percentiles of ozone during summer overestimate ozone levels but not uniformly across Europe.

Ground-level ozone pollution and its health impacts in China

NASA Astrophysics Data System (ADS)

Liu, Huan; Liu, Shuai; Xue, Boru; Lv, Zhaofeng; Meng, Zhihang; Yang, Xiaofan; Xue, Tao; Yu, Qiao; He, Kebin

2018-01-01

In recent years, ground-level ozone pollution in China has become an increasingly prominent problem. This study simulated and analyzed spatiotemporal distribution of ozone and exposure level by the Weather Research and Forecasting (WRF)-Community Multiscale Air Quality (CMAQ) models and monitoring data from 1516 national air quality monitoring stations in China during 2015. The simulation results show that the Sichuan Basin, Shandong, Shanxi, Henan, Anhui, Qinghai-Tibetan Plateau, Yangtze River Delta (YRD), Pearl River Delta (PRD) and Beijing-Tianjin-Hebei (BTH) region had relatively high average annual concentrations of ozone. The regions with more than 10% nonattainment days of 160 μg/m3 (daily maximum 8-h) are mainly concentrated in BTH, Shandong Peninsula and YRD, where large seasonal variations were also found. Exposure levels were calculated based on population data and simulated ozone concentrations. The cumulative population exposed to daily maximum 8-h concentration greater than or equal to 100 μg/m3 was 816.04 million, 61.17% of the total. Three methods were used to estimate the mortality of chronic obstructive pulmonary disease (COPD) attributable to ozone. A comparative study using different exposure concentrations and threshold concentrations found large variations among these methods, although they were all peer-reviewed methods. The estimated mortality of COPD caused by ozone in China in 2015 ranged from 55341 to 80280, which mainly distributed in Beijing, Shandong, Henan, Hubei and Sichuan Province, the YRD and PRD region.

Photochemical model evaluation of the ground-level ozone impacts on ambient air quality and vegetation health in the Alberta oil sands region: Using present and future emission scenarios

NASA Astrophysics Data System (ADS)

Vijayaraghavan, Krish; Cho, Sunny; Morris, Ralph; Spink, David; Jung, Jaegun; Pauls, Ron; Duffett, Katherine

2016-09-01

One of the potential environmental issues associated with oil sands development is increased ozone formation resulting from NOX and volatile organic compound emissions from bitumen extraction, processing and upgrading. To manage this issue in the Athabasca Oil Sands Region (AOSR) in northeast Alberta, a regional multi-stakeholder group, the Cumulative Environmental Management Association (CEMA), developed an Ozone Management Framework that includes a modelling based assessment component. In this paper, we describe how the Community Multi-scale Air Quality (CMAQ) model was applied to assess potential ground-level ozone formation and impacts on ambient air quality and vegetation health for three different ozone precursor cases in the AOSR. Statistical analysis methods were applied, and the CMAQ performance results met the U.S. EPA model performance goal at all sites. The modelled 4th highest daily maximum 8-h average ozone concentrations in the base and two future year scenarios did not exceed the Canada-wide standard of 65 ppb or the newer Canadian Ambient Air Quality Standards of 63 ppb in 2015 and 62 ppb in 2020. Modelled maximum 1-h ozone concentrations in the study were well below the Alberta Ambient Air Quality Objective of 82 ppb in all three cases. Several ozone vegetation exposure metrics were also evaluated to investigate the potential impact of ground-level ozone on vegetation. The chronic 3-months SUM60 exposure metric is within the CEMA baseline range (0-2000 ppb-hr) everywhere in the AOSR. The AOT40 ozone exposure metric predicted by CMAQ did not exceed the United Nations Economic Commission for Europe (UN/ECE) threshold of concern of 3000 ppb-hr in any of the cases but is just below the threshold in high-end future emissions scenario. In all three emission scenarios, the CMAQ predicted W126 ozone exposure metric is within the CEMA baseline threshold of 4000 ppb-hr. This study outlines the use of photochemical modelling of the impact of an industry (oil sands) on ground-level ozone levels as an air quality management tool in the AOSR. It allows an evaluation of the relationships between the pollutants emitted to the atmosphere and potential ground level ozone concentrations throughout the AOSR thereby extending the spatial coverage of the results beyond the monitoring network and also allowing an assessment of the potential impacts of possible future emission cases.

Impact of climate change on ozone-related mortality and morbidity in Europe.

PubMed

Orru, Hans; Andersson, Camilla; Ebi, Kristie L; Langner, Joakim; Aström, Christofer; Forsberg, Bertil

2013-02-01

Ozone is a highly oxidative pollutant formed from precursors in the presence of sunlight, associated with respiratory morbidity and mortality. All else being equal, concentrations of ground-level ozone are expected to increase due to climate change. Ozone-related health impacts under a changing climate are projected using emission scenarios, models and epidemiological data. European ozone concentrations are modelled with the model of atmospheric transport and chemistry (MATCH)-RCA3 (50×50 km). Projections from two climate models, ECHAM4 and HadCM3, are applied under greenhouse gas emission scenarios A2 and A1B, respectively. We applied a European-wide exposure-response function to gridded population data and country-specific baseline mortality and morbidity. Comparing the current situation (1990-2009) with the baseline period (1961-1990), the largest increase in ozone-associated mortality and morbidity due to climate change (4-5%) have occurred in Belgium, Ireland, the Netherlands and the UK. Comparing the baseline period and the future periods (2021-2050 and 2041-2060), much larger increases in ozone-related mortality and morbidity are projected for Belgium, France, Spain and Portugal, with the impact being stronger using the climate projection from ECHAM4 (A2). However, in Nordic and Baltic countries the same magnitude of decrease is projected. The current study suggests that projected effects of climate change on ozone concentrations could differentially influence mortality and morbidity across Europe.

Quantifying wintertime boundary layer ozone production from frequent profile measurements in the Uinta Basin, UT, oil and gas region

NASA Astrophysics Data System (ADS)

Schnell, Russell C.; Johnson, Bryan J.; Oltmans, Samuel J.; Cullis, Patrick; Sterling, Chance; Hall, Emrys; Jordan, Allen; Helmig, Detlev; Petron, Gabrielle; Ahmadov, Ravan; Wendell, James; Albee, Robert; Boylan, Patrick; Thompson, Chelsea R.; Evans, Jason; Hueber, Jacques; Curtis, Abigale J.; Park, Jeong-Hoo

2016-09-01

As part of the Uinta Basin Winter Ozone Study, January-February 2013, we conducted 937 tethered balloon-borne ozone vertical and temperature profiles from three sites in the Uinta Basin, Utah (UB). Emissions from oil and gas operations combined with snow cover were favorable for producing high ozone-mixing ratios in the surface layer during stagnant and cold-pool episodes. The highly resolved profiles documented the development of approximately week-long ozone production episodes building from regional backgrounds of 40 ppbv to >165 ppbv within a shallow cold pool up to 200 m in depth. Beginning in midmorning, ozone-mixing ratios increased uniformly through the cold pool layer at rates of 5-12 ppbv/h. During ozone events, there was a strong diurnal cycle with each succeeding day accumulating 4-8 ppbv greater than the previous day. The top of the elevated ozone production layer was nearly uniform in altitude across the UB independent of topography. Above the ozone production layer, mixing ratios decreased with height to 400 m above ground level where they approached regional background levels. Rapid clean-out of ozone-rich air occurred within a day when frontal systems brought in fresh air. Solar heating and basin topography led to a diurnal flow pattern in which daytime upslope winds distributed ozone precursors and ozone in the Basin. NOx-rich plumes from a coal-fired power plant in the eastern sector of the Basin did not appear to mix down into the cold pool during this field study.

Changes in PEP carboxylase, rubisco and rubisco activase mRNA levels from maize (Zea mays) exposed to a chronic ozone stress.

PubMed

Leitao, Louis; Maoret, Jean-José; Biolley, Jean-Philippe

2007-01-01

We quantified the ozone impact on levels of Zea mays L. cv. Chambord mRNAs encoding C4-phosphoenolpyruvate carboxylase (C4-PEPc), ribulose-l,5-bisphosphate carboxylase/oxygenase small and large subunits (Rubisco-SSU and Rubisco-LSU, respectively) and Rubisco activase (RCA) using real-time RT-PCR. Foliar pigment content, PEPc and Rubisco protein amounts were simultaneously determined. Two experiments were performed to study the ozone response of the 5th and the 10th leaf. For each experiment, three ozone concentrations were tested in open-top chambers: non-filtered air (NF, control) and non-filtered air containing 40 (+40) and 80 nL L-1 (+80) ozone. Regarding the 5th leaf, +40 atmosphere induced a loss in pigmentation, PEPc and Rubisco activase mRNAs. However, it was unable to notably depress carboxylase protein amounts and mRNAs encoding Rubisco. Except for Rubisco mRNAs, all other measured parameters from 5th leaf were depressed by +80 atmosphere. Regarding the 10th leaf, +40 atmosphere increased photosynthetic pigments and transcripts encoding Rubisco and Rubisco activase. Rubisco and PEPc protein amounts were not drastically changed, even if they tended to be increased. Level of C4-PEPc mRNA remained almost stable. In response to +80 atmosphere, pigments and transcripts encoding PEPc were notably decreased. Rubisco and PEPc protein amounts also declined to a lesser extent. Conversely, the level of transcripts encoding both Rubisco subunits and Rubisco activase that were not consistently disturbed tended to be slightly augmented. So, the present study suggests that maize leaves can respond differentially to a similar ozone stress.

Investigation of Ground-Level Ozone and High-Pollution Episodes in a Megacity of Eastern China

PubMed Central

Zhao, Heng; Wang, Shanshan; Wang, Wenxin; Liu, Rui; Zhou, Bin

2015-01-01

Differential Optical Absorption Spectroscopy (DOAS) was used for the long-term observation of ground-level ozone (O3) from March 2010 to March 2013 over Shanghai, China. The 1-hour average concentration of O3 was 27.2 ± 17.0 ppbv. O3 level increased during spring, reached the peak in late spring and early summer, and then decreased in autumn and finally dropped to the bottom in winter. The highest monthly average O3 concentration in June (41.1 ppbv) was nearly three times as high as the lowest level recorded in December (15.2 ppbv). In terms of pollution episodes, 56 hourly samples (on 14 separate days) in 2010 exceeded the 1-hour ozone limit of 200 μg/m3 specified by the Grade II of the Chinese Ambient Air Quality Standards (CAAQS, revised GB 3095-2012). Utilizing the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model, the primary contribution to high ozone days (HODs) was identified as the regional transportation of volatile organic compounds (VOC) and high concentrations of O3 from the chemical industrial zone in the Jinshan district of Shanghai. HODs showed higher concentrations of HONO and NO2 than non-episode conditions, implying that HONO at high concentration during HODs was capable of increasing the O3 concentration. The photolysis rate of HONO was estimated, suggesting that the larger number of OH radicals resulting from high concentrations of HONO have a considerable impact on ozone concentrations. PMID:26121146

Changes in southern Piedmont grassland community structure and nutritive quality with future climate scenarios of elevated tropospheric ozone and altered rainfall patterns.

PubMed

Gilliland, N J; Chappelka, A H; Muntifering, R B; Ditchkoff, S S

2016-01-01

Forage species common to the southern USA Piedmont region, Lolium arundinacea, Paspalum dilatatum, Cynodon dactylon and Trifolium repens, were established in a model pasture system to test the future climate change scenario of increasing ozone exposure in combination with varying rainfall amounts on community structure and nutritive quality. Forages were exposed to two levels of ozone [ambient (non-filtered; NF) and twice ambient (2×) concentrations] with three levels of precipitation (average or ±20% of average) in modified open-top chambers (OTCs) from June to September 2009. Dry matter (DM) yield did not differ over the growing season between forage types, except in primary growth grasses where DM yield was higher in 2× than NF treatment. Primary growth clover decreased in nutritive quality in 2× ozone because of increased concentrations of neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL). Re-growth clover exhibited the largest decrease in nutritive quality, whereas grasses were not adversely affected in 2× ozone. Re-growth grasses responded positively to 2× ozone exposure, as indicated in increased relative food value (RFV) and percentage crude protein (CP) than NF-exposed re-growth grasses. Effects of precipitation were not significant over the growing season for primary or re-growth forage, except in primary growth grasses where DM yield was higher in chambers with above average (+20%) precipitation. Total canopy cover was significantly higher over the growing season in chambers receiving above average precipitation, but no significant effects were observed with ozone. Results indicate shifts in plant community structure and functioning related to mammalian herbivore herbivory in future climate change scenarios. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

Influence of Chlorine Emissions on Ozone Levels in the Troposphere

EPA Science Inventory

Chlorine emissions from cooling towers are emitted mainly as hypochlous acid, not as molecular chlorine. Chlorine emissions from cooling towers in electric utilities in the U.S. are estimated to be 4,400 tons per year. Molecular chlorine increases more tropospheric ozone than hyp...

Projecting the Influence of Climate Change on Extreme Ground-level Ozone Events in Selected Ontario Cities =

NASA Astrophysics Data System (ADS)

Leung, Kinson He Yin

Ground-level ozone (O3) is perhaps one of the most familiar pollutants in Ontario, Canada because it is associated with most smog alerts in the province. O3 varies on a number of spatial and temporal scales, primarily due to meteorological variability and the impact of long-range transport of its precursors on the photochemical processes. The goal of this thesis is to project the change in the probability of occurrence of future Extreme Ground-level Ozone Events (EGLOEs) due to changes in atmospheric conditions as a result of climate change for cities located in the southern, eastern and northern parts of Ontario, Canada by using a combination of General Circulation / Global Climate Models (GCMs) and statistical downscaling. These Ontario cities are Toronto, Windsor, London, Kingston, Ottawa, Thunder Bay, Sudbury and North Bay. The successful downscaling method used in this research to generate city-specific climate change scenarios was the Statistical DownScaling Model (SDSM) version 4.2.2, which is a hybrid of regression-based and stochastic weather-generator downscaling methods. The results indicate that the mean values of the daily maximum ground-level ozone concentrations could increase by up to 12-17% in Southern Ontario, 8-16% in Eastern Ontario and 1.5-9% in Northern Ontario by the end of the century due largely to changes in long-range transport. Three important themes emerge from the results: 1) the research successfully model O3 concentration in a region where long-range transport plays a substantial role. 2) The clear confirmation regarding the role of long-range transport in determining O 3 concentration in most areas of Ontario. 3) The projected increase of ozone in Ontario, due largely to an increase of long-range transport, caused by shifting atmospheric dynamics rather than a direct temperature effect on ozone production. Moreover, the results indicate that the future Southern, Eastern and Northern Ontario's EGLOEs with the O3 concentration ≥ 80 ppb (the current Ontario 1-hour Ambient Air Quality criterion for extreme ozone concentration) will have an increase of over 60%, 50% and 62% respectively by the year of 2100 under the different future scenarios in the third version of the Coupled Global Climate Model (CGCM3) and the Hadley Centre's Climate Model (HadCM3).

Comparative evaluation of effects of ozonated and chlorinated thermal discharges on estuarine and fresh water organisms. First quarterly progress report, April 1979

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guerra, C.R.; DelMonaco, J.L.; Singletary, J.H.

1979-01-01

The biological evaluation program incorporates three types of experimental tests: acute (96 hour) toxicity studies; behavioral (avoidance) response studies; and physiological (cough) response studies. In addition, specimens used in testing are examined for physical damage resulting from exposure to chlorine or ozoen. The objective of the acute (96 hour) toxicity study is to determine the respective lethal levels (LC/sub 50/) of chlorinated and ozonated waters. The objective of the behavioral (avoidance) response study is to determine what (if any) concentrations of ozone and of chlorine will be avoided. The objective of physiological (cough) response study is to determine what concentrationsmore » of ozone and of chlorine are physiologically detected. Ozonated and chlorinated waters were evaluated in all studies for both the addition of increased temperature and without it. Results indicate that ozone is less toxic than chlorine under the test conditions used. The lethal levels vary according to species of water quality measurements at Bergen Generating Station, New York are tabulated. (JBG)« less

Seasonal evaluation of disinfection by-products throughout two full-scale drinking water treatment plants.

PubMed

Zhong, Xin; Cui, Chongwei; Yu, Shuili

2017-07-01

Carbonyl compounds can occur alpha-hydrogens or beta-diketones substitution reactions with disinfectants contributed to halogenated by-products formation. The objective of this research was to study the occurrence and fate of carbonyl compounds as ozonation by-products at two full-scale drinking water treatment plants (DWTPs) using different disinfectants for one year. The quality of the raw water used in both plants was varied according to the season. The higher carbonyl compounds concentrations were found in raw water in spring. Up to 15 (as the sum of both DWTPs) of the 24 carbonyl compounds selected for this work were found after disinfection. The dominant carbonyl compounds were formaldehyde, glyoxal, methyl-glyoxal, fumaric, benzoic, protocatechuic and 3-hydroxybenzoic acid at both DWTPs. In the following steps in each treatment plant, the concentration patterns of these carbonyl compounds differed depending on the type of disinfectant applied. Benzaldehyde was the only aromatic aldehyde detected after oxidation with ozone in spring. As compared with DWTP 1, five new carbonyl compounds were formed (crotonaldehyde, benzaldehyde, formic, oxalic and malonic acid) disinfection by ozone, and the levels of the carbonyl compounds increased. In addition, pre-ozonation (PO) and main ozonation (OZ) increased the levels of carbonyl compounds, however coagulation/flocculation (CF), sand filtration (SF) and granular activated carbon filtration (GAC) decreased the levels of carbonyl compounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

Peroxidase Release Induced by Ozone in Sedum album Leaves

PubMed Central

Castillo, Federico J.; Penel, Claude; Greppin, Hubert

1984-01-01

The effect of ozone was studied on the peroxidase activity from various compartments of Sedum album leaves (epidermis, intercellular fluid, residual cell material, and total cell material). The greatest increase following a 2-hour ozone exposure (0.4 microliters O3 per liter) was observed in extracellular peroxidases. Most of the main bands of peroxidase activity separated by isoelectric focusing exhibited an increase upon exposure to ozone. Incubation experiments with isolated peeled or unpeeled leaves showed that leaves from ozone-treated plants release much more peroxidases in the medium than untreated leaves. The withdrawal of Ca2+ ions reduced the level of extracellular peroxidase activity either in whole plants or in incubation experiments. This reduction and the activation obtained after addition of Ca2+ resulted from a direct requirement of Ca2+ by the enzyme and from an effect of Ca2+ on peroxidase secretion. The ionophore A23187 promoted an increase of extracellular peroxidase activity only in untreated plants. The release of peroxidases by untreated and ozone-treated leaves is considerably lowered by metabolic inhibitors (3-(3,4-dichlorophenyl)-1,1-dimethylurea and sodium azide) and by puromycin. Images Fig. 1 PMID:16663520

Treatment of wastewater containing o-phenylenediamine by ozone in a rotor-stator reactor.

PubMed

Arowo, Moses; Li, Yingwen; Chu, Guangwen; Sun, Baochang; Chen, Jianfeng; Shao, Lei

2016-01-01

This work employed a novel rotor-stator reactor (RSR) to intensify the degradation process of o-phenylenediamine (o-PDA) by ozone. The effects of different operating parameters including initial pH, temperature, rotation speed, liquid volumetric flow rate and inlet ozone concentration on the removal efficiency of o-PDA were investigated in an attempt to establish the optimum conditions. The removal efficiency was evaluated in terms of degradation ratio and chemical oxygen demand (COD) reduction ratio of the o-PDA wastewater. Results indicate that the removal efficiency decreased with increasing liquid volumetric flow rate but increased with an increase in pH and inlet ozone concentration. Also, the removal efficiency increased up to a certain level with an increase in rotation speed and temperature. Additionally, a comparison experiment was carried out in a stirred tank reactor (STR), and the results show that the degradation and COD reduction ratios reached a maximum of 94.6% and 61.2% in the RSR as compared to 45.3% and 28.6% in the STR, respectively. This work demonstrates that ozone oxidation carried out in RSR may be a promising alternative for pre-treatment of o-PDA wastewater.

An Update on Ozone Profile Trends for the Period 2000 to 2016

NASA Technical Reports Server (NTRS)

Steinbrecht, Wolfgang; Froidevaux, Lucien; Fuller, Ryan; Wang, Ray; Anderson, John; Roth, Chris; Bourassa, Adam; Degenstein, Doug; Damadeo, Robert; Zawodny, Joe;

Remedial Process Optimization and Green In-Situ Ozone Sparging for Treatment of Groundwater Impacted with Petroleum Hydrocarbons

NASA Astrophysics Data System (ADS)

Leu, J.

2012-12-01

A former natural gas processing station is impacted with TPH and BTEX in groundwater. Air sparging and soil vapor extraction (AS/AVE) remediation systems had previously been operated at the site. Currently, a groundwater extraction and treatment system is operated to remove the chemicals of concern (COC) and contain the groundwater plume from migrating offsite. A remedial process optimization (RPO) was conducted to evaluate the effectiveness of historic and current remedial activities and recommend an approach to optimize the remedial activities. The RPO concluded that both the AS/SVE system and the groundwater extraction system have reached the practical limits of COC mass removal and COC concentration reduction. The RPO recommended an in-situ chemical oxidation (ISCO) study to evaluate the best ISCO oxidant and approach. An ISCO bench test was conducted to evaluate COC removal efficiency and secondary impacts to recommend an application dosage. Ozone was selected among four oxidants based on implementability, effectiveness, safety, and media impacts. The bench test concluded that ozone demand was 8 to 12 mg ozone/mg TPH and secondary groundwater by-products of ISCO include hexavalent chromium and bromate. The pH also increased moderately during ozone sparging and the TDS increased by approximately 20% after 48 hours of ozone treatment. Prior to the ISCO pilot study, a capture zone analysis (CZA) was conducted to ensure containment of the injected oxidant within the existing groundwater extraction system. The CZA was conducted through a groundwater flow modeling using MODFLOW. The model indicated that 85%, 90%, and 95% of an injected oxidant could be captured when a well pair is injecting and extracting at 2, 5, and 10 gallons per minute, respectively. An ISCO pilot test using ozone was conducted to evaluate operation parameters for ozone delivery. The ozone sparging system consisted of an ozone generator capable of delivering 6 lbs/day ozone through two ozone sparging wells. Startup test was conducted to optimize sparging pressure and flow rate and evaluate radius of influence (ROI) and pulsed sparging frequency. The startup test results indicated the system is optimized at 6 psi pressure and 3 cfm flow rate at ozone sparging rate of 2 lbs/day at each sparging location. The results also indicated a maximized ROI of 20 ft was reached and pulsed sparging frequency was estimated to be 60 minutes. The results at the completion of the pilot test concluded that TPH concentrations in groundwater decreased by 97% during the two months of ozone sparging, but did rebound to near baseline levels for most groundwater monitoring wells. Concentrations of hexavalent chromium and bromate increased from non-detect to 44 and 110 μg/L, respectively, during the ozone sparging but attenuated to non-detect concentrations within three months following the system shut down. Field measurements during the pilot study displayed an increasing trend of both oxidation-reduction potential (ORP) and dissolved oxygen (DO). After ozone sparging was complete, the ORP and DO in the saturated zone returned to near baseline levels. Based on the results of the pilot study, a full scale ISCO using ozone system was recommended.

Sea ice protects the embryos of the Antarctic sea urchin Sterechinus neumayeri from oxidative damage due to naturally enhanced levels of UV-B radiation.

PubMed

Lister, Kathryn N; Lamare, Miles D; Burritt, David J

2010-06-01

The 'ozone hole' has caused an increase in ultraviolet B radiation (UV-B, 280-320 nm) penetrating Antarctic coastal marine ecosystems, however the direct effect of this enhanced UV-B on pelagic organisms remains unclear. Oxidative stress, the in vivo production of reactive oxygen species to levels high enough to overcome anti-oxidant defences, is a key outcome of exposure to solar radiation, yet to date few studies have examined this physiological response in Antarctic marine species in situ or in direct relation to the ozone hole. To assess the biological effects of UV-B, in situ experiments were conducted at Cape Armitage in McMurdo Sound, Antarctica (77.06 degrees S, 164.42 degrees E) on the common Antarctic sea urchin Sterechinus neumayeri Meissner (Echinoidea) over two consecutive 4-day periods in the spring of 2008 (26-30 October and 1-5 November). The presence of the ozone hole, and a corresponding increase in UV-B exposure, resulted in unequivocal increases in oxidative damage to lipids and proteins, and developmental abnormality in embryos of S. neumayeri growing in open waters. Results also indicate that embryos have only a limited capacity to increase the activities of protective antioxidant enzymes, but not to levels sufficient to prevent severe oxidative damage from occurring. Importantly, results show that the effect of the ozone hole is largely mitigated by sea ice coverage. The present findings suggest that the coincidence of reduced stratospheric ozone and a reduction in sea ice coverage may produce a situation in which significant damage to Antarctic marine ecosystems may occur.

Reducing bacterial contamination in fuel ethanol fermentations by ozone treatment of uncooked corn mash.

PubMed

Rasmussen, Mary L; Koziel, Jacek A; Jane, Jay-lin; Pometto, Anthony L

2015-06-03

Ozonation of uncooked corn mash from the POET BPX process was investigated as a potential disinfection method for reducing bacterial contamination prior to ethanol fermentation. Corn mash (200 g) was prepared from POET ground corn and POET corn slurry and was ozonated in 250 mL polypropylene bottles. Lactic and acetic acid levels were monitored daily during the fermentation of ozonated, aerated, and nontreated corn mash samples to evaluate bacterial activity. Glycerol and ethanol contents of fermentation samples were checked daily to assess yeast activity. No yeast supplementation, no addition of other antimicrobial agents (such as antibiotics), and spiking with a common lactic acid bacterium found in corn ethanol plants, Lactobacillus plantarum, amplified the treatment effects. The laboratory-scale ozone dosages ranged from 26-188 mg/L, with very low estimated costs of $0.0008-0.006/gal ($0.21-1.6/m(3)) of ethanol. Ozonation was found to decrease the initial pH of ground corn mash samples, which could reduce the sulfuric acid required to adjust the pH prior to ethanol fermentation. Lactic and acetic acid levels tended to be lower for samples subjected to increasing ozone dosages, indicating less bacterial activity. The lower ozone dosages in the range applied achieved higher ethanol yields. Preliminary experiments on ozonating POET corn slurry at low ozone dosages were not as effective as using POET ground corn, possibly because corn slurry samples contained recycled antimicrobials from the backset. The data suggest additional dissolved and suspended organic materials from the backset consumed the ozone or shielded the bacteria.

Ozone exposure and daily mortality in Mexico City: a time-series analysis.

PubMed

Loomis, D P; Borja-Aburto, V H; Bangdiwala, S I; Shy, C M

1996-10-01

Daily death counts in Mexico City were examined in relation to ambient ozone levels during 1990-1992 for the purpose of investigating the acute, irreversible effects of air pollution, with emphasis on ozone exposure. Air pollution data were obtained from nine monitoring stations operated by the Departamento del Distrito Federal. Mortality data were provided by the Instituto Nacional de Estadística, Geografía, e Informática. Increases in numbers of deaths were positively associated with elevated air pollution levels on the same day and on the previous day. The magnitude of the increases was small but statistically significant, after Poisson regression models were used to adjust for temperature and long-term trends. In models using data for a single pollutant, the "crude" ratio for total mortality associated with an increase of 100 parts per billion (ppb)* in one-hour maximum ozone concentration was 1.029 (95% CI 1.015, 1.044). A moving average of ozone showed a stronger association (rate ratio [RR] = 1.048, 95% CI 1.025, 1.070), and excess mortality (an increase in the number of deaths, relative to the average on days with low pollution levels) was more evident for persons over 65 years of age. Separate analyses of the effect of elevated ozone for different areas of the city showed similar results, but they were not statistically significant. Other pollutants also were related to mortality. The RR was 1.075 (95% CI 0.984, 1.062) per 100-ppb increase for sulfur dioxide and 1.049 (95% CI 1.030, 1.067) per 100 micrograms/m3 increase in total suspended particulates (TSP) when these pollutants were considered in separate models. However, when all three pollutants were considered simultaneously, only TSP remained associated with mortality, indicating excess mortality of 5% per 100 micrograms/m3 increase [RR = 1.052, 95% CI 1.034, 1.072]. The excess mortality associated with TSP is consistent with that observed in other cities in America and Europe. This study provides some evidence that ozone is associated with all-cause mortality and with mortality among the elderly after controlling for long-term cycles. However, ozone levels exhibited little or no effect on mortality rates when other air pollutants were considered simultaneously. Particulate matter appeared to be an important pollutant; it independently predicted changes in mortality. Nevertheless, because of the complexity and variability of the mixtures to which people are exposed, it is difficult to attribute the observed effects to a single pollutant. The technical feasibility and scientific validity of isolating the effect of single pollutants in such complex mixtures requires further research and careful consideration. Given the large population living in and exposed to ambient air pollution in Mexico City and other metropolises throughout the world, these small but significant associations of mortality with air pollution indices are of public health concern.

Influence of enhanced Asian NOx emissions on ozone in the upper troposphere and lower stratosphere in chemistry-climate model simulations

NASA Astrophysics Data System (ADS)

Roy, Chaitri; Fadnavis, Suvarna; Müller, Rolf; Ayantika, D. C.; Ploeger, Felix; Rap, Alexandru

2017-01-01

The Asian summer monsoon (ASM) anticyclone is the most pronounced circulation pattern in the upper troposphere and lower stratosphere (UTLS) during northern hemispheric summer. ASM convection plays an important role in efficient vertical transport from the surface to the upper-level anticyclone. In this paper we investigate the potential impact of enhanced anthropogenic nitrogen oxide (NOx) emissions on the distribution of ozone in the UTLS using the fully coupled aerosol-chemistry-climate model, ECHAM5-HAMMOZ. Ozone in the UTLS is influenced both by the convective uplift of ozone precursors and by the uplift of enhanced-NOx-induced tropospheric ozone anomalies. We performed anthropogenic NOx emission sensitivity experiments over India and China. In these simulations, covering the years 2000-2010, anthropogenic NOx emissions have been increased by 38 % over India and by 73 % over China with respect to the emission base year 2000. These emission increases are comparable to the observed linear trends of 3.8 % per year over India and 7.3 % per year over China during the period 2000 to 2010. Enhanced NOx emissions over India by 38 % and China by 73 % increase the ozone radiative forcing in the ASM anticyclone (15-40° N, 60-120° E) by 16.3 and 78.5 mW m-2 respectively. These elevated NOx emissions produce significant warming over the Tibetan Plateau and increase precipitation over India due to a strengthening of the monsoon Hadley circulation. However, increase in NOx emissions over India by 73 % (similar to the observed increase over China) results in large ozone production over the Indo-Gangetic Plain and Tibetan Plateau. The higher ozone concentrations, in turn, induce a reversed monsoon Hadley circulation and negative precipitation anomalies over India. The associated subsidence suppresses vertical transport of NOx and ozone into the ASM anticyclone.

Quantitative analysis of interaction between the free troposphere and planetary boundary layer using multiple measurements and large eddy simulation model

NASA Astrophysics Data System (ADS)

Huang, Guanyu

We investigate the interaction between the free troposphere (FT) and planetary boundary layer (PBL) using multiple measurements and Dutch Atmospheric Large Eddy Simulation (DALES) coupled with a chemical module. A residual layer (RL) storing high ozone concentrations can significantly influence ground ozone concentration through the entrainment process whereby the RL aloft is incorporated into the growing convective boundary layer (CBL) during the morning transition. We use DALES model coupled with a chemical module to simultaneously study the dynamical and chemical impacts of a RL (200-1200 m above ground level (AGL)) on ground-level (0-200 m AGL) ozone concentrations. Four numerical experiments test these interactions: 1) a RL with high ozone (100 ppb); 2) a RL with low ozone (50 ppb); 3) no RL with high ozone above the NBL (100 ppb from 200-1200 m AGL); and 4) no RL with low ozone above the NBL (50 ppb). The results indicate that ozone stored in the RL can contribute up to 86% of the ozone concentration in the CBL during the following day in Case 1. Even in Case 2, 64% of the ozone in the developed CBL results from intrusions from the RL. Additionally, a RL also increases the enhancement rate of ozone in the CBL. Furthermore, we investigate the ozone diurnal variation on September 6, 2013 in Huntsville AL. The ozone variation in the CBL is mainly caused by local emissions due to the weather conditions being controlled by an anticyclonic system. The local chemical production contributes over 67% of the ozone enhancement in the CBL. The dynamical processes contribute the rest. The numerical experiments show good agreement with our ozone lidar observations. However, our simulation results and ozone lidar observations fail to reproduce a declining trend of surface ozone measured by an Environment Protection Agency (EPA) surface monitoring station that is 6 km south of our facilities, which is very likely due to the large ozone horizontal variation and the diurnal variation of ozone dry deposition under urban environment.

Ecological issues related to ozone: agricultural issues.

PubMed

Fuhrer, Jürg; Booker, Fitzgerald

2003-06-01

Research on the effects of ozone on agricultural crops and agro-ecosystems is needed for the development of regional emission reduction strategies, to underpin practical recommendations aiming to increase the sustainability of agricultural land management in a changing environment, and to secure food supply in regions with rapidly growing populations. Major limitations in current knowledge exist in several areas: (1) Modelling of ozone transfer and specifically stomatal ozone uptake under variable environmental conditions, using robust and well-validated dynamic models that can be linked to large-scale photochemical models lack coverage. (2) Processes involved in the initial reactions of ozone with extracellular and cellular components after entry through the stomata, and identification of key chemical species and their role in detoxification require additional study. (3) Scaling the effects from the level of individual cells to the whole-plant requires, for instance, a better understanding of the effects of ozone on carbon transport within the plant. (4) Implications of long-term ozone effects on community and whole-ecosystem level processes, with an emphasis on crop quality, element cycling and carbon sequestration, and biodiversity of pastures and rangelands require renewed efforts. The UNECE Convention on Long Range Trans-boundary Air Pollution shows, for example, that policy decisions may require the use of integrated assessment models. These models depend on quantitative exposure-response information to link quantitative effects at each level of organization to an effective ozone dose (i.e., the balance between the rate of ozone uptake by the foliage and the rate of ozone detoxification). In order to be effective in a policy, or technological context, results from future research must be funnelled into an appropriate knowledge transfer scheme. This requires data synthesis, up-scaling, and spatial aggregation. At the research level, interactions must be considered between the effects of ozone and factors that are either directly manipulated by man through crop management, or indirectly changed. The latter include elevated atmospheric CO(2), particulate matter, other pollutants such as nitrogen oxides, UV-B radiation, climate and associated soil moisture conditions.

Ground-Level Ozone Following Astrophysical Ionizing Radiation Events: An Additional Biological Hazard?

PubMed

Thomas, Brian C; Goracke, Byron D

2016-01-01

Astrophysical ionizing radiation events such as supernovae, gamma-ray bursts, and solar proton events have been recognized as a potential threat to life on Earth, primarily through depletion of stratospheric ozone and subsequent increase in solar UV radiation at Earth's surface and in the upper levels of the ocean. Other work has also considered the potential impact of nitric acid rainout, concluding that no significant threat is likely. Not yet studied to date is the potential impact of ozone produced in the lower atmosphere following an ionizing radiation event. Ozone is a known irritant to organisms on land and in water and therefore may be a significant additional hazard. Using previously completed atmospheric chemistry modeling, we examined the amount of ozone produced in the lower atmosphere for the case of a gamma-ray burst and found that the values are too small to pose a significant additional threat to the biosphere. These results may be extended to other ionizing radiation events, including supernovae and extreme solar proton events.

Record low total ozone during northern winters of 1992 and 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bojkov, R.D.

1993-07-09

The authors look at recorded ozone data over the northern hemisphere during the winters of 1992 and 1993. They use data from the World Meteorological Organization data base. During both of these winter, there have been marked decreases in the column ozone levels over North America, Europe, and Siberia, in the latitude belt from 45[degrees]N to 65[degrees]N. During these winters there have been ten times as many days with ozone levels deviated more than 2[sigma] below the 35 year average. They seek explanations for these observations by looking at meterological information. Evidences indicate that there was transport of ozone deficientmore » air masses during these winters. In addition cold air masses with excess ClO show evidence of having transported into the more southern latitudes. The authors conclude there is evidence for both displacement of large air masses, and increased chemical destruction potential, to have contributed to these observed decreases.« less

Airborne LIDAR Measurements of Aerosol and Ozone Above the Alberta Oil Sands Region

NASA Astrophysics Data System (ADS)

Aggarwal, M.; Whiteway, J. A.; Seabrook, J.; Gray, L. H.

2014-12-01

Lidar measurements of ozone and aerosol were conducted from a Twin Otter aircraft above the oil sands region of northern Alberta. The field campaign was carried out with a total of five flights out of Fort McMurray, Alberta during the period between August 22 and August 26, 2013. Significant amounts of aerosol were observed within the boundary layer, up to a height of 1.6 km, but the ozone concentration remained at or below background levels. On August 24th the lidar observed a separated layer of aerosol above the boundary layer, at a height of 1.8 km, in which the ozone mixing ratio increased to 70 ppbv. Backward trajectory calculations revealed that the air containing this separated aerosol layer had passed over an area of forest fires. Directly below the layer of forest fire smoke, in the pollution from the oil sands industry, the measured ozone mixing ratio was lower than the background levels (≤35 ppbv).

Impact of biogenic very short-lived bromine on the Antarctic ozone hole during the 21st century

NASA Astrophysics Data System (ADS)

Fernandez, Rafael Pedro; Kinnison, Douglas E.; Lamarque, Jean-Francois; Tilmes, Simone; Saiz-Lopez, Alfonso

2017-04-01

Active bromine released from the photochemical decomposition of biogenic very short-lived bromocarbons (VSLBr) enhances stratospheric ozone depletion. Based on a dual set of 1960-2100 coupled chemistry-climate simulations (i.e. with and without VSLBr), we show that the maximum Antarctic ozone hole depletion increases by up to 14% when natural VSLBr are considered, in better agreement with ozone observations. The impact of the additional 5 pptv VSLBr on Antarctic ozone is most evident in the periphery of the ozone hole, producing an expansion of the ozone hole area of 5 million km2, which is equivalent in magnitude to the recently estimated Antarctic ozone healing due to the implementation of the Montreal Protocol. We find that the inclusion of VSLBr in CAM-Chem does not introduce a significant delay of the modelled ozone return date to 1980 October levels, but instead affect the depth and duration of the simulated ozone hole. Our analysis further shows that total bromine-catalysed ozone destruction in the lower stratosphere surpasses that of chlorine by year 2070, and indicates that natural VSLBr chemistry would dominate Antarctic ozone seasonality before the end of the 21st century. This work suggests a large influence of biogenic bromine on the future Antarctic ozone layer.

Impacts of rising tropospheric ozone on photosynthesis and metabolite levels on field grown soybean.

PubMed

Sun, Jindong; Feng, Zhaozhong; Ort, Donald R

2014-09-01

The response of leaf photosynthesis and metabolite profiles to ozone (O3) exposure ranging from 37 to 116 ppb was investigated in two soybean cultivars Dwight and IA3010 in the field under fully open-air conditions. Leaf photosynthesis, total non-structural carbohydrates (TNC) and total free amino acids (TAA) decreased linearly with increasing O3 levels in both cultivars with average decrease of 7% for an increase in O3 levels by 10 ppb. Ozone interacted with developmental stages and leaf ages, and caused higher damage at later reproductive stages and in older leaves. Ozone affected yield mainly via reduction of maximum rate of Rubisco carboxylation (Vcmax) and maximum rates of electron transport (Jmax) as well as a shorter growing season due to earlier onset of canopy senescence. For all parameters investigated the critical O3 levels (∼50 ppb) for detectable damage fell within O3 levels that occur routinely in soybean fields across the US and elsewhere in the world. Strong correlations were observed in O3-induced changes among yield, photosynthesis, TNC, TAA and many metabolites. The broad range of metabolites that showed O3 dose dependent effect is consistent with multiple interaction loci and thus multiple targets for improving the tolerance of soybean to O3. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Source Attribution of Tropospheric Ozone using a Global Model

NASA Astrophysics Data System (ADS)

Coates, J.; Lupascu, A.; Butler, T. M.; Zhu, S.

2016-12-01

Tropospheric ozone is both a short-lived climate forcing pollutant and a radiatively active greenhouse gas. Ozone is not directly emitted into the troposphere but photochemically produced from chemical reactions involving nitrogen oxides (NOx) and volatile organic compounds (VOCs). Emissions of ozone precursors (NOx and VOCs) have both natural and anthropogenic sources and may be transported away from their sources to produce ozone downwind. Also, transport of ozone from the stratosphere into the troposphere also influences tropospheric ozone levels in some regions. Attributing ozone concentrations to the contributions from different sources would indicate the effects of locally emitted or transported precursors on ozone levels in specific regions. This information could be used to inform the emission reduction strategies of ozone precursors by indicating which emission sources could be targeted for effective reductions thus reducing the burden of ozone pollution. We use a "tagging" approach within the CESM global model to attribute ozone levels to their source emissions. We use different tags to quantify the impact from natural (soils, lightning, stratospheric transport) and anthropogenic (aircraft, biomass burning) sources of NOx and VOCs (including methane) on ozone levels. These source sectors of different global regions are assigned based on the global emissions specified by HTAPv2.2. Using these results, we develop a transboundary source-receptor relationship of ozone concentration to its precursor emission regions. Additionally, the transport of ozone precursors from regional anthropogenic sources is analysed to illustrate the extent to which mitigation strategies of regional emissions aid in mitigating global ozone levels.

Evaluation of soil pH and moisture content on in-situ ozonation of pyrene in soils.

PubMed

Luster-Teasley, S; Ubaka-Blackmoore, N; Masten, S J

2009-08-15

In this study, pyrene spiked soil (300 ppm) was ozonated at pH levels of 2, 6, and 8 and three moisture contents. It was found that soil pH and moisture content impacted the effectiveness of PAH oxidation in unsaturated soils. In air-dried soils, as pH increased, removal increased, such that pyrene removal efficiencies at pH 6 and pH 8 reached 95-97% at a dose of 2.22 mg O(3)/mg pyrene. Ozonation at 16.2+/-0.45 mg O(3)/ppm pyrene in soil resulted in 81-98% removal of pyrene at all pH levels tested. Saturated soils were tested at dry, 5% or 10% moisture conditions. The removal of pyrene was slower in moisturized soils, with the efficiency decreasing as the moisture content increased. Increasing the pH of the soil having a moisture content of 5% resulted in improved pyrene removals. On the contrary, in the soil having a moisture content of 10%, as the pH increased, pyrene removal decreased. Contaminated PAH soils were stored for 6 months to compare the efficiency of PAH removal in freshly contaminated soil and aged soils. PAH adsorption to soil was found to increase with longer exposure times; thus requiring much higher doses of ozone to effectively oxidize pyrene.

Control of bromate and THM precursors using ozonation combined system.

PubMed

Xie, Shu-Guang; Shi, Dong-Wen; Wen, Dong-Hui; Wang, Rui; Xi, Dan-Li

2007-06-01

To investigate the feasibility of reducing THM precursors and controlling bromate taste and odor in drinking water taken from the Yellow River by an ozonation combined system. The appropriate ozone dosage was determined, and then the changes of TOC, UV254 and THM formation potential (THMFP) in the combined system were evaluated. One mg/L ozone could effectively remove taste and odor and meet the maximum allowable bromate level in drinking water. The pre-ozonation increased THMFP, but the conventional treatment system could effectively reduce the odor. The bio-ceramic filter could partly reduce CHCl3FP, but sometimes might increase CHCl2BrFP and CHClBr2FP. The biological activated carbon (BAC) filter could effectively reduce CHCl3FP and CHCl2BrFP, but increase CHClBr2FP. Compared with other filters, the fresh activated carbon (FAC) filter performed better in reducing THMFP and even reduced CHClBr2FP. The combined system can effectively reduce taste, odor, CHCl3FP, and CHCl2BrFP and also bring bromate under control.

The changing oxidizing environment in London - trends in ozone precursors and their contribution to ozone production

NASA Astrophysics Data System (ADS)

von Schneidemesser, E.; Vieno, M.; Monks, P. S.

2014-01-01

Ground-level ozone is recognized to be a threat to human health (WHO, 2003), have a deleterious impact on vegetation (Fowler et al., 2009), is also an important greenhouse gas (IPCC, 2007) and key to the oxidative ability of the atmosphere (Monks et al., 2009). Owing to its harmful effect on health, much policy and mitigation effort has been put into reducing its precursors - the nitrogen oxides (NOx) and non-methane volatile organic compounds (NMVOCs). The non-linear chemistry of tropospheric ozone formation, dependent mainly on NOx and NMVOC concentrations in the atmosphere, makes controlling tropospheric ozone complex. Furthermore, the concentration of ozone at any given point is a complex superimposition of in-situ produced or destroyed ozone and transported ozone on the regional and hemispheric-scale. In order to effectively address ozone, a more detailed understanding of its origins is needed. Here we show that roughly half (5 μg m-3) of the observed increase in urban (London) ozone (10 μg m-3) in the UK from 1998 to 2008 is owing to factors of local origin, in particular, the change in NO : NO2 ratio, NMVOC : NOx balance, NMVOC speciation, and emission reductions (including NOx titration). In areas with previously higher large concentrations of nitrogen oxides, ozone that was previously suppressed by high concentrations of NO has now been "unmasked", as in London and other urban areas of the UK. The remaining half (approximately 5 μg m-3) of the observed ozone increase is attributed to non-local factors such as long-term transport of ozone, changes in background ozone, and meteorological variability. These results show that a two-pronged approach, local action and regional-to-hemispheric cooperation, is needed to reduce ozone and thereby population exposure, which is especially important for urban ozone.

Impact of Biogenic Emission Uncertainties on the Simulated Response of Ozone and Fine Particulate Matter to Anthropogenic Emission Reductions

PubMed Central

Hogrefe, Christian; Isukapalli, Sastry S.; Tang, Xiaogang; Georgopoulos, Panos G.; He, Shan; Zalewsky, Eric E.; Hao, Winston; Ku, Jia-Yeong; Key, Tonalee; Sistla, Gopal

2011-01-01

The role of emissions of volatile organic compounds and nitric oxide from biogenic sources is becoming increasingly important in regulatory air quality modeling as levels of anthropogenic emissions continue to decrease and stricter health-based air quality standards are being adopted. However, considerable uncertainties still exist in the current estimation methodologies for biogenic emissions. The impact of these uncertainties on ozone and fine particulate matter (PM2.5) levels for the eastern United States was studied, focusing on biogenic emissions estimates from two commonly used biogenic emission models, the Model of Emissions of Gases and Aerosols from Nature (MEGAN) and the Biogenic Emissions Inventory System (BEIS). Photochemical grid modeling simulations were performed for two scenarios: one reflecting present day conditions and the other reflecting a hypothetical future year with reductions in emissions of anthropogenic oxides of nitrogen (NOx). For ozone, the use of MEGAN emissions resulted in a higher ozone response to hypothetical anthropogenic NOx emission reductions compared with BEIS. Applying the current U.S. Environmental Protection Agency guidance on regulatory air quality modeling in conjunction with typical maximum ozone concentrations, the differences in estimated future year ozone design values (DVF) stemming from differences in biogenic emissions estimates were on the order of 4 parts per billion (ppb), corresponding to approximately 5% of the daily maximum 8-hr ozone National Ambient Air Quality Standard (NAAQS) of 75 ppb. For PM2.5, the differences were 0.1–0.25 μg/m3 in the summer total organic mass component of DVFs, corresponding to approximately 1–2% of the value of the annual PM2.5 NAAQS of 15 μg/m3. Spatial variations in the ozone and PM2.5 differences also reveal that the impacts of different biogenic emission estimates on ozone and PM2.5 levels are dependent on ambient levels of anthropogenic emissions. PMID:21305893

Effect of tibolone pretreatment on kinases and phosphatases that regulate the expression and phosphorylation of Tau in the hippocampus of rats exposed to ozone

PubMed Central

Pinto-Almazán, Rodolfo; Segura-Uribe, Julia J.; Soriano-Ursúa, Marvin A.; Farfán-García, Eunice D.; Gallardo, Juan M.; Guerra-Araiza, Christian

2018-01-01

Oxidative stress (OS) is a key process in the development of many neurodegenerative diseases, memory disorders, and other pathological processes related to aging. Tibolone (TIB), a synthetic hormone used as a treatment for menopausal symptoms, decreases lipoperoxidation levels, prevents memory impairment and learning disability caused by ozone (O3) exposure. However, it is not clear if TIB could prevent the increase in phosphorylation induced by oxidative stress of the microtubule-associated protein Tau. In this study, the effects of TIB at different times of administration on the phosphorylation of Tau, the activation of glycogen synthase kinase-3β (GSK3β), and the inactivation of Akt and phosphatases PP2A and PTEN induced by O3 exposure were assessed in adult male Wistar rats. Rats were divided into 10 groups: control group (ozone-free air plus vehicle [C]), control + TIB group (ozone-free air plus TIB 1 mg/kg [C + TIB]); 7, 15, 30, and 60 days of ozone exposure groups [O3] and 7, 15, 30, and 60 days of TIB 1 mg/kg before ozone exposure groups [O3 + TIB]. The effects of O3 exposure and TIB administration were assessed by western blot analysis of total and phosphorylated Tau, GSK3β, Akt, PP2A, and PTEN proteins and oxidative stress marker nitrotyrosine, and superoxide dismutase activity and lipid peroxidation of malondialdehyde by two different spectrophotometric methods (Marklund and TBARS, respectively). We observed that O3 exposure increases Tau phosphorylation, which is correlated with decreased PP2A and PTEN protein levels, diminished Akt protein levels, and increased GSK3β protein levels in the hippocampus of adult male rats. The effects of O3 exposure were prevented by the long-term treatment (over 15 days) with TIB. Malondialdehyde and nitrotyrosine levels increased from 15 to 60 days of exposure to O3 in comparison to C group, and superoxide dismutase activity decreased. Furthermore, TIB administration limited the changes induced by O3 exposure. Our results suggest a beneficial use of hormone replacement therapy with TIB to prevent neurodegeneration caused by O3 exposure in rats. PMID:29623928

Changes in air quality and tropospheric composition due to depletion of stratospheric ozone and interactions with changing climate: implications for human and environmental health.

PubMed

Madronich, S; Shao, M; Wilson, S R; Solomon, K R; Longstreth, J D; Tang, X Y

2015-01-01

UV radiation is an essential driver for the formation of photochemical smog, which includes ground-level ozone and particulate matter (PM). Recent analyses support earlier work showing that poor outdoor air quality is a major environmental hazard as well as quantifying health effects on regional and global scales more accurately. Greater exposure to these pollutants has been linked to increased risks of cardiovascular and respiratory diseases in humans and is associated globally with several million premature deaths per year. Ozone also has adverse effects on yields of crops, leading to loss of billions of US dollars each year. These detrimental effects also may alter biological diversity and affect the function of natural ecosystems. Future air quality will depend mostly on changes in emission of pollutants and their precursors, but changes in UV radiation and climate will contribute as well. Significant reductions in emissions, mainly from the energy and transportation sectors, have already led to improved air quality in many locations. Air quality will continue to improve in those cities/states that can afford controls, and worsen where the regulatory infrastructure is not available. Future changes in UV radiation and climate will alter the rates of formation of ground-level ozone and photochemically-generated particulate matter and must be considered in predictions of air quality. The decrease in UV radiation associated with recovery of stratospheric ozone will, according to recent global atmospheric model simulations, lead to increases in ground-level ozone at most locations. If correct, this will add significantly to future ground-level ozone trends. However, the spatial resolution of these global models is insufficient to inform policy at this time, especially for urban areas. UV radiation affects the atmospheric concentration of hydroxyl radicals, ˙OH, which are responsible for the self-cleaning of the atmosphere. Recent measurements confirm that, on a local scale, ˙OH radicals respond rapidly to changes in UV radiation. However, on large (global) scales, models differ in their predictions by nearly a factor of two, with consequent uncertainties for estimating the atmospheric lifetime and concentrations of key greenhouse gases and air pollutants. Projections of future climate need to consider these uncertainties. No new negative environmental effects of substitutes for ozone depleting substances or their breakdown-products have been identified. However, some substitutes for the ozone depleting substances will continue to contribute to global climate change if concentrations rise above current levels.

Large-scale protein analysis of European beech trees following four vegetation periods of twice ambient ozone exposure.

PubMed

Kerner, René; Delgado-Eckert, Edgar; Ernst, Dieter; Dupuy, Jean-William; Grams, Thorsten E E; Barbro Winkler, J; Lindermayr, Christian; Müller-Starck, Gerhard

2014-09-23

In the present study, we performed a large-scale protein analysis based on 2-DE DIGE to examine the effects of ozone on the leaves of juvenile European beech (Fagus sylvatica L.), one of the most important deciduous tree species in Central Europe. To this end, beech trees were grown under field conditions and subjected to ambient and twice ambient ozone concentrations during the vegetation periods of four consecutive years. The twice ambient ozone concentration altered the abundance of 237 protein spots, which showed relative ratios higher than 30% compared to the ambient control trees. A total of 74 protein spots were subjected to mass spectrometry identification (LC-MS/MS), followed by homology-driven searches. The differentially expressed proteins participate in key biological processes including the Calvin cycle and photosynthesis, carbon metabolism, defense- and stress-related responses, detoxification mechanisms, protein folding and degradation, and mechanisms involved in senescence. The ozone-induced responses provide evidence of a changing carbon metabolism and counteraction against increased levels of reactive oxygen species. This study provides useful information on how European beech, an economically and ecologically important tree species, reacts on the molecular level to increased ozone concentrations expected in the near future. The main emphasis in the present study was placed on identifying differentially abundant proteins after long-term ozone exposure under climatically realistic settings, rather than short-term responses or reactions under laboratory conditions. Additionally, using nursery-grown beech trees, we took into account the natural genotypic variation of this species. As such, the results presented here provide information on molecular responses to ozone in an experimental plant system at very close to natural conditions. Furthermore, this proteomic approach was supported by previous studies on the present experiment. Ultimately, the combination of this proteomic approach with several approaches including transcriptomics, analysis of non-structural carbohydrates, and morphological effects contributes to a more global picture of how beech trees react under increased ozone concentrations. Copyright © 2014. Published by Elsevier B.V.

Understanding Ozone: Exploring the Good and Bad Facets of a Famous Gas.

ERIC Educational Resources Information Center

Hanif, Muhammad

1995-01-01

Presents activities that help students distinguish between the beneficial layer of stratospheric ozone and the dangerous ground-level or tropospheric ozone, understand the chemical processes of ozone breakdown in the stratosphere, find the sources of ground-level ozone, and explore the differences in the patterns of ozone concentration over the…

Changes in leaf area, nitrogen content and canopy photosynthesis in soybean exposed to an ozone concentration gradient

USDA-ARS?s Scientific Manuscript database

Influences of ozone (O3) on light-saturated rates of photosynthesis in crop leaves have been well documented. To increase our understanding of O3 effects on individual- or stand level productivity, a mechanistic understanding of factors determining canopy photosynthesis is necessary. We used a canop...

Increased lung resistance after diesel particulate and ozone co-exposure not associated with enhanced lung inflammation in allergic mice*

EPA Science Inventory

Exposure to diesel exhaust particle matter (DEP) exacerbates asthma. Likewise, similar effects have been reported with exposure to the oxidizing air pollutant ozone (03) . Since levels of both pollutants in ambient air tend to be simultaneously elevated, we investigated the possi...

Prophylactic Ozone Administration Reduces Intestinal Mucosa Injury Induced by Intestinal Ischemia-Reperfusion in the Rat

PubMed Central

Onal, Ozkan; Yetisir, Fahri; Sarer, A. Ebru Salman; Zeybek, N. Dilara; Onal, C. Oztug; Yurekli, Banu; Celik, H. Tugrul; Sirma, Ayse; Kılıc, Mehmet

2015-01-01

Objectives. Intestinal ischemia-reperfusion injury is associated with mucosal damage and has a high rate of mortality. Various beneficial effects of ozone have been shown. The aim of the present study was to show the effects of ozone in ischemia reperfusion model in intestine. Material and Method. Twenty eight Wistar rats were randomized into four groups with seven rats in each group. Control group was administered serum physiologic (SF) intraperitoneally (ip) for five days. Ozone group was administered 1 mg/kg ozone ip for five days. Ischemia Reperfusion (IR) group underwent superior mesenteric artery occlusion for one hour and then reperfusion for two hours. Ozone + IR group was administered 1 mg/kg ozone ip for five days and at sixth day IR model was applied. Rats were anesthetized with ketamine∖xyzlazine and their intracardiac blood was drawn completely and they were sacrificed. Intestinal tissue samples were examined under light microscope. Levels of superoxide dismutase (SOD), catalase (CAT), glutathioneperoxidase (GSH-Px), malondyaldehide (MDA), and protein carbonyl (PCO) were analyzed in tissue samples. Total oxidant status (TOS), and total antioxidant capacity (TAC) were analyzed in blood samples. Data were evaluated statistically by Kruskal Wallis test. Results. In the ozone administered group, degree of intestinal injury was not different from the control group. IR caused an increase in intestinal injury score. The intestinal epithelium maintained its integrity and decrease in intestinal injury score was detected in Ozone + IR group. SOD, GSH-Px, and CAT values were high in ozone group and low in IR. TOS parameter was highest in the IR group and the TAC parameter was highest in the ozone group and lowest in the IR group. Conclusion. In the present study, IR model caused an increase in intestinal injury.In the present study, ozone administration had an effect improving IR associated tissue injury. In the present study, ozone therapy prevented intestine from ischemia reperfusion injury. It is thought that the therapeutic effect of ozone is associated with increase in antioxidant enzymes and protection of cells from oxidation and inflammation. PMID:26161005

Indoor secondary pollutants from cleaning product and air freshener use in the presence of ozone

NASA Astrophysics Data System (ADS)

Singer, Brett C.; Coleman, Beverly K.; Destaillats, Hugo; Hodgson, Alfred T.; Lunden, Melissa M.; Weschler, Charles J.; Nazaroff, William W.

