Science.gov

Sample records for 8-h averaged ozone

  1. Average ozone vertical distribution at Sodankyla based on the 1988-1991 ozone sounding data

    NASA Technical Reports Server (NTRS)

    Kyro, Esko; Rummukainen, Markku; Taalas, Petteri; Supperi, Ari

    1994-01-01

    The study presents the statistical analysis of ozone sonde data obtained at Sodankyla (67.4 deg N, 26.6 deg E) from the beginning of the sounding program on March 1988 to the end of December 1991. The Sodankyla sounding data offers the longest continuous record of the ozone vertical distribution in the European Arctic. In this paper, we present the average ozone partial pressures within each 1 km column obtained for different seasons during the almost four year long period. We believe that the data represented here are useful as an interim reference ozone atmosphere, especially considering the fact that northern Scandinavia has become a popular campaign site for the big international ozone experiments.

  2. Radial diffusive samplers for determination of 8-h concentration of BTEX, acetone, ethanol and ozone in ambient air during a sea breeze event

    NASA Astrophysics Data System (ADS)

    Roukos, Joelle; Locoge, Nadine; Sacco, Paolo; Plaisance, Hervé

    2011-01-01

    The radial diffusive sampler Radiello ® filled with Carbograph 4 was evaluated for monitoring BTEX, ethanol and acetone concentrations for 8-hour exposure time. The sampling rates were first evaluated in an exposure chamber under standard conditions. Benzene and toluene showed the highest sampling rates with satisfactory standard deviations. Ethylbenzene and xylenes showed medium sampling rates but higher standard deviations that can be attributed to a low affinity of these compounds with the adsorbent medium for short sampling time. Acetone has a fair result because of the increase of its partial pressure in the vicinity of the adsorbent surface in the course of sampling. The Carbograph 4 adsorbent does not seem to be suitable for sampling ethanol, likely because of its high volatility. The influences of three environmental factors (temperature (T), relative humidity (RH) and concentration level (C)) on the sampling rates were also evaluated, following a fractional factorial design at two factor levels (low and high). Results were only investigated on benzene, toluene and acetone. Temperature and relative humidity are found to be the most important factors leading to variability of the benzene and toluene sampling rates. The applicability of the sampler for 8-hour sampling was demonstrated by the results of a measurement campaign carried out during a sea breeze event. Mapping of benzene, toluene and acetone concentrations showed the highest concentrations in the industrial zone following the wind direction coming from the North. Nevertheless, the sea breeze tends to reduce the spread of the industrial plumes. On the contrary, the ozone map presents the lowest concentrations at the same industrial area indicating a net consumption of ozone. The highest ozone concentrations were found in the southeastern zone suggesting a local ozone formation.

  3. A Kalman-filter bias correction of ozone deterministic, ensemble-averaged, and probabilistic forecasts

    SciTech Connect

    Monache, L D; Grell, G A; McKeen, S; Wilczak, J; Pagowski, M O; Peckham, S; Stull, R; McHenry, J; McQueen, J

    2006-03-20

    Kalman filtering (KF) is used to postprocess numerical-model output to estimate systematic errors in surface ozone forecasts. It is implemented with a recursive algorithm that updates its estimate of future ozone-concentration bias by using past forecasts and observations. KF performance is tested for three types of ozone forecasts: deterministic, ensemble-averaged, and probabilistic forecasts. Eight photochemical models were run for 56 days during summer 2004 over northeastern USA and southern Canada as part of the International Consortium for Atmospheric Research on Transport and Transformation New England Air Quality (AQ) Study. The raw and KF-corrected predictions are compared with ozone measurements from the Aerometric Information Retrieval Now data set, which includes roughly 360 surface stations. The completeness of the data set allowed a thorough sensitivity test of key KF parameters. It is found that the KF improves forecasts of ozone-concentration magnitude and the ability to predict rare events, both for deterministic and ensemble-averaged forecasts. It also improves the ability to predict the daily maximum ozone concentration, and reduces the time lag between the forecast and observed maxima. For this case study, KF considerably improves the predictive skill of probabilistic forecasts of ozone concentration greater than thresholds of 10 to 50 ppbv, but it degrades it for thresholds of 70 to 90 ppbv. Moreover, KF considerably reduces probabilistic forecast bias. The significance of KF postprocessing and ensemble-averaging is that they are both effective for real-time AQ forecasting. KF reduces systematic errors, whereas ensemble-averaging reduces random errors. When combined they produce the best overall forecast.

  4. DEVELOMENT AND EVALUATION OF A MODEL FOR ESTIMATING LONG-TERM AVERAGE OZONE EXPOSURES TO CHILDREN

    EPA Science Inventory

    Long-term average exposures of school-age children can be modelled using longitudinal measurements collected during the Harvard Southern California Chronic Ozone Exposure Study over a 12-month period: June, 1995-May, 1996. The data base contains over 200 young children with perso...

  5. Radiative forcing and climate metrics for ozone precursor emissions: the impact of multi-model averaging

    NASA Astrophysics Data System (ADS)

    MacIntosh, C. R.; Shine, K. P.; Collins, W. J.

    2015-04-01

    Multi-model ensembles are frequently used to assess understanding of the response of ozone and methane lifetime to changes in emissions of ozone precursors such as NOx, VOCs (volatile organic compounds) and CO. When these ozone changes are used to calculate radiative forcing (RF) (and climate metrics such as the global warming potential (GWP) and global temperature-change potential (GTP)) there is a methodological choice, determined partly by the available computing resources, as to whether the mean ozone (and methane) concentration changes are input to the radiation code, or whether each model's ozone and methane changes are used as input, with the average RF computed from the individual model RFs. We use data from the Task Force on Hemispheric Transport of Air Pollution source-receptor global chemical transport model ensemble to assess the impact of this choice for emission changes in four regions (East Asia, Europe, North America and South Asia). We conclude that using the multi-model mean ozone and methane responses is accurate for calculating the mean RF, with differences up to 0.6% for CO, 0.7% for VOCs and 2% for NOx. Differences of up to 60% for NOx 7% for VOCs and 3% for CO are introduced into the 20 year GWP. The differences for the 20 year GTP are smaller than for the GWP for NOx, and similar for the other species. However, estimates of the standard deviation calculated from the ensemble-mean input fields (where the standard deviation at each point on the model grid is added to or subtracted from the mean field) are almost always substantially larger in RF, GWP and GTP metrics than the true standard deviation, and can be larger than the model range for short-lived ozone RF, and for the 20 and 100 year GWP and 100 year GTP. The order of averaging has most impact on the metrics for NOx, as the net values for these quantities is the residual of the sum of terms of opposing signs. For example, the standard deviation for the 20 year GWP is 2-3 times larger

  6. Radiative forcing and climate metrics for ozone precursor emissions: the impact of multi-model averaging

    NASA Astrophysics Data System (ADS)

    MacIntosh, C. R.; Shine, K. P.; Collins, W. J.

    2014-10-01

    Multi-model ensembles are frequently used to assess understanding of the response of ozone and methane lifetime to changes in emissions of ozone precursors such as NOx, VOC and CO. When these ozone changes are used to calculate radiative forcing (RF) (and climate metrics such as the global warming potential (GWP) and global temperature potential (GTP)) there is a methodological choice, determined partly by the available computing resources, as to whether the mean ozone (and methane lifetime) changes are input to the radiation code, or whether each model's ozone and methane changes are used as input, with the average RF computed from the individual model RFs. We use data from the Task Force on Hemispheric Transport of Air Pollution Source-Receptor global chemical transport model ensemble to assess the impact of this choice for emission changes in 4 regions (East Asia, Europe, North America and South Asia). We conclude that using the multi-model mean ozone and methane responses is accurate for calculating the mean RF, with differences up to 0.6% for CO, 0.7% for VOC and 2% for NOx. Differences of up to 60% for NOx 7% for VOC and 3% for CO are introduced into the 20 year GWP as a result of the exponential decay terms, with similar values for the 20 years GTP. However, estimates of the SD calculated from the ensemble-mean input fields (where the SD at each point on the model grid is added to or subtracted from the mean field) are almost always substantially larger in RF, GWP and GTP metrics than the true SD, and can be larger than the model range for short-lived ozone RF, and for the 20 and 100 year GWP and 100 year GTP. We find that the effect is generally most marked for the case of NOx emissions, where the net effect is a smaller residual of terms of opposing signs. For example, the SD for the 20 year GWP is two to three times larger using the ensemble-mean fields than using the individual models to calculate the RF. Hence, while the average of multi-model fields

  7. Exponential approximation for daily average solar heating or photolysis. [of stratospheric ozone layer

    NASA Technical Reports Server (NTRS)

    Cogley, A. C.; Borucki, W. J.

    1976-01-01

    When incorporating formulations of instantaneous solar heating or photolytic rates as functions of altitude and sun angle into long range forecasting models, it may be desirable to replace the time integrals by daily average rates that are simple functions of latitude and season. This replacement is accomplished by approximating the integral over the solar day by a pure exponential. This gives a daily average rate as a multiplication factor times the instantaneous rate evaluated at an appropriate sun angle. The accuracy of the exponential approximation is investigated by a sample calculation using an instantaneous ozone heating formulation available in the literature.

  8. Version 8 SBUV Ozone Profile Trends Compared with Trends from a Zonally Averaged Chemical Model

    NASA Technical Reports Server (NTRS)

    Rosenfield, Joan E.; Frith, Stacey; Stolarski, Richard

    2004-01-01

    Linear regression trends for the years 1979-2003 were computed using the new Version 8 merged Solar Backscatter Ultraviolet (SBUV) data set of ozone profiles. These trends were compared to trends computed using ozone profiles from the Goddard Space Flight Center (GSFC) zonally averaged coupled model. Observed and modeled annual trends between 50 N and 50 S were a maximum in the higher latitudes of the upper stratosphere, with southern hemisphere (SH) trends greater than northern hemisphere (NH) trends. The observed upper stratospheric maximum annual trend is -5.5 +/- 0.9 % per decade (1 sigma) at 47.5 S and -3.8 +/- 0.5 % per decade at 47.5 N, to be compared with the modeled trends of -4.5 +/- 0.3 % per decade in the SH and -4.0 +/- 0.2% per decade in the NH. Both observed and modeled trends are most negative in winter and least negative in summer, although the modeled seasonal difference is less than observed. Model trends are shown to be greatest in winter due to a repartitioning of chlorine species and the increasing abundance of chlorine with time. The model results show that trend differences can occur depending on whether ozone profiles are in mixing ratio or number density coordinates, and on whether they are recorded on pressure or altitude levels.

  9. A New Method of Deriving Time-Averaged Tropospheric Column Ozone over the Tropics Using Total Ozone Mapping Spectrometer (TOMS) Radiances: Intercomparison and Analysis Using TRACE A Data

    NASA Technical Reports Server (NTRS)

    Kim, J. H.; Hudson, R. D.; Thompson, A. M.

    1996-01-01

    Error analysis of archived total 03 from total ozone mapping spectrometer (TOMS) (version 6) presented. Daily total 03 maps for the tropics, from the period October 6-21, 1992, are derived from TOMS radiances following correction for these errors. These daily maps, averaged together, show a wavelike feature, which is observed in all latitude bands, underlying sharp peaks which occur at different longitudes depending on the latitude. The wave pattern is used to derive both time-averaged stratospheric and tropospheric 03 fields. The nature of the wave pattern (stratospheric or tropospheric) cannot be determined with certainty due to missing data (no Pacific sondes, no lower stratospheric Stratospheric Aerosol and Gas Experiment (SAGE) ozone for 18 months after the Mt. Pinatubo eruption) and significant uncertainties in the corroborative satellite record in the lower stratosphere (solar backscattered ultraviolet (SBUV), microwave limb sounder (MLS)). However, the time- averaged tropospheric ozone field, based on the assumption that the wave feature is stratospheric, agrees within 10% with ultraviolet differential absorption laser Transport and Atmospheric Chemistry near the Equator-Atlantic) (TRACE A) 03 measurements from the DC-8 and with ozonesonde measurements over Brazzaville, Congo, Ascension Island, and Natal, Brazil, for the period October 6-21, 1992. The derived background (nonpolluted) Indian Ocean tropospheric ozone amount, 26 Dobson units (DU), agrees with the cleanest African ozonesonde profiles for September-October 1992. The assumption of a totally tropospheric wave (flat stratosphere) gives 38 DU above the western Indian Ocean and 15-40% disagreements with the sondes. Tropospheric column 03 is high from South America to Africa, owing to interaction of dynamics with biomass burning emissions. Comparison with fire distributions from advanced very high resolution radiometer (AVHHR) during October 1992 suggests that tropospheric 03 produced from biomass

  10. Ozone

    MedlinePlus

    ... reactive form of oxygen. In the upper atmosphere, ozone forms a protective layer that shields us from the sun’s ultraviolet rays. At ground level, ozone is a harmful air pollutant and a primary ...

  11. Ozone

    MedlinePlus

    Ozone is a gas. It can be good or bad, depending on where it is. "Good" ozone occurs naturally about 10 to 30 miles above ... the sun's ultraviolet rays. Part of the good ozone layer is gone. Man-made chemicals have destroyed ...

  12. Uses of monoclonal antibody 8H9

    DOEpatents

    Cheung, Nai-Kong V.

    2010-06-22

    This invention provides a composition comprising an effective amount of monoclonal antibody 8H9 or a derivative thereof and a suitable carrier. This invention provides a pharmaceutical composition comprising an effective amount of monoclonal antibody 8H9 or a derivative thereof and a pharmaceutically acceptable carrier. This invention also provides an antibody other than the monoclonal antibody 8H9 comprising the complementary determining regions of monoclonal antibody 8H9 or a derivative thereof, capable of binding to the same antigen as the monoclonal antibody 8H9. This invention provides a substance capable of competitively inhibiting the binding of monoclonal antibody 8H9. This invention also provides an isolated scFv of monoclonal antibody 8H9 or a derivative thereof. This invention also provides the 8H9 antigen. This invention also provides different uses of the monoclonal antibody 8H9 or its derivative.

  13. Uses of monoclonal antibody 8H9

    DOEpatents

    Cheung, Nai-Kong V.

    2013-04-09

    This invention provides a composition comprising an effective amount of monoclonal antibody 8H9 or a derivative thereof and a suitable carrier. This invention provides a pharmaceutical composition comprising an effective amount of monoclonal antibody 8H9 or a derivative thereof and a pharmaceutically acceptable carrier. This invention also provides an antibody other than the monoclonal antibody 8H9 comprising the complementary determining regions of monoclonal antibody 8H9 or a derivative thereof, capable of binding to the same antigen as the monoclonal antibody 8H9. This invention provides a substance capable of competitively inhibiting the binding of monoclonal antibody 8H9. This invention also provides an isolated scFv of monoclonal antibody 8H9 or a derivative thereof. This invention also provides the 8H9 antigen. This invention also provides different uses of the monoclonal antibody 8H9 or its derivative.

  14. Uses of monoclonal antibody 8H9

    DOEpatents

    Cheung, Nai-Kong V.

    2010-06-15

    This invention provides a composition comprising an effective amount of monoclonal antibody 8H9 or a derivative thereof and a suitable carrier. This invention provides a pharmaceutical composition comprising an effective amount of monoclonal antibody 8H9 or a derivative thereof and a pharmaceutically acceptable carrier. This invention also provides an antibody other than the monoclonal antibody 8H9 comprising the complementary determining regions of monoclonal antibody 8H9 or a derivative thereof, capable of binding to the same antigen as the monoclonal antibody 8H9. This invention provides a substance capable of competitively inhibiting the binding of monoclonal antibody 8H9. This invention also provides an isolated scFv of monoclonal antibody 8H9 or a derivative thereof. This invention also provides the 8H9 antigen. This invention also provides a method of inhibiting the growth of tumor cells comprising contacting said tumor cells with an appropriate amount of monoclonal antibody 8H9 or a derivative thereof.

  15. Uses of monoclonal antibody 8H9

    DOEpatents

    Cheung, Nai-Kong V

    2013-08-06

    This invention provides a composition comprising an effective amount of monoclonal antibody 8H9 or a derivative thereof and a suitable carrier. This invention provides a pharmaceutical composition comprising an effective amount of monoclonal antibody 8H9 or a derivative thereof and a pharmaceutically acceptable carrier. This invention also provides an antibody other than the monoclonal antibody 8H9 comprising the complementary determining regions of monoclonal antibody 8H9 or a derivative thereof, capable of binding to the same antigen as the monoclonal antibody 8H9. This invention provides a substance capable of competitively inhibiting the binding of monoclonal antibody 8H9. This invention also provides an isolated scFv of monoclonal antibody 8H9 or a derivative thereof. This invention also provides the 8H9 antigen. This invention also provides a method of inhibiting the growth of tumor cells comprising contacting said tumor cells with an appropriate amount of monoclonal antibody 8H9 or a derivative thereof.

  16. Ozone

    SciTech Connect

    Not Available

    1988-06-01

    The author discusses the debate over whether concern about a hole in the ozone layer in Antarctic is real or science fiction. There is a growing consensus that efforts must be taken to protect the ozone layer. The issue now is not whether chlorofluorocarbons (CFCs) should be controlled and regulated but how much and how soon. The United States has urged that the production of dangerous CFCs, and any other chemicals that affect the ozone layer, be restricted immediately to current levels and that their use be reduced 95 percent over the next decade. The American position was too strong for many European nations and the Japanese. Negotiations at an international conference on the matter broke down. The breakdown is due in part to a more acute concern for environmental matters in the United States than exists in many countries. Meanwhile CFCs are linked to another environmental problem that equally threatens the world - the Greenhouse Effect. The earth is in a natural warming period, but man could be causing it to become even warmer. The Greenhouse Effect could have a catastrophic impact on mankind, although nothing has been proven yet.

  17. Uses of monoclonial antibody 8H9

    DOEpatents

    Cheung, Nai-Kong V.

    2015-06-23

    This invention provides an antibody that binds the same antigen as that of monoclonal antibody 8H9, wherein the heavy chain CDR (Complementary Determining Region)1 comprises NYDIN, heavy chain CDR2 comprises WIFPGDGSTQY, heavy chain CDR3 comprises QTTATWFAY, and the light chain CDR1 comprises RASQSISDYLH, light chain CDR2 comprises YASQSIS, and light chain CDR3 comprises QNGHSFPLT. In another embodiment, there is provided a polypeptide that binds the same antigen as that of monoclonal antibody 8H9, wherein the polypeptide comprises NYDIN, WIFPGDGSTQY, QTTATWFAY, RASQSISDYLH, YASQSIS, and QNGHSFPLT.

  18. The Effect of Lightning NOx Production on Surface Ozone in the Continental United States

    NASA Technical Reports Server (NTRS)

    Kaynak, B.; Hu, Y.; Martin, R. V.; Russell, A. G.; Choi, Y.; Wang, Y.

    2008-01-01

    Lightning NO(x) emissions calculated using the US National Lightning Detection Network data were found to account for 30% of the total NO(x) emissions for July August 2004, a period chosen both for having higher lightning NO(x) production and high ozone levels, thus maximizing the likelihood that such emissions could impact peak ozone levels. Including such emissions led to modest, but sometimes significant increases in simulated surface ozone when using the Community Multi-scale Air Quality Model (CMAQ). Three model simulations were performed, two with the addition of lightning NO(x) emissions, and one without. Domain-wide daily maximum 8-h ozone changes due to lightning NO(x) were less than 2 ppbv in 71 % of the cases with a maximum of 10 ppbv; whereas the difference in 1-h ozone was less than 2 ppbv in 77% of the cases with a maximum of 6 ppbv. Daily maximum 1-h and 8-h ozone for grids containing O3 monitoring stations changed slightly, with more than 43% of the cases differing less than 2 ppbv. The greatest differences were 42 ppbv for both 1-h and 8-h O3 , though these tended to be on days of lower ozone. Lightning impacts on the season-wide maximum 1-h and 8-h averaged ozone decreased starting from the 1 st to 4th highest values (an average of 4th highest, 8-h values is used for attainment demonstration in the US). Background ozone values from the y-intercept of O3 versus NO(z) curve were 42.2 and 43.9 ppbv for simulations without and with lightning emissions, respectively. Results from both simulations with lightning NO(x) suggest that while North American lightning production of NO(x) can lead to significant local impacts on a few occasions, they will have a relatively small impact on typical maximum levels and determination of Policy Relevant Background levels.

  19. 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.

  20. Surface Ozone Background in the United States: Canadian and Mexican Pollution Influences

    EPA Science Inventory

    We use a global chemical transport model (GEOS-Chem) with 1° x 1° horizontal resolution to quantify the effects of anthropogenic emissions from Canada, Mexico, and outside North America on daily maximum 8-h average ozone concentrations in U.S.surface air.

  1. Ozone reaction with interior building materials: Influence of diurnal ozone variation, temperature and humidity

    NASA Astrophysics Data System (ADS)

    Rim, Donghyun; Gall, Elliott T.; Maddalena, Randy L.; Nazaroff, William W.

    2016-01-01

    Elevated tropospheric ozone concentrations are associated with increased morbidity and mortality. Indoor ozone chemistry affects human exposure to ozone and reaction products that also may adversely affect health and comfort. Reactive uptake of ozone has been characterized for many building materials; however, scant information is available on how diurnal variation of ambient ozone influences ozone reaction with indoor surfaces. The primary objective of this study is to investigate ozone-surface reactions in response to a diurnally varying ozone exposure for three common building materials: ceiling tile, painted drywall, and carpet tile. A secondary objective is to examine the effects of air temperature and humidity. A third goal is to explore how conditioning of materials in an occupied office building might influence subsequent ozone-surface reactions. Experiments were performed at bench-scale with inlet ozone concentrations varied to simulate daytime (ozone elevated) and nighttime (ozone-free in these experiments) periods. To simulate office conditions, experiments were conducted at two temperatures (22 °C and 28 °C) and three relative humidity values (25%, 50%, 75%). Effects of indoor surface exposures were examined by placing material samples in an occupied office and repeating bench-scale characterization after exposure periods of 1 and 2 months. Deposition velocities were observed to be highest during the initial hour of ozone exposure with slow decrease in the subsequent hours of simulated daytime conditions. Daily-average ozone reaction probabilities for fresh materials are in the respective ranges of (1.7-2.7) × 10-5, (2.8-4.7) × 10-5, and (3.0-4.5) × 10-5 for ceiling tile, painted drywall, and carpet tile. The reaction probability decreases by 7%-47% across the three test materials after two 8-h periods of ozone exposure. Measurements with the samples from an occupied office reveal that deposition velocity can decrease or increase with time

  2. Which metric of ambient ozone to predict daily mortality?

    NASA Astrophysics Data System (ADS)

    Moshammer, Hanns; Hutter, Hans-Peter; Kundi, Michael

    2013-02-01

    It is well known that ozone concentration is associated with daily cause specific mortality. But which ozone metric is the best predictor of the daily variability in mortality? We performed a time series analysis on daily deaths (all causes, respiratory and cardiovascular causes as well as death in elderly 65+) in Vienna for the years 1991-2009. We controlled for seasonal and long term trend, day of the week, temperature and humidity using the same basic model for all pollutant metrics. We found model fit was best for same day variability of ozone concentration (calculated as the difference between daily hourly maximum and minimum) and hourly maximum. Of these the variability displayed a more linear dose-response function. Maximum 8 h moving average and daily mean value performed not so well. Nitrogen dioxide (daily mean) in comparison performed better when previous day values were assessed. Same day ozone and previous day nitrogen dioxide effect estimates did not confound each other. Variability in daily ozone levels or peak ozone levels seem to be a better proxy of a complex reactive secondary pollutant mixture than daily average ozone levels in the Middle European setting. If this finding is confirmed this would have implications for the setting of legally binding limit values.

  3. The influence of meteorological factors and biomass burning on surface ozone concentrations at Tanah Rata, Malaysia

    NASA Astrophysics Data System (ADS)

    Toh, Ying Ying; Lim, Sze Fook; von Glasow, Roland

    2013-05-01

    The surface ozone concentrations at the Tanah Rata regional Global Atmosphere Watch (GAW) station, Malaysia (4°28‧N, 101°23‧E, 1545 m above Mean Sea Level (MSL)) from June 2006 to August 2008 were analyzed in this study. Overall the ozone mixing ratios are very low; the seasonal variations show the highest mixing ratios during the Southwest monsoon (average 19.1 ppb) and lowest mixing ratios during the spring intermonsoon (average 14.2 ppb). The diurnal variation of ozone is characterised by an afternoon maximum and night time minimum. The meteorological conditions that favour the formation of high ozone levels at this site are low relative humidity, high temperature and minimum rainfall. The average ozone concentration is lower during precipitation days compared to non-precipitation days. The hourly averaged ozone concentrations show significant correlations with temperature and relative humidity during the Northeast monsoon and spring intermonsoon. The highest concentrations are observed when the wind is blowing from the west. We found an anticorrelation between the atmospheric pressure tide and ozone concentrations. The ozone mixing ratios do not exceed the recommended Malaysia Air Quality Guidelines for 1-h and 8-h averages. Five day backward trajectories on two high ozone episodes in 07 August 2006 (40.0 ppb) and 24 February 2008 (45.7 ppb) are computed using the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to investigate the origin of the pollutants and influence of regional transport. The high ozone episode during 07 August 2006 (burning season during southwest monsoon) is mainly attributed to regional transport from biomass burning in Sumatra, whereas favourable meteorological conditions (i.e. low relative humidity, high temperature and solar radiation, zero rainfall) and long range transport from Indo-China have elevated the ozone concentrations during 24 February 2008.

  4. Contributors to ozone episodes in three US/Mexico border twin-cities.

    PubMed

    Shi, Chune; Fernando, H J S; Yang, Jie

    2009-09-01

    The Process Analysis tools of the Community Multiscale Air Quality (CMAQ) modeling system together with back-trajectory analysis were used to assess potential contributors to ozone episodes that occurred during June 1-4, 2006, in three populated U.S.-Mexico border twin cities: San Diego/Tijuana, Imperial/Mexicali and El Paso/Ciudad Juárez. Validation of CMAQ output against surface ozone measurements indicates that the predictions are acceptable with regard to commonly recommended statistical standards and comparable to other reported studies. The mean normalized bias test (MNBT) and mean normalized gross error (MNGE) for hourly ozone fall well within the US EPA suggested range of +/-15% and 35%, respectively, except MNBT for El Paso. The MNBTs for maximum 8-h average ozone are larger than those for hourly ozone, but all the simulated maximum 8-h average ozone are within a factor of 2 of those measured in all three regions. The process and back-trajectory analyses indicate that the main sources of daytime ground-level ozone are the local photochemical production and regional transport. By integrating the effects of each process over the depth of the daytime planetary boundary layer (PBL), it is found that in the San Diego area (SD), chemistry and vertical advection contributed about 36%/48% and 64%/52% for June 2 and 3, respectively. This confirms the previous finding that high-altitude regional transport followed by fumigation contributes significantly to ozone in SD. The back-trajectory analysis shows that this ozone was mostly transported from the coastal area of southern California. For the episodes in Imperial Valley and El Paso, respectively, ozone was transported from the coastal areas of southern California and Mexico and from northern Texas and Oklahoma.

  5. Contributors to ozone episodes in three US/Mexico border twin-cities.

    PubMed

    Shi, Chune; Fernando, H J S; Yang, Jie

    2009-09-01

    The Process Analysis tools of the Community Multiscale Air Quality (CMAQ) modeling system together with back-trajectory analysis were used to assess potential contributors to ozone episodes that occurred during June 1-4, 2006, in three populated U.S.-Mexico border twin cities: San Diego/Tijuana, Imperial/Mexicali and El Paso/Ciudad Juárez. Validation of CMAQ output against surface ozone measurements indicates that the predictions are acceptable with regard to commonly recommended statistical standards and comparable to other reported studies. The mean normalized bias test (MNBT) and mean normalized gross error (MNGE) for hourly ozone fall well within the US EPA suggested range of +/-15% and 35%, respectively, except MNBT for El Paso. The MNBTs for maximum 8-h average ozone are larger than those for hourly ozone, but all the simulated maximum 8-h average ozone are within a factor of 2 of those measured in all three regions. The process and back-trajectory analyses indicate that the main sources of daytime ground-level ozone are the local photochemical production and regional transport. By integrating the effects of each process over the depth of the daytime planetary boundary layer (PBL), it is found that in the San Diego area (SD), chemistry and vertical advection contributed about 36%/48% and 64%/52% for June 2 and 3, respectively. This confirms the previous finding that high-altitude regional transport followed by fumigation contributes significantly to ozone in SD. The back-trajectory analysis shows that this ozone was mostly transported from the coastal area of southern California. For the episodes in Imperial Valley and El Paso, respectively, ozone was transported from the coastal areas of southern California and Mexico and from northern Texas and Oklahoma. PMID:19559465

  6. Synoptic and meteorological drivers of extreme ozone concentrations over Europe

    NASA Astrophysics Data System (ADS)

    Otero, N.; Sillmann, J.; Schnell, J. L.; Rust, H. W.; Butler, T.

    2016-02-01

    The present work assesses the relationship between local and synoptic meteorological conditions and surface ozone concentration over Europe in spring and summer months, during the period 1998-2012 using a new interpolated data set of observed surface ozone concentrations over the European domain. Along with local meteorological conditions, the influence of large-scale atmospheric circulation on surface ozone is addressed through a set of airflow indices computed with a novel implementation of a grid-by-grid weather type classification across Europe. Drivers of surface ozone over the full distribution of maximum daily 8 h average values are investigated, along with drivers of the extreme high percentiles and exceedances or air quality guideline thresholds. Three different regression techniques are applied: multiple linear regression to assess the drivers of maximum daily ozone, logistic regression to assess the probability of threshold exceedances and quantile regression to estimate the meteorological influence on extreme values, as represented by the 95th percentile. The relative importance of the input parameters (predictors) is assessed by a backward stepwise regression procedure that allows the identification of the most important predictors in each model. Spatial patterns of model performance exhibit distinct variations between regions. The inclusion of the ozone persistence is particularly relevant over southern Europe. In general, the best model performance is found over central Europe, where the maximum temperature plays an important role as a driver of maximum daily ozone as well as its extreme values, especially during warmer months.

  7. Assessing the effects of ambient ozone in China on snap bean genotypes by using ethylenediurea (EDU).

    PubMed

    Yuan, Xiangyang; Calatayud, Vicent; Jiang, Lijun; Manning, William J; Hayes, Felicity; Tian, Yuan; Feng, Zhaozhong

    2015-10-01

    Four genotypes of snap bean (Phaseolus vulgaris L.) were selected to study the effects of ambient ozone concentration at a cropland area around Beijing by using 450 ppm of ethylenediurea (EDU) as a chemical protectant. During the growing season, the 8h (9:00-17:00) average ozone concentration was very high, approximately 71.3 ppb, and AOT40 was 29.0 ppm.h. All genotypes showed foliar injury, but ozone-sensitive genotypes exhibited much more injury than ozone-tolerant ones. Compared with control, EDU significantly alleviated foliar injury, increased photosynthesis rate and chlorophyll a fluorescence, Vcmax and Jmax, and seed and pod weights in ozone-sensitive genotypes but not in ozone-tolerant genotypes. EDU did not significantly affect antioxidant contents in any of the genotypes. Therefore, EDU effectively protected sensitive genotypes from ambient ozone damage, while protection on ozone-tolerant genotypes was limited. EDU can be regarded as a useful tool in risk assessment of ambient ozone on food security.

  8. Magnitude, decadal changes, and impact of regional background ozone transported into the greater Houston, Texas, area.

    PubMed

    Berlin, Shaena R; Langford, Andrew O; Estes, Mark; Dong, Melody; Parrish, David D

    2013-12-17

    Two independent analyses of the daily maximum 8 h average ozone concentrations measured during the high ozone season (May through October) at Continuous Ambient Monitoring Stations are used to quantify the regional background ozone transported into the Houston-Galveston-Brazoria (HGB) area. The dependence on wind direction is examined, and long-term trends are determined using measurements made between 1998 and 2012. Both analyses show that the regional background ozone has declined during periods of continental outflow: i.e., the conditions associated with most high ozone episodes in HGB. The changes in regional background ozone found for northeasterly and southeasterly flow are -0.50 ± 0.54 and -0.79 ± 0.65 (95% confidence limit) ppbv yr(-1), respectively, which correspond to decreases of ∼7-11 ppbv between 1998 and 2012. This finding is consistent with the summertime downward trend of -0.45 ppbv yr(-1) (range of sites: -0.87 to +0.07 ppbv yr(-1)) for ozone in the eastern U.S. between 1990 and 2010 reported by Cooper et al. and shows that changing background concentrations are at least partially responsible for the decreased surface ozone in the HGB area over the past decade. Baseline ozone concentrations in air flowing into Texas from the Gulf of Mexico have not changed significantly over this period.

  9. 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.

  10. Ozone Layer Observations

    NASA Technical Reports Server (NTRS)

    McPeters, Richard; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    The US National Aeronautics and Space Administration (NASA) has been monitoring the ozone layer from space using optical remote sensing techniques since 1970. With concern over catalytic destruction of ozone (mid-1970s) and the development of the Antarctic ozone hole (mid-1980s), long term ozone monitoring has become the primary focus of NASA's series of ozone measuring instruments. A series of TOMS (Total Ozone Mapping Spectrometer) and SBUV (Solar Backscatter Ultraviolet) instruments has produced a nearly continuous record of global ozone from 1979 to the present. These instruments infer ozone by measuring sunlight backscattered from the atmosphere in the ultraviolet through differential absorption. These measurements have documented a 15 Dobson Unit drop in global average ozone since 1980, and the declines in ozone in the antarctic each October have been far more dramatic. Instruments that measure the ozone vertical distribution, the SBUV and SAGE (Stratospheric Aerosol and Gas Experiment) instruments for example, show that the largest changes are occurring in the lower stratosphere and upper troposphere. The goal of ozone measurement in the next decades will be to document the predicted recovery of the ozone layer as CFC (chlorofluorocarbon) levels decline. This will require a continuation of global measurements of total column ozone on a global basis, but using data from successor instruments to TOMS. Hyperspectral instruments capable of measuring in the UV will be needed for this purpose. Establishing the relative roles of chemistry and dynamics will require instruments to measure ozone in the troposphere and in the stratosphere with good vertical resolution. Instruments that can measure other chemicals important to ozone formation and destruction will also be needed.

  11. Significant increase of surface ozone at a rural site, north of eastern China

    NASA Astrophysics Data System (ADS)

    Ma, Zhiqiang; Xu, Jing; Quan, Weijun; Zhang, Ziyin; Lin, Weili; Xu, Xiaobin

    2016-03-01

    Ozone pollution in eastern China has become one of the top environmental issues. Quantifying the temporal trend of surface ozone helps to assess the impacts of the anthropogenic precursor reductions and the likely effects of emission control strategies implemented. In this paper, ozone data collected at the Shangdianzi (SDZ) regional atmospheric background station from 2003 to 2015 are presented and analyzed to obtain the variation in the trend of surface ozone in the most polluted region of China, north of eastern China or the North China Plain. A modified Kolmogorov-Zurbenko (KZ) filter method was performed on the maximum daily average 8 h (MDA8) concentrations of ozone to separate the contributions of different factors from the variation of surface ozone and remove the influence of meteorological fluctuations on surface ozone. Results reveal that the short-term, seasonal and long-term components of ozone account for 36.4, 57.6 and 2.2 % of the total variance, respectively. The long-term trend indicates that the MDA8 has undergone a significant increase in the period of 2003-2015, with an average rate of 1.13 ± 0.01 ppb year-1 (R2 = 0.92). It is found that meteorological factors did not significantly influence the long-term variation of ozone and the increase may be completely attributed to changes in emissions. Furthermore, there is no significant correlation between the long-term O3 and NO2 trends. This study suggests that emission changes in VOCs might have played a more important role in the observed increase of surface ozone at SDZ.

  12. Long-term ambient ozone concentration and the incidence of asthma in nonsmoking adults: The Ahsmog study

    SciTech Connect

    McDonnell, W.F.; Abbey, D.E.; Nishino, N.; Lebowitz, M.D.

    1999-02-01

    The authors conducted a prospective study of a cohort of 3091 nonsmokers, ages 27 to 87 years, to evaluate the association between long-term ambient ozone exposure and development of adult-onset asthma. Over a 15-year period, 3.2% of males and 4.3% of females reported new doctor diagnoses of asthma. For males, they observed a significant relationship between report of doctor diagnosis of asthma and 20-year mean 8-h average ambient ozone concentration. The authors observed no such relationship for females. Other variables significantly related to development of asthma were a history of ever-smoking for males, and for females, number of years worked with a smoker, age, and a history of childhood pneumonia or bronchitis. Addition of other pollutants to the models did not diminish the relationship between ozone and asthma for males. These data suggest that long-term exposure to ambient ozone is associated with development of asthma in adult males.

  13. Asteltoxins from the Entomopathogenic Fungus Pochonia bulbillosa 8-H-28.

    PubMed

    Adachi, Hayamitsu; Doi, Hiroyasu; Kasahara, Yuichi; Sawa, Ryuichi; Nakajima, Kaori; Kubota, Yumiko; Hosokawa, Nobuo; Tateishi, Ken; Nomoto, Akio

    2015-07-24

    New asteltoxins C (3) and D (4) were found in the extract of the entomopathogenic fungus Pochonia bulbillosa 8-H-28. Compound 2, which was spectroscopically identical with the known asteltoxin B, was isolated, and structural analysis led to a revision of the structure of asteltoxin B. Compounds 2 and 4 have a novel tricyclic ring system connected to a dienyl α-pyrone structure. Compound 3 has a 2,8-dioxabicyclo[3.3.0]octane ring similar to that of asteltoxin (1). Compound 3 showed potent antiproliferative activity against NIAS-SL64 cells derived from the fat body of Spodoptera litura larvae, while 2 and 4 were inactive.

  14. A 15-year climatology of wind pattern impacts on surface ozone in Houston, Texas

    NASA Astrophysics Data System (ADS)

    Souri, Amir Hossein; Choi, Yunsoo; Li, Xiangshang; Kotsakis, Alexander; Jiang, Xun

    2016-06-01

    Houston is recognized for its large petrochemical industrial facilities providing abundant radicals for tropospheric ozone formation. Fortunately, maximum daily 8-h average (MDA8) surface ozone concentrations have declined in Houston (- 0.6 ± 0.3 ppbv yr- 1) during the summers (i.e., May to September) of 2000 to 2014, possibly due to the reductions in precursor emissions by effective control policies. However, it is also possible that changes in meteorological variables have affected ozone concentrations. This study focused on the impact of long-term wind patterns which have the highest impact on ozone in Houston. The analysis of long-term wind patterns can benefit surface ozone studies by 1) providing wind patterns that distinctly changed ozone levels, 2) investigating the frequency of patterns and the respective changes and 3) estimating ozone trends in specific wind patterns that local emissions are mostly involved, thus separating emissions impacts from meteorology to some extent. To this end, the 900-hPa flow patterns in summers of 2000 to 2014 were clustered in seven classes (C1-C7) by deploying an unsupervised partitioning method. We confirm the characteristics of the clusters from a backward trajectory analysis, monitoring networks, and a regional chemical transport model simulation. The results indicate that Houston has experienced a statistically significant downward trend (- 0.6 ± 0.4 day yr- 1) of the cluster of weak easterly and northeasterly days (C4), when the highest fraction of ozone exceedances (MDA8 > 70 ppbv) occurred. This suggests that the reduction in ozone precursors was not the sole reason for the decrease in ozone exceedance days (- 1.5 ± 0.6 day yr- 1). Further, to examine the efficiency of control policies intended to reduce the amount of ozone, we estimated the trend of MDA8 ozone in C4 and C5 (weak winds) days when local emissions are primarily responsible for high ambient ozone levels. Both C4 and C5 show a large reduction in the

  15. Gridded global surface ozone metrics for atmospheric chemistry model evaluation

    NASA Astrophysics Data System (ADS)

    Sofen, E. D.; Bowdalo, D.; Evans, M. J.; Apadula, F.; Bonasoni, P.; Cupeiro, M.; Ellul, R.; Galbally, I. E.; Girgzdiene, R.; Luppo, S.; Mimouni, M.; Nahas, A. C.; Saliba, M.; Tørseth, K.

    2016-02-01

    The concentration of ozone at the Earth's surface is measured at many locations across the globe for the purposes of air quality monitoring and atmospheric chemistry research. We have brought together all publicly available surface ozone observations from online databases from the modern era to build a consistent data set for the evaluation of chemical transport and chemistry-climate (Earth System) models for projects such as the Chemistry-Climate Model Initiative and Aer-Chem-MIP. From a total data set of approximately 6600 sites and 500 million hourly observations from 1971-2015, approximately 2200 sites and 200 million hourly observations pass screening as high-quality sites in regionally representative locations that are appropriate for use in global model evaluation. There is generally good data volume since the start of air quality monitoring networks in 1990 through 2013. Ozone observations are biased heavily toward North America and Europe with sparse coverage over the rest of the globe. This data set is made available for the purposes of model evaluation as a set of gridded metrics intended to describe the distribution of ozone concentrations on monthly and annual timescales. Metrics include the moments of the distribution, percentiles, maximum daily 8-hour average (MDA8), sum of means over 35 ppb (daily maximum 8-h; SOMO35), accumulated ozone exposure above a threshold of 40 ppbv (AOT40), and metrics related to air quality regulatory thresholds. Gridded data sets are stored as netCDF-4 files and are available to download from the British Atmospheric Data Centre (doi: 10.5285/08fbe63d-fa6d-4a7a-b952-5932e3ab0452). We provide recommendations to the ozone measurement community regarding improving metadata reporting to simplify ongoing and future efforts in working with ozone data from disparate networks in a consistent manner.

  16. Tempo-Spatial Variations of Ambient Ozone-Mortality Associations in the USA: Results from the NMMAPS Data.

    PubMed

    Liu, Tao; Zeng, Weilin; Lin, Hualiang; Rutherford, Shannon; Xiao, Jianpeng; Li, Xing; Li, Zhihao; Qian, Zhengmin; Feng, Baixiang; Ma, Wenjun

    2016-01-01

    Although the health effects of ambient ozone have been widely assessed, their tempo-spatial variations remain unclear. We selected 20 communities (ten each from southern and northern USA) based on the US National Morbidity, Mortality, and Air Pollution Study (NMMAPS) dataset. A generalized linear model (GLM) was used to estimate the season-specific association between each 10 ppb (lag0-2 day average) increment in daily 8 h maximum ozone concentration and mortality in every community. The results showed that in the southern communities, a 10 ppb increment in ozone was linked to an increment of mortality of -0.07%, -0.17%, 0.40% and 0.27% in spring, summer, autumn and winter, respectively. For the northern communities, the excess risks (ERs) were 0.74%, 1.21%, 0.52% and -0.65% in the spring, summer, autumn and winter seasons, respectively. City-specific ozone-related mortality effects were positively related with latitude, but negatively related with seasonal average temperature in the spring, summer and autumn seasons. However, a reverse relationship was found in the winter. We concluded that there were different seasonal patterns of ozone effects on mortality between southern and northern US communities. Latitude and seasonal average temperature were identified as modifiers of the ambient ozone-related mortality risks.

  17. Tempo-Spatial Variations of Ambient Ozone-Mortality Associations in the USA: Results from the NMMAPS Data.

    PubMed

    Liu, Tao; Zeng, Weilin; Lin, Hualiang; Rutherford, Shannon; Xiao, Jianpeng; Li, Xing; Li, Zhihao; Qian, Zhengmin; Feng, Baixiang; Ma, Wenjun

    2016-01-01

    Although the health effects of ambient ozone have been widely assessed, their tempo-spatial variations remain unclear. We selected 20 communities (ten each from southern and northern USA) based on the US National Morbidity, Mortality, and Air Pollution Study (NMMAPS) dataset. A generalized linear model (GLM) was used to estimate the season-specific association between each 10 ppb (lag0-2 day average) increment in daily 8 h maximum ozone concentration and mortality in every community. The results showed that in the southern communities, a 10 ppb increment in ozone was linked to an increment of mortality of -0.07%, -0.17%, 0.40% and 0.27% in spring, summer, autumn and winter, respectively. For the northern communities, the excess risks (ERs) were 0.74%, 1.21%, 0.52% and -0.65% in the spring, summer, autumn and winter seasons, respectively. City-specific ozone-related mortality effects were positively related with latitude, but negatively related with seasonal average temperature in the spring, summer and autumn seasons. However, a reverse relationship was found in the winter. We concluded that there were different seasonal patterns of ozone effects on mortality between southern and northern US communities. Latitude and seasonal average temperature were identified as modifiers of the ambient ozone-related mortality risks. PMID:27571094

  18. Tempo-Spatial Variations of Ambient Ozone-Mortality Associations in the USA: Results from the NMMAPS Data

    PubMed Central

    Liu, Tao; Zeng, Weilin; Lin, Hualiang; Rutherford, Shannon; Xiao, Jianpeng; Li, Xing; Li, Zhihao; Qian, Zhengmin; Feng, Baixiang; Ma, Wenjun

    2016-01-01

    Although the health effects of ambient ozone have been widely assessed, their tempo-spatial variations remain unclear. We selected 20 communities (ten each from southern and northern USA) based on the US National Morbidity, Mortality, and Air Pollution Study (NMMAPS) dataset. A generalized linear model (GLM) was used to estimate the season-specific association between each 10 ppb (lag0-2 day average) increment in daily 8 h maximum ozone concentration and mortality in every community. The results showed that in the southern communities, a 10 ppb increment in ozone was linked to an increment of mortality of −0.07%, −0.17%, 0.40% and 0.27% in spring, summer, autumn and winter, respectively. For the northern communities, the excess risks (ERs) were 0.74%, 1.21%, 0.52% and −0.65% in the spring, summer, autumn and winter seasons, respectively. City-specific ozone-related mortality effects were positively related with latitude, but negatively related with seasonal average temperature in the spring, summer and autumn seasons. However, a reverse relationship was found in the winter. We concluded that there were different seasonal patterns of ozone effects on mortality between southern and northern US communities. Latitude and seasonal average temperature were identified as modifiers of the ambient ozone-related mortality risks. PMID:27571094

  19. Seasonal variation in the acute effects of ozone on premature mortality among elderly Japanese.

    PubMed

    Ng, Chris Fook Sheng; Ueda, Kayo; Nitta, Hiroshi; Takeuchi, Ayano

    2013-10-01

    We conducted a multicity time-series study using monitoring data to assess seasonal patterns of short-term ozone-mortality association among elderly aged 65 years and over in Japan. Daily exposure to ambient ozone was computed using hourly measurements of photochemical oxidants available at multiple monitoring stations in each city. Effects of ozone on daily all-cause non-accidental, cardiovascular, and respiratory mortality were estimated using distributed lag linear models, controlling for confounding by temporal, day of the week, temperature, and flu epidemics. City-level effect estimates were combined using inverse variance meta-analysis. In spring and autumn, a 10-ppbv increase of daily maximum 8-h average ozone concentration in the previous 3 days was associated with 0.69 % (95 % confidence interval (CI): 0.27-1.10), 1.07 % (0.34-1.82), and 1.77 % (0.78-2.77) increases in daily all-cause, cardiovascular, and respiratory mortality, respectively. Forward displacement of respiratory mortality was large during the cold season despite lower ozone concentration. Results were generally independent of fine particulate matter and nitrogen dioxide. Findings suggest significant mortality effects of short-term ozone exposure among the elderly during the moderate season. Those with underlying respiratory diseases were susceptible, even during winter.

  20. Human mortality effects of future concentrations of tropospheric ozone

    NASA Astrophysics Data System (ADS)

    West, J. Jason; Szopa, Sophie; Hauglustaine, Didier A.

    2007-10-01

    Here we explore the effects of projected future changes in global ozone concentrations on premature human mortality, under three scenarios for 2030. We use daily surface ozone concentrations from a global atmospheric transport and chemistry model, and ozone-mortality relationships from daily time-series studies. The population-weighted annual average 8-h daily maximum ozone is projected to increase, relative to the present, in each of ten world regions under the SRES A2 scenario and the current legislation (CLE) scenario, with the largest growth in tropical regions, while decreases are projected in each region in the maximum feasible reduction (MFR) scenario. Emission reductions in the CLE scenario, relative to A2, are estimated to reduce about 190,000 premature human mortalities globally in 2030, with the most avoided mortalities in Africa. The MFR scenario will avoid about 460,000 premature mortalities relative to A2 in 2030, and 270,000 relative to CLE, with the greatest reductions in South Asia.

  1. 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.