This study investigated the formation of secondary pollutants resulting from household product use in the presence of ozone. Experiments were conducted in a 50-m 3 chamber simulating a residential room. The chamber was operated at conditions relevant to US residences in polluted areas during warm-weather seasons: an air exchange rate of 1.0 h -1 and an inlet ozone concentration of approximately 120 ppb, when included. Three products were used in separate experiments. An orange oil-based degreaser and a pine oil-based general-purpose cleaner were used for surface cleaning applications. A plug-in scented-oil air freshener (AFR) was operated for several days. Cleaning products were applied realistically with quantities scaled to simulate residential use rates. Concentrations of organic gases and secondary organic aerosol from the terpene-containing consumer products were measured with and without ozone introduction. In the absence of reactive chemicals, the chamber ozone level was approximately 60 ppb. Ozone was substantially consumed following cleaning product use, mainly by homogeneous reaction. For the AFR, ozone consumption was weaker and heterogeneous reaction with sorbed AFR-constituent VOCs was of similar magnitude to homogeneous reaction with continuously emitted constituents. Formaldehyde generation resulted from product use with ozone present, increasing indoor levels by the order of 10 ppb. Cleaning product use in the presence of ozone generated substantial fine particle concentrations (more than 100 μg m -3) in some experiments. Ozone consumption and elevated hydroxyl radical concentrations persisted for 10-12 h following brief cleaning events, indicating that secondary pollutant production can persist for extended periods.

Proteomic differences with and without ozone-exposure in a smoking-induced emphysema lung model

PubMed Central

Uh, Soo-Taek; Koo, So-My; Jang, An Soo; Park, Sung Woo; Choi, Jae Sung; Kim, Yong-Hoon

2015-01-01

Background/Aims Acute exacerbations in chronic obstructive pulmonary disease may be related to air pollution, of which ozone is an important constituent. In this study, we investigated the protein profiles associated with ozone-induced exacerbations in a smoking-induced emphysema model. Methods Mice were divided into the following groups: group I, no smoking and no ozone (NS + NO); group II, no smoking and ozone (NS + O); group III, smoking and no ozone (S + NO); and group IV, smoking and ozone (S + O). Bronchoalveolar lavage, the mean linear intercept (MLI) on hematoxylin and eosin staining, nano-liquid chromatography-tandem mass spectrometry (LC-MS/MS), and Western blotting analyses were performed. Results The MLIs of groups III (S + NO) and IV (S + O) (45 ± 2 and 44 ± 3 µm, respectively) were significantly higher than those of groups I (NS + NO) and II (NS + O) (26 ± 2 and 23 ± 2 µm, respectively; p < 0.05). Fourteen spots that showed significantly different intensities on image analyses of two-dimensional (2D) protein electrophoresis in group I (NS + NO) were identified by LC-MS/MS. The levels of six proteins were higher in group IV (S + O). The levels of vimentin, lactate dehydrogenase A, and triose phosphate isomerase were decreased by both smoking and ozone treatment in Western blotting and proteomic analyses. In contrast, TBC1 domain family 5 (TBC1D5) and lamin A were increased by both smoking and ozone treatment. Conclusions TBC1D5 could be a biomarker of ozone-induced lung injury in emphysema. PMID:25589837

Preliminary Analysis of Ozonesonde Data from Houston, TX as Part of INTEX-A, July - August 2004

NASA Astrophysics Data System (ADS)

Hersey, S.; Morris, G.; Fraser, M.; Holmes, C.; Thompson, A.; Kuscera, T.; Witte, J.

2004-12-01

The Houston area is well-known for its frequent levels of high ozone pollution. The extent of the pollution in Houston has important direct and indirect consequences for the local population, ranging from the cancelling of recess to increased rates of asthma to threats of fines and loss of transportation dollars for failure to comply with EPA standards. Despite these consequences, the Houston area has no established program to monitor ozone concentrations at any altitude in the atmosphere but the surface. During the period July 8 - August 12, we launched 25 ozonesondes that yielded data on the vertical distribution of ozone over the city of Houston as part of INTEX-A and a study sponsored by the Shell Center for Sustainable Development at Rice University. Combining ozonesonde data from Houston with a trajectory model from NASA Goddard provides a powerful approach to interpreting the data, including insight into local and remote contributions to Houston's ozone pollution. Analysis of our data show (1) the impact of remote wild fires on ozone levels above Houston, (2) the amount of ozone that develops over Houston in the course of one day, and (3) the extent of vertical mixing of Houston's ozone pollution, a factor in transport to areas downwind of the city.

Temporal and Spatial Variation in, and Population Exposure to, Summertime Ground-Level Ozone in Beijing

PubMed Central

Zheng, Youfei; Li, Ting; Wei, Li; Guan, Qing

2018-01-01

Ground-level ozone pollution in Beijing has been causing concern among the public due to the risks posed to human health. This study analyzed the temporal and spatial distribution of, and investigated population exposure to, ground-level ozone. We analyzed hourly ground-level ozone data from 35 ambient air quality monitoring sites, including urban, suburban, background, and traffic monitoring sites, during the summer in Beijing from 2014 to 2017. The results showed that the four-year mean ozone concentrations for urban, suburban, background, and traffic monitoring sites were 95.1, 99.8, 95.9, and 74.2 μg/m3, respectively. A total of 44, 43, 45, and 43 days exceeded the Chinese National Ambient Air Quality Standards (NAAQS) threshold for ground-level ozone in 2014, 2015, 2016, and 2017, respectively. The mean ozone concentration was higher in suburban sites than in urban sites, and the traffic monitoring sites had the lowest concentration. The diurnal variation in ground-level ozone concentration at the four types of monitoring sites displayed a single-peak curve. The peak and valley values occurred at 3:00–4:00 p.m. and 7:00 a.m., respectively. Spatially, ground-level ozone concentrations decreased in gradient from the north to the south. Population exposure levels were calculated based on ground-level ozone concentrations and population data. Approximately 50.38%, 44.85%, and 48.49% of the total population of Beijing were exposed to ground-level ozone concentrations exceeding the Chinese NAAQS threshold in 2014, 2015, and 2016, respectively. PMID:29596366

Temporal and Spatial Variation in, and Population Exposure to, Summertime Ground-Level Ozone in Beijing.

PubMed

Zhao, Hui; Zheng, Youfei; Li, Ting; Wei, Li; Guan, Qing

2018-03-29

Ground-level ozone pollution in Beijing has been causing concern among the public due to the risks posed to human health. This study analyzed the temporal and spatial distribution of, and investigated population exposure to, ground-level ozone. We analyzed hourly ground-level ozone data from 35 ambient air quality monitoring sites, including urban, suburban, background, and traffic monitoring sites, during the summer in Beijing from 2014 to 2017. The results showed that the four-year mean ozone concentrations for urban, suburban, background, and traffic monitoring sites were 95.1, 99.8, 95.9, and 74.2 μg/m³, respectively. A total of 44, 43, 45, and 43 days exceeded the Chinese National Ambient Air Quality Standards (NAAQS) threshold for ground-level ozone in 2014, 2015, 2016, and 2017, respectively. The mean ozone concentration was higher in suburban sites than in urban sites, and the traffic monitoring sites had the lowest concentration. The diurnal variation in ground-level ozone concentration at the four types of monitoring sites displayed a single-peak curve. The peak and valley values occurred at 3:00-4:00 p.m. and 7:00 a.m., respectively. Spatially, ground-level ozone concentrations decreased in gradient from the north to the south. Population exposure levels were calculated based on ground-level ozone concentrations and population data. Approximately 50.38%, 44.85%, and 48.49% of the total population of Beijing were exposed to ground-level ozone concentrations exceeding the Chinese NAAQS threshold in 2014, 2015, and 2016, respectively.

Association between outdoor ozone and compensated acute respiratory diseases among workers in Quebec (Canada).

PubMed

Adam-Poupart, Ariane; Labrèche, France; Busque, Marc-Antoine; Brand, Allan; Duguay, Patrice; Fournier, Michel; Zayed, Joseph; Smargiassi, Audrey

2015-01-01

Respiratory effects of ozone in the workplace have not been extensively studied. Our aim was to explore the relationship between daily average ozone levels and compensated acute respiratory problems among workers in Quebec between 2003 and 2010 using a time-stratified case-crossover design. Health data came from the Workers' Compensation Board. Daily concentrations of ozone were estimated using a spatiotemporal model. Conditional logistic regressions, with and without adjustment for temperature, were used to estimate odds ratios (ORs, per 1 ppb increase of ozone), and lag effects were assessed. Relationships with respiratory compensations in all industrial sectors were essentially null. Positive non-statistically significant associations were observed for outdoor sectors, and decreased after controlling for temperature (ORs of 0.98; 1.01 and 1.05 at Lags 0, 1 and 2 respectively). Considering the predicted increase of air pollutant concentrations in the context of climate change, closer investigation should be carried out on outdoor workers.

Association of Short-term Exposure to Air Pollution With Mortality in Older Adults.

PubMed

Di, Qian; Dai, Lingzhen; Wang, Yun; Zanobetti, Antonella; Choirat, Christine; Schwartz, Joel D; Dominici, Francesca

2017-12-26

The US Environmental Protection Agency is required to reexamine its National Ambient Air Quality Standards (NAAQS) every 5 years, but evidence of mortality risk is lacking at air pollution levels below the current daily NAAQS in unmonitored areas and for sensitive subgroups. To estimate the association between short-term exposures to ambient fine particulate matter (PM2.5) and ozone, and at levels below the current daily NAAQS, and mortality in the continental United States. Case-crossover design and conditional logistic regression to estimate the association between short-term exposures to PM2.5 and ozone (mean of daily exposure on the same day of death and 1 day prior) and mortality in 2-pollutant models. The study included the entire Medicare population from January 1, 2000, to December 31, 2012, residing in 39 182 zip codes. Daily PM2.5 and ozone levels in a 1-km × 1-km grid were estimated using published and validated air pollution prediction models based on land use, chemical transport modeling, and satellite remote sensing data. From these gridded exposures, daily exposures were calculated for every zip code in the United States. Warm-season ozone was defined as ozone levels for the months April to September of each year. All-cause mortality in the entire Medicare population from 2000 to 2012. During the study period, there were 22 433 862 million case days and 76 143 209 control days. Of all case and control days, 93.6% had PM2.5 levels below 25 μg/m3, during which 95.2% of deaths occurred (21 353 817 of 22 433 862), and 91.1% of days had ozone levels below 60 parts per billion, during which 93.4% of deaths occurred (20 955 387 of 22 433 862). The baseline daily mortality rates were 137.33 and 129.44 (per 1 million persons at risk per day) for the entire year and for the warm season, respectively. Each short-term increase of 10 μg/m3 in PM2.5 (adjusted by ozone) and 10 parts per billion (10-9) in warm-season ozone (adjusted by PM2.5) were statistically significantly associated with a relative increase of 1.05% (95% CI, 0.95%-1.15%) and 0.51% (95% CI, 0.41%-0.61%) in daily mortality rate, respectively. Absolute risk differences in daily mortality rate were 1.42 (95% CI, 1.29-1.56) and 0.66 (95% CI, 0.53-0.78) per 1 million persons at risk per day. There was no evidence of a threshold in the exposure-response relationship. In the US Medicare population from 2000 to 2012, short-term exposures to PM2.5 and warm-season ozone were significantly associated with increased risk of mortality. This risk occurred at levels below current national air quality standards, suggesting that these standards may need to be reevaluated.

Identifying controlling factors of ground-level ozone levels over southwestern Taiwan using a decision tree

NASA Astrophysics Data System (ADS)

Chu, Hone-Jay; Lin, Chuan-Yao; Liau, Churn-Jung; Kuo, Yi-Ming

2012-12-01

Kaohsiung City and the suburban region of southwestern Taiwan have suffered from severe air pollution since becoming the largest center of heavy industry in Taiwan. The complex process of ozone (O3) formation and its precursor compounds (the volatile organic compounds (VOCs) and nitrogen oxide (NOx) emissions), accompanied by meteorological conditions, make controlling ozone difficult. Using a decision tree is especially appropriate for analyzing time series data that contain ozone levels and meteorological and explanatory variables for ozone formation. Results show that dominant variables such as temperature, wind speed, VOCs, and NOx can play vital roles in describing ozone variations among observations. That temperature and wind speed are highly correlated with ozone levels indicates that these meteorological conditions largely affect ozone variability. The results also demonstrate that spatial heterogeneity of ozone patterns are in coastal and inland areas caused by sea-land breeze and pollutant sources during high ozone episodes over southwestern Taiwan. This study used a decision tree to obtain quantitative insight into spatial distributions of precursor compound emissions and effects of meteorological conditions on ozone levels that are useful for refining monitoring plans and developing management strategies.

Cerebrovascular pattern improved by ozone autohemotherapy: an entropy-based study on multiple sclerosis patients.

PubMed

Molinari, Filippo; Rimini, Daniele; Liboni, William; Acharya, U Rajendra; Franzini, Marianno; Pandolfi, Sergio; Ricevuti, Giovanni; Vaiano, Francesco; Valdenassi, Luigi; Simonetti, Vincenzo

2017-08-01

Ozone major autohemotherapy is effective in reducing the symptoms of multiple sclerosis (MS) patients, but its effects on brain are still not clear. In this work, we have monitored the changes in the cerebrovascular pattern of MS patients and normal subjects during major ozone autohemotherapy by using near-infrared spectroscopy (NIRS) as functional and vascular technique. NIRS signals are analyzed using a combination of time, time-frequency analysis and nonlinear analysis of intrinsic mode function signals obtained from empirical mode decomposition technique. Our results show that there is an improvement in the cerebrovascular pattern of all subjects indicated by increasing the entropy of the NIRS signals. Hence, we can conclude that the ozone therapy increases the brain metabolism and helps to recover from the lower activity levels which is predominant in MS patients.

On the Influence of Anthropogenic Forcings on Changes in the Stratospheric Mean Age

NASA Technical Reports Server (NTRS)

Oman, Luke; Waugh, Darryn W.; Pawson, Steven; Stolarski, Richard S.; Newman, Paul A.

2009-01-01

A common feature of stratospheric simulations of the past or future is an increase in tropical upwelling and a decrease in mean age. Possible causes or these changes include (1) increases in tropical sea surface temperatures (SSTs) driven by increases in well-mixed greenhouse gases (WMGHGs), (2) the direct radiative effect of increases in WMGHGs, and (3) changes in ozone. Here we examine a suite of simulations from the Goddard Earth Observing System chemistry-climate model (GEOS CCM) to isolate the relative role of these three factors. Our analysis indicates that all three factors cause changes in the mean age, but the relative impact of each factor depends on the time period analyzed. Over the past 30-40 years ozone depletion is the major factor causing the decrease in mean age, with negligible changes due to direct radiative impact of WMGHG's. However, ozone is predicted to recover back to 1970 levels during the next 50-60 years, and this causes an increase in the mean age, whereas the continued increase in SSTs from increased levels of WMGHGs and the direct radiative impact of WMGHGs will still cause a decrease in the mean age. The net impact of these factors will still result in a decreasing mean age although the rate will be smaller than that of the past. The decreases in mean age are primarily caused by increases in upwelling in the tropical lower stratosphere. The increased upwelling from both increased tropical SSTs and polar ozone loss appears to be related to changes in zonal winds and increases in wave activity propagating into the stratosphere. The different contributions of changes in SSTs, WMGHGs, and ozone to the circulation of the stratosphere may help explain the large spread in the rate of change of tropical upwelling seen in previous studies.

Preliminary Investigation of Cyclic Behavior at SHADOZ Sites Between the Equator and 5 deg S Latitude

NASA Technical Reports Server (NTRS)

Schmidlin, F. J.

2009-01-01

Investigation of cyclic behavior of temperature and ozone data from five SHADOZ sites between the Equator and 5degS Latitude (Nairobi, Ascension Island, Natal, San Crystobal, and Watukoset) reveal an amazing array of oscillations. In particular, eight years of measurements (1998-2007) reveal changes such as decreasing amounts of ozone at some pressure levels and/or sites, while other levels and/or sites experience increasing ozone. Temperature changes of 1-2 C occur that also experience irregular oscillations. This study is preliminary and only concentrates on the 250-, 200-, 100-, 70-, and 50-hPa pressure surfaces. Surfaces existing below and above the tropopause behave differently.

Issues in Stratospheric Ozone Depletion.

NASA Astrophysics Data System (ADS)

Lloyd, Steven Andrew

Following the announcement of the discovery of the Antarctic ozone hole in 1985 there have arisen a multitude of questions pertaining to the nature and consequences of polar ozone depletion. This thesis addresses several of these specific questions, using both computer models of chemical kinetics and the Earth's radiation field as well as laboratory kinetic experiments. A coupled chemical kinetic-radiative numerical model was developed to assist in the analysis of in situ field measurements of several radical and neutral species in the polar and mid-latitude lower stratosphere. Modeling was used in the analysis of enhanced polar ClO, mid-latitude diurnal variation of ClO, and simultaneous measurements of OH, HO_2, H_2 O and O_3. Most importantly, such modeling was instrumental in establishing the link between the observed ClO and BrO concentrations in the Antarctic polar vortex and the observed rate of ozone depletion. The principal medical concern of stratospheric ozone depletion is that ozone loss will lead to the enhancement of ground-level UV-B radiation. Global ozone climatology (40^circS to 50^ circN latitude) was incorporated into a radiation field model to calculate the biologically accumulated dosage (BAD) of UV-B radiation, integrated over days, months, and years. The slope of the annual BAD as a function of latitude was found to correspond to epidemiological data for non-melanoma skin cancers for 30^circ -50^circN. Various ozone loss scenarios were investigated. It was found that a small ozone loss in the tropics can provide as much additional biologically effective UV-B as a much larger ozone loss at higher latitudes. Also, for ozone depletions of > 5%, the BAD of UV-B increases exponentially with decreasing ozone levels. An important key player in determining whether polar ozone depletion can propagate into the populated mid-latitudes is chlorine nitrate, ClONO_2 . As yet this molecule is only indirectly accounted for in computer models and field measurements. Therefore a laboratory prototype of an instrument to measure ClONO _2 concentrations in situ was developed, adapting techniques recently developed in this research group to measure ClO concentrations at the part-per-trillion level. The detection scheme involves heating a flowing air sample to almost 500K, thermally dissociating ClONO _2 into ClO and NO_2 , and measuring the resulting ClO concentration by titrating with NO to produce Cl atoms, which are detected by resonance fluoresence. The calibration of this technique is very sensitive to flow parameters (temperature, pressure, flow velocity, added NO concentration, and homogeneity of flow). The issues developed in this thesis contribute to our understanding of the mechanisms of stratospheric ozone depletion and its potential global impact. It is becoming increasingly apparent that our ability to predict the future course of global ozone depletion is critically dependent on our ability to reproduce in situ and remote measurements with numerical models.

On the Relation between Atmospheric Ozone and Sunspot Number.

NASA Astrophysics Data System (ADS)

Angell, J. K.

1989-11-01

Based on data from the Dobson network, between 1960 and 1987 there has been a zero-lag correlation of 0.48 between the 112 unsmoothed seasonal values of sunspot number and global total ozone, significant at the 1% level taking into account the considerable serial correlation in these data. The maximum correlation of 0.54 is found when sunspot number lags total ozone by two seasons, the result mainly of a phase difference early in the record. On the basis of only 2 1/2 solar cycles, the global total ozone has increased by 1.4% for an increase in sunspot number of 100. The correlation between sunspot number and total ozone has been significant at the 5% level in north temperate and tropical zones-the zones with the most representative data. In the north temperate zone, the correlation between sunspot number and total ozone has been much higher in the west-wind phase of the 50 mb equatorial QBO than in the east-wind phase, but in the tropics the correlation has been much higher in the east-wind phase. Umkehr measurements between 1966 and 1987 in the north temperate zone indicate that the correlation between sunspot number and ozone amount has been higher (0.35, almost significant at the 5% level) in the low stratosphere where transport processes dominate than in the high stratosphere where photochemical processes dominate. During 1932-60 there was a significant correlation of 0.35 between sunspot number and Arosa total ozone 14 seasons later, very different from the nearly in-phase relation found after 1960. Considered is the possible impact of long-term change in transport processes in the low stratosphere on the total-ozone record at a single station such as Arosa.Between 1966 and 1985 there has been very good agreement between observed global total ozone, and global total ozone calculated from three 2-D stratospheric models that take into account the solar cycle, the time variation in trace gases, and nuclear tests; both observed and calculated variations are closely related to the variation in sunspot number. Between 1960 and 1966, however, the agreement between observation and calculation is poor, the models indicating a pronounced minimum in global total ozone in 1963 due to the nuclear tests of the early 1960s-a minimum not found in this analysis. The observed variation in global total ozone has been compared with the variation predicted by one of the models up to the sunspot maximum in 1990, and the agreement is shown to be good through the northern summer of 1988 if the impact of the QBO on global total ozone is taken into account. On the basis of the present analysis, there has been a 1.0 ± 0.9% decrease in global total ozone between solar cycles 20 and 21, a decrease 70% larger than that indicated by the three stratospheric models.

Characteristics of sludge reduction in an integrated pretreatment and aerobic digestion process.

PubMed

Hwang, S; Jang, H; Lee, M; Song, J; Kim, S

2006-01-01

In this study, integrated pretreatments and aerobic digestion processes were investigated in order to provide a feasible alternative that can achieve effective sludge reduction. An ozone treatment in the presence of ionic manganese, a catalyst, increased the sludge reduction ratio three times higher than that of a single ozonation, presumably due to an increase in OH radical production. The ozone treatment yielded the effective sludge reduction ratio with an increasing ozone dosage, and an effective dosage of the catalyst was found to be 4 mg-Mn/g-TS. When a mechanical pretreatment and an ozone/catalyst were applied in a series, the integrated process, even at a half mechanical intensity and a half level of ozone dosage, showed higher and faster sludge reduction than each single process did. In addition, the integrated pretreatment process showed the highest dewaterability of the treated sludges. A ratio of sludge cake generation, which was newly introduced to quantify overall performance of sludge treatment processes, showed that the integrated pretreatment followed by the aerobic digestion yielded approximately a half of the sludge cake volume compared to the single aerobic digestion. Therefore, the integrated pretreatment can be a feasible method for the effective reduction of total suspended solid and the final volume.

Molecular and Immunological Characterization of Ragweed (Ambrosia artemisiifolia L.) Pollen after Exposure of the Plants to Elevated Ozone over a Whole Growing Season

PubMed Central

Kanter, Ulrike; Heller, Werner; Durner, Jörg; Winkler, J. Barbro; Engel, Marion; Behrendt, Heidrun; Holzinger, Andreas; Braun, Paula; Hauser, Michael; Ferreira, Fatima; Mayer, Klaus; Pfeifer, Matthias; Ernst, Dieter

2013-01-01

Climate change and air pollution, including ozone is known to affect plants and might also influence the ragweed pollen, known to carry strong allergens. We compared the transcriptome of ragweed pollen produced under ambient and elevated ozone by 454-sequencing. An enzyme-linked immunosorbent assay (ELISA) was carried out for the major ragweed allergen Amb a 1. Pollen surface was examined by scanning electron microscopy and attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR), and phenolics were analysed by high-performance liquid chromatography. Elevated ozone had no influence on the pollen size, shape, surface structure or amount of phenolics. ATR-FTIR indicated increased pectin-like material in the exine. Transcriptomic analyses showed changes in expressed-sequence tags (ESTs), including allergens. However, ELISA indicated no significantly increased amounts of Amb a 1 under elevated ozone concentrations. The data highlight a direct influence of ozone on the exine components and transcript level of allergens. As the total protein amount of Amb a 1 was not altered, a direct correlation to an increased risk to human health could not be derived. Additional, the 454-sequencing contributes to the identification of stress-related transcripts in mature pollen that could be grouped into distinct gene ontology terms. PMID:23637846

Preexposure to ozone blocks the antigen-induced late asthmatic response of the canine peripheral airways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turner, C.R.; Kleeberger, S.R.; Spannhake, E.W.

1989-01-01

The influence of exposure of the airways to ozone on acute allergic responsiveness has been investigated in several species. Little is known, however, about the effect of this environmental pollutant on the late asthmatic response (LAR) in animals in which it is exhibited. The purpose of this study was to evaluate this effect in the canine peripheral airways and to assess the potential role of mast cells in modulating the effect. A series of experiments on seven mongrel dogs demonstrated that the numbers of mast cells at the base of the epithelial region of small subsegmental airways exposed to 1more » ppm ozone for 5 min were significantly (p less than .01) increased 3 h following exposure compared to air exposed or nonexposed control airways. In a second series of experiments performed on eight additional mongrel dogs with inherent sensitivity to Ascaris suum antigen, antigen aerosol was administered to the sublobar segment 3 h following ozone preexposure when mast cell numbers were presumed to be increased. These experiments were performed to determine whether ozone preexposure could enhance the late-phase response to antigen by virtue of acutely increasing the number of mast cells available to bind the antigen. Four of the eight dogs tested displayed a late-phase response to antigen following air-sham preexposure. In these four dogs, simultaneous ozone preexposure of a contralateral lobe completely blocked the late-phase response to antigen. These results indicate that the consequences of a single exposure to ozone persist beyond its effects on acute antigen-induced bronchoconstriction and extend to the complex processes involved with the late response. This attenuating effect of ozone is seen under conditions where mast-cell numbers in the airways are increased above baseline levels.« less

Research on the influence of ozone dissolved in the fuel-water emulsion on the parameters of the CI engine

NASA Astrophysics Data System (ADS)

Wojs, M. K.; Orliński, P.; Kamela, W.; Kruczyński, P.

2016-09-01

The article presents the results of empirical research on the impact of ozone dissolved in fuel-water emulsion on combustion process and concentration of toxic substances in CI engine. The effect of ozone presence in the emulsion and its influence on main engine characteristics (power, torque, fuel consumption) and selected parameters that characterize combustion process (levels of pressures and temperatures in combustion chamber, period of combustion delay, heat release rate, fuel burnt rate) is shown. The change in concentration of toxic components in exhausts gases when engine is fueled with ozonized emulsion was also identified. The empirical research and their analysis showed significant differences in the combustion process when fuel-water emulsion containing ozone was used. These differences include: increased power and efficiency of the engine that are accompanied by reduction in time of combustion delay and beneficial effects of ozone on HC, PM, CO and NOX emissions.

Ozone Bioindicator Gardens: an Educational Tool to Raise Awareness about Environmental Pollution and its Effects on Living Systems

NASA Astrophysics Data System (ADS)

Lapina, K.; Lombardozzi, D.

2014-12-01

High concentrations of ground-level ozone cause health problems in humans and a number of negative effects on plants, from reduced yield for major agricultural crops to reduced amounts of carbon stored in trees. The Denver Metro/Colorado Front Range is exceeding the National Ambient Air Quality Standard for ozone on a regular basis in summer and the efforts to reduce the ozone levels are hampered by the presence of diverse pollution sources and complex meteorology in the region. To raise public awareness of air quality in the Colorado Front Range and to educate all age groups about ground-level ozone, two ozone bioindicator gardens were planted in Boulder in Spring 2014. The gardens contain ozone-sensitive plants that develop a characteristic ozone injury when exposed to high levels of ozone. The ozone gardens are providing the general public with a real-life demonstration of the negative effects of ozone pollution through observable plant damage. Additionally, the gardens are useful in teaching students how to collect and analyze real-world scientific data.

Decadal Changes in Ozone and Emissions in Central California and Current Issues

NASA Astrophysics Data System (ADS)

Tanrikulu, S.; Beaver, S.; Soong, S.; Tran, C.; Cordova, J.; Palazoglu, A.

2011-12-01

The relationships among ozone, emissions, and meteorology are very complex in central California, and must be well studied and understood in order to facilitate better air quality planning. Factors significantly impacting changes in emissions such as economic and population growth, and adopted emission controls make the matter even more complex. Here we review the history of ozone pollution in central California since the 1970s to plan for the future. Since the 1970s, changes in emissions have been accompanied by likewise dramatic changes in region-to-region differences in air quality. We focus on the coastal San Francisco Bay Area (SFBA) and the inland San Joaquin Valley (SJV). In the 1970s, the SFBA population was approaching 5 million people while the considerably larger and more rural SJV population remained below 2 million. The SFBA population was mostly confined to coastal locations. Peak ozone levels occurred mostly around the population centers and especially over the Bay itself. Hourly average ozone levels routinely approached 160 ppb. These high ozone levels promoted regulations under which SFBA emissions were continuously reduced through the present. By the 1990s, SFBA emissions had been reduced considerably despite the region's population growing to around 6 million. Relative to the 1970s, in 1990s the SFBA had lower peak ozone levels that were shifted to inland locations where much of the population growth was occurring. The SFBA still exceeded the federal 1-hour standard. A rapidly changing economic landscape in the 1970s promoted vast changes in the central California population distribution. In the SJV, the OPEC oil crisis promoted significant development of petroleum resources. Meanwhile, family farms were quickly being replaced with commercial-scale farming operations. The SJV population rapidly expanded to around 3 million people by the early 1990s. During this time, SJV emissions increased considerably, largely from increases in mobile source activities. The previously sparsely populated SJV had quickly developed an even more severe ozone problem than previous years. From 1990 to 2010, the SFBA population expanded to inland locations and then even further into the sheltered SJV. SFBA emissions for ROG and NOx were decreased around 40% and 15%, respectively during this period. High ozone levels became rather infrequent for coastal SFBA locations. During the same period, the SJV population continued to expand rapidly while emissions decreased, especially for ROG. Peak ozone levels remained around 100 ppb and shifted to locations downwind of Fresno and Bakersfield. Central California has experienced perhaps the most dramatic population growth and shifts in the United States during the contemporary economic era. These changes in population have led to some of the most difficult air quality management problems faced by regulators in the United States. Lessons learned from central California highlight the potential benefits of acting early and also the necessity for a long-term, flexible approach using sustained regulations to accompany population changes.

Impact of biogenic very short-lived bromine on the Antarctic ozone hole during the 21st century

NASA Astrophysics Data System (ADS)

Fernandez, Rafael P.; Kinnison, Douglas E.; Lamarque, Jean-Francois; Tilmes, Simone; Saiz-Lopez, Alfonso

2017-02-01

Active bromine released from the photochemical decomposition of biogenic very short-lived bromocarbons (VSLBr) enhances stratospheric ozone depletion. Based on a dual set of 1960-2100 coupled chemistry-climate simulations (i.e. with and without VSLBr), we show that the maximum Antarctic ozone hole depletion increases by up to 14 % when natural VSLBr are considered, which is in better agreement with ozone observations. The impact of the additional 5 pptv VSLBr on Antarctic ozone is most evident in the periphery of the ozone hole, producing an expansion of the ozone hole area of ˜ 5 million km2, which is equivalent in magnitude to the recently estimated Antarctic ozone healing due to the implementation of the Montreal Protocol. We find that the inclusion of VSLBr in CAM-Chem (Community Atmosphere Model with Chemistry, version 4.0) does not introduce a significant delay of the modelled ozone return date to 1980 October levels, but instead affects the depth and duration of the simulated ozone hole. Our analysis further shows that total bromine-catalysed ozone destruction in the lower stratosphere surpasses that of chlorine by the year 2070 and indicates that natural VSLBr chemistry would dominate Antarctic ozone seasonality before the end of the 21st century. This work suggests a large influence of biogenic bromine on the future Antarctic ozone layer.

CONTRIBUTION TO INDOOR OZONE LEVELS OF AN OZONE GENERATOR

EPA Science Inventory

This report gives results of a study of a commonly used commercially available ozone generator, undertaken to determine its impact on indoor ozone levels. xperiment were conducted in a typical mechanically ventilated office and in a test house. he generated ozone and the in-room ...

Sensitivities of NOx transformation and the effects on surface ozone and nitrate

NASA Astrophysics Data System (ADS)

Lei, H.; Wang, J. X. L.

2014-02-01

As precursors to tropospheric ozone and nitrate, nitrogen oxide (NOx) in the present atmosphere and its transformation in response to emission and climate perturbations are studied by using the CAM-Chem model and air quality measurements from the National Emissions Inventory (NEI), Clean Air Status and Trends Network (CASTNET), and Environmental Protection Agency Air Quality System (EPA AQS). It is found that NOx transformations in present atmospheric conditions show different sensitivities over industrial and non-industrial regions. As a result, the surface ozone and nitrate formations can be divided into several regimes associated with the dominant emission types and relative levels of NOx and volatile organic compounds (VOC). Ozone production in industrial regions (the main NOx emission source areas) increases in warmer conditions and slightly decreases following an increase in NOx emissions due to NOx titration, which is opposite to the response in non-industrial regions. The ozone decrease following a temperature increase in non-industrial regions indicates that ozone production in regions that lack NOx emission sources may be sensitive to NOx transformation in remote source regions. The increase in NO2 from NOx titration over industrial regions results in an increase rate of total nitrate that remains higher than the increase rate of NOx emissions. The presented findings indicate that a change in the ozone concentration is more directly affected by changes in climate and precursor emissions, while a change in the nitrate concentration is affected by local ozone production types and their seasonal transfer. The sensitivity to temperature perturbations shows that a warmer climate accelerates the decomposition of odd nitrogen (NOy) during the night. As a result, the transformation rate of NOx to nitrate decreases. Examinations of the historical emissions and air quality records of a typical NOx-limited area, such as Atlanta and a VOC-limited area, such as Los Angeles further confirm the conclusions drawn from the modeling experiments.

Ozone fumigation under dark/light conditions of Norway Spruce (Picea Abies) and Scots Pine (Pinus Sylvestris)

NASA Astrophysics Data System (ADS)

Canaval, Eva; Jud, Werner; Hansel, Armin

2015-04-01

Norway Spruce (Picea abies) and Scots Pine (Pinus sylvestris) represent dominating tree species in the northern hemisphere. Thus, the understanding of their ozone sensitivity in the light of the expected increasing ozone levels in the future is of great importance. In our experiments we investigated the emissions of volatile organic compounds (VOCs) of 3-4 year old Norway Spruce and Scots Pine seedlings under ozone fumigation (50-150 ppbv) and dark/light conditions. For the experiments the plants were placed in a setup with inert materials including a glass cuvette equipped with a turbulent air inlet and sensors for monitoring a large range of meteorological parameters. Typical conditions were 20-25°C and a relative humidity of 70-90 % for both plant species. A fast gas exchange rate was used to minimize reactions of ozone in the gas phase. A Switchable-Reagent-Ion-Time-of-Flight-MS (SRI-ToF-MS) was used to analyze the VOCs at the cuvette outlet in real-time during changing ozone and light levels. The use of H3O+ and NO+ as reagent ions allows the separation of certain isomers (e.g. aldehydes and ketones) due to different reaction pathways depending on the functional groups of the molecules. Within the Picea abies experiments the ozone loss, defined as the difference of the ozone concentration between cuvette inlet and outlet, remained nearly constant at the transition from dark to light. This indicates that a major part of the supplied ozone is depleted non-stomatally. In contrast the ozone loss increased by 50 % at the transition from dark to light conditions within Pinus sylvestris experiments. In this case the stomata represent the dominant loss channel. Since maximally 0.1% of the ozone loss could be explained by gas phase reactions with monoterpenes and sesquiterpenes, we suggest that ozone reactions on the surface of Picea abies represent the major sink in this case and lead to an light-independent ozone loss. This is supported by the fact that we detected a broad range of unidentified oxygenated ozonolysis products and their fragments, whose amount exceed by far the detected loss of BVOCs under ozone exposure. However, the observed products are not attributable to neither green leaf volatiles nor to other known volatile precursors. Furthermore Picea abies emits a smaller amount of ozone induced green leaf volatiles than Pinus sylvestris. Based on this results we can explain the higher ozone tolerance of Picea abies, which has been observed before. A likely reason for the differences in stomatal and surface ozone loss on the investigated plants are differences in the amount and kind of unsaturated semi-volatile compounds on the needle surface.

Stratospheric ozone measurements at Arosa (Switzerland): history and scientific relevance

NASA Astrophysics Data System (ADS)

Staehelin, Johannes; Viatte, Pierre; Stübi, Rene; Tummon, Fiona; Peter, Thomas

2018-05-01

Climatic Observatory (LKO) in Arosa (Switzerland), marking the beginning of the world's longest series of total (or column) ozone measurements. They were driven by the recognition that atmospheric ozone is important for human health, as well as by scientific curiosity about what was, at the time, an ill characterised atmospheric trace gas. From around the mid-1950s to the beginning of the 1970s studies of high atmosphere circulation patterns that could improve weather forecasting was justification for studying stratospheric ozone. In the mid-1970s, a paradigm shift occurred when it became clear that the damaging effects of anthropogenic ozone-depleting substances (ODSs), such as long-lived chlorofluorocarbons, needed to be documented. This justified continuing the ground-based measurements of stratospheric ozone. Levels of ODSs peaked around the mid-1990s as a result of a global environmental policy to protect the ozone layer, implemented through the 1987 Montreal Protocol and its subsequent amendments and adjustments. Consequently, chemical destruction of stratospheric ozone started to slow around the mid-1990s. To some extent, this raises the question as to whether continued ozone observation is indeed necessary. In the last decade there has been a tendency to reduce the costs associated with making ozone measurements globally including at Arosa. However, the large natural variability in ozone on diurnal, seasonal, and interannual scales complicates the capacity for demonstrating the success of the Montreal Protocol. Chemistry-climate models also predict a super-recovery of the ozone layer at mid-latitudes in the second half of this century, i.e. an increase of ozone concentrations beyond pre-1970 levels, as a consequence of ongoing climate change. These factors, and identifying potentially unexpected stratospheric responses to climate change, support the continued need to document stratospheric ozone changes. This is particularly valuable at the Arosa site, due to the unique length of the observational record. This paper presents the evolution of the ozone layer, the history of international ozone research, and discusses the justification for the measurements in the past, present and into future.

Satellite Observations and Chemistry Climate Models - A Meandering Path Towards Better Predictions

NASA Technical Reports Server (NTRS)

Douglass, Anne R.

2011-01-01

Knowledge of the chemical and dynamical processes that control the stratospheric ozone layer has grown rapidly since the 1970s, when ideas that depletion of the ozone layer due to human activity were put forth. The concept of ozone depletion due to anthropogenic chlorine increase is simple; quantification of the effect is much more difficult. The future of stratospheric ozone is complicated because ozone is expected to increase for two reasons: the slow decrease in anthropogenic chlorine due to the Montreal Protocol and its amendments and stratospheric cooling caused by increases in carbon dioxide and other greenhouse gases. Prediction of future ozone levels requires three-dimensional models that represent physical, photochemical and radiative processes, i.e., chemistry climate models (CCMs). While laboratory kinetic and photochemical data are necessary inputs for a CCM, atmospheric measurements are needed both to reveal physical and chemical processes and for comparison with simulations to test the conceptual model that CCMs represent. Global measurements are available from various satellites including but not limited to the LIMS and TOMS instruments on Nimbus 7 (1979 - 1993), and various instruments on the Upper Atmosphere Research Satellite (1991 - 2005), Envisat (2002 - ongoing), Sci-Sat (2003 - ongoing) and Aura (2004 - ongoing). Every successful satellite instrument requires a physical concept for the measurement, knowledge of physical chemical properties of the molecules to be measured, and stellar engineering to design an instrument that will survive launch and operate for years with no opportunity for repair but providing enough information that trend information can be separated from any instrument change. The on-going challenge is to use observations to decrease uncertainty in prediction. This talk will focus on two applications. The first considers transport diagnostics and implications for prediction of the eventual demise of the Antarctic ozone hole. The second focuses on the upper stratosphere, where ozone is predicted to increase both due to chlorine decrease and due to temperature decrease expected as a result of increased concentrations Of CO2 and other greenhouse gases. Both applications show how diagnostics developed from global observations are being used to explain why the ozone response varies among CCM predictions for stratospheric ozone in the 21st century.

THE EMERGING RELATIONSHIP BETWEEN GROUND LEVEL OZONE AND LANDSCAPE CHARACTERISTICS

EPA Science Inventory

One of the most serious environmental health problems facing our society is that of poor air quality caused primarily by the formation of ground level ozone. Although natural ozone is beneficial in the upper atmosphere as a filter for ultraviolet radiation, ground- level ozone is...

Innate Lymphoid Cells Mediate Pulmonary Eosinophilic Inflammation, Airway Mucous Cell Metaplasia, and Type 2 Immunity in Mice Exposed to Ozone.

PubMed

Kumagai, Kazuyoshi; Lewandowski, Ryan P; Jackson-Humbles, Daven N; Buglak, Nicholas; Li, Ning; White, Kaylin; Van Dyken, Steven J; Wagner, James G; Harkema, Jack R

2017-08-01

Exposure to elevated levels of ambient ozone in photochemical smog is associated with eosinophilic airway inflammation and nonatopic asthma in children. In the present study, we determined the role of innate lymphoid cells (ILCs) in the pathogenesis of ozone-induced nonatopic asthma by using lymphoid cell-sufficient C57BL/6 mice, ILC-sufficient Rag2 -/- mice (devoid of T and B cells), and ILC-deficient Rag2 -/- Il2rg -/- mice (depleted of all lymphoid cells including ILCs). Mice were exposed to 0 or 0.8 parts per million ozone for 1 day or 9 consecutive weekdays (4 hr/day). A single exposure to ozone caused neutrophilic inflammation, airway epithelial injury, and reparative DNA synthesis in all strains of mice, irrespective of the presence or absence of ILCs. In contrast, 9-day exposures induced eosinophilic inflammation and mucous cell metaplasia only in the lungs of ILC-sufficient mice. Repeated ozone exposures also elicited increased messenger RNA expression of transcripts associated with type 2 immunity and airway mucus production in ILC-sufficient mice. ILC-deficient mice repeatedly exposed to ozone had no pulmonary pathology or increased gene expression related to type 2 immunity. These results suggest a new paradigm for the biologic mechanisms underlying the development of a phenotype of childhood nonatopic asthma that has been linked to ambient ozone exposures.

A Lagrangian analysis of the impact of transport and transformation on the ozone stratification observed in the free troposphere during the ESCOMPTE campaign

NASA Astrophysics Data System (ADS)

Colette, A.; Ancellet, G.; Menut, L.; Arnold, S. R.

2006-03-01

The ozone variability observed by tropospheric ozone lidars during the ESCOMPTE campaign is analyzed by means of a hybrid-Lagrangian modeling study. Transport processes responsible for the formation of ozone-rich layers are identified using a semi-Lagrangian analysis of mesoscale simulations to identify the planetary boundary layer (PBL) footprint in the free troposphere. High ozone concentrations are related to polluted air masses exported from the Iberian PBL. The chemical composition of air masses coming from the PBL and transported in the free troposphere is evaluated using a Lagrangian chemistry model. The initial concentrations are provided by a model of chemistry and transport. Different scenarios are tested for the initial conditions and for the impact of mixing with background air in order to perform a quantitative comparison with the lidar observations. For this meteorological situation, the characteristic mixing time is of the order of 2 to 5 days depending on the initial conditions. Ozone is produced in the free troposphere within most air masses exported from the Iberian PBL at an average rate of 0.2 ppbv h-1, with a maximum ozone production of 0.4 ppbv h-1. Transport processes from the PBL are responsible for an increase of 13.3 ppbv of ozone concentrations in the free troposphere compared to background levels; about 45% of this increase is attributed to in situ production during the transport rather than direct export of ozone.

A Lagrangian analysis of the impact of transport and transformation on the ozone stratification observed in the free troposphere during the ESCOMPTE campaign

NASA Astrophysics Data System (ADS)

Colette, A.; Ancellet, G.; Menut, L.; Arnold, S. R.

2006-08-01

The ozone variability observed by tropospheric ozone lidars during the ESCOMPTE campaign is analyzed by means of a hybrid-Lagrangian modeling study. Transport processes responsible for the formation of ozone-rich layers are identified using a semi-Lagrangian analysis of mesoscale simulations to identify the planetary boundary layer (PBL) footprint in the free troposphere. High ozone concentrations are related to polluted air masses exported from the Iberian PBL. The chemical composition of air masses coming from the PBL and transported in the free troposphere is evaluated using a Lagrangian chemistry model. The initial concentrations are provided by a model of chemistry and transport. Different scenarios are tested for the initial conditions and for the impact of mixing with background air in order to perform a quantitative comparison with the lidar observations. For this meteorological situation, the characteristic mixing time is of the order of 2 to 6 days depending on the initial conditions. Ozone is produced in the free troposphere within most air masses exported from the Iberian PBL at an average rate of 0.2 ppbv h-1, with a maximum ozone production of 0.4 ppbv h-1. Transport processes from the PBL are responsible for an increase of 13.3 ppbv of ozone concentrations in the free troposphere compared to background levels; about 45% of this increase is attributed to in situ production during the transport rather than direct export of ozone.

Ozone, Tropospheric

NASA Technical Reports Server (NTRS)

Fishman, Jack

1995-01-01

In the early part of the 20th century, ground-based and balloon-borne measurements discovered that most of atmosphere's ozone is located in the stratosphere with highest concentrations located between 15 and 30 km (9,3 and 18.6 miles). For a long time, it was believed that tropospheric ozone originated from the stratosphere and that most of it was destroyed by contact with the earth's surface. Ozone, O3, was known to be produced by the photo-dissociation of molecular oxygen, O2, a process that can only occur at wavelengths shorter than 242 nm. Because such short-wave-length radiation is present only in the stratosphere, no tropospheric ozone production is possible by this mechanism. In the 1940s, however, it became obvious that production of ozone was also taking place in the troposphere. The overall reaction mechanism was eventually identified by Arie Haagen-Smit of the California Institute of Technology, in highly polluted southern California. The copious emissions from the numerous cars driven there as a result of the mass migration to Los Angeles after World War 2 created the new unpleasant phenomenon of photochemical smog, the primary component of which is ozone. These high levels of ozone were injuring vegetable crops, causing women's nylons to run, and generating increasing respiratory and eye-irritation problems for the populace. Our knowledge of tropospheric ozone increased dramatically in the early 1950s as monitoring stations and search centers were established throughout southern California to see what could be done to combat this threat to human health and the environment.

Ozone-induced airway hyperresponsiveness in patients with asthma: role of neutrophil-derived serine proteinases.

PubMed

Hiltermann, T J; Peters, E A; Alberts, B; Kwikkers, K; Borggreven, P A; Hiemstra, P S; Dijkman, J H; van Bree, L A; Stolk, J

1998-04-01

Proteinase inhibitors may be of potential therapeutic value in the treatment of respiratory diseases such as chronic obstructive pulmonary disease (COPD) or asthma. Our aim was to study the role of neutrophils, and neutrophil-derived serine proteinases in an acute model in patients with asthma. Exposure to ozone induces an acute neutrophilic inflammatory reaction accompanied by an increase in airway hyperresponsiveness. It is thought that these two effects of ozone are linked, and that neutrophil-derived serine proteinases (i.e. elastase) may play a role in the ozone-induced airway hyperresponsiveness. Therefore, we examined the effect of recombinant antileukoprotease (rALP), one of the major serine proteinase inhibitors in the lung, on ozone-induced changes in airway hyperresponsiveness in this model. We observed that 16 h after exposure to ozone, airway hyperresponsiveness to methacholine was increased both following placebo and rALP treatment. There was no significant difference between placebo and rALP treatment (change in area under the dose-response curve to methacholine: 117.3+/-59.0 vs 193.6+/-59.6 % fall x DD; p=.12). Moreover, the immediate decrease in FEV1 after ozone exposure was not significantly different between the two groups (placebo: -29.6+/-6.7%; rALP: -20.9+/-3.8%; p=.11). In addition, no significant differences were observed in plasma levels of fibrinogen degradation products generated by neutrophil serine proteinases before and after exposure to ozone. We conclude that neutrophil-derived serine proteinases are not important mediators for ozone-induced hyperresponsiveness.

Effect of Acute Ozone Induced Airway Inflammation on Human Sympathetic Nerve Traffic: A Randomized, Placebo Controlled, Crossover Study

PubMed Central

Tank, Jens; Biller, Heike; Heusser, Karsten; Holz, Olaf; Diedrich, André; Framke, Theodor; Koch, Armin; Grosshennig, Anika; Koch, Wolfgang; Krug, Norbert; Jordan, Jens; Hohlfeld, Jens M.

2011-01-01

Background Ozone concentrations in ambient air are related to cardiopulmonary perturbations in the aging population. Increased central sympathetic nerve activity induced by local airway inflammation may be one possible mechanism. Methodology/Principal Findings To elucidate this issue further, we performed a randomized, double-blind, cross-over study, including 14 healthy subjects (3 females, age 22–47 years), who underwent a 3 h exposure with intermittent exercise to either ozone (250 ppb) or clean air. Induced sputum was collected 3 h after exposure. Nineteen to 22 hours after exposure, we recorded ECG, finger blood pressure, brachial blood pressure, respiration, cardiac output, and muscle sympathetic nerve activity (MSNA) at rest, during deep breathing, maximum-inspiratory breath hold, and a Valsalva maneuver. While the ozone exposure induced the expected airway inflammation, as indicated by a significant increase in sputum neutrophils, we did not detect a significant estimated treatment effect adjusted for period on cardiovascular measurements. Resting heart rate (clean air: 59±2, ozone 60±2 bpm), blood pressure (clean air: 121±3/71±2 mmHg; ozone: 121±2/71±2 mmHg), cardiac output (clean air: 7.42±0.29 mmHg; ozone: 7.98±0.60 l/min), and plasma norepinephrine levels (clean air: 213±21 pg/ml; ozone: 202±16 pg/ml), were similar on both study days. No difference of resting MSNA was observed between ozone and air exposure (air: 23±2, ozone: 23±2 bursts/min). Maximum MSNA obtained at the end of apnea (air: 44±4, ozone: 48±4 bursts/min) and during the phase II of the Valsalva maneuver (air: 64±5, ozone: 57±6 bursts/min) was similar. Conclusions/Significance Our study suggests that acute ozone-induced airway inflammation does not increase resting sympathetic nerve traffic in healthy subjects, an observation that is relevant for environmental health. However, we can not exclude that chronic airway inflammation may contribute to sympathetic activation. PMID:21494635

Seasonal ozone levels and control by seasonal meteorology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pagnotti, V.

1990-02-01

Meteorological data, particularly 850-MB level temperatures, for Fort Totten, New York (1980) and Atlantic City, New Jersey (1981-1988) were examined for any relationship to seasonal ozone levels. Other radiosonde stations in the Northeast were utilized for 1983 and 1986, years of widely differing ozone levels. Statistics for selected parameters and years are presented. Emphasis is placed on recurring warm temperature regimes in high ozone years. Successive occurrences or episodes of high temperatures characterize seasonally high ozone years. Seasonally persistent high temperatures are related to seasonally chronic high ozone. An example is presented relating the broad-scale climatologically anomalous pattern of highmore » temperatures to anomalous circulation patterns at the 700-MB level.« less

Maternal diesel inhalation increases airway hyperreactivity in ozone-exposed offspring.

PubMed

Auten, Richard L; Gilmour, M Ian; Krantz, Q Todd; Potts, Erin N; Mason, S Nicholas; Foster, W Michael

2012-04-01

Air pollutant exposure is linked with childhood asthma incidence and exacerbations, and maternal exposure to airborne pollutants during pregnancy increases airway hyperreactivity (AHR) in offspring. To determine if exposure to diesel exhaust (DE) during pregnancy worsened postnatal ozone-induced AHR, timed pregnant C57BL/6 mice were exposed to DE (0.5 or 2.0 mg/m(3)) 4 hours daily from Gestation Day 9-17, or received twice-weekly oropharyngeal aspirations of the collected DE particles (DEPs). Placentas and fetal lungs were harvested on Gestation Day 18 for cytokine analysis. In other litters, pups born to dams exposed to air or DE, or to dams treated with aspirated diesel particles, were exposed to filtered air or 1 ppm ozone beginning the day after birth, for 3 hours per day, 3 days per week for 4 weeks. Additional pups were monitored after a 4-week recovery period. Diesel inhalation or aspiration during pregnancy increased levels of placental and fetal lung cytokines. There were no significant effects on airway leukocytes, but prenatal diesel augmented ozone-induced elevations of bronchoalveolar lavage cytokines at 4 weeks. Mice born to the high-concentration diesel-exposed dams had worse ozone-induced AHR, which persisted in the 4-week recovery animals. Prenatal diesel exposure combined with postnatal ozone exposure also worsened secondary alveolar crest development. We conclude that maternal inhalation of DE in pregnancy provokes a fetal inflammatory response that, combined with postnatal ozone exposure, impairs alveolar development, and causes a more severe and long-lasting AHR to ozone exposure.

Stratospheric ozone changes under solar geoengineering: implications for UV exposure and air quality

NASA Astrophysics Data System (ADS)

Nowack, Peer Johannes; Abraham, Nathan Luke; Braesicke, Peter; Pyle, John Adrian

2016-03-01

Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term solar radiation management (SRM). Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere-ocean coupled climate model, we include atmospheric composition feedbacks for this experiment. While the SRM scheme considered here could offset greenhouse gas induced global mean surface warming, it leads to important changes in atmospheric composition. We find large stratospheric ozone increases that induce significant reductions in surface UV-B irradiance, which would have implications for vitamin D production. In addition, the higher stratospheric ozone levels lead to decreased ozone photolysis in the troposphere. In combination with lower atmospheric specific humidity under SRM, this results in overall surface ozone concentration increases in the idealized G1 experiment. Both UV-B and surface ozone changes are important for human health. We therefore highlight that both stratospheric and tropospheric ozone changes must be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.

Ozone and increased nitrogen supply effects on the yield and nutritive quality of Trifolium subterraneum

NASA Astrophysics Data System (ADS)

Sanz, J.; Muntifering, R. B.; Bermejo, V.; Gimeno, B. S.; Elvira, S.

The influence of ambient ozone (O 3) concentrations and nitrogen (N) fertilization, singly and in combination, on the growth and nutritive quality of Trifolium subterraneum was assessed. This is an important O 3-sensitive species of great pastoral value in Mediterranean areas. Plant material was enclosed in open-top chambers (OTCs). Three O 3 levels were established: Filtered air with O 3 concentrations below 15 ppb (CFA), non-filtered air with O 3 concentrations in the range of ambient levels (NFA), and non-filtered air supplemented with 40 ppb O 3 over ambient levels (NFA+). Similarly, three N levels were defined: 5, 15 and 30 kg ha -1. The increase in O 3 exposure induced a reduction of the clover aerial green biomass and an increase of senescent biomass. Ozone effects were more adverse in the root system, inducing an impairment of the aerial/subterranean biomass ratio. Compared with the CFA treatment, nutritive quality of aerial biomass was 10 and 20% lower for NFA and NFA+ treatments, respectively, due to increased concentrations of acid detergent fiber, neutral detergent fiber and lignin. The latter effect appears to be related to senescence acceleration. The increment in N supplementation enhanced the increase of ADF concentrations in those plants simultaneously exposed to ambient and above-ambient O 3 concentrations, and reduced the incremental rate of foliar senescence induced by the pollutant.

Ambient ozone effects on gas exchange and total non-structural carbohydrate levels in cutleaf coneflower (Rudbeckia laciniata L.) growing in Great Smoky Mountains National Park

USDA-ARS?s Scientific Manuscript database

Ozone-sensitive and -tolerant individuals of the perennial herbaceous cutleaf coneflower (Rudbeckia laciniata L.) were compared for their gas exchange characteristics and total non-structural carbohydrates in the Great Smoky Mountains National Park USA. Net photosynthesis decreased with increased f...

The impact of recirculation, ventilation and filters on secondary organic aerosols generated by indoor chemistry

NASA Astrophysics Data System (ADS)

Fadeyi, M. O.; Weschler, C. J.; Tham, K. W.

This study examined the impact of recirculation rates (7 and 14 h -1), ventilation rates (1 and 2 h -1), and filtration on secondary organic aerosols (SOAs) generated by ozone of outdoor origin reacting with limonene of indoor origin. Experiments were conducted within a recirculating air handling system that serviced an unoccupied, 236 m 3 environmental chamber configured to simulate an office; either no filter, a new filter or a used filter was located downstream of where outdoor air mixed with return air. For otherwise comparable conditions, the SOA number and mass concentrations at a recirculation rate of 14 h -1 were significantly smaller than at a recirculation rate of 7 h -1. This was due primarily to lower ozone concentrations, resulting from increased surface removal, at the higher recirculation rate. Increased ventilation increased outdoor-to-indoor transport of ozone, but this was more than offset by the increased dilution of SOA derived from ozone-initiated chemistry. The presence of a particle filter (new or used) strikingly lowered SOA number and mass concentrations compared with conditions when no filter was present. Even though the particle filter in this study had only 35% single-pass removal efficiency for 100 nm particles, filtration efficiency was greatly amplified by recirculation. SOA particle levels were reduced to an even greater extent when an activated carbon filter was in the system, due to ozone removal by the carbon filter. These findings improve our understanding of the influence of commonly employed energy saving procedures on occupant exposures to ozone and ozone-derived SOA.

Systemic metabolic derangement, pulmonary effects, and insulin insufficiency following subchronic ozone exposure in rats.

PubMed

Miller, Desinia B; Snow, Samantha J; Henriquez, Andres; Schladweiler, Mette C; Ledbetter, Allen D; Richards, Judy E; Andrews, Debora L; Kodavanti, Urmila P

2016-09-01

Acute ozone exposure induces a classical stress response with elevated circulating stress hormones along with changes in glucose, protein and lipid metabolism in rats, with similar alterations in ozone-exposed humans. These stress-mediated changes over time have been linked to insulin resistance. We hypothesized that acute ozone-induced stress response and metabolic impairment would persist during subchronic episodic exposure and induce peripheral insulin resistance. Male Wistar Kyoto rats were exposed to air or 0.25ppm or 1.00ppm ozone, 5h/day, 3 consecutive days/week (wk) for 13wks. Pulmonary, metabolic, insulin signaling and stress endpoints were determined immediately after 13wk or following a 1wk recovery period (13wk+1wk recovery). We show that episodic ozone exposure is associated with persistent pulmonary injury and inflammation, fasting hyperglycemia, glucose intolerance, as well as, elevated circulating adrenaline and cholesterol when measured at 13wk, however, these responses were largely reversible following a 1wk recovery. Moreover, the increases noted acutely after ozone exposure in non-esterified fatty acids and branched chain amino acid levels were not apparent following a subchronic exposure. Neither peripheral or tissue specific insulin resistance nor increased hepatic gluconeogenesis were present after subchronic ozone exposure. Instead, long-term ozone exposure lowered circulating insulin and severely impaired glucose-stimulated beta-cell insulin secretion. Thus, our findings in young-adult rats provide potential insights into epidemiological studies that show a positive association between ozone exposures and type 1 diabetes. Ozone-induced beta-cell dysfunction may secondarily contribute to other tissue-specific metabolic alterations following chronic exposure due to impaired regulation of glucose, lipid, and protein metabolism. Published by Elsevier Inc.

Systemic metabolic derangement, pulmonary effects, and insulin insufficiency following subchronic ozone exposure in rats☆,☆☆

PubMed Central

Miller, Desinia B.; Snow, Samantha J.; Henriquez, Andres; Schladweiler, Mette C.; Ledbetter, Allen D.; Richards, Judy E.; Andrews, Debora L.; Kodavanti, Urmila P.

2017-01-01

Acute ozone exposure induces a classical stress response with elevated circulating stress hormones along with changes in glucose, protein and lipid metabolism in rats, with similar alterations in ozone-exposed humans. These stress-mediated changes over time have been linked to insulin resistance. We hypothesized that acute ozone-induced stress response and metabolic impairment would persist during subchronic episodic exposure and induce peripheral insulin resistance. Male Wistar Kyoto rats were exposed to air or 0.25 ppm or 1.00 ppm ozone, 5 h/day, 3 consecutive days/week (wk) for 13 wks. Pulmonary, metabolic, insulin signaling and stress endpoints were determined immediately after 13 wk or following a 1 wk recovery period (13 wk + 1 wk recovery). We show that episodic ozone exposure is associated with persistent pulmonary injury and inflammation, fasting hyperglycemia, glucose intolerance, as well as, elevated circulating adrenaline and cholesterol when measured at 13 wk, however, these responses were largely reversible following a 1 wk recovery. Moreover, the increases noted acutely after ozone exposure in non-esterified fatty acids and branched chain amino acid levels were not apparent following a subchronic exposure. Neither peripheral or tissue specific insulin resistance nor increased hepatic gluconeogenesis were present after subchronic ozone exposure. Instead, long-term ozone exposure lowered circulating insulin and severely impaired glucose-stimulated beta-cell insulin secretion. Thus, our findings in young-adult rats provide potential insights into epidemiological studies that show a positive association between ozone exposures and type 1 diabetes. Ozone-induced beta-cell dysfunction may secondarily contribute to other tissue-specific metabolic alterations following chronic exposure due to impaired regulation of glucose, lipid, and protein metabolism. PMID:27368153

Past, present and future concentrations of ground-level ozone and potential impacts on ecosystems and human health in northern Europe.

PubMed

Karlsson, Per Erik; Klingberg, Jenny; Engardt, Magnuz; Andersson, Camilla; Langner, Joakim; Karlsson, Gunilla Pihl; Pleijel, Håkan

2017-01-15

This review summarizes new information on the current status of ground-level ozone in Europe north of the Alps. There has been a re-distribution in the hourly ozone concentrations in northern Europe during 1990-2015. The highest concentrations during summer daytime hours have decreased while the summer night-time and winter day- and night-time concentrations have increased. The yearly maximum 8-h mean concentrations ([O 3 ] 8h,max ), a metric used to assess ozone impacts on human health, have decreased significantly during 1990-2015 at four out of eight studied sites in Fennoscandia and northern UK. Also the annual number of days when the yearly [O 3 ] 8h,max exceeded the EU Environmental Quality Standard (EQS) target value of 60ppb has decreased. In contrast, the number of days per year when the yearly [O 3 ] 8h,max exceeded 35ppb has increased significantly at two sites, while it decreased at one far northern site. [O 3 ] 8h,max is predicted not to exceed 60ppb in northern UK and Fennoscandia after 2020. However, the WHO EQS target value of 50ppb will still be exceeded. The AOT40 May-July and AOT40 April-September metrics, used for the protection of vegetation, have decreased significantly at three and four sites, respectively. The EQS for the protection of forests, AOT40 April-September 5000ppbh, is projected to no longer be exceeded for most of northern Europe sometime before the time period 2040-2059. However, if the EQS is based on Phytotoxic Ozone Dose (POD), POD 1 , it may still be exceeded by 2050. The increasing trend for low and medium range ozone concentrations in combination with a decrease in high concentrations indicate that a new control strategy, with a larger geographical scale than Europe and including methane, is needed for ozone abatement in northern Europe. Copyright © 2016 Elsevier B.V. All rights reserved.

Ozone Observations using Ozonesonde over the Himalaya from Pokhara, Nepal.

NASA Astrophysics Data System (ADS)

Dhungel, S.; Cullis, P.; Johnson, B.; Thompson, A. M.; Witte, J. C.; Panday, A. K.

2016-12-01

In recent years, transport of emissions from the Indo-Gangetic Plains (IGP), which covers parts of Pakistan, Nepal, India, Bangladesh has increased. Ozone pre-cursors like methane, nitrogen oxides, volatile organic carbons, and carbon monoxide from diesel based vehicular emission, biofuel and biomass burning, agricultural activities dominate the total emissions from the IGP. Synoptic circulation patterns along with local weather systems transport pollutants from the IGP up the Himalayan valleys to the Tibetan plateau. After being emitted, these pollutants are photochemically converted into tropospheric ozone - a short-lived climate pollutant that can increase atmospheric warming, alter processes of cloud formation, and in turn, influence precipitation levels and reduce carbon absorptivity in plants leading to decline in crop yields. However, little is known about vertical profiles of ozone concentration on the southern slopes of the Himalaya. Vertical ozone profiles were sampled from December 18th, 2015 to January 8th, 2016 from Pokhara (28.23°N, 83.99°E, 827m asl), Nepal using ozonesondes. Pokhara is located about 30km south of the Annapurna Himalaya, thus providing an ideal location to profile vertical ozone concentration south of the Himalaya. We launched one, two or four ozonesondes per day to examine the vertical resolution of ozone south of the Himalaya for the first time, and to understand the contribution of tropospheric and stratospheric sources. Here we present results from the 37 ozonesonde launches from Pokhara to examine: (i) how emissions from the IGP contribute to the vertical resolution of ozone, and (ii) if Himalayan orography provides an efficient path for stratosphere-troposphere air mass exchange under dry conditions. Our results show no signals of stratospheric air mass exchange. The results indicate higher levels of ozone within the boundary layer and lower troposphere. These higher values in the lower troposphere during winter seasons may be a result of longer residence times of the air mass resulting in photochemical build-up despite reduced insolation. Our observations are also essential to help infer ozone trends near the Himalaya, where there is currently inadequate spatial and temporal data coverage.

Impacts of the large increase in international ship traffic 2000-2007 on tropospheric ozone and methane.

PubMed

Dalsøren, Stig B; Eide, Magnus S; Myhre, Gunnar; Endresen, Oyvind; Isaksen, Ivar S A; Fuglestvedt, Jan S

2010-04-01

The increase in civil world fleet ship emissions during the period 2000-2007 and the effects on key tropospheric oxidants are quantified using a global Chemical Transport Model (CTM). We estimate a substantial increase of 33% in global ship emissions over this period. The impact of ship emissions on tropospheric oxidants is mainly caused by the relatively large fraction of NOx in ship exhaust. Typical increases in yearly average surface ozone concentrations in the most impacted areas are 0.5-2.5 ppbv. The global annual mean radiative forcing due to ozone increases in the troposphere is 10 mWm(-2) over the period 2000-2007. We find global average tropospheric OH increase of 1.03% over the same period. As a result of this the global average tropospheric methane concentration is reduced by approximately 2.2% over a period corresponding to the turnover time. The resulting methane radiative forcing is -14 mWm(-2) with an additional contribution of -6 mWm(-2) from methane induced reduction in ozone. The net forcing of the ozone and methane changes due to ship emissions changes between 2000 and 2007 is -10 mWm(-2). This is significant compared to the net forcing of these components in 2000. Our findings support earlier observational studies indicating that ship traffic may be a major contributor to recent enhancement of background ozone at some coastal stations. Furthermore, by reducing global mean tropospheric methane by 40 ppbv over its turnover time it is likely to contribute to the recent observed leveling off in global mean methane concentration.

Seasonal Changes in Tropospheric Ozone Concentrations over South Korea and Its Link to Ozone Precursors

NASA Astrophysics Data System (ADS)

Jung, H. C.; Moon, B. K.; Wie, J.

2017-12-01

Concentration of tropospheric ozone over South Korea has steadily been on the rise in the last decades, mainly due to rapid industrializing and urbanizing in the Eastern Asia. To identify the characteristics of tropospheric ozone in South Korea, we fitted a sine function to the surface ozone concentration data from 2005 to 2014. Based on fitted sine curves, we analyzed the shifts in the dates on which ozone concentration reached its peak in the calendar year. Ozone monitoring sites can be classified into type types: where the highest annual ozone concentration kept occurring sooner (Esites) and those that kept occurring later (Lsites). The seasonal analysis shows that the surface ozone had increased more rapidly in Esites than in Lsites in the past decade during springtime and vice-versa during summertime. We tried to find the reason for the different seasonal trends with the relationship between ozone and ozone precursors. As a result, it was found that the changes in the ground-level ozone concentration in the spring and summer times are considerably influenced by changes in nitrogen dioxide concentration, and this is closely linked to the destruction (production) process of ozone by nitrogen dioxide in spring (summer). The link between tropospheric ozone and nitrogen dioxide discussed in this study will have to be thoroughly examined through climate-chemistry modeling in the future. Acknowledgements This research was supported by the Korea Ministry of Environment (MOE) as "Climate Change Correspondence Program."

Extensive halogen-mediated ozone destruction over the tropical Atlantic Ocean.

PubMed

Read, Katie A; Mahajan, Anoop S; Carpenter, Lucy J; Evans, Mathew J; Faria, Bruno V E; Heard, Dwayne E; Hopkins, James R; Lee, James D; Moller, Sarah J; Lewis, Alastair C; Mendes, Luis; McQuaid, James B; Oetjen, Hilke; Saiz-Lopez, Alfonso; Pilling, Michael J; Plane, John M C

2008-06-26

Increasing tropospheric ozone levels over the past 150 years have led to a significant climate perturbation; the prediction of future trends in tropospheric ozone will require a full understanding of both its precursor emissions and its destruction processes. A large proportion of tropospheric ozone loss occurs in the tropical marine boundary layer and is thought to be driven primarily by high ozone photolysis rates in the presence of high concentrations of water vapour. A further reduction in the tropospheric ozone burden through bromine and iodine emitted from open-ocean marine sources has been postulated by numerical models, but thus far has not been verified by observations. Here we report eight months of spectroscopic measurements at the Cape Verde Observatory indicative of the ubiquitous daytime presence of bromine monoxide and iodine monoxide in the tropical marine boundary layer. A year-round data set of co-located in situ surface trace gas measurements made in conjunction with low-level aircraft observations shows that the mean daily observed ozone loss is approximately 50 per cent greater than that simulated by a global chemistry model using a classical photochemistry scheme that excludes halogen chemistry. We perform box model calculations that indicate that the observed halogen concentrations induce the extra ozone loss required for the models to match observations. Our results show that halogen chemistry has a significant and extensive influence on photochemical ozone loss in the tropical Atlantic Ocean boundary layer. The omission of halogen sources and their chemistry in atmospheric models may lead to significant errors in calculations of global ozone budgets, tropospheric oxidizing capacity and methane oxidation rates, both historically and in the future.

Advanced oxidation processes on doxycycline degradation: monitoring of antimicrobial activity and toxicity.

PubMed

Spina-Cruz, Mylena; Maniero, Milena Guedes; Guimarães, José Roberto

2018-05-08

Advanced oxidation processes (AOPs) have been highly efficient in degrading contaminants of emerging concern (CEC). This study investigated the efficiency of photolysis, peroxidation, photoperoxidation, and ozonation at different pH values to degrade doxycycline (DC) in three aqueous matrices: fountain, tap, and ultrapure water. More than 99.6% of DC degradation resulted from the UV/H 2 O 2 and ozonation processes. Also, to evaluate the toxicity of the original solution and throughout the degradation time, antimicrobial activity tests were conducted using Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacteria, and acute toxicity test using the bioluminescent marine bacterium (Vibrio fischeri). Antimicrobial activity reduced as the drug degradation increased in UV/H 2 O 2 and ozonation processes, wherein the first process only 6 min was required to reduce 100% of both bacteria activity. In ozonation, 27.7 mg L -1 of ozone was responsible for reducing 100% of the antimicrobial activity. When applied the photoperoxidation process, an increase in the toxicity occurred as the high levels of degradation were achieved; it means that toxic intermediates were formed. The ozonated solutions did not present toxicity.

Arctic “ozone hole” in a cold volcanic stratosphere

PubMed Central

Tabazadeh, A.; Drdla, K.; Schoeberl, M. R.; Hamill, P.; Toon, O. B.

2002-01-01

Optical depth records indicate that volcanic aerosols from major eruptions often produce clouds that have greater surface area than typical Arctic polar stratospheric clouds (PSCs). A trajectory cloud–chemistry model is used to study how volcanic aerosols could affect springtime Arctic ozone loss processes, such as chlorine activation and denitrification, in a cold winter within the current range of natural variability. Several studies indicate that severe denitrification can increase Arctic ozone loss by up to 30%. We show large PSC particles that cause denitrification in a nonvolcanic stratosphere cannot efficiently form in a volcanic environment. However, volcanic aerosols, when present at low altitudes, where Arctic PSCs cannot form, can extend the vertical range of chemical ozone loss in the lower stratosphere. Chemical processing on volcanic aerosols over a 10-km altitude range could increase the current levels of springtime column ozone loss by up to 70% independent of denitrification. Climate models predict that the lower stratosphere is cooling as a result of greenhouse gas built-up in the troposphere. The magnitude of column ozone loss calculated here for the 1999–2000 Arctic winter, in an assumed volcanic state, is similar to that projected for a colder future nonvolcanic stratosphere in the 2010 decade. PMID:11854461

Ecosystem-scale trade-offs between impacts of ozone and reactive nitrogen

NASA Astrophysics Data System (ADS)

Rowe, Ed; Hayes, Felicity; Sawicka, Kasia; Mills, Gina; Jones, Laurence; Moldan, Filip; Sereina, Bassin; van Dijk, Netty; Evans, Chris

2015-04-01

Nitrogen (N) deposition stimulates plant productivity in many terrestrial ecosystems. This is clearly beneficial for production agriculture and forestry, but increased litterfall and decreased ground-level light availability reduce the suitability of habitats for many biota (Jones et al., 2014). This mechanism (Hautier et al., 2009), together with the acidifying effects of N (Stevens et al., 2010), has caused considerable biodiversity loss at global scale. Ozone, by contrast, has the effect of reducing plant production, and a simple assessment would suggest that this might mitigate the effects of N pollution. We explored the interactions between ozone and nitrogen at mechanistic level using a version of the MADOC model (Rowe et al., 2014) modified to include effects of ozone. The model was tested against data from long-term monitoring and experimental sites with a focus on nitrogen and/or ozone effects. Effects on biodiversity were assessed by coupling the MADOC model to the MultiMOVE plant species model. We used this model-chain to explore trade-offs and synergies between the impacts of nitrogen and ozone on biodiversity and ecosystem biogeochemistry. In a review of the effects of ozone on ecosystem processes, two consistent effects were found: decreased net primary production due to damage to photosynthetic mechanisms; and an increase in litter nitrogen apparently caused by interference of ozone with the retranslocation process (Mills, in prep.). Insufficient evidence was found to justify inclusion of posited interactive mechanisms such as increased ozone susceptibility with greater nitrogen supply. However, the MADOC model illustrated emergent ozone-nitrogen interactions at ecosystem scale, for example an increase in N leaching due to decreased plant demand and greater litter N content. Empirical evidence for interactive effects of nitrogen and ozone at ecosystem scale is severely lacking, but simulated results were consistent with soil and soil solution observations from long-term experiments with N addition (bog at Whim Moss and coniferous forest at Gårdsjön) and ozone treatments (alpine grassland at Alp Flix). Effects of N pollution on biodiversity were well illustrated by the model chain. Acidification and eutrophication both tended to have negative effects on "positive indicator" species i.e. those that are distinctive for particular habitats, and neutral or positive effects on more ubiquitous species. Simulations suggested that ozone is likely to have beneficial effects on these distinctive species, principally because of decreased productivity. However, this may not occur in reality since responses of individual species to ozone vary considerably, and are not currently included in the model chain. We identify knowledge gaps which would be a useful focus for future experimental studies and surveys. Using relatively simple models of ecosystem biogeochemistry and species responses, together with an awareness of where simplifications might lead to unreliable conclusions, can help clarify research questions to be addressed in experimental studies. Hautier, Y. et al. 2009. Science 324, 636-638. Jones, L. et al. 2014. Ecosystem Services 7, 76-88. Mills, G. et al. in prep. Environmental Pollution. Rowe, E.C. et al. 2014. Environmental Pollution 184, 271-282. Stevens, C.J. et al. 2010. Functional Ecology 24, 478-484.

In vivo toxicity assessment of deoxynivalenol-contaminated wheat after ozone degradation.

PubMed

Wang, Li; Wang, Ying; Shao, Huili; Luo, Xiaohu; Wang, Ren; Li, Yongfu; Li, Yanan; Luo, Yingpeng; Zhang, Dongjie; Chen, Zhengxing

2017-01-01

The effect of ozone on deoxynivalenol (DON) detoxification was investigated. Ozone treatment could significantly reduce the levels of DON in wheat; 53% of DON in wheat was decomposed with 90 mg l -1 of ozone at a flow rate of 15 l min -1 for 4 h. The safety of DON-contaminated wheats (DCWs) untreated/treated by ozone was also evaluated. Institute of Cancer Research (ICR) mice were divided into a standard diet group and five experimental diet groups for a 51-day orally administration experiment. In the experiment, no remarkable changes in the general appearance of the mice were observed, and all the mice survived until the scheduled necropsy. The results of sub-chronic toxicity indicated that mice fed on DCWs alone had significantly decreased in body weight gain, thymus and spleen weights, ratios of liver, thymus and spleen to body weight, blood indices (red blood cell, haemoglobin, white blood cell), and pro-inflammatory cytokines (interleukin-6 (IL-6), tumour necrosis factor alpha (TNF-α)), while showing a significant increase in alanine aminotransferase, aspartate aminotransferase, blood creatinine and blood urea nitrogen levels. Histopathological examination indicate that DON elicited some degree of toxicity on the liver, kidney and thymus tissue. Mice fed on DCWs treated by ozone mitigated the adverse effects compared with mice fed on DCWs. All the results suggested that the deleterious effects of DON could be highly reduced by ozone, and ozone itself shows minor toxic effects on animals in this process.

Do trees smart from ozone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

Douglas-firs near Eatonville, Washington - 70 miles south of Seattle - are getting doses of ozone pollution at levels regularly found in Los Angeles. Ozone levels of 220 parts per billion (ppb) can make your eyes smart and give your Aunt Edna a doozy of a headache. University of Washington researchers are now trying to find if Douglas-fir is adversely affected by 220 ppb of ozone. They are also studying whether individual branches can reveal how whole trees respond to pollutants. Studying entire trees is tough so researchers hope to take the pulse of a tree by examining its branches.more » At the university's experimental forest, researchers have placed 12-foot-tall plastic-covered corrals around six Douglas-firs, each nine or 10 years old and up to 15 feet tall. Three of the trees receive filtered air while three others are blasted with 220 ppb of ozone for eight hours each day. Four individual branches on each tree are encased in their own plastic chambers. Two are dosed with filtered air and two with ozone. To date, the UW research is the only study in the US combining branch chambers with whole tree measurements. Now in its second year, the experiment is expected to yield information about growth and foliage health by measuring respiration, chlorophyll, photosynthesis, and nutrient uptake. Loss of tree vigor could lead to increased problems with pathogens and insects. In the summer of '88, surprisingly high levels of ozone - up to 196 ppb - were detected in forests downwind from Seattle, worse than the urban areas themselves.« less

Atmospheric Impacts of Emissions from Oil and Gas Development in the Uintah Basin, Utah, USA

NASA Astrophysics Data System (ADS)

Helmig, D.; Boylan, P. J.; Hueber, J.; Van Dam, B. A.; Mauldin, L.; Parrish, D. D.

2012-12-01

In the Uintah Basin in northeast Utah, USA, surface ozone levels during winter months have approached and on occasion exceeded the US National Ambient Air Quality Standard (NAAQS). Emissions from the extensive oil and gas exploration in this region are suspected to be the cause of these ozone episodes; however emission rates and photochemical processes are uncertain. During February 2012 continuous surface measurements and vertical profiling from a tethered balloon platform at the Horsepool site yielded high resolution boundary layer profile data on ozone and ozone precursor compounds, i.e. nitrogen oxides and volatile organic compounds as well as methane. Findings from this study were: 1. Surface ozone during the study period, which had no snow cover, did not exceed the NAAQS. 2. Nitrogen oxides varied from 1-50 ppbv pointing towards significant emission sources, likely from oil and gas operations. 3. Methane concentrations were elevated, reaching up to ~10 times its Northern Hemisphere (NH) atmospheric background. 3. Light non-methane hydrocarbons (NMHC) constituted the main fraction of volatile organic compounds. NMHC concentrations were highly elevated, exceeding levels seen in urban areas. 4. Ozone, methane, NOx and VOC showed distinct diurnal cycles, with large concentration increases seen at night, except for ozone, which showed the opposite behavior. 5. During nighttime concentrations of NOx, NMHC, and methane built up near the surface to levels that were much higher than their daytime concentrations. 6. Comparing NMHC to methane concentrations indicates a mass flux ratio of ~30% for total VOC/methane emissions for the Uintah Basin.

[Health impact of ozone in 13 Italian cities].

PubMed

Mitis, Francesco; Iavarone, Ivano; Martuzzi, Marco

2007-01-01

to estimate the health impact of ozone in 13 Italian cities over 200,000 inhabitants and to produce basic elements to permit the reproducibility of the study in other urban locations. the following data have been used: population data (2001), health data (2001 or from scientific literature), environmental data (2002-2004), from urban background monitoring station and concentration/response risk coefficients derived from recent metanalyses. The indicators SOMO35 and SOMO0 have been used as a proxi of the average exposure to calcolate attributable deaths (and years of life lost) and several causes of morbility for ozone concentrations over 70 microg/m3. acute mortality for all causes and for cardiovascular mortality, respiratory-related hospital admissions in elderly, asthma exacerbation in children and adults, minor restricted activity days, lower respiratory symptoms in children. over 500 (1900) deaths, the 0.6% (2.1%) of total mortality, equivalent to about 6000 (22,000) years of life lost are attributable to ozone levels over 70 microg/m3 in the 13 Italian cities under study. Larger figures, in the order of thousands, are attributable to less severe morbidity outcomes. The health impact of ozone in Italian towns is relevant in terms of acute mortality and morbidity, although less severe than PM10 impact. Background ozone levels are increasing. Abatement strategies for ozone concentrations should consider the whole summer and not only "peak" days and look at policies limiting the concentration of precursors produced by traffic sources. Relevant health benefits can be obtained also under levels proposed as guidelines in the present environmental regulations.

Increasing springtime ozone mixing ratios in the free troposphere over western North America.

PubMed

Cooper, O R; Parrish, D D; Stohl, A; Trainer, M; Nédélec, P; Thouret, V; Cammas, J P; Oltmans, S J; Johnson, B J; Tarasick, D; Leblanc, T; McDermid, I S; Jaffe, D; Gao, R; Stith, J; Ryerson, T; Aikin, K; Campos, T; Weinheimer, A; Avery, M A

2010-01-21

In the lowermost layer of the atmosphere-the troposphere-ozone is an important source of the hydroxyl radical, an oxidant that breaks down most pollutants and some greenhouse gases. High concentrations of tropospheric ozone are toxic, however, and have a detrimental effect on human health and ecosystem productivity. Moreover, tropospheric ozone itself acts as an effective greenhouse gas. Much of the present tropospheric ozone burden is a consequence of anthropogenic emissions of ozone precursors resulting in widespread increases in ozone concentrations since the late 1800s. At present, east Asia has the fastest-growing ozone precursor emissions. Much of the springtime east Asian pollution is exported eastwards towards western North America. Despite evidence that the exported Asian pollution produces ozone, no previous study has found a significant increase in free tropospheric ozone concentrations above the western USA since measurements began in the late 1970s. Here we compile springtime ozone measurements from many different platforms across western North America. We show a strong increase in springtime ozone mixing ratios during 1995-2008 and we have some additional evidence that a similar rate of increase in ozone mixing ratio has occurred since 1984. We find that the rate of increase in ozone mixing ratio is greatest when measurements are more heavily influenced by direct transport from Asia. Our result agrees with previous modelling studies, which indicate that global ozone concentrations should be increasing during the early part of the twenty-first century as a result of increasing precursor emissions, especially at northern mid-latitudes, with western North America being particularly sensitive to rising Asian emissions. We suggest that the observed increase in springtime background ozone mixing ratio may hinder the USA's compliance with its ozone air quality standard.

Increasing Springtime Ozone Mixing Ratios in the Free Troposphere Over Western North America

NASA Technical Reports Server (NTRS)

Cooper, O. R.; Parrish, D. D.; Stohl, A.; Trainer, M.; Nedelec, P.; Thouret, V.; Cammas, J. P.; Oltmans, S. J.; Johnson, B. J.; Tarasick, D.;

Ozone bioindicator

Treesearch

John W. Coulston; Mark J. Ambrose

2007-01-01

Why Is Ozone Important? Ground-level ozone occurs at phytotoxic levels in the United States (Lefohn and Pinkerton 1988). Elevated levels of ozone can cause foliar injury to several tree species, may cause growth loss, and can make trees more susceptible to insects and pathogens (Chappelka and Samuelson 1998). However, tree species have varying degrees of sensitivity to...

Estimating contribution of wildland fires to ambient ozone levels in National Parks in the Sierra Nevada, California

Treesearch

Haiganoush K. Preisler; Shiyuan (Sharon) Zhong; Annie Esperanza; Timothy J. Brown; Andrzej Bytnerowicz; Leland Tarnay

2010-01-01

Data from four continuous ozone and weather monitoring sites operated by the National Park Service in Sierra Nevada, California, are used to develop an ozone forecasting model and to estimate the contribution of wildland fires on ambient ozone levels. The analyses of weather and ozone data pointed to the transport of ozone precursors from the Central Valley as an...

The response of some common Egyptian plants to ozone and their use as biomonitors.

PubMed

El-Khatib, A A

2003-01-01

Relative sensitivity of five common Egyptian plant species namely, Senecio vulgaris, Malva parviflora, Sonchus oleraceus, Medicago sativa and Melilotus indicus to elevated levels of ozone has been studied. The plants were exposed to charcoal filtered air (CFA) and different levels of O3 (50 and 100 ppb) for 5 h per day. The studied parameters were recorded for five consecutive days after fumigation. The foliar injury varied significantly among species in a dose-dependent manner. Severe injury symptoms were recorded on the leaves of M. sativa. With the exception of M. parviflora, all species exhibited significant increases in the percentage reduction of the above-ground dry weight as a result of reductions in both leaf and stem dry weights. M. sativa showed a marked reduction in its relative growth rate at elevated levels of O3. The extent of chlorophyll a destruction was higher in both M. sativa and S. oleraceus than in the other species tested. No differences in the sensitivity of chlorophylls a+b and carotenoids to ozone levels were recorded in this work. Percentage reduction of ascorbic acid was higher in M. sativa and S. oleraceus, compared with the other species studied. With respect to relative percentages of proline, there was a significant difference in the responses of plants to ozone. According to the ozone resistance (R%), measured as relative growth rate, the test species were arranged in the descending order: M. parviflora>M. Indicus>S. Vulgaris>S. Oleraceus>M. sativa. In M. sativa, both determinant and correlation coefficients are well reflected in the relationship between its physiological response, its performance and ozone levels, supporting its recommendation as a candidate for biomonitoring in Egypt.

Ozonation of the pharmaceutical compound ranitidine: reactivity and kinetic aspects.

PubMed

Rivas, Javier; Gimeno, Olga; Encinas, Angel; Beltrán, Fernando

2009-07-01

Ranitidine has been ozonated under different operating conditions of pH, applied ozone dose, initial ranitidine concentration and presence or absence of free radical inhibitors. Results of ranitidine evolution with time indicate a high reactivity of this compound with molecular ozone. Mineralization levels achieved in the order of 20-25% suggest that the (CH3)2-N-CH2- moiety bonded to the furan ring could be separated from the rest of the ranitidine structure and further mineralized. Only alkaline conditions (pH=11) are capable of increasing TOC conversion up to values close to 70%. Determination of the direct ozonation rate constant for ranitidine by means of competitive kinetics reveals an unacceptable dependence of the aforementioned constant with the reference compound reactivity. It is hypothesised that only reference compounds with reactivity similar to the target species should be used.

Impact of preindustrial to present-day changes in short-lived pollutant emissions on atmospheric composition and climate forcing

NASA Astrophysics Data System (ADS)

Naik, Vaishali; Horowitz, Larry W.; Fiore, Arlene M.; Ginoux, Paul; Mao, Jingqiu; Aghedo, Adetutu M.; Levy, Hiram

2013-07-01

We describe and evaluate atmospheric chemistry in the newly developed Geophysical Fluid Dynamics Laboratory chemistry-climate model (GFDL AM3) and apply it to investigate the net impact of preindustrial (PI) to present (PD) changes in short-lived pollutant emissions (ozone precursors, sulfur dioxide, and carbonaceous aerosols) and methane concentration on atmospheric composition and climate forcing. The inclusion of online troposphere-stratosphere interactions, gas-aerosol chemistry, and aerosol-cloud interactions (including direct and indirect aerosol radiative effects) in AM3 enables a more complete representation of interactions among short-lived species, and thus their net climate impact, than was considered in previous climate assessments. The base AM3 simulation, driven with observed sea surface temperature (SST) and sea ice cover (SIC) over the period 1981-2007, generally reproduces the observed mean magnitude, spatial distribution, and seasonal cycle of tropospheric ozone and carbon monoxide. The global mean aerosol optical depth in our base simulation is within 5% of satellite measurements over the 1982-2006 time period. We conduct a pair of simulations in which only the short-lived pollutant emissions and methane concentrations are changed from PI (1860) to PD (2000) levels (i.e., SST, SIC, greenhouse gases, and ozone-depleting substances are held at PD levels). From the PI to PD, we find that changes in short-lived pollutant emissions and methane have caused the tropospheric ozone burden to increase by 39% and the global burdens of sulfate, black carbon, and organic carbon to increase by factors of 3, 2.4, and 1.4, respectively. Tropospheric hydroxyl concentration decreases by 7%, showing that increases in OH sinks (methane, carbon monoxide, nonmethane volatile organic compounds, and sulfur dioxide) dominate over sources (ozone and nitrogen oxides) in the model. Combined changes in tropospheric ozone and aerosols cause a net negative top-of-the-atmosphere radiative forcing perturbation (-1.05 W m-2) indicating that the negative forcing (direct plus indirect) from aerosol changes dominates over the positive forcing due to ozone increases, thus masking nearly half of the PI to PD positive forcing from long-lived greenhouse gases globally, consistent with other current generation chemistry-climate models.

Stratospheric ozone depletion due to nitrous oxide: influences of other gases

PubMed Central

Portmann, R. W.; Daniel, J. S.; Ravishankara, A. R.

2012-01-01

The effects of anthropogenic emissions of nitrous oxide (N2O), carbon dioxide (CO2), methane (CH4) and the halocarbons on stratospheric ozone (O3) over the twentieth and twenty-first centuries are isolated using a chemical model of the stratosphere. The future evolution of ozone will depend on each of these gases, with N2O and CO2 probably playing the dominant roles as halocarbons return towards pre-industrial levels. There are nonlinear interactions between these gases that preclude unambiguously separating their effect on ozone. For example, the CH4 increase during the twentieth century reduced the ozone losses owing to halocarbon increases, and the N2O chemical destruction of O3 is buffered by CO2 thermal effects in the middle stratosphere (by approx. 20% for the IPCC A1B/WMO A1 scenario over the time period 1900–2100). Nonetheless, N2O is expected to continue to be the largest anthropogenic emission of an O3-destroying compound in the foreseeable future. Reductions in anthropogenic N2O emissions provide a larger opportunity for reduction in future O3 depletion than any of the remaining uncontrolled halocarbon emissions. It is also shown that 1980 levels of O3 were affected by halocarbons, N2O, CO2 and CH4, and thus may not be a good choice of a benchmark of O3 recovery. PMID:22451111

Impact of biogenic very short-lived bromine on the Antarctic ozone hole during the 21st century

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fernandez, Rafael P.; Kinnison, Douglas E.; Lamarque, Jean -Francois

Active bromine released from the photochemical decomposition of biogenic very short-lived bromocarbons (VSL Br) enhances stratospheric ozone depletion. Based on a dual set of 1960–2100 coupled chemistry–climate simulations (i.e. with and without VSL Br), we show that the maximum Antarctic ozone hole depletion increases by up to 14 % when natural VSL Br are considered, which is in better agreement with ozone observations. The impact of the additional 5 pptv VSL Br on Antarctic ozone is most evident in the periphery of the ozone hole, producing an expansion of the ozone hole area of ~5 million km 2, which is equivalentmore » in magnitude to the recently estimated Antarctic ozone healing due to the implementation of the Montreal Protocol. We find that the inclusion of VSL Br in CAM-Chem (Community Atmosphere Model with Chemistry, version 4.0) does not introduce a significant delay of the modelled ozone return date to 1980 October levels, but instead affects the depth and duration of the simulated ozone hole. Our analysis further shows that total bromine-catalysed ozone destruction in the lower stratosphere surpasses that of chlorine by the year 2070 and indicates that natural VSL Br chemistry would dominate Antarctic ozone seasonality before the end of the 21st century. As a result, this work suggests a large influence of biogenic bromine on the future Antarctic ozone layer.« less

Impact of biogenic very short-lived bromine on the Antarctic ozone hole during the 21st century

DOE PAGES

Fernandez, Rafael P.; Kinnison, Douglas E.; Lamarque, Jean -Francois; ...

2017-02-03

Active bromine released from the photochemical decomposition of biogenic very short-lived bromocarbons (VSL Br) enhances stratospheric ozone depletion. Based on a dual set of 1960–2100 coupled chemistry–climate simulations (i.e. with and without VSL Br), we show that the maximum Antarctic ozone hole depletion increases by up to 14 % when natural VSL Br are considered, which is in better agreement with ozone observations. The impact of the additional 5 pptv VSL Br on Antarctic ozone is most evident in the periphery of the ozone hole, producing an expansion of the ozone hole area of ~5 million km 2, which is equivalentmore » in magnitude to the recently estimated Antarctic ozone healing due to the implementation of the Montreal Protocol. We find that the inclusion of VSL Br in CAM-Chem (Community Atmosphere Model with Chemistry, version 4.0) does not introduce a significant delay of the modelled ozone return date to 1980 October levels, but instead affects the depth and duration of the simulated ozone hole. Our analysis further shows that total bromine-catalysed ozone destruction in the lower stratosphere surpasses that of chlorine by the year 2070 and indicates that natural VSL Br chemistry would dominate Antarctic ozone seasonality before the end of the 21st century. As a result, this work suggests a large influence of biogenic bromine on the future Antarctic ozone layer.« less

Projection of Changes in Regional Climate and Air Quality in the Great Lakes Basin between 2000 and 2050 for the RCP8.5 Emissions Scenario using the GEM-AQ Model

NASA Astrophysics Data System (ADS)

Lupu, A.; Semeniuk, K.; McConnell, J. C.; Kaminski, J. W.; Toyota, K.; Neary, L.

2012-12-01

The Global Environmental Multiscale Air Quality (GEM-AQ) model was run in global and limited area model (LAM) modes for the baseline year 2000 and one future year, 2050, on three different horizontal grids of increasing resolution from global (1.5°) to North American (LAM, 0.45°) to Ontario regional scale (LAM, 0.15°). For the future simulation we used the high greenhouse emissions scenario RCP8.5. Boundary conditions for the LAM runs were taken from the coarser resolution runs. All simulations had 54 vertical sigma-pressure hybrid levels from the ground to the stratopause (˜50 km), which should give a good representation of ozone injection to the troposphere from the stratosphere. The model uses the interactive land surface scheme ISBA. Sea surface and lake temperatures are prescribed, but ice cover is partially interactive based on prescribed fields. A lake model, FLAKE, was coupled to GEM-AQ in order to capture the impacts of the Great Lakes on the meteorology when the model is run at high resolution. For the Ontario regional simulation the interactive lake model allowed for self-consistent water temperatures and moisture fluxes. The simulation for the year 2000 shows that the model is able to reproduce the observed monthly surface temperatures across the US. The monthly surface ozone is reproduced at the level of detail of most other air quality models with year 2000 weather as opposed to a free run forced by SSTs. Our year 2050 simulation shows that ozone levels during the summer throughout most of Ontario and Canada will increase. Regions south of the latitude of Lake Superior will generally see decreased levels of summer (JJA) ozone, except for around large urban areas such as Toronto, Chicago and Montreal. However, NOx levels will decrease during the summer, reflecting decreased emissions. Ozone levels in the US will generally improve. Other indices rather than simple averages yield a different perspective. If the MDA8 ozone metric and NO2 one-hour 98th percentile are used, then it is found that air quality across Canada and US will generally improve. From the perspective of meteorology, the most significant surface warming that is likely to occur by 2050 is during winter. The winter warming also reflects changes in large scale circulation with baroclinic eddy storm tracks moving north. Winter warming contributes to a surface ozone increase by 2050 in spite of reduced emissions. In addition, we note that in the Ontario region and environs for 2050 there is a significant increase (˜40) in the number of DD5 days, i.e. days where the temperature is above 5°C, a metric useful for the length of the growing season for agriculture. This also means that conditions that impact forests and movement of disease vectors will also change.

Global Ozone Distribution relevant to Human Health: Metrics and present day levels from the Tropospheric Ozone Assessment Report (TOAR)

NASA Astrophysics Data System (ADS)

Fleming, Z. L.; Doherty, R. M.; von Schneidemesser, E.; Cooper, O. R.; Malley, C.; Colette, A.; Xu, X.; Pinto, J. P.; Simpson, D.; Schultz, M. G.; Hamad, S.; Moola, R.; Solberg, S.; Feng, Z.

2017-12-01

Using stations from the TOAR surface ozone database, this study quantifies present-day global and regional distributions of five ozone metrics relevant for both short-term and long-term human exposure. These metrics were explored at ozone monitoring sites globally, and re-classified for this project as urban or non-urban using population densities and night-time lights. National surface ozone limit values are usually related to an annual number of exceedances of daily maximum 8-hour running mean (MDA8), with many countries not even having any ozone limit values. A discussion and comparison of exceedances in the different ozone metrics, their locations and the seasonality of exceedances provides clues as to the regions that potentially have more serious ozone health implications. Present day ozone levels (2010-2014) have been compared globally and show definite geographical differences (see Figure showing the annual 4th highest MDA8 for present day ozone for all non-urban stations). Higher ozone levels are seen in western compared to eastern US, and between southern and northern Europe, and generally higher levels in east Asia. The metrics reflective of peak concentrations show highest values in western North America, southern Europe and East Asia. A number of the metrics show similar distributions of North-South gradients, most prominent across Europe and Japan. The interquartile range of the regional ozone metrics was largest in East Asia, higher for urban stations in Asia but higher for non-urban stations in Europe and North America. With over 3000 monitoring stations included in this analysis and despite the higher densities of monitoring stations in Europe, north America and East Asia, this study provides the most comprehensive global picture to date of surface ozone levels in terms of health-relevant metrics.

Procedures for estimating the frequency of commercial airline flights encountering high cabin ozone levels

NASA Technical Reports Server (NTRS)

Holdeman, J. D.

1979-01-01

Three analytical problems in estimating the frequency at which commercial airline flights will encounter high cabin ozone levels are formulated and solved: namely, estimating flight-segment mean levels, estimating maximum-per-flight levels, and estimating the maximum average level over a specified flight interval. For each problem, solution procedures are given for different levels of input information - from complete cabin ozone data, which provides a direct solution, to limited ozone information, such as ambient ozone means and standard deviations, with which several assumptions are necessary to obtain the required estimates. Each procedure is illustrated by an example case calculation that uses simultaneous cabin and ambient ozone data obtained by the NASA Global Atmospheric Sampling Program. Critical assumptions are discussed and evaluated, and the several solutions for each problem are compared. Example calculations are also performed to illustrate how variations in lattitude, altitude, season, retention ratio, flight duration, and cabin ozone limits affect the estimated probabilities.

The Ozone Problem | Ground-level Ozone | New England | US ...

EPA Pesticide Factsheets

2017-04-10

Many factors impact ground-level ozone development, including temperature, wind speed and direction, time of day, and driving patterns. Due to its dependence on weather conditions, ozone is typically a summertime pollutant and a chief component of summertime smog.

A statistical model for forecasting hourly ozone levels during fire season

Treesearch

Haiganoush K. Preisler; Shiyuan (Sharon) Zhong; Annie Esperanza; Leland Tarnay; Julide Kahyaoglu-Koracin

2009-01-01

Concerns about smoke from large high-intensity and managed low intensity fires have been increasing during the past decade. Because smoke from large high-intensity fires are known to contain and generate secondary fine particles (PM2.5) and ozone precursors, the effect of fires on air quality in the southern Sierra Nevada is a serious management...

Fate of return activated sludge after ozonation: an optimization study for sludge disintegration.

PubMed

Demir, Ozlem; Filibeli, Ayse

2012-09-01

The effects of ozonation on sludge disintegration should be investigated before the application of ozone during biological treatment, in order to minimize excess sludge production. In this study, changes in sludge and supernatant after ozonation of return activated sludge were investigated for seven different ozone doses. The optimum ozone dose to avoid inhibition of ozonation and high ozone cost was determined in terms of disintegration degree as 0.05 g O3/gTS. Suspended solid and volatile suspended solid concentrations of sludge decreased by 77.8% and 71.6%, respectively, at the optimum ozone dose. Ozonation significantly decomposed sludge flocs. The release of cell contents was proved by the increase of supernatant total nitrogen (TN) and phosphorus (TP). While TN increased from 7 mg/L to 151 mg/L, TP increased from 8.8 to 33 mg/L at the optimum ozone dose. The dewaterability and filterability characteristics of the ozonated sludge were also examined. Capillary suction time increased with increasing ozone dosage, but specific resistance to filtration increased to a specific value and then decreased dramatically. The particle size distribution changed significantly as a result of floc disruption at an optimum dose of 0.05 gO3/gTS.

When Will the Antarctic Ozone Hole Recover?

NASA Technical Reports Server (NTRS)

Newman, Paul A.

2006-01-01

The Antarctic ozone hole demonstrates large-scale, man-made affects on our atmosphere. Surface observations now show that human produced ozone depleting substances (ODSs) are declining. The ozone hole should soon start to diminish because of this decline. In this talk we will demonstrate an ozone hole parametric model. This model is based upon: 1) a new algorithm for estimating 61 and Br levels over Antarctica and 2) late-spring Antarctic stratospheric temperatures. This parametric model explains 95% of the ozone hole area's variance. We use future ODS levels to predict ozone hole recovery. Full recovery to 1980 levels will occur in approximately 2068. The ozone hole area will very slowly decline over the next 2 decades. Detection of a statistically significant decrease of area will not occur until approximately 2024. We further show that nominal Antarctic stratospheric greenhouse gas forced temperature change should have a small impact on the ozone hole.

When Will the Antarctic Ozone Hole Recover?

NASA Technical Reports Server (NTRS)

Newman, Paul A.; Nash, Eric R.; Kawa, S. Randolph; Montzka, Stephen A.; Schauffler, Sue

2006-01-01

The Antarctic ozone hole demonstrates large-scale, man-made affects on our atmosphere. Surface observations now show that human produced ozone depleting substances (ODSs) are declining. The ozone hole should soon start to diminish because of this decline. Herein we demonstrate an ozone hole parametric model. This model is based upon: 1) a new algorithm for estimating C1 and Br levels over Antarctica and 2) late-spring Antarctic stratospheric temperatures. This parametric model explains 95% of the ozone hole area s variance. We use future ODS levels to predict ozone hole recovery. Full recovery to 1980 levels will occur in approximately 2068. The ozone hole area will very slowly decline over the next 2 decades. Detection of a statistically significant decrease of area will not occur until approximately 2024. We further show that nominal Antarctic stratospheric greenhouse gas forced temperature change should have a small impact on the ozone hole.

Evaluation of sorghum flour functionality and quality characteristics of gluten-free bread and cake as influenced by ozone treatment.

PubMed

Marston, Kathryn; Khouryieh, Hanna; Aramouni, Fadi

2015-12-01

Commercially milled food-grade sorghum flour was subjected to ozone at the rate of 0.06 L/min for 15, 30, and 45 min. The pH of ozone-treated flour decreased as exposure time increased. The L* (lightness) values of sorghum flour significantly increased (p < 0.05), while the b* (yellowness) values significantly decreased as ozone exposure time increased. Peak viscosity significantly increased as time of ozonation increased from 0 to 45 min. Results showed that gluten-free cake volume significantly increased as ozonation time increased. Additionally, longer ozonation exposure times increased cells per slice area, lightness, and slice brightness values in gluten-free cakes while reducing crumb firmness. Despite improving lightness and slice brightness values, ozonation did not significantly increase the specific volume of gluten-free batter-based bread. While ozonation improved the volume and texture in cakes, it did not have the same positive effects on gluten-free bread. Bread made from ozonated sorghum flour had an open ragged structure with equivalent volume to the control flour. In both applications, the increased brightness and lightness values due to ozone exposure is recommended to increase the acceptability of sorghum products. © The Author(s) 2014.

Ozone impedes the ability of a herbivore to find its host

NASA Astrophysics Data System (ADS)

Fuentes, Jose D.; Roulston, T.'ai H.; Zenker, John

2013-03-01

Plant-emitted hydrocarbons mediate several key interactions between plants and insects. They enhance the ability of pollinators and herbivores to locate suitable host plants, and parasitoids to locate herbivores. While plant volatiles provide strong chemical signals, these signals are potentially degraded by exposure to pollutants such as ozone, which has increased in the troposphere and is projected to continue to increase over the coming decades. Despite the potential broad ecological significance of reduced plant signaling effectiveness, few studies have examined behavioral responses of insects to their hosts in polluted environments. Here, we use a laboratory study to test the effect of ozone concentration gradients on the ability of the striped cucumber beetle (Acalymma vittatum) to locate flowers of its host plant, Cucurbita foetidissima. Y-tube experiments showed that ozone mixing ratios below 80 parts per billion (ppb) resulted in beetles moving toward their host plant, but levels above 80 ppb resulted in beetles moving randomly with respect to host location. There was no evidence that beetles avoided polluted air directly. The results show that ozone pollution has great potential to perniciously alter key interactions between plants and animals.

Acid mist and ozone effects on the leaf chemistry of two western conifer species

NASA Technical Reports Server (NTRS)

Westman, Walter E.; Temple, Patrick J.

1989-01-01

The effects of ozone and acid-mist exposures on the leaf chemistry of Jeffrey pine and giant sequoia seedlings grown in filtered-air greenhouses were investigated. Acid-mist treatments (pH 4.1, 3.4, 2.7, or 2.0) were administered for 3 h, and ozone exposures (0, 0.10, and 0.20 microliter/liter), which followed acid-mist treatments, for 4 h, each for three days a week for six to nine weeks. It was found that seedlings were more susceptible to acid-mist and acid mist/ozone combinations, than to ozone alone. Acid mist treatment resulted in higher levels of nitrogen and sulfur (both present in acid mist) as well as Na. Leaves of giant sequoia exhibited increased K and decreased Mn, while Jeffrey pine showed increases in Fe and Mn. In sequoia leaves, concentrations of Ca, Mg, and Ba decreased. Acid treatment also reduced chlorophyll b concentrations in both conifer species. Extensive changes induced by acid mist are consistent with earlier observations of changes in spectral reflectance of conifer seedlings observed after three weeks of fumigation.

Ozone Climatology for Portsmouth, NH 1978-2002

NASA Astrophysics Data System (ADS)

Wake, C. P.; Miller, S. T.

2003-12-01

Hourly ozone mixing ratios have been monitored in Portsmouth, NH since 1978 for the typical "summer" ozone season (April to October) by the New Hampshire Department of Environmental Services. This 25 year record provides the basis to investigate seasonal variability in daily summertime ozone levels in Portsmouth NH and evaluate the relationship between ozone mixing ratios, temperature, precipitation, and the state of El Niño/Southern Oscillation. The overall goal of this research is to identify significant relationships between high ozone days and a suite of climate variables. The mean daily ozone mixing ratio in Portsmouth from 1977 through 2002 was 40 ppbv (sd 17 ppbv) with a mean of 6 days per summer when maxiumum 8 hour ozone levels exceed the 80 ppbv level. The highest ozone levels usually occur during June, July and August (with a peak in July), but high ozone days also occur May and September. April and October rarely experience high ozone. High ozone in coastal New Hampshire (and for most of New England) occurs predominantly on days when maximum temperatures are above 85 oF, although there are also may hot days when ozone levels do not reach elevated levels. Analysis of the relationship between number of days per year when 8 hour ozone is greater than 80 ppbv and maximum temperatures are greater than 85 oF indicates that there is a positive correlation (r = 0.60). Surprisingly, there is not a strong inverse relationship between ozone days and precipitation. For example, over the last 25 years, 1988 clearly stands out with 20 days with maximum 8 hour ozone above 80 ppbv. However, 1988 also experienced considerable precipitation in July and August (14.1 inches compared to the climatological mean of 6.7 inches) and relatively few days without precipitation (38 compared to the climatological mean of 44). There are differences in temperature, precipitation, and ozone levels in Portsmouth during years that are classified as El Ni¤o and neutral, compared to La Nina years. However, we have only experienced one strong La Nina year in the past 25 years, so the results must be viewed with caution. The La Nina year (1988) experience high ozone and more frequent hot days, as well as double the average precipitation. El Niño years experience slightly warmer, dryer and experience more frequent ozone days, although they are not significantly different from neutral years. Our results indicate that hot summers are indeed related to higher than average ozone levels, although there is considerable variability in this relationship. There does not appear to be a consistent ozone - precipitation relationship. Further work is needed to define these relationships for a larger number of stations throughout New England and also for comparison to broader synoptic to hemispheric circulation patterns and sea surface temperatures.

Bromine-Chlorine Coupling in the Antarctic Ozone Hole

NASA Technical Reports Server (NTRS)

Danilin, Michael Y.; Sze, Nien-Dak; Ko, Malcolm K. W.; Rodriquez, Jose M.; Prather, Michael J.

1996-01-01

The contribution from the chlorine and bromine species in the formation of the Antarctic ozone hole is evaluated. Since chlorine and bromine compounds are of different industrial origin, it is desirable, from a policy point of view, to be able to attribute chlorine-catalyzed loss of ozone with those reactions directly involving chlorine species, and likewise for bromine-catalyzed loss. In the stratosphere, however, most of the chemical families are highly coupled, and, for example, changes in the chlorine abundance will alter the partitioninig in other families and thus the rate of ozone loss. This modeling study examines formation of the Antarctic ozone hole for a wide range of bromine concentrations (5 - 25 pptv) and for chlorine concentrations typical of the last two decades (1.5, 2.5 and 3.5 ppbv). We follow the photochemical evolution of a single parcel of air, typical of the inner Antarctic vortex (50 mbar, 70 deg. S, NO(sub y) = 2 ppbv, with Polar Stratospheric Clouds(PSC)) from August 1 to November 1. For all of these ranges of chlorine and bromine loading, we would predict a substantial ozone hole (local depletion greater than 90%) within the de-nitrified, PSC- perturbed vortex. The contributions of the different catalytic cycles responsible for ozone loss are tabulated. The deep minimum in ozone is driven primarily by the chlorine abundance. As bromine levels decrease, the magnitude of the chlorine-catalyzed ozone loss increases to take up the slack. This is because bromine suppresses ClO by accelerating the conversion of ClO an Cl2O2 back to HCI. For this range of conditions, the local relative efficiency of ozone destruction per bromine atom to that per chlorine atom (alpha-factor) ranges from 33 to 55, decreasing with increase of bromine.

A Bayesian model for quantifying the change in mortality associated with future ozone exposures under climate change.

PubMed

Alexeeff, Stacey E; Pfister, Gabriele G; Nychka, Doug

2016-03-01

Climate change is expected to have many impacts on the environment, including changes in ozone concentrations at the surface level. A key public health concern is the potential increase in ozone-related summertime mortality if surface ozone concentrations rise in response to climate change. Although ozone formation depends partly on summertime weather, which exhibits considerable inter-annual variability, previous health impact studies have not incorporated the variability of ozone into their prediction models. A major source of uncertainty in the health impacts is the variability of the modeled ozone concentrations. We propose a Bayesian model and Monte Carlo estimation method for quantifying health effects of future ozone. An advantage of this approach is that we include the uncertainty in both the health effect association and the modeled ozone concentrations. Using our proposed approach, we quantify the expected change in ozone-related summertime mortality in the contiguous United States between 2000 and 2050 under a changing climate. The mortality estimates show regional patterns in the expected degree of impact. We also illustrate the results when using a common technique in previous work that averages ozone to reduce the size of the data, and contrast these findings with our own. Our analysis yields more realistic inferences, providing clearer interpretation for decision making regarding the impacts of climate change. © 2015, The International Biometric Society.

Systemic metabolic derangement, pulmonary effects, and insulin insufficiency following subchronic ozone exposure in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Desinia B.

Acute ozone exposure induces a classical stress response with elevated circulating stress hormones along with changes in glucose, protein and lipid metabolism in rats, with similar alterations in ozone-exposed humans. These stress-mediated changes over time have been linked to insulin resistance. We hypothesized that acute ozone-induced stress response and metabolic impairment would persist during subchronic episodic exposure and induce peripheral insulin resistance. Male Wistar Kyoto rats were exposed to air or 0.25 ppm or 1.00 ppm ozone, 5 h/day, 3 consecutive days/week (wk) for 13 wks. Pulmonary, metabolic, insulin signaling and stress endpoints were determined immediately after 13 wk ormore » following a 1 wk recovery period (13 wk + 1 wk recovery). We show that episodic ozone exposure is associated with persistent pulmonary injury and inflammation, fasting hyperglycemia, glucose intolerance, as well as, elevated circulating adrenaline and cholesterol when measured at 13 wk, however, these responses were largely reversible following a 1 wk recovery. Moreover, the increases noted acutely after ozone exposure in non-esterified fatty acids and branched chain amino acid levels were not apparent following a subchronic exposure. Neither peripheral or tissue specific insulin resistance nor increased hepatic gluconeogenesis were present after subchronic ozone exposure. Instead, long-term ozone exposure lowered circulating insulin and severely impaired glucose-stimulated beta-cell insulin secretion. Thus, our findings in young-adult rats provide potential insights into epidemiological studies that show a positive association between ozone exposures and type 1 diabetes. Ozone-induced beta-cell dysfunction may secondarily contribute to other tissue-specific metabolic alterations following chronic exposure due to impaired regulation of glucose, lipid, and protein metabolism. - Highlights: • Subchronic episodic ozone exposure caused pulmonary and metabolic effects. • These effects were largely reversible upon one week recovery. • Ozone exposure did not cause liver or muscle insulin resistance. • Subchronic ozone exposure led to decrease in serum insulin. • Ozone severely impaired beta cell insulin secretion in response to glucose.« less

Lower tropospheric ozone over India and its linkage to the South Asian monsoon

NASA Astrophysics Data System (ADS)

Lu, Xiao; Zhang, Lin; Liu, Xiong; Gao, Meng; Zhao, Yuanhong; Shao, Jingyuan

2018-03-01

Lower tropospheric (surface to 600 hPa) ozone over India poses serious risks to both human health and crops, and potentially affects global ozone distribution through frequent deep convection in tropical regions. Our current understanding of the processes controlling seasonal and long-term variations in lower tropospheric ozone over this region is rather limited due to spatially and temporally sparse observations. Here we present an integrated process analysis of the seasonal cycle, interannual variability, and long-term trends of lower tropospheric ozone over India and its linkage to the South Asian monsoon using the Ozone Monitoring Instrument (OMI) satellite observations for years 2006-2014 interpreted with a global chemical transport model (GEOS-Chem) simulation for 1990-2010. OMI observed lower tropospheric ozone over India averaged for 2006-2010, showing the highest concentrations (54.1 ppbv) in the pre-summer monsoon season (May) and the lowest concentrations (40.5 ppbv) in the summer monsoon season (August). Process analyses in GEOS-Chem show that hot and dry meteorological conditions and active biomass burning together contribute to 5.8 Tg more ozone being produced in the lower troposphere in India in May than January. The onset of the summer monsoon brings ozone-unfavorable meteorological conditions and strong upward transport, which all lead to large decreases in the lower tropospheric ozone burden. Interannually, we find that both OMI and GEOS-Chem indicate strong positive correlations (r = 0.55-0.58) between ozone and surface temperature in pre-summer monsoon seasons, with larger correlations found in high NOx emission regions reflecting NOx-limited production conditions. Summer monsoon seasonal mean ozone levels are strongly controlled by monsoon strengths. Lower ozone concentrations are found in stronger monsoon seasons mainly due to less ozone net chemical production. Furthermore, model simulations over 1990-2010 estimate a mean annual trend of 0.19 ± 0.07 (p value < 0.01) ppbv yr-1 in Indian lower tropospheric ozone over this period, which are mainly driven by increases in anthropogenic emissions with a small contribution (about 7 %) from global methane concentration increases.