  2. Application of dynamic linear regression to improve the skill of ensemble-based deterministic ozone forecasts

    SciTech Connect

    Pagowski, M O; Grell, G A; Devenyi, D; Peckham, S E; McKeen, S A; Gong, W; Monache, L D; McHenry, J N; McQueen, J; Lee, P

    2006-02-02

    Forecasts from seven air quality models and surface ozone data collected over the eastern USA and southern Canada during July and August 2004 provide a unique opportunity to assess benefits of ensemble-based ozone forecasting and devise methods to improve ozone forecasts. In this investigation, past forecasts from the ensemble of models and hourly surface ozone measurements at over 350 sites are used to issue deterministic 24-h forecasts using a method based on dynamic linear regression. Forecasts of hourly ozone concentrations as well as maximum daily 8-h and 1-h averaged concentrations are considered. It is shown that the forecasts issued with the application of this method have reduced bias and root mean square error and better overall performance scores than any of the ensemble members and the ensemble average. Performance of the method is similar to another method based on linear regression described previously by Pagowski et al., but unlike the latter, the current method does not require measurements from multiple monitors since it operates on individual time series. Improvement in the forecasts can be easily implemented and requires minimal computational cost.

  3. Bayesian Maximum Entropy Integration of Ozone Observations and Model Predictions: A National Application.

    PubMed

    Xu, Yadong; Serre, Marc L; Reyes, Jeanette; Vizuete, William

    2016-04-19

    To improve ozone exposure estimates for ambient concentrations at a national scale, we introduce our novel Regionalized Air Quality Model Performance (RAMP) approach to integrate chemical transport model (CTM) predictions with the available ozone observations using the Bayesian Maximum Entropy (BME) framework. The framework models the nonlinear and nonhomoscedastic relation between air pollution observations and CTM predictions and for the first time accounts for variability in CTM model performance. A validation analysis using only noncollocated data outside of a validation radius rv was performed and the R(2) between observations and re-estimated values for two daily metrics, the daily maximum 8-h average (DM8A) and the daily 24-h average (D24A) ozone concentrations, were obtained with the OBS scenario using ozone observations only in contrast with the RAMP and a Constant Air Quality Model Performance (CAMP) scenarios. We show that, by accounting for the spatial and temporal variability in model performance, our novel RAMP approach is able to extract more information in terms of R(2) increase percentage, with over 12 times for the DM8A and over 3.5 times for the D24A ozone concentrations, from CTM predictions than the CAMP approach assuming that model performance does not change across space and time.

  4. Bayesian Maximum Entropy Integration of Ozone Observations and Model Predictions: A National Application.

    PubMed

    Xu, Yadong; Serre, Marc L; Reyes, Jeanette; Vizuete, William

    2016-04-19

    To improve ozone exposure estimates for ambient concentrations at a national scale, we introduce our novel Regionalized Air Quality Model Performance (RAMP) approach to integrate chemical transport model (CTM) predictions with the available ozone observations using the Bayesian Maximum Entropy (BME) framework. The framework models the nonlinear and nonhomoscedastic relation between air pollution observations and CTM predictions and for the first time accounts for variability in CTM model performance. A validation analysis using only noncollocated data outside of a validation radius rv was performed and the R(2) between observations and re-estimated values for two daily metrics, the daily maximum 8-h average (DM8A) and the daily 24-h average (D24A) ozone concentrations, were obtained with the OBS scenario using ozone observations only in contrast with the RAMP and a Constant Air Quality Model Performance (CAMP) scenarios. We show that, by accounting for the spatial and temporal variability in model performance, our novel RAMP approach is able to extract more information in terms of R(2) increase percentage, with over 12 times for the DM8A and over 3.5 times for the D24A ozone concentrations, from CTM predictions than the CAMP approach assuming that model performance does not change across space and time. PMID:26998937

  5. 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.

  6. 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.

  7. Recovery of the Ozone Layer: The Ozone Depleting Gas Index

    NASA Astrophysics Data System (ADS)

    Hofmann, David J.; Montzka, Stephen A.

    2009-01-01

    The stratospheric ozone layer, through absorption of solar ultraviolet radiation, protects all biological systems on Earth. In response to concerns over the depletion of the global ozone layer, the U.S. Clean Air Act as amended in 1990 mandates that NASA and NOAA monitor stratospheric ozone and ozone-depleting substances. This information is critical for assessing whether the Montreal Protocol on Substances That Deplete the Ozone Layer, an international treaty that entered into force in 1989 to protect the ozone layer, is having its intended effect of mitigating increases in harmful ultraviolet radiation. To provide the information necessary to satisfy this congressional mandate, both NASA and NOAA have instituted and maintained global monitoring programs to keep track of ozone-depleting gases as well as ozone itself. While data collected for the past 30 years have been used extensively in international assessments of ozone layer depletion science, the language of scientists often eludes the average citizen who has a considerable interest in the health of Earth's protective ultraviolet radiation shield. Are the ozone-destroying chemicals declining in the atmosphere? When will these chemicals decline to pre-ozone hole levels so that the Antarctic ozone hole might disappear? Will this timing be different in the stratosphere above midlatitudes?

  8. Ozonation of Canadian Athabasca asphaltene

    NASA Astrophysics Data System (ADS)

    Cha, Zhixiong

    Application of ozonation in the petrochemical industry for heavy hydrocarbon upgrading has not been sufficiently explored. Among heavy hydrocarbons, asphaltenes are the heaviest and the most difficult fractions for analysis and treatment. Therefore, ozonation of asphaltenes presents an interesting application in the petrochemical industry. Commercial application of ozonation in the petrochemical industry has three obstacles: availability of an ozone-resistant and environmentally friendly solvent, the precipitation of ozonation intermediates during reaction, and recovery of the solvent and separation of the ozonation products. Preliminary ozonation of Athabasca oil sands asphaltene in nonparticipating solvents encountered serious precipitation of the ozonation intermediates. The precipitated intermediates could be polymeric ozonides and intermolecular ozonides or polymeric peroxides. Because the inhomogeneous reaction medium caused low ozone efficiency, various participating solvents such as methanol and acetic acid were added to form more soluble hydroperoxides. The mass balance results showed that on average, one asphaltene molecule reacted with 12 ozone molecules through the electrophilic reaction and the subsequent decomposition of ozonation intermediates generated acetone extractable products. GC/MS analysis of these compounds indicated that the free radical reactions could be important for generation of volatile products. The extensively ozonated asphaltene in the presence of participating solvents were refluxed with methanol to generate more volatile products. GC/MS analysis of the methanol-esterified ozonation products indicated that most volatile products were aliphatic carboxylic acid esters generated through cleavage of substituents. Reaction kinetics study showed that asphaltene ozonation was initially a diffusion rate-controlled reaction and later developed to a chemical reaction rate-controlled reaction after depletion of the reactive aromatic sites

  9. Unequivocal detection of ozone recovery in the Antarctic Ozone Hole through significant increases in atmospheric layers with minimum ozone

    NASA Astrophysics Data System (ADS)

    de Laat, Jos; van Weele, Michiel; van der A, Ronald

    2015-04-01

    An important new landmark in present day ozone research is presented through MLS satellite observations of significant ozone increases during the ozone hole season that are attributed unequivocally to declining ozone depleting substances. For many decades the Antarctic ozone hole has been the prime example of both the detrimental effects of human activities on our environment as well as how to construct effective and successful environmental policies. Nowadays atmospheric concentrations of ozone depleting substances are on the decline and first signs of recovery of stratospheric ozone and ozone in the Antarctic ozone hole have been observed. The claimed detection of significant recovery, however, is still subject of debate. In this talk we will discuss first current uncertainties in the assessment of ozone recovery in the Antarctic ozone hole by using multi-variate regression methods, and, secondly present an alternative approach to identify ozone hole recovery unequivocally. Even though multi-variate regression methods help to reduce uncertainties in estimates of ozone recovery, great care has to be taken in their application due to the existence of uncertainties and degrees of freedom in the choice of independent variables. We show that taking all uncertainties into account in the regressions the formal recovery of ozone in the Antarctic ozone hole cannot be established yet, though is likely before the end of the decade (before 2020). Rather than focusing on time and area averages of total ozone columns or ozone profiles, we argue that the time evolution of the probability distribution of vertically resolved ozone in the Antarctic ozone hole contains a better fingerprint for the detection of ozone recovery in the Antarctic ozone hole. The advantages of this method over more tradition methods of trend analyses based on spatio-temporal average ozone are discussed. The 10-year record of MLS satellite measurements of ozone in the Antarctic ozone hole shows a

  10. Tropospheric ozone in the vicinity of the ozone hole - 1987 Airborne Antarctic Ozone Experiment

    NASA Technical Reports Server (NTRS)

    Gregory, Gerald L.; Warren, Linda S.; Hypes, Warren D.; Tuck, Adrian F.; Kelly, Kenneth K.; Krueger, Arlin J.

    1989-01-01

    Results are presented on ozone measurements in the upper troposphere/lower stratosphere over Antarctica, obtained by NASA DC-8 aircraft during the August/September 1987 Airborne Antarctic Ozone Experiment. The ozone mixing ratios as high as several hundred ppbv were measured, but in all cases these ratios were observed in pockets of upper atmospheric air, both in the vicinity of and away from the location of the ozone hole. The background ozone values in the surrounding troposphere were typically in the range of 20-50 ppbv. Correlation of tropospheric ozone observations with the boundaries of the ozone hole differed in the course of the experiment. During the August 28 - September 2 flights, encounters with ozone-rich air were limited, and the background tropospheric ozone appeared to decrease beneath the hole. For the later flights, and as the ozone hole deepened, the ozone-rich air was frequently observed in the vicinity of the hole, and the average ozone values at the flight altitude were frequently higher than the background values.

  11. Global health benefits of mitigating ozone pollution with methane emission controls.

    PubMed

    West, J Jason; Fiore, Arlene M; Horowitz, Larry W; Mauzerall, Denise L

    2006-03-14

    Methane (CH(4)) contributes to the growing global background concentration of tropospheric ozone (O(3)), an air pollutant associated with premature mortality. Methane and ozone are also important greenhouse gases. Reducing methane emissions therefore decreases surface ozone everywhere while slowing climate warming, but although methane mitigation has been considered to address climate change, it has not for air quality. Here we show that global decreases in surface ozone concentrations, due to methane mitigation, result in substantial and widespread decreases in premature human mortality. Reducing global anthropogenic methane emissions by 20% beginning in 2010 would decrease the average daily maximum 8-h surface ozone by approximately 1 part per billion by volume globally. By using epidemiologic ozone-mortality relationships, this ozone reduction is estimated to prevent approximately 30,000 premature all-cause mortalities globally in 2030, and approximately 370,000 between 2010 and 2030. If only cardiovascular and respiratory mortalities are considered, approximately 17,000 global mortalities can be avoided in 2030. The marginal cost-effectiveness of this 20% methane reduction is estimated to be approximately 420,000 US dollars per avoided mortality. If avoided mortalities are valued at 1 US dollars million each, the benefit is approximately 240 US dollars per tone of CH(4) ( approximately 12 US dollars per tone of CO(2) equivalent), which exceeds the marginal cost of the methane reduction. These estimated air pollution ancillary benefits of climate-motivated methane emission reductions are comparable with those estimated previously for CO(2). Methane mitigation offers a unique opportunity to improve air quality globally and can be a cost-effective component of international ozone management, bringing multiple benefits for air quality, public health, agriculture, climate, and energy.

  12. Ozone distributions over southern Lake Michigan: comparisons between ferry-based observations, shoreline-based DOAS observations and air quality forecast models

    NASA Astrophysics Data System (ADS)

    Cleary, P. A.; Fuhrman, N.; Schulz, L.; Schafer, J.; Fillingham, J.; Bootsma, H.; Langel, T.; Williams, E. J.; Brown, S. S.

    2014-09-01

    Air quality forecast models typically predict large ozone abundances over water relative to land in the Great Lakes region. While each state bordering Lake Michigan has dedicated monitoring systems, offshore measurements have been sparse, mainly executed through specific short-term campaigns. This study examines ozone abundances over Lake Michigan as measured on the Lake Express ferry, by shoreline Differential Optical Absorption Spectroscopy (DOAS) observations in southeastern Wisconsin, and as predicted by the National Air Quality Forecast System. From 2008-2009 measurements of O3, SO2, NO2 and formaldehyde were made in the summertime by DOAS at a shoreline site in Kenosha, WI. From 2008-2010 measurements of ambient ozone conducted on the Lake Express, a high-speed ferry that travels between Milwaukee, WI and Muskegon, MI up to 6 times daily from spring to fall. Ferry ozone observations over Lake Michigan were an average of 3.8 ppb higher than those measured at shoreline in Kenosha with little dependence on position of the ferry or temperature but with highest differences during evening and night. Concurrent ozone forecast images from National Weather System's National Air Quality Forecast System in the upper Midwestern region surrounding Lake Michigan were saved over the ferry ozone sampling period in 2009. The bias of the model O3 forecast was computed and evaluated with respect to ferry-based measurements. The model 1 and 8 h ozone mean biases were both 12 ppb higher than observed ozone, and maximum daily 1 h ozone mean bias was 10 ppb, indicating substantial ozone over-prediction over water. Trends in the bias with respect to location and time of day or month were also explored showing non-uniformity in model bias. Extreme ozone events were predicted by the model but not observed by ferry measurements.

  13. The Influence of European Pollution on Ozone in the Near East and Northern Africa

    NASA Technical Reports Server (NTRS)

    Duncan, B. N.; West, J. J.; Yoshida, Y.; Fiore, A. M.; Ziemke, J. R.

    2008-01-01

    We present a modeling study of the long-range transport of pollution from Europe, showing that European emissions regularly elevate surface ozone by as much as 20 ppbv in summer in northern Africa and the Near East. European emissions cause 50-150 additional violations per year (i.e. above those that would occur without European pollution) of the European health standard for ozone (8-h average greater than 120 micrograms per cubic meters or approximately 60 ppbv) in northern Africa and the Near East. We estimate that European ozone pollution is responsible for 50 000 premature mortalities globally each year, of which the majority occurs outside of Europe itself, including 37% (19 000) in northern Africa and the Near East. Much of the pollution from Europe is exported southward at low altitudes in summer to the Mediterranean Sea, northern Africa and the Near East, regions with favorable photochemical environments for ozone production. Our results suggest that assessments of the human health benefits of reducing ozone precursor emissions in Europe should include effects outside of Europe, and that comprehensive planning to improve air quality in northern Africa and the Near East likely needs to address European emissions.

  14. Tropospheric ozone in the vicinity of the ozone hole: 1987 Airborne Antarctic Ozone Experiment

    SciTech Connect

    Gregory, G.L.; Warren, L.S. ); Hypes, W.D. ); Tuck, A.F.; Kelly, K.K. ); Krueger, A.J. )

    1989-11-30

    Tropospheric ozone measurements over Antarctica aboard the NASA DC-8 aircraft are summarized. As part of the August/September 1987 Airborne Antarctic Ozone Experiment, the aircraft flew 13 missions covering a latitude of 53{degree}-90{degree}S, at altitudes to 13 km. Ozone mixing ratios as high as several hundred parts per billion by volume (ppbv) were measured, but in all cases these ratios were observed in pockets or patches of upper atmospheric air. These pockets were observed both in the vicinity of and away from the location of the ozone hole. At times, and as a result of these pockets, the ozone levels at the flight altitude of the aircraft, as averaged beneath the boundaries of the stratospheric ozone hole, were 2-3 times higher than background tropospheric values. The data suggest that the ozone-rich air seldom penetrated below about 9-km altitude. Background ozone values in the surrounding troposphere were typically in the range of 20-50 ppbv. Correlation of tropospheric ozone observations with the boundaries of the ozone hole differed during the experiment. During the early flights (August 28 through September 2), encounters with ozone-rich air were limited and background tropospheric ozone (at the flight altitude) appeared to decrease beneath the hole. For many of the later flights, and as the hole deepened, the reverse was noted, in that ozone-rich air was frequently observed in the vicinity of the hole and, as noted earlier, average ozone at the flight altitude was frequently higher than background values.

  15. The weekend effect within and downwind of Sacramento: Part 1. Observations of ozone, nitrogen oxides, and VOC reactivity

    NASA Astrophysics Data System (ADS)

    Murphy, J. G.; Day, D. A.; Cleary, P. A.; Wooldridge, P. J.; Millet, D. B.; Goldstein, A. H.; Cohen, R. C.

    2006-11-01

    Day-of-week patterns in human activities can be used to examine the ways in which differences in primary emissions result in changes in the rates of photochemical reactions, and the production of secondary pollutants. Data from twelve California Air Resources Board monitoring sites in Sacramento, CA, and the downwind Mountain Counties air basin are analyzed to reveal day of week patterns in ozone and its precursors in the summers of 1998-2002. This routine monitoring data is complemented by comprehensive data sets of ozone and nitrogen oxide concentrations and VOC reactivity obtained in the summers of 2001 and 2003 at three sites in the region. Daytime concentrations of nitrogen oxides (NOx) are approximately 35% lower on weekends at all the sites, whereas the VOC reactivity changes by less than 10%. All six sites in the Sacramento Valley have higher 8-h maximum average ozone on the weekend and are more likely to exceed the national standard of 85 ppb on the weekend. In contrast, all the sites in the Mountain Counties are less likely to exceed the federal ozone standard on the weekend. Analysis of the day-of-week trends in odd oxygen show that the weekend effect of ozone within Sacramento is strongly influenced by NO sources close to the monitoring sites. This suggests that ozone measurements from monitoring sites close to highways, including two rural locations, may not be representative of the regional abundance, and lead to underestimates of long term exposure for humans and ecosystems.

  16. Quaternion Averaging

    NASA Technical Reports Server (NTRS)

    Markley, F. Landis; Cheng, Yang; Crassidis, John L.; Oshman, Yaakov

    2007-01-01

    Many applications require an algorithm that averages quaternions in an optimal manner. For example, when combining the quaternion outputs of multiple star trackers having this output capability, it is desirable to properly average the quaternions without recomputing the attitude from the the raw star tracker data. Other applications requiring some sort of optimal quaternion averaging include particle filtering and multiple-model adaptive estimation, where weighted quaternions are used to determine the quaternion estimate. For spacecraft attitude estimation applications, derives an optimal averaging scheme to compute the average of a set of weighted attitude matrices using the singular value decomposition method. Focusing on a 4-dimensional quaternion Gaussian distribution on the unit hypersphere, provides an approach to computing the average quaternion by minimizing a quaternion cost function that is equivalent to the attitude matrix cost function Motivated by and extending its results, this Note derives an algorithm that deterniines an optimal average quaternion from a set of scalar- or matrix-weighted quaternions. Rirthermore, a sufficient condition for the uniqueness of the average quaternion, and the equivalence of the mininiization problem, stated herein, to maximum likelihood estimation, are shown.

  17. Nqrs Data for C8H9KO6 [C8H5KO4·2(H2O)] (Subst. No. 1092)

    NASA Astrophysics Data System (ADS)

    Chihara, H.; Nakamura, N.

    This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C8H9KO6 [C8H5KO4·2(H2O)] (Subst. No. 1092)

  18. Calculations of Polar Ozone Loss Rates

    NASA Technical Reports Server (NTRS)

    Dessler, A. E.; Wu, J.

    1999-01-01

    We calculate vortex-averaged ozone loss rates at 465-K potential temperature during the Aug.-Sept. time period in the southern hemisphere and Feb.-Mar. time period in the northern hemisphere. Ozone loss rates are calculated two ways. First, from the time series of measurements of 03. Second, from measurements of ClO, from which ozone loss is inferred based on our theories of Cl-catalyzed ozone destruction. Both measurement sets are from the Upper Atmosphere Research Satellite (UARS) Microwave Limb Sounder (MLS) instrument. We find good agreement between vortex-averaged ozone loss rates calculated from these methods. Our analysis provides no support for recent work suggesting that current theories of Cl-catalyzed ozone loss underestimate the observed decrease in polar ozone during the ozone "hole" period.

  19. [Responses of rice growth and development to elevated near-surface layer ozone (O3) concentration: a review].

    PubMed

    Yang, Lian-xin; Wang, Yu-long; Shi, Guang-yao; Wang, Yun-xia; Zhu, Jian-guo

    2008-04-01

    Ozone (O3) is recognized as one of the most important air pollutants. At present, the worldwide average tropospheric O3 concentration has been increased from an estimated pre-industrial level of 38 nl L(-1) (25-45 nl L(-1), 8-h summer seasonal average) to approximately 50 nl L(-1) in 2000, and to 80 nl L(-1) by 2100 based on most pessimistic projections. Oryza sativa L. (rice) is the most important grain crop in the world, and thus, to correctly evaluate how the elevated near-surface layer O3 concentration will affect the growth and development of rice is of great significance. This paper reviewed the chamber (including closed and open top chamber)-based studies about the effects of atmospheric ozone enrichment on the rice visible injury symptoms, photosynthesis, water relationship, phenology, dry matter production and allocation, leaf membrane protective system, and grain yield and its components. Further research directions in this field were discussed.

  20. The 1990 Antarctic ozone hole as observed by TOMS. [Total Ozone Mapping Spectrometer

    SciTech Connect

    Newman, P.; Stolarski, R.; Schoeberl, M.; McPeters, R.; Krueger, A.

    1991-04-01

    The 1990 Antarctic ozone hole matched the record 1987 ozone hole in depth, duration, and area. During the formation phase of the hole (August), total ozone values were the lowest yet recorded. The decline rate approximately matched the record 1987 decline, and reached a minimum of 125 Dobson Units on October 4, 1990. October total ozone averages were marginally higher than 1987. As during 1987, the 1990 total ozone values within the hole slowly and steadily increased during the mid-October through November period. The ozone hole breakup was the latest yet recorded (early December), with low ozone values persisting over the pole through December, setting a record low for December average polar ozone. Temperatures were near average during the early spring, but were below normal for the late-spring. Temperatures in the early spring of 1990 were substantially warmer than those observed in the early spring of 1987.

  1. The 1990 Antarctica ozone hole as observed by TOMS. [Total Ozone Mapping Spectrometer

    NASA Technical Reports Server (NTRS)

    Newman, Paul; Stolarski, Richard; Schoeberl, Mark; Mcpeters, Richard; Krueger, Arlin

    1991-01-01

    The 1990 Antarctic ozone hole matched the record 1987 ozone hole in depth, duration, and area. During the formation phase of the hole (August), total ozone values were the lowest yet recorded. The decline rate approximately matched the record 1987 decline and reached a minimum of 125 Dobson Units on October 4, 1990. October total ozone averages were marginally higher that 1987. As during 1987, the 1990 total ozone values within the hole slowly and steadily increased during the mid-October through November period. The ozone hole breakup was the latest yet recorded (early December), with low ozone values persisting over the pole through December, setting a record low for December average polar ozone. Temperatures were near average during the early spring, but were below normal for the late spring. Temperatures in the early spring of 1990 were substantially warmer than those observed in the early spring of 1987.

  2. Impact of downward-mixing ozone on surface ozone accumulation in southern Taiwan.

    PubMed

    Lin, Ching-Ho

    2008-04-01

    The ozone that initially presents in the previous day's afternoon mixing layer can remain in the nighttime atmosphere and then be carried over to the next morning. Finally, this ozone can be brought to the ground by downward mixing as mixing depth increases during the daytime, thereby increasing surface ozone concentrations. Variation of ozone concentration during each of these periods is investigated in this work. First, ozone concentrations existing in the daily early morning atmosphere at the altitude range of the daily maximum mixing depth (residual ozone concentrations) were measured using tethered ozonesondes on 52 experimental days during 2004-2005 in southern Taiwan. Daily downward-mixing ozone concentrations were calculated by a box model coupling the measured daily residual ozone concentrations and daily mixing depth variations. The ozone concentrations upwind in the previous day's afternoon mixing layer were estimated by the combination of back air trajectory analysis and known previous day's surface ozone distributions. Additionally, the relationship between daily downward-mixing ozone concentration and daily photochemically produced ozone concentration was examined. The latter was calculated by removing the former from daily surface maximum ozone concentration. The measured daily residual ozone concentrations distributed at 12-74 parts per billion (ppb) with an average of 42 +/- 17 ppb are well correlated with the previous upwind ozone concentration (R2 = 0.54-0.65). Approximately 60% of the previous upwind ozone was estimated to be carried over to the next morning and became the observed residual ozone. The daily downward-mixing ozone contributes 48 +/- 18% of the daily surface maximum ozone concentration, indicating that the downward-mixing ozone is as important as daily photochemically produced ozone to daily surface maximum ozone accumulation. The daily downward-mixing ozone is poorly correlated with the daily photochemically produced ozone and

  3. Regional ozone impacts of increased natural gas use in the Texas power sector and development in the Eagle Ford shale.

    PubMed

    Pacsi, Adam P; Kimura, Yosuke; McGaughey, Gary; McDonald-Buller, Elena C; Allen, David T

    2015-03-17

    The combined emissions and air quality impacts of electricity generation in the Texas grid and natural gas production in the Eagle Ford shale were estimated at various natural gas price points for the power sector. The increased use of natural gas in the power sector, in place of coal-fired power generation, drove reductions in average daily maximum 8 h ozone concentration of 0.6-1.3 ppb in northeastern Texas for a high ozone episode used in air quality planning. The associated increase in Eagle Ford upstream oil and gas production nitrogen oxide (NOx) emissions caused an estimated local increase, in south Texas, of 0.3-0.7 ppb in the same ozone metric. In addition, the potential ozone impacts of Eagle Ford emissions on nearby urban areas were estimated. On the basis of evidence from this work and a previous study on the Barnett shale, the combined ozone impact of increased natural gas development and use in the power sector is likely to vary regionally and must be analyzed on a case by case basis.

  4. Regional ozone impacts of increased natural gas use in the Texas power sector and development in the Eagle Ford shale.

    PubMed

    Pacsi, Adam P; Kimura, Yosuke; McGaughey, Gary; McDonald-Buller, Elena C; Allen, David T

    2015-03-17

    The combined emissions and air quality impacts of electricity generation in the Texas grid and natural gas production in the Eagle Ford shale were estimated at various natural gas price points for the power sector. The increased use of natural gas in the power sector, in place of coal-fired power generation, drove reductions in average daily maximum 8 h ozone concentration of 0.6-1.3 ppb in northeastern Texas for a high ozone episode used in air quality planning. The associated increase in Eagle Ford upstream oil and gas production nitrogen oxide (NOx) emissions caused an estimated local increase, in south Texas, of 0.3-0.7 ppb in the same ozone metric. In addition, the potential ozone impacts of Eagle Ford emissions on nearby urban areas were estimated. On the basis of evidence from this work and a previous study on the Barnett shale, the combined ozone impact of increased natural gas development and use in the power sector is likely to vary regionally and must be analyzed on a case by case basis. PMID:25723953

  5. Protecting beans from ozone

    SciTech Connect

    Pierce, R.

    1983-03-01

    A chemical treatment to protect navy beans from ozone damage increased yields by an average of more than 20% in 3 years of tests. An experimental antioxidant chemical, EDU, made by the DuPont company was tested as soil applications and sprays on several varieties and under a variety of soil and planting conditions. The average yield increases were between 16 and 24%. Chemical treatment also increased snap bean pod production by 12%.

  6. Effects of plug-in hybrid electric vehicles on ozone concentrations in Colorado.

    PubMed

    Brinkman, Gregory L; Denholm, Paul; Hannigan, Michael P; Milford, Jana B

    2010-08-15

    This study explores how ozone concentrations in the Denver, CO area might have been different if plug-in hybrid electric vehicles (PHEVs) had replaced light duty gasoline vehicles in summer 2006. A unit commitment and dispatch model was used to estimate the charging patterns of PHEVs and dispatch power plants to meet electricity demand. Emission changes were estimated based on gasoline displacement and the emission characteristics of the power plants providing additional electricity. The Comprehensive Air Quality Model with extensions (CAMx) was used to simulate the effects of these emissions changes on ozone concentrations. Natural gas units provided most of the electricity used for charging PHEVs in the scenarios considered. With 100% PHEV penetration, nitrogen oxide (NO(x)) emissions were reduced by 27 tons per day (tpd) from a fleet of 1.7 million vehicles and were increased by 3 tpd from power plants; VOC emissions were reduced by 57 tpd. These emission changes reduced modeled peak 8-h average ozone concentrations by approximately 2-3 ppb on most days. Ozone concentration increases were modeled for small areas near central Denver. Future research is needed to forecast when significant PHEV penetration may occur and to anticipate characteristics of the corresponding power plant and vehicle fleets.

  7. Chemistry and Dynamics of the Unusual 2015 Antarctic Ozone Hole

    NASA Astrophysics Data System (ADS)

    Braathen, Geir O.

    2016-04-01

    The Global Atmosphere Watch of the World Meteorological Organization includes several stations in Antarctica that keep a close eye on the ozone layer during the ozone hole season. Observations made during the unusually large ozone hole of 2015 will be compared to ozone holes from 2003 to 2014 and interpreted in light of the meteorological conditions. Satellite observations will be used to get a more general picture of the size and depth of the ozone hole and will also be used to calculate various metrics for ozone hole severity. In 2003, 2005 and 2006, the ozone hole was relatively large with more ozone loss than normal. This is in particular the case for 2006, which by most ozone hole metrics was the most severe ozone hole on record. On the other hand, the ozone holes of 2004, 2007, 2010 and 2012, 2013 and 2014 were less severe than normal, and only the very special ozone hole of 2002 had less ozone depletion when one regards the ozone holes of the last decade. The South Polar vortex of 2015 was unusually stable and long-lived, so ozone depletion lasted longer than seen in recent years. The ozone hole area, i.e. the area where total ozone is less that 220 DU, averaged over the worst 60 consecutive days was larger in 2015 than in any other year since the beginning of the ozone hole era in the early 1980s.

  8. Ozone decomposition

    PubMed Central

    Batakliev, Todor; Georgiev, Vladimir; Anachkov, Metody; Rakovsky, Slavcho

    2014-01-01

    Catalytic ozone decomposition is of great significance because ozone is a toxic substance commonly found or generated in human environments (aircraft cabins, offices with photocopiers, laser printers, sterilizers). Considerable work has been done on ozone decomposition reported in the literature. This review provides a comprehensive summary of the literature, concentrating on analysis of the physico-chemical properties, synthesis and catalytic decomposition of ozone. This is supplemented by a review on kinetics and catalyst characterization which ties together the previously reported results. Noble metals and oxides of transition metals have been found to be the most active substances for ozone decomposition. The high price of precious metals stimulated the use of metal oxide catalysts and particularly the catalysts based on manganese oxide. It has been determined that the kinetics of ozone decomposition is of first order importance. A mechanism of the reaction of catalytic ozone decomposition is discussed, based on detailed spectroscopic investigations of the catalytic surface, showing the existence of peroxide and superoxide surface intermediates. PMID:26109880

  9. Ozone decomposition.

    PubMed

    Batakliev, Todor; Georgiev, Vladimir; Anachkov, Metody; Rakovsky, Slavcho; Zaikov, Gennadi E

    2014-06-01

    Catalytic ozone decomposition is of great significance because ozone is a toxic substance commonly found or generated in human environments (aircraft cabins, offices with photocopiers, laser printers, sterilizers). Considerable work has been done on ozone decomposition reported in the literature. This review provides a comprehensive summary of the literature, concentrating on analysis of the physico-chemical properties, synthesis and catalytic decomposition of ozone. This is supplemented by a review on kinetics and catalyst characterization which ties together the previously reported results. Noble metals and oxides of transition metals have been found to be the most active substances for ozone decomposition. The high price of precious metals stimulated the use of metal oxide catalysts and particularly the catalysts based on manganese oxide. It has been determined that the kinetics of ozone decomposition is of first order importance. A mechanism of the reaction of catalytic ozone decomposition is discussed, based on detailed spectroscopic investigations of the catalytic surface, showing the existence of peroxide and superoxide surface intermediates. PMID:26109880

  10. Polar ozone

    NASA Technical Reports Server (NTRS)

    Solomon, S.; Grose, W. L.; Jones, R. L.; Mccormick, M. P.; Molina, Mario J.; Oneill, A.; Poole, L. R.; Shine, K. P.; Plumb, R. A.; Pope, V.

    1990-01-01

    The observation and interpretation of a large, unexpected ozone depletion over Antarctica has changed the international scientific view of stratospheric chemistry. The observations which show the veracity, seasonal nature, and vertical structure of the Antarctic ozone hole are presented. Evidence for Arctic and midlatitude ozone loss is also discussed. The chemical theory for Antarctic ozone depletion centers around the occurrence of polar stratospheric clouds (PSCs) in Antarctic winter and spring; the climatology and radiative properties of these clouds are presented. Lab studies of the physical properties of PSCs and the chemical processes that subsequently influence ozone depletion are discussed. Observations and interpretation of the chemical composition of the Antarctic stratosphere are described. It is shown that the observed, greatly enhanced abundances of chlorine monoxide in the lower stratosphere are sufficient to explain much if not all of the ozone decrease. The dynamic meteorology of both polar regions is given, interannual and interhemispheric variations in dynamical processes are outlined, and their likely roles in ozone loss are discussed.

  11. Ozone decomposition.

    PubMed

    Batakliev, Todor; Georgiev, Vladimir; Anachkov, Metody; Rakovsky, Slavcho; Zaikov, Gennadi E

    2014-06-01

    Catalytic ozone decomposition is of great significance because ozone is a toxic substance commonly found or generated in human environments (aircraft cabins, offices with photocopiers, laser printers, sterilizers). Considerable work has been done on ozone decomposition reported in the literature. This review provides a comprehensive summary of the literature, concentrating on analysis of the physico-chemical properties, synthesis and catalytic decomposition of ozone. This is supplemented by a review on kinetics and catalyst characterization which ties together the previously reported results. Noble metals and oxides of transition metals have been found to be the most active substances for ozone decomposition. The high price of precious metals stimulated the use of metal oxide catalysts and particularly the catalysts based on manganese oxide. It has been determined that the kinetics of ozone decomposition is of first order importance. A mechanism of the reaction of catalytic ozone decomposition is discussed, based on detailed spectroscopic investigations of the catalytic surface, showing the existence of peroxide and superoxide surface intermediates.

  12. Selected Measurements of Total Arctic Column Ozone Amounts from Aura's Ozone Monitoring Instrument,

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Images from Aura's Ozone Monitoring Instrument showing the average total column ozone during the months of January and March, and the total column ozone on the single day of 11 March. Although there was near record chemical ozone loss between January and March, comparing the January and March images shows that on average the lowest total column ozone values in polar regions are slightly higher in March than in January. This is because of the other process that brought higher ozone into the vortex region, thus compensating for the very significant chemical loss. The 11 March image shows that, despite the unremarkable overall March values, on an individual day, chemical loss and dynamical processes combined to result in localized regions of much lower ozone (which resulted in higher UV exposure at the Earth's surface for individual days and places).

  13. Ozone variability

    NASA Astrophysics Data System (ADS)

    Duetsch, H. U.

    1983-09-01

    The annual and long-term variations in the atmospheric ozone layer were examined on the basis of 55 yr of data taken at Aroya, Switzerland and 25 yr of data gathered by the global ozone network. Attention was given to annual and biennial variations, which showed that the midlatitude peak concentration was affected by a quasi-biennial variation of the tropical stratospheric circulation. Smaller scale circulation patterns were dominant in the lower stratosphere, although an observed negative trend of the total ozone was equally distributed between the troposphere and 24 km altitude. The global ozone increase detected in the 1960s was possible due to general circulation alterations, but may also have been influenced by injection of NO(x) into the atmosphere during atomic bomb testing.

  14. 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.

  15. Is There an Arctic Ozone Hole?

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.

    2000-01-01

    Total ozone observations from the Total Ozone Mapping Spectrometer (TOMS) instruments during March 1997 revealed an extensive region of low column densities in the Arctic region centered near the north pole. Values were below 250 Dobson units for nearly a two week period during this period, and were correlated with the position of the northern lower stratospheric polar vortex. The March 1997 average total ozone column densities were more than 30% lower than the average of column densities observed during the 1979-1982 March period. Both the northern spring seasons of 1998 and 1999 have shown much higher levels of total ozone. In this presentation, we will discuss the causes of the low total ozone values in 1997 and contrast those low values with the higher 1998 and 1999 observations. I will additionally discuss the just completed SOLVE campaign and the March 2000 ozone values.

  16. The threee-dimensional morphology of the Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Aikin, Arthur C.; Mcpeters, R. D.

    1988-01-01

    The three-dimensional morphology of the spring antarctic ozone distribution as determined by the Nimbus 7 Solar Backscatter Ultraviolet (SBUV) spectrometer instrument is presented for the period 1 to 11 October in 1986. The data show that a clearly defined minimum in ozone relative to the local ozone field extends throughout the stratosphere from the tropopause to above 50 km, though decreasing in intensity with altitude. Near 18 km ozone in the ozone hole is 50 percent less than the average surrounding ozone. But even at 50 km the ozone is 20 percent less than the surrounding ozone field. The ozone minimum in the upper stratosphere is displaced about 6 degrees toward the equator so that observations at a fixed station may provide the illusion that the ozone minimum is restricted only to low altitudes. While the ozone minimum is spatially coherent throughout the stratosphere, there are differences in the behavior of ozone at different altitudes that suggest the existence of at least three distinct altitude domains. Below 30 km ozone is characterized by classic ozone hole behavior. Between 33 and 43 km ozone is more stable, actually increasing during September and October. Above 43 km ozone has always decreased during September to a minimum in October, but it has suffered a long term decrease of 7 to 12 percent since 1979 similar to that seen at low altitudes.

  17. Laboratory spectroscopy of the C{sub 7}H and C{sub 8}H radicals

    SciTech Connect

    McCarthy, M.C.; Travers, M.J.; Thaddeus, P.

    1996-12-31

    The linear carbon chain radicals C{sub 7}H and C{sub 8}H have been detected in their {sup 2}{Pi} electronic ground states in an acetylene/argon discharge. For each radical, both spin-orbit components have been detected, precise values for the rotational, fine structure, and lambda-doubling constants determined, and the entire fine structure rotational spectrum calculated. The lowest rotational transitions of C{sub 7}H and C{sub 8}H were also observed in a pulsed discharge supersonic molecular beam source by Fourier transform microwave spectroscopy. A summary of results, including an analysis of the hyperfine structure will be presented.

  18. Low-temperature photoluminescence of 8H-SiC homoepitaxial layer

    NASA Astrophysics Data System (ADS)

    Hatayama, Tomoaki; Henry, Anne; Yano, Hiroshi; Fuyuki, Takashi

    2016-02-01

    Low-temperature photoluminescence of a nitrogen-doped 8H-SiC epilayer homoepitaxially grown by a chemical vapor deposition method is reported. The polytype and stacking sequence of the epilayers were confirmed by transmission electron microscopy analyses. The identification of emission lines is discussed in terms of the temperature dependence of the luminescence spectra. Luminescence related to the free excitons and the nitrogen-bound excitons is observed, which allows the determination of the excitonic bandgap of the 8H-SiC polytype. In addition, the low binding energies found for the nitrogen-bound excitons imply shallow levels for the nitrogen donors.

  19. Options to accelerate ozone recovery: ozone and climate benefits

    NASA Astrophysics Data System (ADS)

    Daniel, J. S.; Fleming, E. L.; Portmann, R. W.; Velders, G. J. M.; Jackman, C. H.; Ravishankara, A. R.

    2010-08-01

    Hypothetical reductions in future emissions of ozone-depleting substances (ODSs) and N2O are evaluated in terms of effects on equivalent effective stratospheric chlorine (EESC), globally-averaged total column ozone, and radiative forcing through 2100. Due to the established success of the Montreal Protocol, these actions can have only a fraction of the impact on ozone depletion that regulations already in force have had. If all anthropogenic ODS and N2O emissions were halted beginning in 2011, ozone is calculated to be higher by about 1-2% during the period 2030-2100 compared to a case of no additional restrictions. Direct radiative forcing by 2100 would be about 0.23 W/m2 lower from the elimination of anthropogenic N2O emissions and about 0.005 W/m2 lower from the destruction of the chlorofluorocarbon (CFC) bank. Due to the potential impact of N2O on future ozone levels, we provide an approach to incorporate it into the EESC formulation, which is used extensively in ozone depletion analyses. The ability of EESC to describe total ozone changes arising from additional ODS and N2O controls is also quantified.

  20. Trends in ozone profile measurements

    NASA Technical Reports Server (NTRS)

    Johnston, H.; Aikin, A.; Barnes, R.; Chandra, S.; Cunnold, D.; Deluisi, J.; Gille, J. C.; Hudson, R.; Mccormick, M. P.; Mcmaster, L.

    1989-01-01

    From an examination of the agreements and differences between different satellite instruments, it is difficult to believe that existing satellite instruments determine upper stratospheric ozone much better than 4 pct.; by extension, it probably would require at least a 4 pct. change to be reliably detected as a change. The best estimates of the vertical profiles of ozone change in the upper stratosphere between 1979 and 1986 are judged to be those given by the two SAGE satellite instruments. SAGE-2 minus SAGE-1 gives a much lower ozone reduction than that given by the archived Solar Backscatter UV data. The average SAGE profiles of ozone changes between 20 and 50 degs north and between 20 and 50 degs south are given. The SAGE-1 and SAGE-2 comparison gives an ozone reduction of about 4 pct. at 25 km over temperate latitudes. Five ground based Umkehr stations between 36 and 52 degs north, corrected for the effects of volcanic aerosols, report an ozone reduction between 1979 and 1987 at Umkehr layer 8 of 9 + or - 5 pct. The central estimate of upper stratospheric ozone reduction given by SAGE at 40 km is less than the central value estimated by the Umkehr method at layer 8.

  1. NQRS Data for C8H9DO (Subst. No. 1091)

    NASA Astrophysics Data System (ADS)

    Chihara, H.; Nakamura, N.

    This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C8H9DO (Subst. No. 1091)

  2. European characterization factors for human health damage of PM 10 and ozone in life cycle impact assessment

    NASA Astrophysics Data System (ADS)

    van Zelm, Rosalie; Huijbregts, Mark A. J.; den Hollander, Henri A.; van Jaarsveld, Hans A.; Sauter, Ferd J.; Struijs, Jaap; van Wijnen, Harm J.; van de Meent, Dik

    This paper presents characterization factors (CFs) for human health effects of fine particulate (PM 10) and ozone in Europe for the purpose of life cycle impact assessment. The CFs express the change in disability adjusted life years (DALYs) of European inhabitants due to a change in emissions of PM 10, ammonia (NH 3), nitrogen oxides (NO x), sulfur dioxide (SO 2), and non-methane volatile organic compounds (NMVOCs). The CF consists of an intake factor, an effect factor, and a damage factor. The intake factor was modeled as the change in population exposure to primary and secondary aerosols, and ozone due to a change in emission of a substance. This was done with the models EUTREND (aerosols) and LOTOS-EUROS (ozone). A combined human effect and damage factor, represented by the change in DALY due to a change in population intake was derived from epidemiological-based relative risks of short-term mortality, long-term mortality, and morbidity. Primary PM 10 causes 260 DALYs per kton emission, while secondary aerosol formation results in CFs between 51 and 83 DALYs per kton of precursor emitted. Applying CFs for high and low stack sources separately for PM 10 and SO 2 life cycle emissions can lead to a better estimation of human health damage due to these pollutants. CF related to ozone formation emissions appear to be much lower (0.04 DALY per kton, calculated based on maximum daily 8-h average ozone concentration) compared to the CF for primary and secondary PM 10. When calculating CF based on 24-h average ozone concentration, NMVOC causes 0.04 DALYs per kton, while the CF for NO x causing ozone formation is negative due to reactivity of ozone with NO in areas with high NO x levels (-0.12 DALYs per kton). Total European emissions of the five priority air pollutants in year 2000 are attributed to 4.2 million DALYs for the European population, which corresponds on average to 0.25 DALYs per person over a lifetime (80 years).

  3. Observations of the Antarctic Ozone Hole from 2003 to 2014

    NASA Astrophysics Data System (ADS)

    Braathen, Geir O.

    2015-04-01

    The Global Atmosphere Watch of WMO includes several stations in Antarctica that keep a close eye on the ozone layer during the ozone hole season. Observations made during the ozone holes from 2003 to 2014 will be compared to each other and interpreted in light of the meteorological conditions. Satellite observations will be used to get a more general picture of the size and depth of the ozone hole and will also be used to calculate various metrics for ozone hole severity. In 2003, 2005 and 2006, the ozone hole was relatively large with more ozone loss than normal. This is in particular the case for 2006, which by most ozone hole metrics was the most severe ozone hole on record. On the other hand, the ozone holes of 2004, 2007, 2010 and 2012 were less severe than normal, and only the very special ozone hole of 2002 had less ozone depletion when one regards the ozone holes of the last decade. The ozone hole of 2011 suffered more ozone depletion than in 2010, but it was quite average in comparison to other years of the last decade. The situation was similar in 2013 and 2014. The interannual variability will be discussed with the help of meteorological data, such as temperature conditions, possibility for polar stratospheric clouds, vortex shape and vortex longevity.

  4. Observations of the Antarctic Ozone Hole from 2003 to 2013

    NASA Astrophysics Data System (ADS)

    Braathen, Geir O.

    2014-05-01

    The Global Atmosphere Watch of WMO includes several stations in Antarctica that keep a close eye on the ozone layer during the ozone hole season. Observations made during the ozone holes from 2003 to 2013 will be compared to each other and interpreted in light of the meteorological conditions. Satellite observations will be used to get a more general picture of the size and depth of the ozone hole and will also be used to calculate various metrics for ozone hole severity. In 2003, 2005 and 2006, the ozone hole was relatively large with more ozone loss than normal. This is in particular the case for 2006, which by most ozone hole metrics was the most severe ozone hole on record. On the other hand, the ozone holes of 2004, 2007, 2010 and 2012 were less severe than normal, and only the very special ozone hole of 2002 had less ozone depletion when one regards the ozone holes of the last decade. The ozone hole of 2011 suffered more ozone depletion than in 2010, but it was quite average in comparison to other years of the last decade. The situation was similar in 2013. The interannual variability will be discussed with the help of meteorological data, such as temperature conditions, possibility for polar stratospheric clouds, vortex shape and vortex longevity. Observations will also be compared to 3-D chemical transport model calculations.

  5. The weekend effect within and downwind of Sacramento - Part 1: Observations of ozone, nitrogen oxides, and VOC reactivity

    NASA Astrophysics Data System (ADS)

    Murphy, J. G.; Day, D. A.; Cleary, P. A.; Wooldridge, P. J.; Millet, D. B.; Goldstein, A. H.; Cohen, R. C.

    2007-10-01

    Day-of-week patterns in human activities can be used to examine the ways in which differences in primary emissions result in changes in the rates of photochemical reactions, and the production of secondary pollutants. Data from twelve California Air Resources Board monitoring sites in Sacramento, CA, and the downwind Mountain Counties air basin are analyzed to reveal day of week patterns in ozone and its precursors in the summers of 1998-2002. Measurements of non-methane hydrocarbons are available for the summers of 2001-2003 at three of these sites and NOx at six of these sites for the full time period. This routine monitoring data is complemented by data sets of ozone and nitrogen oxide concentrations obtained in the summers of 2001 and 2003 at three sites in the region and comprehensive measurements of VOC reactivity at two sites in 2001. Daytime concentrations of nitrogen oxides (NOx≡NO+NO2) are approximately 35% lower on weekends at all the sites, whereas the VOC reactivity changes by less than 10%. All six sites in the Sacramento Valley have higher 8-h maximum average ozone on the weekend and are more likely to exceed the national standard of 85 ppb on the weekend. In contrast, all the sites in the Mountain Counties are less likely to exceed the federal ozone standard on the weekend. Analysis of the day-of-week trends in odd oxygen show that the weekend effect of ozone within Sacramento is strongly influenced by NO sources close to the monitoring sites. This suggests that ozone measurements from monitoring sites close to highways, including two rural locations, may not be representative of the regional abundance, and lead to underestimates of long term exposure for humans and ecosystems.

  6. Anthropogenic emissions in Nigeria and implications for atmospheric ozone pollution: A view from space

    NASA Astrophysics Data System (ADS)

    Marais, E. A.; Jacob, D. J.; Wecht, K.; Lerot, C.; Zhang, L.; Yu, K.; Kurosu, T. P.; Chance, K.; Sauvage, B.