The reciprocal relation between lightning and pollution and their impact over Kolkata, India.

PubMed

Middey, Anirban; Chaudhuri, Sutapa

2013-05-01

Aerosol loading in the atmosphere can cause increased lightning flashes, and those lightning flashes produce NOX , which reacts in sun light to produce surface ozone. The present study deals with the effect of surface pollutants on premonsoon (April-May) lightning activity over the station Kolkata (22.65° N, 88.45° E). Seven-year (2004-2010) premonsoon thunderstorms data are taken for the study. Different parameters like aerosol optical depth and cloud top temperature from the Moderate Resolution Imaging Spectroradiometer satellite products along with lightning flash data from Tropical Rainfall Measuring Mission's (TRMM) Lightning Imaging Sensor are analyzed. Some surface pollution parameters like suspended particulate matter, particulate matter 10, nitrogen oxides (NOX), and surface ozone (O₃) data during the same period are taken account for clear understanding of their association with lightning activity. Heights of convective condensation level and lifting condensation level are collected from radiosonde observations to anticipate about cloud base. It is found that increased surface pollution in a near storm environment is related to increased lightning flash rate, which results in increased surface NOX and consequently increased surface ozone concentration over the station Kolkata.

Rapid Transport of Stratospheric Ozone into the Planetary Boundary Layer over the Rocky Mountains

NASA Astrophysics Data System (ADS)

Skerlak, B.; Sprenger, M.; Pfahl, S.; Wernli, H.

2013-12-01

Stratosphere-troposphere exchange (STE) has important impacts on atmospheric chemistry: it changes the oxidative capacity of the troposphere and affects the climate system through the exchange of water vapor and ozone. Although a large part of tropospheric ozone is produced photochemically, significant amounts of stratospheric ozone can be brought into the troposphere during STE events. The relative importance of these two sources depends on the location of interest and transport characteristics. Of particular interest are so-called deep exchange events where ozone-rich stratospheric air reaches the planetary boundary layer (PBL) within a few days (deep STT). This rapid vertical transport can contribute to ozone concentrations at ground level which can impair plant and human physiology. It is therefore not only important to quantify the ozone flux across the tropopause but also to investigate the transport pathways after the crossing to identify affected areas at ground. Using a Lagrangian methodology and 33 years of ERA-Interim reanalysis data, we have compiled a global climatology of STE from which the mountainous areas in western North America can be identified as a 'hot spot' of deep STT, especially in boreal spring. To address the question of how the stratospheric air masses are transported into the PBL in more detail, we investigate case studies in this region with the mesoscale numerical weather prediction model COSMO. On this account, we initialize a passive tracer in the stratosphere using an elaborated 3D-labeling algorithm which applies the dynamical 2 pvu/380 K tropopause definition. This tracer is then advected by both resolved and parameterized processes and allows us to follow the stratospheric air masses along their journey into the mountainous PBL. Although this tracer does not directly represent a specific chemical species, its concentrations at the lowest model level can indicate when and where ozone levels at ground are likely to be influenced by the stratosphere. Concentration of a passive tracer (initialized in the stratosphere) at the lowest model level (10 m above ground) on May 3rd 00 UTC 2006. Around this time, increased levels of surface ozone (peaks up to 89 ppbv) were measured at Yellowstone National Park (YEL) in Wyoming. Contours indicate the geopotential at 500 hPa and show that the tracer is brought down from the stratosphere in the vicinity of a cyclone located to the northeast of YEL at this time.

Stratospheric ozone over the United States in summer linked to observations of convection and temperature via chlorine and bromine catalysis

PubMed Central

Anderson, James G.; Weisenstein, Debra K.; Bowman, Kenneth P.; Homeyer, Cameron R.; Smith, Jessica B.; Wilmouth, David M.; Sayres, David S.; Klobas, J. Eric; Dykema, John A.; Wofsy, Steven C.

2017-01-01

We present observations defining (i) the frequency and depth of convective penetration of water into the stratosphere over the United States in summer using the Next-Generation Radar system; (ii) the altitude-dependent distribution of inorganic chlorine established in the same coordinate system as the radar observations; (iii) the high resolution temperature structure in the stratosphere over the United States in summer that resolves spatial and structural variability, including the impact of gravity waves; and (iv) the resulting amplification in the catalytic loss rates of ozone for the dominant halogen, hydrogen, and nitrogen catalytic cycles. The weather radar observations of ∼2,000 storms, on average, each summer that reach the altitude of rapidly increasing available inorganic chlorine, coupled with observed temperatures, portend a risk of initiating rapid heterogeneous catalytic conversion of inorganic chlorine to free radical form on ubiquitous sulfate−water aerosols; this, in turn, engages the element of risk associated with ozone loss in the stratosphere over the central United States in summer based upon the same reaction network that reduces stratospheric ozone over the Arctic. The summertime development of the upper-level anticyclonic flow over the United States, driven by the North American Monsoon, provides a means of retaining convectively injected water, thereby extending the time for catalytic ozone loss over the Great Plains. Trusted decadal forecasts of UV dosage over the United States in summer require understanding the response of this dynamical and photochemical system to increased forcing of the climate by increasing levels of CO2 and CH4. PMID:28584119

Stratospheric ozone over the United States in summer linked to observations of convection and temperature via chlorine and bromine catalysis.

PubMed

Anderson, James G; Weisenstein, Debra K; Bowman, Kenneth P; Homeyer, Cameron R; Smith, Jessica B; Wilmouth, David M; Sayres, David S; Klobas, J Eric; Leroy, Stephen S; Dykema, John A; Wofsy, Steven C

2017-06-20

We present observations defining ( i ) the frequency and depth of convective penetration of water into the stratosphere over the United States in summer using the Next-Generation Radar system; ( ii ) the altitude-dependent distribution of inorganic chlorine established in the same coordinate system as the radar observations; ( iii ) the high resolution temperature structure in the stratosphere over the United States in summer that resolves spatial and structural variability, including the impact of gravity waves; and ( iv ) the resulting amplification in the catalytic loss rates of ozone for the dominant halogen, hydrogen, and nitrogen catalytic cycles. The weather radar observations of ∼2,000 storms, on average, each summer that reach the altitude of rapidly increasing available inorganic chlorine, coupled with observed temperatures, portend a risk of initiating rapid heterogeneous catalytic conversion of inorganic chlorine to free radical form on ubiquitous sulfate-water aerosols; this, in turn, engages the element of risk associated with ozone loss in the stratosphere over the central United States in summer based upon the same reaction network that reduces stratospheric ozone over the Arctic. The summertime development of the upper-level anticyclonic flow over the United States, driven by the North American Monsoon, provides a means of retaining convectively injected water, thereby extending the time for catalytic ozone loss over the Great Plains. Trusted decadal forecasts of UV dosage over the United States in summer require understanding the response of this dynamical and photochemical system to increased forcing of the climate by increasing levels of CO 2 and CH 4 .

Impact of Future Volcanic Eruptions on Stratospheric Ozone

NASA Astrophysics Data System (ADS)

Wilmouth, D. M.; Klobas, J. E.; Weisenstein, D.; Anderson, J. G.; Salawitch, R. J.

2017-12-01

Due to the anthropogenic release of chlorine-containing chemicals such as chlorofluorocarbons into the atmosphere in the twentieth century, a large volcanic eruption occurring today would initiate chemical reactions that reduce the thickness of the ozone layer. In the future, when atmospheric levels of chlorine are reduced, large volcanic eruptions are instead expected to increase the thickness of the ozone layer, but important details relevant to this shift in volcanic impact are not well known. Here we use the AER-2D chemical transport model to simulate a Pinatubo-like volcanic eruption in contemporary and future atmospheres. In particular, we explore the sensitivity of column ozone to volcanic eruption for four different climate change scenarios over the remainder of this century and also establish the importance of bromine-containing very short-lived substances (VSLS) in determining whether future eruptions will lead to ozone depletion. We find that the ozone layer will be vulnerable to volcanic perturbation for considerably longer than previously believed. Finally, we consider the impact on column ozone of inorganic halogens being co-injected into the stratosphere following future explosive eruptions using realistic hydrogen halide to sulfur dioxide ratios.

N-nitrosodimethylamine (NDMA) formation during ozonation of wastewater and water treatment polymers.

PubMed

Sgroi, Massimiliano; Roccaro, Paolo; Oelker, Gregg; Snyder, Shane A

2016-02-01

N-Nitrosodimethylamine (NDMA) formation by ozonation was investigated in the effluents of four different wastewater treatment plants destined for alternative reuse. Very high levels of NDMA formation were observed in wastewaters from treatment plants non operating with biological nitrogen removal. Selected experiments showed that hydroxyl radical did not have a significant role in NDMA formation during ozonation of wastewater. Furthermore, ozonation of three different polymers used for water treatment, including polyDADMAC, anionic polyacrylamide, and cationic polyacrylamide, spiked in wastewater did not increase the NDMA formation. Effluent organic matter (EfOM) likely reduced the availability of ozone in water able to react with polymers and quenched the produced ·OH radicals which limited polymer degradation and subsequent NDMA production. Excellent correlations were observed between NDMA formation, UV absorbance at 254 nm, and total fluorescence reduction. These data provide evidence that UV and fluorescence surrogates could be used for monitoring and/or controlling NDMA formation during ozonation. Copyright © 2015 Elsevier Ltd. All rights reserved.

NOx emissions and photochemistry associated with oil and gas production

NASA Astrophysics Data System (ADS)

Edwards, P.; Brown, S. S.; Dube, W. P.; Holloway, J. S.; Petron, G.; Kofler, J.; Warneke, C.; Williams, E. J.; Young, C. J.; Geiger, F.

2012-12-01

Winter ozone concentrations exceeding the current national ambient air quality standards (NAAQS) were observed in the Uintah basin, Utah, during the winters of 2009-2010 and 2010-2011. The chemistry driving these ground level ozone episodes, usually considered an urban summertime phenomenon, is currently poorly understood. Emissions of ozone precursor species in the Uintah basin are complex, and thought to be driven largely by extensive oil and gas development and production within the basin. The Uintah Basin Winter Ozone Study (UBWOS) was a major collaborative field study in February-March 2012, with the aim of increasing our understanding of this important air quality issue. Through the use of a comprehensive suite of instrumentation and multiple measurement platforms we have been able to better characterize the sources of important ozone precursors, in particular NOx and VOCs, within the basin. These observations enable an investigation of the unique aspects of local sources and chemistry that lead to winter ozone formation within the Uintah basin.

Ozone and childhood respiratory disease in three US cities: evaluation of effect measure modification by neighborhood socioeconomic status using a Bayesian hierarchical approach.

PubMed

O' Lenick, Cassandra R; Chang, Howard H; Kramer, Michael R; Winquist, Andrea; Mulholland, James A; Friberg, Mariel D; Sarnat, Stefanie Ebelt

2017-04-05

Ground-level ozone is a potent airway irritant and a determinant of respiratory morbidity. Susceptibility to the health effects of ambient ozone may be influenced by both intrinsic and extrinsic factors, such as neighborhood socioeconomic status (SES). Questions remain regarding the manner and extent that factors such as SES influence ozone-related health effects, particularly across different study areas. Using a 2-stage modeling approach we evaluated neighborhood SES as a modifier of ozone-related pediatric respiratory morbidity in Atlanta, Dallas, & St. Louis. We acquired multi-year data on emergency department (ED) visits among 5-18 year olds with a primary diagnosis of respiratory disease in each city. Daily concentrations of 8-h maximum ambient ozone were estimated for all ZIP Code Tabulation Areas (ZCTA) in each city by fusing observed concentration data from available network monitors with simulations from an emissions-based chemical transport model. In the first stage, we used conditional logistic regression to estimate ZCTA-specific odds ratios (OR) between ozone and respiratory ED visits, controlling for temporal trends and meteorology. In the second stage, we combined ZCTA-level estimates in a Bayesian hierarchical model to assess overall associations and effect modification by neighborhood SES considering categorical and continuous SES indicators (e.g., ZCTA-specific levels of poverty). We estimated ORs and 95% posterior intervals (PI) for a 25 ppb increase in ozone. The hierarchical model combined effect estimates from 179 ZCTAs in Atlanta, 205 ZCTAs in Dallas, and 151 ZCTAs in St. Louis. The strongest overall association of ozone and pediatric respiratory disease was in Atlanta (OR = 1.08, 95% PI: 1.06, 1.11), followed by Dallas (OR = 1.04, 95% PI: 1.01, 1.07) and St. Louis (OR = 1.03, 95% PI: 0.99, 1.07). Patterns of association across levels of neighborhood SES in each city suggested stronger ORs in low compared to high SES areas, with some evidence of non-linear effect modification. Results suggest that ozone is associated with pediatric respiratory morbidity in multiple US cities; neighborhood SES may modify this association in a non-linear manner. In each city, children living in low SES environments appear to be especially vulnerable given positive ORs and high underlying rates of respiratory morbidity.

The impact of drought on ozone dry deposition over eastern Texas

NASA Astrophysics Data System (ADS)

Huang, Ling; McDonald-Buller, Elena C.; McGaughey, Gary; Kimura, Yosuke; Allen, David T.

2016-02-01

Dry deposition represents a critical pathway through which ground-level ozone is removed from the atmosphere. Understanding the effects of drought on ozone dry deposition is essential for air quality modeling and management in regions of the world with recurring droughts. This work applied the widely used Zhang dry deposition algorithm to examine seasonal and interannual changes in estimated ozone dry deposition velocities and component resistances/conductances over eastern Texas during years with drought (2006 and 2011) as well as a year with slightly cooler temperatures and above average rainfall (2007). Simulated area-averaged daytime ozone dry deposition velocities ranged between 0.26 and 0.47 cm/s. Seasonal patterns reflected the combined seasonal variations in non-stomatal and stomatal deposition pathways. Daytime ozone dry deposition velocities during the growing season were consistently larger during 2007 compared to 2006 and 2011. These differences were associated with differences in stomatal conductances and were most pronounced in forested areas. Reductions in stomatal conductances under drought conditions were highly sensitive to increases in vapor pressure deficit and warmer temperatures in Zhang's algorithm. Reductions in daytime ozone deposition velocities and deposition mass during drought years were associated with estimates of higher surface ozone concentrations.

Enhanced charge transport and photovoltaic performance of PBDTTT-C-T/PC70BM solar cells via UV-ozone treatment.

PubMed

Adhikary, Prajwal; Venkatesan, Swaminathan; Adhikari, Nirmal; Maharjan, Purna P; Adebanjo, Olusegun; Chen, Jihua; Qiao, Qiquan

2013-10-21

In this work, the electron transport layer of PBDTTT-C-T/PC70BM polymer solar cells were subjected to UV-ozone treatment, leading to improved cell performances from 6.46% to 8.34%. The solar cell efficiency reached a maximum of 8.34% after an optimal 5 minute UV-ozone treatment, and then decreased if treated for a longer time. To the best of our knowledge, the mechanism behind the effects of UV-ozone treatment on the improvement of charge transport and cell performance is not fully understood. We have developed a fundamental understanding of the UV-ozone treatment mechanism, which explains both the enhancements in charge transport and photovoltaic performance at an optimal treatment time, and also the phenomenon whereby further treatment time leads to a drop in cell efficiency. Transient photocurrent measurements indicated that the cell charge transport times were 1370 ns, 770 ns, 832 ns, 867 ns, and 1150 ns for the 0 min, 5 min, 10 min, 15 min, and 20 min UV-ozone treatment times, respectively. Therefore the 5 min UV-ozone treatment time led to the shortest transport time and the most efficient charge transport in the cells. The 5 min UV-ozone treated sample exhibited the highest peak intensity (E2) in the Raman spectra of the treated films, at about 437 cm(-1), indicating that it possessed the best wurtzite phase crystallinity of the ZnO films. Further increasing the UV-ozone treatment time from 5 to 20 min induced the formation of p-type defects (e.g. interstitial oxygen atoms), pushing the ZnO Fermi-level further away from the vacuum level, and decreasing the wurtzite crystallinity.

Early physiological responses of Pinus pinea L. seedlings infected by Heterobasidion sp.pl. in an ozone-enriched atmospheric environment.

PubMed

Pollastrini, Martina; Luchi, Nicola; Michelozzi, Marco; Gerosa, Giacomo; Marzuoli, Riccardo; Bussotti, Filippo; Capretti, Paolo

2015-03-01

The presence of the American root-rot disease fungus Heterobasidion irregulare Garbel. & Otrosina was detected in Italian coastal pine forests (Pinus pinea L.) in addition to the common native species Heterobasidion annosum (Fries) Brefeld. High levels of tropospheric ozone (O3) as an atmospheric pollutant are usually experienced in Mediterranean pine forests. To explore the effect of interaction between the two Heterobasidion species and ozone pollution on P. pinea, an open-top chamber (OTC) experiment was carried out. Five-year-old P. pinea seedlings were inoculated with the fungal species considered (H. irregulare, H. annosum and mock-inoculation as control), and then exposed in charcoal-filtered open-top chambers (CF-OTC) and non-filtered ozone-enriched chambers (NF+) from July to the first week of August 2010 at the experimental facilities of Curno (North Italy). Fungal inoculation effects in an ozone-enriched environment were assessed as: (i) the length of the inoculation lesion; (ii) chlorophyll a fluorescence (ChlF) responses; and (iii) analysis of resin terpenes. Results showed no differences on lesion length between fungal and ozone treatments, whereas the short-term effects of the two stress factors on ChlF indicate an increased photosynthetic efficiency, thus suggesting the triggering of compensation/repair processes. The total amount of resin terpenes is enhanced by fungal infection of both species, but depressed by ozone to the levels observed in mock-inoculated plants. Variations in terpene profiles were also induced by stem base inoculations and ozone treatment. Ozone might negatively affect terpene defences making plants more susceptible to pathogens and insects. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Satellite Observations of Enhanced Tropospheric Ozone Associated with Biomass Burning in Africa and Madagascar

NASA Technical Reports Server (NTRS)

Aikin, A. C.; Ziemke, J. R.; Thorpe, A.; Einaudi, Franco (Technical Monitor)

2000-01-01

Tropospheric ozone over Africa and Madagascar is enhanced by 10 to 15 DU in October. This maximum coincides with the time of maximum biomass area burning in Africa and Madagascar. Ozone observations were made from 1979 to 1999 using the TOMS tropospheric ozone convective cloud differential method. As a result of easterly trade winds, ozone originating on Madagascar is transported to the west over the Mozambique Channel. In El Nino years higher level westerly winds descend to transport low level ozone easterly. This results in African continental ozone being transported east of Madagascar. Long range transport of African ozone is observed during El Nino periods.

Evaluation of ozone, nitrogen dioxide, and carbon monoxide at nine sites in Saudi Arabia during 2007.

PubMed

Butenhoff, Christopher L; Khalil, M Aslam K; Porter, William C; Al-Sahafi, Mohammed Saleh; Almazroui, Mansour; Al-Khalaf, Abdulrahman

2015-07-01

This paper presents a one-year record of in situ air-quality data from nine sites throughout Saudi Arabia. The data set is composed of hourly measurements of ozone (O3), nitrogen dioxide (NO2), and carbon monoxide (CO) at six of the largest cities in Saudi Arabia (Riyadh, Jeddah, Makkah, Yanbu, Dammam, Hafouf) and two remote locations in the mountainous southwestern region of Alsodah for the year 2007. The authors found that international O3 and CO standards were routinely exceeded throughout the year at many sites, and that exceedances increased during Ramadan (Sep. 12-Oct. 13), the Islamic month of fasting when much of normal daily activity is shifted to nighttime hours. In general NO2 and CO levels were higher in Saudi cities compared to U.S. cities of comparable population, while O3 levels were lower. There was a general trend for O3 and NO2 to be negatively correlated in Saudi cities in contrast to U.S. cities where the correlation is positive, suggesting that ozone chemistry in Saudi Arabia is limited by volatile organic compound emissions. This may be caused by low biogenic emissions from vegetation. Pollutant levels were lower at most Saudi sites during the four day Hajj period (Dec. 18-21) but higher in Makkah which receives millions of visitors during Hajj. The authors also found that ozone levels were elevated during the weekend (Thursday & Friday) relative to weekday levels despite lower NO2, a phenomenon known as the "weekend effect." As little air quality data is available from Saudi Arabia in the English-language literature, this data set fills a knowledge gap and improves understanding of air quality in an important but under-reported region of the world. Air quality measurements at nine sites in Saudi Arabia provide a detailed look at spatial and temporal patterns of ozone (O3), nitrogen dioxide (NO2), and carbon monoxide (CO). NO2 and CO levels increased in most cities during the fasting month of Ramadan, whereas O3 levels decreased. This led to an increased frequency of CO exceedances based on international standards. NO2 and CO also increased in Makkah during the Hajj pilgrimage. In general, NO2 and O3 levels were anticorrelated at most sites, suggesting that O3 chemistry is limited by volatile organic compound emissions throughout much of Saudi Arabia.

Local Structure and Surface Properties of CoxZn1-xO Thin Films for Ozone Gas Sensing.

PubMed

Catto, Ariadne C; Silva, Luís F da; Bernardi, Maria Inês B; Bernardini, Sandrine; Aguir, Khalifa; Longo, Elson; Mastelaro, Valmor R

2016-10-05

A detailed study of the structural, surface, and gas-sensing properties of nanostructured Co x Zn 1-x O films is presented. X-ray diffraction (XRD) analysis revealed a decrease in the crystallization degree with increasing Co content. The X-ray absorption near-edge structure (XANES) and X-ray photoelectron spectroscopies (XPS) revealed that the Co 2+ ions preferentially occupied the Zn 2+ sites and that the oxygen vacancy concentration increased as the amount of cobalt increased. Electrical measurements showed that the Co dopants not only enhanced the sensor response at low ozone levels (ca. 42 ppb) but also led to a decrease in the operating temperature and improved selectivity. The enhancement in the gas-sensing properties was attributed to the presence of oxygen vacancies, which facilitated ozone adsorption.

Analysis of a rapid increase of stratospheric ozone during late austral summer 2008 over Kerguelen (49.4° S, 70.3° E)

NASA Astrophysics Data System (ADS)

Bencherif, H.; El Amraoui, L.; Kirgis, G.; Leclair de Bellevue, J.; Hauchecorne, A.; Mzé, N.; Portafaix, T.

2010-07-01

This paper reports on an increase of ozone event observed over Kerguelen (49.4° S, 70.3° E) in relationship with large-scale isentropic transport. It is evidenced from ground-based observations, together with satellite global observations and assimilated fields. The study is based on the analyses of the first ozonesonde experiment never recorded at the Kerguelen site in the framework of a French campaign called ROCK that took place from April to August 2008. Comparisons and interpretations of the observed event are supported by co-localised SAOZ observations, by global mapping of tracers (O3, N2O and columns of O3) from Aura/MLS and Aura/OMI experiments, and by model simulations of Ertel Potential Vorticity initialised by ECMWF (European Centre for Medium-Range Weather Forecasts) data reanalyses. Satellite and ground-based observational data revealed a consistent increase of ozone in the local stratosphere by mid-April 2008. Additionally, Ozone (O3) and nitrous oxide (N2O) profiles obtained during January-May 2008 by the Microwave Lamb Sounder (MLS) aboard the Aura satellite are assimilated into MOCAGE (MOdèle de Chimie Atmosphérique à Grande Echelle), a global three-dimensional chemistry transport model of Météo-France. The assimilated total O3 values are consistent with SAOZ ground observations (within ±5%), and isentropic distributions of O3 are matching well with maps of advected potential vorticity (APV) derived from the MIMOSA model, a high-resolution advection transport model, and from ECMWF reanalysis. The studied event seems to be related to isentropic transport of air masses that took place simultaneously in the lower- and middle-stratosphere, respectively from the polar region and from tropics to the mid-latitudes. In fact, the studied ozone increase by mid April 2008 results simultaneously: (1) from an equator-ward departure of polar air masses characterised with a high-ozone layer in the lower stratosphere (nearby the 475 K isentropic level), and (2) from a reverse isentropic transport from tropics to mid- and high-latitudes in the upper stratosphere (nearby the 700 K level). The increase of ozone observed over Kerguelen from the 16-April ozonesonde profile is then attributed to a concomitant isentropic transport of ozone in two stratospheric layers: the tropical air moving southward and reaches over Kerguelen in the upper stratosphere, and the polar air passing over the same area but in the lower stratosphere.

Simultaneous measurements of ozone outside and inside cabins of two B-747 airliners and a Gates Learjet business jet

NASA Technical Reports Server (NTRS)

Perkins, P. J.; Briehl, D.

1978-01-01

Recently, passengers and crew members on long-distance commercial flights have filed complaints after suffering symptoms of ozone sickness. Studies were conducted to determine the frequency and concentration of ozone in commercial jet transports. The airliner problem with ozone prompted NASA to determine the ozone concentrations that might be encountered in the cabin of a small business jet. Simultaneous measurements of atmospheric ozone levels and ozone levels in the cabins of jet aircraft were necessary because of the wide and rapid variability of atmospheric ozone in flight. It was found that the atmospheric ozone concentrations in the case of B-747 airliners vary widely during a flight. A constant difference, or ratio, between ozone concentrations outside and inside the cabin does not exist.

Ozone studies in the Paso del Norte region

NASA Astrophysics Data System (ADS)

Becerra-Davila, Fernando

The Paso del Norte region forms the largest contiguous bi-national conglomerate on the US-Mexico border. With a combined population of around 2 million inhabitants, the Paso del Norte region is isolated, more than 500 km away from the nearest urban area of comparable size, thus making it an ideal location for air quality studies of an isolated urban environment. The meteorological conditions leading to a high ozone episode in this region, such as the historical ozone episode of June 2006, are analyzed. It is well known that stagnation and minimal winds, high temperatures, and pressure ridges over the region are conducive to high ozone episodes. In addition, the planetary boundary height is studied to understand its impact on high ozone episodes. Several studies report that ground level ozone non-attainment regulations could be caused not only by local emissions, but also by atmospheric transport. In this work the atmospheric advection of pollutants into the region is analyzed using HYSPLIT backward trajectories. Furthermore, a novel backward trajectory clustering technique is implemented for the summer of 2006. The "ozone weekend effect" (OWE) is a phenomenon by which in some geographical regions ambient ozone concentrations tend to be higher on weekends than on weekdays, despite the lower emissions of ozone precursors during those days. The observed local OWE has never previously been studied in terms of the photolysis rates of four of the main ozone precursors. In this research a novel method that allows the calculation of actinic fluxes, photolysis frequencies and photolysis rates with a high degree of accuracy and reliability has been developed. This method utilizes a combination of the experimental data available for this region in conjunction with a radiative transfer model (TUV model). Three weekend-weekday cases during summers 2006, 2009 and 2010 are studied in this work. In this research, the photolysis impact on the local OWE is studied. The results obtained from this photolysis study demonstrate that the local ground level ozone formation is not only influenced by the strong solar radiation and changing aerosol makeup, but also by other heterogeneous factors and reactions. In addition, this research provided good evidence that the ground level ozone precursor regime in El Paso during the ozone episode of June 2006 was mostly VOC-limited. Much of this estimation was derived from measurements of local ambient VOC/NOx ratios. This finding shows that at least during June 2006, the non-linear surface ozone production increased during weekends compared to workdays in a habitually VOC-limited regime. The seasonal variations of columnar ozone as measured by a Multi-filter Rotating Shadowband instrument installed at the UTEP campus are analyzed for the first time for this region and results are presented. This investigation has addressed the problem of ground-level ozone formation in the Paso del Norte region. Urban ozone is a complex problem with many aspects that are not fully understood. In this investigation, a range of techniques has been used to address the study of local surface ozone episodes with the purpose of acquiring new insights and knowledge that will help understand and remediate the diverse atmospheric pollution events that affect this bi-national region recurrently. Innovative techniques were developed and used, ranging from the use of local ambient atmospheric pollution data to the utilization of complex modeling techniques to achieve the best possible computer results. Finally, the influence of ground level ozone concentrations in admissions to hospitals for this region due to respiratory diseases is analyzed. The comprehensive results obtained in this work will help to better understand ozone formation in the Paso del Norte Region for future policy regulation implementations.

Historical Analysis and Charaterization of Ground Level Ozone for Canada and United State

NASA Astrophysics Data System (ADS)

Lin, H.; Li, H.; Auld, H.

2003-12-01

Ground-level ozone has long been recognized as an important health and ecosystem-related air quality concern in Canada and the United States. In this work we seek to understand the characteristics of ground level ozone conditions for Canada and United States to support the Ozone Annex under the Canada-U.S. Air Quality Agreement. Our analyses are based upon the data collected by Canadian National Air Pollution Surveillance (NAPS, the NAPS database has also been expanded to include U.S. EPA ground level ozone data) network. Historical ozone data from 1974 to 2002 at a total of 538 stations (253 Canadian stations and 285 U.S. stations) were statistically analyzed using several methodologies including the Canada Wide Standard (CWS). A more detailed analysis including hourly, daily, monthly, seasonally and yearly ozone concentration distributions and trends was undertaken for 54 stations.

Efficacy of Gaseous Ozone Application during Vacuum Cooling against Escherichia coli O157:H7 on Spinach Leaves as Influenced by Bacterium Population Size.

PubMed

Yesil, Mustafa; Kasler, David R; Huang, En; Yousef, Ahmed E

2017-07-01

Foodborne disease outbreaks associated with the consumption of fresh produce pose a threat to public health, decrease consumer confidence in minimally processed foods, and negatively impact the sales of these commodities. The aim of the study was to determine the influence of population size of inoculated pathogen on its inactivation by gaseous ozone treatment during vacuum cooling. Spinach leaves were spot inoculated with Escherichia coli O157:H7 at approximate initial populations of 10 8 , 10 7 , and 10 5 CFU/g. Inoculated leaves were vacuum cooled (28.5 inHg; 4°C) in a custom-made vessel and then were subjected to a gaseous ozone treatment under the following conditions: 1.5 g of ozone per kg of gas mixture, vessel pressure at 10 lb/in 2 gauge, 94 to 98% relative humidity, and 30 min of holding time at 9°C. Treatment of the leaves, having the aforementioned inocula, decreased E. coli populations by 0.2, 2.1, and 2.8 log CFU/g, respectively, compared with the inoculated untreated controls. Additionally, spinach leaves were inoculated at 1.4 × 10 3 CFU/g, which approximates natural contamination level, and the small populations remaining after ozone treatment were quantified using the most-probable-number (MPN) method. Vacuum and ozone sequential treatment decreased this E. coli O157:H7 population to <3 MPN/g (i.e., greater than 3-log reduction). Resulting log reductions were greater (P < 0.05) at the lower rather than the higher inoculum levels. In conclusion, treatment of spinach leaves with gaseous ozone is effective against pathogen loads comparable to those found in naturally contaminated fresh produce, but efficacy decreases as inoculum level increases.

AMPK activation by peri-sciatic nerve administration of ozone attenuates CCI-induced neuropathic pain in rats.

PubMed

Lu, Lijuan; Pan, Cailong; Chen, Lu; Hu, Liang; Wang, Chaoyu; Han, Yuan; Yang, Yanjing; Cheng, Zhixiang; Liu, Wen-Tao

2017-04-01

Neuropathic pain is a debilitating clinical condition with few efficacious treatments, warranting development of novel therapeutics. Ozone is widely used as an alternative therapy for many different pain conditions, with exact mechanisms still elusive. In this study, we found that a single peri-sciatic nerve injection of ozone decreased mechanical allodynia and thermal hyperalgesia, and normalized the phosphorylation of protein kinase C γ, N-methyl-D-aspartate receptor, and extracellular signal-regulated kinase in a chronic constriction injury (CCI) model in rat sciatic nerve. Meanwhile, ozone significantly suppressed CCI-induced activation of spinal microglia. More importantly, the anti-nociceptive effect of ozone depended on the activation of 5'-adenosine monophosphate (AMP)-activated protein kinase (AMPK), which was proved by the fact that the phosphorylated AMPK level increased during the ozone therapy and AMPK antagonist abolished the effect of ozone in vivo and in vitro. In addition, direct injection of AMPK agonist could replicate the anti-nociceptive effect of ozone in CCI rats. In conclusion, our observations indicate that peri-sciatic nerve injection of ozone activates AMPK to attenuate CCI-induced neuropathic pain. © The Author (2016). Published by Oxford University Press on behalf of Journal of Molecular Cell Biology, IBCB, SIBS, CAS. All rights reserved.

Improved hurricane forecasting from a variational bogus and ozone data assimilation (BODA) scheme: case study

NASA Astrophysics Data System (ADS)

Liu, Yin; Zhang, Wei

2016-12-01

This study develops a proper way to incorporate Atmospheric Infrared Sounder (AIRS) ozone data into the bogus data assimilation (BDA) initialization scheme for improving hurricane prediction. First, the observation operator at some model levels with the highest correlation coefficients is established to assimilate AIRS ozone data based on the correlation between total column ozone and potential vorticity (PV) ranging from 400 to 50 hPa level. Second, AIRS ozone data act as an augmentation to a BDA procedure using a four-dimensional variational (4D-Var) data assimilation system. Case studies of several hurricanes are performed to demonstrate the effectiveness of the bogus and ozone data assimilation (BODA) scheme. The statistical result indicates that assimilating AIRS ozone data at 4, 5, or 6 model levels can produce a significant improvement in hurricane track and intensity prediction, with reasonable computation time for the hurricane initialization. Moreover, a detailed analysis of how BODA scheme affects hurricane prediction is conducted for Hurricane Earl (2010). It is found that the new scheme developed in this study generates significant adjustments in the initial conditions (ICs) from the lower levels to the upper levels, compared with the BDA scheme. With the BODA scheme, hurricane development is found to be much more sensitive to the number of ozone data assimilation levels. In particular, the experiment with the assimilation of AIRS ozone data at proper number of model levels shows great capabilities in reproducing the intensity and intensity changes of Hurricane Earl, as well as improve the track prediction. These results suggest that AIRS ozone data convey valuable meteorological information in the upper troposphere, which can be assimilated into a numerical model to improve hurricane initialization when the low-level bogus data are included.

Antarctic Ozone Hole, 2000

NASA Technical Reports Server (NTRS)

2002-01-01

Each spring the ozone layer over Antarctica nearly disappears, forming a 'hole' over the entire continent. The hole is created by the interaction of some man-made chemicals-freon, for example-with Antarctica's unique weather patterns and extremely cold temperatures. Ozone in the stratosphere absorbs ultraviolet radiation from the sun, thereby protecting living things. Since the ozone hole was discovered many of the chemicals that destroy ozone have been banned, but they will remain in the atmosphere for decades. In 2000, the ozone hole grew quicker than usual and exceptionally large. By the first week in September the hole was the largest ever-11.4 million square miles. The top image shows the average total column ozone values over Antarctica for September 2000. (Total column ozone is the amount of ozone from the ground to the top of the atmosphere. A relatively typical measurement of 300 Dobson Units is equivalent to a layer of ozone 0.12 inches thick on the Earth's surface. Levels below 220 Dobson Units are considered to be significant ozone depletion.) The record-breaking hole is likely the result of lower than average ozone levels during the Antarctic fall and winter, and exceptionally cold temperatures. In October, however (bottom image), the hole shrank dramatically, much more quickly than usual. By the end of October, the hole was only one-third of it's previous size. In a typical year, the ozone hole does not collapse until the end of November. NASA scientists were surprised by this early shrinking and speculate it is related to the region's weather. Global ozone levels are measured by the Total Ozone Mapping Spectrometer (TOMS). For more information about ozone, read the Earth Observatory's ozone fact sheet, view global ozone data and see these ozone images. Images by Greg Shirah, NASA GSFC Scientific Visualization Studio.

Effects of 10% biofuel substitution on ground level ozone formation in Bangkok, Thailand

NASA Astrophysics Data System (ADS)

Milt, Austin; Milano, Aaron; Garivait, Savitri; Kamens, Richard

2009-12-01

The Thai Government's search for alternatives to imported petroleum led to the consideration of mandating 10% biofuel blends (biodiesel and gasohol) by 2012. Concerns over the effects of biofuel combustion on ground level ozone formation in relation to their conventional counterparts need addressing. Ozone formation in Bangkok is explored using a trajectory box model. The model is compared against O 3, NO, and NO 2 time concentration data from air monitoring stations operated by the Thai Pollution Control Department. Four high ozone days in 2006 were selected for modeling. Both the traditional trajectory approach and a citywide average approach were used. The model performs well with both approaches but slightly better with the citywide average. Highly uncertain and missing data are derived within realistic bounds using a genetic algorithm optimization. It was found that 10% biofuel substitution will lead to as much as a 16 ppb peak O 3 increase on these four days compared to a 48 ppb increase due to the predicted vehicle fleet size increase between 2006 and 2012. The approach also suggests that when detailed meteorological data is not available to run three dimensional airshed models, and if the air is stagnant or predominately remains over an urban area during the day, that a simple low cost trajectory analysis of O 3 formation may be applicable.

Secondary organic aerosol from ozone-initiated reactions with terpene-rich household products

NASA Astrophysics Data System (ADS)

Coleman, Beverly K.; Lunden, Melissa M.; Destaillats, Hugo; Nazaroff, William W.

We analyzed secondary organic aerosol (SOA) data from a series of small-chamber experiments in which terpene-rich vapors from household products were combined with ozone under conditions analogous to product use indoors. Reagents were introduced into a continuously ventilated 198 L chamber at steady rates. Consistently, at the time of ozone introduction, nucleation occurred exhibiting similar behavior to atmospheric events. The initial nucleation burst and growth was followed by a period in which approximately stable particle levels were established, reflecting a balance between new particle formation, condensational growth, and removal by ventilation. Airborne particles were measured with a scanning mobility particle sizer (SMPS, 10-400 nm) in every experiment and with an optical particle counter (OPC, 0.1-2.0 μm) in a subset. Parameters for a three-mode lognormal fit to the size distribution at steady state were determined for each experiment. Increasing the supply ozone level increased the steady-state mass concentration and yield of SOA from each product tested. Decreasing the air-exchange rate increased the yield. The steady-state fine-particle mass concentration (PM 1.1) ranged from 10 to >300 μg m -3 and yields ranged from 5% to 37%. Steady-state nucleation rates and SOA mass formation rates were ˜10 cm -3 s -1 and ˜10 μg m -3 min -1, respectively.

Secondary organic aerosol from ozone-initiated reactions with terpene-rich household products

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coleman, Beverly; Coleman, Beverly K.; Lunden, Melissa M.

2008-01-01

We analyzed secondary organic aerosol (SOA) data from a series of small-chamber experiments in which terpene-rich vapors from household products were combined with ozone under conditions analogous to product use indoors. Reagents were introduced into a continuously ventilated 198 L chamber at steady rates. Consistently, at the time of ozone introduction, nucleation occurred exhibiting behavior similar to atmospheric events. The initial nucleation burst and growth was followed by a period in which approximately stable particle levels were established reflecting a balance between new particle formation, condensational growth, and removal by ventilation. Airborne particles were measured with a scanning mobility particlemore » sizer (SMPS, 10 to 400 nm) in every experiment and with an optical particle counter (OPC, 0.1 to 2.0 ?m) in a subset. Parameters for a three-mode lognormal fit to the size distribution at steady state were determined for each experiment. Increasing the supply ozone level increased the steady-state mass concentration and yield of SOA from each product tested. Decreasing the air-exchange rate increased the yield. The steady-state fine-particle mass concentration (PM1.1) ranged from 10 to> 300 mu g m-3 and yields ranged from 5percent to 37percent. Steady-state nucleation rates and SOA mass formation rates were on the order of 10 cm-3 s-1 and 10 mu g m-3 min-1, respectively.« less

A Lagrangian analysis of mid-latitude stratospheric ozone variability and long-term trends.

NASA Astrophysics Data System (ADS)

Koch, G.; Wernli, H.; Staehelin, J.; Peter, T.

2002-05-01

A systematic Lagrangian investigation is performed of wintertime high-resolution stratospheric ozone soundings at Payerne, Switzerland, from January 1970 to March 2001. For every ozone sounding, 10-day backward trajectories have been calculated on 16 isentropic levels using NCEP reanalysis data. Both the minimum/maximum latitude and potential vorticity (PV) averaged along the trajectories are used as indicators of the air parcels' ``origin''. The importance of transport for the understandin g of single ozone profiles is confirmed by a statistical analysis which shows that negative/positive ozone deviations gener ally coincide with transport from regions with climatologically low/high ozone values. The stable relationship between PV and ozone for the 32 year period indicates either no direct chemical impact or no temporal change of this impact. In the upper layer the PV-ozone relationship changes significantly after 1987 and a separate trend analysis for air masses transported from the polar, midlatitude and subtropical regions shows negative ozone trends in all three categories (with a maximum for the polar region). This is not direct evidence for, but would be in agreement with, an increased chemical ozone depletion in the Arctic since the late 1980s. The reasons for the negative trend in the mid-stratospheric air masses with subtropical origin that are in qualitative agreement with recent satellite observations are presently unknown.

Growth and recovery of zebrafish embryos after developmental exposure to raw and ozonated oil sands process-affected water.

PubMed

Lyons, Danielle D; Morrison, Christie; Philibert, Danielle A; Gamal El-Din, Mohamed; Tierney, Keith B

2018-05-07

Due to the increasing volume of oil sands process-affect water (OSPW) and its toxicity to aquatic organisms, it is important to fully understand its effects and study remediation processes that will enable its release to the environment. Ozone treatment is currently being considered as a tool to expedite remediation, as it is known to degrade toxic organic compounds present in OSPW. In this study, we aimed to measure the effects of OSPW exposure on the growth, development and recovery of zebrafish (Danio rerio) embryos. We also used ozone-treated OSPW to determine whether ozonation negated any effects of raw OSPW exposure. As biomarkers of exposure, we assessed the expression of genes involved in neurodevelopment (ngn1, neuroD), estrogenicity (vtg), oxidative stress (sod1), and biotransformation (cyp1a, cyp1b). Our study found that exposure to both raw and ozonated OSPW did not impair growth of zebrafish embryos, however, otoliths of exposed embryos were smaller than those of control embryos. The expression levels of both cyp1a and cyp1b were induced by raw OSPW exposure. However, after the exposure period, expression levels of these genes returned to control levels within two days of residence in clean water. We found no changes in the expression levels of ngn1, neuroD and vtg genes with exposure to treated or untreated OSPW. Overall, our study found that raw OSPW exposure did not have many negative effects on zebrafish embryos and embryos appeared to recover relatively quickly after exposure ended. Furthermore, ozone treatment decreased the induction of cyp1a and cyp1b. Copyright © 2018 Elsevier Ltd. All rights reserved.

Ozone photochemical production in urban Shanghai, China: Analysis based on ground level observations

NASA Astrophysics Data System (ADS)

Ran, Liang; Zhao, Chunsheng; Geng, Fuhai; Tie, Xuexi; Tang, Xu; Peng, Li; Zhou, Guangqiang; Yu, Qiong; Xu, Jianmin; Guenther, Alex

2009-08-01

Ozone and its precursors were measured from 15 June 2006 to 14 June 2007 at an urban site in Shanghai and used to characterize photochemical oxidant production in this region. During the observation period, ozone displays a seasonal variation with a maximum in spring. Observed nitrogen oxides (NOx) and carbon monoxide (CO) reached a maximum in winter and a minimum in summer. NOx and CO has a similar double-peak diurnal cycle, implying that they are largely of motor vehicle origin. Total nonmethane organic compounds (NMOC) concentrations averaged over the morning, and the 24-hour periods have a large day-to-day variation with no apparent seasonal cycle. Aromatics play a dominant role in contributing to total NMOC reactivity and ozone-forming potential. Anthropogenic NMOC of diverse sources are major components of total NMOC and consist mainly of moderate and low reactivity species. In contrast, relatively low levels of biogenic NMOC concentrations were observed in urban Shanghai. The early morning NMOC/NOx ratios are typically below 8:1 with an average of around 4:1, indicating that the sampling location is situated in a NMOC-limited regime. Model simulations confirm that potential photochemical ozone production in Shanghai is NMOC-sensitive. It is presently difficult to predict the impact of future human activities, such as the increase of automobiles and vegetation-covered landscapes and the reduction of aerosol on ozone pollution in the fast developing megacities of China, and additional studies are needed to better understand the highly nonlinear ozone problem.

Impact of near-surface atmospheric composition on ozone formation in Russia

NASA Astrophysics Data System (ADS)

Berezina, Elena; Moiseenko, Konstantin; Skorokhod, Andrey; Belikov, Igor; Pankratova, Natalia; Elansky, Nikolai

2017-04-01

One of the consequences of the human impact on the atmosphere is increasing in tropospheric ozone concentration, with the highest ozone level being observed in industrially developed and highly populated regions of the world. In these regions, main anthropogenic sources of carbon monoxide (CO), methane (CH4) and volatile organic compounds (VOCs) are concentrated. The oxidation of these compounds, when interacting with hydroxyl and nitrogen oxides at rather high temperature and sunlight, leads to ozone formation. CO and CH4 are slowly oxidized in the atmosphere and cause an increase in global and regional background ozone. However, the oxidation of some VOCs occurs during daylight hours and is accompanied by an increase in ozone concentration near VOCs sources, particularly in urban and industrial areas. The contribution of biogenic VOCs to ozone generation is estimated to be from 40 to 70% of the total contribution of all chemical ozone precursors in the troposphere [1], with isoprene playing the main role in ozone formation [2]. The impact of aromatic hydrocarbons to ozone formation is reported to be about 40% of the total ozone generation from the oxidation of anthropogenic VOCs [3]. In this study, the results of VOCs measurements (isoprene, benzene, toluene, phenol, styrene, xylene and propilbenzene) by proton mass spectrometry in different regions of Russia along the Trans-Siberian railway from Moscow to Vladivostok from TROICA-12 campaign on a mobile laboratory in summer 2008 are analyzed. It is shown that the TROICA-12 measurements were carried out mostly in moderately polluted (2≤NOx<20 ppb) environment ( 78% of measurements) with the remaining part of the measurements divided between weakly polluted (NOx≤2 ppb) and highly polluted (NOx>20 ppb) conditions ( 20 and 2% of measurements, correspondingly). The lower troposphere chemical regime in the campaign is found to be mainly NOx sensitive, both in rural and urban environments, with typical morning NMHC/NOx ratios being well above 20. Hence, ozone production rates are expected to be controlled by regional NOx emissions and their complex interplay with both natural and anthropogenic sources of VOCs. The quantitative contribution of aromatic VOCs to ozone formation in urban areas and in Russian regions along the railway is estimated. The greatest impact of aromatic VOCs to ozone formation (up to 7.5 ppb of O3) is obtained in the large cities along the Trans-Siberian Railway, with the highest concentrations of aromatic VOCs (1-1.7 ppb) and nitrogen oxides (> 20 ppb) being observed. The results show a significant contribution of anthropogenic emissions of VOCs to the photochemical ozone generation (30-50%) in the large cities along the Trans-Siberian railway in hot and dry weather conditions against natural isoprene emissions determining the regional balance of ground-level ozone in summer. This study was supported by the Russian Science Foundation (grant no. 14-47-00049) and by the Russian Foundation for Basic Research (grant no. 16-35-00158). References: 1. Xie, X., Shao, M., Liu, Y., Lu, S., Chang, C. C., and Chen, Z. M. // Atmos. Environ., 2008, 42, pp. 6000-6010. 2. Guenther, A., Geron, C., Pierce, T., Lamb, B., Harley, P., Fall, R. // Atmospheric Environment, 2000, 34, pp. 2205-2230. 3. Dreyfus, G. B., Schade G. W., Goldstein A. H. // J. Geophys. Res., 2002, 107(D19): 4365, doi:10.1029/2001JD001490.

Changes in tropospheric composition and air quality due to stratospheric ozone depletion and climate change.

PubMed

Wilson, S R; Solomon, K R; Tang, X

2007-03-01

It is well-understood that reductions in air quality play a significant role in both environmental and human health. Interactions between ozone depletion and global climate change will significantly alter atmospheric chemistry which, in turn, will cause changes in concentrations of natural and human-made gases and aerosols. Models predict that tropospheric ozone near the surface will increase globally by up to 10 to 30 ppbv (33 to 100% increase) during the period 2000 to 2100. With the increase in the amount of the stratospheric ozone, increased transport from the stratosphere to the troposphere will result in different responses in polluted and unpolluted areas. In contrast, global changes in tropospheric hydroxyl radical (OH) are not predicted to be large, except where influenced by the presence of oxidizable organic matter, such as from large-scale forest fires. Recent measurements in a relatively clean location over 5 years showed that OH concentrations can be predicted by the intensity of solar ultraviolet radiation. If this relationship is confirmed by further observations, this approach could be used to simplify assessments of air quality. Analysis of surface-level ozone observations in Antarctica suggests that there has been a significant change in the chemistry of the boundary layer of the atmosphere in this region as a result of stratospheric ozone depletion. The oxidation potential of the Antarctic boundary layer is estimated to be greater now than before the development of the ozone hole. Recent modeling studies have suggested that iodine and iodine-containing substances from natural sources, such as the ocean, may increase stratospheric ozone depletion significantly in polar regions during spring. Given the uncertainty of the fate of iodine in the stratosphere, the results may also be relevant for stratospheric ozone depletion and measurements of the influence of these substances on ozone depletion should be considered in the future. In agreement with known usage and atmospheric loss processes, tropospheric concentrations of HFC-134a, the main human-made source of trifluoroacetic acid (TFA), is increasing rapidly. As HFC-134a is a potent greenhouse gas, this increasing concentration has implications for climate change. However, the risks to humans and the environment from substances, such as TFA, produced by atmospheric degradation of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) are considered minimal. Perfluoropolyethers, commonly used as industrial heat transfer fluids and proposed as chlorohydrofluorocarbon (CHFC) substitutes, show great stability to chemical degradation in the atmosphere. These substances have been suggested as substitutes for CHFCs but, as they are very persistent in the atmosphere, they may be important contributors to global warming. It is not known whether these substances will contribute significantly to global warming and its interaction with ozone depletion but they should be considered for further evaluation.

Meteorological detrending of primary and secondary pollutant concentrations: Method application and evaluation using long-term (2000-2012) data in Atlanta

NASA Astrophysics Data System (ADS)

Henneman, Lucas R. F.; Holmes, Heather A.; Mulholland, James A.; Russell, Armistead G.

2015-10-01

The effectiveness of air pollution regulations and controls are evaluated based on measured air pollutant concentrations. Air pollution levels, however, are highly sensitive to both emissions and meteorological fluctuations. Therefore, an assessment of the change in air pollutant levels due to emissions controls must account for these meteorological fluctuations. Two empirical methods to quantify the impact of meteorology on pollutant levels are discussed and applied to the 13-year time period between 2000 and 2012 in Atlanta, GA. The methods employ Kolmogorov-Zurbenko filters and linear regressions to detrended pollutant signals into long-term, seasonal, weekly, short-term, and white-noise components. The methods differ in how changes in weekly and holiday emissions are accounted for. Both can provide meteorological adjustments on a daily basis for future use in acute health analyses. The meteorological impact on daily signals of ozone, NOx, CO, SO2, PM2.5, and PM species are quantified. Analyses show that the substantial decreases in seasonal averages of NOx and SO2 correspond with controls implemented in the metropolitan Atlanta area. Detrending allows for the impacts of some controls to be observed with averaging times of as little as 3 months. Annual average concentrations of NOx, SO2, and CO have all fallen by at least 50% since 2000. Reductions in NOx levels, however, do not lead to uniform reductions in ozone. While average detrended summer average maximum daily average 8 h ozone (MDA8h O3) levels fell by 4% (2.2 ± 2 ppb) between 2000 and 2012, winter averages have increased by 12% (3.8 ± 1.4 ppb), providing further evidence that high ozone levels are NOx-limited and lower ozone concentrations are NOx-inhibited. High ozone days (with MDA8h O3 greater than 60 ppb) decreased both in number and in magnitude over the study period.

Outdoor air pollutants and patient health.

PubMed

Laumbach, Robert J

2010-01-15

Almost 160 million persons live in areas of the United States that exceed federal health-based air pollution standards. The two air pollutants that most commonly exceed standards are ozone and particulate matter. Ozone and particulate matter can harm anyone if levels are sufficiently elevated, but health risk from air pollution is greatest among vulnerable populations. Both ozone and particulate matter can cause pulmonary inflammation, decreased lung function, and exacerbation of asthma and chronic obstructive pulmonary disease. Particulate matter is also strongly associated with increased cardiovascular morbidity and mortality. Children, older adults, and other vulnerable persons may be sensitive to lower levels of air pollution. Persons who are aware of local air pollution levels, reported daily by the U.S. Environmental Protection Agency as the Air Quality Index, can take action to reduce exposure. These actions include simple measures to limit exertion and time spent outdoors when air pollution levels are highest, and to reduce the infiltration of outdoor air pollutants into indoor spaces.

Maternal exposure to ozone and PM{sub 2.5} and the prevalence of orofacial clefts in four U.S. states

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Ying, E-mail: yzhou2@cdc.gov

Background: While there is some evidence that maternal exposure to ambient air pollution is associated with orofacial clefts in offspring, the epidemiologic studies have been largely equivocal. We evaluated whether maternal exposure to elevated county-level ambient fine particulate matter with aerodynamic diameter ≤2.5 µm (PM{sub 2.5}) and ozone during early gestation was associated with a higher prevalence of orofacial clefts. Methods: Birth data consisting of 4.7 million births from 2001 to 2007 were obtained from National Birth Defects Prevention Network for four states — Arizona, Florida, New York (excluding New York City), and Texas. The air pollution exposure assessment formore » gestational weeks 5–10 was based on county-level average concentrations of PM{sub 2.5} and ozone data generated using a Bayesian fusion model available through CDC's Environmental Public Health Tracking Network. Two outcomes were analyzed separately: cleft lip with or without cleft palate, cleft palate alone. In logistic regression analyses, we adjusted for factors that were suspected confounders or modifiers of the association between the prevalence of orofacial clefts and air pollution, i.e., infant sex, race-ethnicity, maternal education, smoking status during pregnancy, whether this was mother's first baby, maternal age. Results: Each 10 µg/m{sup 3} increase in PM{sub 2.5} concentration was significantly associated with cleft palate alone (OR =1.43, 95% CI: 1.11–1.86). There was no significant association between PM{sub 2.5} concentration and cleft lip with or without cleft palate. No associations were observed between ozone exposure and the two outcomes of orofacial clefts. Conclusions: Our study suggests that PM{sub 2.5} significantly increased the risk of cleft palate alone, but did not change the incidence of cleft lip with or without palate. Ozone levels did not correlate with incidence of orofacial clefts. - Highlights: • This is a large study with about 4.7 million births and 7000 orofacial cleft cases. • PM{sub 2.5} significantly increased the risk of cleft palate alone. • PM{sub 2.5} did not change the incidence of cleft lip with or without palate. • Ozone levels did not correlate with incidence of orofacial clefts.« less

Ozone and Ozone By-Products in the Cabins of Commercial Aircraft

PubMed Central

Weisel, Clifford; Weschler, Charles J.; Mohan, Kris; Vallarino, Jose; Spengler, John D.

2013-01-01

The aircraft cabin represents a unique indoor environment due to its high surface-to-volume ratio, high occupant density and the potential for high ozone concentrations at cruising altitudes. Ozone was continuously measured and air was sampled on sorbent traps, targeting carbonyl compounds, on 52 transcontinental U.S. or international flights between 2008 and 2010. The sampling was predominantly on planes that did not have ozone scrubbers (catalytic converters). Peak ozone levels on aircraft without catalytic convertors exceeded 100 ppb, with some flights having periods of more than an hour when the ozone levels were > 75ppb. Ozone was greatly reduced on relatively new aircraft with catalytic convertors, but ozone levels on two flights whose aircraft had older convertors were similar to those on planes without catalytic convertors. Hexanal, heptanal, octanal, nonanal, decanal and 6-methyl-5-hepten-2-one (6-MHO) were detected in the aircraft cabin at sub- to low ppb levels. Linear regression models that included the log transformed mean ozone concentration, percent occupancy and plane type were statistically significant and explained between 18 and 25% of the variance in the mixing ratio of these carbonyls. Occupancy was also a significant factor for 6-MHO, but not the linear aldehydes, consistent with 6-MHO’s formation from the reaction between ozone and squalene, which is present in human skin oils. PMID:23517299

Extreme value modeling for the analysis and prediction of time series of extreme tropospheric ozone levels: a case study.

PubMed

Escarela, Gabriel

2012-06-01

The occurrence of high concentrations of tropospheric ozone is considered as one of the most important issues of air management programs. The prediction of dangerous ozone levels for the public health and the environment, along with the assessment of air quality control programs aimed at reducing their severity, is of considerable interest to the scientific community and to policy makers. The chemical mechanisms of tropospheric ozone formation are complex, and highly variable meteorological conditions contribute additionally to difficulties in accurate study and prediction of high levels of ozone. Statistical methods offer an effective approach to understand the problem and eventually improve the ability to predict maximum levels of ozone. In this paper an extreme value model is developed to study data sets that consist of periodically collected maxima of tropospheric ozone concentrations and meteorological variables. The methods are applied to daily tropospheric ozone maxima in Guadalajara City, Mexico, for the period January 1997 to December 2006. The model adjusts the daily rate of change in ozone for concurrent impacts of seasonality and present and past meteorological conditions, which include surface temperature, wind speed, wind direction, relative humidity, and ozone. The results indicate that trend, annual effects, and key meteorological variables along with some interactions explain the variation in daily ozone maxima. Prediction performance assessments yield reasonably good results.

Distribution and urban-suburban differences in ground-level ozone and its precursors over Shenyang, China

NASA Astrophysics Data System (ADS)

Liu, Ningwei; Ren, Wanhui; Li, Xiaolan; Ma, Xiaogang; Zhang, Yunhai; Li, Bingkun

2018-03-01

Hourly mixing ratio data of ground-level ozone and its main precursors at ambient air quality monitoring sites in Shenyang during 2013-2015 were used to survey spatiotemporal variations in ozone. Then, the transport of ozone and its precursors among urban, suburban, and rural sites was examined. The correlations between ozone and some key meteorological factors were also investigated. Ozone and O x mixing ratios in Shenyang were higher during warm seasons and lower during cold ones, while ozone precursors followed the opposite cycle. Ozone mixing ratios reached maximum and minimum values in the afternoon and morning, respectively, reflecting the significant influence of photochemical production during daytime and depletion via titration during nighttime. Compared to those in downtown Shenyang, ozone mixing ratios were higher and the occurrence of peak values were later in suburban and rural areas downwind of the prevailing wind. The differences were most significant in summer, when the ozone mixing ratios at one suburban downwind site reached a maximum value of 35.6 ppb higher than those at the downtown site. This suggests that photochemical production processes were significant during the transport of ozone precursors, particularly in warm seasons with sufficient sunlight. Temperature, total radiation, and wind speed all displayed positive correlations with ozone concentration, reflecting their important role in accelerating ozone formation. Generally, the correlations between ozone and meteorological factors were slightly stronger at suburban sites than in urban areas, indicating that ozone levels in suburban areas were more sensitive to these meteorological factors.

Vitamin D Synthesis by UV Radiation: the Importance of Ozone Monitoring

NASA Astrophysics Data System (ADS)

Olds, W. J.; Moore, M. R.; Kimlin, M. G.

2006-12-01

The majority of humans rely on incidental sun exposure to maintain vitamin D sufficiency. Depending on where thresholds of vitamin D "sufficiency" are defined, it was recently stated that up to one billion people worldwide have suboptimal vitamin D levels (Bouillon, R., University of Leuven). Even in sunny southeast Queensland, the world's skin cancer capital, a 2006 study uncovered deficiency rates of up to 78% (at a threshold of 75 nmol/L of circulating 25-hydroxyvitamin D). Vitamin D regulates calcium absorption and inadequate levels are proven to result in osteomalacia, osteoporosis, rickets, bone pain and general skeletal weakness. Recent evidence also suggests vitamin D plays a preventative role in autoimmune diseases including numerous cancers, diabetes, schizophrenia, coronary heart disease, depression and other disorders. The most promising means of alleviating the worldwide burden of vitamin D deficiency seems to be by increased UV exposure. However, a much more mature understanding of UV exposures encountered in everyday life is required. This understanding is fundamentally founded in geophysics. UV exposures are strongly influenced by season/time of year, time of day, climate, location, pollution, aerosols and, importantly, ozone. In this work, we use computer simulations to obtain daily totals of vitamin D producing UV at numerous latitudes during one year. The ozone concentration is varied from 260 DU to 360 DU to determine the role of ozone variability on the ambient levels of vitamin D UV. Vitamin D synthesis is highly dependent on UVB. In our results, we demonstrate that this has important implications. Namely, vitamin D is strongly affected by ozone variability, since ozone filters UVB more strongly than UVA. Moreover, since erythema (sunburn) can occur at UVA wavelengths, ozone variation will more strongly affect vitamin D synthesis than erythema. Our results highlight that ozone monitoring is essential for understanding appropriate UV exposures for vitamin D health. We finally discuss implications for population health and how geophysics continues to play a vital role in addressing the widespread dilemma of vitamin D deficiency.

Extracellular polymers of ozonized waste activated sludge.

PubMed

Liu, J C; Lee, C H; Lai, J Y; Wang, K C; Hsu, Y C; Chang, B V

2001-01-01

Effect of ozonation on characteristics of waste activated sludge was investigated in the current study. Concentrations of cell-bound extracellular polymers (washed ECPs) did not change much upon ozonation, whereas the sum of cell-bound and soluble extracellular polymers (unwashed ECPs) increased with increasing ozone dose. Washed ECPs in original sludge as divided by molecular weight distribution was 39% < 1,000 Da (low MW), 30% from 1,000 to 10,000 Da (medium MW), and 31% > 10,000 Da (high MW). It was observed that the low-MW fraction decreased, and the high-MW fraction increased in ozonized sludge. The unwashed ECPs were characterized as 44% in low MW, 30% in medium MW, and 26% in high MW. Both low-MW and medium-MW fractions of unwashed ECPs decreased while high-MW fraction increased in ozonized sludge. The dewaterability of ozonized sludge, assessed by capillary suction time (CST) and specific resistance to filtration (SRF), deteriorated with ozone dose. The optimal dose of cationic polyelectrolyte increased with increasing ozone dose. The production rate and the accumulated amount of methane gas of ozonized sludge were also higher.

Analysis of 1970-1995 Trends in Tropospheric Ozone at Northern Hemisphere Midlatitudes with the GEOS-CHEM Model

NASA Technical Reports Server (NTRS)

Fusco, Andrew C.; Logan, Jennifer A.

2004-01-01

I ] The causes of trends in tropospheric ozone at Northern Hemisphere midlatitudes from 1970 to 1995 are investigated with the GEOS-CHEM model, a global three-dimensional model of the troposphere driven by assimilated meteorological observations from the Goddard Earth Observing System (GEOS). This model is used to investigate the sensitivity of tropospheric ozone with respect to (1) changes in the anthropogenic emission of nitrogen oxides and nonmethane hydrocarbons, (2) increases in methane concentrations, (3) variations in the stratospheric source of ozone, (4) changes in solar radiation resulting from stratospheric ozone depletion, and ( 5 ) increases in tropospheric temperatures. Model results indicate that local increases in NO, emissions have caused most of the increases seen in lower tropospheric ozone over Europe and Japan. Increases in methane are responsible for roughly one fifth of the anthropogenically induced increase in tropospheric ozone at northern midlatitudes. However, changes in ozone precursors do not adequately explain either the spatial differences in observed ozone trends across midlatitudes or the observed decreases in ozone over Canada throughout the troposphere. We argue that ozone depletion in the lowermost stratosphere is likely to have reduced the stratospheric source by as much as 30% from the early 1970s to the mid 1990s. Model simulations that account for such a reduction along with reported changes in anthropogenic emissions show steep declines of ozone in the upper troposphere and variable increases in the lower troposphere that are more consistent with observations. Differential temperature trends in summer between North America and Europe may account for at least some of the remaining spatial variation in tropospheric ozone trends. Increases in ultraviolet (UV) radiation due to stratospheric ozone depletion do not appear to significantly reduce tropospheric ozone, except at midlatitudes in the Southern Hemisphere following the breakup of the ozone hole.

Antarctic Ozone Hole on September 17, 2001

NASA Technical Reports Server (NTRS)

2002-01-01

Satellite data show the area of this year's Antarctic ozone hole peaked at about 26 million square kilometers-roughly the size of North America-making the hole similar in size to those of the past three years, according to scientists from NASA and the National Oceanic and Atmospheric Administration (NOAA). Researchers have observed a leveling-off of the hole size and predict a slow recovery. Over the past several years the annual ozone hole over Antarctica has remained about the same in both its size and in the thickness of the ozone layer. 'This is consistent with human-produced chlorine compounds that destroy ozone reaching their peak concentrations in the atmosphere, leveling off, and now beginning a very slow decline,' said Samuel Oltmans of NOAA's Climate Monitoring and Diagnostics Laboratory, Boulder, Colo. In the near future-barring unusual events such as explosive volcanic eruptions-the severity of the ozone hole will likely remain similar to what has been seen in recent years, with year-to-year differences associated with meteorological variability. Over the longer term (30-50 years) the severity of the ozone hole in Antarctica is expected to decrease as chlorine levels in the atmosphere decline. The image above shows ozone levels on Spetember 17, 2001-the lowest levels observed this year. Dark blue colors correspond to the thinnest ozone, while light blue, green, and yellow pixels indicate progressively thicker ozone. For more information read: 2001 Ozone Hole About the Same Size as Past Three Years. Image courtesy Greg Shirah, GSFC Scientific Visualization Studio, based on data from the TOMS science team

Improvement of the basic knowledge of the climatology of the vertical ozone layer by enhanced balloon sounding

NASA Technical Reports Server (NTRS)

Attmannspacher, W.; Hartmannsgrubber, R.; Lang, P.

1984-01-01

Balloon sounding of the ozone in the Earth atmosphere was performed in order to determine the natural behavior of ozone and its recognizable deviations. The importance of ozone in the Earth atmosphere and the orographic situation of observatories and ozone sounding statistics since 1966 are explained. The physical processes governing the total amount of ozone, and the behavior of stratospheric ozone are described. Measurements in the upper stratosphere show a decrease of the ozone partial pressure above 26 km altitude since 1977. The behavior of tropospheric ozone is discussed. Data since 1977 show increasing ozone values in the troposphere, up to 50% to 70%. This increase is independent of the solar radiation intensity and the reinforced transport of stratospheric ozone into the troposphere. The increase in the troposphere cannot compensate the stratospheric decrease.

Statistical analysis of stratospheric temperature and ozone profile data for trends and model comparison

NASA Technical Reports Server (NTRS)

Tiao, G. C.

1992-01-01

Work performed during the project period July 1, 1990 to June 30, 1992 on the statistical analysis of stratospheric temperature data, rawinsonde temperature data, and ozone profile data for the detection of trends is described. Our principal topics of research are trend analysis of NOAA stratospheric temperature data over the period 1978-1989; trend analysis of rawinsonde temperature data for the period 1964-1988; trend analysis of Umkehr ozone profile data for the period 1977-1991; and comparison of observed ozone and temperature trends in the lower stratosphere. Analysis of NOAA stratospheric temperature data indicates the existence of large negative trends at 0.4 mb level, with magnitudes increasing with latitudes away from the equator. Trend analysis of rawinsonde temperature data over 184 stations shows significant positive trends about 0.2 C per decade at surface to 500 mb range, decreasing to negative trends about -0.3 C at 100 to 50 mb range, and increasing slightly at 30 mb level. There is little evidence of seasonal variation in trends. Analysis of Umkehr ozone data for 12 northern hemispheric stations shows significant negative trends about -.5 percent per year in Umkehr layers 7-9 and layer 3, but somewhat less negative trends in layers 4-6. There is no pronounced seasonal variation in trends, especially in layers 4-9. A comparison was made of empirical temperature trends from rawinsonde data in the lower stratosphere with temperature changes determined from a one-dimensional radiative transfer calculation that prescribed a given ozone change over the altitude region, surface to 50 km, obtained from trend analysis of ozonsonde and Umkehr profile data. The empirical and calculated temperature trends are found in substantive agreement in profile shape and magnitude.

Recolonization by heterotrophic bacteria after UV irradiation or ozonation of seawater; a simulation of ballast water treatment.

PubMed

Hess-Erga, Ole-Kristian; Blomvågnes-Bakke, Bente; Vadstein, Olav

2010-10-01

Transport of ballast water with ships represents a risk for introduction of foreign species. If ballast water is treated during uptake, there will be a recolonization of the ballast water by heterotrophic bacteria during transport. We investigated survival and succession of heterotrophic bacteria after disinfection of seawater in the laboratory, representing a model system of ballast water treatment and transport. The seawater was exposed to ultraviolet (UV) irradiation, ozone (2 doses) or no treatment, incubated for 16 days and examined with culture-dependent and -independent methods. The number of colony-forming units (CFU) was reduced below the detection level after disinfection with UV and high ozone dose (700 mV), and 1% of the initial level for the low ozone dose (400 mV). After less than 3 days, the CFU was back or above the starting point for the control, UV and low ozone treatment, whereas it took slightly more than 6 days for the high ozone treatment. Disinfection increased substrate availability and reduced cell densities. Lack of competition and predation induced the recolonization by opportunistic bacteria (r-strategists), with significant increase in bacterial numbers and a low diversity (based on DGGE band pattern). All cultures stabilized after the initial recolonization phase (except Oz700) where competition due to crowding and nutrient limitation favoured bacteria with high substrate affinity (K-strategists), resulting in higher species richness and diversity (based on DGGE band pattern). The bacterial community was significantly altered qualitatively and quantitatively and may have a higher potential as invaders in the recipient depending on disinfection method and the time of release. These results have implications for the treatment strategy used for ballast water. Copyright © 2010 Elsevier Ltd. All rights reserved.

Open-path FTIR ozone measurements in Korea

NASA Astrophysics Data System (ADS)

Walter, William T.; Perry, Stephen H.; Han, Jin-Seok; Park, Chul-Jin

1999-02-01

In July 1997 the Republic of Korea became the 15th country to exceed 10-million registered motor vehicles. The number of cars has been increasing exponentially in Korea for the past 12 years opening an era of one car per household in this nation with a population of 44 million. The air quality effects of the growth of increasingly congested motor vehicle traffic in Seoul, home to more than one-fourth of the entire population, is of great concern to Korea's National Institute of Environmental Research (NIER). AIL's Open-Path FTIR air quality monitor, RAM 2000TM, has been used to quantify the ozone increase over the course of a warm summer day. The RAM 2000 instrument was setup on the roof of the 6-story NIER headquarters. The retroreflector was sited 180-m away across a major highway where it was tripod-mounted on top of the 6- story Korean National Institute of Health facility. During the Open-Path FTIR data taking, NIER Air Physics Division research team periodically tethered an airborne balloon containing pump and a potassium iodide solution to obtain absolute ozone concentration results which indicated that the ambient ozone level was 50 ppb when the Open-Path FTIR measurements began. Total ozone concentrations exceeded 120 ppb for five hours between 11:30 AM and 4:30 PM. The peak ozone concentration measured was 199 ppb at 12:56 PM. The averaged concentration for five and a half hours of data collection was 145 ppb. Ammonia concentrations were also measured.

The Effect of Elevated Ozone Concentrations with Varying Shading on Dry Matter Loss in a Winter Wheat-Producing Region in China.

PubMed

Xu, Jingxin; Zheng, Youfei; He, Yuhong; Wu, Rongjun; Mai, Boru; Kang, Hanqing

2016-01-01

Surface-level ozone pollution causes crop production loss by directly reducing healthy green leaf area available for carbon fixation. Ozone and its precursors also affect crop photosynthesis indirectly by decreasing solar irradiance. Pollutants are reported to have become even more severe in Eastern China over the last ten years. In this study, we investigated the effect of a combination of elevated ozone concentrations and reduced solar irradiance on a popular winter wheat Yangmai13 (Triticum aestivum L.) at field and regional levels in China. Winter wheat was grown in artificial shading and open-top-chamber environments. Treatment 1 (T1, i.e., 60% shading with an enhanced ozone of 100±9 ppb), Treatment 2 (T2, i.e., 20% shading with an enhanced ozone of 100±9 ppb), and Control Check Treatment (CK, i.e., no shading with an enhanced ozone of 100±9 ppb), with two plots under each, were established to investigate the response of winter wheat under elevated ozone concentrations and varying solar irradiance. At the field level, linear temporal relationships between dry matter loss and cumulative stomatal ozone uptake were first established through a parameterized stomatal-flux model. At the regional level, ozone concentrations and meteorological variables, including solar irradiance, were simulated using the WRF-CMAQ model (i.e., a meteorology and air quality modeling system). These variables were then used to estimate cumulative stomatal ozone uptake for the four major winter wheat-growing provinces. The regional-level cumulative ozone uptake was then used as the independent variable in field data-based regression models to predict dry matter loss over space and time. Field-level results showed that over 85% (T1: R(2) = 0.85 & T2: R(2) = 0.89) of variation in dry matter loss was explained by cumulative ozone uptake. Dry matter was reduced by 3.8% in T1 and 2.2% in T2 for each mmol O3·m(-2) of cumulative ozone uptake. At the regional level, dry matter loss in winter wheat would reach 50% under elevated ozone concentrations and reduced solar irradiance as determined in T1, and 30% under conditions as determined in T2. Results from this study suggest that a combination of elevated ozone concentrations and reduced solar irradiance could result in substantial dry matter loss in the Chinese wheat-growing regions.

The Effect of Elevated Ozone Concentrations with Varying Shading on Dry Matter Loss in a Winter Wheat-Producing Region in China

PubMed Central

Xu, Jingxin; Zheng, Youfei; He, Yuhong; Wu, Rongjun; Mai, Boru; Kang, Hanqing

2016-01-01

Surface-level ozone pollution causes crop production loss by directly reducing healthy green leaf area available for carbon fixation. Ozone and its precursors also affect crop photosynthesis indirectly by decreasing solar irradiance. Pollutants are reported to have become even more severe in Eastern China over the last ten years. In this study, we investigated the effect of a combination of elevated ozone concentrations and reduced solar irradiance on a popular winter wheat Yangmai13 (Triticum aestivum L.) at field and regional levels in China. Winter wheat was grown in artificial shading and open-top-chamber environments. Treatment 1 (T1, i.e., 60% shading with an enhanced ozone of 100±9 ppb), Treatment 2 (T2, i.e., 20% shading with an enhanced ozone of 100±9 ppb), and Control Check Treatment (CK, i.e., no shading with an enhanced ozone of 100±9 ppb), with two plots under each, were established to investigate the response of winter wheat under elevated ozone concentrations and varying solar irradiance. At the field level, linear temporal relationships between dry matter loss and cumulative stomatal ozone uptake were first established through a parameterized stomatal-flux model. At the regional level, ozone concentrations and meteorological variables, including solar irradiance, were simulated using the WRF-CMAQ model (i.e., a meteorology and air quality modeling system). These variables were then used to estimate cumulative stomatal ozone uptake for the four major winter wheat-growing provinces. The regional-level cumulative ozone uptake was then used as the independent variable in field data-based regression models to predict dry matter loss over space and time. Field-level results showed that over 85% (T1: R2 = 0.85 & T2: R2 = 0.89) of variation in dry matter loss was explained by cumulative ozone uptake. Dry matter was reduced by 3.8% in T1 and 2.2% in T2 for each mmol O3·m-2 of cumulative ozone uptake. At the regional level, dry matter loss in winter wheat would reach 50% under elevated ozone concentrations and reduced solar irradiance as determined in T1, and 30% under conditions as determined in T2. Results from this study suggest that a combination of elevated ozone concentrations and reduced solar irradiance could result in substantial dry matter loss in the Chinese wheat-growing regions. PMID:26760509

Long-term exposure to ambient ozone and mortality: a quantitative systematic review and meta-analysis of evidence from cohort studies.

PubMed

Atkinson, R W; Butland, B K; Dimitroulopoulou, C; Heal, M R; Stedman, J R; Carslaw, N; Jarvis, D; Heaviside, C; Vardoulakis, S; Walton, H; Anderson, H R

2016-02-23

While there is good evidence for associations between short-term exposure to ozone and a range of adverse health outcomes, the evidence from narrative reviews for long-term exposure is suggestive of associations with respiratory mortality only. We conducted a systematic, quantitative evaluation of the evidence from cohort studies, reporting associations between long-term exposure to ozone and mortality. Cohort studies published in peer-reviewed journals indexed in EMBASE and MEDLINE to September 2015 and PubMed to October 2015 and cited in reviews/key publications were identified via search strings using terms relating to study design, pollutant and health outcome. Study details and estimate information were extracted and used to calculate standardised effect estimates expressed as HRs per 10 ppb increment in long-term ozone concentrations. 14 publications from 8 cohorts presented results for ozone and all-cause and cause-specific mortality. We found no evidence of associations between long-term annual O3 concentrations and the risk of death from all causes, cardiovascular or respiratory diseases, or lung cancer. 4 cohorts assessed ozone concentrations measured during the warm season. Summary HRs for cardiovascular and respiratory causes of death derived from 3 cohorts were 1.01 (95% CI 1.00 to 1.02) and 1.03 (95% CI 1.01 to 1.05) per 10 ppb, respectively. Our quantitative review revealed a paucity of independent studies regarding the associations between long-term exposure to ozone and mortality. The potential impact of climate change and increasing anthropogenic emissions of ozone precursors on ozone levels worldwide suggests further studies of the long-term effects of exposure to high ozone levels are warranted. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Meteorological and chemical impacts on ozone formation: A case study in Hangzhou, China

NASA Astrophysics Data System (ADS)

Li, Kangwei; Chen, Linghong; Ying, Fang; White, Stephen J.; Jang, Carey; Wu, Xuecheng; Gao, Xiang; Hong, Shengmao; Shen, Jiandong; Azzi, Merched; Cen, Kefa

2017-11-01

Regional ozone pollution has become one of the most challenging problems in China, especially in the more economically developed and densely populated regions like Hangzhou. In this study, measurements of O3, CO, NOx and non-methane hydrocarbons (NMHCs), together with meteorological data, were obtained for the period July 1, 2013-August 15, 2013 at three sites in Hangzhou. These sites included an urban site (Zhaohui ;ZH;), a suburban site (Xiasha ;XS;) and a rural site (Qiandaohu ;QDH;). During the observation period, both ZH and XS had a higher ozone level than QDH, with exceeding rates of 41.3% and 47.8%, respectively. Elevated O3 levels in QDH were found at night, which could be explained by less prominent NO titration effect in rural area. Detailed statistical analysis of meteorological and chemical impacts on ozone formation was carried out for ZH, and higher ozone concentration was observed when the wind direction was from the east. This is possibly due to emissions of VOCs from XS, a typical chemical industrial park located in 30 km upwind area of ZH. A comprehensive comparison between three ozone episode periods and one non-episode period were made in ZH. It was concluded that elevated concentrations of precursors and temperatures, low relative humidity and wind speed and easterly-dominated wind direction contribute to urban ozone episodes in Hangzhou. VOCs reactivity analysis indicated that reactive alkenes like isoprene and isobutene contributed most to ozone formation. Three methods were applied to evaluate O3-VOCs-NOx sensitivity in ZH: VOCs/NOx ratio method, Smog Production Model (SPM) and Relative Incremental Reactivity (RIR). The results show that summer ozone in urban Hangzhou mostly presents VOCs-limited and transition region alternately. Our study implies that the increasing automobiles and VOCs emissions from upwind area could result in ozone pollution in urban Hangzhou, and synergistic reduction of VOCs and NOx will be more effective.

Development of nanomaterial-enabled advanced oxidation techniques for treatment of organic micropollutants

NASA Astrophysics Data System (ADS)

Oulton, Rebekah Lynn

Increasing demand for limited fresh water resources necessitates that alternative water sources be developed. Nonpotable reuse of treated wastewater represents one such alternative. However, the ubiquitous presence of organic micropollutants such as pharmaceuticals and personal care products (PPCPs) in wastewater effluents limits use of this resource. Numerous investigations have examined PPCP fate during wastewater treatment, focusing on their removal during conventional and advanced treatment processes. Analysis of influent and effluent data from published studies reveals that at best 1-log10 concentration unit of PPCP removal can generally be achieved with conventional treatment. In contrast, plants employing advanced treatment methods, particularly ozonation and/or membranes, remove most PPCPs often to levels below analytical detection limits. However, membrane treatment is cost prohibitive for many facilities, and ozone treatment can be very selective. Ozone-recalcitrant compounds require the use of Advanced Oxidation Processes (AOPs), which utilize highly reactive hydroxyl radicals (*OH) to target resistant pollutants. Due to cost and energy use concerns associated with current AOPs, alternatives such as catalytic ozonation are under investigation. Catalytic ozonation uses substrates such as activated carbon to promote *OH formation during ozonation. Here, we show that multi-walled carbon nanotubes (MWCNTs) represent another viable substrate, promoting *OH formation during ozonation to levels exceeding activated carbon and equivalent to conventional ozone-based AOPs. Via a series of batch reactions, we observ a strong correlation between *OH formation and MWCNT surface oxygen concentrations. Results suggest that deprotonated carboxyl groups on the CNT surface are integral to their reactivity toward ozone and corresponding *OH formation. From a practical standpoint, we show that industrial grade MWCNTs exhibit similar *OH production as their research-grade counterparts. Accelerated aging studies indicate that MWCNTs maintain surface reactivity for an extended period during ozonation treatment. Further, *OH generation is essentially unaffected in complex water matrices containing known radical scavengers, and is effective for degradation of the ozone-recalcitrant herbicide atrazine. A proof-of-concept study verified that results from batch systems can be replicated in a flow-through reactor utilizing MWCNTs immobilized on a ceramic membrane support. Collective, results suggest that CNT-enhanced ozonation may provide a viable treatment alternative for emerging organic micropollutants.

Influence of altitude on ozone levels and variability in the lower troposphere: a ground-based study for western Europe over the period 2001-2004

NASA Astrophysics Data System (ADS)

Chevalier, A.; Gheusi, F.; Delmas, R.; Ordóñez, C.; Sarrat, C.; Zbinden, R.; Thouret, V.; Athier, G.; Cousin, J.-M.

2007-08-01

The PAES (French acronym for synoptic scale atmospheric pollution) network focuses on the chemical composition (ozone, CO, NOx/y and aerosols) of the lower troposphere (0-3000 m). Its high-altitude surface stations located in different mountainous areas in France complete the low-altitude rural MERA stations (the French contribution to the european program EMEP, European Monitoring and Evaluation Program). They are representative of pollution at the scale of the French territory because they are away from any major source of pollution. This study deals with ozone observations between 2001 and 2004 at 11 stations from PAES and MERA, in addition to 16 elevated stations located in mountainous areas of Switzerland, Germany, Austria, Italy and Spain. The set of stations covers a range of altitudes between 115 and 3550 m. The comparison between recent ozone mixing ratios to those of the last decade at Pic du Midi (2877 m), as well as trends calculated over 14-year data series at three high-altitude sites in the Alps (Jungfraujoch, Sonnblick and Zugspitze) reveal that ozone is still increasing but at a slower rate than in the 1980s and 1990s. The 2001-2004 mean levels of ozone from surface stations capture the ozone stratification revealed by climatological profiles from the airborne observation system MOZAIC (Measurement of OZone and water vapour by Airbus In-service airCraft) and from ozone soundings above Payerne (Switzerland). In particular all data evidence a clear transition at about 1000-1200 m a.s.l. between a sharp gradient below (of the order of +30 ppb/km) and a gentler gradient (+3 ppb/km) above. The same altitude (1200 m) is also found to be a threshold regarding how well the ozone levels at the surface stations agree with the free-tropospheric reference (MOZAIC or soundings). Below the departure can be as large as 40%, but suddenly drops within 15% above. For stations above 2000 m, the departure is even less than 8%. Ozone variability also reveals a clear transition between boundary-layer and free-tropospheric regimes around 1000 m a.s.l. Below, diurnal photochemistry accounts for about the third of the variability in summer, but less than 20% above - and at all levels in winter - where ozone variability is mostly due to day-to-day changes (linked to weather conditions or synoptic transport). In summary, the altitude range 1000-1200 m clearly turns out in our study to be an upper limit below which specific surface effects dominate the ozone content. Monthly-mean ozone mixing-ratios show at all levels a minimum in winter and the classical summer broad maximum in spring and summer - which is actually the superposition of the tropospheric spring maximum (April-May) and regional pollution episodes linked to persistent anticyclonic conditions that may occur from June to September. To complement this classical result it is shown that summer maxima are associated with considerably more variability than the spring maximum. This ensemble of findings support the relevance of mountain station networks such as PAES for the long-term observation of free-tropospheric ozone over Europe.

Ozone contamination in aircraft cabins - Results from GASP data and analyses

NASA Technical Reports Server (NTRS)

Holdeman, J. D.; Nastrom, G. D.

1981-01-01

The paper reviews results from the NASA Global Atmospheric Sampling Program (GASP) pertaining to the problem of ozone contamination in commercial aircraft cabins. Specifically, analyses of GASP data have (1) confirmed the high ozone levels in aircraft cabins and documented the ratio of ozone inside and outside the cabins of two B747 airliners, including the effects of air conditioning modifications on that ratio; (2) defined ambient ozone climatology at commercial aircraft cruise altitudes, including tabulation of encounter frequency data; and (3) outlined procedures for estimating the frequency of flights encountering high cabin ozone levels using climatological ambient ozone data and verified these procedures against cabin measurements.

Ozone contamination in aircraft cabins: Results from GASP data and analyses

NASA Technical Reports Server (NTRS)

Holdeman, J. D.; Nastrom, G. D.

1981-01-01

The global atmospheric sampling program pertaining to the problem of ozone contamination in commercial airplane cabins is described. Specifically, analyses of GASP data have: confirmed the occurrence of high ozone levels in aircraft cabins and documented the ratio of ozone inside and outside the cabins of two B747 airliners, including the effects of air conditioning modifications on that ratio; defined ambient ozone climatology at commercial airplane cruise altitudes, including tabulation of encounter frequency data which were not available before GASP; and outlined procedures for estimating the frequency of flights encountering high cabin ozone levels using climatological ambient ozone data, and verified these procedures against cabin measurements.

What Would Have Happened to the Ozone Layer if Chlorofluorocarbons (CFCs) had not been Regulated?

NASA Technical Reports Server (NTRS)

Newman, Paul A.; Oman, L. D.; Douglass, A. R.; Fleming, E. L.; Frith, S. M.; Hurwitz, M. M.; Kawa, S. R.; Jackman, C. H.; Krotkov, N. A.; Nash, E. R.;

The effect of pre-oxidation on NDMA formation and the influence of pH.

PubMed

Selbes, Meric; Kim, Daekyun; Karanfil, Tanju

2014-12-01

N-nitrosodimethylamine (NDMA), a probable human carcinogen, is a disinfection by-product that has been detected in chloraminated drinking water systems. Pre-oxidation of the NDMA precursors prior to chloramination can be a viable approach for water utilities to control the NDMA levels. This study examined the effects of (i) commonly used oxidants (i.e., chlorine, chlorine dioxide and ozone) in water treatment, (ii) oxidant concentration and contact time (CT), and (iii) pre-oxidation pH on the formation of NDMA from subsequent chloramination. Fifteen model precursors with NDMA molar yields ranging from approximately 0.1%-90% were examined. Pre-chlorination reduced NDMA formation from most precursors by 10%-50% except quaternary amine polymers (i.e., PolyDADMAC, PolyACRYL, PolyAMINE). Pre-oxidation with chlorine dioxide and ozone achieved the same or higher deactivation of NDMA precursors (e.g., ranitidine) while increasing NDMA formation for some other precursors (e.g., daminozid). The increases with chlorine dioxide exposure were attributed to the release of oxidation products with dimethylamine (DMA) moiety, which may form more NDMA upon chloramination than the unoxidizied parent compound. On the other hand, chlorine dioxide was effective, if a precursors NDMA yield were higher than DMA. The ozone-triggered increases could be related to direct NDMA formation from DMA which are released by ozonation of amines with DMA moiety, amides or hydrazines. However, hydroxyl radicals formed from the decomposition of ozone would be also involved in decomposition of formed NDMA, reducing the overall NDMA levels at longer contact times. pH conditions influenced significantly the effectiveness of deactivation of precursors depending on the type of precursor and oxidant used. Copyright © 2014 Elsevier Ltd. All rights reserved.

Assessing the associations of daily respiratory symptoms and lung function in schoolchildren using an Air Quality Index for ozone: Results from the RESPOZE panel study in Athens, Greece.

PubMed

Stergiopoulou, Aravella; Katavoutas, George; Samoli, Evangelia; Dimakopoulou, Konstantina; Papageorgiou, Ifigeneia; Karagianni, Pinelopi; Flocas, Helena; Katsouyanni, Klea

2018-08-15

Air Quality indicators or indices (AQIs) are mainly used for communicating the air pollution levels and risk to the general population. However, very few epidemiological studies have used AQIs for characterizing exposure. In the framework of the RESPOZE panel study we evaluated the association of daily ozone AQI levels with the daily occurrence of respiratory symptoms and Peak Expiratory Flow (PEF) and compared the effects with those estimated using measurements from fixed outdoor monitoring sites, in the city of Athens, Greece. A panel of 97 children, aged 10-11years, was followed intensively for 35days (5weeks) during the academic year 2013-14. PEF and symptoms were recorded daily by each child. Two ozone AQIs classifying the air quality into 7 categories of increasing severity, were calculated; one characterizing the whole Athens area and one the local area around the child's residence and school. Measurements from fixed sites were also used. Mixed effects models for repeated measurements were applied, adjusting for several confounders. Increasing ozone levels were associated with increased incidence of symptoms, but the strongest and most statistically significant associations were found with the local air quality characterization with the AQI. Specifically, an increase in AQI-local by one category was associated with 34% (95% CI: 9%, 64%) increased odds of stuffy nose. When the AQI categories were "Bad" and "Severe", an increase in the incidence of cough was observed (OR 3.05 (95% CI: 1.29, 7.22) and 6.42 (95% CI: 1.47, 28.03) respectively). We did not observe a statistically significant association between AQI and PEF. Our results show that the use of an AQI based on local conditions may be advantageous over the use of only measurements when investigating the effects of air pollution on health outcomes for improving communication of risk to the public. Copyright © 2018 Elsevier B.V. All rights reserved.

Associations between ozone and morbidity using the Spatial Synoptic Classification system

PubMed Central

2011-01-01

Background Synoptic circulation patterns (large-scale tropospheric motion systems) affect air pollution and, potentially, air-pollution-morbidity associations. We evaluated the effect of synoptic circulation patterns (air masses) on the association between ozone and hospital admissions for asthma and myocardial infarction (MI) among adults in North Carolina. Methods Daily surface meteorology data (including precipitation, wind speed, and dew point) for five selected cities in North Carolina were obtained from the U.S. EPA Air Quality System (AQS), which were in turn based on data from the National Climatic Data Center of the National Oceanic and Atmospheric Administration. We used the Spatial Synoptic Classification system to classify each day of the 9-year period from 1996 through 2004 into one of seven different air mass types: dry polar, dry moderate, dry tropical, moist polar, moist moderate, moist tropical, or transitional. Daily 24-hour maximum 1-hour ambient concentrations of ozone were obtained from the AQS. Asthma and MI hospital admissions data for the 9-year period were obtained from the North Carolina Department of Health and Human Services. Generalized linear models were used to assess the association of the hospitalizations with ozone concentrations and specific air mass types, using pollutant lags of 0 to 5 days. We examined the effect across cities on days with the same air mass type. In all models we adjusted for dew point and day-of-the-week effects related to hospital admissions. Results Ozone was associated with asthma under dry tropical (1- to 5-day lags), transitional (3- and 4-day lags), and extreme moist tropical (0-day lag) air masses. Ozone was associated with MI only under the extreme moist tropical (5-day lag) air masses. Conclusions Elevated ozone levels are associated with dry tropical, dry moderate, and moist tropical air masses, with the highest ozone levels being associated with the dry tropical air mass. Certain synoptic circulation patterns/air masses in conjunction with ambient ozone levels were associated with increased asthma and MI hospitalizations. PMID:21609456

Ozone-Induced Vascular Contractility and Pulmonary Injury Are Differentially Impacted by Diets Enriched With Coconut Oil, Fish Oil, and Olive Oil.

PubMed

Snow, Samantha J; Cheng, Wan-Yun; Henriquez, Andres; Hodge, Myles; Bass, Virgina; Nelson, Gail M; Carswell, Gleta; Richards, Judy E; Schladweiler, Mette C; Ledbetter, Allen D; Chorley, Brian; Gowdy, Kymberly M; Tong, Haiyan; Kodavanti, Urmila P

2018-05-01

Fish, olive, and coconut oil dietary supplementation have several cardioprotective benefits, but it is not established if they protect against air pollution-induced adverse effects. We hypothesized that these dietary supplements would attenuate ozone-induced systemic and pulmonary effects. Male Wistar Kyoto rats were fed either a normal diet, or a diet supplemented with fish, olive, or coconut oil for 8 weeks. Animals were then exposed to air or ozone (0.8 ppm), 4 h/day for 2 days. Ozone exposure increased phenylephrine-induced aortic vasocontraction, which was completely abolished in rats fed the fish oil diet. Despite this cardioprotective effect, the fish oil diet increased baseline levels of bronchoalveolar lavage fluid (BALF) markers of lung injury and inflammation. Ozone-induced pulmonary injury/inflammation were comparable in rats on normal, coconut oil, and olive oil diets with altered expression of markers in animals fed the fish oil diet. Fish oil, regardless of exposure, led to enlarged, foamy macrophages in the BALF that coincided with decreased pulmonary mRNA expression of cholesterol transporters, cholesterol receptors, and nuclear receptors. Serum microRNA profile was assessed and demonstrated marked depletion of a variety of microRNAs in animals fed the fish oil diet, several of which were of splenic origin. No ozone-specific changes were noted. Collectively, these data indicate that although fish oil offered vascular protection from ozone exposure, it increased pulmonary injury/inflammation and impaired lipid transport mechanisms resulting in foamy macrophage accumulation, demonstrating the need to be cognizant of potential off-target pulmonary effects that might offset the overall benefit of this vasoprotective supplement.

Associations among plasma metabolite levels and short-term exposure to PM2.5 and ozone in a cardiac catheterization cohort.

PubMed

Breitner, Susanne; Schneider, Alexandra; Devlin, Robert B; Ward-Caviness, Cavin K; Diaz-Sanchez, David; Neas, Lucas M; Cascio, Wayne E; Peters, Annette; Hauser, Elizabeth R; Shah, Svati H; Kraus, William E

2016-12-01

Exposure to ambient particulate matter (PM) and ozone has been associated with cardiovascular disease (CVD). However, the mechanisms linking PM and ozone exposure to CVD remain poorly understood. This study explored associations between short-term exposures to PM with a diameter <2.5μm (PM 2.5 ) and ozone with plasma metabolite concentrations. We used cross-sectional data from a cardiac catheterization cohort at Duke University, North Carolina (NC), USA, accumulated between 2001 and 2007. Amino acids, acylcarnitines, ketones and total non-esterified fatty acid plasma concentrations were determined in fasting samples. Daily concentrations of PM 2.5 and ozone were obtained from a Bayesian space-time hierarchical model, matched to each patient's residential address. Ten metabolites were selected for the analysis based on quality criteria and cluster analysis. Associations between metabolites and PM 2.5 or ozone were analyzed using linear regression models adjusting for long-term trend and seasonality, calendar effects, meteorological parameters, and participant characteristics. We found delayed associations between PM 2.5 or ozone and changes in metabolite levels of the glycine-ornithine-arginine metabolic axis and incomplete fatty acid oxidation associated with mitochondrial dysfunction. The strongest association was seen for an increase of 8.1μg/m 3 in PM 2.5 with a lag of one day and decreased mean glycine concentrations (-2.5% [95% confidence interval: -3.8%; -1.2%]). Short-term exposures to ambient PM 2.5 and ozone is associated with changes in plasma concentrations of metabolites in a cohort of cardiac catheterization patients. Our findings might help to understand the link between air pollution and cardiovascular disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

Stressed lungs: unveiling the role of circulating stress ...

EPA Pesticide Factsheets

Ozone, a major component of smog generated through the interaction of light and anthropogenic emissions, induces adverse pulmonary, cardiovascular, and systemic health effects upon inhalation. It is generally accepted that ozone-induced lung injury is mediated by its interaction with lung lining components causing local oxidative changes, which then leads to cell damage and recruitment of inflammatory cells. It is postulated that the spillover of reactive intermediates and pro-inflammatory molecules from lung to systemic circulation mediates extra-pulmonary effects. However, recent work from our laboratory supports an alternative hypothesis that circulating stress hormones, such as epinephrine and corticosterone/cortisol, are involved in mediating ozone pulmonary effects. We have shown in rats and humans that ozone increases the levels of circulating stress hormones through activation of the hypothalamus- pituitary-adrenal (HPA) axis before any measurable effects are observed in the lung. The surgical removal of adrenals diminishes circulating stress hormones and at the same time, the pulmonary effects of ozone suggesting a significant contribution of these hormones in ozone-induced lung injury and inflammation. While ozone effects in the lung have been extensively studied, the contribution of central nervous system -mediated hormonal stress response has not been examined. In order to understand the signaling pathways that might be involved in ozone-induced lun

Net ozone photochemical production over the eastern and central North Pacific as inferred from GTE/CITE 1 observations during fall 1983

NASA Technical Reports Server (NTRS)

Chameides, W. L.; Davis, D. D.; Rodgers, M. O.; Bradshaw, J.; Sandholm, S.; Sachse, G.; Hill, G.; Gregory, G.

1987-01-01

The role of photochemistry in the budget of tropospheric ozone is studied. Measurements of O3, NO, CO, H2O vapor, and temperature obtained during the fall of 1983 during the GTE/CITE project over the eastern and central North Pacific Ocean are analyzed. The effect of altitude on the measurements is discussed. The analysis reveals a correlation between ozone and NO levels; both increase in concentration and variability with altitude. It is observed that an additional source of secondary importance associated wih CO-rich air parcels exists. A photochemical model is utilized to calculate the net rate of ozone production by photochemical reactions. A net photochemical source of ozone in the free troposphere and a net sink in the boundary layer are detected. The relation between the ozone source in the free troposphere and NO is examined. It is estimated that photochemistry provides a net ozone source to the free troposphere overlying the eastern and central North Pacific Ocean of about 5 x 10 to the 10th molecules/sq cm sec and a net sink of ozone to the boundary layer overlying this region of about 3 x 10 to the 10th molecules/sq cm sec.

Environmental effects of ozone depletion and its interactions with climate change: progress report, 2007.

PubMed

2008-01-01

This year the Montreal Protocol celebrates its 20th Anniversary. In September 1987, 24 countries signed the Montreal Protocol on Substances that Deplete the Ozone Layer. Today 191 countries have signed and have met strict commitments on phasing out of ozone depleting substances with the result that a 95% reduction of these substances has been achieved. The Montreal Protocol has also contributed to slowing the rate of global climate change, since most of the ozone depleting substances are also effective greenhouse gases. Even though much has been achieved, the future of the stratospheric ozone layer relies on full compliance of the Montreal Protocol by all countries for the remaining substances, including methyl bromide, as well as strict monitoring of potential risks from the production of substitute chemicals. Also the ozone depleting substances existing in banks and equipment need special attention to prevent their release to the stratosphere. Since many of the ozone depleting substances already in the atmosphere are long-lived, recovery cannot be immediate and present projections estimate a return to pre-1980 levels by 2050 to 2075. It has also been predicted that the interactions of the effects of the ozone layer and that of other climate change factors will become increasingly important.

Modeling ozone bioindicator injury with microscale and landscape-scale explanatory variables: A logistic regression approach

Treesearch

John W. Coulston

2011-01-01

Tropospheric ozone occurs at phytotoxic levels in the United States (Lefohn and Pinkerton 1988). Several plant species, including commercially important timber species, are sensitive to elevated ozone levels. Exposure to elevated ozone can cause growth reduction and foliar injury and make trees more susceptible to secondary stressors such as insects and pathogens (...

Effect of ozone on photosynthesis, vegetative growth and productivity of prunus salicina' in the San Joaquin Valley of California. (Year 3). Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, L.E.; DeJong, T.M.; Retzlaff, W.A.

1992-10-01

In 1988, an experimental orchard of Cassleman plum (Prunus salicina) was planted in open-top-fumigation chambers and exposed for 4 growing seasons to three ozone concentrations near Fresno, California. During the third year of the study, mean 12-h ozone levels (1991) were 0.034 ppm in the charcoal filtered chambers, 0.050 ppm in the ambient air chambers, 0.94 ppm in the ambient plus added ozone chambers and 0.058 ppm in the no-chamber field plots. Chronic ozone stress has a detrimental effect on photosynthesis, stomatal conductance, leaf appearance and retention, trunk growth, and yield. Yield was 19.8 kg per tree in the charcoalmore » filtered chambers, 15.9 kg/tree in the ambient air chambers, 6.8 kg/tree in the ambient air plus ozone chambers and 15.8 kg/tree in the no-chamber plots. Premature leaf drop and a 35 percent yield loss occurred in 1990 at mean daily ozone concentrations greater than 0.09 ppm (the California Ambient Air Quality Standard). In 1991 the yield loss increased to 65%, indicating cumulative impact on long term productivity.« less

Advanced treatment of biologically pretreated coal chemical industry wastewater using the catalytic ozonation process combined with a gas-liquid-solid internal circulating fluidized bed reactor.

PubMed

Li, Zhipeng; Liu, Feng; You, Hong; Ding, Yi; Yao, Jie; Jin, Chao

2018-04-01

This paper investigated the performance of the combined system of catalytic ozonation and the gas-liquid-solid internal circulating fluidized bed reactor for the advanced treatment of biologically pretreated coal chemical industry wastewater (CCIW). The results indicated that with ozonation alone for 60min, the removal efficiency of chemical oxygen demand (COD) could reach 34%. The introduction of activated carbon, pumice, γ-Al 2 O 3 carriers improved the removal performance of COD, and the removal efficiency was increased by 8.6%, 4.2%, 2%, respectively. Supported with Mn, the catalytic performance of activated carbon and γ-Al 2 O 3 were improved significantly with COD removal efficiencies of 46.5% and 41.3%, respectively; however, the promotion effect of pumice supported with Mn was insignificant. Activated carbon supported with Mn had the best catalytic performance. The catalytic ozonation combined system of MnO X /activated carbon could keep ozone concentration at a lower level in the liquid phase, and promote the transfer of ozone from the gas phase to the liquid phase to improve ozonation efficiency.

Endocrine Activities of Pesticides During Ozonation of Waters.

PubMed

Westlund, Paul; Isazadeh, Siavash; Therrien, Alexandre; Yargeau, Viviane

2018-01-01

Two yeast-based bioassays were used to assess the endocrine activity potential of transformation products formed during the ozonation of water containing a variety of pesticides (propiconazole, atrazine, 2,4-dichlorophenoxyacetic acid [2,4-D], tebuconazole, climbazole, myclobutanil, irgarol, terbutryn, dicamba, mecoprop and diuron). Ozone experiments were conducted first in reverse osmosis water to isolate the effects of the pesticides and then in synthetic wastewater and wastewater effluent to investigate whether the results translated to more complex matrices. The findings demonstrate the recalcitrant nature of most pesticides during ozonation, with removals below 50%, except for irgarol, terbutryn and climbazole with removals up to 70%. This study is the first one to investigate the removal of the fungicides myclobutanil and tebuconazole by ozonation and is one of the first studies to investigate the androgenic activity of ozonation transformation products of contaminants of emerging concern. These findings also demonstrated that during ozonation the initial anti-androgenic activity was removed while the estrogenic activity remained undetected and the androgenic activity increased to levels up to 60% of the anti-androgenic activity of the DHT control. These results indicate that bioactivity should be considered in the evaluation of treatment performance and risks assessment associated to wastewater discharges.

Near-ground ozone source attributions and outflow in central eastern China during MTX2006

NASA Astrophysics Data System (ADS)

Li, J.; Wang, Z.; Akimoto, H.; Yamaji, K.; Takigawa, M.; Pochanart, P.; Liu, Y.; Tanimoto, H.; Kanaya, Y.

2008-12-01

A 3-D regional chemical transport model, the Nested Air Quality Prediction Model System (NAQPMS), with an on-line tracer tagging module was used to study the source of the near-ground (<1.5 km above ground level) ozone at Mt. Tai (36.25° N, 117.10° E, 1534 m a.s.l.) in Central Eastern China (CEC) during the Mount Tai eXperiment 2006 (MTX2006). The model reproduced the temporal and spatial variations of near-ground ozone and other pollutants, and it captured highly polluted and clean cases well. The simulated near-ground ozone level over CEC was 60-85 ppbv (parts per billion by volume), which was higher than values in Japan and over the North Pacific (20-50 ppbv). The simulated tagged tracer data indicated that the regional-scale transport of chemically produced ozone over other areas in CEC contributed to the greatest fraction (49%) of the near-ground mean ozone at Mt. Tai in June; in situ photochemistry contributed only 12%. Due to high anthropogenic and biomass burning emissions that occurred in the southern part of the CEC, the contribution to ground ozone levels from this area played the most important role (32.4 ppbv, 37.9% of total ozone) in the monthly mean ozone concentration at Mt. Tai; values reached 59 ppbv (62%) on 6-7 June 2006. The monthly mean horizontal distribution of chemically produced ozone from various ozone production regions indicated that photochemical reactions controlled the spatial distribution of O3 over CEC. The regional-scale transport of pollutants also played an important role in the spatial and temporal distribution of ozone over CEC. Chemically produced ozone from the southern part of the study region can be transported northeastwardly to the northern rim of CEC; the mean contribution was 5-10 ppbv, and it reached 25 ppbv during high ozone events. Studies of the outflow of CEC ozone and its precursors, as well as their influences and contributions to the ozone level over adjacent regions/countries, revealed that the contribution of CEC ozone to mean ozone mixing ratios over the Korean Peninsula and Japan was 5-15 ppbv, of which about half was due to the direct transport of ozone from CEC and half was produced locally by ozone precursors transported from CEC.

The measurement of ultraviolet radiation and sunburn time over southern Ontario

NASA Technical Reports Server (NTRS)

Evans, W. F. J.

1994-01-01

Studies of the depletion of ozone which have been conducted from the TOMS instrument on the NIMBUS 7 satellite indicate that total ozone has declined by 5 percent over the last 12 years at most mid-latitudes in the Northern Hemisphere typical of southern Ontario. The measurement of the actual resultant increases in UVB is now important. A monitoring program of UVB (biologically active solar ultraviolet radiation) has been conducted for the last 24 months at a site near Bolton, Ontario. The sunburn time varies from less than 17 minutes in late July, to over 4 hours in December on clear days. The levels depend on solar insolation and total ozone column. The ultraviolet levels are strongly affected by cloud and sky conditions. The implications of present and future depletion on the sunburn time are discussed.

The Application of TOMS Ozone, Aerosol and UV-B Data to Madagascar Air Quality Determination

NASA Technical Reports Server (NTRS)

Aikin, A.C.; Einaudi, Franco (Technical Monitor)

2000-01-01

Total Ozone Mapping Spectrometer (TOMS) data products for the area of Madagascar are presented. In addition to total ozone, aerosols and UV-B tropospheric ozone results are shown from 1979 to the present. Tropospheric ozone over Africa and Madagascar is enhanced by 10 to 15 DU in October. This maximum coincides with the time of maximum biomass area burning in Africa and Madagascar. Ozone observations were made from 1979 to 1999 using the TOMS tropospheric ozone convective cloud differential method. As a result of easterly trade winds, ozone originating on Madagascar is transported to the west over the Mozambique Channel. In El Nino years higher level westerly winds descend to transport low level ozone easterly. This results in African continental ozone being transported east of Madagascar. Long range transport of African ozone is observed during El Nino periods. The potential of TOMS and other space data for use in public education and research on Madagascar air quality is demonstrated.

Enhanced treatment of secondary municipal wastewater effluent: comparing (biological) filtration and ozonation in view of micropollutant removal, unselective effluent toxicity, and the potential for real-time control.

PubMed

Chys, Michael; Demeestere, Kristof; Ingabire, Ange Sabine; Dries, Jan; Van Langenhove, Herman; Van Hulle, Stijn W H

2017-07-01

Ozonation and three (biological) filtration techniques (trickling filtration (TF), slow sand filtration (SSF) and biological activated carbon (BAC) filtration) have been evaluated in different combinations as tertiary treatment for municipal wastewater effluent. The removal of 18 multi-class pharmaceuticals, as model trace organic contaminants (TrOCs), has been studied. (Biological) activated carbon filtration could reduce the amount of TrOCs significantly (>99%) but is cost-intensive for full-scale applications. Filtration techniques mainly depending on biodegradation mechanisms (TF and SSF) are found to be inefficient for TrOCs removal as a stand alone technique. Ozonation resulted in 90% removal of the total amount of quantified TrOCs, but a post-ozonation step is needed to cope with an increased unselective toxicity. SSF following ozonation showed to be the only technique able to reduce the unselective toxicity to the same level as before ozonation. In view of process control, innovative correlation models developed for the monitoring and control of TrOC removal during ozonation, are verified for their applicability during ozonation in combination with TF, SSF or BAC. Particularly for the poorly ozone reactive TrOCs, statistically significant models were obtained that correlate TrOC removal and reduction in UVA 254 as an online measured surrogate parameter.

Lagrangian Transport Calculations Using UARS Data. Part 2; Ozone

NASA Technical Reports Server (NTRS)

Manney, Gloria L.; Zurek, R. W.; Froidevaux, L.; Waters, J. W.; ONeill, A.; Swinbank, R.

1995-01-01

Trajectory calculations are used to examine ozone transport in the polar winter stratosphere during periods of the Upper Atmosphere Research Satellite (UARS) observations. The value of these calculations for determining mass transport was demonstrated previously using UARS observations of long-lived tracers, In the middle stratosphere, the overall ozone behavior observed by the Microwave Limb Sounder in the polar vortex is reproduced by this purely dynamical model. Calculations show the evolution of ozone in the lower stratosphere during early winter to be dominated by dynamics in December 1992 in the Arctic. Calculations for June 1992 in the Antarctic show evidence of chemical ozone destruction and indicate that approx. 50% of the chemical destruction may be masked by dynamical effects, mainly diabatic descent, which bring higher ozone into the lower-stratospheric vortex. Estimating differences between calculated and observed fields suggests that dynamical changes masked approx. 20% - 35% of chemical ozone loss during late February and early March 1993 in the Arctic. In the Antarctic late winter, in late August and early September 1992, below approx. 520 K, the evolution of vortex-averaged ozone is entirely dominated by chemical effects; above this level, however, chemical ozone depletion can be partially or completely masked by dynamical effects. Our calculations for 1992 showed that chemical loss was nearly completely compensated by increases due to diabatic descent at 655 K.

A preliminary comparison between TOVS and GOME level 2 ozone data

NASA Astrophysics Data System (ADS)

Rathman, William; Monks, Paul S.; Llewellyn-Jones, David; Burrows, John P.

1997-09-01

A preliminary comparison between total column ozone concentration values derived from TIROS Operational Vertical Sounder (TOVS) and Global Ozone Monitoring Experiment (GOME) has been carried out. Two comparisons of ozone datasets have been made: a) TOVS ozone analysis maps vs. GOME level 2 data; b) TOVS data located at Northern Hemisphere Ground Ozone Stations (NHGOS) vs. GOME data. Both analyses consistently showed an offset in the value of the total column ozone between the datasets [for analyses a) 35 Dobson Units (DU); and for analyses b) 10 DU], despite a good correlation between the spatial and temporal features of the datasets. A noticeably poor correlation in the latitudinal bands 10°/20° North and 10°/20° South was observed—the reasons for which are discussed. The smallest region which was statistically representative of the ozone value correlation dataset of TOVS data at NHGOS and GOME level-2 data was determined to be a region that was enclosed by effective radius of 0.75 arc-degrees (83.5km).

Tropospheric ozone in the Nineteenth Century: The Moncalieri series

NASA Astrophysics Data System (ADS)

Anfossi, D.; Sandroni, S.; Viarengo, S.

1991-09-01

A 26-year (1868-1893) data series of daily ozone readings performed at Moncalieri, northern Italy, by the Schönbein test paper technique has been analyzed. The availability of a series of simultaneous readings by the Schönbein and a quantitative technique (Levy, 1877) and the conversion chart for humidity by Linvill et al. (1980) allowed us to develop a procedure to convert the Moncalieri data into parts per billion by volume values. The results seem to indicate that in comparison to one century ago, the ozone level in Europe has increased by more than twice not only at the surface but also in the free troposphere.