    2014-12-01

    Nigeria has a high population density and large fossil fuel resources but very poorly managed energy infrastructure. Satellite observations of formaldehyde (HCHO) and glyoxal (CHOCHO) reveal very large sources of anthropogenic nonmethane volatile organic compounds (NMVOCs) from the Lagos megacity and oil/gas operations in the Niger Delta. This is supported by aircraft observations over Lagos and satellite observations of methane in the Niger Delta. Satellite observations of carbon monoxide (CO) and nitrogen dioxide (NO2) show large seasonal emissions from open fires in December-February (DJF). Ventilation of central Nigeria is severely restricted at that time of year, leading to very poor ozone air quality as observed from aircraft (MOZAIC) and satellite (TES). Simulations with the GEOS-Chem chemical transport model (CTM) suggest that maximum daily 8-h average (MDA8) ozone exceeds 70 ppbv over the region on a seasonal mean basis, with significant contributions from both open fires (15-20 ppbv) and fuel/industrial emissions (7-9 ppbv). The already severe ozone pollution in Nigeria could worsen in the future as a result of demographic and economic growth, although this would be offset by a decrease in open fires.

  7. Quantitative characterization of the Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Ito, T.; Sakoda, Y.; Matsubara, K.; Takao, T.; Akagi, K.; Watanabe, Y.; Shibata, S.; Naganuma, H.

    1994-01-01

    The long-term evolution of the Antarctic ozone hole is studied based on the TOMS data and the JMA data-set of stratospheric temperature in relation with the possible role of polar stratospheric clouds (PSC's). The effective mass of depleted ozone in the ozone hole at its annual mature stage reached a historical maximum of 55 Mt in 1991, 4.3 times larger than in 1981. The ozone depletion rate during 30 days before the mature ozone hole does not show any appreciable long-term trend but the interannual fluctuations do, ranging from 0.169 to 0.689 Mt/day with the average of 0.419 Mt/day for the period of 1979 - 1991. The depleted ozone mass has the highest correlation with the region below 195 K on the 30 mb surface in June, whereas the ozone depletion rate correlates most strongly with that in August. The present result strongly suggests that the long-term evolution of the mature ozone hole is caused both by the interannual change of the latitudinal coverage of the early PSC's, which may control the latitude and date of initiation of ozone decrease, and by that of the spatial coverage of the mature PSC's which may control the ozone depletion rate in the Antarctic spring.

  8. Effects of stratospheric ozone recovery on tropospheric chemistry and air quality

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

    The stratospheric ozone has decreased greatly since 1980 due to ozone depleting substances (ODSs). As a result of 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. We examine the implications of stratospheric ozone recovery for the tropospheric chemistry and ozone air quality with a global chemical transport model (GEOS-Chem). Significant decreases in surface ozone photolysis rates due to stratospheric ozone recovery are simulated. Increases in ozone lifetime by up to 7% are calculated in the troposphere. The global average OH decreases by 1.74% and the global burden of tropospheric ozone increases by 0.78%. The perturbations to tropospheirc 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 5% for some regions.

  9. Impacts of Stratospheric Ozone Change on Tropospheric Chemistry and Air Quality

    NASA Astrophysics Data System (ADS)

    Wu, S.; Zhang, H.

    2013-05-01

    The stratospheric ozone has decreased greatly since 1980 due to ozone depleting substances (ODSs). As a result of 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. We examine the implications of stratospheric ozone recovery for the tropospheric chemistry and ozone air quality with a global chemical transport model (GEOS-Chem). Significant decreases in surface ozone photolysis rates due to stratospheric ozone recovery are simulated. Increases in ozone lifetime by up to 7% are calculated in the troposphere. The global average OH decreases by 1.74% and the global burden of tropospheric ozone increased by 0.78%. The perturbations to tropospheirc 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 5% for some regions.

  10. NQRS Data for C8H7Cl5NSb (Subst. No. 1082)

    NASA Astrophysics Data System (ADS)

    Chihara, H.; Nakamura, N.

    This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C8H7Cl5NSb (Subst. No. 1082)

  11. NQRS Data for C8H10BrN (Subst. No. 1096)

    NASA Astrophysics Data System (ADS)

    Chihara, H.; Nakamura, N.

    This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C8H10BrN (Subst. No. 1096)

  12. Nqrs Data for C8H12BCuF4N4 (Subst. No. 1102)

    NASA Astrophysics Data System (ADS)

    Chihara, H.; Nakamura, N.

    This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C8H12BCuF4N4 (Subst. No. 1102)

  13. Nqrs Data for C8H6O4 (Subst. No. 1074)

    NASA Astrophysics Data System (ADS)

    Chihara, H.; Nakamura, N.

    This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C8H6O4 (Subst. No. 1074)

  14. Nqrs Data for C8H7ClN2O3 (Subst. No. 1078)

    NASA Astrophysics Data System (ADS)

    Chihara, H.; Nakamura, N.

    This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C8H7ClN2O3 (Subst. No. 1078)

  15. NQRS Data for C8H20Br3GeN (Subst. No. 1129)

    NASA Astrophysics Data System (ADS)

    Chihara, H.; Nakamura, N.

    This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C8H20Br3GeN (Subst. No. 1129)

  16. NQRS Data for C8H7BrO (Subst. No. 1076)

    NASA Astrophysics Data System (ADS)

    Chihara, H.; Nakamura, N.

    This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C8H7BrO (Subst. No. 1076)

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

    SciTech Connect

    Pride, Kerry R.; Peel, Jennifer L.; Robinson, Byron F.; Busacker, Ashley; Grandpre, Joseph; Bisgard, Kristine M.; Yip, Fuyuen Y.; Murphy, Tracy D.

    2015-02-15

    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 for 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

  18. Assessing the impact of local meteorological variables on surface ozone in Hong Kong during 2000-2015 using quantile and multiple line regression models

    NASA Astrophysics Data System (ADS)

    Zhao, Wei; Fan, Shaojia; Guo, Hai; Gao, Bo; Sun, Jiaren; Chen, Laiguo

    2016-11-01

    The quantile regression (QR) method has been increasingly introduced to atmospheric environmental studies to explore the non-linear relationship between local meteorological conditions and ozone mixing ratios. In this study, we applied QR for the first time, together with multiple linear regression (MLR), to analyze the dominant meteorological parameters influencing the mean, 10th percentile, 90th percentile and 99th percentile of maximum daily 8-h average (MDA8) ozone concentrations in 2000-2015 in Hong Kong. The dominance analysis (DA) was used to assess the relative importance of meteorological variables in the regression models. Results showed that the MLR models worked better at suburban and rural sites than at urban sites, and worked better in winter than in summer. QR models performed better in summer for 99th and 90th percentiles and performed better in autumn and winter for 10th percentile. And QR models also performed better in suburban and rural areas for 10th percentile. The top 3 dominant variables associated with MDA8 ozone concentrations, changing with seasons and regions, were frequently associated with the six meteorological parameters: boundary layer height, humidity, wind direction, surface solar radiation, total cloud cover and sea level pressure. Temperature rarely became a significant variable in any season, which could partly explain the peak of monthly average ozone concentrations in October in Hong Kong. And we found the effect of solar radiation would be enhanced during extremely ozone pollution episodes (i.e., the 99th percentile). Finally, meteorological effects on MDA8 ozone had no significant changes before and after the 2010 Asian Games.

  19. Nanoscale assemblies of gigantic molecular {Mo154}-rings: (dimethyldioctadecylammonium)20[Mo154O462H8(H2O)70].

    PubMed

    Akutagawa, Tomoyuki; Jin, Reina; Tunashima, Ryo; Noro, Shin-Ichiro; Cronin, Leroy; Nakamura, Takayoshi

    2008-01-01

    Clusters based on the mixed-valence gigantic inorganic ring [Mo154O462H14(H2O)70]14- ({Mo154}-ring) and dimethyldioctadecylammonium (DODA) were combined to form novel molecular assemblies of an inorganic-organic hybrid molecular system as Langmuir-Blodgett (LB) and cast films. (DODA)20[Mo154O462H8(H2O)70] (2) was prepared by cation exchange and was characterized by a combination of thermogravimetry, IR, UV-vis-NIR, 1H NMR, and XRD measurements. The salt 2 was soluble in common organic solvents, and the chemical stability of {Mo154}-ring encapsulated by DODA cationic surfactants in CHCl3 was found to be higher than that of the "native" sodium salt of the {Mo154}-ring in H2O. Uniform spherical vesicle-like molecular assemblies of (DODA)20[Mo154O462H8(H2O)70] were observed in dilute THF, whose average diameter of 95 nm and a normalized variance of 5.7% were confirmed by a X-ray small-angle scattering. Deposition of 2 as a cast film showed circular domains with a typical diameter of approximately 100 nm, indicating possible similarities between solution and surface-deposited structures. The resulting LB films of salt 2 were transferred from an acidic buffer subphase with pH = 1.5 onto mica, giving a two-dimensional film surface with a unity transfer ratio. Further, the electronic absorption spectra of the LB multilayer were consistent with the classic type II mixed-valence MoV/MoVI electronic state well know for molybdenum blue {Mo154}-ring systems, and it appears that on the surface the plane of the {Mo154}-ring is approximately parallel to the substrate surface, as indicated by polarized electronic spectra, while the alkyl chains of DODA were relatively normal to the substrate surface. Therefore, the layer between the {Mo154}-rings and DODA cations was alternately stacked along the direction of film propagation. Finally, it was found that the surface morphology of the cast and LB films was determined by the molecular assembly of (DODA)20[Mo154O462H8(H2O)70] in

  20. Ozone uptake by citrus trees exposed to a range of ozone concentrations

    NASA Astrophysics Data System (ADS)

    Fares, Silvano; Park, Jeong-Hoo; Ormeno, Elena; Gentner, Drew R.; McKay, Megan; Loreto, Francesco; Karlik, John; Goldstein, Allen H.

    2010-09-01

    The Citrus genus includes a large number of species and varieties widely cultivated in the Central Valley of California and in many other countries having similar Mediterranean climates. In the summer, orchards in California experience high levels of tropospheric ozone, formed by reactions of volatile organic compounds (VOC) with oxides of nitrogen (NO x). Citrus trees may improve air quality in the orchard environment by taking up ozone through stomatal and non-stomatal mechanisms, but they may ultimately be detrimental to regional air quality by emitting biogenic VOC (BVOC) that oxidize to form ozone and secondary organic aerosol downwind of the site of emission. BVOC also play a key role in removing ozone through gas-phase chemical reactions in the intercellular spaces of the leaves and in ambient air outside the plants. Ozone is known to oxidize leaf tissues after entering stomata, resulting in decreased carbon assimilation and crop yield. To characterize ozone deposition and BVOC emissions for lemon ( Citrus limon), mandarin ( Citrus reticulata), and orange ( Citrus sinensis), we designed branch enclosures that allowed direct measurement of fluxes under different physiological conditions in a controlled greenhouse environment. Average ozone uptake was up to 11 nmol s -1 m -2 of leaf. At low concentrations of ozone (40 ppb), measured ozone deposition was higher than expected ozone deposition modeled on the basis of stomatal aperture and ozone concentration. Our results were in better agreement with modeled values when we included non-stomatal ozone loss by reaction with gas-phase BVOC emitted from the citrus plants. At high ozone concentrations (160 ppb), the measured ozone deposition was lower than modeled, and we speculate that this indicates ozone accumulation in the leaf mesophyll.

  1. The Antarctic Ozone Hole

    ERIC Educational Resources Information Center

    Jones, Anna E.

    2008-01-01

    Since the mid 1970s, the ozone layer over Antarctica has experienced massive destruction during every spring. In this article, we will consider the atmosphere, and what ozone and the ozone layer actually are. We explore the chemistry responsible for the ozone destruction, and learn about why conditions favour ozone destruction over Antarctica. For…

  2. Total ozone measurements made with the Brewer ozone spectrophotometer during STOIC 1989

    NASA Astrophysics Data System (ADS)

    Kerr, J. B.; McElroy, C. T.

    1995-05-01

    The Canadian Atmospheric Environment Service participated in the Stratospheric Ozone Intercomparison Campaign (STOIC) by operating a Brewer ozone spectrophotometer at the Table Mountain Observatory from July 19 to August 2, 1989. Frequent direct Sun measurements of total column ozone were made throughout most days during the 2 weeks of the intercomparison. Results of the Brewer instrument total ozone measurements are given. They show that there is a diurnal variation of total ozone with values increasing on average by 6.6±2.4 Dobson units between early morning and late afternoon. Comparing the total ozone measurements with ozone concentration measurements made at ground level suggests that the daytime increase is a result of a buildup of surface ozone during the day. The total ozone measurements made by the Brewer instrument during STOIC are compared with total ozone measurements made by the National Oceanic and Atmospheric Administration (NOAA) Dobson instrument, the NASA/Wallops electrochemical concentration cell ozonesondes and the total ozone mapping spectrometer satellite instrument.

  3. 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.

  4. 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)

  5. Ozone crisis

    SciTech Connect

    Roan, S.

    1989-01-01

    The author presents an account of the depletion of the atmosphere's ozone layer since the discovery of the phenomenon 15 years ago. The book recounts the flight to ban chlorofluorocarbons (CFC's) and describes the science, the people, and the politics involved, up to the March 1988 international treaty restricting CFC production. It surveys the media's coverage, describes the struggle for remedies, and offers a prognosis for the future.

  6. Diurnal variations of stratospheric ozone measured by ground-based microwave remote sensing at the Mauna Loa NDACC site: measurement validation and GEOSCCM model comparison

    NASA Astrophysics Data System (ADS)

    Parrish, A.; Boyd, I. S.; Nedoluha, G. E.; Bhartia, P. K.; Frith, S. M.; Kramarova, N. A.; Connor, B. J.; Bodeker, G. E.; Froidevaux, L.; Shiotani, M.; Sakazaki, T.

    2013-12-01

    There is presently renewed interest in diurnal variations of stratospheric and mesospheric ozone for the purpose of supporting homogenization of records of various ozone measurements that are limited by the technique employed to being made at certain times of day. We have made such measurements for 18 yr using a passive microwave remote sensing technique at the Mauna Loa Observatory in Hawaii, which is a primary station in the Network for Detection of Atmospheric Composition Change (NDACC). We have recently reprocessed these data with hourly time resolution to study diurnal variations. We inspected differences between pairs of the ozone spectra (e.g. day and night) from which the ozone profiles are derived to determine the extent to which they may be contaminated by diurnally varying systematic instrumental or measurement effects. These are small, and we have reduced them further by selecting data that meet certain criteria that we established. We have calculated differences between profiles measured at different times: morning-night, afternoon-night, and morning-afternoon and have intercompared these with like profiles derived from Aura-MLS, UARS-MLS, SMILES, and SBUV/2 measurements. Differences between averages of coincident profiles are typically <1.5% of typical nightime values over most of the covered altitude range with some exceptions. We calculated averages of ozone values for each hour from the Mauna Loa microwave data, and normalized these to the average for the first hour after midnight for comparison with corresponding values calculated with the Goddard Earth Observing System Chemistry Climate Model (GEOSCCM). We found that the measurements and model output mostly agree to better than 1.5% of the midnight value, with one noteworthy exception: the measured morning-night values are significantly (2-3%) higher than the modeled ones from 3.2 to 1.8 hPa (~39-43 km), and there is evidence that the measured values are increasing compared to the modeled values

  7. Mesospheric ozone measurements by SAGE II

    NASA Astrophysics Data System (ADS)

    Chu, D. A.; Cunnold, D. M.

    1994-04-01

    SAGE II observations of ozone at sunrise and sunset (solar zenith angle = 90 deg) at approximately the same tropical latitude and on the same day exhibit larger concentrations at sunrise than at sunset between 55 and 65 km. Because of the rapid conversion between atomic oxygen and ozone, the onion-peeling scheme used in SAGE II retrievals, which is based on an assumption of constant ozone, is invalid. A one-dimensional photochemical model is used to simulate the diurnal variation of ozone particularly within the solar zenith angle of 80 deg - 100 deg. This model indicates that the retrieved SAGE II sunrise and sunset ozone values are both overestimated. The Chapman reactions produce an adequate simulation of the ozone sunrise/sunset ratio only below 60 km, while above 60 km this ratio is highly affected by the odd oxygen loss due to odd hydrogen reactions, particularly OH. The SAGE II ozone measurements are in excellent agreement with model results to which an onion peeling procedure is applied. The SAGE II ozone observations provide information on the mesospheric chemistry not only through the ozone profile averages but also from the sunrise/sunset ratio.

  8. Mesospheric ozone measurements by SAGE II

    NASA Technical Reports Server (NTRS)

    Chu, D. A.; Cunnold, D. M.

    1994-01-01

    SAGE II observations of ozone at sunrise and sunset (solar zenith angle = 90 deg) at approximately the same tropical latitude and on the same day exhibit larger concentrations at sunrise than at sunset between 55 and 65 km. Because of the rapid conversion between atomic oxygen and ozone, the onion-peeling scheme used in SAGE II retrievals, which is based on an assumption of constant ozone, is invalid. A one-dimensional photochemical model is used to simulate the diurnal variation of ozone particularly within the solar zenith angle of 80 deg - 100 deg. This model indicates that the retrieved SAGE II sunrise and sunset ozone values are both overestimated. The Chapman reactions produce an adequate simulation of the ozone sunrise/sunset ratio only below 60 km, while above 60 km this ratio is highly affected by the odd oxygen loss due to odd hydrogen reactions, particularly OH. The SAGE II ozone measurements are in excellent agreement with model results to which an onion peeling procedure is applied. The SAGE II ozone observations provide information on the mesospheric chemistry not only through the ozone profile averages but also from the sunrise/sunset ratio.

  9. User's guide for SBUV/TOMS ozone derivative products

    NASA Technical Reports Server (NTRS)

    Fleig, A. J.; Wellemeyer, C.; Oslik, N.; Lee, D.; Miller, J.; Magatani, R.

    1984-01-01

    A series of products are available derived from the total-ozone and ozone vertical profile results for the Solar Backscattered Ultraviolet/Total-Ozone Mapping Spectrometer (SBUV/TOMS) Nimbus-7 operation. Products available are (1) orbital height-latitude cross sections of the SBUV profile data, (2) daily global total ozone contours in polar coordinates, (3) daily averages of total ozone in global 5x5 degree latitude-longitude grid, (4) daily, monthly and quarterly averages of total ozone and profile data in 10 degree latitude zones, (5) tabular presentation of zonal means, (6) daily global total ozone and profile contours in polar coordinates. The ""Derivative Products User's Guide'' describes each of these products in detail, including their derivation and presentation format. Information is provided on how to order the tapes and microfilm from the National Space Science Data Center.

  10. A Procedure for Inter-Comparing the Skill of Regional-Scale Air Quality Model Simulations of Daily Maximum 8-Hour Ozone Concentrations

    EPA Science Inventory

    An operational model evaluation procedure is described to quantitatively assess the relative skill among several regionalscale air quality models simulating various percentiles of the cumulative frequency distribution of observed daily maximum 8-h ozone concentrations. Bootstrap ...

  11. 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

  12. [Temporal and spatial distribution characteristics of ozone in Beijing].

    PubMed

    Wang, Zhan-shan; Li, Yun-ting; Chen, Tian; Zhang, Da-wei; Sun, Feng; Sun, Rui-wen; Dong, Xin; Sun, Nai-di; Pan, Li-bo

    2014-12-01

    Ozone concentrations obtained from 35 automatic air monitoring stations in Beijing were analyzed to investigate their temporal and spatial distribution characteristics. A process with high ozone concentration in summer was analyzed. The results showed that ozone maintained relatively high concentration from May to August while in other months, the ozone concentration was at a low level. Overall, the average concentrations of ozone in different stations in a descending order were comparison and regional station, suburban environment evaluation station, urban environmental assessment station and traffic pollution monitoring station. Ozone diurnal variation showed a single peak distribution, the peak of which appeared at 15:00 or 16:00. Ozone concentration showed obvious weekend effect, which meant ozone concentration in daytime of weekend was higher than that in weekday. Ozone concentration was lower in urban Beijing, higher in surrounding counties and the highest in northeast area with more vegetation. A high ozone concentration process occurred in Beijing on June 3, 2013. Under the effect of southwest wind in the afternoon, the concentration peaks of ozone in Yufa, Fengtaihuayuan, Olympic center and Huairou station occurred in order from south to north. Concentration peak of ozone in Huairou station occurred at 20:00 in the night. It could be concluded that significant ozone transmission characteristic was reflected in this process.

  13. [Characteristics of acid red 3R wastewater treatment by ozone microbubbles].

    PubMed

    Zhang, Jing; Du, Ya-Wei; Liu, Xiao-Jing; Zhou, Yu-Wen; Liu, Chun; Yang, Jing-Liang; Zhang, Lei

    2015-02-01

    The application of microbubble technology for ozonation wastewater treatment could enhance ozone mass transfer, improve ozonation performance and increase ozone utilization efficiency. The ozone microbubbles were used to treat synthetic acid red 3R wastewater in the present study, and compared to ozone conventional bubbles. The ozone mass transfer and ozonation characteristics of acid red 3R were investigated when ozone microbubbles and ozone conventional bubbles were applied. The results confirmed the enhanced ozone mass transfer using microbubbles. The ozone mass transfer coefficient using microbubbles was 3.6 times higher than that using conventional bubbles under the same conditions. Simultaneously, the ozone decomposition coefficient using microbubbles was 6.2 times higher than that using conventional bubbles, which would be favorable for *OH generation. The ozonation rate and mineralization efficiency of acid red 3R could be improved significantly using ozone microbubbles. A TOC removal efficiency of 78.0% was achieved using ozone microbubbles, which was about 2 times higher than that using ozone conventional bubbles. The ozone utilization efficiency using microbubbles was much higher that using conventional bubbles during ozonation treatment of acid red 3R. The average ozone utilization efficiencies were 97.8% and 69.3% when microbubbles and conventional bubbles were used, respectively. The oxidative ability of ozone microbubbles could be increased by enhancing *OH generation, and as a result, the oxidative reaction of degradation intermediates was accelerated by ozone microbubbles. Especially, the mineralization ability of small organic acid intermediates using ozone microbubbles was about 1.6 times higher than that using ozone conventional bubbles.

  14. On the observed response of ozone to NOx and VOC reactivity reductions in San Joaquin Valley California 1995-present

    NASA Astrophysics Data System (ADS)

    Pusede, S. E.; Cohen, R. C.

    2012-09-01

    We describe the effects of nitrogen oxide (NOx) and organic reactivity reductions on the frequency of high ozone days in California's San Joaquin Valley. We use sixteen years of observations of ozone, nitrogen oxides, and temperature at sites upwind, within, and downwind of three cities to assess the probability of exceeding the California 8-h average ozone standard of 70.4 ppb at each location. The comprehensive data records in the region and the steep decreases in emissions over the last decade are sufficient to constrain the relative import of NOx and organic reactivity reductions on the frequency of violations. We show that high ozone has a large component that is due to local production, as the probability of exceeding the state standard is lowest for each city at the upwind site, increases in the city center, is highest at downwind locations, and then decreases at the receptor city to the south. We see that reductions in organic reactivity have been very effective in the central and northern regions of the San Joaquin but less so in the southern portion of the Valley. We find evidence for two distinct categories of reactivity sources: one source that has decreased and dominates at moderate temperatures, and a second source that dominates at high temperatures, particularly in the southern San Joaquin, and has not changed over the last twelve years. We show that NOx reductions are already effective or are poised to become so in the southern and central Valley, where violations are most frequent, as conditions in these regions have or are transitioning to NOx-limited chemistry when temperatures are hottest and high ozone most probable.

  15. On the observed response of ozone to NOx and VOC reactivity reductions in San Joaquin Valley California 1995-present

    NASA Astrophysics Data System (ADS)

    Pusede, S. E.; Cohen, R. C.

    2012-04-01

    We present a statistical approach to describe the effects of nitrogen oxide (NOx) and organic reactivity reductions on the frequency of high ozone days. We use sixteen years of observations of ozone, nitrogen oxides, and temperature at sites upwind, within, and downwind of three cities in California's San Joaquin Valley to assess the probability of exceeding of the California 8-h average ozone standard of 70.4 ppb at each location. We demonstrate that the comprehensive data records in the region and the steep decreases in emissions over the last decade are sufficient to constrain the relative import of NOx and organic reactivity reductions on the frequency of violations. We show that high ozone has a large component that is due to local production, as the probability of exceeding the state standard is lowest for each city at the upwind site, increases across the city center, is highest at downwind locations, and then decreases at the receptor city to the south. We see that reductions in organic reactivity have been very effective in the central and northern regions of the San Joaquin but not in the southern portion of the Valley. We find evidence for two distinct categories of reactivity sources: one source that has decreased and dominates at moderate temperatures, and a second source that dominates at high temperatures in the southern San Joaquin, which has not changed over the last twelve years. We show that NOx reductions are already effective or are poised to become so in the southern and central Valley, where violations are most frequent, as conditions in these regions have or are transitioning to NOx-limited chemistry when temperatures are hottest and high ozone most probable.

  16. Record low global ozone in 1992

    NASA Astrophysics Data System (ADS)

    Gleason, J. F.; Bhartia, P. K.; Herman, J. R.; McPeters, R.; Newman, P.; Stolarski, R. S.; Flynn, L.; Labow, G.; Larko, D.; Seftor, C.

    1993-04-01

    The 1992 global average total ozone, measured by the Total Ozone Mapping Spectrometer (TOMS) on the Nimbus-7 satellite, was 2 to 3 percent lower than any earlier year observed by TOMS (1979 to 1991). Ozone amounts were low in a wide range of latitudes in both the Northern and Southern Hemispheres, and the largest decreases were in the regions from 10 to 20 deg S and 10 to 60 deg N. Global ozone in 1992 is at least 1.5 percent lower than would be predicted by a statistical model that includes a linear trend and accounts for solar cycle variation and the quasi-biennial oscillation. These results are confirmed by comparisons with data from other ozone monitoring instruments: the SBUV/2 instrument on the NOAA-11 satellite, the TOMS instrument on the Russian Meteor-3 satellite, the World Standard Dobson Instrument 83, and a collection of 22 ground-based Dobson instruments.

  17. The prediction of recommended energy expenditure for an 8 h work-day using an air-purifying respirator.

    PubMed

    Sulotto, F; Romano, C; Dori, S; Piolatto, G; Chiesa, A; Ciacco, C; Scansetti, G

    1993-12-01

    Thirty railway workers executed maximal, or near maximal, stress tests with and without the use of a half mask air-purifying respirator (Spasciani 85 A1 P1) fitted with two combined filters for simultaneous protection from organic vapours and particulate matter. The pressure-flow characteristics of inspiratory and expiratory resistance at airflows in the range 0-90 l.min-1 were established by a continuous flow method on one test mask. Significant differences were found by paired t-test between the two exercises (with and without use of mask), showing reduced values with use of the mask, for breath frequency, ventilation rate, oxygen uptake, carbon dioxide production, maximal oxygen uptake, percentage of maximal voluntary ventilation used at the maximal exercise ventilation. No significant differences were found for tidal volume, respiratory quotient, heart rate, systolic blood pressure, oxygen uptake at anaerobic threshold, and duration of exercise. The predicted energy expenditure recommended for an 8 h work shift, corresponding to 40% of maximal oxygen uptake, is found to be reduced working with respirator and is significantly different from that observed during stress test without mask. The average ventilation rate at this workload is below 25 l.min-1, with predicted inspiratory mouth pressure equal to, or less than, 20 mm H2O. This maximal inspiratory mouth pressure is proposed as a safety limit for prolonged work using a respirator, with a recommended energy expenditure close to 40% of maximal oxygen uptake. PMID:8287854

  18. Influence of the ozone profile above Madrid (Spain) on Brewer estimation of ozone air mass factor

    NASA Astrophysics Data System (ADS)

    Antón, M.; López, M.; Costa, M. J.; Serrano, A.; Bortoli, D.; Bañón, M.; Vilaplana, J. M.; Silva, A. M.

    2009-08-01

    The methodology used by Brewer spectroradiometers to estimate the ozone column is based on differential absorption spectroscopy. This methodology employs the ozone air mass factor (AMF) to derive the total ozone column from the slant path ozone amount. For the calculating the ozone AMF, the Brewer algorithm assumes that the ozone layer is located at a fixed height of 22 km. However, for a real specific site the ozone presents a certain profile, which varies spatially and temporally depending on the latitude, altitude and dynamical conditions of the atmosphere above the site of measurements. In this sense, this work address the reliability of the mentioned assumption and analyses the influence of the ozone profiles measured above Madrid (Spain) in the ozone AMF calculations. The approximated ozone AMF used by the Brewer algorithm is compared with simulations obtained using the libRadtran radiative transfer model code. The results show an excellent agreement between the simulated and the approximated AMF values for solar zenith angle lower than 75°. In addition, the relative differences remain lower than 2% at 85°. These good results are mainly due to the fact that the altitude of the ozone layer assumed constant by the Brewer algorithm for all latitudes notably can be considered representative of the real profile of ozone above Madrid (average value of 21.7±1.8 km). The operational ozone AMF calculations for Brewer instruments are limited, in general, to SZA below 80°. Extending the usable SZA range is especially relevant for Brewer instruments located at high mid-latitudes.

  19. Decadal evolution of the Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Jiang, Y.; Yung, Y. L.; Zurek, R. W.

    1996-01-01

    Ozone column amounts obtained by the total ozone mapping spectrometer (TOMS) in the southern polar region are analyzed during late austral winter and spring (days 240-300) for 1980-1991 using area-mapping techniques and area-weighted vortex averages. The vortex here is defined using the -50 PVU (1 PVU = 1.0 x 10(-6) K kg-1 m2 s-1) contour on the 500 K isentropic surface. The principal results are: (1) there is a distinct change after 1985 in the vortex-averaged column ozone depletion rate during September and October, the period of maximum ozone loss, and (2) the vortex-averaged column ozone in late August (day 240) has dropped by 70 Dobson units (DU) in a decade due to the loss in the dark and the dilution effect. The mean ozone depletion rate in the vortex between day 240 and the day of minimum vortex-averaged ozone is about 1 DU d-1 at the beginning of the decade, increasing to about 1.8 DU d-1 by 1985, and then apparently saturating thereafter. The vortex-average column ozone during September and October has declined at the rate of 11.3 DU yr-1 (3.8%) from 1980 to 1987 (90 DU over 8 years) and at a smaller rate of 2 DU yr-1 (0.9%) from 1987 to 1991 (10 DU over 5 years, excluding the anomalous year 1988). We interpret the year-to-year trend in the ozone depletion rate during the earlier part of the decade as due to the rise of anthropogenic chlorine in the atmosphere. The slower trend at the end of the decade indicates saturation of ozone depletion in the vortex interior, in that chlorine amounts in the mid-1980s were already sufficiently high to deplete most of the ozone in air within the isolated regions of the lower-stratospheric polar vortex. In subsequent years, increases in stratospheric chlorine may have enhanced wintertime chemical loss of ozone in the south polar vortex even before major losses during the Antarctic spring.

  20. Ozone variations through vehicle emissions reductions based on air quality monitoring data in Taipei City, Taiwan, from 1994 to 2003

    NASA Astrophysics Data System (ADS)

    Chang, Shuenn-Chin; Lee, Chung-Te

    The ozone (O 3) ambient air quality is evaluated using two indices in Taiwan: the daily maximum O 3 concentration (O 3, max ) greater than 120 ppb and the daily 8-h O 3 moving average (O 3, 8 h ) greater than 60 ppb. Results of air quality monitoring data from 1994 to 2003 in Taipei City indicate that the 99th percentile O 3, max was reduced, but those below the 90th percentile O 3, max obviously increased and days with O 3, 8 h greater than 60 ppb were doubled after the reduction of O 3 precursor emissions. Because of Taipei's unique vehicle emissions pattern in having more motorcycles than cars, Sunday, as compared to weekdays, has more reductions of non-methane hydrocarbons (NMHCs) than NO X. This results in Sunday O 3, max being lower than weekday O 3, max average for those days with O 3, max exceeding 80 ppb. On the contrary, if O 3, max is lower than 60 ppb, Sunday O 3, max is relatively higher than weekday O 3, max average, due to the reduced NO titration effect. In addition, our evaluations of O 3 levels with respect to the ambient air quality standards show that the number of Sundays with O 3, max greater than 120 ppb is fewer than the number average of weekdays with O 3, max exceeding 120 ppb for every month. Concerning O 3, 8 h , only in June, July, and August, when the meteorological conditions favor O 3 production, does the reduction of Sunday vehicle exhaust reduce the number of days with O 3,8h greater than 60 ppb. However, in September and October, the reduction of Sunday vehicle exhaust will increase the number of days. The results presented in this paper indicate that the O 3 pollution in Taipei City is VOC-limited. Thus, for a greater reduction in NMHCs, like the Sunday vehicle reduction in Taipei City, the upper percentile O 3, max is reduced more and those below the moderately high percentile O 3, max are increased less.

  1. The 14.8-h orbital period of GX339-4

    NASA Technical Reports Server (NTRS)

    Callanan, P. J.; Charles, P. A.; Honey, W. B.; Thorstensen, J. R.

    1992-01-01

    We present the results of photometric observations of the black hole candidate GX339-4, obtained while the system was in an 'off' state. We show that a 14.8-h modulation was present, and provide evidence for a similar periodicity in the 'high' state from a reanalysis of previously published photometry and spectroscopy. The presence of the same period in both states implies that it is likely to be the orbital period of the system. The spectroscopy analysis provides evidence for an apparent change in the systemic velocity of the system. The amplitude of the observed radial velocity variations, however, permits only crude limits to be placed on the mass of the compact object. Only absorption-line spectroscopy of the secondary in the 'off' state will provide a convincing mass determination.

  2. Comparative morphometric study of the australopithecine vertebral series Stw-H8/H41.

    PubMed

    Sanders, W J

    1998-03-01

    Lower spinal structure correlates well with positional behavior among mammals. Nonetheless, the functional morphology of the axial post-crania of australopithecines has received less attention than their appendicular skeletons. This paper presents a detailed description and comparative morphometric analysis of the australopithecine thoracolumbar vertebral series Stw-H8/H41, and examines spinal mechanics in early hominids. Stw-H8/H41 is an important specimen, as the australopithecine vertebral sample is small, and vertebral series are more useful than isolated elements for the interpretation of spinal function. Results of the study support the interpretation that australopithecine species are highly sexually dimorphic. The study also reveals a considerable amount of morphometric variation other than size among australopithecine vertebrae, though the sample is too small and incomplete to ascertain whether this indicates significant interspecific differences in spinal function. Most importantly, structural and metric observations confirm that the morphology of the lower spine in australopithecines has no modern analogue in its entirety. Aspects of zygapophyseal structure, numerical composition of the lumbar region, and centrum wedging suggest that the australopithecine vertebral column was adapted to human-like intrinsic lumbar lordosis and stable balance of the trunk over the pelvis in sustained bipedal locomotion. However, relative centrum size in australopithecines indicates that either they had a different mechanism for channeling vertical forces through the vertebral column than humans, or differed behaviorally from humans in ways that produced smaller increments of compression across their centra. These findings have important implications for hypotheses of australopithecine positional behavior, and demonstrate that larger samples and more complete vertebral series are needed to improve our understanding of australopithecine spinal function. PMID:9547457

  3. Comparative morphometric study of the australopithecine vertebral series Stw-H8/H41.

    PubMed

    Sanders, W J

    1998-03-01

    Lower spinal structure correlates well with positional behavior among mammals. Nonetheless, the functional morphology of the axial post-crania of australopithecines has received less attention than their appendicular skeletons. This paper presents a detailed description and comparative morphometric analysis of the australopithecine thoracolumbar vertebral series Stw-H8/H41, and examines spinal mechanics in early hominids. Stw-H8/H41 is an important specimen, as the australopithecine vertebral sample is small, and vertebral series are more useful than isolated elements for the interpretation of spinal function. Results of the study support the interpretation that australopithecine species are highly sexually dimorphic. The study also reveals a considerable amount of morphometric variation other than size among australopithecine vertebrae, though the sample is too small and incomplete to ascertain whether this indicates significant interspecific differences in spinal function. Most importantly, structural and metric observations confirm that the morphology of the lower spine in australopithecines has no modern analogue in its entirety. Aspects of zygapophyseal structure, numerical composition of the lumbar region, and centrum wedging suggest that the australopithecine vertebral column was adapted to human-like intrinsic lumbar lordosis and stable balance of the trunk over the pelvis in sustained bipedal locomotion. However, relative centrum size in australopithecines indicates that either they had a different mechanism for channeling vertical forces through the vertebral column than humans, or differed behaviorally from humans in ways that produced smaller increments of compression across their centra. These findings have important implications for hypotheses of australopithecine positional behavior, and demonstrate that larger samples and more complete vertebral series are needed to improve our understanding of australopithecine spinal function.

  4. Ozone Hole Over Antarctica

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These images from the Total Ozone Mapping Spectrometer (TOMS) show the progressive depletion of ozone over Antarctica from 1979 to 1999. This 'ozone hole' has extended to cover an area as large as 10.5 million square miles in September 1998. The previous record of 10.0 million square miles was set in 1996. The Antarctic ozone hole develops each year between late August and early October. Regions with higher levels of ozone are shown in red. NASA and NOAA instruments have been measuring Antarctic ozone levels since the early 1970s. Large regions of depleted ozone began to develop over Antarctica in the early 1980s. Ozone holes of substantial size and depth are likely to continue to form during the next few years, scientists hope to see a reduction in ozone loss as levels of ozone-destroying CFCs (chlorofluorocarbons) are gradually reduced. Credit: Images by Greg Shirah, NASA Goddard Space Flight Center Scientific Visualization Studio

  5. Ozone profiles above Palmer Station, Antarctica

    NASA Technical Reports Server (NTRS)

    Torres, Arnold L.; Brothers, George

    1988-01-01

    NASA's Goddard Space Flight Center/Wallops Flight Facility conducted a series of 52 balloon-borne measurements of vertical ozone profiles over the National Science Foundation (NSF) research facility at Palmer Station, Antarctica (64 deg 46 S, 64 deg 3 W) between August 9 and October 24, 1987. High resolution measurements were made from ground level to an average of 10 mb. While much variation was seen in the profile amounts of ozone, it is clear that a progressive depletion of ozone occurred during the measurement period, with maximum depletion taking place in the 17 to 19 km altitude region. Ozone partial pressures dropped by about 95 percent in this region. Shown here are plotted time dependences of ozone amounts observed at 17 km and at arbitrarily selected altitudes below (13 km) and above (24 km) the region of maximum depletion. Ozone partial pressure at 17 km is about 150nb in early August, and has decreased to less than 10nb in the minimums in October. The loss rate is of the order of 1.5 percent/day. In summary, a progressive depletion in stratospheric ozone over Palmer Station was observed from August to October, 1987. Maximum depletion occurred in the 17 to 19 km range, and amounted to 95 percent. Total ozone overburden decreased by up to 50 percent during the same period.

  6. Recovery of the Antarctic Ozone Hole

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Kawa, S. Randolph; Montzka, Steve; Schauffler, Sue; Stolarski, Richard S.; Douglass, Anne R.; Pawson, Steven; Nielsen, J. Eric

    2006-01-01

    The Antarctic ozone hole develops each year and culminates by early Spring. Antarctic ozone values have been monitored since 1979 using satellite observations from the TOMS and OMI instruments. The severity of the hole has been assessed using the minimum total ozone value from the October monthly mean (depth of the hole), the average size during the September-October period, and the ozone mass deficit. Ozone is mainly destroyed by halogen catalytic cycles, and these losses are modulated by temperature variations in the collar of the polar lower stratospheric vortex. In this presentation, we show the relationships of halogens and temperature to both the size and depth of the hole. 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. We use two methods to estimate ozone hole recovery. First, we use projections of halogen levels combined with age-of-air estimates in a parametric model. Second, we use a coupled chemistry climate model to assess recovery. 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. Furthermore, full recovery to 1980 levels will not occur until approximately 2068. We will also show some error estimates of these dates and the impact of climate change on the recovery.

  7. When Will the Antarctic Ozone Hole Recover?

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.

    2006-01-01

    The Antarctic ozone hole develops each year and culminates by early spring (late September - early October). Antarctic ozone values have been monitored since 1979 using satellite observations from the TOMS instrument. The severity of the hole has been assessed from TOMS 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. Ozone is mainly destroyed by halogen (chlorine and bromine) catalytic cycles, and these losses are modulated by temperature variations in the collar of the polar lower stratospheric vortex. In this talk, I will show the relationships of halogens and temperature to both the size and depth of the hole. 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. The ozone hole will begin to show first signs of recovery in about 2023, and the hole will fully recover to pre-1980 levels in approximately 2070. This 2070 recovery is 20 years later than recent projections. I will also discuss current assessments of mid-latitude ozone recovery.

  8. The Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Molina, Mario J.

    1988-01-01

    Observations of Antarctic ozone levels and the discovery of a hole in the Antarctic region are examined. The effects of chlorofluorocarbons (CFCs) on the level of stratospheric ozone are analyzed. Three cycles explaining the cause of ozone depletion in the poles are proposed. A comparison of field data and proposed depletion cycles reveals that the chemical origin of the ozone hole is due to CFCs. The potential global effects of the Antarctic ozone hole are discussed.

  9. 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.

  10. Spatial distribution of tropospheric ozone in western Washington, USA.

    PubMed

    Cooper, S M; Peterson, D L

    2000-03-01

    We quantified the distribution of tropospheric ozone in topographically complex western Washington state, USA (total area approximately 6000 km(2)), 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=55-67 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. PMID:15092980

  11. Ozone depletion at northern and southern latitudes derived from January 1979 to December 1991 Total Ozone Mapping Spectrometer Data

    SciTech Connect

    Herman, J.R.; McPeters, R.; Larko, D.

    1993-07-20

    Long-term ozone depletion rates (percentage change) have been computed from 13 years of Nimbus 8/Total Ozone Mapping Spectrometer (TOMS) data as a function of latitude, longitude, and month for the period January 1, 1979, to December 31, 1991. In both hemispheres the amount of ozone has decreased at latitudes above 30{degrees} by amounts that are larger than predicted by homogeneous chemistry models for the 13-year time period. The largest rates of ozone decrease occur in the southern hemisphere during winter and spring, with partial recovery during the summer and autumn. Outside of the Antarctic ozone hole region, the 12-year ozone depletion rates reach 8-10% per decade during the winter and spring at 55{degrees}S. Ozone depletion rates in excess of 7% per decade occur over populated regions in the southern hemisphere poleward of 45{degrees}S for 7 months of the year. Similar rates of decrease occur during northern winter and spring over large populated regions. The enhanced zonal average ozone depletion rates at northern mid-latitudes (40-50{degrees}N) during January, February, and March, that correspond to five geographically localized regions of high ozone depletion rates, are probably associated with long-term dynamical or temperature changes. Only the equatorial band between {+-}20{degrees} shows little or no long-term ozone change since January 1979. Ozone time series data have been examined for effect of volcanic eruptions on stratospheric ozone observed by TOMS, with only the Mount Pinatubo stratospheric aerosol injection affecting ozone amounts for a few months after the eruption in June 1991. Errors caused by the short-term presence of stratospheric aerosols in the TOMS zonally averaged ozone data are less than 1% before correction, and have no significant effect on ozone trend determination. 49 refs., 6 figs., 2 tabs.

  12. [Ozone decline and UV increase].

    PubMed

    Winkler, P; Trepte, S

    2004-02-01

    The following results have been obtained from long-term observations on the ozone layer and UV at the Meteorological Observatory Hohenpeigenberg:The seasonally varying decline of the ozone layer determines the maximum exposure to UV. Since ozone decline shows the highest rates in the spring months the UV exposure has most strongly increased in this time of the year. This is especially important because in spring the human skin is not adapted to UV exposure. Weather changes from day to day can induce rapid ozone reductions in spring about -30% which in turn is followed by an increase in UV of about 40%. Clouds, especially the transparent cirrus clouds (high clouds consisting of ice particles) have increased in frequency during spring and fall while a decrease is observed in summer. This change in cloudiness reduces the daily UV dose in spring and fall while it is enhanced in summer. With increasing height above sea level UV rises by roughly 10% per 1000 m (rule of thumb). Snow reflects the UV-radiation by up to 80% enhancing the UV-doses at relevant conditions. Strong volcano eruptions destroy ozone in the stratosphere additionally during 1-2 years after the eruption. Therafter the ozone layer recovers. In April 1993, after the eruption of Mt. Pinatubo (1991), the UV burden was still 40% higher than average. Miniholes and streamers can appear unexpected on a short-time scale and cross over Central Europe within 1-2 days, thus enhancing UV irradiation. The human skin reacts to UV exposure depending on the type of skin. The campaign "Sonne(n) mit Verstand" of the Bavarian Ministries for Environment, for Health and for Education informs about the danger of UV radiation (see www.sonne-mit-ver-stand.de). The German Weather Service informs the public on present developments of the ozone layer and relevant topics byits ozone bulletin, which is also available via internet under (www.dwd.de/deFundE/Observator/MOHp/hp2/ozon/bulletin.htm).

  13. [Ozone decline and UV increase].

    PubMed

    Winkler, P; Trepte, S

    2004-02-01

    The following results have been obtained from long-term observations on the ozone layer and UV at the Meteorological Observatory Hohenpeigenberg:The seasonally varying decline of the ozone layer determines the maximum exposure to UV. Since ozone decline shows the highest rates in the spring months the UV exposure has most strongly increased in this time of the year. This is especially important because in spring the human skin is not adapted to UV exposure. Weather changes from day to day can induce rapid ozone reductions in spring about -30% which in turn is followed by an increase in UV of about 40%. Clouds, especially the transparent cirrus clouds (high clouds consisting of ice particles) have increased in frequency during spring and fall while a decrease is observed in summer. This change in cloudiness reduces the daily UV dose in spring and fall while it is enhanced in summer. With increasing height above sea level UV rises by roughly 10% per 1000 m (rule of thumb). Snow reflects the UV-radiation by up to 80% enhancing the UV-doses at relevant conditions. Strong volcano eruptions destroy ozone in the stratosphere additionally during 1-2 years after the eruption. Therafter the ozone layer recovers. In April 1993, after the eruption of Mt. Pinatubo (1991), the UV burden was still 40% higher than average. Miniholes and streamers can appear unexpected on a short-time scale and cross over Central Europe within 1-2 days, thus enhancing UV irradiation. The human skin reacts to UV exposure depending on the type of skin. The campaign "Sonne(n) mit Verstand" of the Bavarian Ministries for Environment, for Health and for Education informs about the danger of UV radiation (see www.sonne-mit-ver-stand.de). The German Weather Service informs the public on present developments of the ozone layer and relevant topics byits ozone bulletin, which is also available via internet under (www.dwd.de/deFundE/Observator/MOHp/hp2/ozon/bulletin.htm). PMID:14770335

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

    SciTech Connect

    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 {+-} 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.

  15. Smoke in the City: How Often and Where Does Smoke Impact Summertime Ozone in the United States?

    PubMed

    Brey, Steven J; Fischer, Emily V

    2016-02-01

    We investigate the influence of smoke on ozone (O3) abundances over the contiguous United States. Using colocated observations of particulate matter and the National Weather Service Hazard Mapping System smoke data, we identify summertime days between 2005 and 2014 that Environmental Protection Agency Air Quality System O3 monitors are influenced by smoke. We compare O3 mixing ratio distributions for smoke-free and smoke-impacted days for each monitor, while controlling for temperature. This analysis shows that (i) the mean O3 abundance measured on smoke-impacted days is higher than on smoke-free days, and (ii) the magnitude of the effect varies by location with a range of 3 to 36 ppbv. For each site, we present the percentage of days when the 8-h average O3 mixing ratio (MDA8) exceeds 75 ppbv and smoke is present. Smoke-impacted O3 mixing ratios are most elevated in locations with the highest emissions of nitrogen oxides. The Northeast corridor, Dallas, Houston, Atlanta, Birmingham, and Kansas City stand out as having smoke present 10-20% of the days when 8-h average O3 mixing ratios exceed 75 ppbv. Most U.S. cities maintain a similar proportion of smoke-impacted exceedance days when they are held against the new MDA8 limit of 70 ppbv.