Cell Lysis and Detoxification of Cyanotoxins Using a Novel Combination of Microbubble Generation and Plasma Microreactor Technology for Ozonation

PubMed Central

Pandhal, Jagroop; Siswanto, Anggun; Kuvshinov, Dmitriy; Zimmerman, William B.; Lawton, Linda; Edwards, Christine

2018-01-01

There has been a steady rise in the incidences of algal blooms globally, and worryingly, there is increasing evidence that changes in the global climate are leading to a shift toward cyanobacterial blooms. Many cyanobacterial genera are harmful, producing several potent toxins, including microcystins, for which there are over 90 described analogues. There are a wide range of negative effects associated with these toxins including gastroenteritis, cytotoxicity, hepatotoxicity and neurotoxicity. Although a variety of oxidation based treatment methods have been described, ozonation and advanced oxidation are acknowledged as most effective as they readily oxidise microcystins to non-toxic degradation products. However, most ozonation technologies have challenges for scale up including high costs and sub-optimum efficiencies, hence, a low cost and scalable ozonation technology is needed. Here we designed a low temperature plasma dielectric barrier discharge (DBD) reactor with an incorporated fluidic oscillator for microbubble delivery of ozone. Both technologies have the potential to drastically reduce the costs of ozonation at scale. Mass spectrometry analysis revealed very rapid (<2 min) destruction of two pure microcystins (MC-LR and MC-RR), together with removal of by-products even at low flow rate 1 L min−1 where bubble size was 0.56–0.6 mm and the ozone concentration within the liquid was 20 ppm. Toxicity levels were calculated through protein phosphatase inhibition assays and indicated loss of toxicity as well as confirming the by-products were also non-toxic. Finally, treatment of whole Microcystis aeruginosa cells showed that even at these very low ozone levels, cells can be killed and toxins (MC-LR and Desmethyl MC-LR) removed. Little change was observed in the first 20 min of treatment followed by rapid increase in extracellular toxins, indicating cell lysis, with most significant release at the higher 3 L min−1 flow rate compared to 1 L min−1. This lab-scale investigation demonstrates the potential of the novel plasma micro reactor with applications for in situ treatment of harmful algal blooms and cyanotoxins. PMID:29675015

Cell Lysis and Detoxification of Cyanotoxins Using a Novel Combination of Microbubble Generation and Plasma Microreactor Technology for Ozonation.

PubMed

Pandhal, Jagroop; Siswanto, Anggun; Kuvshinov, Dmitriy; Zimmerman, William B; Lawton, Linda; Edwards, Christine

2018-01-01

There has been a steady rise in the incidences of algal blooms globally, and worryingly, there is increasing evidence that changes in the global climate are leading to a shift toward cyanobacterial blooms. Many cyanobacterial genera are harmful, producing several potent toxins, including microcystins, for which there are over 90 described analogues. There are a wide range of negative effects associated with these toxins including gastroenteritis, cytotoxicity, hepatotoxicity and neurotoxicity. Although a variety of oxidation based treatment methods have been described, ozonation and advanced oxidation are acknowledged as most effective as they readily oxidise microcystins to non-toxic degradation products. However, most ozonation technologies have challenges for scale up including high costs and sub-optimum efficiencies, hence, a low cost and scalable ozonation technology is needed. Here we designed a low temperature plasma dielectric barrier discharge (DBD) reactor with an incorporated fluidic oscillator for microbubble delivery of ozone. Both technologies have the potential to drastically reduce the costs of ozonation at scale. Mass spectrometry analysis revealed very rapid (<2 min) destruction of two pure microcystins (MC-LR and MC-RR), together with removal of by-products even at low flow rate 1 L min -1 where bubble size was 0.56-0.6 mm and the ozone concentration within the liquid was 20 ppm. Toxicity levels were calculated through protein phosphatase inhibition assays and indicated loss of toxicity as well as confirming the by-products were also non-toxic. Finally, treatment of whole Microcystis aeruginosa cells showed that even at these very low ozone levels, cells can be killed and toxins (MC-LR and Desmethyl MC-LR) removed. Little change was observed in the first 20 min of treatment followed by rapid increase in extracellular toxins, indicating cell lysis, with most significant release at the higher 3 L min -1 flow rate compared to 1 L min -1 . This lab-scale investigation demonstrates the potential of the novel plasma micro reactor with applications for in situ treatment of harmful algal blooms and cyanotoxins.

Meteorologically-adjusted trend analysis of surface observed ozone at three monitoring sites in Delhi, India: 2007-2011

NASA Astrophysics Data System (ADS)

Biswas, J.; Farooqui, Z.; Guttikunda, S. K.

2012-12-01

It is well known that meteorological parameters have significant impact on surface ozone concentrations. Therefore it is important to remove the effects of meteorology on ozone concentrations to correctly estimate long-term trends in ozone levels due to the alterations in precursor emissions. This is important for the development of effectual control strategies. In this study surface observed ozone trends in New Delhi are analyzed using Komogorov-Zurbenko (KZ) filter, US EPA ozone adjustment due to weather approach and the classification and regression tree method. The statistical models are applied to the ozone data at three observational sites in New Delhi metropolitan areas, 1) Income Tax Office (ITO) 2) Sirifort and 3) Delhi College of Engineering (DCE). The ITO site is located adjacent to a traffic crossing, Sirifort is an urban site and the DCE site is located in a residential area. The ITO site is also influenced by local industrial emissions. DCE has higher ozone levels than the other two sites. It was found that ITO has lowest ozone concentrations amongst the three sites due to ozone titrating due to industrial and on-road mobile NOx emissions. The statistical methods employed can assess ozone trends at these sites with a high degree of confidence and the results can be used to gauge the effectiveness of control strategies on surface ozone levels in New Delhi.

Surface ozone in China: present-day distribution and long-term changes

NASA Astrophysics Data System (ADS)

Xu, X.; Lin, W.; Xu, W.

2017-12-01

Reliable knowledge of spatio-temporal variations of surface ozone is highly needed to assess the impacts of ozone on human health, ecosystem and climate. Although regional distributions and trends of surface ozone in European and North American countries have been well characterized, little is known about the variability of surface ozone in many other countries, including China, where emissions of ozone precursors have been changing rapidly in recent decades. Here we present the first comprehensive description of present-day (2013-2017) distribution and long-term changes of surface ozone in mainland China. Recent ozone measurements from China's air quality monitoring network (AQMN) are analyzed to show present-day distributions of a few ozone exposure metrics for urban environment. Long-term measurements of ozone at six background sites, a rural site and an urban are used to study the trends of ozone in background, rural and urban air, respectively. The average levels of ozone at the AQMN sites (mainly urban) are close to those found at many European and North American sites. However, ozone at most of the sites shows very large diurnal and seasonal variations so that ozone nonattainment can occur in many cities, particularly those in the North China Plain (NCP), the south of Northeast China (NEC), the Yangtze River Delta (YRD), the Pearl River Delta (PRD), and the Sichuan Basin-Chongqing region (SCB). In all these regions, particularly in the NCP, the maximum daily 8-h average (MDA8) ozone concentration can significantly exceed the national limit (75 ppb). High annual sum of ozone means over 35 ppb (SOMO35) exist mainly in the NCP, NEC and YRD, with regional averages over 4000 ppb·d. Surface ozone has significantly increased at Waliguan (a baseline site in western China) and Shangdianzi (a background site in the NCP), and decreased in winter and spring at Longfengshan (a background site in Northeast China). No clear trend can be derived from long-term measurements of ozone at other sites. Further attention should be paid to future changes of ozone in populated regions of China. Actions are urgently needed to control ozone pollution in the NCP and YRD.

Future changes in tropospheric ozone under Representative Concentration Pathways (RCPs)

NASA Astrophysics Data System (ADS)

Kawase, Hiroaki; Nagashima, Tatsuya; Sudo, Kengo; Nozawa, Toru

2011-03-01

We consider future changes in tropospheric ozone based on the Representative Concentration Pathways (RCPs), which are new emission and concentration scenarios for the 5th coupled model intercomparison project. In contrast to the SRES scenarios, all the RCP scenarios assume an emission reduction of NOx by the late 21st Century that has the potential to achieve tropospheric ozone reduction. However, increasing radiative forcing (RF) due to greenhouse gases and changes in CH4 concentration also contribute to differences in the tropospheric ozone distribution among RCP scenarios. In the RCP4.5 and RCP6.0, assuming the stabilization of RF, the increase in tropospheric ozone due to enhanced residual circulation is cancelled out by the ozone reduction due to ozone precursor reductions. In contrast, in the RCP8.5, assuming increasing RF even after 2100, further enhanced residual circulation and significant increase in CH4 cause a dramatic increase in tropospheric ozone.

Looking at Ozone From a New Angle: Shuttle Ozone Limb Sounding Experiment-2 (SOLSE-2)

NASA Technical Reports Server (NTRS)

McPeters, Richard; Hilsenrath, Ernest; Janz, Scott; Brown, Tammy (Technical Monitor)

2002-01-01

The ozone layer above Earth is our planet's fragile sunscreen, protecting people, vegetation, and wildlife. NASA has been measuring ozone for more than 20 years by looking down, but SOLSE-2 will show that more information is available by looking at ozone from the side, at Earth's limb or atmospheric boundary. When the ozone layer is compromised, increased ultraviolet (UV) levels from the sun cause health problems ranging from severe sunburns to skin cancer and cataracts. A concerted global effort has been made to reduce or eliminate the production of chemicals that deplete ozone, but the ozone layer is not expected to recover for many decades because these chemicals can remain active in the atmosphere for up to 100 years. We know now that ozone monitoring needs to be focused in the lower stratosphere. The discovery of the ozone hole in 1985 demonstrated that very large changes in ozone were occurring in the lower stratosphere near 20 km, instead of the upper stratosphere as first expected, and where current ozone instruments are focused. Measuring ozone from a tangential perspective that is centered at the limb provides ozone profiles concentrated in the lower stratosphere. The first flight of SOLSE proved that this technique achieves the accuracy and coverage of traditional measurements, and surpasses the altitude resolution and depth of retrieval of conventional techniques. Results from the first flight convinced the science community to design the next generation ozone monitoring satellite based on SOLSE. The Ozone Mapping and Profiling Suite (OMPS) is currently being built for the NPOESS satellite. The primary objective of SOLSE-2 is to confirm the promising results of the first flight over a wider range of viewing conditions and spectral wavelengths. Sometimes a really hard problem can be solved when you look at it from a different angle! While scientists conduct research, protect yourself by observing the UV index and spend less unprotected time outdoors.

Nicotiana tabacum as model for ozone - plant surface reactions

NASA Astrophysics Data System (ADS)

Jud, Werner; Fischer, Lukas; Wohlfahrt, Georg; Tissier, Alain; Canaval, Eva; Hansel, Armin

2015-04-01

Elevated tropospheric ozone concentrations are considered a toxic threat to plants, responsible for global crop losses with associated economic costs of several billion dollars per year. The ensuing injuries have been related to the uptake of ozone through the stomatal pores and oxidative effects damaging the internal leaf tissue. A striking question of current research is the environment and plant specific partitioning of ozone loss between gas phase, stomatal or plant surface sink terms. Here we show results from ozone fumigation experiments using various Nicotiana Tabacum varieties, whose surfaces are covered with different amounts of unsaturated diterpenoids exuded by their glandular trichomes. Exposure to elevated ozone levels (50 to 150 ppbv) for 5 to 15 hours in an exceptionally clean cuvette system did neither result in a reduction of photosynthesis nor caused any visible leaf damage. Both these ozone induced stress effects have been observed previously in ozone fumigation experiments with the ozone sensitive tobacco line Bel-W3. In our case ozone fumigation was accompanied by a continuous release of oxygenated volatile organic compounds, which could be clearly associated to their condensed phase precursors for the first time. Gas phase reactions of ozone were avoided by choosing a high enough gas exchange rate of the plant cuvette system. In the case of the Ambalema variety, that is known to exude only the diterpenoid cis-abienol, ozone fumigation experiments yield the volatiles formaldehyde and methyl vinyl ketone (MVK). The latter could be unequivocally separated from isomeric methacrolein (MACR) by the aid of a Selective Reagent Ion Time-of-Flight Mass Spectrometer (SRI-ToF-MS), which was switched every six minutes from H3O+ to NO+ primary ion mode and vice versa. Consistent with the picture of an ozone protection mechanism caused by reactive diterpenoids at the leaf surface are the results from dark-light experiments. The ozone loss obtained from the difference of ozone measured before and after the plant cuvette was investigated as a function of stomatal opening. Switching from dark to light conditions and thus opening the stomata only a small increase in ozone loss was observed for the Ambalema variety (25%). In the case of the 3H02 variety, a line known to emit almost no diterpenoids, the ozone loss increased by more than 100% when changing from dark to light conditions. It is anticipated that the described effect is of importance also for other plant species emitting low-volatility unsaturated organic compounds (e.g. in form of exudates or resins).

Air Pollution and Mortality in the Medicare Population.

PubMed

Di, Qian; Wang, Yan; Zanobetti, Antonella; Wang, Yun; Koutrakis, Petros; Choirat, Christine; Dominici, Francesca; Schwartz, Joel D

2017-06-29

Studies have shown that long-term exposure to air pollution increases mortality. However, evidence is limited for air-pollution levels below the most recent National Ambient Air Quality Standards. Previous studies involved predominantly urban populations and did not have the statistical power to estimate the health effects in underrepresented groups. We constructed an open cohort of all Medicare beneficiaries (60,925,443 persons) in the continental United States from the years 2000 through 2012, with 460,310,521 person-years of follow-up. Annual averages of fine particulate matter (particles with a mass median aerodynamic diameter of less than 2.5 μm [PM 2.5 ]) and ozone were estimated according to the ZIP Code of residence for each enrollee with the use of previously validated prediction models. We estimated the risk of death associated with exposure to increases of 10 μg per cubic meter for PM 2.5 and 10 parts per billion (ppb) for ozone using a two-pollutant Cox proportional-hazards model that controlled for demographic characteristics, Medicaid eligibility, and area-level covariates. Increases of 10 μg per cubic meter in PM 2.5 and of 10 ppb in ozone were associated with increases in all-cause mortality of 7.3% (95% confidence interval [CI], 7.1 to 7.5) and 1.1% (95% CI, 1.0 to 1.2), respectively. When the analysis was restricted to person-years with exposure to PM 2.5 of less than 12 μg per cubic meter and ozone of less than 50 ppb, the same increases in PM 2.5 and ozone were associated with increases in the risk of death of 13.6% (95% CI, 13.1 to 14.1) and 1.0% (95% CI, 0.9 to 1.1), respectively. For PM 2.5 , the risk of death among men, blacks, and people with Medicaid eligibility was higher than that in the rest of the population. In the entire Medicare population, there was significant evidence of adverse effects related to exposure to PM 2.5 and ozone at concentrations below current national standards. This effect was most pronounced among self-identified racial minorities and people with low income. (Supported by the Health Effects Institute and others.).

Tropospheric ozone over Siberia in spring 2010: long-range transport of biomass burning and anthropogenic emissions, stratospheric intrusion and remote boundary layer influence

NASA Astrophysics Data System (ADS)

Berchet, A.; Paris, J.-D.; Ancellet, G.; Law, K.; Stohl, A.; Nédélec, P.; Arshinov, M. Yu; Belan, B. D.; Ciais, P.

2012-04-01

Atmospheric pollution, including tropospheric ozone, has an adverse effect on humans and their environment. The Siberian air shed covers about 10% of Earth's land surface. Therefore, it can contribute significantly to the global tropospheric ozone budget due, in the region, to vast deposition losses on the boreal forest vegetation in the atmospheric surface layer on the one hand, and in-situ photochemical production from ozone precursors emitted by Siberian terrestrial ecosystems, and the influx of stratospheric ozone to the troposphere on the other hand. We have identified and characterized factors that influenced the tropospheric ozone budget over Siberia during spring 2010 by analyzing in-situ measurements of ozone, carbon dioxide, carbon monoxide, and methane mixing ratios collected by continuous analyzers during an intensive airborne measurement campaign of the YAK-AEROSIB Project, carried out between 15 and 18 April 2010. The observations, spanning over 3000 km and stretching from 800 to 6700 m above ground level, were analyzed using the Lagrangian model FLEXPART to simulate backward air mass transport. The analysis of trace gas variability and simulated origin of air masses origins showed that biomass burning and anthropogenic activity expectedly increased carbon monoxide and dioxide concentrations. Also, such plumes coming from east and west of West Siberian plain and from North-Eastern China were shown to increase ozone mixing ratio owing to photochemical processes taking place along the transport route. In the case of low ozone mixing ratios observed over a large area (800x200km) in the upper troposphere above 5500 m the air masses transported to the region under study were likely influenced by an Arctic ozone depletion event transported to lower latitudes and advected to the upper troposphere. The stratospheric source of ozone to the troposphere was observed directly in a well-defined stratospheric intrusion. Numerical simulations of this event suggest an input of 2.56 x 107 kg of ozone associated to a regional downward flux of 9.75 x 1010 molecules·cm-2·s-1.

Drivers of the tropospheric ozone budget throughout the 21st century under the medium-high climate scenario RCP 6.0

NASA Astrophysics Data System (ADS)

Revell, L. E.; Tummon, F.; Stenke, A.; Sukhodolov, T.; Coulon, A.; Rozanov, E.; Garny, H.; Grewe, V.; Peter, T.

2015-01-01

Because tropospheric ozone is both a~greenhouse gas and harmful air pollutant, it is important to understand how anthropogenic activities may influence its abundance and distribution through the 21st century. Here, we present model simulations performed with the chemistry-climate model SOCOL, in which spatially disaggregated chemistry and transport tracers have been implemented in order to better understand the distribution and projected changes in tropospheric ozone. We examine the influences of ozone precursor emissions (nitrogen oxides (NOx), carbon monoxide (CO) and volatile organic compounds (VOCs)), climate change and stratospheric ozone recovery on the tropospheric ozone budget, in a~simulation following the climate scenario Representative Concentration Pathway (RCP) 6.0. Changes in ozone precursor emissions have the largest effect, leading to a global-mean increase in tropospheric ozone which maximises in the early 21st century at 23%. The increase is most pronounced at northern midlatitudes, due to regional emission patterns: between 1990 and 2060, northern midlatitude tropospheric ozone remains at constantly large abundances: 31% larger than in 1960. Over this 70 year period, attempts to reduce emissions in Europe and North America do not have an effect on zonally-averaged northern midlatitude ozone because of increasing emissions from Asia, together with the longevity of ozone in the troposphere. A~simulation with fixed anthropogenic ozone precursor emissions of NOx, CO and non-methane VOCs at 1960 conditions shows a 6 % increase in global-mean tropospheric ozone, and an 11% increase at northern midlatitudes. This increase maximises in the 2080s, and is mostly caused by methane, which maximises in the 2080s following RCP 6.0, and plays an important role in controlling ozone directly, and indirectly through its influence on other VOCs and CO. Enhanced flux of ozone from the stratosphere to the troposphere as well as climate change-induced enhancements in lightning NOx emissions also increase the tropospheric ozone burden, although their impacts are relatively small. Overall, the results show that ozone in the future is governed largely by changes in methane and NOx; methane induces an increase in tropospheric ozone that is approximately one-third of that caused by NOx. Climate impacts on ozone through changes in tropospheric temperature, humidity and lightning NOx remain secondary compared with emission strategies relating to anthropogenic emissions of NOx, such as fossil fuel burning. Therefore, emission policies globally have a critical role to play in determining tropospheric ozone evolution through the 21st century.

Ozone in Sequoia National Park: Linking Ozone Production in the San Joaquin Valley to Trends in Vegetative Impacts in Sequoia National Park from 2000-2016

NASA Astrophysics Data System (ADS)

Buysse, C. E.; Pusede, S.; Kotsakis, A.

2016-12-01

Sequoia National Park (SNP) has the worst ozone air pollution of any National Park in the United States. Ozone pollution levels in SNP are high enough to exert damaging impacts on humans, animals, and vegetation. The major source of ozone to SNP is chemical production within the nearby and ozone-polluted San Joaquin Valley (SJV), which is then transported out of the valley into the park. Emission controls to reduce ozone in the SJV have been in place for the last two decades and these controls should have had the effect of altering ozone levels within SNP. This work has two aims. First, we investigate the chemistry driving trends in ozone in SNP and link these changes to trends in ozone in the SJV. Second, we consider both the metrics and time frames that best capture ozone trends contributing to vegetative damage, as these are not well represented in assessments of human health-based ambient air quality standards over an entire ozone season.

Quantification of Mesophyll Resistance and Apoplastic Ascorbic Acid as an Antioxidant for Tropospheric Ozone in Durum Wheat (Triticum durum Desf. cv. Camacho)

PubMed Central

de la Torre, Daniel

2008-01-01

The daily variations in cellular and apoplastic ascorbic acid and dehydroascorbic acid levels in a Mediterranean durum wheat cultivar (Triticum durum Desf. cv. Camacho) were analyzed in order to relate them to ambient ozone exposure and to subsequent stomatally absorbed ozone fluxes. The aim of this study is to prove the effectiveness and accuracy of a computer model (SODA) to calculate the mesophyll resistance (rm) to ozone uptake, the percentage of ozone detoxification by apoplastic ascorbic acid, and the ozone flux to the plasmalemma (Fm) in a Mediterranean durum wheat cultivar. These calculated factors were related to apoplastic ascorbic acid levels and to ambient ozone concentrations. These relationships were obtained with a view to explaining the detoxification of ozone by apoplastic ascorbic acid. Ozone detoxifications of up to 52% were found at midday, when maximum ozone concentrations and maximum apoplastic ascorbic acid are seen. Mesophyll resistance was minimum at this time, and ozone flux to the plasmalemma was reduced because of the reaction of ozone with apoplastic ascorbic acid. PMID:19082416

Quantification of mesophyll resistance and apoplastic ascorbic acid as an antioxidant for tropospheric ozone in durum wheat (Triticum durum Desf. cv. Camacho).

PubMed

de la Torre, Daniel

2008-12-14

The daily variations in cellular and apoplastic ascorbic acid and dehydroascorbic acid levels in a Mediterranean durum wheat cultivar (Triticum durum Desf. cv. Camacho) were analyzed in order to relate them to ambient ozone exposure and to subsequent stomatally absorbed ozone fluxes. The aim of this study is to prove the effectiveness and accuracy of a computer model (SODA) to calculate the mesophyll resistance (rm) to ozone uptake, the percentage of ozone detoxification by apoplastic ascorbic acid, and the ozone flux to the plasmalemma (Fm) in a Mediterranean durum wheat cultivar. These calculated factors were related to apoplastic ascorbic acid levels and to ambient ozone concentrations. These relationships were obtained with a view to explaining the detoxification of ozone by apoplastic ascorbic acid. Ozone detoxifications of up to 52% were found at midday, when maximum ozone concentrations and maximum apoplastic ascorbic acid are seen. Mesophyll resistance was minimum at this time, and ozone flux to the plasmalemma was reduced because of the reaction of ozone with apoplastic ascorbic acid.

The influence of temperature on ozone production under varying NOx conditions - a modelling study

NASA Astrophysics Data System (ADS)

Coates, Jane; Mar, Kathleen A.; Ojha, Narendra; Butler, Tim M.

2016-09-01

Surface ozone is a secondary air pollutant produced during the atmospheric photochemical degradation of emitted volatile organic compounds (VOCs) in the presence of sunlight and nitrogen oxides (NOx). Temperature directly influences ozone production through speeding up the rates of chemical reactions and increasing the emissions of VOCs, such as isoprene, from vegetation. In this study, we used an idealised box model with different chemical mechanisms (Master Chemical Mechanism, MCMv3.2; Common Representative Intermediates, CRIv2; Model for OZone and Related Chemical Tracers, MOZART-4; Regional Acid Deposition Model, RADM2; Carbon Bond Mechanism, CB05) to examine the non-linear relationship between ozone, NOx and temperature, and we compared this to previous observational studies. Under high-NOx conditions, an increase in ozone from 20 to 40 °C of up to 20 ppbv was due to faster reaction rates, while increased isoprene emissions added up to a further 11 ppbv of ozone. The largest inter-mechanism differences were obtained at high temperatures and high-NOx emissions. CB05 and RADM2 simulated more NOx-sensitive chemistry than MCMv3.2, CRIv2 and MOZART-4, which could lead to different mitigation strategies being proposed depending on the chemical mechanism. The increased oxidation rate of emitted VOC with temperature controlled the rate of Ox production; the net influence of peroxy nitrates increased net Ox production per molecule of emitted VOC oxidised. The rate of increase in ozone mixing ratios with temperature from our box model simulations was about half the rate of increase in ozone with temperature observed over central Europe or simulated by a regional chemistry transport model. Modifying the box model set-up to approximate stagnant meteorological conditions increased the rate of increase of ozone with temperature as the accumulation of oxidants enhanced ozone production through the increased production of peroxy radicals from the secondary degradation of emitted VOCs. The box model simulations approximating stagnant conditions and the maximal ozone production chemical regime reproduced the 2 ppbv increase in ozone per degree Celsius from the observational and regional model data over central Europe. The simulated ozone-temperature relationship was more sensitive to mixing than the choice of chemical mechanism. Our analysis suggests that reductions in NOx emissions would be required to offset the additional ozone production due to an increase in temperature in the future.

Phenols removal using ozonation-adsorption with granular activated carbon (GAC) in rotating packed bed reactor

NASA Astrophysics Data System (ADS)

Karamah, E. F.; Leonita, S.; Bismo, S.

2018-01-01

Synthetic wastewater containing phenols was treated using combination method of ozonation-adsorption with GAC (Granular Activated Carbon) in a packed bed rotating reactor. Ozone reacts quickly with phenol and activated carbon increases the oxidation process by producing hydroxyl radicals. Performance parameters evaluated are phenol removal percentage, the quantity of hydroxyl radical formed, changes in pH and ozone utilization, dissolved ozone concentration and ozone concentration in off gas. The performance of the combination method was compared with single ozonation and single adsorption. The influence of GAC dose and initial pH of phenols were evaluated in ozonation-adsorption method. The results show that ozonation-adsorption method generates more OH radicals than a single ozonation. Quantity of OH radical formation increases with increasing pH and quantity of the GAC. The combination method prove better performance in removing phenols. At the same operation condition, ozonation-adsorption method is capable of removing of 78.62% phenols as compared with single ozonation (53.15%) and single adsorption (36.67%). The increasing percentage of phenol removal in ozonation-adsorption method is proportional to the addition of GAC dose, solution pH, and packed bed rotator speed. Maximum percentage of phenol removal is obtained under alkaline conditions (pH 10) and 125 g of GAC

IL-33 Drives Augmented Responses to Ozone in Obese Mice

PubMed Central

Mathews, Joel A.; Krishnamoorthy, Nandini; Kasahara, David Itiro; Cho, Youngji; Wurmbrand, Allison Patricia; Ribeiro, Luiza; Smith, Dirk; Umetsu, Dale; Levy, Bruce D.; Shore, Stephanie Ann

2016-01-01

Background: Ozone increases IL-33 in the lungs, and obesity augments the pulmonary effects of acute ozone exposure. Objectives: We assessed the role of IL-33 in the augmented effects of ozone observed in obese mice. Methods: Lean wildtype and obese db/db mice were pretreated with antibodies blocking the IL-33 receptor, ST2, and then exposed to ozone (2 ppm for 3 hr). Airway responsiveness was assessed, bronchoalveolar lavage (BAL) was performed, and lung cells harvested for flow cytometry 24 hr later. Effects of ozone were also assessed in obese and lean mice deficient in γδ T cells and their wildtype controls. Results and Discussion: Ozone caused greater increases in BAL IL-33, neutrophils, and airway responsiveness in obese than lean mice. Anti-ST2 reduced ozone-induced airway hyperresponsiveness and inflammation in obese mice but had no effect in lean mice. Obesity also augmented ozone-induced increases in BAL CXCL1 and IL-6, and in BAL type 2 cytokines, whereas anti-ST2 treatment reduced these cytokines. In obese mice, ozone increased lung IL-13+ innate lymphoid cells type 2 (ILC2) and IL-13+ γδ T cells. Ozone increased ST2+ γδ T cells, indicating that these cells can be targets of IL-33, and γδ T cell deficiency reduced obesity-related increases in the response to ozone, including increases in type 2 cytokines. Conclusions: Our data indicate that IL-33 contributes to augmented responses to ozone in obese mice. Obesity and ozone also interacted to promote type 2 cytokine production in γδ T cells and ILC2 in the lungs, which may contribute to the observed effects of IL-33. Citation: Mathews JA, Krishnamoorthy N, Kasahara DI, Cho Y, Wurmbrand AP, Ribeiro L, Smith D, Umetsu D, Levy BD, Shore SA. 2017. IL-33 drives augmented responses to ozone in obese mice. Environ Health Perspect 125:246–253; http://dx.doi.org/10.1289/EHP272 PMID:27472835

Predicting the effects of tropospheric ozone on forest productivity in the Northeastern U.S.

Treesearch

Scott V. Ollinger; John D. Aber; Peter B. Reich

1996-01-01

It is widely believed that tropospheric ozone presents a significant anthropogenic stress on forest ecosystems. Although much information has been collected regarding ozone effects at the seedling and leaf level, we do not have a reliable means of estimating the effect on mature, native forests. For the present study, we incorporated leaf-level ozone response...

Earth's Endangered Ozone

ERIC Educational Resources Information Center

Panofsky, Hans A.

1978-01-01

Included are (1) a discussion of ozone chemistry; (2) the effects of nitrogen fertilizers, fluorocarbons, and high level aircraft on the ozone layer; and (3) the possible results of a decreasing ozone layer. (MR)

Analysis of a rapid increase of stratospheric ozone during late austral summer 2008 over Kerguelen (49.4° S, 70.3° E)

NASA Astrophysics Data System (ADS)

Bencherif, H.; El Amraoui, L.; Kirgis, G.; Leclair de Bellevue, J.; Hauchecorne, A.; Mzé, N.; Portafaix, T.; Pazmino, A.; Goutail, F.

2011-01-01

This paper reports on an increase of ozone event observed over Kerguelen (49.4° S, 70.3° E) in relationship with large-scale isentropic transport. This is evidenced by ground-based observations (co-localised radiosonde and SAOZ experiments) together with satellite global observations (Aura/MLS) assimilated into MOCAGE, a Méteo-France model. The study is based on the analyses of the first ozonesonde experiment never recorded at the Kerguelen site within the framework of a French campaign called ROCK that took place from April to August 2008. Comparisons and interpretations of the observed event are supported by co-localised SAOZ observations, by global mapping of tracers (O3, N2O and columns of O3) from Aura/MLS and Aura/OMI experiments, and by model simulations of Ertel Potential Vorticity initialised by the ECMWF (European Centre for Medium-Range Weather Forecasts) data reanalyses. Satellite and ground-based observational data revealed a consistent increase of ozone in the local stratosphere by mid-April 2008. Additionally, Ozone (O3) and nitrous oxide (N2O) profiles obtained during January-May 2008 using the Microwave Limb Sounder (MLS) aboard the Aura satellite are assimilated into MOCAGE (MOdèle de Chimie Atmosphérique à Grande Echelle), a global three-dimensional chemistry transport model of Météo-France. The assimilated total O3 values are consistent with SAOZ ground observations (within ±5%), and isentropic distributions of O3 match well with maps of advected potential vorticity (APV) derived from the MIMOSA model, a high-resolution advection transport model, and from the ECMWF reanalysis. The event studied seems to be related to the isentropic transport of air masses that took place simultaneously in the lower- and middle-stratosphere, respectively from the polar region and from the tropics to the mid-latitudes. In fact, the ozone increase observed by mid April 2008 resulted simultaneously: (1) from an equator-ward departure of polar air masses characterised with a high-ozone layer in the lower stratosphere (near the 475 K isentropic level), and (2) from a reverse isentropic transport from the tropics to mid- and high-latitudes in the upper stratosphere (nearby the 700 K level). The increase of ozone observed over Kerguelen from the 16-April ozonesonde profile is thus attributed to a concomitant isentropic transport of ozone in two stratospheric layers: the tropical air moving southward and reaching over Kerguelen in the upper stratosphere, and the polar air passing over the same area but in the lower stratosphere.

Modeling the uncertainty of several VOC and its impact on simulated VOC and ozone in Houston, Texas

NASA Astrophysics Data System (ADS)

Pan, Shuai; Choi, Yunsoo; Roy, Anirban; Li, Xiangshang; Jeon, Wonbae; Souri, Amir Hossein

2015-11-01

A WRF-SMOKE-CMAQ modeling system was used to study Volatile Organic Compound (VOC) emissions and their impact on surface VOC and ozone concentrations in southeast Texas during September 2013. The model was evaluated against the ground-level Automated Gas Chromatograph (Auto-GC) measurement data from the Texas Commission on Environmental Quality (TCEQ). The comparisons indicated that the model over-predicted benzene, ethylene, toluene and xylene, while under-predicting isoprene and ethane. The mean biases between simulated and observed values of each VOC species showed clear daytime, nighttime, weekday and weekend variations. Adjusting the VOC emissions using simulated/observed ratios improved model performance of each VOC species, especially mitigating the mean bias substantially. Simulated monthly mean ozone showed a minor change: a 0.4 ppb or 1.2% increase; while a change of more than 5 ppb was seen in hourly ozone data on high ozone days, this change moved model predictions closer to observations. The CMAQ model run with the adjusted emissions better reproduced the variability in the National Aeronautics and Space Administration (NASA)'s Ozone Monitoring Instrument (OMI) formaldehyde (HCHO) columns. The adjusted model scenario also slightly better reproduced the aircraft HCHO concentrations from NASA's DISCOVER-AQ campaign conducted during the simulation episode period; Correlation, Mean Bias and RMSE improved from 0.34, 1.38 ppb and 2.15 ppb to 0.38, 1.33 ppb and 2.08 ppb respectively. A process analysis conducted for both industrial/urban and rural areas suggested that chemistry was the main process contributing to ozone production in both areas, while the impact of chemistry was smaller in rural areas than in industrial and urban areas. For both areas, the positive chemistry contribution increased in the sensitivity simulation largely due to the increase in emissions. Nudging VOC emissions to match the observed concentrations shifted the ozone hotspots outside the industrial/urban region and enhanced the peaked ozone in the outflow region with consistent southerly/southeasterly winds during the afternoon time (1-5 pm). This study helps in the understanding of these processes which are critical to constrain high peak ozone values in the outflow regions. The results indicate that formation of ozone in the outflow could complicate attainment status in neighboring counties.

Modelling and analysis of ozone concentration by artificial intelligent techniques for estimating air quality

NASA Astrophysics Data System (ADS)

Taylan, Osman

2017-02-01

High ozone concentration is an important cause of air pollution mainly due to its role in the greenhouse gas emission. Ozone is produced by photochemical processes which contain nitrogen oxides and volatile organic compounds in the lower atmospheric level. Therefore, monitoring and controlling the quality of air in the urban environment is very important due to the public health care. However, air quality prediction is a highly complex and non-linear process; usually several attributes have to be considered. Artificial intelligent (AI) techniques can be employed to monitor and evaluate the ozone concentration level. The aim of this study is to develop an Adaptive Neuro-Fuzzy inference approach (ANFIS) to determine the influence of peripheral factors on air quality and pollution which is an arising problem due to ozone level in Jeddah city. The concentration of ozone level was considered as a factor to predict the Air Quality (AQ) under the atmospheric conditions. Using Air Quality Standards of Saudi Arabia, ozone concentration level was modelled by employing certain factors such as; nitrogen oxide (NOx), atmospheric pressure, temperature, and relative humidity. Hence, an ANFIS model was developed to observe the ozone concentration level and the model performance was assessed by testing data obtained from the monitoring stations established by the General Authority of Meteorology and Environment Protection of Kingdom of Saudi Arabia. The outcomes of ANFIS model were re-assessed by fuzzy quality charts using quality specification and control limits based on US-EPA air quality standards. The results of present study show that the ANFIS model is a comprehensive approach for the estimation and assessment of ozone level and is a reliable approach to produce more genuine outcomes.

Ozone and Other Air Quality Related Variables Affecting Visibility in the Southeast United States

DTIC Science & Technology

1997-07-11

potential for convective mixing of precursor pollutants. Subsidence impedes the formation of clouds which in turn increases the solar radiation... fact that visibility is not directly related to atmospheric loading by pollutants and aerosols, to nonuniform or nonideal range conditions , and to...ozone levels are most likely to occur during the summer during periods of peak incoming solar radiation. O’Conner (1996) concluded that the best time to

THE IMPACT OF OZONE ON THE LOWER FLAMMABLE LIMIT OF HYDROGEN IN VESSELS CONTAINING SAVANNAH RIVER SITE HIGH LEVEL WASTE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sherburne, Carol; Osterberg, Paul; Johnson, Tom

The Savannah River Site, in conjunction with AREVA Federal services, has designed a process to treat dissolved radioactive waste solids with ozone. It is known that in this radioactive waste process, radionuclides radiolytically break down water into gaseous hydrogen and oxygen, which presents a well defined flammability hazard. Flammability limits have been established for both ozone and hydrogen separately; however, there is little information on mixtures of hydrogen and ozone. Therefore, testing was designed to provide critical flammability information necessary to support safety related considerations for the development of ozone treatment and potential scale-up to the commercial level. Since informationmore » was lacking on flammability issues at low levels of hydrogen and ozone, a testing program was developed to focus on filling this portion of the information gap. A 2-L vessel was used to conduct flammability tests at atmospheric pressure and temperature using a fuse wire ignition source at 1 percent ozone intervals spanning from no ozone to the Lower Flammable Limit (LFL) of ozone in the vessel, determined as 8.4%(v/v) ozone. An ozone generator and ozone detector were used to generate and measure the ozone concentration within the vessel in situ, since ozone decomposes rapidly on standing. The lower flammability limit of hydrogen in an ozone-oxygen mixture was found to decrease from the LFL of hydrogen in air, determined as 4.2 % (v/v) in this vessel. From the results of this testing, Savannah River was able to develop safety procedures and operating parameters to effectively minimize the formation of a flammable atmosphere.« less

Process analysis and economics of drinking water production from coastal aquifers containing chromophoric dissolved organic matter and bromide using nanofiltration and ozonation.

PubMed

Sobhani, R; McVicker, R; Spangenberg, C; Rosso, D

2012-01-01

In regions characterized by water scarcity, such as coastal Southern California, groundwater containing chromophoric dissolved organic matter is a viable source of water supply. In the coastal aquifer of Orange County in California, seawater intrusion driven by coastal groundwater pumping increased the concentration of bromide in extracted groundwater from 0.4 mg l⁻¹ in 2000 to over 0.8 mg l⁻¹ in 2004. Bromide, a precursor to bromate formation is regulated by USEPA and the California Department of Health as a potential carcinogen and therefore must be reduced to a level below 10 μg l⁻¹. This paper compares two processes for treatment of highly coloured groundwater: nanofiltration and ozone injection coupled with biologically activated carbon. The requirement for bromate removal decreased the water production in the ozonation process to compensate for increased maintenance requirements, and required the adoption of catalytic carbon with associated increase in capital and operating costs per unit volume. However, due to the absence of oxidant addition in nanofiltration processes, this process is not affected by bromide. We performed a process analysis and a comparative economic analysis of capital and operating costs for both technologies. Our results show that for the case studied in coastal Southern California, nanofiltration has higher throughput and lower specific capital and operating cost, when compared to ozone injection with biologically activate carbon. Ozone injection with biologically activated carbon, compared to nanofiltration, has 14% higher capital cost and 12% higher operating costs per unit water produced while operating at the initial throughput. Due to reduced ozone concentration required to accommodate for bromate reduction, the ozonation process throughput is reduced and the actual cost increase (per unit water produced) is 68% higher for capital cost and 30% higher for operations. Copyright © 2011 Elsevier Ltd. All rights reserved.

Aircraft cabin ozone measurements on B747-100 and B747-SP aircraft: Correlations with atmospheric ozone and ozone encounter statistics

NASA Technical Reports Server (NTRS)

Perkins, P. J.; Holdeman, J. D.; Gauntner, D. J.

1978-01-01

Simultaneous measurements of atmospheric (outside) ozone concentration and ozone levels in the cabin of the B747-100 and B747-SP airliners were made by NASA to evaluate the aircraft cabin ozone contamination problem. Instrumentation on these aircraft measured ozone from an outside probe and at one point in the cabin. Average ozone in the cabin of the B747-100 was 39 percent of the outside. Ozone in the cabin of the B747-SP measured 82 percent of the outside, before corrective measures. Procedures to reduce the ozone in this aircraft included changes in the cabin air circulation system, use of the high-temperature 15th stage compressor bleed, and charcoal filters in the inlet cabin air ducting, which as separate actions reduced the ozone to 58, 19 and 5 percent, respectively. The potential for the NASA instrumented B747 aircraft to encounter high levels of cabin ozone was derived from atmospheric oxone measurements on these aircraft. Encounter frequencies for two B747-100's were comparable even though the route structures were different. The B747-SP encountered high ozone than did the B747-100's.

On the variability of tropospheric ozone in the Tropical Eastern Pacific and its impact on the oxidizing capacity

NASA Astrophysics Data System (ADS)

Saiz-Lopez, A.; Gomez Martin, J.; Hay, T.; Mahajan, A.; Ordoñez, C.; Parrondo Sempere, M.; Gil, M. J.; Agama Reyes, M.; Paredes Mora, J.; Voemel, H.

2012-12-01

Observations of surface ozone, NOx and meteorological variables were made during two ground based field campaigns in the Eastern Pacific marine boundary layer (MBL). The first study was PIQUERO (Primera Investigación de la Química, Evolución y Reparto de Ozono), running from September 2000 to July 2001 in parallel to the Southern Hemisphere ADditional OZonesondes (SHADOZ) in the Galápagos Islands. The second study is the Climate and HAlogen Reactivity tropicaL EXperiment (CHARLEX), running from September 2010 to present. These long-term, high frequency, measurements enable a detailed description of the daily, monthly, seasonal and interannual variability of ozone and help to constrain the MBL and lower free troposphere (FT) ozone budget. In the Equatorial Eastern Pacific "cold season" (August - October), net ozone photochemical destruction of ~ 2 ppb day-1 occurs in the MBL (~30% due to halogens, and the rest to HOx). Ozone recovers by entrainment from aloft at night. The monthly baseline is set by the tropical instability waves (TIW), which also impact the ozone concentration in the lower FT. In the cold phase of the TIWs the MBL is stratified and, apart from higher surface ozone, it may also contain an upper drier layer with higher ozone between ~ 500 m and the main inversion at ~1 km. In the warm phase the buoyant MBL expands upwards (as much as 500 m) and poor ozone air reaches the FT. As the system shifts to the warm season (February- April), the TIWs stop and the sea becomes warmer, increasing evaporation and reducing ozone. The inversion is pushed upwards and finally disappears or becomes very weak. Surface ozone is so low that even at the low background NOx levels observed ozone production balances photochemical destruction, so the daily profile is flat (observed local effects in the populated areas of Galapagos are discussed). In February Galapagos is almost in the doldrums because the Inter-Tropical Convergence Zone (ITCZ) shifts south. In this situation, air convected at the ITZC is advected at different heights in the FT over Galapagos, so the entrainment of air from the FT does not replenish MBL ozone, explaining the low seasonal minimum. An important aspect of the marked ozone seasonal cycle is the impact on OH. levels. The consequences of this for the oxidizing capacity of the lower atmosphere are discussed.

Environmental Pollutant Ozone Causes Damage to Lung Surfactant Protein B (SP-B)

PubMed Central

2015-01-01

Lung surfactant protein B (SP-B) is an essential protein found in the surfactant fluid at the air–water interface of the lung. Exposure to the air pollutant ozone could potentially damage SP-B and lead to respiratory distress. We have studied two peptides, one consisting of the N-terminus of SP-B [SP-B(1–25)] and the other a construct of the N- and C-termini of SP-B [SP-B(1–25,63–78)], called SMB. Exposure to dilute levels of ozone (∼2 ppm) of monolayers of each peptide at the air–water interface leads to a rapid reaction, which is evident from an increase in the surface tension. Fluorescence experiments revealed that this increase in surface tension is accompanied by a loss of fluorescence from the tryptophan residue at the interface. Neutron and X-ray reflectivity experiments show that, in contrast to suggestions in the literature, the peptides are not solubilized upon oxidation but rather remain at the interface with little change in their hydration. Analysis of the product material reveals that no cleavage of the peptides occurs, but a more hydrophobic product is slowly formed together with an increased level of oligomerization. We attributed this to partial unfolding of the peptides. Experiments conducted in the presence of phospholipids reveal that the presence of the lipids does not prevent oxidation of the peptides. Our results strongly suggest that exposure to low levels of ozone gas will damage SP-B, leading to a change in its structure. The implication is that the oxidized protein will be impaired in its ability to interact at the air–water interface with negatively charged phosphoglycerol lipids, thus compromising what is thought to be its main biological function. PMID:26270023

Low level ozone exposure induces airways inflammation and modifies cell surface phenotypes in healthy humans

EPA Science Inventory

Background: The effects of low level ozone exposure (0.08 ppm) on pulmonary function in healthy young adults are well known, however much less is known about the inflammatory and immuno-modulatory effects oflow level ozone in the airways. Techniques such as induced sputum and flo...

Ground Based, Millimeter Wave Measurement of Ozone in the Middle Atmosphere

NASA Technical Reports Server (NTRS)

Parrish, Alan

2000-01-01

There is a need for highly reliable measurements of stratospheric ozone. Policy makers worldwide concerned with public health rely oil a clear consensus from the scientific community as a basis for ozone-related environmental policy that has a significant impact oil national economies. Tile latest Such consensus was presented in WMO, and used in a 1999 meeting of the parties considering amendments to the Montreal Protocol oil Substances that Deplete the Ozone Layer. Tile scientific community, in turn, needs highly precise and accurate measurements of ozone levels, and small time derivatives of these levels, both in continued - development of its understanding of the physical and chemical processes involved and as clear evidence that these processes are occurring as stated. Over most of the world, changes in ozone levels are small. For example, over the heavily populated northern midlatitudes, the linearized rate of ozone decline is between 0.2% per year and 0.7% per year, depending on altitude. These values are small enough to make measurement requirements technically challenging. Data quality may suffer from imperfections in individual instruments. In one instance, early results from a satellite-borne ozone sensor were later found to be invalid because of calibration drift. Even in the absence of drift, tile absolute calibration of a new sensor may differ slightly from that of its predecessor in service. Most ozone remote sensing instruments operate at ultraviolet or infrared wavelengths where scattering from dust and aerosols must be taken into account; results from these systems may be or are affected following a major volcanic eruption, such as tile one at Mt. Pinatubo in 1991. Given these difficulties, a consensus of measurements from several independent systems is required to insure a reliable understanding of stratospheric ozone levels. Because of the above-described need for highly precise and accurate ozone measurements using several independent techniques, there was interest in developing several techniques which were known but not highly developed in the 1980's into systems capable of being used in ail operational manner to make measurements with the level of quality needed to-detect small trends in ozone levels. A ground-based microwave instrument capable of remotely sensing stratospheric ozone had been designed by tile Principal Investigator of the present project. This instrument was built at tile Millitech Corporation in South Deerfield, Massachusetts before tile present work began. (Funding for design and construction of the instrument came from sources other than the present grant.) Tile instrument measured the spectrum of one of the many emission lines produced by purely rotational transitions of ozone, one at a frequency of 110.8 GHz. The altitude distribution of ozone can. in principle, be retrieved from the details of the pressure-broadened spectrum of the ozone transition. However, the level of contamination of the spectral measurement by instrumentally induced artifacts must be very low in order to retrieve a ozone profile of useful quality from it. The Millitech instrument demonstrated spectral purity at ail adequate level, and there were promising ideas for instrumental improvements and for further development of the technique. The initial objectives of the present project, then, were to develop techniques for calibrating the Millitech instrument, to minimize artifacts in tile spectra it produces, to optimally retrieve ozone profiles from tile spectra, to test tile quality of the microwave profiles by comparing them with profiles obtained using several other, independent techniques over both short and periods of time, and to perform research using the ozone data gathered with the instrument.

Changes in biologically active ultraviolet radiation reaching the Earth's surface.

PubMed

McKenzie, Richard L; Björn, Lars Olof; Bais, Alkiviadis; Ilyasad, Mohammad

2003-01-01

Since publication of the 1998 UNEP Assessment, there has been continued rapid expansion of the literature on UV-B radiation. Many measurements have demonstrated the inverse relationship between column ozone amount and UV radiation, and in a few cases long-term increases due to ozone decreases have been identified. The quantity, quality and availability of ground-based UV measurements relevant to assessing the environmental impacts of ozone changes continue to improve. Recent studies have contributed to delineating regional and temporal differences due to aerosols, clouds, and ozone. Improvements in radiative transfer modelling capability now enable more accurate characterization of clouds, snow-cover, and topographical effects. A standardized scale for reporting UV to the public has gained wide acceptance. There has been increased use of satellite data to estimate geographic variability and trends in UV. Progress has been made in assessing the utility of satellite retrievals of UV radiation by comparison with measurements at the Earth's surface. Global climatologies of UV radiation are now available on the Internet. Anthropogenic aerosols play a more important role in attenuating UV irradiances than has been assumed previously, and this will have implications for the accuracy of UV retrievals from satellite data. Progress has been made inferring historical levels of UV radiation using measurements of ozone (from satellites or from ground-based networks) in conjunction with measurements of total solar radiation obtained from extensive meteorological networks. We cannot yet be sure whether global ozone has reached a minimum. Atmospheric chlorine concentrations are beginning to decrease. However, bromine concentrations are still increasing. While these halogen concentrations remain high, the ozone layer remains vulnerable to further depletion from events such as volcanic eruptions that inject material into the stratosphere. Interactions between global warming and ozone depletion could delay ozone recovery by several years, and this topic remains an area of intense research interest. Future changes in greenhouse gases will affect the future evolution of ozone through chemical, radiative, and dynamic processes In this highly coupled system, an evaluation of the relative importance of these processes is difficult: studies are ongoing. A reliable assessment of these effects on total column ozone is limited by uncertainties in lower stratospheric response to these changes. At several sites, changes in UV differ from those expected from ozone changes alone, possibly as a result of long-term changes in aerosols, snow cover, or clouds. This indicates a possible interaction between climate change and UV radiation. Cloud reflectance measured by satellite has shown a long-term increase at some locations, especially in the Antarctic region, but also in Central Europe, which would tend to reduce the UV radiation. Even with the expected decreases in atmospheric chlorine, it will be several years before the beginning of an ozone recovery can be unambiguously identified at individual locations. Because UV-B is more variable than ozone, any identification of its recovery would be further delayed.

The Two Faces of Ozone.

ERIC Educational Resources Information Center

Monastersky, Richard

1989-01-01

Provides answers to questions regarding the ozone problem: (1) nature of ozone in the troposphere and stratosphere; (2) possibility of sending the excess ozone at ground level to the stratosphere; (3) possibility of producing pure ozone and carrying it to the stratosphere; and (4) banning chlorofluorocarbons. (YP)

Process-scale modeling of elevated wintertime ozone in Wyoming.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kotamarthi, V. R.; Holdridge, D. J.; Environmental Science Division

2007-12-31

Measurements of meteorological variables and trace gas concentrations, provided by the Wyoming Department of Environmental Quality for Daniel, Jonah, and Boulder Counties in the state of Wyoming, were analyzed for this project. The data indicate that highest ozone concentrations were observed at temperatures of -10 C to 0 C, at low wind speeds of about 5 mph. The median values for nitrogen oxides (NOx) during these episodes ranged between 10 ppbv and 20 ppbv (parts per billion by volume). Measurements of volatile organic compounds (VOCs) during these periods were insufficient for quantitative analysis. The few available VOCs measurements indicated unusuallymore » high levels of alkanes and aromatics and low levels of alkenes. In addition, the column ozone concentration during one of the high-ozone episodes was low, on the order of 250 DU (Dobson unit) as compared to a normal column ozone concentration of approximately 300-325 DU during spring for this region. Analysis of this observation was outside the scope of this project. The data analysis reported here was used to establish criteria for making a large number of sensitivity calculations through use of a box photochemical model. Two different VOCs lumping schemes, RACM and SAPRC-98, were used for the calculations. Calculations based on this data analysis indicated that the ozone mixing ratios are sensitive to (a) surface albedo, (b) column ozone, (c) NOx mixing ratios, and (d) available terminal olefins. The RACM model showed a large response to an increase in lumped species containing propane that was not reproduced by the SAPRC scheme, which models propane as a nearly independent species. The rest of the VOCs produced similar changes in ozone in both schemes. In general, if one assumes that measured VOCs are fairly representative of the conditions at these locations, sufficient precursors might be available to produce ozone in the range of 60-80 ppbv under the conditions modeled.« less

The Impact of Increasing Carbon Dioxide on Ozone Recovery

NASA Technical Reports Server (NTRS)

Rosenfield, Joan E.; Douglass, Anne R.; Considine, David B.; Einaudi, Franco (Technical Monitor)

2001-01-01

We have used the GSFC coupled two-dimensional (2D) model to study the impact of increasing carbon dioxide from 1980 to 2050 on the recovery of ozone to its pre-1980 amounts. We find that the changes in temperature and circulation arising from increasing CO2 affect ozone recovery in a manner which varies greatly with latitude, altitude, and time of year. Middle and upper stratospheric ozone recovers faster at all latitudes due to a slowing of the ozone catalytic loss cycles. In the lower stratosphere, the recovery of tropical ozone is delayed due to a decrease in production and a speed up in the overturning circulation. The recovery of high northern latitude lower stratospheric ozone is delayed in spring and summer due to an increase in springtime heterogeneous chemical loss, and is speeded up in fall and winter due to increased downwelling. The net effect on the higher northern latitude column ozone is to slow down the recovery from late March to late July, while making it faster at other times. In the high southern latitudes, the impact of CO2 cooling is negligible. Annual mean column ozone is predicted to recover faster at all latitudes, and globally averaged ozone is predicted to recover approximately ten years faster as a result of increasing CO2.

Effects of temperature-dependent NOx emissions on continental ozone production

NASA Astrophysics Data System (ADS)

Romer, Paul S.; Duffey, Kaitlin C.; Wooldridge, Paul J.; Edgerton, Eric; Baumann, Karsten; Feiner, Philip A.; Miller, David O.; Brune, William H.; Koss, Abigail R.; de Gouw, Joost A.; Misztal, Pawel K.; Goldstein, Allen H.; Cohen, Ronald C.

2018-02-01

Surface ozone concentrations are observed to increase with rising temperatures, but the mechanisms responsible for this effect in rural and remote continental regions remain uncertain. Better understanding of the effects of temperature on ozone is crucial to understanding global air quality and how it may be affected by climate change. We combine measurements from a focused ground campaign in summer 2013 with a long-term record from a forested site in the rural southeastern United States, to examine how daily average temperature affects ozone production. We find that changes to local chemistry are key drivers of increased ozone concentrations on hotter days, with integrated daily ozone production increasing by 2.3 ppb °C-1. Nearly half of this increase is attributable to temperature-driven increases in emissions of nitrogen oxides (NOx), most likely by soil microbes. The increase of soil NOx emissions with temperature suggests that ozone will continue to increase with temperature in the future, even as direct anthropogenic NOx emissions decrease dramatically. The links between temperature, soil NOx, and ozone form a positive climate feedback.

Effect of ozone fumigation on crop composition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pippen, E.L.; Potter, A.L.; Randall, V.G.

1975-01-01

This report describes results of a survey undertaken at the Western Regional Research Laboratory in cooperation with the University of California at Riverside. Cabbage, carrots, corn, lettuce, strawberries, and tomatoes harvested from plants grown in (1) clean air (carbon-filtered air); (2) clean air fumigated with a low ozone level; and (3) clean air fumigated with a high ozone level were studied. The two ozone levels used (approximately 200 and 350 ppB O/sub 3/) represented levels commonly observed in the air in Southern California in summer and fall. Items determined quantitatively included five vitamins, solids, nitrogen, fiber, ash carbohydrate, and upmore » to nine metals. The metals Ca, Cu, Fe, Pb, Mn, K, Rb, Sr, and Zn were determined using X-ray fluorescence spectroscopy. With the metals significant differences occurred with different plants. The nonmetal nutrients showed that ozone had some effect on the crops. Carotene, vitamin C, thiamine, and riboflavin were studied. This survey indicated that ozone did not have a major and generally deleterious impact on crop composition. It indicated some areas where ozone influenced crop composition. 14 references, 5 tables.« less

Growth, yield and quality attributes of a tropical potato variety (Solanum tuberosum L. cv Kufri chandramukhi) under ambient and elevated carbon dioxide and ozone and their interactions.

PubMed

Kumari, Sumita; Agrawal, Madhoolika

2014-03-01

The present study was designed to study the growth and yield responses of a tropical potato variety (Solanum tuberosum L. cv. Kufri chandramukhi) to different levels of carbon dioxide (382 and 570ppm) and ozone (50 and 70ppb) in combinations using open top chambers (OTCs). Plants were exposed to three ozone levels in combination with ambient CO2 and two ozone levels at elevated CO2. Significant increments in leaf area and total biomass were observed under elevated CO2 in combination with ambient O3 (ECO2+AO3) and elevated O3 (ECO2+EO3), compared to the plants grown under ambient concentrations (ACO2+AO3). Yield measured as fresh weight of potato also increased significantly under ECO2+AO3 and ECO2+EO3. Yield, however, reduced under ambient (ACO2+AO3) and elevated ozone (ACO2+EO3) compared to ACO2 (filtered chamber). Number, fresh and dry weights of tubers of size 35-50mm and>50mm used for direct consumption and industrial purposes, respectively increased maximally under ECO2+AO3. Ambient as well as elevated levels of O3 negatively affected the growth parameters and yield mainly due to reductions in number and weight of tubers of sizes >35mm. The quality of potato tubers was also modified under different treatments. Starch content increased and K, Zn and Fe concentrations decreased under ECO2+AO3 and ECO2+EO3 compared to ACO2+AO3. Starch content reduced under ACO2+AO3 and ACO2+EO3 treatments compared to ACO2. These results clearly suggest that elevated CO2 has provided complete protection to ambient O3 as the potato yield was higher under ECO2+AO3 compared to ACO2. However, ambient CO2 is not enough to protect the plants under ambient O3 levels. Elevated CO2 also provided protection against elevated O3 by improving the yield. Quality of tubers is modified by both CO2 and O3, which have serious implications on human health at present and in future. Copyright © 2013 Elsevier Inc. All rights reserved.