  16. Smoke in the City: How Often and Where Does Smoke Impact Summertime Ozone in the United States?

    PubMed

    Brey, Steven J; Fischer, Emily V

    2016-02-01

    We investigate the influence of smoke on ozone (O3) abundances over the contiguous United States. Using colocated observations of particulate matter and the National Weather Service Hazard Mapping System smoke data, we identify summertime days between 2005 and 2014 that Environmental Protection Agency Air Quality System O3 monitors are influenced by smoke. We compare O3 mixing ratio distributions for smoke-free and smoke-impacted days for each monitor, while controlling for temperature. This analysis shows that (i) the mean O3 abundance measured on smoke-impacted days is higher than on smoke-free days, and (ii) the magnitude of the effect varies by location with a range of 3 to 36 ppbv. For each site, we present the percentage of days when the 8-h average O3 mixing ratio (MDA8) exceeds 75 ppbv and smoke is present. Smoke-impacted O3 mixing ratios are most elevated in locations with the highest emissions of nitrogen oxides. The Northeast corridor, Dallas, Houston, Atlanta, Birmingham, and Kansas City stand out as having smoke present 10-20% of the days when 8-h average O3 mixing ratios exceed 75 ppbv. Most U.S. cities maintain a similar proportion of smoke-impacted exceedance days when they are held against the new MDA8 limit of 70 ppbv. PMID:26720416

  17. Bonding in Complexes of Bis(pentalene)dititanium, Ti2(C8H6)2

    PubMed Central

    2015-01-01

    Bonding in the bis(pentalene)dititanium “double-sandwich” species Ti2Pn2 (Pn = C8H6) and its interaction with other fragments have been investigated by density functional calculations and fragment analysis. Ti2Pn2 with C2v symmetry has two metal–metal bonds and a low-lying metal-based empty orbital, all three frontier orbitals having a1 symmetry. The latter may be regarded as being derived by symmetric combinations of the classic three frontier orbitals of two bent bis(cyclopentadienyl) metal fragments. Electrochemical studies on Ti2Pn†2 (Pn† = 1,4-{SiiPr3}2C8H4) revealed a one-electron oxidation, and the formally mixed-valence Ti(II)–Ti(III) cationic complex [Ti2Pn†2][B(C6F5)4] has been structurally characterized. Theory indicates an S = 1/2 ground-state electronic configuration for the latter, which was confirmed by EPR spectroscopy and SQUID magnetometry. Carbon dioxide binds symmetrically to Ti2Pn2, preserving the C2v symmetry, as does carbon disulfide. The dominant interaction in Ti2Pn2CO2 is σ donation into the LUMO of bent CO2, and donation from the O atoms to Ti2Pn2 is minimal, whereas in Ti2Pn2CS2 there is significant interaction with the S atoms. The bridging O atom in the mono(oxo) species Ti2Pn2O, however, employs all three O 2p orbitals in binding and competes strongly with Pn, leading to weaker binding of the carbocyclic ligand, and the sulfur analogue Ti2Pn2S behaves similarly. Ti2Pn2 is also capable of binding one, two, or three molecules of carbon monoxide. The bonding demands of a single CO molecule are incompatible with symmetric binding, and an asymmetric structure is found. The dicarbonyl adduct Ti2Pn2(CO)2 has Cs symmetry with the Ti2Pn2 unit acting as two MCp2 fragments. Synthetic studies showed that in the presence of excess CO the tricarbonyl complex Ti2Pn†2(CO)3 is formed, which optimizes to an asymmetric structure with one semibridging and two terminal CO ligands. Low-temperature 13C NMR spectroscopy revealed a rapid

  18. Meteorology-induced variations in the spatial behavior of summer ozone pollution in Central California

    SciTech Connect

    Jin, Ling; Harley, Robert A.; Brown, Nancy J.

    2010-06-23

    Cluster analysis was applied to daily 8 h ozone maxima modeled for a summer season to characterize meteorology-induced variations in the spatial distribution of ozone. Principal component analysis is employed to form a reduced dimension set to describe and interpret ozone spatial patterns. The first three principal components (PCs) capture {approx}85% of total variance, with PC1 describing a general spatial trend, and PC2 and PC3 each describing a spatial contrast. Six clusters were identified for California's San Joaquin Valley (SJV) with two low, three moderate, and one high-ozone cluster. The moderate ozone clusters are distinguished by elevated ozone levels in different parts of the valley: northern, western, and eastern, respectively. The SJV ozone clusters have stronger coupling with the San Francisco Bay area (SFB) than with the Sacramento Valley (SV). Variations in ozone spatial distributions induced by anthropogenic emission changes are small relative to the overall variations in ozone amomalies observed for the whole summer. Ozone regimes identified here are mostly determined by the direct and indirect meteorological effects. Existing measurement sites are sufficiently representative to capture ozone spatial patterns in the SFB and SV, but the western side of the SJV is under-sampled.

  19. Variability and sources of surface ozone at rural sites in Nevada, USA: Results from two years of the Nevada Rural Ozone Initiative.

    PubMed

    Fine, Rebekka; Miller, Matthieu B; Burley, Joel; Jaffe, Daniel A; Pierce, R Bradley; Lin, Meiyun; Gustin, Mae Sexauer

    2015-10-15

    Ozone (O3) has been measured at Great Basin National Park (GBNP) since September 1993. GBNP is located in a remote, rural area of eastern Nevada. Data indicate that GBNP will not comply with a more stringent National Ambient Air Quality Standard (NAAQS) for O3, which is based upon the 3-year average of the annual 4th highest Maximum Daily 8-h Average (MDA8) concentration. Trend analyses for GBNP data collected from 1993 to 2013 indicate that MDA8 O3 increased significantly for November to February, and May. The greatest increase was for May at 0.38, 0.35, and 0.46 ppb yr(-1) for the 95th, 50th, and 5th percentiles of MDA8 O3 values, respectively. With the exception of GBNP, continuous O3 monitoring in Nevada has been limited to the greater metropolitan areas. Due to the limited spatial detail of O3 measurements in rural Nevada, a network of rural monitoring sites was established beginning in July 2011. For a period ranging from July 2011 to June 2013, maximum MDA8 O3 at 6 sites occurred in the spring and summer, and ranged from 68 to 80ppb. Our analyses indicate that GBNP, in particular, is ideally positioned to intercept air containing elevated O3 derived from regional and global sources. For the 2 year period considered here, MDA8 O3 at GBNP was an average of 3.1 to 12.6 ppb higher than at other rural Nevada sites. Measured MDA8 O3 at GBNP exceeded the current regulatory threshold of 75 ppb on 7 occasions. Analyses of synoptic conditions, model tracers, and air mass back-trajectories on these days indicate that stratospheric intrusions, interstate pollution transport, wildfires, and Asian pollution contributed to elevated O3 observed at GBNP. We suggest that regional and global sources of ozone may pose challenges to achieving a more stringent O3 NAAQS in rural Nevada.

  20. Surface ozone concentrations in Agra: links with the prevailing meteorological parameters

    NASA Astrophysics Data System (ADS)

    Singla, Vyoma; Pachauri, Tripti; Satsangi, Aparna; Kumari, K. Maharaj; Lakhani, Anita

    2012-12-01

    Measurements of surface ozone (O3), nitric oxide (NO), nitrogen dioxide (NO2), oxides of nitrogen (NOx=NO+NO2) and meteorological parameters have been made at Agra (North Central India, 27°10'N, 78°05'E) in post monsoon and winter season. The diurnal variation in O3 concentration shows daytime in situ photochemical production with diurnal maximum in noon hours ranging from 51 to 54 ppb in post monsoon and from 76 to 82 ppb in winter, while minimum (16-24 ppb) during nighttime and early morning hours. Average 8-h O3 concentration varied from 12.4 to 83.9 ppb. The relationship between meteorological parameters (solar radiation intensity, temperature, relative humidity, wind speed and wind direction) and surface O3 variability was studied using principal component analysis (PCA), multiple linear regression (MLR) and correlation analysis (CA). PCA and MLR of daily mean O3 concentrations on meteorological parameters explain up to 80 % of day to day ozone variability. Correlation with meteorology is strongly emphasized on days having strong solar radiation intensity and longer sunshine time.

  1. Ozone depletion at northern and southern latitudes derived from January 1979 to December 1991 Total Ozone Mapping Spectrometer data

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Mcpeters, R.; Larko, D.

    1993-01-01

    An extended version of the Nimbus 7/TOMS ozone data set from the period January 1, 1979 to December 31, 1991 is presented. It is shown that the ozone-trend data indicate that regions of enhanced ozone depletion rates have formed at middle and high latitudes during recent years. The seasonal dependence and geographical extent of the enhanced ozone-depletion rates for the Northern and Southern hemispheres are examined. The variability of the long-term ozone trend determination is discussed via consideration of the differences among 11-, 12-, and 13-yr trend calculations. The effects of the Mount Pinatubo eruption and other volcanic eruptions on the TOMS equatorial zonal average ozone measurements, and its influence on long-term trend determinations are discussed. On the basis of a determination of the aerosol phase function using TOMS data, the effect of stratospheric aerosols on determination of ozone amounts from TOMS are shown to be less than 1 percent.

  2. Interfacial properties in Langmuir monolayers and LB films of DPPC with partially fluorinated alcohol (F8H7OH).

    PubMed

    Nakahara, Hiromichi; Hirano, Chikayo; Fujita, Ichiro; Shibata, Osamu

    2013-01-01

    Two-component interactions between (perfluorooctyl) heptanol (F8H7OH) and dipalmitoylphosphatidylcholine (DPPC), which is a major component of pulmonary surfactants in mammals, were systematically elucidated using Langmuir monolayers and Langmuir-Blodgett (LB) films of the compounds. The interactions such as the miscibility of the compounds and their phase behavior were examined from thermodynamic and morphological perspectives. The surface pressure (π)-molecular area (A) and surface potential (ΔV)-A isotherms of the binary monolayers containing F8H7OH in different mole fractions (XF8H7OH) were measured simultaneously. The excess Gibbs free energy of mixing of the two components was calculated from the π-A isotherms. The resulting isotherm data were employed to construct a two-dimensional (2D) phase diagram of the system. The phase diagram revealed that the transition pressure as well as the monolayer collapse pressure change with changes in XF8H7OH. These thermodynamic analyses suggested that the miscibility of the two components and the solidification of DPPC monolayers can be induced by the addition of F8H7OH. The phase behavior upon monolayer compression was observed morphologically in situ using Brewster angle microscopy (BAM) and fluorescence microscopy (FM), as well as ex situ using atomic force microscopy (AFM). Interestingly, the AFM-based analysis revealed the formation of monodispersed 2D micelles consisting of F8H7OH at low surface pressures.

  3. Options to accelerate ozone recovery:ozone and climate benefits

    NASA Astrophysics Data System (ADS)

    Daniel, J. S.; Fleming, E. L.; Portmann, R. W.; Velders, G. J. M.; Jackman, C. H.; Ravishankara, A. R.

    2010-04-01

    Hypothetical reductions in future emissions of ozone-depleting substances (ODSs), including N2O, are evaluated in terms of effects on equivalent effective stratospheric chlorine (EESC), globally-averaged total column ozone, and radiative forcing through 2100. Due to the established success of the Montreal Protocol, these actions can have only a fraction of the impact that regulations already in force have had. If all anthropogenic ODS emissions were halted beginning in 2011, ozone is calculated to be higher by about 1-2{%} during the period 2030-2100 compared to a case of no additional ODS restrictions. Radiative forcing by 2100 would be about 0.23 W/m2 lower due to the elimination of N2O emissions and about 0.005 W/m2 lower due to destruction of the chlorofluorocarbon (CFC) bank. The ability of EESC to be a suitable metric for total ozone is also quantified. Responding to the recent suggestion that N2O should be considered an ODS, we provide an approach to incorporate N2O into the EESC formulation.

  4. An overview of the 2013 Las Vegas Ozone Study (LVOS): Impact of stratospheric intrusions and long-range transport on surface air quality

    NASA Astrophysics Data System (ADS)

    Langford, A. O.; Senff, C. J.; Alvarez, R. J.; Brioude, J.; Cooper, O. R.; Holloway, J. S.; Lin, M. Y.; Marchbanks, R. D.; Pierce, R. B.; Sandberg, S. P.; Weickmann, A. M.; Williams, E. J.

    2015-05-01

    The 2013 Las Vegas Ozone Study (LVOS) was conducted in the late spring and early summer of 2013 to assess the seasonal contribution of stratosphere-to-troposphere transport (STT) and long-range transport to surface ozone in Clark County, Nevada and determine if these processes directly contribute to exceedances of the National Ambient Air Quality Standard (NAAQS) in this area. Secondary goals included the characterization of local ozone production, regional transport from the Los Angeles Basin, and impacts from wildfires. The LVOS measurement campaign took place at a former U.S. Air Force radar station ∼45 km northwest of Las Vegas on Angel Peak (∼2.7 km above mean sea level, asl) in the Spring Mountains. The study consisted of two extended periods (May 19-June 4 and June 22-28, 2013) with near daily 5-min averaged lidar measurements of ozone and backscatter profiles from the surface to ∼2.5 km above ground level (∼5.2 km asl), and continuous in situ measurements (May 20-June 28) of O3, CO, (1-min) and meteorological parameters (5-min) at the surface. These activities were guided by forecasts and analyses from the FLEXPART (FLEXible PARTticle) dispersion model and the Real Time Air Quality Modeling System (RAQMS), and the NOAA Geophysical Research Laboratory (NOAA GFDL) AM3 chemistry-climate model. In this paper, we describe the LVOS measurements and present an overview of the results. The combined measurements and model analyses show that STT directly contributed to each of the three O3 exceedances that occurred in Clark County during LVOS, with contributions to 8-h surface concentrations in excess of 30 ppbv on each of these days. The analyses show that long-range transport from Asia made smaller contributions (<10 ppbv) to surface O3 during two of those exceedances. The contribution of regional wildfires to surface O3 during the three LVOS exceedance events was found to be negligible, but wildfires were found to be a major factor during exceedance events

  5. Ozone’s Impact on Public Health: Contributions from Indoor Exposures to Ozone and Products of Ozone-Initiated Chemistry

    PubMed Central

    Weschler, Charles J.

    2006-01-01

    Objective The associations between ozone concentrations measured outdoors and both morbidity and mortality may be partially due to indoor exposures to ozone and ozone-initiated oxidation products. In this article I examine the contributions of such indoor exposures to overall ozone-related health effects by extensive review of the literature as well as further analyses of published data. Findings Daily inhalation intakes of indoor ozone (micrograms per day) are estimated to be between 25 and 60% of total daily ozone intake. This is especially noteworthy in light of recent work indicating little, if any, threshold for ozone’s impact on mortality. Additionally, the present study estimates that average daily indoor intakes of ozone oxidation products are roughly one-third to twice the indoor inhalation intake of ozone alone. Some of these oxidation products are known or suspected to adversely affect human health (e.g., formaldehyde, acrolein, hydroperoxides, fine and ultrafine particles). Indirect evidence supports connections between morbidity/mortality and exposures to indoor ozone and its oxidation products. For example, cities with stronger associations between outdoor ozone and mortality tend to have residences that are older and less likely to have central air conditioning, which implies greater transport of ozone from outdoors to indoors. Conclusions Indoor exposures to ozone and its oxidation products can be reduced by filtering ozone from ventilation air and limiting the indoor use of products and materials whose emissions react with ozone. Such steps might be especially valuable in schools, hospitals, and childcare centers in regions that routinely experience elevated outdoor ozone concentrations. PMID:17035131

  6. 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.

  7. When will the Antarctic Ozone Hole Recover?

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Kawa, S. Randolph; Montzka, Steve

    2006-01-01

    The Antarctic ozone hole develops each year and culminates by early Spring. Antarctic ozone values have been monitored since 1979 using satellite observations from the .TOMS instrument. The severity of the hole has been assessed from TOMS using the minimum total ozone value from the October monthly mean (depth of the hole) and by calculating the average size during the September-October period. Ozone is mainly destroyed by halogen catalytic cycles, and these losses are modulated by temperature variations in the collar of the polar lower stratospheric vortex. In this presentation, we show the relationships of halogens and temperature to, both the size and depth of the hole. 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. The ozone hole will begin to show first signs of recovery in about 2023, and the hole will fully recover to pre-1980 levels in approximately 2070. This 2070 recovery is 20 years later than recent projections.

  8. When Will the Antarctic Ozone Hole Recover?

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Kawa, S. Randolph; Montzka, Steve

    2005-01-01

    The Antarctic ozone hole develops each year and culminates by early Spring. Antarctic ozone values have been monitored since 1979 using satellite observations from the TOMS instrument. The severity of the hole has been assessed from TOMS using the minimum total ozone value from the October monthly mean (depth of the hole) and by calculating the average size during the September-October period. Ozone is mainly destroyed by halogen catalytic cycles, and these losses are modulated by temperature variations in the collar of the polar lower stratospheric vortex. In this presentation, we show the relationships of halogens and temperature to both the size and depth of the hole. 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 will show estimates of both when the ozone hole will begin to show first signs of recovery, and when the hole will fully recover to pre-1980 levels.

  9. Higher Surface Ozone Concentrations Over the Chesapeake Bay than Over the Adjacent Land: Observations and Models from the DISCOVER-AQ and CBODAQ Campaigns

    NASA Technical Reports Server (NTRS)

    Goldberg, Daniel L.; Loughner, Christopher P.; Tzortziou, Maria; Stehr, Jeffrey W.; Pickering, Kenneth E.; Marufu, Lackson T.; Dickerson, Russell R.

    2013-01-01

    Air quality models, such as the Community Multiscale Air Quality (CMAQ) model, indicate decidedly higher ozone near the surface of large interior water bodies, such as the Great Lakes and Chesapeake Bay. In order to test the validity of the model output, we performed surface measurements of ozone (O3) and total reactive nitrogen (NOy) on the 26-m Delaware II NOAA Small Research Vessel experimental (SRVx), deployed in the Chesapeake Bay for 10 daytime cruises in July 2011 as part of NASA's GEO-CAPE CBODAQ oceanographic field campaign in conjunction with NASA's DISCOVER-AQ air quality field campaign. During this 10-day period, the EPA O3 regulatory standard of 75 ppbv averaged over an 8-h period was exceeded four times over water while ground stations in the area only exceeded the standard at most twice. This suggests that on days when the Baltimore/Washington region is in compliance with the EPA standard, air quality over the Chesapeake Bay might exceed the EPA standard. Ozone observations over the bay during the afternoon were consistently 10-20% higher than the closest upwind ground sites during the 10-day campaign; this pattern persisted during good and poor air quality days. A lower boundary layer, reduced cloud cover, slower dry deposition rates, and other lesser mechanisms, contribute to the local maximum of ozone over the Chesapeake Bay. Observations from this campaign were compared to a CMAQ simulation at 1.33 km resolution. The model is able to predict the regional maximum of ozone over the Chesapeake Bay accurately, but NOy concentrations are significantly overestimated. Explanations for the overestimation of NOy in the model simulations are also explored

  10. Higher surface ozone concentrations over the Chesapeake Bay than over the adjacent land: Observations and models from the DISCOVER-AQ and CBODAQ campaigns

    NASA Astrophysics Data System (ADS)

    Goldberg, Daniel L.; Loughner, Christopher P.; Tzortziou, Maria; Stehr, Jeffrey W.; Pickering, Kenneth E.; Marufu, Lackson T.; Dickerson, Russell R.

    2014-02-01

    Air quality models, such as the Community Multiscale Air Quality (CMAQ) model, indicate decidedly higher ozone near the surface of large interior water bodies, such as the Great Lakes and Chesapeake Bay. In order to test the validity of the model output, we performed surface measurements of ozone (O3) and total reactive nitrogen (NOy) on the 26-m Delaware II NOAA Small Research Vessel experimental (SRVx), deployed in the Chesapeake Bay for 10 daytime cruises in July 2011 as part of NASA's GEO-CAPE CBODAQ oceanographic field campaign in conjunction with NASA's DISCOVER-AQ air quality field campaign. During this 10-day period, the EPA O3 regulatory standard of 75 ppbv averaged over an 8-h period was exceeded four times over water while ground stations in the area only exceeded the standard at most twice. This suggests that on days when the Baltimore/Washington region is in compliance with the EPA standard, air quality over the Chesapeake Bay might exceed the EPA standard. Ozone observations over the bay during the afternoon were consistently 10-20% higher than the closest upwind ground sites during the 10-day campaign; this pattern persisted during good and poor air quality days. A lower boundary layer, reduced cloud cover, slower dry deposition rates, and other lesser mechanisms, contribute to the local maximum of ozone over the Chesapeake Bay. Observations from this campaign were compared to a CMAQ simulation at 1.33 km resolution. The model is able to predict the regional maximum of ozone over the Chesapeake Bay accurately, but NOy concentrations are significantly overestimated. Explanations for the overestimation of NOy in the model simulations are also explored.

  11. Ozone Trend Detectability

    NASA Technical Reports Server (NTRS)

    Campbell, J. W. (Editor)

    1981-01-01

    The detection of anthropogenic disturbances in the Earth's ozone layer was studied. Two topics were addressed: (1) the level at which a trend in total ozoning is detected by existing data sources; and (2) empirical evidence in the prediction of the depletion in total ozone. Error sources are identified. The predictability of climatological series, whether empirical models can be trusted, and how errors in the Dobson total ozone data impact trend detectability, are discussed.

  12. Sequential Camouflage of the arachno-6,9-C2B8H14 Cage by Substituents.

    PubMed

    Bakardjiev, Mario; Štíbr, Bohumil; Holub, Josef; Tok, Oleg L; Švec, Petr; Růžičková, Zdeňka; Růžička, Aleš

    2016-07-18

    Sequential methylation of arachno-6,9-C2B8H14 (1) led to a series of methyl derivatives and finally to the camouflaging of all boron positions by mixed persubstitution. Thus, deprotonation of 1 produced the [arachno-6,9-C2B8H13] anion (1(-)), the methylation of which with MeI in tetrahydrofuran proceeded on the open-face boron vertexes with the formation of 5-Me-arachno-6,9-C2B8H13 (2; yield 28%) and 5,8-Me2-arachno-6,9-C2B8H12 (3; yield 36%). Observed in this reaction was also a side formation of 2-Me-closo-1,6-C2B8H9 (4; yield 6%).The electrophilic AlCl3-catalyzed CH3(+) attack of the neutral 1 in neat MeI at ambient temperature afforded 1,3-Me2-arachno-6,9-C2B8H12 (5), while a 76-h heating at 120 °C generated a mixture of the di- and triiodo derivatives 1,2,3,4,8,10-Me6-5,7-I2-arachno-6,9-C2B8H6 (6) and 1,2,3,4,7-Me5-5,7,10-I3-arachno-6,9-C2B8H6 (7). On the other hand, a HOTf-catalyzed reaction between 1 and MeOTf at reflux resulted in the isolation of 2-TfO-1,3.4,5,7,8,10-Me7-arachno-6,9-C2B8H6 (8; Tf = CF3SO2; yield 65%). The compounds were characterized by multinuclear ((11)B, (1)H, (13)C, and (19)F) NMR spectroscopy, mass spectrometry, and elemental analysis, and the structures of compounds 1, 1(-), 5, and 6 were established by X-ray diffraction analysis. PMID:27351461

  13. Two-component Langmuir monolayers and LB films of DPPC with partially fluorinated alcohol (F8H9OH).

    PubMed

    Nakahara, Hiromichi; Hirano, Chikayo; Shibata, Osamu

    2013-01-01

    The interaction of (perfluorooctyl)nonanol (F8H9OH) with dipalmitoylphosphatidylcholine (DPPC) was systematically studied in two-component monolayers at air-water interface. The thermodynamic property and phase morphology of the monolayers were investigated by isotherm measurements and several microscopic methods such as Brewster angle microscopy, fluorescence microscopy, and atomic force microscopy (AFM). The AFM topographies for Langmuir-Blodgett films of F8H9OH exhibit the formation of monodispersed surface micelles. In the two-component system, the incorporation of F8H9OH induces condensation (or solidification) of DPPC monolayers. The excess Gibbs free energy and interaction parameter (or energy) of the two components were calculated from the isotherm data. Both the phase transition pressure for the coexistence of ordered and disordered phases and collapse pressure of monolayers vary with the mole fraction of F8H9OH, indicating binary miscibility between F8H9OH and DPPC within a monolayer state. The miscibility is also confirmed visually by in situ and ex situ microscopy at micro- and nanometer scales.

  14. Structural changes in wood during ozonation

    NASA Astrophysics Data System (ADS)

    Ben'ko, E. M.; Manisova, O. R.; Murav'eva, G. P.; Lunin, V. V.

    2013-07-01

    It is found that ozone treatment of aspen wood leads to changes in its structural characteristics, i.e., its specific surface area and the crystallinity index of cellulose. Using optical microscopy, it is shown that ozonation is accompanied by a decrease in the average size and visible surface of wood particles. The values for the specific area of the outer surface of samples are calculated. The specific surface area available to the enzyme molecules is determined from data on the adsorption of inert protein hemoglobin on wood. It is shown that this value is an order of magnitude higher than that of the outer surface and increases considerably for an ozonized sample. Based on the results from X-ray analysis, it is established that the structure of cellulose is disordered during ozone delignification, as is indicated by a reduction in the crystallinity index and crystallite sizes.

  15. Ozone Antimicrobial Efficacy

    EPA Science Inventory

    Ozone is a potent germicide that has been used extensively for water purification. In Europe, 90 percent of the municipal water systems are treated with ozone, and in France, ozone has been used to treat drinking water since 1903. However, there is limited information on the bioc...

  16. Click Dehydrogenation of Carbon-Substituted nido-5,6-C2B8H12 Carboranes: A General Route to closo-1,2-C2B8H10 Derivatives.

    PubMed

    Tok, Oleg L; Bakardjiev, Mario; Štíbr, Bohumil; Hnyk, Drahomír; Holub, Josef; Padělková, Zdenka; Růžička, Aleš

    2016-09-01

    Triethylamine-catalyzed dehydrogenation of carbon-disubstituted dicarbaboranes 5,6-R2-nido-5,6-C2B8H10 [1, where R = H (1a), Me (1b), and Ph (1c)] in refluxing acetonitrile leads to a high-yield (up to 85-95%) formation of a series of dicarbaboranes 1,2-R2-closo-1,2-C2B8H8 (2). The monosubstituted 6-R-nido-5,6-C2B8H11 (3) analogues [where R = Ph (3a), naph (1-naphthyl; 3b), Bu (3c)] afforded 1-R-1,2-closo C2B8H9 (4) isomers [where R = Ph (4a), naph (4b), n-Bu (4c)] as the main products; compounds 4a and 4c were accompanied by 2-R-1,2-C2B8H9 (5) isomers (total yields up to 90%), with the 4/5 molar ratio being strongly dependent on the nature of R (4:1 and 1:1, respectively). All of these cage-closure reactions are supposed to proceed via the stage of the corresponding Et3NH(+) salts of nido anions [5,6-R2-5,6-C2B8H9](-) (1(-)) and [6-R-5,6-C2B8H10](-) (3(-)), which lose H2 and Et3N upon heating (dehydrodeamination). The cage-closure mechanisms leading to closo isomers 2, 4, and 5 have been substantiated by B3LYP/6-31+G* calculations of the reaction profile for a simple 1a(-) → 2a + H(-) conversion. All of the compounds isolated have been characterized by multinuclear ((11)B, (1)H, and (13)C) NMR spectroscopy, mass spectrometry, and elemental analyses, and the structure of 1-Ph-closo-1,2-C2B8H9 (4a) was established by an X-ray diffraction study. PMID:27551885

  17. Ozone drinking water treatment handbook

    SciTech Connect

    Rice, R.G.

    1990-01-01

    This book explains how ozone can be used to provide primary disinfection, while minimizing halogenated by-products. This is of use to those who design pilot plant studies in full scale ozone plants-and those who employ ozone and regulatory personnel. Detailed section on components of an ozonization system outlines feed gas preparation (air and oxygen), ozone generation, ozone contacting, ozone off gas destruction, monitoring and control of ozonation systems, engineering aspects of ozone, cost factors in ozone technology, case histories (European and U.S.).

  18. Contributions of regional air pollutant emissions to ozone and fine particulate matter-related mortalities in eastern U.S. urban areas.

    PubMed

    Hou, Xiangting; Strickland, Matthew J; Liao, Kuo-Jen

    2015-02-01

    Ground-level ozone and fine particulate matter (PM2.5) are associated with adverse human health effects such as lung structure dysfunction, inflammation and infection, asthma, and premature deaths. This study estimated contributions of emissions of anthropogenic nitrogen oxides (NOx), volatile organic compounds (VOCs) and sulfur dioxides (SO2) from four regions to summertime (i.e., June, July, and August) ozone and PM2.5-related mortalities in seven major Metropolitan Statistical Areas (MSAs with more than 4 million people) in the eastern United States (U.S.). A photochemical transport model, Community Multi-scale Air Quality (CMAQ) with sensitivity analyses, was applied to quantify the contribution of the regional anthropogenic emissions to ambient ozone and PM2.5 concentrations in the seven MSAs. The results of the sensitivity analysis, along with estimates of concentration-response from published epidemiologic studies, were used to estimate excess deaths associated with changes in ambient daily 8-h average ozone and daily PM2.5 concentrations during the summer of 2007. The results show that secondary PM2.5 (i.e., PM2.5 formed in the atmosphere) had larger effects on mortality (95% confidence interval (C.I.) ranged from 700 to 3854) than ambient ozone did (95% C.I. was 470-1353) in the seven MSAs. Emissions of anthropogenic NOx, VOCs and SO2 from the northeastern U.S. could cause up to about 2500 ozone and PM2.5-related deaths in the urban areas examined in this study. The results also show that the contributions of emissions from electrical generating units (EGUs) and anthropogenic non-EGU sources to ozone-related mortality in the MSAs were similar. However, emissions from EGUs had a more significant impact on PM2.5-related deaths than anthropogenic emissions from non-EGUs sources did. Anthropogenic NOx and VOCs emissions from the regions where the MSAs are located had the most significant contributions to ozone-related mortalities in the eastern U.S. urban

  19. Contributions of regional air pollutant emissions to ozone and fine particulate matter-related mortalities in eastern U.S. urban areas.

    PubMed

    Hou, Xiangting; Strickland, Matthew J; Liao, Kuo-Jen

    2015-02-01

    Ground-level ozone and fine particulate matter (PM2.5) are associated with adverse human health effects such as lung structure dysfunction, inflammation and infection, asthma, and premature deaths. This study estimated contributions of emissions of anthropogenic nitrogen oxides (NOx), volatile organic compounds (VOCs) and sulfur dioxides (SO2) from four regions to summertime (i.e., June, July, and August) ozone and PM2.5-related mortalities in seven major Metropolitan Statistical Areas (MSAs with more than 4 million people) in the eastern United States (U.S.). A photochemical transport model, Community Multi-scale Air Quality (CMAQ) with sensitivity analyses, was applied to quantify the contribution of the regional anthropogenic emissions to ambient ozone and PM2.5 concentrations in the seven MSAs. The results of the sensitivity analysis, along with estimates of concentration-response from published epidemiologic studies, were used to estimate excess deaths associated with changes in ambient daily 8-h average ozone and daily PM2.5 concentrations during the summer of 2007. The results show that secondary PM2.5 (i.e., PM2.5 formed in the atmosphere) had larger effects on mortality (95% confidence interval (C.I.) ranged from 700 to 3854) than ambient ozone did (95% C.I. was 470-1353) in the seven MSAs. Emissions of anthropogenic NOx, VOCs and SO2 from the northeastern U.S. could cause up to about 2500 ozone and PM2.5-related deaths in the urban areas examined in this study. The results also show that the contributions of emissions from electrical generating units (EGUs) and anthropogenic non-EGU sources to ozone-related mortality in the MSAs were similar. However, emissions from EGUs had a more significant impact on PM2.5-related deaths than anthropogenic emissions from non-EGUs sources did. Anthropogenic NOx and VOCs emissions from the regions where the MSAs are located had the most significant contributions to ozone-related mortalities in the eastern U.S. urban

  20. Monitoring and future projections of the Antarctic Ozone Hole using the new Ozone Mapping and Profiler Suite (OMPS)

    NASA Astrophysics Data System (ADS)

    Kramarova, N. A.; Newman, P. A.; Nash, E. R.; Bhartia, P. K.; McPeters, R. D.; Rault, D. F.; Seftor, C. J.; Xu, P.

    2013-12-01

    Using the new Ozone Mapping and Profiler Suite (OMPS), launched October 2011 on board the Suomi National Polar-orbiting Partnership satellite, we have studied the structure and evolution of the 2012 and 2013 ozone holes. The 1st ozone hole observations by OMPS began in 2012. We quality check the OMPS measurements by comparing to other satellite instruments (Aura MLS, OMI and SBUV) and ozone sonde balloon measurements. The comparisons reveal that OMPS is producing excellent Antarctic ozone hole information, and, thus, OMPS data can be used to continue the historical record of Antarctic ozone observations. In 2012 the ozone hole developed quite normally in the August to-late September 2012 period, but disappeared much more rapidly during the late-September to November period than it would be expected in a normal year. This resulted in the second weakest ozone hole observed since 1988. Some have suggested that the rapid 2012 disappearance is evidence that the Montreal Protocol is working. However, the development of the ozone hole in August and September is largely driven by chlorine and bromine from human-produced compounds, and the normal development of the ozone hole in August-September 2012 suggests that chlorine and bromine levels were roughly the same as previous years. At the same time, observations from meteorological data show that there were stronger than average weather systems, faster warming during the September -November period, and stronger vertical motions, that led to a rapid decay of the 2012 ozone hole. Hence, the weak ozone hole of 2012 is not evidence that the Montreal Protocol has impacted the ozone hole. The characteristics of the 2013 ozone hole, as observed by OMPS, will also be shown in the presentation. Model predictions suggest that the ozone hole will begin showing signs of recovery in about 2018, and it will be fully recovered back to 1980 levels in about 2065. We will update projections of the ozone hole recovery using a parametric model

  1. Neutron resonance averaging

    SciTech Connect

    Chrien, R.E.

    1986-10-01

    The principles of resonance averaging as applied to neutron capture reactions are described. Several illustrations of resonance averaging to problems of nuclear structure and the distribution of radiative strength in nuclei are provided. 30 refs., 12 figs.

  2. Paradoxes in Averages.

    ERIC Educational Resources Information Center

    Mitchem, John

    1989-01-01

    Examples used to illustrate Simpson's paradox for secondary students include probabilities, university admissions, batting averages, student-faculty ratios, and average and expected class sizes. Each result is explained. (DC)

  3. Impacts of summer ozone exposure on the growth and overwintering of UK upland vegetation

    NASA Astrophysics Data System (ADS)

    Hayes, Felicity; Mills, Gina; Williams, Philip; Harmens, Harry; Büker, Patrick

    The effects of ozone exposure on species of an upland grassland were assessed. Thirty-three species from Snowdonia, North Wales, UK, were exposed for 10 weeks to a weekly episodic ozone regime in solardomes representing predicted future concentrations. Two solardomes were used as controls, with ozone added to charcoal-filtered air to give a continuous ozone concentration of 30 ppb (O 3(30)). A weekly episodic ozone regime was applied to two other solardomes, with concentrations rising for 8 h per day to 80 ppb on day 1, 100 ppb on days 2 and 3, and 80 ppb on day 4; ozone concentrations remained at 30 ppb at all other times (O 3(30+peaks)). The control and background ozone concentrations of 30 ppb were maintained throughout the night as well as during the daytime. During exposure to the episodic ozone regime, some species were sensitive to ozone and showed ozone-specific leaf injury symptoms (e.g . Carex echinata) and/or premature senescence (e.g. Festuca rubra) and/or changes in above-ground biomass (e.g. Armeria maritima), whereas other species (e.g Holcus lanatus and Carex demissa) showed no effects. Some species, although showing no effects during the 10-week ozone exposure, showed carry-over effects on biomass the following spring, after a winter period of ambient ozone exposure (e.g. Galium saxatile, Nardus stricta and Saxifraga stellaris). The carry-over effects shown in this study indicate the potential ecological impact of ozone on semi-natural vegetation species and indicate the importance of longer-term studies on the effects of ozone on plants.

  4. Effects of leg activity and ambient barometric pressure on foot swelling and lower-limb skin temperature during 8 h of sitting.

    PubMed

    Noddeland, H; Winkel, J

    1988-01-01

    Prolonged immobilization in an upright position often leads to discomfort and oedema in the feet of otherwise healthy subjects. To determine the significance of leg activity and ambient pressure on oedema formation, skin temperature (Tsk) and discomfort, 6 volunteers sat for 8 h with one leg immobilized and the other spontaneously active; one day at "sea level" (750 mmHg) and one day at reduced barometric pressure (540 mmHg). Foot swelling was measured by water plethysmography. Leg movements were continuously monitored by a Vitalog computer, and foot discomfort was estimated by analog-visual scales. The 8 hour swelling averaged 5.7% in the inactive foot, and 2.7% in the active foot (p less than 0.001). Tsk of the inactive foot levelled off towards ambient temperature (21 degrees C) within 4 h. For the active foot this fall was reduced by 2-3 degrees C (p less than 0.025). The increase in foot discomfort during the day was lowest in the active foot (p less than 0.005). High foot Tsk was associated with a high foot swelling rate. Reduced ambient barometric pressure had no effects on foot swelling or Tsk. It is concluded that modest leg activity during 8 h of sitting has several effects on the circulation in the feet: some effects promote and some prevent oedema formation. However, the net result is a reduction in foot swelling.

  5. Ozone and the stratosphere

    NASA Technical Reports Server (NTRS)

    Shimazaki, Tatsuo

    1987-01-01

    It is shown that the stratospheric ozone is effective in absorbing almost all radiation below 300 nm at heights below 300 km. The distribution of global ozone in the troposphere and the lower stratosphere, and the latitudinal variations of the total ozone column over four seasons are considered. The theory of the ozone layer production is discussed together with catalytic reactions for ozone loss and the mechanisms of ozone transport. Special attention is given to the anthropogenic perturbations, such as SST exhaust gases and freon gas from aerosol cans and refrigerators, that may cause an extensive destruction of the stratospheric ozone layer and thus have a profound impact on the world climate and on life.

  6. Stress ethylene evolution of bean plants—a parameter indicating ozone pollution

    NASA Astrophysics Data System (ADS)

    Stan, Hans-Jürgen; Schicker, Sieglinde; Kassner, Helmut

    Bean plants treated with varying ozone concentrations for varying exposure times showed increased rates of ethylene production compared with controls. A standard method was worked out in which primary leaves of bean plants were encapsulated in 250 ml Erlenmeyer flasks after exposure. The amount of ethylene produced was determined by gas chromatography after about 24 h. The 'no effect level' of the bean plant was found to be 100 ppb ozone because there was no significant stress ethylene production even after 12 h fumigation. A treatment with 150 ppb ozone induced the beginning of stress ethylene production after about 8 h. With higher ozone concentrations shorter exposure times are necessary to induce a first response. Stress ethylene production correlates better with ozone concentration than with exposure time comparing the same products of concentration and time.

  7. A global tropospheric ozone climatology from trajectory-mapped ozone soundings

    NASA Astrophysics Data System (ADS)

    Liu, G.; Liu, J. J.; Tarasick, D. W.; Fioletov, V. E.; Jin, J. J.; Moeni, O.; Liu, X.; Sioris, C. E.

    2013-05-01

    A global three-dimensional (i.e. latitude, longitude, altitude) climatology of tropospheric ozone is derived from the ozone sounding record by trajectory mapping. Approximately 52 000 ozonesonde profiles from more than 100 stations worldwide since 1962 are used. The small number of stations causes the set of ozone soundings to be sparse in geographical spacing. Here, forward and backward trajectory calculations are performed for each sounding to map ozone measurements to a number of other locations, and so to fill in the spatial domain. This is possible because the lifetime of ozone in the troposphere is of the order of weeks. This physically-based interpolation method offers obvious advantages over typical statistical interpolation methods. The trajectory-mapped ozone values show reasonable agreement, where they overlap, to the actual soundings, and the patterns produced separately by forward and backward trajectory calculations are similar. Major regional features of the tropospheric ozone distribution are clearly evident in the global maps. An interpolation algorithm based on spherical functions is further used for smoothing and to fill in remaining data gaps. The resulting three-dimensional global tropospheric ozone climatology facilitates visualization and comparison of different years, decades, and seasons, and offers some intriguing insights into the global variation of tropospheric ozone. It will be useful for climate and air quality model initialization and validation, and as an a priori climatology for satellite data retrievals. Further division of the climatology into decadal averages provides a global view of tropospheric ozone trends, which appear to be surprisingly modest over the last four decades.

  8. 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.

  9. Microbubble enhanced ozonation process for advanced treatment of wastewater produced in acrylic fiber manufacturing industry.

    PubMed

    Zheng, Tianlong; Wang, Qunhui; Zhang, Tao; Shi, Zhining; Tian, Yanli; Shi, Shanshan; Smale, Nicholas; Wang, Juan

    2015-04-28

    This work investigated microbubble-ozonation for the treatment of a refractory wet-spun acrylic fiber wastewater in comparison to macrobubble-ozonation. CODcr, NH3-N, and UV254 of the wastewater were removed by 42%, 21%, and 42%, respectively in the microbubble-ozonation, being 25%, 9%, and 35% higher than the removal rates achieved by macrobubble-ozonation at the same ozone dose. The microbubbles (with average diameter of 45μm) had a high concentration of 3.9×10(5) counts/mL at a gas flow rate of 0.5L/min. The gas holdup, total ozone mass-transfer coefficient, and average ozone utilization efficiency in the microbubble-ozonation were 6.6, 2.2, and 1.5 times higher than those of the macrobubble-ozonation. Greater generation of hydroxyl radicals and a higher zeta potential of the bubbles were also observed in the microbubble ozonation process. The biodegradability of the wastewater was also significantly improved by microbubble-ozonation, which was ascribed to the enhanced degradation of alkanes, aromatic compounds, and the many other bio-refractory organic compounds in the wastewater. Microbubble-ozonation can thus be a more effective treatment process than traditional macrobubble-ozonation for refractory wastewater produced by the acrylic fiber manufacturing industry.

  10. Microbubble enhanced ozonation process for advanced treatment of wastewater produced in acrylic fiber manufacturing industry.

    PubMed

    Zheng, Tianlong; Wang, Qunhui; Zhang, Tao; Shi, Zhining; Tian, Yanli; Shi, Shanshan; Smale, Nicholas; Wang, Juan

    2015-04-28

    This work investigated microbubble-ozonation for the treatment of a refractory wet-spun acrylic fiber wastewater in comparison to macrobubble-ozonation. CODcr, NH3-N, and UV254 of the wastewater were removed by 42%, 21%, and 42%, respectively in the microbubble-ozonation, being 25%, 9%, and 35% higher than the removal rates achieved by macrobubble-ozonation at the same ozone dose. The microbubbles (with average diameter of 45μm) had a high concentration of 3.9×10(5) counts/mL at a gas flow rate of 0.5L/min. The gas holdup, total ozone mass-transfer coefficient, and average ozone utilization efficiency in the microbubble-ozonation were 6.6, 2.2, and 1.5 times higher than those of the macrobubble-ozonation. Greater generation of hydroxyl radicals and a higher zeta potential of the bubbles were also observed in the microbubble ozonation process. The biodegradability of the wastewater was also significantly improved by microbubble-ozonation, which was ascribed to the enhanced degradation of alkanes, aromatic compounds, and the many other bio-refractory organic compounds in the wastewater. Microbubble-ozonation can thus be a more effective treatment process than traditional macrobubble-ozonation for refractory wastewater produced by the acrylic fiber manufacturing industry. PMID:25681716

  11. Mechanism and Trend Change of Sudden Increase of Total Ozone in Seoul

    NASA Astrophysics Data System (ADS)

    Cho, H.; Park, S.; Kim, J.; Lee, Y.; Mok, J.; Lee, Y.

    2009-12-01

    The total ozone column values have been observed by numerous satellites including TOMS and OMI, and extensive network of ground-based measurements (Dobson & Brewer Spectrophotometer etc.), over long time period over the globe, in which statistical long-term trend or ozone recovery are analyzed. In March 14th, 2006, sudden increase of the total ozone values are observed in East Asia, where the mixing ratio of ozone in ozonesonde data at Sapporo (14th Mar, 2006) increased between 10 and 15km remarkably. In general, stratospheric ozone does not change that abruptly. However from late winter to early spring, sudden increase of total ozone values were observed over the North-east Eurasian Continent and the Sea of Ohotsuku. In the beginning of this periods, observed total ozone values increased by more than 40~50 DU, compared with previous day’s value, maintaining abnormal condition for a few days. This mechanism is not understood clearly but in previous studies, this effect occurred by secondary ozone peak that is caused by Stratosphere-Troposphere Exchange (STE). To explain this phenomenon, we select the highest 5% of total ozone values observed in Seoul since 1985 and analyze the back trajectory and NCEP/NCAR reanalysis data between 10~20km at the same time. In the events of sudden total ozone increase, air parcels of 10~15km altitudes came mostly from arctic region, which is statistically evident. These `arctic origin air’ are ozone-rich in mixing ratio thus results in the secondary ozone peak and ozone enhancements in Seoul. These enhancements were occurred several times in a month. Thus, it changes the average of total ozone and climatological values, which affects the trend of stratospheric ozone recovery. In this study, using the ozonesonde and total ozone data, we separate the total ozone and sudden enhancement of ozone in Upper troposphere/ Lower Stratosphere and examine the effect of these changes on the ozone recovery trend in Seoul.

  12. The F8H Glycosyltransferase is a Functional Paralog of FRA8 Involved in Glucuronoxylan Biosynthesis in Arabidopsis

    EPA Science Inventory

    The FRAGILE FIBER8 gene was previously shown to be required for the biosynthesis of the reducing end tetrasaccharide sequence of glucuronoxylan (GX) in Arabidopsis thaliana. Here, we demonstrate that F8H, a close homolog of FRA8, is a functional ortholog of FRA8 involved in GX bi...

  13. Regional-scale transport of air pollutants: impacts of Southern California emissions on Phoenix ground-level ozone concentrations

    NASA Astrophysics Data System (ADS)

    Li, J.; Georgescu, M.; Hyde, P.; Mahalov, A.; Moustaoui, M.

    2015-08-01

    In this study, WRF-Chem is utilized at high resolution (1.333 km grid spacing for the innermost domain) to investigate impacts of southern California anthropogenic emissions (SoCal) on Phoenix ground-level ozone concentrations ([O3]) for a pair of recent exceedance episodes. First, WRF-Chem control simulations, based on the US Environmental Protection Agency (EPA) 2005 National Emissions Inventories (NEI05), are conducted to evaluate model performance. Compared with surface observations of hourly ozone, CO, NOX, and wind fields, the control simulations reproduce observed variability well. Simulated [O3] are comparable with the previous studies in this region. Next, the relative contribution of SoCal and Arizona local anthropogenic emissions (AZ) to ozone exceedances within the Phoenix metropolitan area is investigated via a trio of sensitivity simulations: (1) SoCal emissions are excluded, with all other emissions as in Control; (2) AZ emissions are excluded with all other emissions as in Control; and (3) SoCal and AZ emissions are excluded (i.e., all anthropogenic emissions are eliminated) to account only for Biogenic emissions and lateral boundary inflow (BILB). Based on the USEPA NEI05, results for the selected events indicate the impacts of AZ emissions are dominant on daily maximum 8 h average (DMA8) [O3] in Phoenix. SoCal contributions to DMA8 [O3] for the Phoenix metropolitan area range from a few ppbv to over 30 ppbv (10-30 % relative to Control experiments). [O3] from SoCal and AZ emissions exhibit the expected diurnal characteristics that are determined by physical and photochemical processes, while BILB contributions to DMA8 [O3] in Phoenix also play a key role. Finally, ozone transport processes and pathways within the lower troposphere are investigated. During daytime, pollutants (mainly ozone) near the Southern California coasts are pumped into the planetary boundary-layer over the Southern California desert through the mountain chimney and pass

  14. Regional-scale transport of air pollutants: impacts of southern California emissions on Phoenix ground-level ozone concentrations

    NASA Astrophysics Data System (ADS)

    Li, J.; Georgescu, M.; Hyde, P.; Mahalov, A.; Moustaoui, M.

    2015-03-01

    In this study, WRF-Chem is utilized at high-resolution (1.333 km grid spacing for the innermost domain) to investigate impacts of southern California anthropogenic emissions (SoCal) on Phoenix ground-level ozone concentrations ([O3]) for a pair of recent exceedance episodes. First, WRF-Chem Control simulations are conducted to evaluate model performance. Compared with surface observations of hourly ozone, CO, NOx, and wind fields, the Control simulations reproduce observed variability well. Simulated [O3] are within acceptance ranges recommended by the Environmental Protection Agency (EPA) that characterize skillful experiments. Next, the relative contribution of SoCal and Arizona local anthropogenic emissions (AZ) to ozone exceedance within the Phoenix metropolitan area is investigated via a trio of sensitivity simulations: (1) SoCal emissions are excluded, with all other emissions as in Control; (2) AZ emissions are excluded with all other emissions as in Control; and (3) SoCal and AZ emissions are excluded (i.e., all anthropogenic emissions are eliminated) to account only for biogenic emissions [BEO]. Results for the selected events indicate the impacts of AZ emissions are dominant on daily maximum 8 h average (DMA8) [O3] in Phoenix. SoCal contributions to DMA8 [O3] for the Phoenix metropolitan area range from a few ppbv to over 30 ppbv (10-30% relative to Control experiments). [O3] from SoCal and AZ emissions exhibit the expected diurnal characteristics that are determined by physical and photochemical processes, while BEO contributions to DMA8 [O3] in Phoenix also play a key role. Finally, ozone transport processes and pathways within the lower troposphere are investigated. During daytime, pollutants (mainly ozone) near the southern California coasts are pumped into the planetary boundary-layer over the southern California desert through the mountain chimney and pass channel effects, aiding eastward transport along the desert air basins in southern California

  15. 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.; Briel, D.

    1978-01-01

    The average amount of ozone measured in the cabins of two B-747 airliners varied from 40 percent to 80 percent of the atmospheric concentrations without special ozone destruction systems. A charcoal filter in the cabin air inlet system of one B-747 reduced the ozone to about 5 percent of the atmospheric concentration. A Learjet 23 was also instrumented with monitors to measure simultaneously the atmospheric and ozone concentrations. Results indicate that a significant portion of the atmospheric ozone is not destroyed in the pressurization system and remains in the aircraft cabin of the Learjet. For the two cabin configurations tested, the ozone retentions were 63 and 41 percent of the atmospheric ozone concentrations. Ozone concentrations measured in the cabin near the conditioned-air outlets were reduced only slightly from atmospheric ozone concentrations. It is concluded that a constant difference between ozone concentrations inside and outside the cabin does not exist.

  16. Erythrocyte survival in sheep exposed to ozone

    SciTech Connect

    Moore, G.S.; Calabrese, E.J.; Labato, F.J.

    1981-07-01

    Erythrocyte survival studies in the Dorset ewe using chromium 51 were performed. The purpose of the study was to determine if ozone exposure produces decreased cell survival which may be the result of premature erythrocyte aging. This strain of sheep has an erythrocyte glucose-6-phosphate dehydrogenase (G6PD) activity that is very low, being comparable to human A-variants with G6PD deficiency. Ozone exposure may produce hemolytic effects in G6PD deficients more readily than in erythrocytes with normal activity. A decrease in hematocrit was observed in the ozone exposed groups. With respect to red cell destruction, ozone does not appear to act immediately, but rather there appears to be a delayed effect. At 0.25 ppM ozone, the group reached the 50% remaining level an average of 1 day sooner than the control group. There was no significant difference between control and exposed groups at the 0.50 ppM and 0.70 ppM levels. Also, the results demonstrate a net decrease in hematocrit which is greater for 0.25 ppM ozone than any other exposure level. (RJC)

  17. Interannual Variability of Ozone and Ultraviolet Exposure

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Piacentini, R. D.; Ziemke, J.; Celarier, E.; Larko. D.

    1999-01-01

    Annual zonal averages of ozone amounts from Nimbus-7/TOMS (Total Ozone Mapping Spectrometer) (1979 to 1992) are used to estimate the interannual variability of ozone and UVB (290 - 315 nm) irradiance between plus or minus 60 deg. latitude. Clear-sky interannual ozone and UVB changes are mainly caused by the Quasi Biennial Oscillation (QBO) of stratospheric winds, and can amount to plus or minus 15% at 300 nm and plus or minus 5% at 310 nm (or erythemal irradiance) at the equator and at middle latitudes. Near the equator, the interannual variability of ozone amounts and UV irradiance caused by the combination of the 2.3 year QBO and annual cycles implies that there is about a 5-year periodicity in UVB variability. At higher latitudes, the appearance of the interannual UVB maximum is predicted by the QBO, but without the regular periodicity. The 5-year periodic QBO effects on UVB irradiance are larger than the currently evaluated long-term changes caused by the decrease in ozone amounts.

  18. Adaptation to ozone: duration of effect

    SciTech Connect

    Horvath, S.M.; Gliner, J.A.; Folinsbee, L.J.

    1981-05-01

    Repeated ozone exposure induces an adaptative response whereby subsequent ozone exposure induces little or no pulmonary function change. The time course of the adaptation and the persistence of this adaptation was determined in 24 subjects. Subjects were studied for 125 min while they exercised intermittently. They were exposed to filtered air for 1 day and then in the next week for 5 consecutive days to 0.5 ppm ozone. After the fifth day, subjects were randomly assigned to return for one more ozone exposure at 1, 2, or 3 wk. The greatest decrement in FEV1 occurred on the second day of exposure. The number of consecutive ozone exposures required to produce adaptation varied from 2 to 5 days. Persistence of adaptation in ozone-sensitive subjects (initial decrease in FEV1 greater than 10%) showed marked individual variability, but the duration of adaptation was shortest for the more sensitive subjects. Adaptation, on the average, lasted for less than 2 wk, being as short as 7 days and as long as 20 days. We concluded that more sensitive subjects required more daily sequential exposures in order to adapt.

  19. Ozone columns obtained by ground-based remote sensing in Kiev for Aura Ozone Measuring Instrument validation

    NASA Astrophysics Data System (ADS)

    Shavrina, A. V.; Pavlenko, Y. V.; Veles, A.; Syniavskyi, I.; Kroon, M.

    2007-12-01

    Ground-based observations with a Fourier transform spectrometer in the infrared region (FTIR) were performed in Kiev (Ukraine) during the time frames August-October 2005 and June-October 2006 within the Ozone Monitoring Instrument (OMI) validation project 2907 entitled "OMI validation by ground based remote sensing: ozone columns and profiles" in the frame of the international European Space Agency/Netherlands Agency for Aerospace Programmes/Royal Dutch Meteorological Institute OMI Announcement of Opportunity effort. Ozone column data for 2005 were obtained by modeling the ozone spectral band at 9.6 μm with the radiative transfer code MODTRAN3.5. Our total ozone column values were found to be lower than OMI Differential Optical Absorption Spectroscopy (DOAS) total ozone column data by 8-10 Dobson units (DU, 1 DU = 0.001 atm cm) on average, while our observations have a relatively small standard error of about 2 DU. Improved modeling of the ozone spectral band, now based on HITRAN-2004 spectral data as calculated by us, moves our results toward better agreement with the OMI DOAS total ozone column data. The observations made during 2006 with a modernized FTIR spectrometer and higher signal-to-noise ratio were simulated by the MODTRAN4 model computations. For ozone column estimates the Aqua Atmospheric Infrared Sounder satellite water vapor and temperature profiles were combined with the Aura Microwave Limb Sounder stratospheric ozone profiles and Tropospheric Emission Monitoring Internet Service-Koninklijk Nederlands Meteorologisch Instituut climatological profiles to create a priori input files for spectral modeling. The MODTRAN4 estimates of ozone columns from the 2006 observations compare rather well with the OMI total ozone column data: standard errors are of 1.11 DU and 0.68 DU, standard deviation are of 8.77 DU and 5.37 DU for OMI DOAS and OMI Total Ozone Mapping Spectrometer, respectively.

  20. Ozone-Initiated Chemistry in an Occupied Simulated AircraftCabin

    SciTech Connect

    Weschler, C.J.; Wisthaler, A.; Cowlind, S.; Tamas, G.; Strom-Tejsena, P.; Hodgson, A.T.; Destaillats, H.; Herrington, J.; Zhang,J.; Nazaroff, W.W.

    2007-07-01

    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 {approx}70 to 130 ppb at the lower air exchange rate and from {approx}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.

  1. Psidium guajava 'Paluma' (the guava plant) as a new bio-indicator of ozone in the tropics.

    PubMed

    Furlan, C M; Moraes, R M; Bulbovas, P; Domingos, M; Salatino, A; Sanz, M J

    2007-06-01

    Psidium guajava 'Paluma' saplings were exposed to carbon filtered air (CF), ambient non-filtered air (NF), and ambient non-filtered air+40ppb ozone (NF+O(3)) 8h per day during two months. The AOT40 values at the end of the experiment were 48, 910 and 12 895ppbh(-1), respectively for the three treatments. After 5 days of exposure (AOT40=1497ppbh(-1)), interveinal red stippling appeared in plants in the NF+O(3) chamber. In the NF chamber, symptoms were observed only after 40 days of exposure (AOT40=880ppbh(-1)). After 60 days, injured leaves per plant corresponded to 86% in NF+O(3) and 25% in the NF treatment, and the average leaf area injured was 45% in NF+O(3) and 5% in the NF treatment. The extent of leaf area injured (leaf injury index) was explained mainly by the accumulated exposure of ozone (r(2)=0.91; p<0.05).

  2. Is There an Arctic Ozone Hole?

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.

    1999-01-01

    Total ozone observations from the Total Ozone Mapping Spectrometer (TOMS) instruments during March 1997 revealed an extensive region of low column densities in the Arctic region centered near the north pole. Values were below 250 Dobson units for nearly a two week period during this period, and were correlated with the position of the northern lower stratospheric polar vortex. The March 1997 average total ozone column densities were more than 30% lower than the average of column densities observed during the 1979-1982 March period. Both the northern spring seasons of 1998 and 1999 have shown much higher levels of total ozone. In this presentation, we will discuss the causes of the low total ozone values in 1997 and contrast those low values with the higher 1998 and 1999 observations. The reason for my travel to the University of Valparaiso is to give this seminar and provide information to my colleagues on our work here at GSFC. The benefit to NASA is to interact with my Univ. of Valparaiso colleagues, gain their insights and input into this research, and establish collaborations with the current research efforts at the University.

  3. Comparison of SBUV and SAGE II ozone profiles: Implications for ozone trends

    NASA Technical Reports Server (NTRS)

    Mcpeters, R. D.; Miles, T.; Flynn, L. E.; Wellemeyer, C. G.; Zawodny, J. M.

    1994-01-01

    Solar backscattered ultraviolet (SBUV) ozone profiles have been compared with Stratospheric Aerosol and Gas Experiment (SAGE) II profiles over the period October 1984 through June 1990, when data are available from both instruments. SBUV measurements were selected to closely match the SAGE II latitude/longitude measurement pattern. There are significant differences between the SAGE II sunrise and the sunset zonal mean ozone profiles in the equatorial zone, particularly in the upper stratosphere, that may be connected with extreme SAGE II solar azimuth angles for tropical sunrise measurements. Calculation of the average sunset bias between SBUV and SAGE II ozone profiles shows that allowing for diurnal variation in Umkehr layer 10, SBUV and SAGE II agree to within +/- 5% for the entire stratosphere in the northern midlatitude zone. The worst agreement is seen at southern midlatitudes near the ozone peak (disagreements of +/- 10%), apparently the result of the SBUV ozone profile peaking at a lower altitude than SAGE. The integrated ozone columns (cumulative above 15 km) agree very well, to within +/- 2.3% in all zones for both sunset and sunrise measurements. A comparison of the time dependence of SBUV and SAGE II shows that there was less than +/- 5% relative drift over the 5.5 years for all altitudes except below 25 km, where the SBUV vertical resolution is poor. The best agreement with SAGE is seen in the integrated column ozone (cumulative above 15 km), where SAGE II has a 1% negative trend relative to SBUV over the comparison period. There is a persistent disagreement of the two instruments in Umkehr layers 9 and 10 of +/- 4% over the 5.5-year comparison period. In the equatorial zone this disagreement may be caused in part by a large positive trend (0.8 K per year) in the National Meteorologica Center temperatures used to convert the SAGE II measurement of ozone density versus altitude to a pressure scale for comparison with SBUV. In the middle stratosphere (30

  4. [Ozone exposure and asthma].

    PubMed

    Kleis, S; Louis, R; Bartsch, P

    2003-03-01

    Ozone is a pollutant the production of which depends on weather conditions and car engine combustion. Numerous epidemiological studies have indicated that high ozone levels correlated with morbidity in asthma. Experimental studies have shown that exposure of healthy subjects and asthmatics to ozone levels comparable to those measured in ambient air during hot summer days can generate respiratory symptoms, neutrophilic airways inflammation and lung function impairment. Lung function changes following ozone exposure are more pronounced in asthmatics and are dependent on the duration and intensity of exposure, a previous exposure and the nutritional status of the subjects. The airway epithelial cell layer is likely to play a pivotal role in initiating the inflammatory process following ozone exposure. Control of ambient air ozone levels must be a target for public health authorities.

  5. Biological effects of ozone

    SciTech Connect

    Lippmann, M. )

    1989-09-01

    Tropospheric ozone, a classic anthropogenic air pollutant, is going to remain a troublesome byproduct of contemporary civilization for many decades. We have known for some time that the hydrocarbons and nitrogen oxides from motor vehicles, together with actinic radiation, account for local and regional photochemistry leading to prolonged afternoon ozone peaks. We also now know that agricultural burning and intensive animal husbandry elevate regional and mesoscale concentrations of ozone and its precursors, and that remote background levels of ozone have been rising steadily throughout this century. The changes we will have to make in emission controls to appreciably reduce current tropospheric ozone levels will have profound effects on our transportation systems, consumer products, and lifestyles. As a society, we will have to make difficult choices about the levels of ozone-associated health, welfare, and natural system damage we will tolerate, or conversely, how much we are willing to pay for controls which can minimize the damage.

  6. Ozone therapy in periodontics

    PubMed Central

    Gupta, G; Mansi, B

    2012-01-01

    Gingival and Periodontal diseases represent a major concern both in dentistry and medicine. The majority of the contributing factors and causes in the etiology of these diseases are reduced or treated with ozone in all its application forms (gas, water, oil). The beneficial biological effects of ozone, its anti-microbial activity, oxidation of bio-molecules precursors and microbial toxins implicated in periodontal diseases and its healing and tissue regeneration properties, make the use of ozone well indicated in all stages of gingival and periodontal diseases. The primary objective of this article is to provide a general review about the clinical applications of ozone in periodontics. The secondary objective is to summarize the available in vitro and in vivo studies in Periodontics in which ozone has been used. This objective would be of importance to future researchers in terms of what has been tried and what the potentials are for the clinical application of ozone in Periodontics. PMID:22574088

  7. The Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.

    1988-01-01

    Processes that may be responsible for the thinning in the ozone layer above the South Pole are described. The chlorine catalytic cycle which destroys ozone is described, as are the major types of reactions that are believed to interfere with this cycle by forming chlorine reservoirs. The suspected contributions of polar stratospheric clouds to these processes are examined. Finally, the possibility that the ozone hole may be due more to a shift in atmospheric dynamics than to chemical destruction is addressed.

  8. Changes in stratospheric ozone.

    PubMed

    Cicerone, R J

    1987-07-01

    The ozone layer in the upper atmosphere is a natural feature of the earth's environment. It performs several important functions, including shielding the earth from damaging solar ultraviolet radiation. Far from being static, ozone concentrations rise and fall under the forces of photochemical production, catalytic chemical destruction, and fluid dynamical transport. Human activities are projected to deplete substantially stratospheric ozone through anthropogenic increases in the global concentrations of key atmospheric chemicals. Human-induced perturbations may be occurring already.

  9. Adsorption air cleaning from ozone.

    PubMed

    Baltrenas, Pranas; Paliulis, Dainius; Vasarevicius, Saulius; Simaitis, Ramutis

    2003-01-01

    Not much has been written about air cleaning from ozone. The aim of this paper was to demonstrate the possibility of adsorption air cleaning from ozone. The second aim was to investigate the dependence of the efficiency of ozone removal from the air on the height of the adsorber layer and on concentrations of ozone, and to obtain empirical formulas for calculating the efficiency of ozone treatment. Equipment for air cleaning from ozone and nitrogen and sulphur dioxides is suggested.

  10. Total ozone trend significance from space time variability of daily Dobson data

    NASA Technical Reports Server (NTRS)

    Wilcox, R. W.

    1981-01-01

    Estimates of standard errors of total ozone time and area means, as derived from ozone's natural temporal and spatial variability and autocorrelation in middle latitudes determined from daily Dobson data are presented. Assessing the significance of apparent total ozone trends is equivalent to assessing the standard error of the means. Standard errors of time averages depend on the temporal variability and correlation of the averaged parameter. Trend detectability is discussed, both for the present network and for satellite measurements.

  11. Depletion of tropospheric ozone associated with mineral dust outbreaks.

    PubMed

    Soler, Ruben; Nicolás, J F; Caballero, S; Yubero, E; Crespo, J

    2016-10-01

    From May to September 2012, ozone reductions associated with 15 Saharan dust outbreaks which occurred between May to September 2012 have been evaluated. The campaign was performed at a mountain station located near the eastern coast of the Iberian Peninsula. The study has two main goals: firstly, to analyze the decreasing gradient of ozone concentration during the course of the Saharan episodes. These gradients vary from 0.2 to 0.6 ppb h(-1) with an average value of 0.39 ppb h(-1). The negative correlation between ozone and coarse particles occurs almost simultaneously. Moreover, although the concentration of coarse particles remained high throughout the episode, the time series shows the saturation of the ozone loss. The highest ozone depletion has been obtained during the last hours of the day, from 18:00 to 23:00 UTC. Outbreaks registered during this campaign have been more intense in this time slot. The second objective is to establish from which coarse particle concentration a significant ozone depletion can be observed and to quantify this reduction. In this regard, it has been confirmed that when the hourly particle concentration recorded during the Saharan dust outbreaks is above the hourly particle median values (N > N-median), the ozone concentration reduction obtained is statistically significant. An average ozone reduction of 5.5 % during Saharan events has been recorded. In certain cases, this percentage can reach values of higher than 15 %. PMID:27376369

  12. 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.

  13. 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.

  14. Nimbus 7 solar backscatter ultraviolet (SBUV) ozone products user's guide

    NASA Technical Reports Server (NTRS)

    Fleig, Albert J.; Mcpeters, R. D.; Bhartia, P. K.; Schlesinger, Barry M.; Cebula, Richard P.; Klenk, K. F.; Taylor, Steven L.; Heath, Donald F.

    1990-01-01

    Three ozone tape products from the Solar Backscatter Ultraviolet (SBUV) experiment aboard Nimbus 7 were archived at the National Space Science Data Center. The experiment measures the fraction of incoming radiation backscattered by the Earth's atmosphere at 12 wavelengths. In-flight measurements were used to monitor changes in the instrument sensitivity. Total column ozone is derived by comparing the measurements with calculations of what would be measured for different total ozone amounts. The altitude distribution is retrieved using an optimum statistical technique for the inversion. The estimated initial error in the absolute scale for total ozone is 2 percent, with a 3 percent drift over 8 years. The profile error depends on latitude and height, smallest at 3 to 10 mbar; the drift increases with increasing altitude. Three tape products are described. The High Density SBUV (HDSBUV) tape contains the final derived products - the total ozone and the vertical ozone profile - as well as much detailed diagnostic information generated during the retrieval process. The Compressed Ozone (CPOZ) tape contains only that subset of HDSBUV information, including total ozone and ozone profiles, considered most useful for scientific studies. The Zonal Means Tape (ZMT) contains daily, weekly, monthly and quarterly averages of the derived quantities over 10 deg latitude zones.

  15. Compressive strength and behavior of 8H C3000/PMR15 woven composite material

    SciTech Connect

    Mirzadeh, F.

    1988-01-01

    Center-notched and unnotched specimens cut from Celion 3000/PMR15 woven composite panels with 60% fiber volume fraction were tested under quasi-static compressive load to failure at room temperature. Micrographic evidence clearly identifies the mode of compressive failure as fiber kinking. Each fiber in the kink fractures because of a combination of compressive and shear stresses. A post-failure mechanism follows the local fiber-bundle failures, which completely deforms the material by large cracks. In center-notched specimens, fiber kinks start from the notch and propagate to some distance from the notch before the post failure takes place. The effect of bundle interactions on stresses and strains was clearly distinguished by comparing the results of the finite-element analysis of a bundle surrounded by other plies to the results of the Moire interferometry on the edge of a laminate. A model introduced incorporated the micromechanical geometry as well as the constituent properties to predict the notched and unnotched compressive strengths of the woven material. For notched-strength predictions, the Average Stress Criterion was used, and the characteristics distance was found to be a function of laminate thickness. Predicted notched and unnotched strengths correlate very well with the experimental results.

  16. A global tropospheric ozone climatology from trajectory-mapped ozone soundings

    NASA Astrophysics Data System (ADS)

    Liu, G.; Liu, J.; Tarasick, D. W.; Fioletov, V. E.; Jin, J. J.; Moeini, O.; Liu, X.; Sioris, C. E.; Osman, M.

    2013-11-01

    A global three-dimensional (i.e. latitude, longitude, altitude) climatology of tropospheric ozone is derived from the ozone sounding record by trajectory mapping. Approximately 52 000 ozonesonde profiles from more than 100 stations worldwide since 1965 are used. The small number of stations results in a sparse geographical distribution. Here, forward and backward trajectory calculations are performed for each sounding to map ozone measurements to a number of other locations, and so to fill in the spatial domain. This is possible because the lifetime of ozone in the troposphere is of the order of weeks. This physically based interpolation method offers obvious advantages over typical statistical interpolation methods. The trajectory-mapped ozone values show reasonable agreement, where they overlap, to the actual soundings, and the patterns produced separately by forward and backward trajectory calculations are similar. Major regional features of the tropospheric ozone distribution are clearly evident in the global maps. An interpolation algorithm based on spherical functions is further used for smoothing and to fill in remaining data gaps. The resulting three-dimensional global tropospheric ozone climatology facilitates visualization and comparison of different years, decades, and seasons, and offers some intriguing insights into the global variation of tropospheric ozone. It will be useful for climate and air quality model initialization and validation, and as an a priori climatology for satellite data retrievals. Further division of the climatology into decadal and annual averages can provide a global view of tropospheric ozone changes, although uncertainties with regard to the performance of older sonde types, as well as more recent variations in operating procedures, need to be taken into account.

  17. Lysozyme is an ozone-sensitive component of alveolar type II cell lamellar bodies.

    PubMed

    Shelley, S A; Paciga, J E; Balis, J U

    1991-06-01

    Exposure of rats to 3 ppm ozone for up to 8 h results in significant changes in lamellar bodies, the surfactant storing organelles of type II cells. We have previously shown that a 14 kDa lamellar body protein is decreased as early as 4 h after the onset of ozone exposure. We have isolated this ozone-sensitive protein from rat lung lamellar bodies and identified it as lysozyme by immunochemical methods, as well as by its amino acid composition, N-terminal amino acid sequence and bacteriolytic activity. Reduced lysozyme activity in isolated lamellar bodies is detected as early as 4 h after the start of ozone exposure. Following an 8 h ozone exposure, the activity does not return to control levels for at least 48 h. Lamellar body lysozyme is expected to be secreted with surfactant phospholipids, thereby contributing to the antimicrobial defense of the alveolar lining layer. The acute lysozyme deficiency seen in ozone-induced oxidant injury may reduce the resistance of the lung to infection.

  18. The impact of decreases in air temperature and increases in ozone on markers of endothelial function in individuals having type-2 diabetes.

    PubMed

    Lanzinger, Stefanie; Breitner, Susanne; Neas, Lucas; Cascio, Wayne; Diaz-Sanchez, David; Hinderliter, Alan; Peters, Annette; Devlin, Robert B; Schneider, Alexandra

    2014-10-01

    Several studies have reported an association between air pollution and endothelial dysfunction, especially in individuals having diabetes. However, very few studies have examined the impact of air temperature on endothelial function. The objective of this analysis was to investigate short-term effects of temperature and ozone on endothelial function in individuals having diabetes. Moreover, we investigated interactive effects between air temperature and air pollution on markers of endothelial function. Between November 2004 and December 2005 flow-mediated dilatation (FMD), nitroglycerin-mediated dilatation (NTGMD) and several blood markers representing endothelial function were measured using brachial artery ultrasound on four consecutive days in 22 individuals with type-2 diabetes mellitus in Chapel Hill, North Carolina (USA). Daily measurements of meteorological parameters, ozone and particulate matter with an aerodynamic diameter ≤2.5 µm (PM2.5) were obtained from fixed monitoring sites. We used additive mixed-models adjusting for time trend, day of the week, relative humidity and barometric pressure to assess temperature and ozone associations with endothelial function. A 1 °C decrease in the 24-h temperature average was associated with a decrease in mean FMD on the same day (-2.2% (95%-confidence interval:[-4.7;0.3%])) and with a delay of one and four days. A temperature decrement also led to an immediate (-1.7%[-3.3;-0.04]) decrease in NTGMD. Moreover, we observed an immediate (-14.6%[-26.3;-2.9%]) and a one day delayed (-13.5%[-27.0; 0.04%]) decrease in FMD in association with a 0.01 ppm increase in the maximum 8-h moving average of ozone. Temperature effects on FMD strengthened when PM2.5 and ozone concentrations were high. The associations were similar during winter and summer. We detected an association between temperature decreases and ozone increases on endothelial dysfunction in individuals having diabetes. We conclude that endothelial dysfunction

  19. Lidar measurements of stratospheric ozone during the STOIC campaign

    NASA Astrophysics Data System (ADS)

    McGee, Thomas J.; Ferrare, Richard A.; Whiteman, David N.; Butler, James J.; Burris, John F.; Owens, Melody A.

    1995-05-01

    The NASA Goddard Space Flight Center's Stratospheric Ozone Lidar Trailer Experiment participated in the Stratospheric Ozone Intercomparison Campaign (STOIC) at Table Mountain, California, from July 20 to August 2, 1989. From 20 to 39 km the average Goddard Space Flight Center (GSFC) profile agreed with the STOIC reference profile to better than 5%. The STOIC reference profile was generated by averaging all profiles from the eight participating instruments. In this same altitude region the GSFC and the Jet Propulsion Laboratory lidar average profiles also agreed to better than 5%. Similar results were found for an intercomparison of the lidar data with ozone data from ECC sondes launched from Table Mountain and from San Nicholas Island. The results of the intercomparison have led to a number of modifications to the GSFC lidar which have greatly improved the reliability of the ozone data, particularly at altitudes below 20 km and above 40 km.

  20. Lidar measurements of stratospheric ozone during the STOIC campaign

    SciTech Connect

    McGee, T.J.; Burris, J.F.; Ferrare, R.A.

    1995-05-20

    The NASA Goddard Space Flight Center`s Stratospheric Ozone Lidar Trailer Experiment participated in the Stratospheric Ozone Intercomparison Campaign (STOIC) at Table Mountain, California, from July 20 to August 2, 1989. From 20 to 39 km the average Goddard Space Flight Center (GSFC) profile agreed with the STOIC reference profile to better than 5%. The STOIC reference profile was generated by averaging all profiles from the eight participating instruments. In this same altitude region the GSFC and the Jet Propulsion Laboratory lidar average profiles also agreed to better than 5%. Similar results were found for an intercomparison of the lidar data with ozone data from EC sondes launched from Table Mountain and from San Nicholas Island. The results of the intercomparison have led to a number of modifications to the GSFC lidar which have greatly improved the reliability of the ozone data, particularly at altitudes below 20 km and above 40 km. 10 refs., 9 figs.

  1. Occurrence of ozone as a phytotoxicant in Kiev, Ukraine and in the Ukrainian Carpathian mountains

    SciTech Connect

    Bytnerowicz, A.; Manning, W.; Blum, O.; Popovicheva, L.

    1995-12-31

    Ogawa passive ozone samplers were established at the Central Botanic Garden in Kiev and in five forest locations in the Ukrainian Carpathian mountains in summer, 1995. An active ozone monitor (Thermo-Electron 49) was also established at the Botanic Garden, together with plants of ozone-sensitive (Bel-W3) and ozone-tolerant (Bel-B) tobacco (Nicotiana tabacum). The highest average hourly ozone concentration monitored in Kiev was 84.4 ppb. From August to September, two-week average concentrations of ozone (Ogawa samplers) in the Carpathian forests ranged from 27.4--51.8 ppb. During a two-week exposure period, Bel-W3 tobacco plants in Kiev had foliar injury on leaf one as high as 62%, with only 13% for Bel-B. Ozone injury was found on a variety of indicator plants in Kiev and at three of the five passive sampler sites in the Carpathians.

  2. Biomonitoring of tropospheric ozone phytotoxicity in rural Catalonia

    NASA Astrophysics Data System (ADS)

    Ribas, Angela; Peñuelas, Josep

    The ozone (O 3) phytotoxicity in rural areas of Catalonia (NE Spain) and the biomonitoring capacity of Bel-W3 tobacco ( Nicotiana tabacum) cultivars were assessed by determining the percentage of leaf area injured by ozone in plants of this cultivar exposed from spring to autumn since 1995-1999. The study was conducted simultaneously on nine field sites where ground level ozone concentrations and meteorological parameters were continuously monitored. Geographical, seasonal and annual variations of ozone damage rate and their links with meteorological conditions were studied. Ozone concentrations and leaf damage increased at the end of spring and the beginning of summer. Coastal sites generally presented higher O 3 concentrations than inland and mountain sites. These mountain sites were the most sensitive ones to ozone toxicity. The ozone concentrations correlated well with ozone injury. However, at this local scale the ozone levels did not fully account for all the observed injury (only 11%). The response of tobacco plants to ozone concentrations and therefore its biomonitoring capacity depended also on different environmental conditions, mainly those linked to stomatal behaviour such as vapour pressure deficit. The categorization of leaf damage in 10% intervals and its averaging throughout the whole study period and the whole region, strongly improved (99% of variance accounted) the relationship with ozone concentrations expressed as AOT20 (accumulated over a cut-off of 20 ppb v). N. tabacum cultivar Bel-W3 is thus a very good biomonitor of ozone concentrations in the long term at the regional scale. Taking into account the phytotoxical response of this sensitive tobacco cultivar, we propose the 1.28 ppm v h biweekly AOT40 (with a solar radiation threshold of 50 W m -2) as a damage threshold level for sensitive species.

  3. Results of ozone measurements in Northern Germany: A case study

    NASA Technical Reports Server (NTRS)

    Schmidt, Manfred

    1994-01-01

    At most of the German ozone recording stations which have records over a sufficiently long period, the results of the summer months of 1989 showed the highest values since the beginning of the measurements. One of the reasons for this phenomenon was the high duration of sunshine in that summer; for example, in Potsdam near Berlin in May 1989 the sunshine duration was the highest in May since the beginning of the records in 1893. For that reason we selected this summer for a case study. The basis for the study was mainly the ozone measuring stations of the network of Lower Saxony and the Federal Office of Environment (Umweltbundesamt). The results of these summer measurements point to intense sources of ozone, probably in form of gaseous precursors, in the Middle German industrial areas near Leipzig and Halle and in Northwestern Czechoslovakia, with coal-mining, chemical and petrochemical industries, coking plants and others. The maps of average ozone concentrations, number or days with high ozone maxima, ozone-windroses of the stations, etc., suggest that these areas could be a main source of precursors and of photochemical ozone production in summer smog episodes in Central Europe. Stations on the North Sea coast, at which early ozone measurements were made by our institute in 1973/74 are compared with similarly located stations of the Lower Saxon network in 1989 and the results show a reversal of the ozone-windroses. In 1973/74, the highest ozone concentrations were correlated with wind directions from the sea while in 1989 these concentrations were correlated with directions from the continent. In the recent years, photochemical ozone production on the continent is probably predominant, while in former years the higher ozone content of the maritime subpolar air masses has been explained by stratospheric-tropospheric exchange.

  4. Volumetric Properties of the Mixture Heptane C7H16 + C8H16 Cyclooctane (VMSD1242, LB3830_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Heptane C7H16 + C8H16 Cyclooctane (VMSD1242, LB3830_V)' providing data by calculation of molar excess volume from density measurements at variable pressure and constant temperature and mole fraction.

  5. Volumetric Properties of the Mixture Tetrachloromethane CCl4 + C8H16 Cyclooctane (VMSD1211, LB3564_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Tetrachloromethane CCl4 + C8H16 Cyclooctane (VMSD1211, LB3564_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  6. Volumetric Properties of the Mixture Cyclooctane C8H16 + C16H34 Hexadecane (VMSD1141, LB3790_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclooctane C8H16 + C16H34 Hexadecane (VMSD1141, LB3790_V)' providing data from direct measurement of mass density at variable pressure and constant temperature and mole fraction.

  7. Volumetric Properties of the Mixture Hexane C6H14 + C8H16 Cyclooctane (VMSD1242, LB3843_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Hexane C6H14 + C8H16 Cyclooctane (VMSD1242, LB3843_V)' providing data by calculation of molar excess volume from density measurements at variable pressure and constant temperature and mole fraction.

  8. Volumetric Properties of the Mixture Cyclooctane C8H16 + C10H22 Decane (VMSD1141, LB3788_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclooctane C8H16 + C10H22 Decane (VMSD1141, LB3788_V)' providing data from direct measurement of mass density at variable pressure and constant temperature and mole fraction.

  9. Volumetric Properties of the Mixture Cyclooctane C8H16 + C10H22 Decane (VMSD1242, LB3844_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclooctane C8H16 + C10H22 Decane (VMSD1242, LB3844_V)' providing data by calculation of molar excess volume from density measurements at variable pressure and constant temperature and mole fraction.

  10. Volumetric Properties of the Mixture Hexane C6H14 + C8H16 Cyclooctane (VMSD1141, LB3786_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Hexane C6H14 + C8H16 Cyclooctane (VMSD1141, LB3786_V)' providing data from direct measurement of mass density at variable pressure and constant temperature and mole fraction.

  11. Volumetric Properties of the Mixture Heptane C7H16 + C8H16 Cyclooctane (VMSD1141, LB3787_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Heptane C7H16 + C8H16 Cyclooctane (VMSD1141, LB3787_V)' providing data from direct measurement of mass density at variable pressure and constant temperature and mole fraction.

  12. Volumetric Properties of the Mixture Cyclooctane C8H16 + C16H34 Hexadecane (VMSD1242, LB3836_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclooctane C8H16 + C16H34 Hexadecane (VMSD1242, LB3836_V)' providing data by calculation of molar excess volume from density measurements at variable pressure and constant temperature and mole fraction.

  13. Volumetric Properties of the Mixture Cyclooctane C8H16 + C14H30 Tetradecane (VMSD1141, LB3789_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclooctane C8H16 + C14H30 Tetradecane (VMSD1141, LB3789_V)' providing data from direct measurement of mass density at variable pressure and constant temperature and mole fraction.

  14. Heat of Mixing and Solution of Tetrachloromethane CCl4 + C8H16 Cyclooctane (HMSD1111, LB4087_H)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Heat of Mixing and Solution of Tetrachloromethane CCl4 + C8H16 Cyclooctane (HMSD1111, LB4087_H)' providing data from direct low-pressure calorimetric measurement of molar excess enthalpy at variable mole fraction and constant temperature.

  15. Volumetric Properties of the Mixture Cyclooctane C8H16 + C12H22 Bicyclohexyl (VMSD1211, LB3529_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclooctane C8H16 + C12H22 Bicyclohexyl (VMSD1211, LB3529_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  16. Volumetric Properties of the Mixture Pentane C5H12 + C8H16 Cyclooctane (VMSD1242, LB3842_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Pentane C5H12 + C8H16 Cyclooctane (VMSD1242, LB3842_V)' providing data by calculation of molar excess volume from density measurements at variable pressure and constant temperature and mole fraction.

  17. Volumetric Properties of the Mixture Cyclooctane C8H16 + C14H30 Tetradecane (VMSD1242, LB3829_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclooctane C8H16 + C14H30 Tetradecane (VMSD1242, LB3829_V)' providing data by calculation of molar excess volume from density measurements at variable pressure and constant temperature and mole fraction.

  18. Volumetric Properties of the Mixture Pentane C5H12 + C8H16 Cyclooctane (VMSD1141, LB3785_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Pentane C5H12 + C8H16 Cyclooctane (VMSD1141, LB3785_V)' providing data from direct measurement of mass density at variable pressure and constant temperature and mole fraction.

  19. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C8H16 Cyclooctane (VMSD1211, LB3565_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C8H16 Cyclooctane (VMSD1211, LB3565_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  20. Nqrs Data for C8H8Cl3N3O4S2 (Subst. No. 1087)

    NASA Astrophysics Data System (ADS)

    Chihara, H.; Nakamura, N.

    This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C8H8Cl3N3O4S2 (Subst. No. 1087)

  1. Dynamics of the reaction of C{sub 2} with C{sub 6}H{sub 2}: An implication for the formation of interstellar C{sub 8}H

    SciTech Connect

    Sun, Yi-Lun; Huang, Wen-Jian; Chin, Chih-Hao; Lee, Shih-Huang

    2014-11-21

    The reaction C{sub 2} + C{sub 6}H{sub 2} → C{sub 8}H + H was investigated for the first time. Reactant C{sub 2} (C{sub 6}H{sub 2}) was synthesized from 1% C{sub 3}F{sub 6}/He (5% C{sub 2}H{sub 2}/He) by pulsed high-voltage discharge. We measured the translational-energy distribution, the angular distribution, and the photoionization spectrum of product C{sub 8}H in a crossed molecular-beam apparatus using synchrotron vacuum-ultraviolet ionization. This reaction released average translational energy of 8.5 kcal mol{sup −1} corresponding to a fraction of 0.37 in translation. C{sub 8}H was identified as octatetranyl based on the maximal translational-energy release 23 ± 2 kcal mol{sup −1} and the ionization threshold 8.9 ± 0.2 eV. Kinematic constraints can qualitatively account for the nearly isotropic angular distribution. The quantum-chemical calculations indicate that the exothermic reactions C{sub 2} (X {sup 1}Σ{sub g}{sup +}/a {sup 3}Π{sub u}) + HC{sub 6}H → C{sub 8}H + H can proceed without entrance and exit barriers, implying the importance in the cold interstellar medium. This work verifies that interstellar C{sub 8}H can be formed through the C{sub 2} + C{sub 6}H{sub 2} reaction.

  2. Ozone impacts of natural gas development in the Haynesville Shale.

    PubMed

    Kemball-Cook, Susan; Bar-Ilan, Amnon; Grant, John; Parker, Lynsey; Jung, Jaegun; Santamaria, Wilson; Mathews, Jim; Yarwood, Greg

    2010-12-15

    The Haynesville Shale is a subsurface rock formation located beneath the Northeast Texas/Northwest Louisiana border near Shreveport. This formation is estimated to contain very large recoverable reserves of natural gas, and during the two years since the drilling of the first highly productive wells in 2008, has been the focus of intensive leasing and exploration activity. The development of natural gas resources within the Haynesville Shale is likely to be economically important but may also generate significant emissions of ozone precursors. Using well production data from state regulatory agencies and a review of the available literature, projections of future year Haynesville Shale natural gas production were derived for 2009-2020 for three scenarios corresponding to limited, moderate, and aggressive development. These production estimates were then used to develop an emission inventory for each of the three scenarios. Photochemical modeling of the year 2012 showed increases in 2012 8-h ozone design values of up to 5 ppb within Northeast Texas and Northwest Louisiana resulting from development in the Haynesville Shale. Ozone increases due to Haynesville Shale emissions can affect regions outside Northeast Texas and Northwest Louisiana due to ozone transport. This study evaluates only near-term ozone impacts, but the emission inventory projections indicate that Haynesville emissions may be expected to increase through 2020.

  3. Ozone impacts of natural gas development in the Haynesville Shale.

    PubMed

    Kemball-Cook, Susan; Bar-Ilan, Amnon; Grant, John; Parker, Lynsey; Jung, Jaegun; Santamaria, Wilson; Mathews, Jim; Yarwood, Greg

    2010-12-15

    The Haynesville Shale is a subsurface rock formation located beneath the Northeast Texas/Northwest Louisiana border near Shreveport. This formation is estimated to contain very large recoverable reserves of natural gas, and during the two years since the drilling of the first highly productive wells in 2008, has been the focus of intensive leasing and exploration activity. The development of natural gas resources within the Haynesville Shale is likely to be economically important but may also generate significant emissions of ozone precursors. Using well production data from state regulatory agencies and a review of the available literature, projections of future year Haynesville Shale natural gas production were derived for 2009-2020 for three scenarios corresponding to limited, moderate, and aggressive development. These production estimates were then used to develop an emission inventory for each of the three scenarios. Photochemical modeling of the year 2012 showed increases in 2012 8-h ozone design values of up to 5 ppb within Northeast Texas and Northwest Louisiana resulting from development in the Haynesville Shale. Ozone increases due to Haynesville Shale emissions can affect regions outside Northeast Texas and Northwest Louisiana due to ozone transport. This study evaluates only near-term ozone impacts, but the emission inventory projections indicate that Haynesville emissions may be expected to increase through 2020. PMID:21086985

  4. Impacts of Global Climate Change and Emissions on Regional Ozone and Fine Particulate Matter Concentrations over United States

    SciTech Connect

    Tagaris, Efthimios; Manomaiphiboon, Kasemsan; Liao, Kuo-Jen; Leung, Lai R.; Woo, Jung-Hun; He, Shan; Amar, Praveen; Russell, Armistead G.

    2007-07-31

    Simulated future summers (i.e., 2049-2051) and annual (i.e., 2050) average regional O 3 and PM2.5 concentrations over North America are compared with historic (i.e., 2000-2002 summers and all of 2001) levels to investigate the potential impacts of global climate change on regional air quality. Meteorological inputs to the CMAQ chemical transport model are developed by downscaling the GISS Global Climate Model simulations using an MM5-based regional climate model. Future-year emissions for North America are developed by growing the US EPA CAIR inventory, Mexican and Canadian emissions and by using the IMAGE model with the IPCC A1B emissions scenario that is also used in projecting future climate. Reductions of more than 50% in NOX and SO2 emissions are forecast. The impacts of global climate change alone on regional air quality are small compared to impacts from emission control-related reductions in the US and Canada. The combined effect of climate change and emission reductions lead to a 20% decrease (regionally varying from -11% to -28% regionally) in the mean summer maximum daily 8-hr ozone levels (M8hO3) over the US, -8% over Canada and -10% over Northern Mexico. The mean annual PM2.5 concentrations are estimated to be 23% lower (varies from -9% to -32%) over the US, -7% and -15% over Western and Eastern Canada, respectively and -25% over Northern Mexico. Major reductions are expected in sulfate, nitrate and ammonium fractions of annually-averaged PM2.5 for all sub-regions. The limited reduction in organic carbon over the US and Northern Mexico and the higher concentrations over Canada suggests that organic carbon will be the dominant component of PM2.5 mass over most of the continent in the future. Regionally, the Eastern US benefits more than the rest of the regions from reductions in both M8hO3 and PM2.5, due to both spatial variations in the meteorological and emissions changes. Reduction in the higher M8hO3 concentrations is also estimated for all sub

  5. Tropospheric ozone in the Nisqually River Drainage, Mount Rainier National Park

    USGS Publications Warehouse

    Peterson, D.L.; Bowers, Darci

    1999-01-01

    We quantified the summertime distribution of tropospheric ozone in the topographically complex Nisqually River drainage of Mount Rainier National Park from 1994 to 1997. Passive ozone samplers were used along an elevational transect to measure weekly average ozone concentrations ranging from 570 m to 2040 m elevation. Weekly average ozone concentrations were positively correlated with elevation, with the highest concentrations consistently measured at the highest sampling site (Panorama Point). Weekly average ozone concentrations at Mount Rainier National Park are considerably higher than those in the Seattle-Tacoma metropolitan area to the west. The anthropogenic contribution to ozone within the Nisqually drainage was evaluated by comparing measurements at this location with measurements from a 'reference' site in the western Olympic Mountains. The comparison suggests there is a significant anthropogenic source of ozone reaching the Cascade Range via atmospheric transport from urban areas to the west. In addition. temporal (week to week) variation in ozone distribution is synchronous within the Nisqually drainage, which indicates that subregional patterns are detectable with weekly averages. The Nisqually drainage is likely the 'hot spot' for air pollution in Mount Rainier National Park. By using passive ozone samplers in this drainage in conjunction with a limited number of continuous analyzers, the park will have a robust monitoring approach for measuring tropospheric ozone over time and protecting vegetative and human health.

  6. The Antarctic Ozone Hole.

    ERIC Educational Resources Information Center

    Stolarski, Richard S.

    1988-01-01

    Discusses the Airborne Antarctic Ozone Experiment (1987) and the findings of the British Antarctic Survey (1985). Proposes two theories for the appearance of the hole in the ozone layer over Antarctica which appears each spring; air pollution and natural atmospheric shifts. Illustrates the mechanics of both. Supports worldwide chlorofluorocarbon…

  7. Surface Ozone in Kiev

    NASA Astrophysics Data System (ADS)

    Shavrina, A. V.; Mikulskaya, I. A.; Kiforenko, S. I.; Blum, O. B.; Sheminova, V. A.; Veles, A. A.

    The study of total ozone over Kiev and its concentration changes with height in the troposphere has been made on the base of ground-based observations with the infrared Fourier-spectrometer in the Main Astronomical Observatory of National Academy of Sciences of Ukraine (MAO NASU) as part of ESA-NIVR-KNMI project no 2907 "OMI validation by ground based remote sensing: ozone columns and atmospheric profiles "(2005-2008) [1,2,4]. Ground-level ozone in Kiev for an episode of its high concentrations in August 2000 was also simulated with the model of urban air pollution UAM-V [5,6]. In 2008 the satellite data Aura-OMI on profiles of ozone in the atmosphere OMO3PR became available (http://disc.sci.gsfc.nasa.gov/ Aura/data-holdings/OMI/ omo3pr_v003.shtml). They include ozone content in the lower layer of the atmosphere, beginning from 2005, which can be used to evaluate the ground-level ozone in all cities of Ukraine. The comparison of the data of ozone air pollution in Kiev (ozone - the pollutant of the first class of danger) and medical statistics data of of respiratory system (RS) diseases of the city population was carried out with the package "Statistica". A regression analysis, prognostic regression modelling, and retrospective prognosis of the epidemiological situation with respect to RS pathologies in Kiev in 2000-2006 were performed.

  8. Ozone and temperature trends

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.; Fioletov, Vitali; Bishop, Lane; Godin, Sophie; Bojkov, Rumen D.; Kirchhoff, Volker; Chanin, Marie-Lise; Zawodny, Joseph M.; Zerefos, Christos S.; Chu, William

    1991-01-01

    An update of the extensive reviews of the state of knowledge of measured ozone trends published in the Report of the International Ozone Trends Panel is presented. The update contains a review of progress since these reports, including reviewing of the ozone records, in most cases through March 1991. Also included are some new, unpublished reanalyses of these records including a complete reevaluation of 29 stations located in the former Soviet Union. The major new advance in knowledge of the measured ozone trend is the existence of independently calibrated satellite data records from the Total Ozone Mapping Spectrometer (TOMS) and Stratospheric Aerosol and Gas Experiment (SAG) instruments. These confirm many of the findings, originally derived from the Dobson record, concerning northern mid-latitude changes in ozone. We now have results from several instruments, whereas the previously reported changes were dependent on the calibration of a single instrument. This update will compare the ozone records from many different instruments to determine whether or not they provide a consistent picture of the ozone change that has occurred in the atmosphere. The update also briefly considers the problem of stratospheric temperature change. As in previous reports, this problem received significantly less attention, and the report is not nearly as complete. This area needs more attention in the future.

  9. Saving Our Ozone Shield.

    ERIC Educational Resources Information Center

    Lacoste, Beatrice

    1992-01-01

    Discusses the introduction and continued use of chlorofluorocarbons (CFCs) as related to stratospheric ozone depletion. Presents the characteristics of CFCs conducive to the chemical reaction with ozone, the history of CFC use and detection of related environmental problems, health hazards, and alternatives to CFC use. (MCO)

  10. Polar Ozone Workshop. Abstracts

    NASA Technical Reports Server (NTRS)

    Aikin, Arthur C.

    1988-01-01

    Results of the proceedings of the Polar Ozone Workshop held in Snowmass, CO, on May 9 to 13, 1988 are given. Topics covered include ozone depletion, ozonometry, polar meteorology, polar stratospheric clouds, remote sensing of trace gases, atmospheric chemistry and dynamical simulations.