Ozone and nitrogen effects on yield and nutritive quality of the annual legume Trifolium cherleri

NASA Astrophysics Data System (ADS)

Sanz, J.; González-Fernández, I.; Calvete-Sogo, H.; Lin, J. S.; Alonso, R.; Muntifering, R.; Bermejo, V.

2014-09-01

Two independent experiments were performed in an Open-Top Chamber facility to determine the response of biomass and nutritive quality of the annual legume Trifolium cherleri to increased levels of ozone (O3) and nitrogen (N) deposition, two main drivers of global change. Plants growing in pots were exposed to three O3 treatments: charcoal-filtered air (CFA); non-filtered air, reproducing ambient O3 levels of the site (NFA); and non-filtered air supplemented with 40 nl l-1 (NFA+). Nitrogen was added in biweekly doses to achieve final doses of 5 (N5), 15 (N15) and 30 kg ha-1 (N30), reproducing the N deposition range in the Iberian Peninsula. Ozone negatively affected all the growth-related parameters and increased plant senescent biomass. The pollutant affected subterranean biomass to a greater extent than aerial biomass, resulting in altered aerial/subterranean ratio. Effects in the second experiment followed the same pattern as in the first, but were of lesser magnitude. However, these differences between assays could not be explained adequately by the absorbed O3 fluxes (Phytotoxic Ozone Dose, POD). Concentrations of cell-wall constituents related to nutritive quality increased with the O3 exposure, reducing the Relative Food Value index (RFV) that indicates decreased nutritive quality of the forage. Nitrogen stimulated all growth-related parameters, but increased the aboveground biomass more than the subterranean biomass. No effects of N fertilizer were detected for the nutritive quality parameters. A significant interaction between O3 and N was found in the second experiment. N further enhanced the increase of senescent biomass caused by O3. Results indicate that O3 is a potentially significant environmental stress factor in terms of structure and diversity of Mediterranean pastures.

Detection and Attribution of the Recovery of Polar Ozone

NASA Technical Reports Server (NTRS)

Newman, Paul A.; Nash, E. R.; Douglass, A. R.; Nielsen, J. E.; Pawson, S.; Stolarski, R. S.

2008-01-01

The Antarctic ozone hole develops each year and culminates by early spring (late September - early October). The severity of the hole has been assessed from satellites using the minimum total ozone value from the October monthly mean (depth of the hole), calculating the average area coverage during this September-October period, and by estimating ozone mass deficit. Profile information shows that ozone is completely destroyed in the 14-2 1 km layer by early October. Ozone is mainly destroyed by halogen (chlorine and bromine) catalytic cycles, and these losses are modulated by temperature variations. Because atmospheric halogen levels are responding to international agreements that limit or phase out production, the amount of halogens in the stratosphere should decrease over the next few decades. Both models and projections of ozone depleting substances (ODSs) into the 21St century reveal that polar ozone levels should recover in the 2060- 2070 period. In this talk, we will review current projections of polar ozone recovery. Using models and ODs projections, we explore both the past, near future (2008-2025), and far future (> 2025) levels of polar ozone. Finally, we will discuss various factors that complicate recovery such as greenhouse gas changes (e.g., cooling in the upper stratosphere) and the acceleration of the Brewer-Dobson circulation.

Estimating when the Antarctic Ozone Hole will Recover

NASA Technical Reports Server (NTRS)

Newman, Paul A.; Nash, Eric R.; Douglass, Anne R.; Nielsen, J. Eric; Pawson, Steven; Stolarski, Richard S.

2007-01-01

The Antarctic ozone hole develops each year and culminates by early spring (late September - early October). The severity of the hole has been assessed from satellites using the minimum total ozone value from the October monthly mean (depth of the hole) and by calculating the average area coverage during this September-October period. Profile information shows that ozone is completely destroyed in the 14-2 1 km layer by early October. Ozone is mainly destroyed by halogen (chlorine and bromine) catalytic cycles, and these losses are modulated by temperature variations. Because atmospheric halogen levels are responding to international a'greements that limit or phase out production, the amount of halogens in the stratosphere should decrease over the next few decades. Using projections of halogen levels combined with age-of-air estimates, we find that the ozone hole is recovering at an extremely slow rate and that large ozone holes will regularly recur over the next 2 decades. We estimate that the ozone hole will begin to show first signs of size decrease in about 2023, and the hole will fully recover to pre-1980 levels in approximately 2070. Estimates of the ozone hole's recovery from models reveal important differences that will be discussed.

Estimating When the Antarctic Ozone Hole Will Recover

NASA Technical Reports Server (NTRS)

Newman, Paul A.; Nash, Eric R.; Douglass, Anne R.; Nielsen, J. Eric; Pawson, Steven; Stolarski, Richard S.

2007-01-01

The Antarctic ozone hole develops each year and culminates by early spring (late September - early October). The severity of the hole has been assessed from satellites using the minimum total ozone value from the October monthly mean (depth of the hole) and by calculating the average area coverage during this September-October period. Profile information shows that ozone is completely destroyed in the 14-21 km layer by early October. Ozone is mainly destroyed by halogen (chlorine and bromine) catalytic cycles, and these losses are modulated by temperature variations. Because atmospheric halogen levels are responding to international agreements that limit or phase out production, the amount of halogens in the stratosphere should decrease over the next few decades. Using projections of halogen levels combined with age-of-air estimates, we find that the ozone hole is recovering at an extremely slow rate and that large ozone holes will regularly recur over the next 2 decades. We estimate that the ozone hole will begin to show first signs of size decrease in about 2023, and the hole will fully recover to pre-1980 levels in approximately 2070. Estimates of the ozone hole's recovery from models reveal important differences that will be discussed.

Long-term Measurements of Summer-time Ozone at the Walnut Grove Tower - Understanding Trends in the Boundary Layer

NASA Astrophysics Data System (ADS)

Mahmud, A.; Di, P.; Mims, D.; Avise, J.; DaMassa, J.; Kaduwela, A. P.

2015-12-01

The California Air Resources Board (CARB) has been monitoring boundary layer ozone at the Walnut Grove Tower (WGT) since 1996 for investigating regional transport and vertical profile. Walnut Grove is located between Sacramento and Stockton, CA in the Sacramento - San Joaquin Delta. Sampling inlets are positioned at 30-ft, 400-ft, 800-ft, 1200-ft and 1600-ft levels of the 2000-ft tower, which is one of the tallest monitoring towers in the Western US. Ozone, ambient temperature, wind speed, and wind direction are simultaneously measured at each level, and reported as hourly averages. The current study included analyses of available ozone and corresponding meteorological data for the months of June - September from 1996 - 2014 with objectives to: 1) explore trends and inter-annual variability of ozone, 2) examine any correlations between ozone and meteorological parameters, 3) understand interactions of ozone measured at various levels, and 4) assess how well a regulatory state-of-the-science air quality model such as the Community Multi-scale Air Quality Model (CMAQ) captures observation. Daily 1-hr maximum ozone has been consistently decreasing during the 1996 - 2014 period at a rate of ~1 ppb per year. This indicates that CARB's measures to control ambient ozone have been effective over the past years. Evolution of the vertical profile throughout the day shows that ozone is fairly homogeneously mixed between 1 - 5 pm, when mixing height typically reaches the maximum. Ozone at 30-ft shows the greatest variability because of its proximity to the ground and emissions sources - rises faster during morning hours (7 - 10 am) and declines more rapidly during evening hours (7 - 10 pm) compared to other levels. Air masses reaching the tower are predominantly southwesterly (247 - 257 deg.) at the bottom, and southwesterly to slightly northwesterly (254 - 302 deg.) at top levels. Daily 1-hr maximum ozone was negatively correlated with wind speed (i.e. ozone was high under low wind condition) and positively correlated with ambient temperature (i.e. ozone was high under high temperature condition) during ~40% and ~50% of the time, respectively. A modeling exercise for Jun - Sep of 2012 shows that CMAQ captures the observed evolution and vertical mixing of ozone throughout the day quite well in the boundary layer.

Field-Testing for Ozone: Analyzing Air Quality in Your Hometown.

ERIC Educational Resources Information Center

Lee, Judy; DeRulle, Joyce

1995-01-01

Describes a project designed to teach students how to measure ground-level ozone and determine ozone concentrations. Enables students to research the effects of ozone exposure and discuss ways to clean up the problem. Includes an activity based on the oxidation capability of ozone. (JRH)

A Hybrid Model for Spatially and Temporally Resolved Ozone Exposures in the Continental United States

PubMed Central

Di, Qian; Rowland, Sebastian; Koutrakis, Petros; Schwartz, Joel

2017-01-01

Ground-level ozone is an important atmospheric oxidant, which exhibits considerable spatial and temporal variability in its concentration level. Existing modeling approaches for ground-level ozone include chemical transport models, land-use regression, Kriging, and data fusion of chemical transport models with monitoring data. Each of these methods has both strengths and weaknesses. Combining those complementary approaches could improve model performance. Meanwhile, satellite-based total column ozone, combined with ozone vertical profile, is another potential input. We propose a hybrid model that integrates the above variables to achieve spatially and temporally resolved exposure assessments for ground-level ozone. We used a neural network for its capacity to model interactions and nonlinearity. Convolutional layers, which use convolution kernels to aggregate nearby information, were added to the neural network to account for spatial and temporal autocorrelation. We trained the model with AQS 8-hour daily maximum ozone in the continental United States from 2000 to 2012 and tested it with left out monitoring sites. Cross-validated R2 on the left out monitoring sites ranged from 0.74 to 0.80 (mean 0.76) for predictions on 1 km×1 km grid cells, which indicates good model performance. Model performance remains good even at low ozone concentrations. The prediction results facilitate epidemiological studies to assess the health effect of ozone in the long term and the short term. PMID:27332675

Kinetic assessment and modeling of an ozonation step for full-scale municipal wastewater treatment: micropollutant oxidation, by-product formation and disinfection.

PubMed

Zimmermann, Saskia G; Wittenwiler, Mathias; Hollender, Juliane; Krauss, Martin; Ort, Christoph; Siegrist, Hansruedi; von Gunten, Urs

2011-01-01

The kinetics of oxidation and disinfection processes during ozonation in a full-scale reactor treating secondary wastewater effluent were investigated for seven ozone doses ranging from 0.21 to 1.24 g O(3) g(-1) dissolved organic carbon (DOC). Substances reacting fast with ozone, such as diclofenac or carbamazepine (k(P, O3) > 10(4) M(-1) s(-1)), were eliminated within the gas bubble column, except for the lowest ozone dose of 0.21 g O(3) g(-1) DOC. For this low dose, this could be attributed to short-circuiting within the reactor. Substances with lower ozone reactivity (k(P, O3) < 10(4) M(-1) s(-1)) were only fully eliminated for higher ozone doses. The predictions of micropollutant oxidation based on coupling reactor hydraulics with ozone chemistry and reaction kinetics were up to a factor of 2.5 higher than full-scale measurements. Monte Carlo simulations showed that the observed differences were higher than model uncertainties. The overestimation of micropollutant oxidation was attributed to a protection of micropollutants from ozone attack by the interaction with aquatic colloids. Laboratory-scale batch experiments using wastewater from the same full-scale treatment plant could predict the oxidation of slowly-reacting micropollutants on the full-scale level within a factor of 1.5. The Rct value, the experimentally determined ratio of the concentrations of hydroxyl radicals and ozone, was identified as a major contribution to this difference. An increase in the formation of bromate, a potential human carcinogen, was observed with increasing ozone doses. The final concentration for the highest ozone dose of 1.24 g O(3) g(-1) DOC was 7.5 μg L(-1), which is below the drinking water standard of 10 μg L(-1). N-Nitrosodimethylamine (NDMA) formation of up to 15 ng L(-1) was observed in the first compartment of the reactor, followed by a slight elimination during sand filtration. Assimilable organic carbon (AOC) increased up to 740 μg AOC L(-1), with no clear trend when correlated to the ozone dose, and decreased by up to 50% during post-sand filtration. The disinfection capacity of the ozone reactor was assessed to be 1-4.5 log units in terms of total cell counts (TCC) and 0.5 to 2.5 log units for Escherichia coli (E. coli). Regrowth of up to 2.5 log units during sand filtration was observed for TCC while no regrowth occurred for E. coli. E. coli inactivation could not be accurately predicted by the model approach, most likely due to shielding of E. coli by flocs. Copyright © 2010 Elsevier Ltd. All rights reserved.

Long-term trends of surface ozone and its influencing factors at the Mt Waliguan GAW station, China - Part 1: Overall trends and characteristics

NASA Astrophysics Data System (ADS)

Xu, Wanyun; Lin, Weili; Xu, Xiaobin; Tang, Jie; Huang, Jianqing; Wu, Hao; Zhang, Xiaochun

2016-05-01

Tropospheric ozone is an important atmospheric oxidant, greenhouse gas and atmospheric pollutant at the same time. The oxidation capacity of the atmosphere, climate, human and vegetation health can be impacted by the increase of the ozone level. Therefore, long-term determination of trends of baseline ozone is highly needed information for environmental and climate change assessment. So far, studies on the long-term trends of ozone at representative sites are mainly available for European and North American sites. Similar studies are lacking for China and many other developing countries. Measurements of surface ozone were carried out at a baseline Global Atmospheric Watch (GAW) station in the north-eastern Tibetan Plateau region (Mt Waliguan, 36°17' N, 100°54' E, 3816 m a.s.l.) for the period of 1994 to 2013. To uncover the variation characteristics, long-term trends and influencing factors of surface ozone at this remote site in western China, a two-part study has been carried out, with this part focusing on the overall characteristics of diurnal, seasonal and long-term variations and the trends of surface ozone. To obtain reliable ozone trends, we performed the Mann-Kendall trend test and the Hilbert-Huang transform (HHT) analysis on the ozone data. Our results confirm that the mountain-valley breeze plays an important role in the diurnal cycle of surface ozone at Waliguan, resulting in higher ozone values during the night and lower ones during the day, as was previously reported. Systematic diurnal and seasonal variations were found in mountain-valley breezes at the site, which were used in defining season-dependent daytime and nighttime periods for trend calculations. Significant positive trends in surface ozone were detected for both daytime (0.24 ± 0.16 ppbv year-1) and nighttime (0.28 ± 0.17 ppbv year-1). The largest nighttime increasing rate occurred in autumn (0.29 ± 0.11 ppbv year-1), followed by spring (0.24 ± 0.12 ppbv year-1), summer (0.22 ± 0.20 ppbv year-1) and winter (0.13 ± 0.10 ppbv year-1), respectively. The HHT spectral analysis identified four different stages with different positive trends, with the largest increase occurring around May 2000 and October 2010. The HHT results suggest that there were 2-4a, 7a and 11a periodicities in the time series of surface ozone at Waliguan. The results of this study can be used for assessments of climate and environment change and in the validation of chemistry-climate models.

Vertical profile of tropospheric ozone derived from synergetic retrieval using three different wavelength ranges, UV, IR, and microwave: sensitivity study for satellite observation

NASA Astrophysics Data System (ADS)

Sato, Tomohiro O.; Sato, Takao M.; Sagawa, Hideo; Noguchi, Katsuyuki; Saitoh, Naoko; Irie, Hitoshi; Kita, Kazuyuki; Mahani, Mona E.; Zettsu, Koji; Imasu, Ryoichi; Hayashida, Sachiko; Kasai, Yasuko

2018-03-01

We performed a feasibility study of constraining the vertical profile of the tropospheric ozone by using a synergetic retrieval method on multiple spectra, i.e., ultraviolet (UV), thermal infrared (TIR), and microwave (MW) ranges, measured from space. This work provides, for the first time, a quantitative evaluation of the retrieval sensitivity of the tropospheric ozone by adding the MW measurement to the UV and TIR measurements. Two observation points in East Asia (one in an urban area and one in an ocean area) and two observation times (one during summer and one during winter) were assumed. Geometry of line of sight was nadir down-looking for the UV and TIR measurements, and limb sounding for the MW measurement. The retrieval sensitivities of the ozone profiles in the upper troposphere (UT), middle troposphere (MT), and lowermost troposphere (LMT) were estimated using the degree of freedom for signal (DFS), the pressure of maximum sensitivity, reduction rate of error from the a priori error, and the averaging kernel matrix, derived based on the optimal estimation method. The measurement noise levels were assumed to be the same as those for currently available instruments. The weighting functions for the UV, TIR, and MW ranges were calculated using the SCIATRAN radiative transfer model, the Line-By-Line Radiative Transfer Model (LBLRTM), and the Advanced Model for Atmospheric Terahertz Radiation Analysis and Simulation (AMATERASU), respectively. The DFS value was increased by approximately 96, 23, and 30 % by adding the MW measurements to the combination of UV and TIR measurements in the UT, MT, and LMT regions, respectively. The MW measurement increased the DFS value of the LMT ozone; nevertheless, the MW measurement alone has no sensitivity to the LMT ozone. The pressure of maximum sensitivity value for the LMT ozone was also increased by adding the MW measurement. These findings indicate that better information on LMT ozone can be obtained by adding constraints on the UT and MT ozone from the MW measurement. The results of this study are applicable to the upcoming air-quality monitoring missions, APOLLO, GMAP-Asia, and uvSCOPE.

Exceedance of PM10 and ozone concentration limits in Germany - Spatial variability and influence of climate

NASA Astrophysics Data System (ADS)

Heidenreich, Majana; Bernhofer, Christian

2014-05-01

High concentrations of particulate matter (PM) and ground-level ozone (O3) have negative impacts on human health, e.g., increased risk of respiratory disease, and the environment. European Union (EU) air policy and air quality standards led to continuously reduced air pollution problems in recent decades. Nevertheless, the limit values for PM10 (particles with diameter of 10 micrometers or less) and ozone - defined by the directive 2008/50/EC of the European Parliament - are still exceeded frequently. Poor air quality and the exceedance of limits result mainly from the combination of high emissions and unfavourable weather conditions. Datasets from German monitoring stations are used to describe the spatial and temporal variability of the exceedance of concentration limits for PM10 and ozone for the federal states of Germany. Time series are analysed for the period 2000-2012 for PM10 and for the period 1990-2012 for ozone. Furthermore, the influence of weather patterns on the exceedance of concentration limits on a regional scale was investigated. Here, the "objective weather types" of the German Weather Service were used. As expected, for most regions anticyclonic weather types (with a negative cyclonality index for the two levels 950 and 500 hPa) show a high frequency on exeedance days, both for PM10 and ozone. The results could contribute to estimate the future exceedance frequency of concentration limits and to develop possible countermeasures.

[The two ozone problems: too much in the troposphere, too little in the stratosphere].

PubMed

Staehelin, J

1992-03-10

Trends analysis based on the long-term Swiss ozone measurements from Arosa and Payerne operationally performed by the Swiss Meteorological Institute are presented. These measurement include stratospheric ozone (approximately 90% of total ozone) and tropospheric ozone. The total ozone measurements from Arosa, the world longest series started at 1926, indicate, that total ozone has declined since about 1970 by approximately 5%. The ozone balloon soundings, operationally performed at Payerne since 1969 (2-3 ascents per week) show, that stratospheric ozone has decreased strongly in the last 20 years, whereas tropospheric ozone, remarkably has increased during this period. The relative change was strongest in the troposphere (more than 10% per decade, 3-4% increase per year during 1982-1988). However, on an absolute scale, changes in the stratosphere were strongest (relative decrease: 6 to 7% per decade at 20-22 km). The present scientific theories of the two ozone problems are reviewed: stratospheric ozone decrease was caused by the anthropogenic emissions of fluorochlorocarbons and other compounds mainly released from the earth surface. Tropospheric ozone has increased due to photochemical production of mainly anthropogenically emitted nitrogen oxides, volatile organic compounds and CO.

Drivers of the tropospheric ozone budget throughout the 21st century under the medium-high climate scenario RCP 6.0

NASA Astrophysics Data System (ADS)

Revell, L. E.; Tummon, F.; Stenke, A.; Sukhodolov, T.; Coulon, A.; Rozanov, E.; Garny, H.; Grewe, V.; Peter, T.

2015-05-01

Because tropospheric ozone is both a greenhouse gas and harmful air pollutant, it is important to understand how anthropogenic activities may influence its abundance and distribution through the 21st century. Here, we present model simulations performed with the chemistry-climate model SOCOL, in which spatially disaggregated chemistry and transport tracers have been implemented in order to better understand the distribution and projected changes in tropospheric ozone. We examine the influences of ozone precursor emissions (nitrogen oxides (NOx), carbon monoxide (CO) and volatile organic compounds (VOCs)), climate change (including methane effects) and stratospheric ozone recovery on the tropospheric ozone budget, in a simulation following the climate scenario Representative Concentration Pathway (RCP) 6.0 (a medium-high, and reasonably realistic climate scenario). Changes in ozone precursor emissions have the largest effect, leading to a global-mean increase in tropospheric ozone which maximizes in the early 21st century at 23% compared to 1960. The increase is most pronounced at northern midlatitudes, due to regional emission patterns: between 1990 and 2060, northern midlatitude tropospheric ozone remains at constantly large abundances: 31% larger than in 1960. Over this 70-year period, attempts to reduce emissions in Europe and North America do not have an effect on zonally averaged northern midlatitude ozone because of increasing emissions from Asia, together with the long lifetime of ozone in the troposphere. A simulation with fixed anthropogenic ozone precursor emissions of NOx, CO and non-methane VOCs at 1960 conditions shows a 6% increase in global-mean tropospheric ozone by the end of the 21st century, with an 11 % increase at northern midlatitudes. This increase maximizes in the 2080s and is mostly caused by methane, which maximizes in the 2080s following RCP 6.0, and plays an important role in controlling ozone directly, and indirectly through its influence on other VOCs and CO. Enhanced flux of ozone from the stratosphere to the troposphere as well as climate change-induced enhancements in lightning NOx emissions also increase the tropospheric ozone burden, although their impacts are relatively small. Overall, the results show that under this climate scenario, ozone in the future is governed largely by changes in methane and NOx; methane induces an increase in tropospheric ozone that is approximately one-third of that caused by NOx. Climate impacts on ozone through changes in tropospheric temperature, humidity and lightning NOx remain secondary compared with emission strategies relating to anthropogenic emissions of NOx, such as fossil fuel burning. Therefore, emission policies globally have a critical role to play in determining tropospheric ozone evolution through the 21st century.

The Impact of Meteorology on Ozone Levels in the Lake Tahoe Basin

NASA Astrophysics Data System (ADS)

Theiss, Sandra

The Lake Tahoe Basin is located on the California-Nevada border and occasionally experiences elevated levels of ozone exceeding the 70 ppb California Air Resources Board (CARB) ambient air quality standard (8-hour average). Previous studies indicate that both the local generation of ozone in the Basin and long-range transport from out-of-Basin sources are important in contributing to ozone exceedances, but little is known about the impact of meteorology on the distribution of ozone source regions. In order to develop a better understanding of the factors affecting ozone levels and sources in the Lake Tahoe Basin, this study combines observational data from a 2010 and 2012 summer field campaigns, HYSPLIT back trajectories, and WRF model output to examine the meteorological influences of ozone transport in the topographically complex Lake Tahoe Basin. Findings from the field work portions of this study include enhanced background ozone levels at higher elevations, the local circulation pattern of lake breezes occurring at Lake level sites, and an indication that ozone precursors are coming off the Lake. Our analysis also showed that if transport of ozone does occur, it is more likely to come from the San Joaquin Valley to the south rather than originate in the large cities to the west, such as Sacramento and San Francisco. Analysis of modeled PBL schemes as compared with observational data showed that the ACM2 PBL scheme best represented the geographical domain. The ACM2 PBL scheme was then used to show wind circulation patterns in the Lake Tahoe Basin and concluded that there is decent vertical mixing over the Basin and no indication of ozone transport from the west however some indication of transport from the east. Overall this study concludes that transport from the west is less significant than transport from the south and east, and that transport only influences ozone values at higher elevations. Within the Basin itself (at lower elevations), local factors including mixing depth, rising or sinking air, and lake/land breeze circulations are more significant in influencing ozone values.

Ground-level Ozone (Smog) Information | New England | US ...

EPA Pesticide Factsheets

2017-09-05

Ground-level ozone presents a serious air quality problem in New England. In 2008, EPA revised the ozone standard to a level of 0.075 parts per million, 8-hour average. Over the last 5 years (2006 through 2010), there have been an average of 31 days per summer when New England's air exceeded this standard.

Critical levels as applied to ozone for North American forests

Treesearch

Robert C. Musselman

2006-01-01

The United States and Canada have used concentration-based parameters for air quality standards for ozone effects on forests in North America. The European critical levels method for air quality standards uses an exposure-based parameter, a cumulative ozone concentration index with a threshold cutoff value. The critical levels method has not been used in North America...

Airliner cabin ozone : an updated review.

DOT National Transportation Integrated Search

1989-12-01

The recent literature pertaining to ozone contamination of airliner cabins is reviewed. Measurements in airliner cabins without filters showed that ozone levels were about 50 percent of atmospheric ozone. Filters were about 90 percent effective in de...

Parameterizing the impacts of ozone-vegetation coupling and feedbacks on ozone air quality in a chemical transport model

NASA Astrophysics Data System (ADS)

Zhou, S.; Tai, A. P. K.; Lombardozzi, D.

2016-12-01

Apart from being an important greenhouse gas, tropospheric ozone is a significant air pollutant that is shown to have harmful effects both on human health and vegetation. Ozone damages vegetation mainly through reducing plant photosynthesis and stomatal conductance. Meanwhile, ozone is also strongly dependent on vegetation via various biogeochemical and physical processes. These interdependences between ozone and vegetation would constitute feedback mechanisms that can potentially alter ozone concentration itself, and should be considered in future climate and air quality projections. In this study, we first implement an empirical scheme for ozone damage on vegetation in the Community Land Model (CLM), and simulate the relative changes in leaf area indices (LAI) and stomatal conductance for three plant groups (consolidated from 15 plant functional types) at various prescribed ozone levels (from 0 ppb to 100 ppb). We find that all plant groups suffer the greatest decreases in LAI and stomatal conductance in regions with their greatest abundance, and grasses and crops show the most severe damage from ozone exposure compared with broadleaf and needleleaf groups, with an LAI reduction of as much as 50% in some areas even at an ozone level of 30 ppb. Using the CLM-simulated results, we develop a semi-empirical parameterization scheme to link prescribed ozone levels to the spatially varying simulated relative changes in LAI and stomatal conductance at model steady state. We implement the scheme in the GEOS-Chem chemical transport model so that ozone-vegetation chemical coupling via ozone dry deposition and biogenic volatile organic compound (VOC) emissions can be simulated online. Model simulations indicate that ozone effect on stomatal conductance (which modifies dry deposition) appears to be the dominant feedback pathway influencing surface ozone, whereas ozone-mediated LAI changes (which affects biogenic VOC emissions) appear to play a lesser role. This work is the first attempt to account for online ozone-vegetation coupling in a chemical transport model, with important ramifications for more realistic assessment of ozone air quality under a constantly evolving climate and land cover.

Consideration of air quality standards for vegetation with respect to ozone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heggestad, H.E.

1968-01-01

There is an increasing body of evidence that ozone is the most damaging of all air pollutants affecting vegetation. It is the principal oxidant in the photochemical smog complex. Concentrations measured with an ultraviolet photometer, considered specific for ozone, have exceeded 0.5 part per million (ppM) in the Los Angeles area. Only one-tenth of this level, or 0.05 ppM, for 8 hours is known to injure very sensitive tobacco varieties. Studies in several laboratories show that a broad spectrum of plant species is visibly affected after a few hours exposure at concentrations much lower than 0.5 ppM. There is alsomore » some evidence that ozone reduces plant growth. Many factors must be taken into account in considering standards for possible use in the protection of vegetation from ozone damage. These include ozone concentration and methods of measurement, time of exposure, possible additive effects of other pollutants, sensitivity of species to ozone, their economic value, and the extent of injury which can be tolerated. The response of a species to the pollutant is conditioned by genetic factors and environmental conditions. The lack of routine, specific methods for measuring ozone in ambient air is a handicap. California and Colorado established standards for oxidants at 0.15 ppM and 0.10 ppM, respectively, for 1 hour. How these standards relate to the dosage of ozone that causes acute and chronic injury to various plant species is discussed. 28 references.« less

Increased growth factors play a role in wound healing promoted by noninvasive oxygen-ozone therapy in diabetic patients with foot ulcers.

PubMed

Zhang, Jing; Guan, Meiping; Xie, Cuihua; Luo, Xiangrong; Zhang, Qian; Xue, Yaoming

2014-01-01

Management of diabetic foot ulcers (DFUs) is a great challenge for clinicians. Although the oxygen-ozone treatment improves the diabetic outcome, there are few clinical trials to verify the efficacy and illuminate the underlying mechanisms of oxygen-ozone treatment on DFUs. In the present study, a total of 50 type 2 diabetic patients complicated with DFUs, Wagner stage 2~4, were randomized into control group treated by standard therapy only and ozone group treated by standard therapy plus oxygen-ozone treatment. The therapeutic effects were graded into 4 levels from grade 0 (no change) to grade 3 (wound healing). The wound sizes were measured at baseline and day 20, respectively. Tissue biopsies were performed at baseline and day 11. The expressions of vascular endothelial growth factor (VEGF), transforming growth factor-β (TGF-β), and platelet-derived growth factor (PDGF) proteins in the pathologic specimens were determined by immunohistochemical examinations. The effective rate of ozone group was significantly higher than that of control group (92% versus 64%, P < 0.05). The wound size reduction was significantly more in ozone group than in control group (P < 0.001). After treatment, the expressions of VEGF, TGF-β, and PDGF proteins at day 11 were significantly higher in ozone group than in control group. Ozone therapy promotes the wound healing of DFUs via potential induction of VEGF, TGF-β, and PDGF at early stage of the treatment. (Clinical trial registry number is ChiCTR-TRC-14004415).

Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer

NASA Astrophysics Data System (ADS)

Monks, P. S.; Archibald, A. T.; Colette, A.; Cooper, O.; Coyle, M.; Derwent, R.; Fowler, D.; Granier, C.; Law, K. S.; Mills, G. E.; Stevenson, D. S.; Tarasova, O.; Thouret, V.; von Schneidemesser, E.; Sommariva, R.; Wild, O.; Williams, M. L.

2015-08-01

Ozone holds a certain fascination in atmospheric science. It is ubiquitous in the atmosphere, central to tropospheric oxidation chemistry, yet harmful to human and ecosystem health as well as being an important greenhouse gas. It is not emitted into the atmosphere but is a byproduct of the very oxidation chemistry it largely initiates. Much effort is focused on the reduction of surface levels of ozone owing to its health and vegetation impacts, but recent efforts to achieve reductions in exposure at a country scale have proved difficult to achieve owing to increases in background ozone at the zonal hemispheric scale. There is also a growing realisation that the role of ozone as a short-lived climate pollutant could be important in integrated air quality climate change mitigation. This review examines current understanding of the processes regulating tropospheric ozone at global to local scales from both measurements and models. It takes the view that knowledge across the scales is important for dealing with air quality and climate change in a synergistic manner. The review shows that there remain a number of clear challenges for ozone such as explaining surface trends, incorporating new chemical understanding, ozone-climate coupling, and a better assessment of impacts. There is a clear and present need to treat ozone across the range of scales, a transboundary issue, but with an emphasis on the hemispheric scales. New observational opportunities are offered both by satellites and small sensors that bridge the scales.

A modeling study of the impact of urban trees on ozone

Treesearch

David J. Nowak; Kevin L. Civerolo; S. Trivikrama Rao; Gopal Sistla; Christopher J. Luley; Daniel E. Crane

2000-01-01

Modeling the effects of increased urban tree cover on ozone concentrations (July 13-15, 1995) from Washington, DC, to central Massachusetts reveals that urban trees generally reduce ozone concentrations in cities, but tend to increase average ozone concentrations in the overall modeling domain. During the daytime, average ozone reductions in urban areas (1 ppb) were...

Results of the measurement of atmospheric ozone and hydrocarbons in Baden-Wurttemburg

NASA Technical Reports Server (NTRS)

Blander, W.; Siegel, D.

1978-01-01

Data are presented on the diurnal variations of the levels of ozone, ethylene, ethane, and acetylene. The measurement procedures used are described. Variations in monthly ozone levels are given, and measurements from different stations are compared. Data on the total monthly concentrations of NO and NO2 are compared with similar data for ozone. Problems in determining interrelationships among the concentrations of the various substances are discussed.

Solar photolysis of ozone to singlet D oxygen atoms

NASA Technical Reports Server (NTRS)

Blackburn, Thomas E.; Bairai, Solomon T.; Stedman, Donald H.

1992-01-01

The ground-level photolysis frequency of ozone J(O3) to produce metastable singlet D oxygen atoms (O (D-1)) is measured using a novel instrumental technique involving electrical conductivity. The O(D-1) atoms produced react with nitrous oxide (N2O) carrier gas to form higher oxides of nitrogen (NO(x)). These oxides were detected by mixing with methanol and determining the increase in electrical conductivity with a continuous-flow dual conductivity cell. Over 70 days of data were collected under varying sky conditions. The effect of temperature on J(O3) was measured. The results agree with model predictions. The effects of atmospheric aerosols, changes in overhead ozone column, and local cloudiness are discussed.

Inactivation of Escherichia coli by ozone treatment of apple juice at different pH levels.

PubMed

Patil, S; Valdramidis, V P; Cullen, P J; Frias, J; Bourke, P

2010-09-01

This research investigated the efficacy of gaseous ozone on the inactivation of Escherichia coli ATCC 25922 and NCTC 12900 strains in apple juice of a range of pH levels, using an ozone bubble column. The pH levels investigated were 3.0, 3.5, 4.0, 4.5 and 5.0. Apple juice inoculated with E. coli strains (10(6)CFU/mL) was treated with ozone gas at a flow rate of 0.12L/min and ozone concentration of 0.048 mg/min/mL for up to 18 min. Results show that inactivation kinetics of E. coli by ozone were affected by pH of the juice. The ozone treatment duration required for achieving a 5-log reduction was faster (4 min) at the lowest pH than at the highest pH (18 min) studied. The relationship between time required to achieve 5log reduction (t(5d)) and pH for both strains was described mathematically by two exponential equations. Ozone treatment appears to be an effective process for reducing bacteria in apple juice and the required applied treatment for producing a safe apple juice is dependant on its acidity level. Copyright 2010 Elsevier Ltd. All rights reserved.

NADPH:Quinone Oxidoreductase 1 Regulates Host Susceptibility to Ozone via Isoprostane Generation*

PubMed Central

Kummarapurugu, Apparao B.; Fischer, Bernard M.; Zheng, Shuo; Milne, Ginger L.; Ghio, Andrew J.; Potts-Kant, Erin N.; Foster, W. Michael; Soderblom, Erik J.; Dubois, Laura G.; Moseley, M. Arthur; Thompson, J. Will; Voynow, Judith A.

2013-01-01

NADPH:quinone oxidoreductase 1 (NQO1) is recognized as a major susceptibility gene for ozone-induced pulmonary toxicity. In the absence of NQO1 as can occur by genetic mutation, the human airway is protected from harmful effects of ozone. We recently reported that NQO1-null mice are protected from airway hyperresponsiveness and pulmonary inflammation following ozone exposure. However, NQO1 regenerates intracellular antioxidants and therefore should protect the individual from oxidative stress. To explain this paradox, we tested whether in the absence of NQO1 ozone exposure results in increased generation of A2-isoprostane, a cyclopentenone isoprostane that blunts inflammation. Using GC-MS, we found that NQO1-null mice had greater lung tissue levels of D2- and E2-isoprostanes, the precursors of J2- and A2-isoprostanes, both at base line and following ozone exposure compared with congenic wild-type mice. We confirmed in primary cultures of normal human bronchial epithelial cells that A2-isoprostane inhibited ozone-induced NF-κB activation and IL-8 regulation. Furthermore, we determined that A2-isoprostane covalently modified the active Cys179 domain in inhibitory κB kinase in the presence of ozone in vitro, thus establishing the biochemical basis for A2-isoprostane inhibition of NF-κB. Our results demonstrate that host factors may regulate pulmonary susceptibility to ozone by regulating the generation of A2-isoprostanes in the lung. These observations provide the biochemical basis for the epidemiologic observation that NQO1 regulates pulmonary susceptibility to ozone. PMID:23275341

Ozone profile measurements at McMurdo Station Antarctica during the spring of 1987

NASA Technical Reports Server (NTRS)

Hofmann, D. J.; Harder, J. W.; Rosen, J. M.; Hereford, J.; Carpenter, J. R.

1988-01-01

During the Antarctic spring of 1986, 33 ozone soundings were conducted from McMurdo Station. These data indicated that the springtime decrease in ozone occurred rapidly between the altitudes of 12 and 20 km. During 1987, these measurements were repeated with 50 soundings between 29 August and 9 November. Digital conversions of standard electrochemical cell ozonesondes were again employed. The ozonesonde pumps were individually calibrated for flow rate as the high altitude performance of these pumps have been in question. While these uncertainties are not large in the region of the ozone hole, they are significant at high altitude and apparently resulted in an underestimate of total ozone of about 7 percent (average) as compared to the Total Ozone Mapping Spectrometer (TOMS) in 1986, when the flow rate recommended by the manufacturer was used. At the upper altitudes (approx. 30 km) the flow rate may be overestimated by as much as 15 percent using recommended values (see Harder et al., The UW Digital Ozonesonde: Characteristics and Flow Rate Calibration, poster paper, this workshop). These upper level values are used in the extrapolation, at constant mixing ratio, required to complete the sounding for total ozone. The first sounding was on 29 August, prior to major ozone depletion, when 274 DU total ozone (25 DU extrapolated) was observed. By early October total ozone had decreased to the 150 DU range; it then increased during mid-October owing to motion of the vortex and returned to a value of 148 DU (29 DU extrapolated) on 27 October.

Measurements of the potential ozone production rate in a forest

NASA Astrophysics Data System (ADS)

Crilley, L.; Sklaveniti, S.; Kramer, L.; Bloss, W.; Flynn, J. H., III; Alvarez, S. L.; Erickson, M.; Dusanter, S.; Locoge, N.; Stevens, P. S.; Millet, D. B.; Alwe, H. D.

2017-12-01

Biogenic volatile organic compounds (BVOC) are a significant source of organic compounds globally and alongside NOx play a key role in the formation of ozone in the troposphere. Understanding how changes in NOx concentrations feed through to altered ozone production in BVOC dominated environments will aid our understanding of future atmospheric composition, notably as developing nations transition from NOx dominated to NOx limited chemistry as a result of mitigation strategies. Here we empirically investigate this ambient ozone formation potential. We report deployment of a custom built instrument to measure in near real time the potential for in situ chemical ozone production, using an artificial light source. Our results are thus indicative of the ozone formation potential for a sampled ambient air mixture, including full VOC complexity, i.e. independent of characterization of individual organic compounds. Ground level measurements were performed as part of the PROPHET-AMOS 2016 field campaign, at a site located within a Northern Michigan forest that has typically low NOx abundance, but high isoprene and terpenoid loadings. As the ambient NOx concentrations were low during the campaign, experiments were performed in which NO was artificially added to the sampled ambient air mixture, to quantify changes in the potential ozone production rate as a function of NOx, and hence the ozone forming characteristics of the ambient air. Preliminarily results from these experiments are presented, and indicate that while ozone production increases with added NO, significant variation was observed for a given NO addition, reflecting differences in the ambient VOC chemical reactivity and ozone formation tendency.

[The results of combined ozone therapy using in complex treatment of soft tissues infections in patients with diabetes mellitus type II].

PubMed

Vinnik, Iu S; Salmina, A B; Tepliakova, O V; Drobushevskaia, A I; Pozhilenkova, E A; Morgun, A V; Shapran, M V; Kovalenko, A O

2015-01-01

Levels of interleukins-6, 8, 10, TNF-alpha and basic fibroblast growth factor (bFGF) were examined in peripheral blood of 60 patients with diabetes mellitus type II and soft tissues infections. It was revealed the elevated levels of proinflammatory (IL-6, 8), anti-inflammatory (IL-10) cytokines and basic fibroblast growth factor at the time of admission. Application of combined ozone therapy including ozonated autohemotherapy and superficial management of wounds with ozone-oxygen mixture resulted in significant decrease of IL-6, 8, 10 production and high level of bFGF on blood serum. Thus effective local bactericidal impact of ozone in combination with normalization of proinflammatory cytokines levels and preserved high level of bFGF in peripheral blood provide better results of wound healing process in patients with diabetes mellitus type II.

Study nonlinear dynamics of stratospheric ozone concentration at Pakistan Terrestrial region

NASA Astrophysics Data System (ADS)

Jan, Bulbul; Zai, Muhammad Ayub Khan Yousuf; Afradi, Faisal Khan; Aziz, Zohaib

2018-03-01

This study investigates the nonlinear dynamics of the stratospheric ozone layer at Pakistan atmospheric region. Ozone considered now the most important issue in the world because of its diverse effects on earth biosphere, including human health, ecosystem, marine life, agriculture yield and climate change. Therefore, this paper deals with total monthly time series data of stratospheric ozone over the Pakistan atmospheric region from 1970 to 2013. Two approaches, basic statistical analysis and Fractal dimension (D) have adapted to study the nature of nonlinear dynamics of stratospheric ozone level. Results obtained from this research have shown that the Hurst exponent values of both methods of fractal dimension revealed an anti-persistent behavior (negatively correlated), i.e. decreasing trend for all lags and Rescaled range analysis is more appropriate as compared to Detrended fluctuation analysis. For seasonal time series all month follows an anti-persistent behavior except in the month of November which shown persistence behavior i.e. time series is an independent and increasing trend. The normality test statistics also confirmed the nonlinear behavior of ozone and the rejection of hypothesis indicates the strong evidence of the complexity of data. This study will be useful to the researchers working in the same field in the future to verify the complex nature of stratospheric ozone.

Photo-Fenton-assisted ozonation of p-Coumaric acid in aqueous solution.

PubMed

Monteagudo, J M; Carmona, M; Durán, A

2005-08-01

The degradation of p-Coumaric acid present in olive oil mill wastewater was investigated as a pretreatment stage to obtain more easily biodegradable molecules, with lower toxicity that facilitates subsequent anaerobic digestion. Thus, photo-Fenton-assisted ozonation has been studied and compared with ozonation at alkaline pH and conventional single ultraviolet (UV) and acid ozonation treatments. In the combined process, the overall kinetic rate constant was split into various components: direct oxidation by UV light, direct oxidation by ozone and oxidation by hydroxyl radicals. Molecular and/or radical ozone reaction was studied by conducting the reaction in the presence and absence of tert-butylalcohol at pHs 2, 7 and 9. Ozone oxidation rate increases with pH or by the addition of Fenton reagent and/or UV radiation due to generation of hydroxyl radicals, *OH. Hydrogen peroxide and ferrous ion play a double role during oxidation since at low concentrations they act as initiators of hydroxyl radicals but at high concentrations they act as radical scavengers. Finally, the additional levels of degradation by formation of hydroxyl radicals have been quantified in comparison to the conventional single processes and an equation is proposed for the reaction rate as a function of studied operating variables.

VOC Reactivity and the Ozone Climate Penalty: Modeled Impacts of Updated Aromatic and Monoterpene Chemistry on the Ozone-temperature Connection

NASA Astrophysics Data System (ADS)

Porter, W. C.; Heald, C. L.; Safieddine, S.

2016-12-01

Rising temperatures associated with global warming can increase concentrations of tropospheric ozone (O3) in many regions worldwide, a correlation often described as the "ozone climate penalty". This effect is driven by a variety of underlying chemical, physical, and biological mechanisms, including temperature-dependent reaction rates, emissions of volatile organic compounds (VOCs) from trees and other plant life, and correlations with other meteorological variables. While many of the most important O3-producing VOCs, such as isoprene, are represented in typical chemical transport models such as GEOS-Chem, others - including aromatics from fires and human activity and monoterpenes from natural sources - are not always included in gas-phase chemistry. Here we examine the impact of increased VOC reactivity on the ozone climate penalty due to a more comprehensive treatment of aromatics and monoterpenes in the chemical transport model GEOS-Chem, finding regional impacts not only on daily O3 levels themselves, but also on the O3/temperature relationship. While many uncertainties related to the emissions and chemistry of these species remain, the impact of their inclusion on both current simulations and future projections indicates their importance towards the overall goal of more accurately modeled surface O3.

Photocatalytic ozonation of urban wastewater and surface water using immobilized TiO2 with LEDs: Micropollutants, antibiotic resistance genes and estrogenic activity.

PubMed

Moreira, Nuno F F; Sousa, José M; Macedo, Gonçalo; Ribeiro, Ana R; Barreiros, Luisa; Pedrosa, Marta; Faria, Joaquim L; Pereira, M Fernando R; Castro-Silva, Sérgio; Segundo, Marcela A; Manaia, Célia M; Nunes, Olga C; Silva, Adrián M T

2016-05-01

Photocatalytic ozonation was employed for the first time in continuous mode with TiO2-coated glass Raschig rings and light emitting diodes (LEDs) to treat urban wastewater as well as surface water collected from the supply area of a drinking water treatment plant (DWTP). Different levels of contamination and types of contaminants were considered in this work, including chemical priority substances (PSs) and contaminants of emerging concern (CECs), as well as potential human opportunistic antibiotic resistant bacteria and their genes (ARB&ARG). Photocatalytic ozonation was more effective than single ozonation (or even than TiO2 catalytic ozonation) in the degradation of typical reaction by-products (such as oxalic acid), and more effective than photocatalysis to remove the parent micropollutants determined in urban wastewater. In fact, only fluoxetine, clarithromycin, erythromycin and 17-alpha-ethinylestradiol (EE2) were detected after photocatalytic ozonation, by using solid-phase extraction (SPE) pre-concentration and LC-MS/MS analysis. In surface water, this treatment allowed the removal of all determined micropollutants to levels below the limit of detection (0.01-0.20 ng L(-1)). The efficiency of this process was then assessed based on the capacity to remove different groups of cultivable microorganisms and housekeeping (16S rRNA) and antibiotic resistance or related genes (intI1, blaTEM, qnrS, sul1). Photocatalytic ozonation was observed to efficiently remove microorganisms and ARGs. Although after storage total heterotrophic and ARB (to ciprofloxacin, gentamicin, meropenem), fungi, and the genes 16S rRNA and intI1, increased to values close to the pre-treatment levels, the ARGs (blaTEM, qnrS and sul1) were reduced to levels below/close to the quantification limit even after 3-days storage of treated surface water or wastewater. Yeast estrogen screen (YES), thiazolyl blue tetrazolium reduction (MTT) and lactate dehydrogenase (LDH) assays were also performed before and after photocatalytic ozonation to evaluate the potential estrogenic activity, the cellular metabolic activity and the cell viability. Compounds with estrogenic effects and significant differences concerning cell viability were not observed in any case. A slight cytotoxicity was only detected for Caco-2 and hCMEC/D3 cell lines after treatment of the urban wastewater, but not for L929 fibroblasts. Copyright © 2016 Elsevier Ltd. All rights reserved.

Current ozone levels threaten gross primary production and yield of Mediterranean annual pastures and nitrogen modulates the response

NASA Astrophysics Data System (ADS)

Calvete-Sogo, Héctor; Elvira, Susana; Sanz, Javier; González-Fernández, Ignacio; García-Gómez, Héctor; Sánchez-Martín, Laura; Alonso, Rocío; Bermejo-Bermejo, Victoria

2014-10-01

Pastures are among the most important ecosystems in Europe considering their biodiversity and distribution area. However, their response to increasing tropospheric ozone (O3) and nitrogen (N) deposition, two of the main drivers of global change, is still uncertain. A new Open-Top Chamber (OTC) experiment was performed in central Spain, aiming to study annual pasture response to O3 and N in close to natural growing conditions. A mixture of six species of three representative families was sowed in the field. Plants were exposed for 40 days to four O3 treatments: filtered air, non-filtered air (NFA) reproducing ambient levels and NFA supplemented with 20 and 40 nl l-1 O3. Three N treatments were considered to reach the N integrated doses of “background”, +20 or +40 kg N ha-1. Ozone significantly reduced green and total aboveground biomass (maximum reduction 25%) and increased the senescent biomass (maximum increase 40%). Accordingly, O3 decreased community Gross Primary Production due to both a global reduction of ecosystem CO2 exchange and an increase of ecosystem respiration. Nitrogen could partially counterbalance O3 effects on aboveground biomass when the levels of O3 were moderate, but at the same time O3 exposure reduced the fertilization effect of higher N availability. Therefore, O3 must be considered as a stress factor for annual pastures in the Mediterranean areas.

Terrestrial nitrous oxide cycles and atmospheric effects

NASA Technical Reports Server (NTRS)

Whitten, R. C.; Lawless, J. G.; Banin, A.

1984-01-01

The basic processes that cause N2O emission from soils are briefly discussed, and the rate of the processes is shown to vary widely in space and time, depending on soil, climate, and agrotechnical conditions. Although significant amounts of N2O are indeed emitted from the land, the complexity of the soil processes involved and the wide variation of measured rates still prevents the quantitative evaluation, global budgeting, and reliable prediction of atmospheric N2O. Increased atmospheric N2O abundance increases the levels of odd-nitrogen in the stratosphere, which, in turn, decreases the stratospheric ozone density via a catalytic cycle. Using appropriate atmospheric models and current chemical kinetic data, it has been found that the dependence of ozone reduction on N2O increase is nearly linear; a simulated doubling of N2O leads to a predicted decrease of about 14 percent in total ozone column density. A 10 percent increase in N2O yields a predicted increase in nonmelanoma skin cancer of several percent, and a possible raising of surface temperature of 0.03 K.

Effects of ultraviolet radiation and contaminant-related stressors on arctic freshwater ecosystems.

PubMed

Wrona, Frederick J; Prowse, Terry D; Reist, James D; Hobbie, John E; Lévesque, Lucie M J; Macdonald, Robie W; Vincent, Warwick F

2006-11-01

Climate change is likely to act as a multiple stressor, leading to cumulative and/or synergistic impacts on aquatic systems. Projected increases in temperature and corresponding alterations in precipitation regimes will enhance contaminant influxes to aquatic systems, and independently increase the susceptibility of aquatic organisms to contaminant exposure and effects. The consequences for the biota will in most cases be additive (cumulative) and multiplicative (synergistic). The overall result will be higher contaminant loads and biomagnification in aquatic ecosystems. Changes in stratospheric ozone and corresponding ultraviolet radiation regimes are also expected to produce cumulative and/or synergistic effects on aquatic ecosystem structure and function. Reduced ice cover is likely to have a much greater effect on underwater UV radiation exposure than the projected levels of stratospheric ozone depletion. A major increase in UV radiation levels will cause enhanced damage to organisms (biomolecular, cellular, and physiological damage, and alterations in species composition). Allocations of energy and resources by aquatic biota to UV radiation protection will increase, probably decreasing trophic-level productivity. Elemental fluxes will increase via photochemical pathways.

North Atlantic Oscillation and pollutants variability in Europe: model analysis and measurements intercomparison

NASA Astrophysics Data System (ADS)

Pausata, F.; Pozzoli, L.; Van Dingenen, R.; Vignati, E.; Cavalli, F.; Dentener, F. J.

2013-12-01

Ozone pollution and particulate matter (PM) represent a serious health and environmental problem. While ozone pollution is mostly produced by photochemistry in summer, PM is of main concern during winter. Both pollutants can be influenced nt only by local scale processes but also by long range transport driven by the atmospheric circulation and stratospheric ozone intrusions. We analyze the role of large scale atmospheric circulation variability in the North Atlantic basin in determining surface ozone and PM concentrations over Europe. Here, we show, using ground station measurements and a coupled atmosphere-chemistry model simulation for the period 1980-2005, that with regard to ozone the North Atlantic Oscillation (NAO) does affect surface ozone concentrations - on a monthly timescale, over 10 ppbv in southwestern, central and northern Europe - during all seasons except fall. We find that the first Principal Component, computed from the time variation of the sea level pressure (SLP) field, detects the atmosphere circulation/ozone relationship not only in winter and spring but also during summer, when the atmospheric circulation weakens and regional photochemical processes peak. Given the NAO forecasting skill at intraseasonal time scale, the first Principal Component of the SLP field could be used as an indicator to identify areas more exposed to forthcoming ozone pollution events. Finally, our results suggest that the increasing baseline ozone in western and northern Europe during the 1990s could be related to the prevailing positive phase of the NAO in that period. With regard to PM, our study shows that in winter the NAO modulates surface PM concentrations accounting in average up to 30% of the total PM variability. During positive NAO phases, positive PM anomalies occur over southern Europe, and negative anomalies in central-northern Europe. A positve shift of the NAO mean states, hence, leads to an increase in cardiac and resipratory morbidity related to PM exposure in the Mediterranean countries with up to over 5000 more deaths per 20 million people for a 2000 emission inventory.

Comparison of NASA OMI and MLS Ozone Products with US Forest Service Ground-based Ozone Monitoring Data for US Forest Service Air Quality / Forest Management Decision Support

NASA Astrophysics Data System (ADS)

Barrett, S.; Brooks, A.; Moussa, Y.; Spencer, T.; Thompson, J.

2013-12-01

Tropospheric ozone, formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs) react with sunlight, is a significant threat to the health of US National Forests. Approximately one third of ozone is absorbed by plants during the uptake of carbon dioxide. This increases the vegetation's susceptibility to drought, beetle infestation, and wildfire. Currently the US Forest Service has ground monitoring stations sparsely located across the country. This project looks specifically at the area surrounding several Class I Wilderness Areas in the Appalachian region. These areas are the highest priority for protection from air pollutants. The Forest Service must interpolate ozone concentrations for areas between these monitoring stations. Class I Wilderness Areas are designated by the Forest Service and are defined as a total 5000 acres or greater when the Clean Air Act was passed in 1977. This Act mandated that the EPA create national ambient air quality standards (NAAQS) for six major air pollutants including ground-level ozone. This project assessed the feasibility of incorporating NASA ozone data into Forest Service ozone monitoring in an effort to enhance the accuracy and precision of ozone exposure measurements in Class I Wilderness Areas and other federally managed lands in order to aid in complying with the Clean Air Act of 1977. This was accomplished by establishing a method of comparison between a preliminary data product produced at the Goddard Space Flight Center that uses OMI/MLS data to derive global tropospheric ozone measurements and Forest Service ozone monitoring station measurements. Once a methodology for comparison was established, statistical comparisons of these data were performed to assess the quantitative differences.

Ozone induces glucose intolerance and systemic metabolic effects in young and aged brown Norway rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bass, V.; Gordon, C.J.; Jarema, K.A.

Air pollutants have been associated with increased diabetes in humans. We hypothesized that ozone would impair glucose homeostasis by altering insulin signaling and/or endoplasmic reticular (ER) stress in young and aged rats. One, 4, 12, and 24 month old Brown Norway (BN) rats were exposed to air or ozone, 0.25 or 1.0 ppm, 6 h/day for 2 days (acute) or 2 d/week for 13 weeks (subchronic). Additionally, 4 month old rats were exposed to air or 1.0 ppm ozone, 6 h/day for 1 or 2 days (time-course). Glucose tolerance tests (GTT) were performed immediately after exposure. Serum and tissue biomarkersmore » were analyzed 18 h after final ozone for acute and subchronic studies, and immediately after each day of exposure in the time-course study. Age-related glucose intolerance and increases in metabolic biomarkers were apparent at baseline. Acute ozone caused hyperglycemia and glucose intolerance in rats of all ages. Ozone-induced glucose intolerance was reduced in rats exposed for 13 weeks. Acute, but not subchronic ozone increased α{sub 2}-macroglobulin, adiponectin and osteopontin. Time-course analysis indicated glucose intolerance at days 1 and 2 (2 > 1), and a recovery 18 h post ozone. Leptin increased day 1 and epinephrine at all times after ozone. Ozone tended to decrease phosphorylated insulin receptor substrate-1 in liver and adipose tissues. ER stress appeared to be the consequence of ozone induced acute metabolic impairment since transcriptional markers of ER stress increased only after 2 days of ozone. In conclusion, acute ozone exposure induces marked systemic metabolic impairments in BN rats of all ages, likely through sympathetic stimulation. - Highlights: • Air pollutants have been associated with increased diabetes in humans. • Acute ozone exposure produces profound metabolic alterations in rats. • Age influences metabolic risk factors in aging BN rats. • Acute metabolic effects are reversible and repeated exposure reduces these effects. • Ozone metabolic effects are only slightly exacerbated in geriatric rats.« less

Ozone in the marine boundary layer of Bay of Bengal and Arabian Sea during post winter period - continental influence

NASA Astrophysics Data System (ADS)

Nair, Prabha R.; George, Susan K.; David, Liji Mary; Parameswaran, Krishnaswamy

Ozone plays a key role in controlling the oxidation capacity of the troposphere and hence the lifetime of a variety of trace gases in the atmosphere. In pristine marine boundary layer (MBL), entire chemistry is initiated by the photolysis of ozone and the subsequent formation of OH radical from water vapour. Also in such environment, photochemical destruction is considered as a major sink in global ozone budget. Even though large number of studies on near surface ozone has been carried out over land such studies are very few over oceanic environments. This paper presents the observational results on the spatial variations of near-surface ozone over Bay of Bengal and Arabian Sea as revealed by the cruise-based measurements (cruise No. SK223) conducted as part of Integrated Campaign for Aerosol gases and Radiation Budget (ICARB) under the Geosphere Biosphere Programme of Indian Space Research Organisation (IGBP). Online measurements of ozone have been carried out by using a UV Photometric Analyser (model 49C of Thermo Electron Corporation, USA). Ozone mixing ratio was observed to be significantly high over northern Bay of Bengal (20-28 ppb) compared to southern Bay of Bengal and Arabian Sea. Minimum levels of ozone ( 5 ppb) have been measured in the central Bay of Bengal region. Over Arabian Sea latitudinal variation was not prominently observed. The over all latitudinal gradient is estimated to be 1.2 ppb/o latitude over Bay of Bengal with longitudinal gradient showing variation depending on the latitude sector. It was maximum (of 1.2ppb/o longitude) over the mid Bay of Bengal region ( 15o N). Longitudinal variation was not significant over northern and southern regions. A close examination of surface airflow patterns and the air mass back trajectories revealed increase in ozone level associated with continental outflow from the northern and central parts of the subcontinent. The diurnal pattern also showed variations depending on the proximity to inhabited land mass and also with meteorological parameters.