  11. Houston’s rapid ozone increases: preconditions and geographic origins

    PubMed Central

    Couzo, Evan; Jeffries, Harvey E.; Vizuete, William

    2013-01-01

    Many of Houston’s highest 8-h ozone (O3) peaks are characterised by increases in concentrations of at least 40 ppb in 1 h, or 60 ppb in 2 h. These rapid increases are called non-typical O3 changes (NTOCs). In 2004, the Texas Commission on Environmental Quality (TCEQ) developed a novel emissions control strategy aimed at eliminating NTOCs. The strategy limited routine and short-term emissions of ethene, propene, 1,3-butadiene and butene isomers, collectively called highly reactive volatile organic compounds (HRVOCs), which are released from petrochemical facilities. HRVOCs have been associated with NTOCs through field campaigns and modelling studies. This study analysed wind measurements and O3, formaldehyde (HCHO) and sulfur dioxide (SO2) concentrations from 2000 to 2011 at 25 ground monitors in Houston. NTOCs almost always occurred when monitors were downwind of petrochemical facilities. Rapid O3 increases were associated with low wind speeds; 75 % of NTOCs occurred when the 3-h average wind speed preceding the event was less than 6.5 km h−1. Statistically significant differences in HCHO concentrations were seen between days with and without NTOCs. Early afternoon HCHO concentrations were greater on NTOC days. In the morning before an observed NTOC event, however, there were no significant differences in HCHO concentrations between days with and without NTOCs. Hourly SO2 concentrations also increased rapidly, exhibiting behaviour similar to NTOCs. Oftentimes, the SO2 increases preceded a NTOC. These findings show that, despite the apparent success of targeted HRVOC emission controls, further restrictions may be needed to eliminate the remaining O3 events. PMID:24014080

  12. Spatiotemporal modelling of ozone distribution in the State of California

    NASA Astrophysics Data System (ADS)

    Bogaert, P.; Christakos, G.; Jerrett, M.; Yu, H.-L.

    This paper is concerned with the spatiotemporal mapping of monthly 8-h average ozone ( O3) concentrations over California during a 15-years period. The basic methodology of our analysis is based on the spatiotemporal random field (S/TRF) theory. We use a S/TRF decomposition model with a dominant seasonal O3 component that may change significantly from site to site. O3 seasonal patterns are estimated and separated from stochastic fluctuations. By means of Bayesian Maximum Entropy (BME) analysis, physically meaningful and sufficiently detailed space-time maps of the seasonal O3 patterns are generated across space and time. During the summer and winter months the seasonal O3 concentration maps exhibit clear and progressively changing geographical patterns over time, suggesting the existence of relationships in accordance with the typical physiographic and climatologic features of California. BME mapping accuracy can be superior to that of other techniques commonly used by EPA; its framework can rigorously assimilate useful data sources that were previously unaccounted for; the generated maps offer valuable assessments of the spatiotemporal O3 patterns that can be helpful in the identification of physical mechanisms and their interrelations, the design of human exposure and population health models, and in risk assessment. As they focus on the seasonal patterns, the maps are not contingent on short-time and locally prevalent weather conditions, which are of no interest in a global and non-forecasting framework. Moreover, the maps offer valuable insight about the space-time O3 concentration patterns and are, thus, helpful for disentangling the influence of explanatory factors or even for identifying some influential ones that could have been otherwise overlooked.

  13. The average enzyme principle.

    PubMed

    Reznik, Ed; Chaudhary, Osman; Segrè, Daniel

    2013-09-01

    The Michaelis-Menten equation for an irreversible enzymatic reaction depends linearly on the enzyme concentration. Even if the enzyme concentration changes in time, this linearity implies that the amount of substrate depleted during a given time interval depends only on the average enzyme concentration. Here, we use a time re-scaling approach to generalize this result to a broad category of multi-reaction systems, whose constituent enzymes have the same dependence on time, e.g. they belong to the same regulon. This "average enzyme principle" provides a natural methodology for jointly studying metabolism and its regulation.

  14. Observing trends in total ozone and extreme ozone events

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2014-05-01

    The ozone layer in the stratosphere has been recovering since the 1989 Montreal Protocol reduced the use of ozone-destroying chlorofluorocarbons. Fitzka et al. observed trends in total ozone levels and the vertical distribution of ozone at Hoher Sonnblick, a mountain in Austria, from 1994 to 2011.

  15. Distinctive timing of U.S. historical ozone change determined by climate and anthropogenic emissions

    NASA Astrophysics Data System (ADS)

    Yan, Y.; Lin, J.; He, C.

    2015-12-01

    The ground-level ozone over the United States is known to have been influenced by historical climate change and anthropogenic precursor emissions, whereas their individual contributions and the associated mechanisms of influence remain less understood. Here we analyze 25-year (1990-2014) annual mean ground-level ozone across the U.S. Empirical Orthogonal Function (EOF) and linear fitting show that ozone has experienced a notable rate of growth at 0.13 ppb/yr averaged over U.S. About 74% of this growth is attributed to enhancement in nighttime ozone (at 0.19 ppb/yr), with the remaining 26% due to daytime ozone increase (at 0.07 ppb/yr). To relate ozone interannual variations to climate change, we employ the Atlantic Multi-decadal Oscillation (AMO) and Southern Oscillation (SO) indices to infer the states of climate over the U.S. We find large correlations between ozone interannual variability and these climate indices: 0.65 for SO index, 0.73 for AMO index, and 0.82 for their combined index. The correlations are much higher (0.69, 0.78 and 0.86) for daytime ozone. Sensitivity simulations conducted with the GEOS-Chem chemical transport model reveal that climate variability has determined ozone interannual variability, particularly for daytime ozone, while anthropogenic emissions reductions have particularly driven the growth in nighttime ozone. These results better connect ozone air pollution with human activity and climate change. Figure. Slopes for the linear fitting analyse of the ground-level ozone variations on the inter-annual timescale for AQS measurements during 1990-2014 (a) for daytime ozone and (b) for nighttime ozone. Also shown are the slopes for interannual variation during 2004-2011 (c) for daytime ozone and (d) for nighttime ozone.

  16. Climate-chemistry interaction affecting tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Mao, Huiting

    1999-09-01

    Tropospheric ozone, an important radiative-chemical species, has been observed increasing especially at northern midlatitudes during the past few decades. This dissertation addresses climate-chemistry interaction associated with such increases in three aspects using observations as well as atmospheric chemistry and climate models. Ozone impact on climate is first evaluated by radiative forcing calculations due to observed ozone changes. It is found that a 10% increase in tropospheric ozone causes a radiative forcing of 0.17 Wm-2 using a fixed temperature (FT) method or 0.13 Wm-2 using a fixed dynamic heating (FDH) method, which is comparable to the radiative forcing 0.26 (FT) and -0.09 Wm-2 (FDH) caused by the stratospheric ozone depletion during the 1980s. Second, radiative forcing due to changes in ozone precursors is estimated. Ozone changes in response to a 20% reduction in surface NOx emission in six regions around the globe differ between regions. A maximum decrease in ozone column reaches 5% in southeast Asia and the central Atlantic Ocean, inducing a local radiative forcing of up to -0.1 Wm-2 in those regions. It indicates that surface NOx emission changes can potentially affect regional climate. Third, the effects of climate and climate changes on atmospheric chemistry are addressed with two studies. One study investigates the effects of global warming on methane and ozone, and another looks into cloud effects on photodissociation rate constants. Calculations based on the IPCC business-as-usual scenario indicate that by 2050, temperature and moisture increases can suppress methane and tropospheric ozone increases by 17% and 11%, respectively, in reference to the 1990 concentrations. The combined effects offset the global warming induced forcing 3.90 Wm -2 by -0.46 Wm-2. A one-dimensional study suggests that a typical cirrus cloud (τ = 2) can significantly increase J(O1D) and J(NO2) around the tropopause with a maximum of 21%. Geographical and seasonal

  17. Ozone in equatorial latitudes

    NASA Astrophysics Data System (ADS)

    Martini, L.; Zimmermann, G.; Trinkkeller, B.

    The presence of ozone in the atmosphere protects the biosphere against harmful solar UV radiation. The ozone distribution in the atmosphere is maintained on the basis of a complex system of reactions. The amount of atmospheric ozone might be reduced as a consequence of human activities. Such reduction in the atmospheric ozone could affect climate and biological processes on earth. As a part of plans for a further enhancement of the global surveillance of the atmospheric ozone layer, a series of radiation experiments concerning the quartz-ultraviolet region were conducted as a joint project of the German Democratic Republic and the USSR. The experiments had the objective to measure the radiative flux of the solar UV radiation and to determine absorption and dispersion of the radiation in the upper atmosphere. The investigation included the launching of 12 rockets from a research vessel in the Indian Ocean near the equator and 34 balloon flights.

  18. Effect of ozone and histamine on airway permeability to horseradish peroxidase in guinea pigs

    SciTech Connect

    Miller, P.D.; Gordon, T.; Warnick, M.; Amdur, M.O.

    1986-01-01

    Airway permeability was studied in groups of male guinea pigs at 2, 8, and 24 h after a 1-h exposure to 1 ppm ozone or at 2 h after a 1-h exposure to filtered air (control). Intratracheal administration of 2 mg horseradish peroxidase (HRP) was followed by blood sampling at 5-min intervals up to 30 min. The rate of appearance of HRP in plasma was significantly higher at 2 and 8 h after ozone exposure than that found in animals examined 2 h after air exposure or 24 h after ozone exposure. A dose of 0.12 mg/kg of subcutaneous histamine given after the 15 min blood sample significantly increased the already elevated permeability seen at 2 h post ozone, but had no effect on animals exposed to filtered air 2 h earlier or to ozone 24 h earlier. No difference was seen in the amount of subcutaneous radiolabeled histamine in the lungs of animals exposed 2 h earlier either to air or to ozone. These data indicate that a short-term exposure to ozone produced a reversible increase in respiratory epithelial permeability to HRP in guinea pigs. The potentiation of this increased permeability by histamine may be another manifestation of ozone-induced hyperreactivity.

  19. Diurnal variations of stratospheric ozone measured by ground-based microwave remote sensing at the Mauna Loa NDACC site: measurement validation and GEOSCCM model comparison

    NASA Astrophysics Data System (ADS)

    Parrish, A.; Boyd, I. S.; Nedoluha, G. E.; Bhartia, P. K.; Frith, S. M.; Kramarova, N. A.; Connor, B. J.; Bodeker, G. E.; Froidevaux, L.; Shiotani, M.; Sakazaki, T.

    2014-07-01

    There is presently renewed interest in diurnal variations of stratospheric and mesospheric ozone for the purpose of supporting homogenization of records of various ozone measurements that are limited by the technique employed to being made at certain times of day. We have made such measurements for 19 years using a passive microwave remote sensing technique at the Mauna Loa Observatory (MLO) in Hawaii, which is a primary station in the Network for Detection of Atmospheric Composition Change (NDACC). We have recently reprocessed these data with hourly time resolution to study diurnal variations. We inspected differences between pairs of the ozone spectra (e.g., day and night) from which the ozone profiles are derived to determine the extent to which they may be contaminated by diurnally varying systematic instrumental or measurement effects. These are small, and we have reduced them further by selecting data that meet certain criteria that we established. We have calculated differences between profiles measured at different times: morning-night, afternoon-night, and morning-afternoon and have intercompared these with like profiles derived from the Aura Microwave Limb Sounder (Aura-MLS), the Upper Atmosphere Research Satellite Microwave Limb Sounder (UARS-MLS), the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES), and Solar Backscatter Ultraviolet version 2 (SBUV/2) measurements. Differences between averages of coincident profiles are typically < 1.5% of typical nighttime values over most of the covered altitude range with some exceptions. We calculated averages of ozone values for each hour from the Mauna Loa microwave data, and normalized these to the average for the first hour after midnight for comparison with corresponding values calculated with the Goddard Earth Observing System Chemistry Climate Model (GEOSCCM). We found that the measurements and model output mostly agree to better than 1.5% of the midnight value, with one noteworthy exception

  20. Reconciling NOx emissions reductions and ozone trends in the U.S., 2002-2006

    NASA Astrophysics Data System (ADS)

    Zhou, Wei; Cohan, Daniel S.; Napelenok, Sergey L.

    2013-05-01

    Dynamic evaluation seeks to assess the ability of photochemical models to replicate changes in air quality as emissions and other conditions change. When a model fails to replicate an observed change, a key challenge is to discern whether the discrepancy is caused by errors in meteorological simulations, errors in emission magnitudes and changes, or inaccurate responses of simulated pollutant concentrations to emission changes. In this study, the Community Multiscale Air Quality (CMAQ) model is applied to simulate the ozone (O3) change after the NOx SIP Call and mobile emission controls substantially reduced nitrogen oxides (NOx) emissions in the eastern U.S. from 2002 to 2006. For both modeled and observed O3, changes in episode average daily maximal 8-h O3 were highly correlated (R2 = 0.89) with changes in the 95th percentile, although the magnitudes of reductions increased nonlinearly at high percentile O3 concentrations. Observed downward changes in mean NOx (-11.6 to -2.5 ppb) and 8-h O3 (-10.4 to -4.7 ppb) concentrations in metropolitan areas in the NOx SIP Call region were under-predicted by 31%-64% and 26%-66%, respectively. The under-predicted O3 improvements in the NOx SIP Call region could not be explained by adjusting for temperature biases in the meteorological input, or by considering uncertainties in the chemical reaction rate constants. However, the under-prediction in O3 improvements could be alleviated by 5%-31% by constraining NOx emissions in each year based on observed NOx concentrations. This demonstrates the crucial need to accurately characterize changes in precursor emissions when dynamically evaluating a model's ability to simulate O3 responses to those changes.

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

    PubMed

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

    2010-03-01

    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 important source of pollution in these National Parks. Comparisons of forecasted and observed values demonstrated that accurate forecasts of next-day hourly ozone levels may be achieved by using a time series model with historic averages, expected local weather and modeled PM values as explanatory variables. Results on fire smoke influence indicated occurrence of significant increases in average ozone levels with increasing fire activity. The overall effect on diurnal ozone values, however, was small when compared with the amount of variability attributed to sources other than fire.

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

    PubMed

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

    2010-03-01

    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 important source of pollution in these National Parks. Comparisons of forecasted and observed values demonstrated that accurate forecasts of next-day hourly ozone levels may be achieved by using a time series model with historic averages, expected local weather and modeled PM values as explanatory variables. Results on fire smoke influence indicated occurrence of significant increases in average ozone levels with increasing fire activity. The overall effect on diurnal ozone values, however, was small when compared with the amount of variability attributed to sources other than fire. PMID:19914752

  3. Record low global ozone in 1992

    SciTech Connect

    Gleason, J.F. ); Bhartia, P.K.; Herman, J.R.; McPeters, R.; Newman, P.; Stolarski, R.S. ); Flynn, L. ); Labow, G.; Larko, D.; Seftor, C.; Wellemeyer, C. ); Komhyr, W.D. ); Miller, A.J.; Planet, W. )

    1993-04-23

    The 1992 global average total ozone, measured by the Total Ozone Mapping Spectrometer (TOMS) on the Nimbus-7 satellite, was 2 to 3 percent lower than any earlier year observed by TOMS (1979 to 1991). Ozone amounts were low in a wide range of latitudes in both the Northern and Southern hemispheres, and the largest decreases were in the regions from 10[degrees]S to 20[degrees]S and 10[degrees]N to 60[degrees]N. Global ozone in 1992 is at least 1.5 percent lower than would be predicted by a statistical model that includes a linear trend and accounts for solar cycle variation and the quasi-biennial oscillation. These results are confirmed by comparisons with data from other ozone monitoring instruments: the SBUV/2 instrument on the NOAA-11 satellite, the TOMS instrument on the Russian Meteor-3 satellite, the World Standard Dobson instrument 83, and a collection of 22 ground-based Dobson instruments.

  4. The Hole in the Ozone Layer.

    ERIC Educational Resources Information Center

    Hamers, Jeanne S.; Jacob, Anthony T.

    This document contains information on the hole in the ozone layer. Topics discussed include properties of ozone, ozone in the atmosphere, chlorofluorocarbons, stratospheric ozone depletion, effects of ozone depletion on life, regulation of substances that deplete the ozone layer, alternatives to CFCs and Halons, and the future of the ozone layer.…

  5. A national fine spatial scale land-use regression model for ozone.

    PubMed

    Kerckhoffs, Jules; Wang, Meng; Meliefste, Kees; Malmqvist, Ebba; Fischer, Paul; Janssen, Nicole A H; Beelen, Rob; Hoek, Gerard

    2015-07-01

    Uncertainty about health effects of long-term ozone exposure remains. Land use regression (LUR) models have been used successfully for modeling fine scale spatial variation of primary pollutants but very limited for ozone. Our objective was to assess the feasibility of developing a national LUR model for ozone at a fine spatial scale. Ozone concentrations were measured with passive samplers at 90 locations across the Netherlands (19 regional background, 36 urban background, 35 traffic). All sites were measured simultaneously during four 2-weekly campaigns spread over the seasons. LUR models were developed for the summer average as the primary exposure and annual average using predictor variables obtained with Geographic Information Systems. Summer average ozone concentrations varied between 32 and 61 µg/m(3). Ozone concentrations at traffic sites were on average 9 µg/m(3) lower compared to regional background sites. Ozone correlated highly negatively with nitrogen dioxide and moderately with fine particles. A LUR model including small-scale traffic, large-scale address density, urban green and a region indicator explained 71% of the spatial variation in summer average ozone concentrations. Land use regression modeling is a promising method to assess ozone spatial variation, but the high correlation with NO2 limits application in epidemiology.

  6. The 2010 Antarctic ozone hole: observed reduction in ozone destruction by minor sudden stratospheric warmings.

    PubMed

    de Laat, A T J; van Weele, M

    2011-01-01

    Satellite observations show that the 2010 Antarctic ozone hole is characterized by anomalously small amounts of photochemical ozone destruction (40-60% less than the 2005-2009 average). Observations from the MLS instrument show that this is mainly related to reduced photochemical ozone destruction between 20-25 km altitude. Lower down between 15-20 km the atmospheric chemical composition and photochemical ozone destruction is unaffected. The modified chemical composition and chemistry between 20-25 km altitude in 2010 is related to the occurrence of a mid-winter minor Antarctic Sudden Stratospheric Warming (SSW). The measurements indicate that the changes in chemical composition are related to downward motion of air masses rather than horizontal mixing, and affect stratospheric chemistry for several months. Since 1979, years with similar anomalously small amounts of ozone destruction are all characterized by either minor or major SSWs, illustrating that their presence has been a necessary pre-condition for reduced Antarctic stratospheric ozone destruction. PMID:22355557

  7. Fundamentals of ISCO Using Ozone

    EPA Science Inventory

    In situ chemical oxidation (ISCO) using ozone involves the introduction of ozone gas (O3) into the subsurface to degrade organic contaminants of concern. Ozone is tri-molecular oxygen (O2) that is a gas under atmospheric conditions and is a strong oxidant. Ozone may react with ...

  8. 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)

  9. Greenhouse gases and recovery of the Earth's ozone layer

    NASA Astrophysics Data System (ADS)

    Dyominov, I. G.; Zadorozhny, A. M.

    A numerical two-dimension zonally average interactive dynamical radiative-photochemical model of the atmosphere is used for investigation the role of the greenhouse gases CO2, CH4, and N2O in the recovery of the Earth's ozone layer after reduction of anthropogenic discharges in the atmosphere of chlorine and bromine compounds. The model allows calculating self-consistently diabatic circulation, temperature, gaseous composition of the troposphere and stratosphere at latitudes from the South to North Poles, as well as distribution of sulphate aerosol particles and polar stratospheric clouds of types I and II. The scenarios of future changes of the greenhouse gases and chlorine and bromine species are taken from Climate Change 1995. The calculations show that expected cooling of the stratosphere caused by the increasing of the greenhouse gases, particularly CO2, enhances the ozone concentration in the stratosphere due to a weakness of the efficiencies of all catalytic cycles of the ozone destruction caused by temperature dependencies of photochemical reactions. The result of this effect is a significant acceleration of the ozone layer recovery after reduction of anthropogenic discharges in the atmosphere of chlorine and bromine species. On the other hand, the cooling of the stratosphere intensifies a formation of the polar stratospheric clouds in the lower stratosphere in the Polar Regions. Heterogeneous reactions on the polar stratospheric clouds, which are the key processes in the destruction of the ozone layer at the high latitudes, lead to more intensive ozone depletion here, which causes a delay of the ozone layer recovery. The calculations show that this effect is weaker than the first one so that the global ozone will recover faster under conditions of continuing anthropogenic growth of the greenhouse gases. The model predicts in this case that the annual average global ozone will reach its undisturbed level of 1980 by about 2040. If the growth of the

  10. Threshold exceedances and cumulative ozone exposure indices at tropical suburban site

    NASA Astrophysics Data System (ADS)

    Beig, G.; Ghude, Sachin D.; Polade, S. D.; Tyagi, B.

    2008-01-01

    This study provides the first analysis of threshold exceedances and cumulative ozone exposure indices from Pune, a tropical suburban site in India. We used the directives on ozone pollution in ambient air provided by the United Nations Economic Commission for Europe, and by the World Health Organization to assess the air quality from in situ measurements of surface ozone (during the years 2003-2006). We find that the exposure-plant response index (Accumulated exposure Over a Threshold of 40 ppb (AOT40)) and target values for protection of human health (8-h > 60 ppb) are regularly surpassed. This is a concern for agricultural and human health. Air-mass classification based on back-air trajectories shows that the excess of AOT40 values is quite plausibly due to long-range transport of background ozone and its precursors to the measurement site.

  11. Ozone measurements in Amazonia: Dry season versus wet season

    SciTech Connect

    Kirchhoff, V.W.J.H. ); Da Silva, I.M.O. ); Browell, E.V. )

    1990-09-20

    Observations were made almost continuously at the surface, and in addition, 20 ozone profiles were obtained in the troposphere and stratosphere. These ozone measurements were part of a field expedition to the Brazilian Amazon region, the ABLE 2B mission, a joint American-Brazilian effort to measure local concentrations of several species relevant to atmospheric chemistry. The time period of this expedition was April-May 1987, during the local wet season. For the surface ozone data the measurement technique sued was UV absorption. Ozone profiles were obtained with electrochemical concentration cell sondes, launched on balloons. The major site of operation was set up near Manaus (3{degree}S, 60{degree}W). The results are presented and compared with a previous dry season experiment. Surface ozone mixing ratios show diurnal variations that have maxima in the daytime and minima at night. The diurnal maximum at noontime, considered very low (12 ppbv) in the dry season was even lower in this wet season period (6 ppbv). A significant difference can be seen between clearing and forest data, and between different height levels above the surface, showing the existence of a large positive gradient of ozone with height. The ozone profiles in the troposphere show that there is less ozone not only at the surface but in the whole troposphere, with the wet season average showing between 6 and 12 ppbv less ozone. This difference is much smaller in the stratosphere, where there is slightly more ozone in the region of the peak, during the wet season. An isolated shower or thunderstorm in the dry season could produce transient ozone variations (mixing ratio increases or decreases) that were not observed in the wet season.

  12. Average density in cosmology

    SciTech Connect

    Bonnor, W.B.

    1987-05-01

    The Einstein-Straus (1945) vacuole is here used to represent a bound cluster of galaxies embedded in a standard pressure-free cosmological model, and the average density of the cluster is compared with the density of the surrounding cosmic fluid. The two are nearly but not quite equal, and the more condensed the cluster, the greater the difference. A theoretical consequence of the discrepancy between the two densities is discussed. 25 references.

  13. Volumetric Properties of the Mixture Cyclooctane C8H16 + C16H34 Hexadecane (VMSD1342, LB3808_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclooctane C8H16 + C16H34 Hexadecane (VMSD1342, LB3808_V)' providing data by calculation of isothermal compressibility from direct measurements of mass densities at variable pressure and constant temperature and mole fraction.

  14. Volumetric Properties of the Mixture Heptane C7H16 + C8H16 Cyclooctane (VMSD1342, LB3802_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Heptane C7H16 + C8H16 Cyclooctane (VMSD1342, LB3802_V)' providing data by calculation of isothermal compressibility from direct measurements of mass densities at variable pressure and constant temperature and mole fraction.

  15. Volumetric Properties of the Mixture Hexane C6H14 + C8H16 Cyclooctane (VMSD1342, LB3815_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Hexane C6H14 + C8H16 Cyclooctane (VMSD1342, LB3815_V)' providing data by calculation of isothermal compressibility from direct measurements of mass densities at variable pressure and constant temperature and mole fraction.

  16. Volumetric Properties of the Mixture Cyclooctane C8H16 + C14H30 Tetradecane (VMSD1342, LB3801_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclooctane C8H16 + C14H30 Tetradecane (VMSD1342, LB3801_V)' providing data by calculation of isothermal compressibility from direct measurements of mass densities at variable pressure and constant temperature and mole fraction.

  17. Volumetric Properties of the Mixture Cyclooctane C8H16 + C10H22 Decane (VMSD1342, LB3816_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclooctane C8H16 + C10H22 Decane (VMSD1342, LB3816_V)' providing data by calculation of isothermal compressibility from direct measurements of mass densities at variable pressure and constant temperature and mole fraction.

  18. Volumetric Properties of the Mixture Pentane C5H12 + C8H16 Cyclooctane (VMSD1342, LB3814_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Pentane C5H12 + C8H16 Cyclooctane (VMSD1342, LB3814_V)' providing data by calculation of isothermal compressibility from direct measurements of mass densities at variable pressure and constant temperature and mole fraction.

  19. Volumetric Properties of the Mixture Octane C8H18 + C14H30 Tetradecane (VMSD1241, LB3874_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Octane C8H18 + C14H30 Tetradecane (VMSD1241, LB3874_V)' providing data from direct high-pressure dilatometric measurements of molar excess volume at variable pressure and constant temperature and mole fraction.

  20. The Role of Galveston Bay Meteorology in Ozone Concentrations in Houston, Texas

    NASA Astrophysics Data System (ADS)

    Nielsen-Gammon, J. W.; Tobin, J.

    2007-12-01

    Galveston Bay is a body of water approximately 50 km by 30 km that opens into the Gulf of Mexico. The head of Galveston Bay is adjacent to the Houston Ship Channel, where large industrial emitters of ozone precursors are located. We consider the role of coastal circulations and mixing suppression over Galveston Bay in the location and magnitude of peak 8-h ozone values at monitors within the Houston-Galveston-Brazoria nonattainment area. Galveston Bay is found to have a salutary effect on ozone concentrations under most circumstances. Aside from boats and ships, Galveston Bay is free of ozone precursor emissions, and the onset of the sea breeze along Galveston Bay usually causes an immediate drop in ozone levels. The situation changes dramatically when the morning wind direction is from the northwest, allowing ozone precursors emitted during the night or early morning that are distributed in a shallow atmospheric layer to be carried over Galveston Bay. In morning and early afternoon, mixing is suppressed over Galveston Bay, and precursor concentrations remain high in the absence of ventilation. If winds are strong, high ozone concentrations are generally observed along the far shore of Galveston Bay. If winds are weak, a sea breeze will develop along Galveston Bay, and high levels of ozone will be carried back onshore in the vicinity of the Ship Channel. The coastal oscillation (a regular rotation of the wind vector driving by coastal heating contrasts near 30 N) can lead to wind reversals and high values of ozone by itself. We investigate peak ozone concentrations under a variety of wind conditions to infer whether the ozone concentrations are, on balance, higher due to the net effect of meteorological processes associated with Galveston Bay.

  1. 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.

  2. 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.

  3. Indoor/outdoor concentrations of ozone and peroxyacetyl nitrate (PAN).

    PubMed

    Jakobi, G; Fabian, P

    1997-05-01

    Photochemical pollutants such as ozone and peroxyacetyl nitrate (PAN) could adversely affect human health, especially with relation to effects on lung function. For a realistic assessment of ambient concentrations, both outdoor and indoor measurements of ozone and PAN are required, because people stay indoors for most of the time. Indoor/outdoor concentration ratios, indoor half-life times and indoor chemistry including physicochemical reactions on surfaces are quite well known for ozone, but not for PAN. While ozone is removed very rapidly mainly by heterogeneous reactions on surfaces or by gasphase reactions with e.g. carpet emissions, no such processes are known for PAN at present. The main removal process for PAN is thermal decay. Indoor concentrations of ozone and PAN can be a significant fraction of those outdoors highly depending on the ventilation pattern. Our measurements in various kinds of non-air-conditioned rooms show maximal indoor concentrations between 80 and 100% of those outdoors for ozone and PAN, respectively. Average indoor/outdoor ratios were calculated of 0.5 for ozone and between 0.7 and 0.9 for PAN. The half-life times ranged between only a few minutes for ozone and 0.5 to 1 h for PAN.

  4. Stratospheric ozone depletion.

    PubMed

    Rowland, F Sherwood

    2006-05-29

    Solar ultraviolet radiation creates an ozone layer in the atmosphere which in turn completely absorbs the most energetic fraction of this radiation. This process both warms the air, creating the stratosphere between 15 and 50 km altitude, and protects the biological activities at the Earth's surface from this damaging radiation. In the last half-century, the chemical mechanisms operating within the ozone layer have been shown to include very efficient catalytic chain reactions involving the chemical species HO, HO2, NO, NO2, Cl and ClO. The NOX and ClOX chains involve the emission at Earth's surface of stable molecules in very low concentration (N2O, CCl2F2, CCl3F, etc.) which wander in the atmosphere for as long as a century before absorbing ultraviolet radiation and decomposing to create NO and Cl in the middle of the stratospheric ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the stratosphere, with the result that more solar ultraviolet-B radiation (290-320 nm wavelength) reaches the surface. This ozone loss occurs in the temperate zone latitudes in all seasons, and especially drastically since the early 1980s in the south polar springtime-the 'Antarctic ozone hole'. The chemical reactions causing this ozone depletion are primarily based on atomic Cl and ClO, the product of its reaction with ozone. The further manufacture of chlorofluorocarbons has been banned by the 1992 revisions of the 1987 Montreal Protocol of the United Nations. Atmospheric measurements have confirmed that the Protocol has been very successful in reducing further emissions of these molecules. Recovery of the stratosphere to the ozone conditions of the 1950s will occur slowly over the rest of the twenty-first century because of the long lifetime of the precursor molecules.

  5. Stratospheric ozone depletion

    PubMed Central

    Rowland, F. Sherwood

    2006-01-01

    Solar ultraviolet radiation creates an ozone layer in the atmosphere which in turn completely absorbs the most energetic fraction of this radiation. This process both warms the air, creating the stratosphere between 15 and 50 km altitude, and protects the biological activities at the Earth's surface from this damaging radiation. In the last half-century, the chemical mechanisms operating within the ozone layer have been shown to include very efficient catalytic chain reactions involving the chemical species HO, HO2, NO, NO2, Cl and ClO. The NOX and ClOX chains involve the emission at Earth's surface of stable molecules in very low concentration (N2O, CCl2F2, CCl3F, etc.) which wander in the atmosphere for as long as a century before absorbing ultraviolet radiation and decomposing to create NO and Cl in the middle of the stratospheric ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the stratosphere, with the result that more solar ultraviolet-B radiation (290–320 nm wavelength) reaches the surface. This ozone loss occurs in the temperate zone latitudes in all seasons, and especially drastically since the early 1980s in the south polar springtime—the ‘Antarctic ozone hole’. The chemical reactions causing this ozone depletion are primarily based on atomic Cl and ClO, the product of its reaction with ozone. The further manufacture of chlorofluorocarbons has been banned by the 1992 revisions of the 1987 Montreal Protocol of the United Nations. Atmospheric measurements have confirmed that the Protocol has been very successful in reducing further emissions of these molecules. Recovery of the stratosphere to the ozone conditions of the 1950s will occur slowly over the rest of the twenty-first century because of the long lifetime of the precursor molecules. PMID:16627294

  6. Stratospheric ozone depletion.

    PubMed

    Rowland, F Sherwood

    2006-05-29

    Solar ultraviolet radiation creates an ozone layer in the atmosphere which in turn completely absorbs the most energetic fraction of this radiation. This process both warms the air, creating the stratosphere between 15 and 50 km altitude, and protects the biological activities at the Earth's surface from this damaging radiation. In the last half-century, the chemical mechanisms operating within the ozone layer have been shown to include very efficient catalytic chain reactions involving the chemical species HO, HO2, NO, NO2, Cl and ClO. The NOX and ClOX chains involve the emission at Earth's surface of stable molecules in very low concentration (N2O, CCl2F2, CCl3F, etc.) which wander in the atmosphere for as long as a century before absorbing ultraviolet radiation and decomposing to create NO and Cl in the middle of the stratospheric ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the stratosphere, with the result that more solar ultraviolet-B radiation (290-320 nm wavelength) reaches the surface. This ozone loss occurs in the temperate zone latitudes in all seasons, and especially drastically since the early 1980s in the south polar springtime-the 'Antarctic ozone hole'. The chemical reactions causing this ozone depletion are primarily based on atomic Cl and ClO, the product of its reaction with ozone. The further manufacture of chlorofluorocarbons has been banned by the 1992 revisions of the 1987 Montreal Protocol of the United Nations. Atmospheric measurements have confirmed that the Protocol has been very successful in reducing further emissions of these molecules. Recovery of the stratosphere to the ozone conditions of the 1950s will occur slowly over the rest of the twenty-first century because of the long lifetime of the precursor molecules. PMID:16627294

  7. [Influence of ozone on snap bean under ambient air in two sites of northern China].

    PubMed

    Yuan, Xiang-Yang; Zhang, Wei-Wei; Sun, Jing-Song; Hu, En-Zhu; Zhang, Yu-Long; Zhang, Hong-Xing; Tian, Yuan; Feng, Zhao-Zhong

    2014-08-01

    Tropospheric ozone (O3) has been assumed the most phytotoxic air pollutant and the snap bean (Phaseolus vulgaris L.) is known to be an ozone-sensitive species. Two genotypes (R123, ozone-tolerance, S156, ozone-sensitivity) of snap bean were explored in three places. The objective of this study was to evaluate whether the snap bean was influenced under the current ambient ozone concentration. The findings indicated that the leaves of bean grown at Research Center for Eco-Environmental Sciences (RCEES), Chinese Academy of Sciences and ChangPing showed visible ozone symptoms under the ambient ozone concentration, and the averaged ozone injury proportion in S156 was 23.5% higher than R123 during the entire growth season. The ozone damage to the snap bean depends on the plant growing stages. The injury symptoms appeared just after flowering, increased from the stages of flowering to pod formation, and reached the maximum at the stages of pod maturation. The ratio of S156/R123 in pod yield was 0.48, and 0.24 and 0.73 in the RCEES, ChangPing and Harbin, respectively. The ratio close to 1 was assumed that the plant growth is not affected by ozone, and the lower ratio is, the more damage caused by ozone. Obviously, the current ambient ozone concentration of Beijing area has significantly caused the yield loss of snap bean.

  8. Ozone - plant surface reactions an important ozone loss term?

    NASA Astrophysics Data System (ADS)

    Hansel, Armin; Jud, Werner; Fischer, Lukas; Canaval, Eva; Wohlfahrt, Georg; Tissier, Alain

    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 billions dollar per year. Plant injuries have been related to the uptake of ozone through stomatal pores and oxidative effects damaging the internal leaf tissue. But a striking question remains: How much ozone enters the plant through open stomata and how much ozone is lost by chemical reactions at the plant surface? Until now surface losses are estimated from measured total ozone deposition fluxes and calculated stomatal conductance values. While stomatal conductance of CO2 and H2O is well understood and extensively used in describing plant atmosphere gas exchange, stomatal conductance of ozone is not well known. Here we use different Nicotiana tabacum varieties and find that surface reactions of ozone with diterpenoids synthesized by glandular trichomes reduce ozone flux through open stomata. Our measurements reveal that fast ozone loss at the plant surface is accompanied with prompt release of oxygenated volatile compounds. In the ozone fumigation experiments of different Nicotiana tabacum varieties the release of specific volatile oxy-VOCs allowed to identify the semi volatile precursor compounds at the plant surface. Ozone fumigation experiments with Norway spruce (Picea abies) and Scots Pine (Pinus sylvestris), two common species in the Northern Hemisphere, show also a significant ozone loss at the plant surface for Picea abies. Fluid dynamic calculations of ozone transport in the diffusive leaf boundary layer reveal a vertical but no horizontal ozone gradient thus reducing ozone fluxes through the pores in case of efficient ozone scavenging plant surfaces. We explain this efficient ozone protection mechanism by the porous surface architecture of plants in combination with unsaturated semi-volatile compounds deposited at the plant surface. These results show that unsaturated semi-volatile compounds at

  9. Ozone Profiles and Tropospheric Ozone from Global Ozone Monitoring Experiment

    NASA Technical Reports Server (NTRS)

    Liu, X.; Chance, K.; Sioris, C. E.; Sparr, R. J. D.; Kuregm, T. P.; Martin, R. V.; Newchurch, M. J.; Bhartia, P. K.

    2003-01-01

    Ozone profiles are derived from backscattered radiances in the ultraviolet spectra (290-340 nm) measured by the nadir-viewing Global Ozone Monitoring Experiment using optimal estimation. Tropospheric O3 is directly retrieved with the tropopause as one of the retrieval levels. To optimize the retrieval and improve the fitting precision needed for tropospheric O3, we perform extensive wavelength and radiometric calibrations and improve forward model inputs. Retrieved O3 profiles and tropospheric O3 agree well with coincident ozonesonde measurements, and the integrated total O3 agrees very well with Earth Probe TOMS and Dobson/Brewer total O3. The global distribution of tropospheric O3 clearly shows the influences of biomass burning, convection, and air pollution, and is generally consistent with our current understanding.

  10. Antarctic Ozone loss 1988-2008 history at Dumont d

    NASA Astrophysics Data System (ADS)

    Kuttippurath, J.; Goutail, F.; Pommereau, J. P.; Pazmino, A.; Feng, W.; Chipperfield, M.

    2009-04-01

    Even if the saturation of Antarctic ozone loss is almost achieved, the time of ozone recovery to pre-industrial level is still uncertain. In order to make amendments in international treaties aimed at controlling ozone depleting substances (ODS), the long term monitoring of ozone level by independent and complementary space borne and ground-based observations is mandatory. The consistency between the two approaches and model simulations is being investigated by comparison of ozone depleted amounts derived every year since 1988 by the transport method above the French NDACC station of Dumont d'Urville from the measurements of the G-B SAOZ UV-Vis and the series of TOMS-Nimbus, -Meteor, -Earth Probe and OMI, and simulations by the SLIMCAT 3D CTM. The loss derived from SAOZ is 5% larger than that shown by TOMS, whereas the difference vanishes in 2006 and 2007 with OMI. The cumulative depletion in the vortex estimated from a ten-day average of ozone loss at 475 K during the winter is 55% on average. The strongest depletion is occurred in 1994, 1995, 1997 and 2006 exceeding 60%, whereas the lowest of less than 50% is observed in 1988, 1992, 2002, 2005 and 2007. There is indication of an increasing trend in the ozone loss in 1988-1994 related to the increase in ODS, followed by a level off or a small decreasing trend since 1996.

  11. [Effects of synoptic type on surface ozone pollution in Beijing].

    PubMed

    Tang, Gui-qian; Li, Xin; Wang, Xiao-ke; Xin, Jin-yuan; Hu, Bo; Wang, Li-li; Ren, Yu-fen; Wang, Yue-Si

    2010-03-01

    Ozone (O), influenced by meteorological factors, is a primary gaseous photochemical pollutant during summer to fall in Beijing' s urban ambient. Continuous monitoring during July to September in 2008 was carried out at four sites in Beijing. Analyzed with synoptic type, the results show that the ratios of pre-low cylonic (mainly Mongolia cyclone) and pre-high anticylonic to total weather conditions are about 42% and 20%, illustrating the high-and low-ozone episodes, respectively. At the pre-low cylonic conditions, high temperature, low humidity, mountain and valley winds caused by local circulation induce average hourly maximum ozone concentration (volume fraction) up to 102.2 x 10(-9), negative correlated with atmospheric pressure with a slope of -3.4 x 10(-9) Pa(-1). The time of mountain wind changed to valley wind dominates the diurnal time of maximum ozone, generally around 14:00. At the pre-high anticylonic conditions, low temperature, high humidity and systematic north wind induce average hourly maximum ozone concentration (volume fraction) only 49.3 x 10(-9), the diurnal time of maximum ozone is deferred by continuous north wind till about 16:00. The consistency of photochemical pollution in Beijing region shows that good correlation exists between synoptic type and ozone concentration. Therefore, getting an eye on the structure and evolution of synoptic type is of great significances for forecasting the photochemical pollution.

  12. Ozone Photolysis: Strong Isotopologue/isotopomer Selectivity in the Stratosphere

    NASA Astrophysics Data System (ADS)

    Gatti, Fabien; Ndengue, Steve; Jost, Remy; Halasz, Gabor; Vibok, Agnes

    2013-06-01

    Using the visible-UV absorption cross section (Abs. XS) of five ozone isotopologues and an averaged actinic flux, we have calculated the contribution of the atmospheric ozone photolysis to the oxygen isotope and ozone isotopologue/isotopomer enrichment. Five ozone isotopologues/isotopomers are considered among which three are symmetric, O^{16}3 (noted 666), O^{16}O^{17}O^{16} (676) and O^{16}O^{18}O^{16} (686), and two are asymmetric, O^{17}O^{16}_2 (667) and O^{18}O^{16}_2 (668). The photolysis rates of the five ozone isotopologues have been calculated as a function of altitude. The Multi Configuration Time Dependent Hartree (MCTDH) method and the potential energy surfaces calculates by R. Schinke and coworkers have been used. We have used experimental actinic fluxes, averaged for latitude and season, for altitudes varying by step of 4km up to 80km. Below 35km, the contribution of the Hartley band to the photolysis rates is restricted to its low energy range, named the Huggins band, which has strong isotopologue/isotopomer selectivity and then induces strong enrichment. Consequently, the isotopologue enrichment's due to ozone photolysis are strongly dependent of the altitude, with pronounced enrichment peaks around 35 km, the altitude corresponding to the maximum relative contribution of the Huggins band. We will also present some new simulations for the simulation of laser-induced quantum dynamics of the electronic and nuclear motion in the ozone molecule on the attosecond time scale.

  13. Polar Ozone Losses

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Bhartia, P. K. (Technical Monitor)

    2001-01-01

    Since the discovery of the Antarctic ozone hole, a great deal of attention has been focused on the polar regions to both identify the chemistry and physics of the large losses, and to provide an understanding of the future of polar ozone. In this review talk, I will discuss the secular trends of ozone in both the Antarctic and Arctic regions, and I will review some of the principal research results of the last few years. In particular, I will emphasize some of the results from the SOLVE-THESEO 2000 campaign that occurred over the course of the winter of 1999-2000.

  14. Arctic ozone loss

    SciTech Connect

    Zurer, P.S.

    1989-03-06

    Scientists have returned from the first comprehensive probe of the Arctic stratosphere with unexpectedly dire results: The winter atmosphere in the north polar region is loaded with the same destructive chlorine compounds that cause the Antarctic ozone hole. Atmospheric researchers who only a few weeks ago were comforted by the thought that the warmer Northern Hemisphere is strongly protected from the processes that lead to massive losses of ozone during spring in Antarctica now see very little standing in the way of an Arctic ozone hole.

  15. Lidar-derived Correlations Between Lower-tropospheric Column and Surface Ozone: Implications for Satellite Observations

    NASA Astrophysics Data System (ADS)

    Senff, C. J.; Langford, A. O.; Alvarez, R. J. _II, II; Kirgis, G.; Choukulkar, A.; Brewer, A.; Banta, R. M.; Weickmann, A. M.; Sandberg, S.; Olson, E.

    2015-12-01

    One of the data products that will be provided by the TEMPO satellite mission is 0-2 km ozone column concentration. To make inferences about surface air quality from this data product, the relationship between lower-tropospheric column and surface ozone concentrations and their diurnal, seasonal, and spatial variations have to be well understood. To characterize these relationships, we have used ozone profile observations obtained with NOAA's truck-based, scanning TOPAZ ozone lidar from several recent field campaigns including Discover-AQ Houston and Colorado, the Uintah Basin Wintertime Ozone Study (UBWOS), and the Las Vegas Ozone Study (LVOS). The TOPAZ lidar is ideally suited for this kind of study because it provides ozone profiles from about 15 m above ground level (AGL) up to 3 km AGL at high spatial and temporal resolution. We have used the lidar observations closest to the ground as a proxy for surface ozone and compared them to the 0-2 km AGL average column ozone concentrations measured with the lidar. Results from the Discover-AQ Colorado campaign show that in the afternoon, when the boundary layer (BL) was deep and well mixed, ozone column and surface concentrations agreed quite well. However, during the morning hours, ozone column concentrations were significantly higher than those at the surface, because ozone was depleted in a shallow surface layer due to titration and deposition, whereas ozone levels in the residual layer aloft remained moderately high. The analysis of column and surface ozone correlations using ozone lidar observations from the Discover-AQ Houston, UBWOS and LVOS campaigns is currently underway. The results from these studies will provide additional insights into the relationship between column and surface ozone, in particular their variation as a function of measurement location and season, and their dependence on BL processes such as mixed layer height evolution, land-sea breeze circulation, and terrain-induced flows.

  16. ROCOZ-A ozone measurements during the Stratospheric Ozone Intercomparison Campaign (STOIC)

    NASA Astrophysics Data System (ADS)

    Barnes, Robert A.; Parsons, Chester L.; Grothouse, Arthur P.

    1995-05-01

    We present a set of ROCOZ-A (rocket ozonesonde) ozone measurements during the October/November 1988 (pre-STOIC) and the July/August 1989 Stratospheric Ozone Intercomparison Campaign (STOIC) in southern California. ROCOZ-A and its associated electrochemical concentration cell (ECC) ozonesondes participated in the comparisons as established techniques for the validation of lidar and microwave instruments that have been proposed for the Network for the Detection of Stratospheric Change (NDSC). For the proposed network instruments, STOIC has provided a picture of their performance characteristics in 1989 and has given an estimate of their future performance in the NDSC. For ROCOZ-A, STOIC has added new information on its accuracy and precision. It is this continuing characterization that gives ROCOZ-A its value in comparisons. The STOIC comparisons show a shift of 5-6% in ROCOZ-A ozone densities (ROCOZ-A higher) from October/November 1988 to July/August 1989. This shift has been seen in comparisons with the Stratospheric Aerosol and Gas Experiment II (SAGE II), ECC ozonesondes, and the Jet Propulsion Laboratory (JPL) lidar. The source of this shift has not been determined. Until this new error source is resolved, we recommend that the previously quoted accuracy estimate for ROCOZ-A ozone measurements be increased from 5-7% to 8-10%. About 2% of the difference between ROCOZ-A ozone measurements and those from the proposed network instruments in 1989 appears to be due to differences in atmospheric ozone between the two STOIC sites. A correction for these site-to-site differences brings the ROCOZ-A ozone measurements within 10% of all of the other STOIC instruments, and the average agreement (ROCOZ-A 6% higher) becomes consistent with the historical set of ROCOZ-A comparisons. The STOIC comparisons have shown structures in stratospheric ozone that cannot be resolved by ROCOZ-A with its 4-km vertical resolution. In addition, comparisons with nighttime measurements from the

  17. Role of neutrophilic inflammation in ozone-induced epithelial alterations in the nasal airways of rats

    NASA Astrophysics Data System (ADS)

    Cho, Hye Youn

    Ozone is a principal oxidant air pollutant in photochemical smog. Epithelial cells lining the centriacinar region of lung and the proximal aspects of nasal passage are primary target sites for ozone-induced injury in laboratory animals. Acute exposure of rats to high ambient concentrations of ozone (e.g., 0.5 ppm) results in neutrophilic inflammation, epithelial hyperplasia and mucous cell metaplasia (MCM) in the nasal transitional epithelium (NTE) lining the proximal nasal airways. The principal purpose of the present study was to investigate the role of pre-metaplastic cellular responses, especially neutrophilic inflammation, in the pathogenesis of ozone-induced MCM in rat NTE. For this purpose, three specific hypotheses-based whole-animal inhalation studies were conducted. Male F344/N rats were exposed in whole-body inhalation chambers to 0 (filtered air) or 0.5 ppm ozone for 1-3 days (8 h/day). Histochemical, immunochemical, molecular and morphometric techniques were used to investigate the ozone-induced cellular and molecular events in the NTE. Two in vitro studies were also conducted to examine the effects of ozone-inducible cytokines (i.e., tumor necrosis factor-alpha; TNF- a, and interleukin-6; IL-6) on mucin gene (rMuc-5AC) expression. Ozone induced a rapid increase of rMuc-5AC mRNA in nasal tissues within hours after the start of exposure. It preceded the appearance of MCM, and persisted with MCM. Ozone-induced neutrophilic inflammation accompanied the mucin gene upregulation, but was resolved when MCM first appeared in the NTE. Antibody-mediated depletion of circulating neutrophils attenuated ozone-induced MCM, although it did not affect the ozone-induced epithelial hyperplasia and mucin mRNA upregulation. In another study, it was found that preexisting neutrophilic rhinitis induced by endotoxin augmented the ozone-induced MCM. However, pre-existing rhinitis did not alter the severity of ozone-induced epithelial hyperplasia and mucin gene upregulation

  18. Energetic particle precipitation: A major driver of the ozone budget in the Antarctic upper stratosphere

    NASA Astrophysics Data System (ADS)

    Damiani, Alessandro; Funke, Bernd; Santee, Michelle L.; Cordero, Raul R.; Watanabe, Shingo

    2016-04-01

    Geomagnetic activity is thought to affect ozone and, possibly, climate in polar regions via energetic particle precipitation (EPP) but observational evidence of its importance in the seasonal stratospheric ozone variation on long time scales is still lacking. Here we fill this gap by showing that at high southern latitudes, late winter ozone series, covering the 1979-2014 period, exhibit an average stratospheric depletion of about 10-15% on a monthly basis caused by EPP. Daily observations indicate that every austral winter EPP-induced low ozone concentrations appear at about 45 km in late June and descend later to 30 km, before disappearing by September. Such stratospheric variations are coupled with mesospheric ozone changes also driven by EPP. No significant correlation between these ozone variations and solar ultraviolet irradiance has been found. This suggests the need of including the EPP forcing in both ozone model simulations and trend analysis.