Climate Response to the Increase in Tropospheric Ozone since Preindustrial Times: A Comparison between Ozone and Equivalent CO2 Forcings

NASA Technical Reports Server (NTRS)

Mickley L. J.; Jacob, D. J.; Field, B. D.; Rind, D.

2004-01-01

We examine the characteristics of the climate response to anthropogenic changes in tropospheric ozone. Using a general circulation model, we have carried out a pair of equilibrium climate simulations with realistic present-day and preindustrial ozone distributions. We find that the instantaneous radiative forcing of 0.49 W m(sup -2) due to the increase in tropospheric ozone since preindustrial times results in an increase in global mean surface temperature of 0.28 C. The increase is nearly 0.4 C in the Northern Hemisphere and about 0.2 C in the Southern Hemisphere. The largest increases (greater than 0.8 C) are downwind of Europe and Asia and over the North American interior in summer. In the lower stratosphere, global mean temperatures decrease by about 0.2 C due to the diminished upward flux of radiation at 9.6 micrometers. The largest stratospheric cooling, up to 1.0 C, occurs over high northern latitudes in winter, with possibly important implications for the formation of polar stratospheric clouds. To identify the characteristics of climate forcing unique to tropospheric ozone, we have conducted two additional climate equilibrium simulations: one in which preindustrial tropospheric ozone concentrations were increased everywhere by 18 ppb, producing the same global radiative forcing as present-day ozone but without the heterogeneity; and one in which CO2 was decreased by 25 ppm relative to present day, with ozone at present-day values, to again produce the same global radiative forcing but with the spectral signature of CO2 rather than ozone. In the first simulation (uniform increase of ozone), the global mean surface temperature increases by 0.25 C, with an interhemispheric difference of only 0.03 C, as compared with nearly 0.2 C for the heterogeneous ozone increase. In the second simulation (equivalent CO2), the global mean surface temperature increases by 0.36 C, 30% higher than the increase from tropospheric ozone. The stronger surface warming from CO2 is in part because CO2 forcing (obscured by water vapor) is shifted relatively poleward where the positive ice-albedo feedback amplifies the climate response and in part because the magnitude of the CO2 forcing in the mid-troposphere is double that of ozone. However, we find that CO2 is far less effective than tropospheric ozone in driving lower stratospheric cooling at high northern latitudes in winter.

An Update of the Bodeker Scientific Vertically Resolved, Global, Gap-Free Ozone Database

NASA Astrophysics Data System (ADS)

Kremser, S.; Bodeker, G. E.; Lewis, J.; Hassler, B.

2016-12-01

High vertical resolution ozone measurements from multiple satellite-based instruments have been merged with measurements from the global ozonesonde network to calculate monthly mean ozone values in 5º latitude zones. Ozone number densities and ozone mixing ratios are provided on 70 altitude levels (1 to 70 km) and on 70 pressure levels spaced approximately 1 km apart (878.4 hPa to 0.046 hPa). These data are sparse and do not cover the entire globe or altitude range. To provide a gap-free database, a least squares regression model is fitted to these data and then evaluated globally. By applying a single fit at each level, and using the approach of allowing the regression fits to change only slightly from one level to the next, the regression is less sensitive to measurement anomalies at individual stations or to individual satellite-based instruments. Particular attention is paid to ensuring that the low ozone abundances in the polar regions are captured. This presentation reports on updates to an earlier version of the vertically resolved ozone database, including the incorporation of new ozone measurements and new techniques for combining the data. Compared to previous versions of the database, particular attention is paid to avoiding spatial and temporal sampling biases and tracing uncertainties through to the final product. This updated database, developed within the New Zealand Deep South National Science Challenge, is suitable for assessing ozone fields from chemistry-climate model simulations or for providing the ozone boundary conditions for global climate model simulations that do not treat stratospheric chemistry interactively.

Surface ozone measurements in the southwest of the Iberian Peninsula (Huelva, Spain).

PubMed

Carnero, Jose A Adame; Bolívar, Juan P; de la Morena, Benito A

2010-02-01

Photochemical ozone pollution of the lower troposphere (LT) is a very complex process involving meteorological, topographic emissions and chemical parameters. Ozone is considered the most important air pollutant in rural, suburban and industrial areas of many sites in the world since it strongly affects human health, vegetation and forest ecosystems, and its increase during the last decades has been significant. In addition, ozone is a greenhouse gas that contributes to climate change. For these reasons, it is necessary to carry out investigations that determine the behaviour of ozone at different locations. The aim of this work is to understand the levels and temporal variations of surface ozone in an industrial-urban region of the Southwest Iberian Peninsula. The study is based on ozone hourly data recorded during a 6-year period, 2000 to 2005 at four stations and meteorological data from a coastal station. The stations used were El Arenosillo and Cartaya--both coastal stations, Huelva--an urban site and Valverde--an inland station 50 km away from the coastline. The general characteristics of the ozone series, seasonal and daily ozone cycles as well as number of exceedances of the threshold established in the European Ozone Directive have been calculated and analysed. Analysis of the meteorological data shows that winter-autumn seasons are governed by the movement of synoptic weather systems; however, in the spring-summer seasons, both synoptic and mesoescale conditions exist. Average hourly ozone concentrations range from 78.5 +/- 0.1 microg m(-3) at Valverde to 57.8 +/- 0.2 microg m(-3) at Huelva. Ozone concentrations present a seasonal variability with higher values in summer months, while in wintertime, lower values are recorded. A seasonal daily evolution has also been found with minimum levels around 08:00 UTC, which occurs approximately 1-1.5 h after sunrise, whereas the maximum is reached at about 16:00 UTC. Furthermore, during summer, the maximum value at El Arenosillo and Valverde stations remains very uniformed until 20:00 UTC. These levels could be due to the photochemical production in situ and also to the horizontal and vertical ozone transport at El Arenosillo from the reservoir layers in the sea and in the case of Valverde, the horizontal transport, thanks to the marine breeze. Finally, the data have been evaluated relative to the thresholds defined in the European Ozone Directive. The threshold to protect human health has been exceeded during the spring and summer months mainly at El Arenosillo and Valverde. The vegetation threshold has also been frequently exceeded, ranging from 131 days at Cartaya up to 266 days at Valverde. The results in the seasonal and daily variations demonstrate that El Arenosillo and Valverde stations show higher ozone concentrations than Cartaya and Huelva during the spring and summer months. Under meteorological conditions characterized by land-sea breeze circulation, the daytime sea breeze transports the emissions from urban and industrial sources in the SW further inland. Under this condition, the area located downwind to the NE is affected very easily by high ozone concentrations, which is the case for the Valverde station. Nevertheless, according to this circulation model, the El Arenosillo station located at the coast SE from these sources is not directly affected by their emissions. The ozone concentrations observed at El Arenosillo can be explained by the ozone residual layer over the sea, similar to other coastal sites in the Mediterranean basin. The temporal variations of the ozone concentrations have been studied at four measurement sites in the southwest of the Iberian Peninsula. The results obtained point out that industrial and urban emissions combined with specific meteorological conditions in spring and summer cause high ozone levels which exceed the recommended threshold limits and could affect the vegetation and human health in this area. This work is the first investigation related to surface ozone in this region; therefore, the results obtained may be a useful tool to air quality managers and policy-makers to apply possible air control strategies towards a reduction of ozone exceedances and the impact on human health and vegetation. Due to the levels, variability and underlying boundary layer dynamics, it is necessary to extend this research in this geographical area with the purpose of improving the understanding of photochemical air pollution in the Western Mediterranean Basin and in the south of the Iberian Peninsula.

Linear operating region in the ozone dial photon counting system

NASA Technical Reports Server (NTRS)

Andrawis, Madeleine

1995-01-01

Ozone is a relatively unstable molecule found in Earth's atmosphere. An ozone molecule is made up of three atoms of oxygen. Depending on where ozone resides, it can protect or harm life on Earth. High in the atmosphere, about 15 miles up, ozone acts as a shield to protect Earth's surface from the sun's harmful ultraviolet radiation. Without this shield, we would be more susceptible to skin cancer, cataracts, and impaired immune systems. Closer to Earth, in the air we breathe, ozone is a harmful pollutant that causes damage to lung tissue and plants. Since the early 1980's, airborne lidar systems have been used for making measurements of ozone. The differential absorption lidar (DIAL) technique is used in the remote measurement of O3. This system allows the O3 to be measured as function of the range in the atmosphere. Two frequency-doubled Nd:YAG lasers are used to pump tunable dye lasers. The lasers are operating at 289 nm for the DIAL on-line wavelength of O3, and the other one is operated at 300 nm for the off-line wavelength. The DIAL wavelengths are produced in sequential laser pulses with a time separation of 300 micro s. The backscattered laser energy is collected by telescopes and measured using photon counting systems. The photon counting system measures the light signal by making use of the photon nature of light. The output pulse from the Photo-Multiplier Tube (PE), caused by a photon striking the PMT photo-cathode, is amplified and passed to a pulse height discriminator. The peak value of the pulse is compared to a reference voltage (discrimination level). If the pulse amplitude exceeds the discrimination level, the discriminator generates a standard pulse which is counted by the digital counter. Non-linearity in the system is caused by the overlapping of pulses and the finite response time of the electronics. At low count rates one expects the system to register one event for each output pulse from the PMT corresponding to a photon incident upon the photocathode, however, at higher rates the limitations of the discrimination/counting system will cause the observed count rate to be non-linear with respect to the true count rate. Depending on the pulse height distribution and the discriminator level, the overlapping of pulses (pulse pile-up) can cause count loss or even an additional apparent count gain as the signal levels increase. Characterization of the system, including the pulse height distribution, the signal to noise ratio, and the effect of the discriminator threshold level, is critical in maximizing the linear operating region of the system, thus greatly increasing the useful dynamic range of the system.

Rat lung metallothionein and heme oxygenase gene expression following ozone and zinc oxide exposure.

PubMed

Cosma, G; Fulton, H; DeFeo, T; Gordon, T

1992-11-01

We have conducted exposures in rats to determine pulmonary responses following inhalation of two common components of welding fumes, zinc oxide and ozone. To examine their effects on target-inducible gene expression, we measured mRNA levels of two metal-responsive genes, metallothionein (MT) and heme oxygenase (HO), in lung tissue by RNA slot-blot analysis. A 3-hr exposure to ZnO fume via a combustion furnace caused a substantial elevation in lung MT mRNA at all concentrations tested. Exposures to 5 and 2.5 mg/m3 ZnO resulted in peak 8-fold increases in MT mRNA levels (compared to air-exposed control animal values) immediately after exposure, while 1 mg/m3 ZnO exposure caused a 3.5-fold elevation in MT mRNA. These levels returned to approximate control gene expression values 24 hr after exposure. In addition, ZnO exposure caused an immediate elevation in lung HO gene expression levels, with 8-, 11-, and 5-fold increases observed after the same ZnO exposure levels (p < 0.05). Like MT gene induction, HO mRNA values returned to approximate control levels 24 hr after exposure. In striking contrast to the induction of MT and HO gene expression after ZnO exposures, there was no elevation in gene expression following a 6-hr exposure to 0.5 and 1 ppm ozone, even when lungs were examined as late as 72 hr after exposure. Our results demonstrate the induction of target gene expression following the inhalation of ZnO at concentrations equal to, and below, the current recommended threshold limit value of 5 mg/m3 ZnO. Furthermore, the lack of effect of ozone exposure on MT and HO gene expression suggests no involvement of these genes in the acute respiratory response to this oxidant compound.

Rapid vertical trace gas transport by an isolated midlatitude thunderstorm

NASA Astrophysics Data System (ADS)

Hauf, Thomas; Schulte, Peter; Alheit, Reiner; Schlager, Hans

1995-11-01

During the cloud dynamics and chemistry field experiment CLEOPATRA in the summer of 1992 in southern Germany, the Deutsche Forschungsanstalt für Luft- und Raumfahrt (DLR) (German Aerospace Research Establishment) research aircraft Falcon traversed four times the anvil of a severe, isolated thunderstorm. The first two traverses were at 8 km altitude and close to the anvil cloud base, while the second two traverses were at 10 km. During the 8-km traverse, measured ozone mixing ratios dropped by 13 parts per billion by volume (ppbv) from the ambient cloud free environment to the anvil cloud, while water vapor increased by 0.3 g kg-1. At the 10-km traverses, ozone dropped by 25 ppbv, while water vapor increased by 0.18 g kg-1. Three-dimensional numerical thunderstorm simulations were performed to understand the cause of these changes. The simulations included the transport of two chemical inert tracers. Ozone was assumed to be one of them. The initial ozone profile was composed from an ozone routine sounding and the in situ Falcon measurements prior to the thunderstorm development. The second tracer is typical for a surface released pollutant with a nonzero, constant value in the boundary layer but zero above it. The redistribution of both tracers by the storm is calculated and compared with the observations. For the anvil penetration at 10 km, the calculated difference in ozone mixing ratios is 21 ppbv, while for water vapor an increase of 0.25 g kg-1 was found, in good agreement with the observations. To validate the model results, the radar reflectivity was calculated from simulated fields of cloud water, rain, graupel, hail, and snow and ice crystals and compared with observed values. With respect to maximum reflectivity values and spatial scales, again, excellent agreement was achieved. It is concluded that the rapid transport from the boundary layer directly into the anvil level is the most likely cause of the observed ozone decrease and water vapor increase. Entrainment of ozone-rich environmental air into the anvil cloud occurred but left a protected core with undiluted boundary layer air in the anvil cloud even at a distance of 120 km from the main updraft. Processes such as production of O3 by electrical discharges, chemical reactions of ozone with boundary layer-released or lightning-produced nitrogen compounds, scavenging by hydrometeors, and heterogeneous reactions at the surface of ice crystals may occur, but on the timescale of 0.5-1 hour seem to have a negligible influence on the observed ozone drop.

Impact of Cabin Ozone Concentrations on Passenger Reported Symptoms in Commercial Aircraft

PubMed Central

Bekö, Gabriel; Allen, Joseph G.; Weschler, Charles J.; Vallarino, Jose; Spengler, John D.

2015-01-01

Due to elevated ozone concentrations at high altitudes, the adverse effect of ozone on air quality, human perception and health may be more pronounced in aircraft cabins. The association between ozone and passenger-reported symptoms has not been investigated under real conditions since smoking was banned on aircraft and ozone converters became more common. Indoor environmental parameters were measured at cruising altitude on 83 US domestic and international flights. Passengers completed a questionnaire about symptoms and satisfaction with the indoor air quality. Average ozone concentrations were relatively low (median: 9.5 ppb). On thirteen flights (16%) ozone levels exceeded 60 ppb, while the highest peak level reached 256 ppb for a single flight. The most commonly reported symptoms were dry mouth or lips (26%), dry eyes (22.1%) and nasal stuffiness (18.9%). 46% of passengers reported at least one symptom related to the eyes or mouth. A third of the passengers reported at least one upper respiratory symptom. Using multivariate logistic (individual symptoms) and linear (aggregated continuous symptom variables) regression, ozone was consistently associated with symptoms related to the eyes and certain upper respiratory endpoints. A concentration-response relationship was observed for nasal stuffiness and eye and upper respiratory symptom indicators. Average ozone levels, as opposed to peak concentrations, exhibited slightly weaker associations. Medium and long duration flights were significantly associated with more symptoms compared to short flights. The relationship between ultrafine particles and ozone on flights without meal service was indicative of ozone-initiated chemistry. PMID:26011001

Regulatory Impact Analysis of the Final Revisions to the National Ambient Air Quality Standards for Ground-Level Ozone

EPA Pesticide Factsheets

The EPA performed an illustrative analysis of the potential costs, human health benefits, and welfare benefits of nationally attaining a revised primary ozone standard of 70 ppb and a primary alternative ozone standard level of 65 ppb.

The total ozone and UV solar radiation over Stara Zagora, Bulgaria

NASA Astrophysics Data System (ADS)

Mendeva, B. D.; Gogosheva, Ts. N.; Petkov, B. H.; Krastev, D. G.

The results from direct ground-based solar UV irradiance measurements and the total ozone content (TOC) over Stara Zagora (42° 25'N, 25° 37'E), Bulgaria are presented. During the period 1999-2003 the TOC data show seasonal variations, typical for the middle latitudes - maximum in the spring and minimum in the autumn. The comparison between TOC ground-based data and Global Ozone Monitoring Experiment (GOME) satellite-borne ones shows a seasonal dependence of the differences between them. A strong negative relationship between the total ozone and the 305 nm wavelength irradiance was found. The dependence between the two variables is significant ( r = -0.62 ± 0.18) at 98% confidence level. The direct sun UV doses for some specific biological effects (erythema and eyes) are obtained. The estimation of the radiation amplification factor RAF shows that the ozone reduction by 1% increases the erythemal dose by 2.3%. The eye-damaging doses are more influenced by the TOC changes and in this case RAF = -2.7%. The amount of these biological doses depended on the solar altitude over the horizon. This dependence was not so strong when the total ozone content in the atmosphere was lower.

An Overview of the Uintah Basin Winter Ozone Study Intensives: 2012, 2013, and 2014

NASA Astrophysics Data System (ADS)

Roberts, J. M.; Edwards, P. M.; Brown, S. S.; Ahmadov, R.; Bates, T. S.; De Gouw, J. A.; Gilman, J.; Graus, M.; Helmig, D.; Koss, A.; Langford, A. O.; Lefer, B. L.; Lerner, B. M.; Li, R.; Li, S. M.; Liggio, J.; McKeen, S. A.; McLaren, R.; Parrish, D. D.; Quinn, P.; Senff, C. J.; Stutz, J.; Thompson, C. R.; Tsai, J. Y.; Veres, P. R.; Washenfelder, R. A.; Warneke, C.; Wild, R. J.; Young, C.; Yuan, B.

2014-12-01

Ground level ozone frequently exceeds the National Ambient Air Quality Standard in the Uintah Basin in northeastern Utah during the winter season. The basin is home to some of the most intensive oil and gas production in the region, activities that have been accelerated by new technologies in that industry. High ozone episodes are coincident with the presence of snow and "cold pool" conditions during which a stable shallow boundary layer persists for periods of up to 10 days. Local emissions of NOx and VOCs build up within this layer, but the sources of radicals that initiate the photochemistry have been unclear since low photolysis rates and water vapor make the traditional channel, ozone photolysis, quite inefficient. Intensive studies over the past 3 winter seasons have shown that unconventional radical sources; primarily carbonyls, and to a lesser extent nitryl chloride and nitrous acid, are responsible for radical production in this environment. The role of snow cover is to restrict vertical mixing, enhance photolysis rates through increased albedo, and reduce ozone deposition. The uptake and production of photo-labile species on the snow surface were observed, but appear to have only minor influences on the ozone photochemistry.

Long-term trends of surface ozone and its influencing factors at the Mt Waliguan GAW station, China - Part 2: The roles of anthropogenic emissions and climate variability

NASA Astrophysics Data System (ADS)

Xu, Wanyun; Xu, Xiaobin; Lin, Meiyun; Lin, Weili; Tarasick, David; Tang, Jie; Ma, Jianzhong; Zheng, Xiangdong

2018-01-01

Inter-annual variability and long-term trends in tropospheric ozone are both environmental and climate concerns. Ozone measured at Mt Waliguan Observatory (WLG, 3816 m a.s.l.) on the Tibetan Plateau over the period of 1994-2013 has increased significantly by 0.2-0.3 ppbv yr-1 during spring and autumn but shows a much smaller trend in winter and no significant trend in summer. Here we explore the factors driving the observed ozone changes at WLG using backward trajectory analysis, chemistry-climate model hindcast simulations (GFDL AM3), a trajectory-mapped ozonesonde data set, and several climate indices. A stratospheric ozone tracer implemented in GFDL AM3 indicates that stratosphere-to-troposphere transport (STT) can explain ˜ 60 % of the simulated springtime ozone increase at WLG, consistent with an increase in the NW air-mass frequency inferred from the trajectory analysis. Enhanced STT associated with the strengthening of the mid-latitude jet stream contributes to the observed high ozone anomalies at WLG during the springs of 1999 and 2012. During autumn, observations at WLG are more heavily influenced by polluted air masses originating from South East Asia than in the other seasons. Rising Asian anthropogenic emissions of ozone precursors are the key driver of increasing autumnal ozone observed at WLG, as supported by the GFDL AM3 model with time-varying emissions, which captures the observed ozone increase (0.26 ± 0.11 ppbv yr-1). AM3 simulates a greater ozone increase of 0.38 ± 0.11 ppbv yr-1 at WLG in autumn under conditions with strong transport from South East Asia and shows no significant ozone trend in autumn when anthropogenic emissions are held constant in time. During summer, WLG is mostly influenced by easterly air masses, but these trajectories do not extend to the polluted regions of eastern China and have decreased significantly over the last 2 decades, which likely explains why summertime ozone measured at WLG shows no significant trend despite ozone increases in eastern China. Analysis of the Trajectory-mapped Ozonesonde data set for the Stratosphere and Troposphere (TOST) and trajectory residence time reveals increases in direct ozone transport from the eastern sector during autumn, which adds to the autumnal ozone increase. We further examine the links of ozone variability at WLG to the quasi-biennial oscillation (QBO), the East Asian summer monsoon (EASM), and the sunspot cycle. Our results suggest that the 2-3-, 3-7-, and 11-year periodicities are linked to the QBO, EASM index, and sunspot cycle, respectively. A multivariate regression analysis is performed to quantify the relative contributions of various factors to surface ozone concentrations at WLG. Through an observational and modelling analysis, this study demonstrates the complex relationships between surface ozone at remote locations and its dynamical and chemical influencing factors.

Stratospheric cooling and polar ozone loss due to H2 emissions of a global hydrogen economy

NASA Astrophysics Data System (ADS)

Feck, T.; Grooß, J.-U.; Riese, M.; Vogel, B.

2009-04-01

"Green" hydrogen is seen as a major element of the future energy supply to reduce greenhouse gas emissions substantially. However, due to the possible interactions of hydrogen (H2) with other atmospheric constituents there is a need to analyse the implications of additional atmospheric H2 that could result from hydrogen leakage of a global hydrogen infrastructure. Emissions of molecular H2 can occur along the whole hydrogen process chain which increase the tropospheric H2 burden. Across the tropical tropopause H2 reaches the stratosphere where it is oxidised and forms water vapour (H2O). This causes increased IR-emissions into space and hence a cooling of the stratosphere. Both effects, the increase of stratospheric H2O and the cooling, enhances the potential of chlorine activation on liquid sulfate aerosol and polar stratospheric clouds (PSCs), which increase polar ozone destruction. Hence a global hydrogen economy could provoke polar ozone loss and could lead to a substantial delay of the current projected recovery of the stratospheric ozone layer. Our investigations show that even if 90% of the current global fossil primary energy input could be replaced by hydrogen and approximately 9.5% of the product gas would leak to the atmosphere, the ozone loss would be increased between 15 to 26 Dobson Units (DU) if the stratospheric CFC loading would retain unchanged. A consistency check of the used approximation methods with the Chemical Lagrangian Model of the Stratosphere (CLaMS) shows that this additional ozone loss can probably be treated as an upper limit. Towards more realistic future H2 leakage rate assumptions (< 3%) the additional ozone loss would be rather small (? 10 DU). However, in all cases the full damage would only occur if stratospheric CFC-levels would retain unchanged. Due to the CFC-prohibition as a result of the Montreal Protocol the forecasts suggest a decline of the stratospheric CFC loading about 50% until 2050. In this case our calculations show that the addition effect would account for only less than 4 DU which is equivalent to 1% of the current unperturbed ozone layer over the polar regions (? 400 DU). Hence the risk of a substantial damage to the stratospheric ozone layer due to H2-emissions of a hydrogen economy is low compared to the positive climate implications that would evolve from the avoidance of greenhouse gas emissions.

Reconciliation of Halogen-Induced Ozone Loss with the Total-Column Ozone Record

NASA Technical Reports Server (NTRS)

Shepherd, T. G.; Plummer, D. A.; Scinocca, J. F.; Hegglin, M. I.; Fioletov, V. E.; Reader, M. C.; Remsberg, E.; von Clarmann, T.; Wang, H. J.

2014-01-01

The observed depletion of the ozone layer from the 1980s onwards is attributed to halogen source gases emitted by human activities. However, the precision of this attribution is complicated by year-to-year variations in meteorology, that is, dynamical variability, and by changes in tropospheric ozone concentrations. As such, key aspects of the total-column ozone record, which combines changes in both tropospheric and stratospheric ozone, remain unexplained, such as the apparent absence of a decline in total-column ozone levels before 1980, and of any long-term decline in total-column ozone levels in the tropics. Here we use a chemistry-climate model to estimate changes in halogen-induced ozone loss between 1960 and 2010; the model is constrained by observed meteorology to remove the eects of dynamical variability, and driven by emissions of tropospheric ozone precursors to separate out changes in tropospheric ozone. We show that halogen-induced ozone loss closely followed stratospheric halogen loading over the studied period. Pronounced enhancements in ozone loss were apparent in both hemispheres following the volcanic eruptions of El Chichon and, in particular, Mount Pinatubo, which significantly enhanced stratospheric aerosol loads. We further show that approximately 40% of the long-term non-volcanic ozone loss occurred before 1980, and that long-term ozone loss also occurred in the tropical stratosphere. Finally, we show that halogeninduced ozone loss has declined by over 10% since stratospheric halogen loading peaked in the late 1990s, indicating that the recovery of the ozone layer is well underway.

Chemical and climatic drivers of radiative forcing due to changes in stratospheric and tropospheric ozone over the 21st century

NASA Astrophysics Data System (ADS)

Banerjee, Antara; Maycock, Amanda C.; Pyle, John A.

2018-02-01

The ozone radiative forcings (RFs) resulting from projected changes in climate, ozone-depleting substances (ODSs), non-methane ozone precursor emissions and methane between the years 2000 and 2100 are calculated using simulations from the UM-UKCA chemistry-climate model (UK Met Office's Unified Model containing the United Kingdom Chemistry and Aerosols sub-model). Projected measures to improve air-quality through reductions in non-methane tropospheric ozone precursor emissions present a co-benefit for climate, with a net global mean ozone RF of -0.09 W m-2. This is opposed by a positive ozone RF of 0.05 W m-2 due to future decreases in ODSs, which is driven by an increase in tropospheric ozone through stratosphere-to-troposphere transport of air containing higher ozone amounts. An increase in methane abundance by more than a factor of 2 (as projected by the RCP8.5 scenario) is found to drive an ozone RF of 0.18 W m-2, which would greatly outweigh the climate benefits of non-methane tropospheric ozone precursor reductions. A small fraction (˜ 15 %) of the ozone RF due to the projected increase in methane results from increases in stratospheric ozone. The sign of the ozone RF due to future changes in climate (including the radiative effects of greenhouse gases, sea surface temperatures and sea ice changes) is shown to be dependent on the greenhouse gas emissions pathway, with a positive RF (0.05 W m-2) for RCP4.5 and a negative RF (-0.07 W m-2) for the RCP8.5 scenario. This dependence arises mainly from differences in the contribution to RF from stratospheric ozone changes. Considering the increases in tropopause height under climate change causes only small differences (≤ |0.02| W m-2) for the stratospheric, tropospheric and whole-atmosphere RFs.

Formation of N-nitrosodimethylamine (NDMA) by ozonation of dyes and related compounds.

PubMed

Oya, Masami; Kosaka, Koji; Asami, Mari; Kunikane, Shoichi

2008-12-01

Formation of N-nitrosodimethylamine (NDMA) by ozonation of commercially available dyes and related compounds was investigated. Ozonation was conducted using a semi-batch type reactor, and ozone concentration in gas phase and the ozone gas flow were 10 mg L(-1) and 1.0 L min(-1), respectively. NDMA was formed by 15 min of ozonation of seven out of eight selected target compounds (0.05 mM) at pH 7. All the target compounds with N,N-dimethylamino functions were NDMA precursors in ozonation. The lowest and highest NDMA concentrations after ozonation of the target compounds were 13 ng L(-1) for N,N-dimethylformamide (DMF) and 1600 ng L(-1) for N,N-dimethyl-p-phenylenediamine (DMPD), respectively. NDMA concentrations after 15 min of ozonation of 0.05 mM methylene blue (MB) and DMPD increased with an increase in pH in its range of 6-8. The effects of coexisting compounds on NDMA concentrations after 15 min of ozonation of 0.05 mM MB and DMPD were examined at pH 7. NDMA concentrations after ozonation of MB and DMPD increased by the presence of 0.05 mM (0.7 mg L(-1) as N) nitrite (NO(2)(-)); 5000 ng L(-1) for MB and 4000 ng L(-1) for DMPD. NDMA concentration after MB ozonation decreased by the presence of 5mM tertiary butyl alcohol (TBA), a hydroxyl radical (HO.) scavenger, but that after DMPD ozonation was increased by the presence of TBA. NDMA concentrations after ozonation of MB and DMPD were not affected by the presence of 0.16 mM (5.3 mg L(-1)) hydrogen peroxide (H(2)O(2)). When 0.05 mM MB and DMPD were added to the Yodo and Tone river water samples, NDMA concentrations after 15 min of their ozonation at pH 7 increased compared with those in the case of addition to ultrapure water samples.

Detoxification of zearalenone and ochratoxin A by ozone and quality evaluation of ozonised corn.

PubMed

Qi, Lijun; Li, Yulin; Luo, Xiaohu; Wang, Ren; Zheng, Ruihang; Wang, Li; Li, Yongfu; Yang, Dan; Fang, Wenmiao; Chen, Zhengxing

2016-11-01

Zearalenone (ZEN) and ochratoxin A (OTA) are secondary toxic metabolites of fungi that can contaminate a wide range of food and feedstuff. In this study, the effects of ozone treatment on ZEN and OTA and the quality of ozonised corn are investigated. Ozone significantly affects ZEN and OTA solutions. ZEN was undetectable 5 s after being treated with 10 mg l -1 ozone. However, OTA was resistant to ozonation with a degradation rate of 65.4% after 120 s of treatment. Moreover, ZEN and OTA solutions were difficult to degrade after being dried by a nitrogen stream. Results showed that ozone effectively degraded ZEN and OTA in corn. The degradation rates of ZEN and OTA in corn increased with ozone concentration and treatment time. The degradation of ZEN and OTA at different ozone concentrations appropriately conformed to first-order kinetics with an R 2 value > 0.8749. Furthermore, under the same conditions, corn with increased moisture content (MC) (19.6%) was more sensitive to ozone than corn with a low MC (14.1%). When treated with 100 mg l -1 ozone for 180 min, ZEN and OTA in corn with 19.6% MC decreased by 90.7% and 70.7%, respectively. To evaluate the quality of ozonised corn, subsequent quality experiments were conducted using corn samples treated at different times with 100 mg l -1 ozone. The MC of corn decreased after ozone treatment. The whiteness and yellowness of the corn increased and decreased with increasing time, respectively. The fatty acid value of the corn increased significantly (p ≤ 0.05) after 180 min of treatment. This study verified that ozone can effectively degrade ZEN and OTA in corn, but slightly affected corn quality.

The microbial killing capacity of aqueous and gaseous ozone on different surfaces contaminated with dairy cattle manure

PubMed Central

Lowe, James

2018-01-01

A high reactivity and leaving no harmful residues make ozone an effective disinfectant for farm hygiene and biosecurity. Our objectives were therefore to (1) characterize the killing capacity of aqueous and gaseous ozone at different operational conditions on dairy cattle manure-based pathogens (MBP) contaminated different surfaces (plastic, metal, nylon, rubber, and wood); (2) determine the effect of microbial load on the killing capacity of aqueous ozone. In a crossover design, 14 strips of each material were randomly assigned into 3 groups, treatment (n = 6), positive-control (n = 6), and negative-control (n = 2). The strips were soaked in dairy cattle manure with an inoculum level of 107–108 for 60 minutes. The treatment strips were exposed to aqueous ozone of 2, 4, and 9 ppm and gaseous ozone of 1and 9 ppm for 2, 4, and 8 minutes exposure. 3M™ Petrifilm™ rapid aerobic count plate and plate reader were used for bacterial culture. On smooth surfaces, plastic and metal, aqueous ozone at 4 ppm reduced MBP to a safe level (≥5-log10) within 2 minutes (6.1 and 5.1-log10, respectively). However, gaseous ozone at 9 ppm for 4 minutes inactivated 3.3-log10 of MBP. Aqueous ozone of 9 ppm is sufficient to reduce MBP to a safe level, 6.0 and 5.4- log10, on nylon and rubber surfaces within 2 and 8 minutes, respectively. On complex surfaces, wood, both aqueous and gaseous ozone at up to 9 ppm were unable to reduce MBP to a safe level (3.6 and 0.8-log10, respectively). The bacterial load was a strong predictor for reduction in MBP (P<0.0001, R2 = 0.72). We conclude that aqueous ozone of 4 and 9 ppm for 2 minutes may provide an efficient method to reduce MBP to a safe level on smooth and moderately rough surfaces, respectively. However, ozone alone may not an adequate means of controlling MBP on complex surfaces. PMID:29758045

Regional trend analysis of surface ozone observations from monitoring networks in eastern North America, Europe and East Asia

NASA Astrophysics Data System (ADS)

Chang, K. L.; Petropavlovskikh, I. V.; Cooper, O. R.; Schultz, M.; Wang, T.

2017-12-01

Surface ozone is a greenhouse gas and pollutant detrimental to human health and crop and ecosystem productivity. The Tropospheric Ozone Assessment Report (TOAR) is designed to provide the research community with an up-to-date observation-based overview of tropospheric ozone's global distribution and trends. The TOAR Surface Ozone Database contains ozone metrics at thousands of monitoring sites around the world, densely clustered across mid-latitude North America, western Europe and East Asia. Calculating regional ozone trends across these locations is challenging due to the uneven spacing of the monitoring sites across urban and rural areas. To meet this challenge we conducted a spatial and temporal trend analysis of several TOAR ozone metrics across these three regions for summertime (April-September) 2000-2014, using the generalized additive mixed model (GAMM). Our analysis indicates that East Asia has the greatest human and plant exposure to ozone pollution among investigating regions, with increasing ozone levels through 2014. The results also show that ozone mixing ratios continue to decline significantly over eastern North America and Europe, however, there is less evidence for decreases of daytime average ozone at urban sites. The present-day spatial coverage of ozone monitors in East Asia (South Korea and Japan) and eastern North America is adequate for estimating regional trends by simply taking the average of the individual trends at each site. However the European network is more sparsely populated across its northern and eastern regions and therefore a simple average of the individual trends at each site does not yield an accurate regional trend. This analysis demonstrates that the GAMM technique can be used to assess the regional representativeness of existing monitoring networks, indicating those networks for which a regional trend can be obtained by simply averaging the trends of all individual sites and those networks that require a more sophisticated statistical approach.

A flux-based assessment of above and below ground biomass of Holm oak (Quercus ilex L.) seedlings after one season of exposure to high ozone concentrations

NASA Astrophysics Data System (ADS)

Gerosa, Giacomo; Fusaro, Lina; Monga, Robert; Finco, Angelo; Fares, Silvano; Manes, Fausto; Marzuoli, Riccardo

2015-07-01

Young plants of Holm oak (Quercus ilex) were exposed in non-limiting water conditions to four different levels of ozone (O3) concentrations in Open-Top Chambers during one growing season to evaluate biomass losses on roots, stems and leaves in relation to O3 exposure (AOT40) and phytotoxical ozone dose (POD1) absorbed. The exposure-effect and dose-effect relationships for the total biomass were statistically significant and indicated a reduction of 4% and 5.2% of the total biomass for each increase step of 10000 ppb h of AOT40 and 10 mmol m-2 of POD1, respectively. The results indicate a critical level for Holm oak protection of 7 mmol m-2 of POD1, which corresponds to 4% of total biomass reduction. The linear regressions based on the POD1 were significant for roots and stem biomass losses, but not significant for leaf biomass. The biomass loss rate at increasing POD1 was higher for roots than for stems and leaves, suggesting that stem growth under high levels of O3 is less affected than root growth. Because of the scarcity of data from the Mediterranean area, these results can be relevant for the O3 risk assessment models and for the definition of new O3 critical levels for forests in Europe.

Association of short-term increases in ambient air pollution and timing of initial asthma diagnosis among Medicaid-enrolled children in a metropolitan area.

PubMed

Wendt, Judy K; Symanski, Elaine; Stock, Thomas H; Chan, Wenyaw; Du, Xianglin L

2014-05-01

We investigated associations of short-term changes in ambient ozone (O3), fine particulate matter (PM2.5) and nitrogen dioxide (NO2) concentrations and the timing of new-onset asthma, using a large, high-risk population in an area with historically high ozone levels. The study population included 18,289 incident asthma cases identified among Medicaid-enrolled children in Harris County Texas between 2005-2007, using Medicaid Analytic Extract enrollment and claims files. We used a time-stratified case-crossover design and conditional logistic regression to assess the effect of increased short-term pollutant concentrations on the timing of asthma onset. Each 10 ppb increase in ozone was significantly associated with new-onset asthma during the warm season (May-October), with the strongest association seen when a 6-day cumulative average period was used as the exposure metric (odds ratio [OR]=1.05, 95% confidence interval [CI], 1.02-1.08). Similar results were seen for NO2 and PM2.5 (OR=1.07, 95% CI, 1.03-1.11 and OR=1.12, 95% CI, 1.03-1.22, respectively), and PM2.5 also had significant effects in the cold season (November-April), 5-day cumulative lag (OR=1.11. 95% CI, 1.00-1.22). Significantly increased ORs for O3 and NO2 during the warm season persisted in co-pollutant models including PM2.5. Race and age at diagnosis modified associations between ozone and onset of asthma. Our results indicate that among children in this low-income urban population who developed asthma, their initial date of diagnosis was more likely to occur following periods of higher short-term ambient pollutant levels. Copyright © 2014 Elsevier Inc. All rights reserved.

Maternal exposure to ozone and PM2.5 and the prevalence of orofacial clefts in four U.S. states

PubMed Central

Zhou, Ying; Gilboa, Suzanne M.; Herdt, Michele L.; Lupo, Philip J.; Flanders, W. Dana; Liu, Yang; Shin, Mikyong; Canfield, Mark A.; Kirby, Russell S.

2017-01-01

Background While there is some evidence that maternal exposure to ambient air pollution is associated with orofacial clefts in offspring, the epidemiologic studies have been largely equivocal. We evaluated whether maternal exposure to elevated county-level ambient fine particulate matter with aerodynamic diameter ≤2.5 μm (PM2.5) and ozone during early gestation was associated with a higher prevalence of orofacial clefts. Methods Birth data consisting of 4.7 million births from 2001 to 2007 were obtained from National Birth Defects Prevention Network for four states — Arizona, Florida, New York (excluding New York City), and Texas. The air pollution exposure assessment for gestational weeks 5–10 was based on county-level average concentrations of PM2.5 and ozone data generated using a Bayesian fusion model available through CDC's Environmental Public Health Tracking Network. Two outcomes were analyzed separately: cleft lip with or without cleft palate, cleft palate alone. In logistic regression analyses, we adjusted for factors that were suspected confounders or modifiers of the association between the prevalence of orofacial clefts and air pollution, i.e., infant sex, race-ethnicity, maternal education, smoking status during pregnancy, whether this was mother's first baby, maternal age. Results Each 10 μg/m3 increase in PM2.5 concentration was significantly associated with cleft palate alone (OR =1.43, 95% CI: 1.11–1.86). There was no significant association between PM2.5 concentration and cleft lip with or without cleft palate. No associations were observed between ozone exposure and the two outcomes of orofacial clefts. Conclusions Our study suggests that PM2.5 significantly increased the risk of cleft palate alone, but did not change the incidence of cleft lip with or without palate. Ozone levels did not correlate with incidence of orofacial clefts. PMID:27888746

A study of surface ozone variability over the Iberian Peninsula during the last fifty years

NASA Astrophysics Data System (ADS)

Fernández-Fernández, M. I.; Gallego, M. C.; García, J. A.; Acero, F. J.

2011-02-01

There is good evidence for an increase in the global surface level of ozone in the past century. In this work we present an analysis of 18 surface ozone series over the Iberian Peninsula, considering the target values of ozone for the protection of human health and for the protection of vegetation, as well as the information and alert thresholds established by the current European Directive on ambient air quality and cleaner air for Europe (Directive 2008/50/EC). The results show that the stations located on the Cantabrian coast exceeded neither the target value for the protection of human health nor the target value for the protection of vegetation. The information threshold was exceeded in most of the stations, while the alert threshold was only exceeded in one. The seasonal and daily evolution of ozone concentrations were as expected. A trend analysis of three surface ozone concentration indices (monthly median and 98th percentile, and monthly maximum of the daily maximum 8-h mean) was performed both for the whole period of each station and for the common period from 2001 to 2007 for all the months of the year. It was noted that generally the south of the Iberian Peninsula presented increasing trends for the three indices, especially in the last six months of the year, and the north decreasing trends. Finally, a correlation analysis was performed between the daily maximum 8-h mean and both daily mean temperature and daily mean solar radiation for the whole and the common periods. For all stations, there was a significant positive association at a 5% significance level between the daily maximum 8-h mean and the two meteorological variables of up to approximately 0.5. The spatial distribution of these association values from 2001 to 2007 showed a positive northwest to southeast gradient over the Iberian Peninsula.

Measurements of in situ chemical ozone (oxidant) production rates

NASA Astrophysics Data System (ADS)

Huang, Hao; Faloon, Kate; Najera, Juan; Bloss, William

2013-04-01

Tropospheric ozone is a major air pollutant, harmful to human health, agricultural crops and vegetation, the main precursor to the atmospheric oxidants which initiate the degradation of most reactive gases emitted to the atmosphere, and an important greenhouse gas in its own right. The capacity to understand and predict tropospheric ozone levels is a key goal for atmospheric science - but one which is challenging, as ozone is formed in the atmosphere from the complex oxidation of VOCs in the presence of NOx and sunlight, on a timescale such that in situ chemical processes, deposition and transport all affect ozone levels. Known uncertainties in emissions, chemistry, dynamics and deposition affect the accuracy of predictions of current and future ozone levels, and hinder development of optimal air quality policies to mitigate against ozone exposure. Recently new approaches to directly measure the local chemical ozone production rate, bypassing the many uncertainties in emissions and chemical schemes, have been developed (Cazorla & Brune, AMT 2010). Here, we describe the development of an analogous Ozone Production Rate (OPR) approach: Air is sampled into parallel reactors, within which ozone formation either occurs as in the ambient atmosphere, or is suppressed. Comparisons of ozone levels exiting a pair of such reactors determines the net chemical oxidant production rate, after correction for perturbation of the NOx-O3 photochemical steady state, and when operated under conditions such that wall effects are minimised. We report preliminary measurements of local chemical ozone production made during the UK NERC ClearfLo (Clean Air for London) campaign at an urban background location in London in January and July 2012. The OPR system was used to measure the local chemical oxidant formation rate, which is compared with observed trends in O3 and NOx and the prevailing meteorology, and with the predictions of a detailed zero-dimensional atmospheric chemistry model, constrained by observations of long-lived species.

ACUTE OZONE-INDUCED INFLAMMATORY GENE EXPRESSION IN THE RAT LUNG IS NOT RELATED TO LEVELS OF ANTIOXIDANTS IN THE LAVAGE FLUID

EPA Science Inventory

ABSTRACT BODY: Ozone causes oxidative stress and lung inflammation. We hypothesized that rat strains with or without genetic susceptibility to cardiovascular disease will have different antioxidant levels in alveolar lining, and that ozone induced inflammatory gene expression wil...

INTERANNUAL VARIATION IN METEOROLOGICALLY ADJUSTED OZONE LEVELS IN THE EASTERN UNITED STATES: A COMPARISON OF TWO APPROACHED

EPA Science Inventory

Assessing the influence of abatement efforts and other human activities on ozone levels is complicated by the atmosphere's changeable nature. Two statistical methods, the dynamic linear model(DLM) and the generalized additive model (GAM), are used to estimate ozone trends in the...

OZONE OVER SAN FRANCISCO. MEANS AND PATTERNS DURING POLLUTION EPISODES

EPA Science Inventory

Measurements of meteorological parameters were taken at six levels and ozone at four levels between 260m and 473m ASL on the Mt. Sutro T.V. Tower in San Francisco during the summers of 1974 through 1976. Hourly average ozone concentrations within the elevated inversion layer at t...

Traffic congestion and ozone precursor emissions in Bilbao, Spain.

PubMed

Ibarra-Berastegi, Gabriel; Madariaga, Imanol

2003-01-01

In urban environments, the measured levels of ozone are the result of the interaction between emissions of precursors (mainly VOCs and NOx) and meteorological effects. In this work, time series of daily values of ozone, measured at three locations in Bilbao (Spain), have been built. Then, after removing meteorological effects from them, ozone and traffic data have been analyzed jointly. The goal was to identify traffic situations and link them to ozone levels in the area of Bilbao. To remove meteorological effects from the selected ozone time series, the technique developed by Rao and Zurbenko was used. This is a widely used technique and, after its application, the fraction obtained from a given ozone time series represents an ozone forming capability attributable to emissions of precursors. This fraction is devoid of any meteorological influence and includes only the apportion of periodicities above 1.7 years. In the case of Bilbao, the ozone fractions obtained at three locations have been compared on that time scale with traffic data from the area. For the 1993-1996 period, a regression analysis of the ozone and traffic fractions due to periodicities above 1.7 years (long-term fractions), shows that traffic is the main explanatory factor for ozone with R2 ranging from 0.916 to 0.996 at the three locations studied. Analysis of these longterm fractions has made it possible to identify two traffic regimes for the whole area, associated to different profiles of ozone forming capability. The first one favors low ozone forming capability, and is associated with a situation of fluent traffic. The second one shows high ozone forming capability and represents congestion. Joint analysis of raw data of ozone and traffic do not show any clear pattern due to the strong masking effects that seasonal-meteorological effects (mainly radiation) have on the measured ozone signal. If only immission data of ozone are available, as in this case, a comparison between ozone and traffic can only be made on the long-term time scale, since that is the only fraction embedded in the ozone time series that can exclusively be attributed to emissions of precursors. This fact stresses the need to study the different fractions embedded in the time series of ozone measured levels separately. Though the coefficients obtained in the regression are only valid for the 1993-1996 period, these traffic regimes represent long-term targets (congestion or fluent traffic) that can inspire policies for a joint management of the traffic and pollution by ozone in the area of Bilbao beyond that period. The results of this work show the need of a joint management of ozone and traffic in Bilbao. Since an accurate knowledge of traffic was not available, the use of emission factors to relate traffic and actual ozone levels has not been possible. For this reason, this study has focused on the long-term fractions of traffic and ozone. In the future, if a more accurate knowledge of traffic is available, it will be possible to find relationships between traffic and ozone on all time scales.

The impact of surfactant protein-A on ozone-induced changes in the mouse bronchoalveolar lavage proteome

PubMed Central

2009-01-01

Background Ozone is a major component of air pollution. Exposure to this powerful oxidizing agent can cause or exacerbate many lung conditions, especially those involving innate immunity. Surfactant protein-A (SP-A) plays many roles in innate immunity by participating directly in host defense as it exerts opsonin function, or indirectly via its ability to regulate alveolar macrophages and other innate immune cells. The mechanism(s) responsible for ozone-induced pathophysiology, while likely related to oxidative stress, are not well understood. Methods We employed 2-dimensional difference gel electrophoresis (2D-DIGE), a discovery proteomics approach, coupled with MALDI-ToF/ToF to compare the bronchoalveolar lavage (BAL) proteomes in wild type (WT) and SP-A knockout (KO) mice and to assess the impact of ozone or filtered air on the expression of BAL proteins. Using the PANTHER database and the published literature most identified proteins were placed into three functional groups. Results We identified 66 proteins and focused our analysis on these proteins. Many of them fell into three categories: defense and immunity; redox regulation; and protein metabolism, modification and chaperones. In response to the oxidative stress of acute ozone exposure (2 ppm; 3 hours) there were many significant changes in levels of expression of proteins in these groups. Most of the proteins in the redox group were decreased, the proteins involved in protein metabolism increased, and roughly equal numbers of increases and decreases were seen in the defense and immunity group. Responses between WT and KO mice were similar in many respects. However, the percent change was consistently greater in the KO mice and there were more changes that achieved statistical significance in the KO mice, with levels of expression in filtered air-exposed KO mice being closer to ozone-exposed WT mice than to filtered air-exposed WT mice. Conclusion We postulate that SP-A plays a role in reactive oxidant scavenging in WT mice and that its absence in the KO mice in the presence or absence of ozone exposure results in more pronounced, and presumably chronic, oxidative stress. PMID:19323824

Fugitive Emissions from the Bakken Shale Illustrate Role of Shale Production in Global Ethane Shift

NASA Technical Reports Server (NTRS)

Kort, E. A.; Smith, M. L.; Murray, L. T.; Gvakharia, A.; Brandt, A. R.; Peischl, J.; Ryerson, T. B.; Sweeney, C.; Travis, K.

2016-01-01

Ethane is the second most abundant atmospheric hydrocarbon, exerts a strong influence on tropospheric ozone, and reduces the atmosphere's oxidative capacity. Global observations showed declining ethane abundances from 1984 to 2010, while a regional measurement indicated increasing levels since 2009, with the reason for this subject to speculation. The Bakken shale is an oil and gas-producing formation centered in North Dakota that experienced a rapid increase in production beginning in 2010. We use airborne data collected over the North Dakota portion of the Bakken shale in 2014 to calculate ethane emissions of 0.23 +/- 0.07 (2 sigma) Tg/yr, equivalent to 1-3% of total global sources. Emissions of this magnitude impact air quality via concurrent increases in tropospheric ozone. This recently developed large ethane source from one location illustrates the key role of shale oil and gas production in rising global ethane levels.

Associations of daily pediatric asthma emergency department visits with air pollution in Newark, NJ: utilizing time-series and case-crossover study designs.

PubMed

Gleason, Jessie A; Fagliano, Jerald A

2015-10-01

Asthma is one of the most common chronic diseases affecting children. This study assesses the associations of ozone and fine particulate matter (PM2.5) with pediatric emergency department visits in the urban environment of Newark, NJ. Two study designs were utilized and evaluated for usability. We obtained daily emergency department visits among children aged 3-17 years with a primary diagnosis of asthma during April to September for 2004-2007. Both a time-stratified case-crossover study design with bi-directional control sampling and a time-series study design were utilized. Lagged effects (1-d through 5-d lag, 3-d average, and 5-d average) of ozone and PM2.5 were explored and a dose-response analysis comparing the bottom 5th percentile of 3-d average lag ozone with each 5 percentile increase was performed. Associations of interquartile range increase in same-day ozone were similar between the time-series and case-crossover study designs (RR = 1.08, 95% CI 1.04-1.12) and (OR = 1.10, 95% CI 1.06-1.14), respectively. Similar associations were seen for 1-day lag and 3-day average lag ozone levels. PM2.5 was not associated with the outcome in either study design. Dose-response assessment indicated a statistically significant and increasing association around 50-55 ppb consistent for both study designs. Ozone was statistically positively associated with pediatric asthma ED visits in Newark, NJ. Our results were generally comparable across the time-series and case-crossover study designs, indicating both are useful to assess local air pollution impacts.

Interaction Effects of Temperature and Ozone on Lung Function and Markers of Systemic Inflammation, Coagulation, and Fibrinolysis: A Crossover Study of Healthy Young Volunteers

PubMed Central

Kahle, Juliette J.; Neas, Lucas M.; Devlin, Robert B.; Case, Martin W.; Schmitt, Michael T.; Madden, Michael C.

2014-01-01

Background: Trends in climate suggest that extreme weather events such as heat waves will become more common. High levels of the gaseous pollutant ozone are associated with elevated temperatures. Ozone has been associated with respiratory diseases as well as cardiovascular morbidity and mortality and can reduce lung function and alter systemic markers of fibrinolysis. The interaction between ozone and temperature is unclear. Methods: Sixteen healthy volunteers were exposed in a randomized crossover study to 0.3 ppm ozone and clean air for 2 hr at moderate (22°C) temperature and again at an elevated temperature (32.5°C). In each case lung function was performed and blood taken before and immediately after exposure and the next morning. Results: Ozone exposure at 22°C resulted in a decrease in markers of fibrinolysis the next day. There was a 51.8% net decrease in PAI-1 (plasminogen activator inhibitor-1), a 12.1% net decrease in plasminogen, and a 17.8% net increase in D-dimer. These significantly differed from the response at 32.5°C, where there was a 44.9% (p = 0.002) and a 27.9% (p = 0.001) increase in PAI-1 and plasminogen, respectively, and a 12.5% (p = 0.042) decrease in D-dimer. In contrast, decrements in lung function following ozone exposure were comparable at both moderate and elevated temperatures (forced expiratory volume in 1 sec, –12.4% vs. –7.5%, p > 0.05). No changes in systemic markers of inflammation were observed for either temperature. Conclusion: Ozone-induced systemic but not respiratory effects varied according to temperature. Our study suggests that at moderate temperature ozone may activate the fibrinolytic pathway, while at elevated temperature ozone may impair it. These findings provide a biological basis for the interaction between temperature and ozone on mortality observed in some epidemiologic studies. Citation: Kahle JJ, Neas LM, Devlin RB, Case MW, Schmitt MT, Madden MC, Diaz-Sanchez D. 2015. Interaction effects of temperature and ozone on lung function and markers of systemic inflammation, coagulation, and fibrinolysis: a crossover study of healthy young volunteers. Environ Health Perspect 123:310–316; http://dx.doi.org/10.1289/ehp.1307986 PMID:25514459

A Time-Stratified Case-Crossover Study of Ambient Ozone Exposure and Emergency Department Visits for Specific Respiratory Diagnoses in California (2005–2008)

PubMed Central

Malig, Brian J.; Pearson, Dharshani L.; Chang, Yun Brenda; Broadwin, Rachel; Basu, Rupa; Green, Rochelle S.; Ostro, Bart

2015-01-01

Background: Studies have explored ozone’s connection to asthma and total respiratory emergency department visits (EDVs) but have neglected other specific respiratory diagnoses despite hypotheses relating ozone to respiratory infections and allergic responses. Objective: We examined relationships between ozone and EDVs for respiratory visits, including specifically acute respiratory infections (ARI), asthma, pneumonia, chronic obstructive pulmonary disease (COPD), and upper respiratory tract inflammation (URTI). Methods: We conducted a multi-site time-stratified case-crossover study of ozone exposures for approximately 3.7 million respiratory EDVs from 2005 through 2008 among California residents living within 20 km of an ozone monitor. Conditional logistic regression was used to estimate associations by climate zone. Random effects meta-analysis was then applied to estimate pooled excess risks (ER). Effect modification by season, distance from the monitor and individual demographic characteristics (i.e., age, race/ethnicity, sex, and payment method), and confounding by other gaseous air pollutants were also investigated. Meta-regression was utilized to explore how climate zone–level meteorological, demographic, and regional differences influenced estimates. Results: We observed ozone-associated increases in all respiratory, asthma, and ARI visits, which were slightly larger in the warm season [asthma ER per 10-ppb increase in mean of same and previous 3 days ozone exposure (lag03) = 2.7%, 95% CI: 1.5, 3.9; ARI ERlag03 = 1.4%, 95% CI: 0.8, 1.9]. EDVs for pneumonia, COPD, and URTI were also significantly associated with ozone exposure over the whole year, but typically more consistently so during the warm season. Conclusions: Short-term ozone exposures among California residents living near an ozone monitor were positively associated with EDVs for asthma, ARI, pneumonia, COPD, and URTI from 2005 through 2008. Those associations were typically larger and more consistent during the warm season. Our findings suggest that these outcomes should be considered when evaluating the potential health benefits of reducing ozone concentrations. Citation: Malig BJ, Pearson DL, Chang YB, Broadwin R, Basu R, Green RS, Ostro B. 2016. A time-stratified case-crossover study of ambient ozone exposure and emergency department visits for specific respiratory diagnoses in California (2005–2008). Environ Health Perspect 124:745–753; http://dx.doi.org/10.1289/ehp.1409495 PMID:26647366

Nimbus-7 Total Ozone Mapping Spectrometer (TOMS) Data Products User's Guide

NASA Technical Reports Server (NTRS)

McPeters, Richard D.; Bhartia, P. K.; Krueger, Arlin J.; Herman, Jay R.; Schlesinger, Barry M.; Wellemeyer, Charles G.; Seftor, Colin J.; Jaross, Glen; Taylor, Steven L.; Swissler, Tom;