  19. Variability and sources of surface ozone at rural sites in Nevada, USA: Results from two years of the Nevada Rural Ozone Initiative.

    PubMed

    Fine, Rebekka; Miller, Matthieu B; Burley, Joel; Jaffe, Daniel A; Pierce, R Bradley; Lin, Meiyun; Gustin, Mae Sexauer

    2015-10-15

    Ozone (O3) has been measured at Great Basin National Park (GBNP) since September 1993. GBNP is located in a remote, rural area of eastern Nevada. Data indicate that GBNP will not comply with a more stringent National Ambient Air Quality Standard (NAAQS) for O3, which is based upon the 3-year average of the annual 4th highest Maximum Daily 8-h Average (MDA8) concentration. Trend analyses for GBNP data collected from 1993 to 2013 indicate that MDA8 O3 increased significantly for November to February, and May. The greatest increase was for May at 0.38, 0.35, and 0.46 ppb yr(-1) for the 95th, 50th, and 5th percentiles of MDA8 O3 values, respectively. With the exception of GBNP, continuous O3 monitoring in Nevada has been limited to the greater metropolitan areas. Due to the limited spatial detail of O3 measurements in rural Nevada, a network of rural monitoring sites was established beginning in July 2011. For a period ranging from July 2011 to June 2013, maximum MDA8 O3 at 6 sites occurred in the spring and summer, and ranged from 68 to 80ppb. Our analyses indicate that GBNP, in particular, is ideally positioned to intercept air containing elevated O3 derived from regional and global sources. For the 2 year period considered here, MDA8 O3 at GBNP was an average of 3.1 to 12.6 ppb higher than at other rural Nevada sites. Measured MDA8 O3 at GBNP exceeded the current regulatory threshold of 75 ppb on 7 occasions. Analyses of synoptic conditions, model tracers, and air mass back-trajectories on these days indicate that stratospheric intrusions, interstate pollution transport, wildfires, and Asian pollution contributed to elevated O3 observed at GBNP. We suggest that regional and global sources of ozone may pose challenges to achieving a more stringent O3 NAAQS in rural Nevada. PMID:25548133

  20. Ozone Correlative Measurements Workshop

    NASA Technical Reports Server (NTRS)

    Hilsenrath, E. (Editor)

    1985-01-01

    A study was conducted to determine the necessary parameters for the correlation of data on Earth ozone. Topics considered were: (1) measurement accuracy; (2) equipment considerations (SBUV); and (3) ground based measurements to support satellite data.

  1. Ozone Therapy in Dentistry

    PubMed Central

    Domb, William C

    2014-01-01

    Summary The 21st century dental practice is quite dynamic. New treatment protocols and new materials are being developed at a rapid pace. Ozone dental therapy falls into the category of new treatment protocols in dentistry, yet ozone is not new at all. Ozone therapy is already a major treatment modality in Europe, South America and a number of other countries. What is provided here will not be an exhaustive scientific treatise so much as a brief general introduction into what dentists are now doing with ozone therapies and the numerous oral/systemic links that make this subject so important for physicians so that, ultimately, they may serve their patients more effectively and productively. PMID:25363268

  2. Comparison of background ozone estimates over the western United States based on two separate model methodologies

    NASA Astrophysics Data System (ADS)

    Dolwick, Pat; Akhtar, Farhan; Baker, Kirk R.; Possiel, Norm; Simon, Heather; Tonnesen, Gail

    2015-05-01

    Two separate air quality model methodologies for estimating background ozone levels over the western U.S. are compared in this analysis. The first approach is a direct sensitivity modeling approach that considers the ozone levels that would remain after certain emissions are entirely removed (i.e., zero-out modeling). The second approach is based on an instrumented air quality model which tracks the formation of ozone within the simulation and assigns the source of that ozone to pre-identified categories (i.e., source apportionment modeling). This analysis focuses on a definition of background referred to as U.S. background (USB) which is designed to represent the influence of all sources other than U.S. anthropogenic emissions. Two separate modeling simulations were completed for an April-October 2007 period, both focused on isolating the influence of sources other than domestic manmade emissions. The zero-out modeling was conducted with the Community Multiscale Air Quality (CMAQ) model and the source apportionment modeling was completed with the Comprehensive Air Quality Model with Extensions (CAMx). Our analysis shows that the zero-out and source apportionment techniques provide relatively similar estimates of the magnitude of seasonal mean daily 8-h maximum U.S. background ozone at locations in the western U.S. when base case model ozone biases are considered. The largest differences between the two sets of USB estimates occur in urban areas where interactions with local NOx emissions can be important, especially when ozone levels are relatively low. Both methodologies conclude that seasonal mean daily 8-h maximum U.S. background ozone levels can be as high as 40-45 ppb over rural portions of the western U.S. Background fractions tend to decrease as modeled total ozone concentrations increase, with typical fractions of 75-100 percent on the lowest ozone days (<25 ppb) and typical fractions between 30 and 50% on days with ozone above 75 ppb. The finding that

  3. The ozone backlash

    SciTech Connect

    Taubes, G.

    1993-06-11

    While evidence for the role of chlorofluorocarbons in ozone depletion grows stronger, researchers have recently been subjected to vocal public criticism of their theories-and their motives. Their understanding of the mechanisms of ozone destruction-especially the annual ozone hole that appears in the Antarctic-has grown stronger, yet everywhere they go these days, they seem to be confronted by critics attacking their theories as baseless. For instance, Rush Limbaugh, the conservative political talk-show host and now-best-selling author of The Way Things Ought to Be, regularly insists that the theory of ozone depletion by CFCs is a hoax: bladerdash and poppycock. Zoologist Dixy Lee Ray, former governor of the state of Washington and former head of the Atomic Energy Commission, makes the same argument in her book, Trashing the Planet. The Wall Street Journal and National Review have run commentaries by S. Fred Singer, a former chief scientists for the Department of Transportation, purporting to shoot holes in the theory of ozone depletion. Even the June issue of Omni, a magazine with a circulation of more than 1 million that publishes a mixture of science and science fiction, printed a feature article claiming to expose ozone research as a politically motivated scam.

  4. Americans' Average Radiation Exposure

    SciTech Connect

    NA

    2000-08-11

    We live with radiation every day. We receive radiation exposures from cosmic rays, from outer space, from radon gas, and from other naturally radioactive elements in the earth. This is called natural background radiation. It includes the radiation we get from plants, animals, and from our own bodies. We also are exposed to man-made sources of radiation, including medical and dental treatments, television sets and emission from coal-fired power plants. Generally, radiation exposures from man-made sources are only a fraction of those received from natural sources. One exception is high exposures used by doctors to treat cancer patients. Each year in the United States, the average dose to people from natural and man-made radiation sources is about 360 millirem. A millirem is an extremely tiny amount of energy absorbed by tissues in the body.

  5. Long-term ozone and temperature correlations above SANAE, Antarctica

    NASA Technical Reports Server (NTRS)

    Bodeker, Gregory E.; Scourfield, Malcolm W. J.

    1994-01-01

    A significant decline in Antarctic total column ozone and upper air temperatures has been observed in recent years. Furthermore, high correlations between monthly mean values of ozone and stratospheric temperature have been measured above Syowa, Antarctica. For the observations reported here, data from TOMS (Total Ozone Mapping Spectrometer) aboard the Nimbus 7 satellite have been used to examine the 1980 to 1990 decrease in total column ozone above the South African Antarctic base of SANAE (70 deg 18 min S, 2 deg 21 min W). The cooling of the Antarctic stratosphere above SANAE during this period has been investigated by examining upper air temperatures at the 150, 100, 70, 50, and 30 hPa levels obtained from daily radiosonde balloon launches. Furthermore, these two data sets have been used to examine long-term, medium-term, and short-term correlations between total column ozone and the temperatures at each of the five levels. The trend in SANAE total column ozone has been found to be -4.9 DU/year, while upper air temperatures have been found to decrease at around 0.3 C/year. An analysis of monthly average SANAE total column ozone has shown the decrease to be most severe during the month of September with a trend of -7.7 DU/year. A strong correlation (r(exp 2) = 0.92) has been found between yearly average total column ozone and temperature at the 100 hPa level. Daily ozone and temperature correlations show high values from September to November, at a time when the polar vortex is breaking down.

  6. Ozone in the Pacific Troposphere from Ozonesonde Observations

    NASA Technical Reports Server (NTRS)

    Oltmans, S. J.; Johnson, B. J.; Harris, J. M.; Voemel, H.; Koshy, K.; Simon, P.; Bendura, R.; Thompson, A. M.; Logan, J. A.; Hasebe, F.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Ozone vertical profile measurements obtained from ozonesondes flown at Fiji, Samoa, Tahiti and the Galapagos are used to characterize ozone in the troposphere over the tropical Pacific. There is a significant seasonal variation at each of these sites. At sites in both the eastern and western Pacific, ozone is highest at almost all levels in the troposphere during the September-November season and lowest during, March-May. There is a relative maximum at all of the sites in the mid-troposphere during all seasons of the year (the largest amounts are usually found near the tropopause). This maximum is particularly pronounced during, the September-November season. On average, throughout the troposphere at all seasons, the Galapagos has larger ozone amounts than the western Pacific sites. A trajectory climatology is used to identify the major flow regimes that are associated with the characteristic ozone behavior at various altitudes and seasons. The enhanced ozone seen in the mid-troposphere during September-November is associated with flow from the continents. In the western Pacific this flow is usually from southern Africa (although 10-day trajectories do not always reach the continent), but also may come from Australia and Indonesia. In the Galapagos the ozone peak in the mid-troposphere is seen in flow from the South American continent and particularly from northern Brazil. The time of year and flow characteristics associated with the ozone mixing ratio peaks seen in both the western and eastern Pacific suggest that these enhanced ozone values result from biomass burning. In the upper troposphere low ozone amounts are seen with flow that originates in the convective western Pacific.

  7. A passive ozone sampler based on a reaction with iodide.

    PubMed

    Yanagisawa, Y

    1994-02-01

    A new passive sampler for ozone and its simple analytical system have been developed. Because it is small and sensitive, the sampler can be used for determining personal exposures to ozone and oxidants and for multilocation measurements. The sampler consists of an electrode, a spacer, and several layers of membrane filters and Teflon meshes. The electrode is a carbon paper disk coated with nylon-6 polymer and potassium iodide. The membrane filters are used to remove interferences. A sampling rate of ozone is controlled by the spacer and Teflon meshes. Iodine is liberated by an oxidation reaction of potassium iodide with ozone. The iodine is stabilized by forming a charge transfer complex with nylon-6 and is accumulated in the nylon-6 layer. The amount of iodine, which is proportional to the level of ozone exposure, is quantified by constant current coulometry. The discharge time of a galvanic battery is measured using the electrode as a positive electrode and a zinc plate as a counter electrode. A time-weighted average concentration of ozone is derived from the discharge time after exposing the electrode to ozone. The effects of various environmental conditions on the sampler's performance were investigated. The results indicated that the sampler showed a linear response to ozone exposure up to 1,450 parts per billion for every hour of use (ppb.hour). The minimum detectable exposure was about 400 ppb.hour. The effects of surface wind velocity, temperature, and humidity were small. However, a relative humidity below 20% resulted in an underestimation of the ozone concentration. Because the electrode requires no pretreatment and the analytical method is very simple, this method is suitable for large-scale studies of personal exposures to ozone and oxidants using multilocation measurements.

  8. Humanized Affinity-matured Monoclonal Antibody 8H9 Has Potent Antitumor Activity and Binds to FG Loop of Tumor Antigen B7-H3.

    PubMed

    Ahmed, Mahiuddin; Cheng, Ming; Zhao, Qi; Goldgur, Yehuda; Cheal, Sarah M; Guo, Hong-fen; Larson, Steven M; Cheung, Nai-kong V

    2015-12-11

    B7-H3 (CD276) is both an inhibitory ligand for natural killer cells and T cells and a tumor antigen that is widely expressed among human solid tumors. Anti-B7-H3 mouse monoclonal antibody 8H9 has been successfully used for radioimmunotherapy for patients with B7-H3(+) tumors. We present the humanization, affinity maturation, and epitope mapping of 8H9 based on structure determination, modeling, and yeast display methods. The crystal structure of ch8H9 Fab fragment was solved to 2.5-Å resolution and used as a template for humanization. By displaying the humanized 8H9 single chain Fv (scFv) on the surface of yeast, the affinity was matured by sequential random mutagenesis and fluorescence-activated cell sorting. Six mutations (three in the complementarity-determining region and three in the framework regions) were identified and incorporated into an affinity-matured humanized 8H9 construct (hu8H9-6m) and an affinity-matured chimeric 8H9 construct (ch8H9-6m). The hu8H9-6m scFv had a 160-fold improvement in affinity (0.9 nm KD) compared with parental hu8H9 scFv (144 nm KD). The IgG formats of ch8H9-6m and hu8H9-6m (nanomolar to subnanomolar KD) had 2-9-fold enhancements in affinity compared with their parental forms, potent in vitro antibody-dependent cell-mediated cytotoxicity (0.1-0.3 μg/ml EC50), and high tumor uptake in mouse xenografts. Based on in silico docking studies and experimental validation, the molecular epitope of 8H9 was determined to be dependent on the FG loop of B7-H3, a region critical to its function in immunologic blockade and unique among anti-B7-H3 antibodies published to date. PMID:26487718

  9. Ozone-vegetation interaction in the Earth system: implications for air quality, ecosystems and agriculture

    NASA Astrophysics Data System (ADS)

    Tai, A. P. K.; Lombardozzi, D.; Val Martin, M.; Heald, C. L.

    2015-12-01

    Surface ozone is one of the most significant air pollutants due to its damaging effects not only on human health, but also on vegetation and crop productivity. Chronic ozone exposure has been shown to reduce photosynthesis and interfere with gas exchange in plants, which in turn affect the surface energy balance, carbon sink and other biogeochemical fluxes. Ozone damage on vegetation can thus have major ramifications on climate and atmospheric composition, including possible feedbacks onto ozone itself (see figure) that are not well understood. The damage of ozone on crops has been well documented, but a mechanistic understanding is not well established. Here we present several results pertaining to ozone-vegetation interaction. Using the Community Earth System Model, we find that inclusion of ozone damage on plants reduces the global land carbon sink by up to 5%, while simulated ozone is modified by -20 to +4 ppbv depending on the relative importance of competing mechanisms in different regions. We also perform a statistical analysis of multidecadal global datasets of crop yields, agroclimatic variables and ozone exposures to characterize the spatial variability of crop sensitivity to ozone and temperature extremes, specifically accounting for the confounding effect of ozone-temperature covariation. We find that several crops exhibit stronger sensitivity to ozone than found by previous field studies, with a strong anticorrelation between the sensitivity and average ozone levels that reflects biological adaptive ozone resistance. Our results show that a more complete understanding of ozone-vegetation interaction is necessary to derive more realistic future projections of climate, air quality and agricultural production, and thereby to formulate optimal strategies to safeguard public health and food security.

  10. Tentative critical levels of tropospheric ozone for agricultural crops in Japan

    NASA Astrophysics Data System (ADS)

    Yonekura, T.

    2010-12-01

    Ground level ozone concentrations have increased year by year in Japan. High ozone concentrations have been known to affect growth and yield of agricultural crops. In the US and Europe, much effort has been directed to establish regulatory policies such as secondary air quality standard and critical levels to protect vegetation against ozone. On the contrary, in Japan, there is a few data of agricultural crops sensitivity to ozone. Furthermore, there is no information about the ozone risk of agricultural crop loss by based on ozone index (e.g. AOT40, SUM06, W126)-crop response relationship, yet. The objects of our research are: (1) to screen sensitivity of ozone on 10 crops cultivated in urban area in Japan. (2) to establish critical levels of ozone for protecting agricultural crops based on ozone index-crop response relationship. The 10 Japanese agricultural crops such as Japanese rice, Hanegi (Welsh onion), Shungiku (Crown daisy), Saradana (Lettus), Hatsukadaikon (Radish), Kokabu (Small Turnip), Santosai (Chinese cabbage), Tasai (Spinach mustard), Komatsuna (Japanese mustard spinach) and Chingensai (Bok Choy), were fumigated to three levels of ozone (clean air (< 5 ppbv), ambient level of ozone, 1.5 times ambient ozone) in open-top chambers during 30 to 120 days. Those experiments were repeated five times during two growing season. Throughout the experimental period, the growth or yield were measured, and the relationship between growth (or yield) and ozone index was examined. As a result, the influences of ozone on growth or yield were different among 10 crops. Relatively good correlations of coefficients of determination (r2) for linear regressions to growth or yield were obtained with “8h means” and “AOT40” rather than “SUM00”, “SUM06” and “W126”. Critical level for 10 crops in terms of an AOT40 were 1.1 to 2.1 ppm h per month. The ozone sensitive crop in our study was sound to be 1.0 ppm h per month in AOT40.

  11. Desorption of dimethylformamide from Zn4O(C8H4O4)3 framework

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Hu, Yun Hang

    2011-02-01

    Both dimethylformamide (DMF) and diethylformamide (DEF) are important solvents for the synthesis of Zn4O(C8H4O4)3 framework (MOF-5). It is generally recognized that DMF molecules can be completely displaced by CH2Cl2 during the synthesis of MOF-5. Herein, however, it was found that the DMF molecules inside the pores of the MOF-5 framework cannot be displaced by CH2Cl2. The desorption of the DMF molecules from the pores, which requires a temperature of 100 °C or above, is the first order with activation energy of 56.38 kJ/mol. In contrast, DEF molecules can be completely displaced by CH2Cl2 during the synthesis of MOF-5, because DEF molecules cannot penetrate into the pores of the MOF-5 paste.

  12. [Correlation Analysis Between Characteristics of VOCs and Ozone Formation Potential in Summer in Nanjing Urban District].

    PubMed

    Yang, Xiao-xiao; Tang, Li-li; Zhang, Yun-jiang; Mu, Ying-feng; Wang, Ming; Chen, Wen-tai; Zhou, Hong-cang; Hua, Yan; Jiang, Rong-xin

    2016-02-15

    Volatile organic compounds (VOCs) is an important precursor of photochemical ozone pollution (O3) in the atmosphere. Their concentration variation directly affects the characteristics of the ozone pollution. The concentration, speciation of VOCs, ozone and its precursors in Nanjing were analyzed and measured using online gas detection systems in August 2013. VOCs/NOx discriminant method was used to get the sensitive control factors of ozone. The results showed that the averaged volume fraction of VOCs was 52. 05 x 10(-9), and the largest one reached 200 x 10(-9) in Nanjing urban district. The order of volume fraction of each species VOCs was alkane > oxygen-containing VOCs > alkene > aromatics. The averaged concentration of ozone was 76.5 microg x m(-1) and the exceeding concentration of hourly standard was 5.9%. The change trends of ozone precursors VOCs and NOx were basically identical and Ozone showed the obvious negative correlation during the period of high concentrations of ozone. There were some differences in the concentrations of the same VOCs in different ozone concentration periods. The ozone generation in Nanjing urban district was sensitive to VOCs, and Nanjing belonged to VOCs control area in summer. PMID:27363129

  13. Impact of cabin ozone concentrations on passenger reported symptoms in commercial aircraft.

    PubMed

    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.

  14. [Correlation Analysis Between Characteristics of VOCs and Ozone Formation Potential in Summer in Nanjing Urban District].

    PubMed

    Yang, Xiao-xiao; Tang, Li-li; Zhang, Yun-jiang; Mu, Ying-feng; Wang, Ming; Chen, Wen-tai; Zhou, Hong-cang; Hua, Yan; Jiang, Rong-xin

    2016-02-15

    Volatile organic compounds (VOCs) is an important precursor of photochemical ozone pollution (O3) in the atmosphere. Their concentration variation directly affects the characteristics of the ozone pollution. The concentration, speciation of VOCs, ozone and its precursors in Nanjing were analyzed and measured using online gas detection systems in August 2013. VOCs/NOx discriminant method was used to get the sensitive control factors of ozone. The results showed that the averaged volume fraction of VOCs was 52. 05 x 10(-9), and the largest one reached 200 x 10(-9) in Nanjing urban district. The order of volume fraction of each species VOCs was alkane > oxygen-containing VOCs > alkene > aromatics. The averaged concentration of ozone was 76.5 microg x m(-1) and the exceeding concentration of hourly standard was 5.9%. The change trends of ozone precursors VOCs and NOx were basically identical and Ozone showed the obvious negative correlation during the period of high concentrations of ozone. There were some differences in the concentrations of the same VOCs in different ozone concentration periods. The ozone generation in Nanjing urban district was sensitive to VOCs, and Nanjing belonged to VOCs control area in summer.

  15. Impact of cabin ozone concentrations on passenger reported symptoms in commercial aircraft.

    PubMed

    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

  16. Changes in the Vertical Distribution of Ozone Over Canada From Ozonesondes: 1980-2001

    NASA Astrophysics Data System (ADS)

    Wardle, D. I.; Tarasick, D. W.; Fioletov, V. E.; Kerr, J. B.; Davies, J.

    2005-12-01

    Measurements of the vertical profile of ozone concentration using balloon-borne ECC ozonesondes have been made weekly since 1980 at several sites in Canada (Edmonton, Goose Bay, Churchill and Resolute), since 1987 at Alert and since 1992 at Eureka. Previous analyses of ozone trends over Canada have shown strong negative trends in tropospheric ozone. Here, with data up to the end of 2001, we find that while for the 1980-2001 period the overall linear trends are primarily negative, both in tropospheric and stratospheric ozone, when the data for 1991-2001 only are considered, the trends are positive, even in the lower stratosphere. When the time series are compared with previously reported trends (to 1993), it is evident that ozone has rebounded at all levels below about 63 hPa. These differences do not appear to be related to changes in tropopause height, as the average height of the tropopause (as measured over the ozonesonde stations) has not changed over either the 22-year or the 11-year period. Nevertheless, comparison with another dynamical indicator, the wintertime frequency of occurrence of laminae in the ozone profile, suggests that this rebound may be partly a result of small changes in the atmospheric circulation, rather than a recovery of the ozone layer from halocarbon-induced depletion. The long-term trends in average tropospheric ozone concentrations over Canada are similar to corresponding lower stratospheric trends, and tropospheric ozone levels show significant correlation with lower stratospheric ozone amounts.

  17. 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

  18. Tropospheric ozone and ozone profiles retrieved from GOME-2 and their validation

    NASA Astrophysics Data System (ADS)

    Miles, G. M.; Siddans, R.; Kerridge, B. J.; Latter, B. G.; Richards, N. A. D.

    2015-01-01

    This paper describes and assesses the performance of the RAL (Rutherford Appleton Laboratory) ozone profile retrieval scheme for the Global Ozone Monitoring Experiment 2 (GOME-2) with a focus on tropospheric ozone. Developments to the scheme since its application to GOME-1 measurements are outlined. These include the approaches developed to account sufficiently for UV radiometric degradation in the Hartley band and for inadequacies in knowledge of instrumental parameters in the Huggins bands to achieve the high-precision spectral fit required to extract information on tropospheric ozone. The assessment includes a validation against ozonesondes (sondes) sampled worldwide over 2 years (2007-2008). Standard deviations of the ensemble with respect to the sondes are considerably lower for the retrieved profiles than for the a priori, with the exception of the lowest subcolumn. Once retrieval vertical smoothing (averaging kernels) has been applied to the sonde profiles there is a retrieval bias of 6% (1.5 DU) in the lower troposphere, with smaller biases in the subcolumns above. The bias in the troposphere varies with latitude. The retrieval underestimates lower tropospheric ozone in the Southern Hemisphere (SH) (15-20% or ~ 1-3 DU) and overestimates it in the Northern Hemisphere (NH) (10% or 2 DU). The ability of the retrieval to reflect the geographical distribution of lower tropospheric ozone, globally (rather than just ozonesonde launch sites) is demonstrated by comparison with the chemistry transport model TOMCAT. For a monthly mean of cloud-cleared GOME-2 pixels, a correlation of 0.66 is found between the retrieval and TOMCAT sampled accordingly, with a bias of 0.7 Dobson Units. GOME-2 estimates higher concentrations in NH pollution centres but lower ozone in the Southern Ocean and South Pacific, which is consistent with the comparison to ozonesondes.

  19. 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.; Nielsen, J. E.; Pawson, S.; Stolarski, R. S.; Velders, G. J. M.

    2008-01-01

    Ozone depletion by chlorofluorocarbons (CFCs) was first proposed by Molina and Rowland in their 1974 Nature paper. Since that time, the sci entific connection between ozone losses and CFCs and other ozone depl eting substances (ODSs) has been firmly established with laboratory m easurements, atmospheric observations, and modeling research. This science research led to the implementation of international agreements t hat largely stopped the production of ODSs. In this study we use a fu lly-coupled radiation-chemical-dynamical model to simulate a future world where ODSs were never regulated and ODS production grew at an ann ual rate of 3%. In this "world avoided" simulation 1.7 % of the globa lly-average column ozone is destroyed by 2020, and 67% is destroyed b y 2065 in comparison to 1980. Large ozone depletions in the polar region become year-round rather than just seasonal as is currently observ ed 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 strat osphere remain constant until about 2053 and then collapse to near ze ro by 2058 as a result of heterogeneous chemical processes (as curren tly 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 radiation increa ses, more than doubling the erythemal radiation in the northern summer midlatitudes by 2060.

  20. Ozone, Electrostatic Precipitators, and Particle Number Concentrations: Correlations Observed in a Real Office during Working Hours.

    PubMed

    Xiang, Jianbang; Weschler, Charles J; Mo, Jinhan; Day, Drew; Zhang, Junfeng; Zhang, Yinping

    2016-09-20

    This study investigates the impacts of outdoor and indoor ozone concentrations, ESP operation and occupancy on particle number concentrations within a modern office in Changsha, China. The office's one-pass air handling system contains a mini-bag filter (MERV 12) followed by an electrostatic precipitator (ESP) and high efficiency particulate air (HEPA) filter. Over a five-week period the system was operated either without the ESP (Stage 1, first-third week) or with the ESP (Stage 2, fourth and fifth week). Ozone and particle number concentrations were measured on working days. During both stages, indoor ozone and particle number concentrations tracked the outdoor ozone concentration. When operating, the ESP produced approximately 29 mg h(-1) of ozone, increasing supply air ozone by 15 ppb and steady-state indoor ozone by about 3 ppb. Occupancy tended to decrease indoor ozone and increase particle levels. During occupancy, indoor particle levels were low (∼2600 particle/cm(3)) when the supply air ozone level was less than 18 ppb. Above this threshold, the supply air ozone concentration and indoor particle number concentration were linearly related, and ESP operation increased the average indoor particle level by about 22 000 particles/cm(3). The implications for worker exposure to both ozone and particles are discussed. PMID:27571436

  1. Ozone, Electrostatic Precipitators, and Particle Number Concentrations: Correlations Observed in a Real Office during Working Hours.

    PubMed

    Xiang, Jianbang; Weschler, Charles J; Mo, Jinhan; Day, Drew; Zhang, Junfeng; Zhang, Yinping

    2016-09-20

    This study investigates the impacts of outdoor and indoor ozone concentrations, ESP operation and occupancy on particle number concentrations within a modern office in Changsha, China. The office's one-pass air handling system contains a mini-bag filter (MERV 12) followed by an electrostatic precipitator (ESP) and high efficiency particulate air (HEPA) filter. Over a five-week period the system was operated either without the ESP (Stage 1, first-third week) or with the ESP (Stage 2, fourth and fifth week). Ozone and particle number concentrations were measured on working days. During both stages, indoor ozone and particle number concentrations tracked the outdoor ozone concentration. When operating, the ESP produced approximately 29 mg h(-1) of ozone, increasing supply air ozone by 15 ppb and steady-state indoor ozone by about 3 ppb. Occupancy tended to decrease indoor ozone and increase particle levels. During occupancy, indoor particle levels were low (∼2600 particle/cm(3)) when the supply air ozone level was less than 18 ppb. Above this threshold, the supply air ozone concentration and indoor particle number concentration were linearly related, and ESP operation increased the average indoor particle level by about 22 000 particles/cm(3). The implications for worker exposure to both ozone and particles are discussed.

  2. An evaluation of ozone exposure metrics for a seasonally drought-stressed ponderosa pine ecosystem.

    PubMed

    Panek, Jeanne A; Kurpius, Meredith R; Goldstein, Allen H

    2002-01-01

    Ozone stress has become an increasingly significant factor in cases of forest decline reported throughout the world. Current metrics to estimate ozone exposure for forest trees are derived from atmospheric concentrations and assume that the forest is physiologically active at all times of the growing season. This may be inaccurate in regions with a Mediterranean climate, such as California and the Pacific Northwest, where peak physiological activity occurs early in the season to take advantage of high soil moisture and does not correspond to peak ozone concentrations. It may also misrepresent ecosystems experiencing non-average climate conditions such as drought years. We compared direct measurements of ozone flux into a ponderosa pine canopy with a suite of the most common ozone exposure metrics to determine which best correlated with actual ozone uptake by the forest. Of the metrics we assessed, SUM0 (the sum of all daytime ozone concentrations > 0) best corresponded to ozone uptake by ponderosa pine, however the correlation was only strong at times when the stomata were unconstrained by site moisture conditions. In the early growing season (May and June). SUM0 was an adequate metric for forest ozone exposure. Later in the season, when stomatal conductance was limited by drought. SUM0 overestimated ozone uptake. A better metric for seasonally drought-stressed forests would be one that incorporates forest physiological activity, either through mechanistic modeling, by weighting ozone concentrations by stomatal conductance, or by weighting concentrations by site moisture conditions. PMID:11843543

  3. 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.

  4. Long-term total ozone response caused by extra-terrestrial factors

    NASA Astrophysics Data System (ADS)

    Krivolutsky, A.; Knyazeva, N.; Perejaslova, G.; Bazilevskaya, G.; Nazarova, M.

    The observations of solar proton fluxes from boards of "Meteor", GOES satellites, galactic cosmic ray fluxes measured in the stratosphere by balloons, solar radio irradiance and total ozone records (ground based and TOMS data) for 1960-2000 period, has been used to investigate spatial and temporal structure of total ozone response to cosmic influence. Linear simple and multiply regression analysis has been used in our study. Yearly averaged data were used for analysis to e timates long-t erm effects in ozone response. Ozone data were grouped in different latitudinal belts of 100 width for Northern Hemisphere from equator to 800 N. Simple linear regression analysis for individual cosmic factors revealed negative total ozone response (in accordance to the conception of ozone destruction by additional amount of NOx produced by solar protons in the atmosphere of the Earth)0 for the years of strong solar proton events for latitudes which were higher than 45 N However, positive response for lower latitudes was found, when the same regression method was used. In the case of GCR influence on ozone the decadal response of ozone was revealed at high latitudes, which was in phase with galactic cosmic ray flux and in contract to the mentioned conception of ozone destruction by the NOx . Multiply regression analysis gave the long-term ozone variation of cosmic nature similar to real variations of total ozone.

  5. Ozone Depletion by Hydrofluorocarbons

    NASA Astrophysics Data System (ADS)

    Hurwitz, M.; Fleming, E. L.; Newman, P. A.; Li, F.; Mlawer, E. J.; Cady-Pereira, K. E.; Bailey, R.

    2015-12-01

    Hydrofluorocarbons (HFCs) are second-generation replacements for the chlorofluorocarbons (CFCs), halons and other substances that caused the 'ozone hole'. Atmospheric concentrations of HFCs are projected to increase dramatically in the coming decades. Coupled chemistry-climate simulations forced by these projections show that HFCs will impact the global atmosphere in 2050. As strong radiative forcers, HFCs modulate atmospheric temperature, thereby changing ozone-destroying catalytic cycles and enhancing the stratospheric circulation. These changes lead to a weak depletion of stratospheric ozone. Sensitivity simulations with the NASA Goddard Space Flight Center (GSFC) 2D model show that HFC-125 is the most important contributor to atmospheric change in 2050, as compared with HFC-23, HFC-32, HFC-134a and HFC-143a. Incorporating the interactions between chemistry, radiation and dynamics, for a likely 2050 climate, ozone depletion potentials (ODPs) for HFCs range from 4.3x10-4 to 3.5x10-2; previously HFCs were assumed to have negligible ODPs since these species lack chlorine or bromine atoms. The ozone impacts of HFCs are further investigated with the Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM). The GEOSCCM is a three-dimensional, fully coupled ocean-atmosphere model with interactive stratospheric chemistry. Sensitivity simulations in which CO2, CFC-11 and HCFC-22 are enhanced individually are used as proxies for the atmospheric response to the HFC concentrations expected by the mid-21st century. Sensitivity simulations provide quantitative estimates of the impacts of these greenhouse gases on global total ozone, and can be used to assess their effects on the recovery of Antarctic ozone.

  6. Have primary emission reduction measures reduced ozone across Europe? An analysis of European rural background ozone trends 1996-2005

    NASA Astrophysics Data System (ADS)

    Wilson, R. C.; Fleming, Z. L.; Monks, P. S.; Clain, G.; Henne, S.; Konovalov, I. B.; Szopa, S.; Menut, L.

    2012-01-01

    National and European legislation over the past 20 yr, and the modernisation or removal of industrial sources, have significantly reduced European ozone precursor emissions. This study quantifies observed and modelled European ozone annual and seasonal linear trends from 158 harmonised rural background monitoring stations over a constant time period of a decade (1996-2005). Mean ozone concentrations are investigated, in addition to the ozone 5th percentiles as a measure of the baseline or background conditions, and the 95th percentiles that are representative of the peak concentration levels. This study aims to characterise and quantify surface European ozone concentrations and trends and assess the impact of the changing anthropogenic emission tracers on the observed and modelled trends. Significant (p<0.1) positive annual trends in ozone mean, 5th and 95th percentiles are observed at 54 %, 52 % and 45 % of sites respectively (85 sites, 82 sites and 71 sites). Spatially, sites in central and north-western Europe tend to display positive annual ozone trends in mean, 5th and 95th percentiles. Significant negative annual trends in ozone mean 5th and 95th percentiles are observed at 11 %, 12 % and 12 % of sites respectively (18 sites, 19 sites and 19 sites) which tend to be located in the eastern and south-western extremities of Europe. European-averaged annual trends have been calculated from the 158 sites in this study. Overall there is a net positive annual trend in observed ozone mean (0.16±0.02 ppbv yr-1 (2σ error)), 5th (0.13±0.02 ppbv yr-1) and 95th (0.16±0.03 ppbv yr-1) percentiles, representative of positive trends in mean, baseline and peak ozone. Assessing the sensitivity of the derived overall trends to the constituent years shows that the European heatwave year of 2003 has significant positive influence and 1998 the converse effect; demonstrating the masking effect of inter-annual variability on decadal based ozone trends. The European scale 3-D CTM

  7. [Isolation and amplification cDNA of 8H07 gene conservative region of nematode Heterodera schachtii with high relationship to its rape homolog].

    PubMed

    Tsyhankova, V A; Andrusevych, Ia V; Ponomarenko, S P; Halkin, A P; Blium, Ia B

    2012-01-01

    Original method of small regulatory si/miRNA isolation from plant cells was elaborated. PCR amplification of fragment cDNA 8H07 nematode Heterodera schachtii gene was carried out. Using Northern-blot method hybridization of plant si/miRNA with cDNA fragment of conservative region 8H07 gene the presence of their high homology is found out. The amplified cDNA fragment of nematode 8H07 gene in future will be used for creation recombinant gene with complementary antisense dsRNA sequence for increasing resistance of rape plants to parasitic nematodes.

  8. Children's Models of the Ozone Layer and Ozone Depletion.

    ERIC Educational Resources Information Center

    Christidou, Vasilia; Koulaidis, Vasilis

    1996-01-01

    The views of 40 primary students on ozone and its depletion were recorded through individual, semi-structured interviews. The data analysis resulted in the formation of a limited number of models concerning the distribution and role of ozone in the atmosphere, the depletion process, and the consequences of ozone depletion. Identifies five target…

  9. Ozone Contamination in Aircraft Cabins. Appendix A: Ozone toxicity

    NASA Technical Reports Server (NTRS)

    Melton, C. E.

    1979-01-01

    The recommendation that at various altitudes the amount of air with which ozone has mixed changes, thus changing the volume per volume relationship is discussed. The biological effects of ozone on human health and the amount of ozone necessary to produce symptoms were investigated.

  10. 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 ...

  11. Detecting the Recovery of the Antarctic Ozone Hole

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Kawa, S. Randolph; Montzka, Steve

    2004-01-01

    The Antarctic ozone hole develops each year and culminates by early Spring. Antarctic ozone values have been monitored since 1979 using satellite observations from the TOMS instrument. The severity of the hole has been assessed from TOMS using the minimum total ozone value from the October monthly mean (depth of the hole) and by calculating the average size during the September-October period. Ozone is mainly destroyed by halogen catalytic cycles, and these losses are modulated by temperature variations in the collar of the polar lower stratospheric vortex. In this presentation, we show the relationships of halogens and temperature to both the size and depth of the hole. 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 will show estimates of both when the ozone hole will begin to show first signs of recovery, and when the hole will fully recover to pre-1980 levels.

  12. Perspectives on African Ozone from Sondes, Dobson and Aircraft Measurements

    NASA Technical Reports Server (NTRS)

    Thompson, A. M.; Witte, J. C.; Chatfield, R. B.; Diab, R. D.; Thouret, V.; Sauvage, B.

    2004-01-01

    We have been studying variability in ozone over Africa using data from ozonesondes (vertical profiles from surface to stratosphere), aircraft (the MOZAIC dataset with cruise altitude and landing/takeoff profiles) and the ground (Dobson spectrophotometer total ozone column measurement). The following may give context for ozone investigations during AMMA: 1. Total ozone measurements since 1989 show considerable variability in mean value among the African stations in Algeria, Kenya, Egypt, South Africa, as well as in seasonal cycles and year-to-year. Trends are not evident. 2. The impacts of convection, stratospheric injection, biomass burning and lightning appear in ozone sounding profile data. Time-series analysis and case studies point to periodic influences of long-range interactions with the Atlantic ("ozone paradox," wave-one") and Indian Oceans. 3. Tropospheric ozone variations, observed in tropospheric profiles and integrated column amount, follow general seasonal patterns but short- term variability is so strong that simple averages are inadequate for describing "climatology" and statistical classification approaches may be required.

  13. Synoptic and meteorological drivers of extreme ozone concentrations over Europe

    NASA Astrophysics Data System (ADS)

    Otero, Noelia Felipe; Sillmann, Jana; Schnell, Jordan L.; Rust, Henning W.; Butler, Tim

    2016-04-01

    The present work assesses the relationship between local and synoptic meteorological conditions and surface ozone concentration over Europe in spring and summer months, during the period 1998-2012 using a new interpolated data set of observed surface ozone concentrations over the European domain. Along with local meteorological conditions, the influence of large-scale atmospheric circulation on surface ozone is addressed through a set of airflow indices computed with a novel implementation of a grid-by-grid weather type classification across Europe. Drivers of surface ozone over the full distribution of maximum daily 8-hour average values are investigated, along with drivers of the extreme high percentiles and exceedances or air quality guideline thresholds. Three different regression techniques are applied: multiple linear regression to assess the drivers of maximum daily ozone, logistic regression to assess the probability of threshold exceedances and quantile regression to estimate the meteorological influence on extreme values, as represented by the 95th percentile. The relative importance of the input parameters (predictors) is assessed by a backward stepwise regression procedure that allows the identification of the most important predictors in each model. Spatial patterns of model performance exhibit distinct variations between regions. The inclusion of the ozone persistence is particularly relevant over Southern Europe. In general, the best model performance is found over Central Europe, where the maximum temperature plays an important role as a driver of maximum daily ozone as well as its extreme values, especially during warmer months.

  14. "OZONE SOURCE APPORTIONMENT IN CMAQ'

    EPA Science Inventory

    Ozone source attribution has been used to support various policy purposes including interstate transport (Cross State Air Pollution Rule) by U.S. EPA and ozone nonattainment area designations by State agencies. Common scientific applications include tracking intercontinental tran...

  15. Ozone Minimums, 1979 to 2013

    NASA Video Gallery

    Minimum concentration of ozone in the southern hemisphere for each year from 1979-2013 (there is no data from 1995). Each image is the day of the year with the lowest concentration of ozone. A grap...

  16. Changes in US background ozone due to global anthropogenic emissions from 1970 to 2020

    NASA Astrophysics Data System (ADS)

    Nopmongcol, Uarporn; Jung, Jaegun; Kumar, Naresh; Yarwood, Greg

    2016-09-01

    Estimates of North American and US Background (NAB and USB) ozone (O3) are critical in setting and implementing the US National Ambient Air Quality Standards (NAAQS) and therefore influence population exposure to O3 across the US. NAB is defined as the O3 concentration in the absence of anthropogenic O3 precursor emissions from North America whereas USB excludes anthropogenic emissions inside the US alone. NAB and USB vary geographically and with time of year. Analyses of O3 trends at rural locations near the west coast suggest that background O3 is rising in response to increasing non-US emissions. As the O3 NAAQS is lowered, rising background O3 would make attaining the NAAQS more difficult. Most studies of changing US background O3 have inferred trends from observations whereas air quality management decisions tend to rely on models. Thus, it is important that the models used to develop O3 management strategies are able to represent the changes in background O3 in order to increase confidence that air quality management strategies will succeed. We focus on how changing global emissions influence USB rather than the effects of inter-annual meteorological variation or long-term climate change. We use a regional model (CAMx) nested within a global model (GEOS-Chem) to refine our grid resolution over high terrain in the western US and near US borders where USB tends to be higher. We determine USB from CAMx simulations that exclude US anthropogenic emissions. Over five decades, from 1970 to 2020, estimated USB for the annual fourth highest maximum daily 8-h average O3 (H4MDA8) in the western US increased from mostly in the range of 40-55 ppb to 45-60 ppb, but remained below 45 ppb in the eastern US. USB increases in the southwestern US are consistent with rising emissions in Asia and Mexico. USB decreases in the northeast US after 1990 follow declining Canadian emissions. Our results show that the USB increases both for the top 30 MDA8 days and the H4MDA8 (the former

  17. Stratospheric Ozone Predictions For The Late 21st Century

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    Simulations of ozone evolution from 1960 until ~2100 from chemistry climate models (CCMs) that participated in CCMVal-2 are broadly consistent in that stratospheric ozone increases as chlorofluorcarbons decrease and the stratosphere cools (which affects the rate of temperature dependent loss processes), however, details of the projections vary significantly. Differences in the ozone response to specified changes in chlorine containing source gases dominate during the first half of the integrations. For example, from 1980 to 2000, chlorine change is by far the most important cause of ozone change, and the CCMs produce changes in the 60S-60N average column ozone that range between -3 DU and -17 DU. In the second half of the 21st century climate change is primarily responsible for ozone change. By 2080 the CCMs produce changes in the 60S-60N average upper stratospheric ozone column that range from 4 DU to 10 DU. The CCM range of differences is due to differences in both composition and upper stratospheric temperature. Ozone loss processes each have their own temperature sensitivity, and the net sensitivity of ozone to temperature change in each CCM depends on the relative importance of each loss process; this depends on the composition and temperature for the baseline atmosphere. In the lower stratosphere, climate change affects ozone evolution through changes in photochemical reaction rates due to stratospheric cooling and through circulation differences affecting transport of ozone and other trace gases. These are not separable using an approach such as multiple linear regression because changes in circulation and temperature have the same time dependence after accounting for contributions due to chlorine change. Recent attention has focused on similarity of the CCMs in that all predict a speed-up of the Brewer Dobson circulation. However, differences in the magnitude of the speed-up, differences in horizontal mixing and differences in the photochemical response to

  18. Estimating the effects of increased urbanization on surface meteorology and ozone concentrations in the New York City metropolitan region

    NASA Astrophysics Data System (ADS)

    Civerolo, Kevin; Hogrefe, Christian; Lynn, Barry; Rosenthal, Joyce; Ku, Jia-Yeong; Solecki, William; Cox, Jennifer; Small, Christopher; Rosenzweig, Cynthia; Goldberg, Richard; Knowlton, Kim; Kinney, Patrick

    Land use and pollutant emission changes can have significant impacts on air quality, regional climate, and human health. Here we describe a modeling study aimed at quantifying the potential effects of extensive changes in urban land cover in the New York City (NYC), USA metropolitan region on surface meteorology and ozone (O 3) concentrations. The SLEUTH land-use change model was used to extrapolate urban land cover over this region from "present-day" (ca. 1990) conditions to a future year (ca. 2050), and these projections were subsequently integrated into meteorological and air quality simulations. The development of the future-year land-use scenario followed the narrative of the "A2" scenario described by the Intergovernmental Panel on Climate Change (IPCC), but was restricted to the greater NYC area. The modeling system consists of the Penn State/NCAR MM5 mesoscale meteorological model; the Sparse Matrix Operator Kernal Emissions processing system; and the US EPA Community Multiscale Air Quality model, and simulations were performed for two 18-day episodes, one near-past and one future. Our results suggest that extensive urban growth in the NYC metropolitan area has the potential to increase afternoon near-surface temperatures by more than 0.6 °C and planetary boundary layer (PBL) heights by more than 150 m, as well as decrease water vapor mixing ratio by more than 0.6 g kg -1, across the NYC metropolitan area, with the areal extent of all of these changes generally coinciding with the area of increased urbanization. On the other hand, the impacts of these land use changes on ozone concentrations are more complex. Simulation results indicate that future changes in urbanization, with emissions held constant, may lead to increases in episode-average O 3 levels by about 1-5 ppb, and episode-maximum 8 h O 3 levels by more than 6 ppb across much of the NYC area. However, spatial patterns of ozone changes are heterogeneous and also indicate the presence of areas with

  19. Winter rain and summer ozone: a predictive relationship.

    PubMed

    Sandberg, J S; Basso, M J; Okin, B A

    1978-06-01

    Insights from dendrochronology have provided a new seasonal predictor for air pollution meteorology. In the San Francisco Bay Area summer ozone excesses over the federal ozone standard are correlated (correlation coefficient r = .87) with precipitation for the two preceding winters, a factor related to tree-ring width in a precipitation-stressed climate. The hypothesis that reactive hydrocarbon emissions from vegetative biomass affects these ozone excesses was supported by a similar correlation between summer hydrocarbon average maximums and the two-winter precipitation factor, reaching r = .88 at suburban stations. A weak tendency for hot summers to follow wet winters (in 16 years of California data) explains only a minor part of the ozone-rain relationship in multiple correlations.

  20. Developing a predictive tropospheric ozone model for Tabriz

    NASA Astrophysics Data System (ADS)

    Khatibi, Rahman; Naghipour, Leila; Ghorbani, Mohammad A.; Smith, Michael S.; Karimi, Vahid; Farhoudi, Reza; Delafrouz, Hadi; Arvanaghi, Hadi

    2013-04-01

    Predictive ozone models are becoming indispensable tools by providing a capability for pollution alerts to serve people who are vulnerable to the risks. We have developed a tropospheric ozone prediction capability for Tabriz, Iran, by using the following five modeling strategies: three regression-type methods: Multiple Linear Regression (MLR), Artificial Neural Networks (ANNs), and Gene Expression Programming (GEP); and two auto-regression-type models: Nonlinear Local Prediction (NLP) to implement chaos theory and Auto-Regressive Integrated Moving Average (ARIMA) models. The regression-type modeling strategies explain the data in terms of: temperature, solar radiation, dew point temperature, and wind speed, by regressing present ozone values to their past values. The ozone time series are available at various time intervals, including hourly intervals, from August 2010 to March 2011. The results for MLR, ANN and GEP models are not overly good but those produced by NLP and ARIMA are promising for the establishing a forecasting capability.

  1. Winter rain and summer ozone: a predictive relationship.

    PubMed

    Sandberg, J S; Basso, M J; Okin, B A

    1978-06-01

    Insights from dendrochronology have provided a new seasonal predictor for air pollution meteorology. In the San Francisco Bay Area summer ozone excesses over the federal ozone standard are correlated (correlation coefficient r = .87) with precipitation for the two preceding winters, a factor related to tree-ring width in a precipitation-stressed climate. The hypothesis that reactive hydrocarbon emissions from vegetative biomass affects these ozone excesses was supported by a similar correlation between summer hydrocarbon average maximums and the two-winter precipitation factor, reaching r = .88 at suburban stations. A weak tendency for hot summers to follow wet winters (in 16 years of California data) explains only a minor part of the ozone-rain relationship in multiple correlations. PMID:17740697

  2. Tropospheric ozone distributions measured with an airborne laser absorption spectrometer

    NASA Technical Reports Server (NTRS)

    Menzies, R. T.; Shumate, M. S.

    1978-01-01

    Measurements of tropospheric ozone have been made in the southern and middle California regions and over the Pacific Ocean during two series of flights in February and May 1977. The data were obtained by using a laser absorption spectrometer, a nadir-viewing instrument which remotely measures the ozone column abundance between ground level and aircraft altitude by interacting with ozone at specific wavelengths near 9.5 microns. The measurements indicate significantly lower ozone abundances above the Mojave Desert region as compared with farm, forest, and urban areas. The average tropospheric column density was found to be 0.0027 atm cm/km over the California region and 0.0035 atm cm/km over the Pacific Ocean region 1000-2000 km west of the coast of Mexico.

  3. Approach to forecasting daily maximum ozone levels in St. Louis

    NASA Technical Reports Server (NTRS)

    Prior, E. J.; Schiess, J. R.; Mcdougal, D. S.

    1981-01-01

    Measurements taken in 1976 from the St. Louis Regional Air Pollution Study (RAPS) data base, conducted by EPA, were analyzed to determine an optimum set of air-quality and meteorological variables for predicting maximum ozone levels for each day in 1976. A 'leaps and bounds' regression analysis was used to identify the best subset of variables. Three particular variables, the 9 a.m. ozone level, the forecasted maximum temperature, and the 6-9 a.m. averaged wind speed, have useful forecasting utility. The trajectory history of air masses entering St. Louis was studied, and it was concluded that transport-related variables contribute to the appearance of very high ozone levels. The final empirical forecast model predicts the daily maximum ozone over 341 days with a standard deviation of 11 ppb, which approaches the estimated error.

  4. Dissociating Averageness and Attractiveness: Attractive Faces Are Not Always Average

    ERIC Educational Resources Information Center

    DeBruine, Lisa M.; Jones, Benedict C.; Unger, Layla; Little, Anthony C.; Feinberg, David R.

    2007-01-01

    Although the averageness hypothesis of facial attractiveness proposes that the attractiveness of faces is mostly a consequence of their averageness, 1 study has shown that caricaturing highly attractive faces makes them mathematically less average but more attractive. Here the authors systematically test the averageness hypothesis in 5 experiments…

  5. Ozone depletion by hydrofluorocarbons

    NASA Astrophysics Data System (ADS)

    Hurwitz, Margaret M.; Fleming, Eric L.; Newman, Paul A.; Li, Feng; Mlawer, Eli; Cady-Pereira, Karen; Bailey, Roshelle

    2015-10-01

    Atmospheric concentrations of hydrofluorocarbons (HFCs) are projected to increase considerably in the coming decades. Chemistry climate model simulations forced by current projections show that HFCs will impact the global atmosphere increasingly through 2050. As strong radiative forcers, HFCs increase tropospheric and stratospheric temperatures, thereby enhancing ozone-destroying catalytic cycles and modifying the atmospheric circulation. These changes lead to a weak depletion of stratospheric ozone. Simulations with the NASA Goddard Space Flight Center 2-D model show that HFC-125 is the most important contributor to HFC-related atmospheric change in 2050; its effects are comparable to the combined impacts of HFC-23, HFC-32, HFC-134a, and HFC-143a. Incorporating the interactions between chemistry, radiation, and dynamics, ozone depletion potentials (ODPs) for HFCs range from 0.39 × 10-3 to 30.0 × 10-3, approximately 100 times larger than previous ODP estimates which were based solely on chemical effects.

  6. Impacts of Ozone-vegetation Interactions and Biogeochemical Feedbacks on Atmospheric Composition and Air Quality Under Climate Change

    NASA Astrophysics Data System (ADS)

    Sadeke, M.; Tai, A. P. K.; Lombardozzi, D.; Val Martin, M.

    2015-12-01

    Surface ozone pollution is one of the major environmental concerns due to its damaging effects on human and vegetation. One of the largest uncertainties of future surface ozone prediction comes from its interaction with vegetation under a changing climate. Ozone can be modulated by vegetation through, e.g., biogenic emissions, dry deposition and transpiration. These processes are in turn affected by chronic exposure to ozone via lowered photosynthesis rate and stomatal conductance. Both ozone and vegetation growth are expected to be altered by climate change. To better understand these climate-ozone-vegetation interactions and possible feedbacks on ozone itself via vegetation, we implement an online ozone-vegetation scheme [Lombardozzi et al., 2015] into the Community Earth System Model (CESM) with active atmospheric chemistry, climate and land surface components. Previous overestimation of surface ozone in eastern US, Canada and Europe is shown to be reduced by >8 ppb, reflecting improved model-observation comparison. Simulated surface ozone is lower by 3.7 ppb on average globally. Such reductions (and improvements) in simulated ozone are caused mainly by lower isoprene emission arising from reduced leaf area index in response to chronic ozone exposure. Effects via transpiration are also potentially significant but require better characterization. Such findings suggest that ozone-vegetation interaction may substantially alter future ozone simulations, especially under changing climate and ambient CO2 levels, which would further modulate ozone-vegetation interactions. Inclusion of such interactions in Earth system models is thus necessary to give more realistic estimation and prediction of surface ozone. This is crucial for better policy formulation regarding air quality, land use and climate change mitigation. Reference list: Lombardozzi, D., et al. "The Influence of Chronic Ozone Exposure on Global Carbon and Water Cycles." Journal of Climate 28.1 (2015): 292-305.

  7. Tropospheric ozone measurements at the equatorial region (1980-1988)

    NASA Technical Reports Server (NTRS)

    Ilyas, Mohammad

    1994-01-01

    Results from surface ozone measurements at Penang (5.5 deg N, 100 deg E) over 1980-88 period are presented. The study indicates the ozone concentrations undergoing significant diurnal and seasonal variations. The peak concentration are observed at around mid-day (up to 35 nb) but the O3 concentration generally drops to zero level in the early evening and remains unchanged until mid-morning. Monthly-averaged daily 1-h average concentrations are generally small (4-13 nb) and decrease continually from the early part of the year to the end. Frequently, varying local weather conditions seem to influence the O3 concentrations.

  8. Have primary emission reduction measures reduced ozone across Europe? An analysis of European rural background ozone trends 1996-2005

    NASA Astrophysics Data System (ADS)

    Wilson, R. C.; Fleming, Z. L.; Monks, P. S.; Clain, G.; Henne, S.; Konovalov, I. B.; Szopa, S.; Menut, L.

    2011-06-01

    National and European legislation over the past 20 years, and the modernisation or removal of industrial sources, have significantly reduced European ozone precursor emissions. This study quantifies observed and modelled European ozone annual and seasonal linear trends from 158 harmonised rural background monitoring stations over a constant time period of a decade (1996-2005). Mean ozone concentrations are investigated, in addition to the ozone 5th percentiles as a measure of the baseline or background conditions, and the 95th percentiles that are representative of the peak concentration levels. This study aims to characterise and quantify surface European ozone concentrations and trends and assess the impact of the changing anthropogenic emission tracers on the observed and modelled trends. Significant (p < 0.1) positive annual trends in ozone mean, 5th and 95th percentiles are observed at 54 %, 52 % and 45 % of sites respectively (85 sites, 82 sites and 71 sites). Spatially, sites in Central and Northwestern Europe tend to display positive annual ozone trends in mean, 5th and 95th percentiles. Significant negative annual trends in ozone mean 5th and 95th percentiles are observed at 11 %, 12 % and 12 % of sites respectively (18 sites, 19 sites and 19 sites) which tend to be located in the eastern and south-western extremities of Europe. European-averaged annual trends have been calculated from the 158 sites in this study. Overall there is a net positive annual trend in observed ozone mean (0.16 ± 0.02 ppbv yr-1 2σ error)), 5th (0.13 ± 0.02 ppbv yr-1) and 95th (0.16 ± 0.03 ppbv yr-1) percentiles, representative of positive trends in mean, baseline and peak ozone. Assessing the sensitivity of the derived overall trends to the constituent years shows that the European heatwave year of 2003 has significant positive influence and 1998 the converse effect; demonstrating the masking effect of inter-annual variability on decadal based ozone trends. The European scale

  9. Mass and Ozone Fluxes from the Lowermost Stratosphere

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark R.; Olsen, Mark A.

    2004-01-01

    Net mass flux from the stratosphere to the troposphere can be computed from the heating rate along the 380K isentropic surface and the time rate of change of the mass of the lowermost stratosphere (the region between the tropopause and the 380K isentrope). Given this net mass flux and the cross tropopause diabatic mass flux, the residual adiabatic mass flux across the tropopause can also be estimated. These fluxes have been computed using meteorological fields from a free-running general circulation model (FVGCM) and two assimilation data sets, FVDAS, and UKMO. The data sets tend to agree that the annual average net mass flux for the Northern Hemisphere is about 1P10 kg/s. There is less agreement on the southern Hemisphere flux that might be half as large. For all three data sets, the adiabatic mass flux is computed to be from the upper troposphere into the lowermost stratosphere. This flux will dilute air entering from higher stratospheric altitudes. The mass fluxes are convolved with ozone mixing ratios from the Goddard 3D CTM (which uses the FVGCM) to estimate the cross-tropopause transport of ozone. A relatively large adiabatic flux of tropospheric ozone from the tropical upper troposphere into the extratropical lowermost stratosphere dilutes the stratospheric air in the lowermost stratosphere. Thus, a significant fraction of any measured ozone STE may not be ozone produced in the higher Stratosphere. The results also illustrate that the annual cycle of ozone concentration in the lowermost stratosphere has as much of a role as the transport in the seasonal ozone flux cycle. This implies that a simplified calculation of ozone STE mass from air mass and a mean ozone mixing ratio may have a large uncertainty.

  10. Ozone and cardiovascular injury.

    PubMed

    Srebot, Vera; Gianicolo, Emilio A L; Rainaldi, Giuseppe; Trivella, Maria Giovanna; Sicari, Rosa

    2009-06-24

    Air pollution is increasingly recognized as an important and modifiable determinant of cardiovascular diseases in urban communities. The potential detrimental effects are both acute and chronic having a strong impact on morbidity and mortality. The acute exposure to pollutants has been linked to adverse cardiovascular events such as myocardial infarction, heart failure and life-threatening arrhythmias. The long-terms effects are related to the lifetime risk of death from cardiac causes. The WHO estimates that air pollution is responsible for 3 million premature deaths each year. The evidence supporting these data is very strong nonetheless, epidemiologic and observational data have the main limitation of imprecise measurements. Moreover, the lack of clinical experimental models makes it difficult to demonstrate the individual risk. The other limitation is related to the lack of a clear mechanism explaining the effects of pollution on cardiovascular mortality. In the present review we will explore the epidemiological, clinical and experimental evidence of the effects of ozone on cardiovascular diseases. The pathophysiologic consequences of air pollutant exposures have been extensively investigated in pulmonary systems, and it is clear that some of the major components of air pollution (e.g. ozone and particulate matter) can initiate and exacerbate lung disease in humans 1. It is possible that pulmonary oxidant stress mediated by particulate matter and/or ozone (O3) exposure can result in downstream perturbations in the cardiovasculature, as the pulmonary and cardiovascular systems are intricately associated, and it is well documented that specific environmental toxins (such as tobacco smoke 2) introduced through the lungs can initiate and/or accelerate cardiovascular disease development. Indeed, several epidemiologic studies have proved that there is an association between PM and O3 and the increased incidence of cardiovascular morbidity and mortality 3. Most of the

  11. SAGE II Ozone Analysis

    NASA Technical Reports Server (NTRS)

    Cunnold, Derek; Wang, Ray

    2002-01-01

    Publications from 1999-2002 describing research funded by the SAGE II contract to Dr. Cunnold and Dr. Wang are listed below. Our most recent accomplishments include a detailed analysis of the quality of SAGE II, v6.1, ozone measurements below 20 km altitude (Wang et al., 2002 and Kar et al., 2002) and an analysis of the consistency between SAGE upper stratospheric ozone trends and model predictions with emphasis on hemispheric asymmetry (Li et al., 2001). Abstracts of the 11 papers are attached.

  12. Ozone in the southeastern United States: An observation-based model using measurements from the SEARCH network

    NASA Astrophysics Data System (ADS)

    Blanchard, C. L.; Hidy, G. M.; Tanenbaum, S.

    2014-05-01

    A generalized additive model (GAM) is used to examine the influence of meteorological factors, nitrogen oxides (NOx = NO + NO2), and non-methane hydrocarbons (NMOC) on daily peak 8-h ozone (O3) concentrations. Application to 2002-2011 monitoring data from the Southeastern Aerosol Research and Characterization (SEARCH) program showed sensitivity of peak 8-h O3 to morning concentrations of nitric oxide (NO) and nitrogen dioxide (NO2) and to afternoon concentrations of NO2 reaction products (NOz). Peak O3 decreased with increasing NO and increased with increasing NO2 concentrations, consistent with reactions involving O3, NO, and NO2. Ozone production efficiency (OPE), estimated from the modeled relation between peak 8-h O3 and afternoon NOz, was ˜40-100 percent higher at rural compared to urban sites. OPE was nonlinear at all sites, decreasing with increasing NOz concentration. The mean ratio of NOz/NOy showed a two-fold increase from urban to rural sites, associated with chemical aging in stagnant air masses from one day (urban sites) to two or more days (non-urban sites). Peak 8-h O3 concentrations in Atlanta were sensitive to concentrations of both non-biogenic NMOC and NOz. Non-urban Yorkville, Georgia, peak 8-h O3 concentrations were sensitive to NOz but not to non-biogenic NMOC concentrations. The results are consistent with expected NMOC and NOx sensitivity in urban and non-urban locales.

  13. Antarctic total ozone in 1958

    SciTech Connect

    Newman, P.A. )

    1994-04-22

    The Antarctic ozone hole results from catalytic destruction of ozone by chlorine radicals. The hole develops in August, reaches its full depth in early October, and is gone by early December of each year. Extremely low total ozone measurements were made at the Antarctic Dumont d'Urville station in 1958. These measurements were derived from spectrographic plates of the blue sky, the moon, and two stars. These Dumont plate data are inconsistent with 1958 Dobson spectrophotometer ozone measurements, inconsistent with present-day Antarctic observations, and inconsistent with meteorological and theoretical information. There is no credible evidence for an ozone hole in 1958.

  14. Karlson ozone sterilizer. Final report

    SciTech Connect

    Karlson, E.

    1984-05-07

    The authors have a functional sterilization system employing ozone as a sterilization agent. This final report covers the work that led to the first medical sterilizer using ozone as the sterilizing agent. The specifications and the final design were set by hospital operating room personnel and public safety standards. Work on kill tests using bacteria, viruses and fungi determined the necessary time and concentration of ozone necessary for sterilization. These data were used in the Karlson Ozone Sterilizer to determine the length of the steps of the operating cycle and the concentration of ozone to be used. 27 references.

  15. Precision ozone vapor pressure measurements

    NASA Technical Reports Server (NTRS)

    Hanson, D.; Mauersberger, K.

    1985-01-01

    The vapor pressure above liquid ozone has been measured with a high accuracy over a temperature range of 85 to 95 K. At the boiling point of liquid argon (87.3 K) an ozone vapor pressure of 0.0403 Torr was obtained with an accuracy of + or - 0.7 percent. A least square fit of the data provided the Clausius-Clapeyron equation for liquid ozone; a latent heat of 82.7 cal/g was calculated. High-precision vapor pressure data are expected to aid research in atmospheric ozone measurements and in many laboratory ozone studies such as measurements of cross sections and reaction rates.

  16. Validation of OMI total ozone retrievals from the SAO ozone profile algorithm and three operational algorithms with Brewer measurements

    NASA Astrophysics Data System (ADS)

    Bak, J.; Liu, X.; Kim, J. H.; Chance, K.; Haffner, D. P.

    2015-01-01

    The accuracy of total ozone computed from the Smithsonian Astrophysical Observatory (SAO) optimal estimation (OE) ozone profile algorithm (SOE) applied to the Ozone Monitoring Instrument (OMI) is assessed through comparisons with ground-based Brewer spectrometer measurements from 2005 to 2008. We also compare the three OMI operational ozone products, derived from the NASA Total Ozone Mapping Spectrometer (TOMS) algorithm, the KNMI (Royal Netherlands Meteorological Institute) differential optical absorption spectroscopy (DOAS) algorithm, and KNMI's Optimal Estimation (KOE) algorithm. The best agreement is observed between SAO and Brewer, with a mean difference of within 1% at most individual stations. The KNMI OE algorithm systematically overestimates Brewer total ozone by 2% at low and mid-latitudes and 5% at high latitudes while the TOMS and DOAS algorithms underestimate it by ~1.65% on average. Standard deviations of ~1.8% are calculated for both SOE and TOMS, but DOAS and KOE have higher values of 2.2% and 2.6%, respectively. The stability of the SOE algorithm is found to have insignificant dependence on viewing geometry, cloud parameters, or total ozone column. In comparison, the KOE-Brewer differences are significantly correlated with solar and viewing zenith angles and show significant deviations depending on cloud parameters and total ozone amount. The TOMS algorithm exhibits similar stability to SOE with respect to viewing geometry and total column ozone, but has stronger cloud parameter dependence. The dependence of DOAS on observational geometry and geophysical conditions is marginal compared to KOE, but is distinct compared to the SOE and TOMS algorithms. Comparisons of all four OMI products with Brewer show no apparent long-term drift, but seasonal features are evident, especially for KOE and TOMS. The substantial differences in the KOE vs. SOE algorithm performance cannot be sufficiently explained by the use of soft calibration (in SOE) and the use of

  17. Errors in ozone risk assessment using standard conditions for converting ozone concentrations obtained by passive samplers in mountain regions.

    PubMed

    Gerosa, G; Finco, A; Marzuoli, R; Ferretti, M; Gottardini, E

    2012-05-01

    Passive samplers are often employed to measure ozone concentrations in remote areas such as mountain forests. The potential ozone risk for vegetation is then assessed by calculating the AOT40 exposure index (accumulated hourly ozone concentration exceedances above 40 ppb, i.e. AOT40 = Σ([O(3)] - 40)Δt for any hourly ozone concentration [O(3)] > 40 ppb). AOT40 is customary calculated on the basis of ozone concentrations expressed as a volumetric mixing ratio, while lab sheets normally report ozone concentrations from passive samplers in mass units per cubic metre. Concentrations are usually converted from mass units to ppb using a standard conversion factor taking SATP (Standard Ambient Temperature and Pressure) conditions into account. These conditions, however, can vary considerably with elevation. As a consequence, the blanket application of a standard conversion factor may lead to substantial errors in reporting and mapping ozone concentrations and therefore in assessing potential ozone risk in mountain regions. In this paper we carry out a sensitivity analysis of the effects of uncertainties in estimations of air temperature (T) and atmospheric pressure (P) on the concentration conversion factor, and present two examples from two monitoring and mapping exercises carried out in the Italian Alps. We derived P and T at each site from adiabatic lapse rates for temperature and pressure and analysed the magnitude of error in concentration estimations. Results show that the concentration conversion is much more sensitive to uncertainties in P gradient estimation than to air temperature errors. The concentration conversion factor (cf) deviates 5% from the standard transformation at an elevation of 500 m asl. As a consequence, the standard estimated AOT40 at this elevation is about 13% less than the actual value. AOT40 was found to be underestimated by an average between 25% and 34% at typical elevations of mountain forest stands in the Italian Alps when a correct

  18. Ozone and nitrogen dioxide above the northern Tien Shan

    NASA Technical Reports Server (NTRS)

    Arefev, Vladimir N.; Volkovitsky, Oleg A.; Kamenogradsky, Nikita E.; Semyonov, Vladimir K.; Sinyakov, Valery P.

    1994-01-01

    The results of systematic perennial measurements of the total ozone (since 1979) and nitrogen dioxide column (since 1983) in the atmosphere in the European-Asian continent center above the mountainmass of the Tien Shan are given. This region is distinguished by a great number of sunny days during a year. The observation station is at the Northern shore of Issyk Kul Lake (42.56 N 77.04 E 1650 m above the sea level). The measurement results are presented as the monthly averaged atmospheric total ozone and NO2 stratospheric column abundances (morning and evening). The peculiarities of seasonal variations of ozone and nitrogen dioxide atmospheric contents, their regular variances with a quasi-biennial cycles and trends have been noticed. Irregular variances of ozone and nitrogen dioxide atmospheric contents, i.e. their positive and negative anomalies in the monthly averaged contents relative to the perennial averaged monthly means, have been analyzed. The synchronous and opposite in phase anomalies in variations of ozone and nitrogen dioxide atmospheric contents were explained by the transport and zonal circulation in the stratosphere (Kamenogradsky et al., 1990).

  19. Sweet potato [Ipomoea batatas (L.) Lam.] cultivated as tuber or leafy vegetable supplier as affected by elevated tropospheric ozone.

    PubMed

    Keutgen, Norbert; Keutgen, Anna J; Janssens, Marc J J

    2008-08-13

    Sweet potato cultivars respond differently to elevated tropospheric ozone concentrations of ca. 130 mug m (-3), 8 h a day for 4 weeks, which affects their selection for cultivation. In the first cultivar presented here, an adequate leafy vegetable supplier, the ozone load resulted in a shift of biomass to maintain the canopy at the expense of tuber development. Starch content of leaves was reduced, indicating an impairment of quality, but carotenoid content remained stable. The second cultivar may be grown for tuber production. Although the ratio tuber/plant remained stable under ozone, tuber yield and its starch content were significantly reduced. The lower starch content indicated a worse quality for certain industrial processing, but it is desirable for chip production. Elevated tropospheric ozone concentrations also influenced free amino acids and macronutrient contents of tubers, but these modifications were of minor significance for tuber quality in the second cultivar.

  20. Surface Ozone and Atmospheric Transport over the Gulf of Maine during ICARTT

    NASA Astrophysics Data System (ADS)

    Hintsa, E.; Twickler, M.; Talbot, R.; Rawlins, T.

    2005-12-01

    As part of the 2004 ICARTT summer campaign, we deployed a buoy with ozone and wind instruments about 20 km ESE of Appledore Island from late June through early September. Data from Thompson Farm, Appledore, and the buoy showed that on average, surface ozone levels over the Gulf of Maine increased with distance from the New Hampshire coast. Diurnally averaged ozone was highest at the buoy site, both in daytime and at night. The diurnal cycle at sea peaked several hours later than at Thompson Farm (3-6 PM EST vs. 1-3 PM). Trajectory and dispersion calculations showed that elevated ozone episodes were generally correlated with air masses from the New York-Boston corridor. The diurnal cycle in ozone at coastal and offshore sites at Martha's Vineyard (about 150 km to the south) was much smaller than in the Gulf of Maine (higher nighttime lows and lower daytime highs), reflecting a higher incidence of marine air at these stations. In summer 2004, the sea-breeze/land-breeze strongly influenced local transport and ozone levels at Appledore and the buoy. For onshore winds, the diurnal cycle in ozone was much smaller than for offshore winds but still present. A weekly cycle in ozone at the Gulf of Maine sites was also observed, with lowest daily ozone maxima on weekends.

  1. TOMS Tropical Tropospheric Ozone Data Sets at the University of Maryland Website

    NASA Technical Reports Server (NTRS)

    Kochhar, A. K.; Thompson, A. M.; Hudson, R. D.; Frolov, A. D.; Witte, J. C.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Since 1997, shortly after the launch of the Earth-Probe TOMS (Total Ozone Mapping Spectrometer) satellite instrument, we have been processing data in near-real time to post maps of tropical tropospheric ozone at a website: metosrv2.umd.edu/-tropo. Daily, 3-day and 9-day averages of tropical tropospheric ozone column depth (TTO) are viewable from 10N to 10S. Data can be downloaded (running 9-day means) from 20N-30S. Pollution events are trackable along with dynamically-induced variations in tropospheric ozone column. TOMS smoke aerosol (toms.gsfc.nasa.gov) can be used to interpret biomass burning ozone, as for example, during the extreme ozone and smoke pollution period during the ENSO-related fires of August November 1997. During that time plumes of ozone and smoke were frequently decoupled and ozone from Indonesian fires and from Africa merged in one large feature by late October 1997. In addition to the Earth-Probe TOMS record, data as half-month averages and as daily 9-day means from the Nimbus 7 TOMS instrument are at the metosrv2.umd.edu/-tropo website. A guide to the website and examples of ozone time-series and maps will be shown.

  2. Validation of ozone measurements from the Atmospheric Chemistry Experiment (ACE)

    NASA Astrophysics Data System (ADS)

    Dupuy, E.; Walker, K. A.; Kar, J.; Boone, C. D.; McElroy, C. T.; Bernath, P. F.; Drummond, J. R.; Skelton, R.; McLeod, S. D.; Hughes, R. C.; Nowlan, C. R.; Dufour, D. G.; Zou, J.; Nichitiu, F.; Strong, K.; Baron, P.; Bevilacqua, R. M.; Blumenstock, T.; Bodeker, G. E.; Borsdorff, T.; Bourassa, A. E.; Bovensmann, H.; Boyd, I. S.; Bracher, A.; Brogniez, C.; Burrows, J. P.; Catoire, V.; Ceccherini, S.; Chabrillat, S.; Christensen, T.; Coffey, M. T.; Cortesi, U.; Davies, J.; de Clercq, C.; Degenstein, D. A.; de Mazière, M.; Demoulin, P.; Dodion, J.; Firanski, B.; Fischer, H.; Forbes, G.; Froidevaux, L.; Fussen, D.; Gerard, P.; Godin-Beekmann, S.; Goutail, F.; Granville, J.; Griffith, D.; Haley, C. S.; Hannigan, J. W.; Höpfner, M.; Jin, J. J.; Jones, A.; Jones, N. B.; Jucks, K.; Kagawa, A.; Kasai, Y.; Kerzenmacher, T. E.; Kleinböhl, A.; Klekociuk, A. R.; Kramer, I.; Küllmann, H.; Kuttippurath, J.; Kyrölä, E.; Lambert, J.-C.; Livesey, N. J.; Llewellyn, E. J.; Lloyd, N. D.; Mahieu, E.; Manney, G. L.; Marshall, B. T.; McConnell, J. C.; McCormick, M. P.; McDermid, I. S.; McHugh, M.; McLinden, C. A.; Mellqvist, J.; Mizutani, K.; Murayama, Y.; Murtagh, D. P.; Oelhaf, H.; Parrish, A.; Petelina, S. V.; Piccolo, C.; Pommereau, J.-P.; Randall, C. E.; Robert, C.; Roth, C.; Schneider, M.; Senten, C.; Steck, T.; Strandberg, A.; Strawbridge, K. B.; Sussmann, R.; Swart, D. P. J.; Tarasick, D. W.; Taylor, J. R.; Tétard, C.; Thomason, L. W.; Thompson, A. M.; Tully, M. B.; Urban, J.; Vanhellemont, F.; Vigouroux, C.; von Clarmann, T.; von der Gathen, P.; von Savigny, C.; Waters, J. W.; Witte, J. C.; Wolff, M.; Zawodny, J. M.

    2009-01-01

    This paper presents extensive {bias determination} analyses of ozone observations from the Atmospheric Chemistry Experiment (ACE) satellite instruments: the ACE Fourier Transform Spectrometer (ACE-FTS) and the Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation (ACE-MAESTRO) instrument. Here we compare the latest ozone data products from ACE-FTS and ACE-MAESTRO with coincident observations from nearly 20 satellite-borne, airborne, balloon-borne and ground-based instruments, by analysing volume mixing ratio profiles and partial column densities. The ACE-FTS version 2.2 Ozone Update product reports more ozone than most correlative measurements from the upper troposphere to the lower mesosphere. At altitude levels from 16 to 44 km, the average values of the mean relative differences are nearly all within +1 to +8%. At higher altitudes (45-60 km), the ACE-FTS ozone amounts are significantly larger than those of the comparison instruments, with mean relative differences of up to +40% (about +20% on average). For the ACE-MAESTRO version 1.2 ozone data product, mean relative differences are within ±10% (average values within ±6%) between 18 and 40 km for both the sunrise and sunset measurements. At higher altitudes ( 35-55 km), systematic biases of opposite sign are found between the ACE-MAESTRO sunrise and sunset observations. While ozone amounts derived from the ACE-MAESTRO sunrise occultation data are often smaller than the coincident observations (with mean relative differences down to -10%), the sunset occultation profiles for ACE-MAESTRO show results that are qualitatively similar to ACE-FTS, indicating a large positive bias (mean relative differences within +10 to +30%) in the 45-55 km altitude range. In contrast, there is no significant systematic difference in bias found for the ACE-FTS sunrise and sunset measurements.

  3. Spatial regression analysis on 32 years of total column ozone data

    NASA Astrophysics Data System (ADS)

    Knibbe, J. S.; van der A, R. J.; de Laat, A. T. J.

    2014-08-01

    Multiple-regression analyses have been performed on 32 years of total ozone column data that was spatially gridded with a 1 × 1.5° resolution. The total ozone data consist of the MSR (Multi Sensor Reanalysis; 1979-2008) and 2 years of assimilated SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) ozone data (2009-2010). The two-dimensionality in this data set allows us to perform the regressions locally and investigate spatial patterns of regression coefficients and their explanatory power. Seasonal dependencies of ozone on regressors are included in the analysis. A new physically oriented model is developed to parameterize stratospheric ozone. Ozone variations on nonseasonal timescales are parameterized by explanatory variables describing the solar cycle, stratospheric aerosols, the quasi-biennial oscillation (QBO), El Niño-Southern Oscillation (ENSO) and stratospheric alternative halogens which are parameterized by the effective equivalent stratospheric chlorine (EESC). For several explanatory variables, seasonally adjusted versions of these explanatory variables are constructed to account for the difference in their effect on ozone throughout the year. To account for seasonal variation in ozone, explanatory variables describing the polar vortex, geopotential height, potential vorticity and average day length are included. Results of this regression model are compared to that of a similar analysis based on a more commonly applied statistically oriented model. The physically oriented model provides spatial patterns in the regression results for each explanatory variable. The EESC has a significant depleting effect on ozone at mid- and high latitudes, the solar cycle affects ozone positively mostly in the Southern Hemisphere, stratospheric aerosols affect ozone negatively at high northern latitudes, the effect of QBO is positive and negative in the tropics and mid- to high latitudes, respectively, and ENSO affects ozone negatively

  4. Impact of EOS MLS ozone data on medium-extended range ensemble weather forecasts

    NASA Astrophysics Data System (ADS)

    Cheung, J. C. H.; Haigh, J. D.; Jackson, D. R.

    2014-08-01

    As the stratosphere is largely characterized by its ozone abundance, the quality of the ozone field is important for a realistic representation of the stratosphere in weather and climate models. While the stratosphere is directly affected by radiative heating from ozone photodissociation, ozone abundance might also impact the representation of the troposphere since the stratosphere and troposphere are dynamically linked. In this paper, we examine the potential benefits of using ozone data from the Earth Observing System (EOS) Microwave Limb Sounder (MLS) for medium-extended range tropospheric forecasts in a current numerical weather prediction system. The global component of the Met Office Global and Regional Ensemble Prediction System is used, which is run at a resolution of N216 L85 with 24 ensemble members. We compare two scenarios of 31 day forecasts covering the same period, one with the current operational ozone climatology and the other with a monthly mean zonally averaged ozone field computed from the MLS data set. In the extreme case of the Arctic "ozone hole" of March 2011, our results show a general reduction in stratospheric forecast errors in the tropics and Southern Hemisphere as a result of the improved representation of ozone. However, even in such a scenario, where the MLS ozone field is much superior to that of the control, we find that tropospheric forecast errors in the medium-extended range are dominated by the spread of ensemble members and no significant reduction in the root-mean-square forecast errors.

  5. Vertical ozone distributions observed using tethered ozonesondes in a coastal industrial city, Kaohsiung, in southern Taiwan.

    PubMed

    Lin, Ching-Ho; Lai, Chin-Hsing; Wu, Yee-Lin; Lai, Hsin-Chih; Lin, Po-Hsiung

    2007-04-01

    This work presents the vertical distributions of ozone and meteorological parameters observed with tethered ozonesondes and meteorological radiosondes in the lower atmosphere during an ozone episode on March 25-27, 2003, in Kaohsiung City in southern Taiwan. Kaohsiung is a coastal industrial city with inland mountain ranges to the east. Extremely complicated ozone structures were identified that spanned day and night during the experimental period. During afternoons, the lower atmosphere was divided into two stratified air layers with substantially different ozone concentrations. On the episode day (March 26), average ozone concentration in the near-ground layer was 85 ppb and the aloft layer was 140 ppb. A very high ozone peak of 199 ppb measured aloft likely resulted from an elevated large point source. Several no-ozone air layers, distributed throughout 400-750 m, were observed to transport on shore during the night. As well, elevated ozone layers peaking at 60-90 ppb and 90-160 ppb were detected below and above the no-ozone air layers, respectively. These complicated ozone structures were likely formed through titration of plumes from large point sources and the circulations of sea breezes or combined sea-breeze/mountain flows in the study area.

  6. 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

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

    PubMed

    Zhang, Yuzhong; Wang, Yuhang

    2016-09-01

    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.

  8. Light environment alters ozone uptake per net photosynthetic rate in black cherry trees.

    PubMed

    Fredericksen, T S; Kolb, T E; Skelly, J M; Steiner, K C; Joyce, B J; Savage, J E

    1996-05-01

    Foliar ozone uptake rates of different-sized black cherry (Prunus serotina Ehrh.) trees were compared within a deciduous forest and adjacent openings in north-central Pennsylvania during one growing season. Study trees included open-grown seedlings and saplings, forest understory seedlings and saplings, and sunlit and shaded portions of mature canopy tree crowns. Instantaneous ozone uptake rates were highest in high-light environments primarily because of higher stomatal conductances. Low ozone uptake rates of seedlings and saplings in the forest understory could be attributed partially to lower average ambient ozone concentrations compared to the canopy and open environments. Among the tree size and light combinations tested, ozone uptake rates were highest in open-grown seedlings and lowest in forest-grown seedlings. Despite lower ozone uptake rates of foliage in shaded environments, ozone uptake per net photosynthesis of foliage in shaded environments was significantly higher than that of foliage in sunlit environments because of weaker coupling between net photosynthesis and stomatal conductance in shaded environments. The potential for greater ozone injury in shaded environments as a result of greater ozone uptake per net photosynthesis is consistent with previous reports of greater ozone injury in shaded foliage than in sunlit foliage. PMID:14871717

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

    PubMed

    Zhang, Yuzhong; Wang, Yuhang

    2016-09-01

    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

  10. Light environment alters ozone uptake per net photosynthetic rate in black cherry trees.

    PubMed

    Fredericksen, T S; Kolb, T E; Skelly, J M; Steiner, K C; Joyce, B J; Savage, J E

    1996-05-01

    Foliar ozone uptake rates of different-sized black cherry (Prunus serotina Ehrh.) trees were compared within a deciduous forest and adjacent openings in north-central Pennsylvania during one growing season. Study trees included open-grown seedlings and saplings, forest understory seedlings and saplings, and sunlit and shaded portions of mature canopy tree crowns. Instantaneous ozone uptake rates were highest in high-light environments primarily because of higher stomatal conductances. Low ozone uptake rates of seedlings and saplings in the forest understory could be attributed partially to lower average ambient ozone concentrations compared to the canopy and open environments. Among the tree size and light combinations tested, ozone uptake rates were highest in open-grown seedlings and lowest in forest-grown seedlings. Despite lower ozone uptake rates of foliage in shaded environments, ozone uptake per net photosynthesis of foliage in shaded environments was significantly higher than that of foliage in sunlit environments because of weaker coupling between net photosynthesis and stomatal conductance in shaded environments. The potential for greater ozone injury in shaded environments as a result of greater ozone uptake per net photosynthesis is consistent with previous reports of greater ozone injury in shaded foliage than in sunlit foliage.

  11. Distribution of injury and microdosimetry of ozone in the ventilatory unit of the rat

    SciTech Connect

    Pinkerton, K.E.; Mercer, R.R.; Plopper, C.G.; Crapo, J.D. )

    1992-09-01

    The distribution of ozone-induced injury across ventilatory units of the lungs was determined and compared with the predicted distribution of ozone dose across the same units to evaluate dose-response relationships. Sprague-Dawley rats were exposed to either 0.98 ppm ozone 8 h/day for 90 days or to filtered air only. En bloc microdissection was used to identify and isolate in longitudinal profile the bronchiole-alveolar duct junction, first pair of alveolar duct generations, and intervening bifurcation ridge. The first alveolar outpocketing along the bronchiolar wall of each isolation was used to identify the center of a series of concentric arcs radiating outward at 100-microns intervals across each ventilatory unit. The intercept lengths of each arc with the tissue of alveolar septal tips (edges) and alveolar walls were measured and expressed as a function of distance into the ventilatory unit. Relative ozone dose across the ventilatory unit was estimated using the geometry of the tracheobronchial tree and the volume and surface area distribution within individual ventilatory units. This mathematical model of ozone dose demonstrated a high degree of correlation to this measured tissue injury response. The findings of this study demonstrate that microdosimetry and microtoxicology can be used to determine dose-response relationships within the ventilatory unit and to assess questions of tissue sensitivity in ozone-induced lung injury.

  12. The Ozone Show.

    ERIC Educational Resources Information Center

    Mathieu, Aaron

    2000-01-01

    Uses a talk show activity for a final assessment tool for students to debate about the ozone hole. Students are assessed on five areas: (1) cooperative learning; (2) the written component; (3) content; (4) self-evaluation; and (5) peer evaluation. (SAH)

  13. Ozone and Cavitation Combination

    NASA Astrophysics Data System (ADS)

    Carreon, Ernestina; Traversoni, Leonardo

    2009-09-01

    From laboratory measurements it is well known that the addition of ozone and cavitation enhances the properties of both, understanding for that the ones related to disinfection and carbon removal from waste water. This paper shows modeling of such phenomena that gives some light to the understanding of it and also provides the opportunity to improve the effectiveness of the current procedures.

  14. Dobson ozone spectrophotometer modification.

    NASA Technical Reports Server (NTRS)

    Komhyr, W. D.; Grass, R. D.

    1972-01-01

    Description of a modified version of the Dobson ozone spectrophotometer in which several outdated electronic design features have been replaced by circuitry embodying more modern design concepts. The resulting improvement in performance characteristics has been obtained without changing the principle of operation of the original instrument.

  15. Ozone Layer Educator's Guide.

    ERIC Educational Resources Information Center

    Environmental Protection Agency, Washington, DC.

    This guide has been developed through a collaborative effort involving the U.S. Environmental Protection Agency (EPA), the National Oceanic and Atmospheric Administration (NOAA), and the National Aeronautics and Space Administration (NASA). It is part of an ongoing commitment to ensure that the results of scientific research on ozone depletion are…

  16. Ozone decomposing filter

    DOEpatents

    Simandl, Ronald F.; Brown, John D.; Whinnery, Jr., LeRoy L.

    1999-01-01

    In an improved ozone decomposing air filter carbon fibers are held together with a carbonized binder in a perforated structure. The structure is made by combining rayon fibers with gelatin, forming the mixture in a mold, freeze-drying, and vacuum baking.

  17. Ozone, CFCs and aerosols.

    PubMed

    1989-07-01

    Chlorofluorocarbons (CFCs) are, from the chemist's point of view, unique compounds with very valuable properties. They are inert, cheap and stable. But they also have devastating effects on the environment, destroying the ozone layer and adding to global warming or the greenhouse effect.

  18. Ozone decomposing filter

    SciTech Connect

    Simandl, R.F.; Brown, J.D.; Whinnery, L.L. Jr.

    1999-11-02

    In an improved ozone decomposing air filter carbon fibers are held together with a carbonized binder in a perforated structure. The structure is made by combining rayon fibers with gelatin, forming the mixture in a mold, freeze-drying, and vacuum baking.

  19. Identifying sources of ozone to three rural locations in Nevada, USA, using ancillary gas pollutants, aerosol chemistry, and mercury.

    PubMed

    Miller, Matthieu B; Fine, Rebekka; Pierce, Ashley M; Gustin, Mae S

    2015-10-15

    Ozone (O3) is a secondary air pollutant of long standing and increasing concern for environmental and human health, and as such, the US Environmental Protection Agency will revise the National Ambient Air Quality Standard of 75 ppbv to ≤ 70 ppbv. Long term measurements at the Great Basin National Park (GBNP) indicate that O3 in remote areas of Nevada will exceed a revised standard. As part of the Nevada Rural Ozone Initiative, measurements of O3 and other air pollutants were made at 3 remote sites between February 2012 and March 2014, GBNP, Paradise Valley (PAVA), and Echo Peak (ECHO). Exceptionally high concentrations of each air pollutant were defined relative to each site as mixing ratios that exceeded the 90th percentile of all hourly data. Case studies were analyzed for all periods during which mean daily O3 exceeded the 90th percentile concurrently with a maximum 8-h average (MDA8) O3 that was "exceptionally high" for the site (65 ppbv at PAVA, 70 ppbv at ECHO and GBNP), and of potential regulatory significance. An MDA8 ≥ 65 ppbv occurred only five times at PAVA, whereas this occurred on 49 and 65 days at GBNP and ECHO, respectively. The overall correlation between O3 and other pollutants was poor, consistent with the large distance from significant primary emission sources. Mean CO at these locations exceeded concentrations reported for background sites in 2000. Trajectory residence time calculations and air pollutant concentrations indicate that exceedances at GBNP and ECHO were promoted by air masses originating from multiple sources, including wildfires, transport of pollution from southern California and the marine boundary layer, and transport of Asian pollution plumes. Results indicate that the State of Nevada will exceed a revised O3 standard due to sources that are beyond their control. PMID:25957787

  20. Identifying sources of ozone to three rural locations in Nevada, USA, using ancillary gas pollutants, aerosol chemistry, and mercury.

    PubMed

    Miller, Matthieu B; Fine, Rebekka; Pierce, Ashley M; Gustin, Mae S

    2015-10-15

    Ozone (O3) is a secondary air pollutant of long standing and increasing concern for environmental and human health, and as such, the US Environmental Protection Agency will revise the National Ambient Air Quality Standard of 75 ppbv to ≤ 70 ppbv. Long term measurements at the Great Basin National Park (GBNP) indicate that O3 in remote areas of Nevada will exceed a revised standard. As part of the Nevada Rural Ozone Initiative, measurements of O3 and other air pollutants were made at 3 remote sites between February 2012 and March 2014, GBNP, Paradise Valley (PAVA), and Echo Peak (ECHO). Exceptionally high concentrations of each air pollutant were defined relative to each site as mixing ratios that exceeded the 90th percentile of all hourly data. Case studies were analyzed for all periods during which mean daily O3 exceeded the 90th percentile concurrently with a maximum 8-h average (MDA8) O3 that was "exceptionally high" for the site (65 ppbv at PAVA, 70 ppbv at ECHO and GBNP), and of potential regulatory significance. An MDA8 ≥ 65 ppbv occurred only five times at PAVA, whereas this occurred on 49 and 65 days at GBNP and ECHO, respectively. The overall correlation between O3 and other pollutants was poor, consistent with the large distance from significant primary emission sources. Mean CO at these locations exceeded concentrations reported for background sites in 2000. Trajectory residence time calculations and air pollutant concentrations indicate that exceedances at GBNP and ECHO were promoted by air masses originating from multiple sources, including wildfires, transport of pollution from southern California and the marine boundary layer, and transport of Asian pollution plumes. Results indicate that the State of Nevada will exceed a revised O3 standard due to sources that are beyond their control.

  1. Impact of greenhouse gases on the Earth's ozone layer

    NASA Astrophysics Data System (ADS)

    Zadorozhny, Alexander

    A numerical 2-D zonally averaged interactive dynamical radiative-photochemical model of the ozonosphere including aerosol physics is used to examine the role of the greenhouse gases CO2 , CH4 , and N2 O in the future long-term changes of the Earth's ozone layer, in particular in its recovery after reduction of anthropogenic discharges of chlorine and bromine compounds into the atmosphere. The model allows calculating self-consistently diabatic circulation, temperature, gaseous composition of the troposphere and stratosphere at latitudes from the South to North Poles, as well as distribution of sulphate aerosol particles and polar stratospheric clouds (PSCs) of types I and II. The scenarios of expected changes of the anthropogenic pollutants for the period from 1980 through 2050 are taken from Climate Change 2001. The processes, which determine the influence of anthropogenic growth of atmospheric abundance of the greenhouse gases on the dynamics of recovery of the Earth's ozone layer, have been studied in details. Expected cooling of the stratosphere caused by increases of greenhouse gases, most importantly CO2 , essentially influences the ozone layer by two ways: through temperature dependencies of the gas phase reaction rates and through enhancement of polar ozone depletion via increased PSC formation. The model calculations show that a weakness in efficiencies of all gas phase catalytic cycles of the ozone destruction due to cooling of the stratosphere is a dominant mechanism of the impact of the greenhouse gases on the ozone layer in Antarctic as well as at the lower latitudes. This mechanism leads to a significant acceleration of the ozone layer recovery here because of the greenhouse gases growth. On the contrary, the mechanism of the impact of the greenhouse gases on the ozone through PSC modification begins to be more effective in Arctic in comparison with the gas phase mechanism in springs after about 2020, which leads to retard the expected recovery of the

  2. Changes in the vertical distribution of ozone over Canada from ozonesondes: 1980-2001

    NASA Astrophysics Data System (ADS)

    Tarasick, D. W.; Fioletov, V. E.; Wardle, D. I.; Kerr, J. B.; Davies, J.

    2005-01-01

    Measurements of the vertical profile of ozone concentration using balloon-borne ECC ozonesondes have been made weekly since 1980 at several sites in Canada (Edmonton, Goose Bay, Churchill, and Resolute), since 1987 at Alert, and since 1992 at Eureka. Previous analyses of ozone trends over Canada have shown strong negative trends in tropospheric ozone. We present here a new analysis of trends in the vertical distribution of ozone with data up to the end of 2001. In addition, more detailed attention is paid to some potential sources of bias: total ozone correction, background current correction, and time-of-launch (diurnal) variation. For the 1980-2001 period the overall linear trends are primarily negative, both in tropospheric and stratospheric ozone. However, when the data for 1991-2001 only are considered, the trends are positive, even in the lower stratosphere. When the time series are compared with previously reported trends (to 1993), it is evident that ozone has rebounded at all levels below about 63 hPa. These differences do not appear to be related to changes in tropopause height, as the average height of the tropopause (as measured over the ozonesonde stations) has not changed over either the 22-year or the 11-year period. Nevertheless, comparison with another dynamical indicator, the wintertime frequency of occurrence of laminae in the ozone profile, suggests that this rebound may be partly a result of small changes in the atmospheric circulation, rather than a recovery of the ozone layer from halocarbon-induced depletion. The long-term trends in average tropospheric ozone concentrations over Canada are similar to corresponding lower stratospheric trends, and tropospheric ozone levels show significant correlation with lower stratospheric ozone amounts.

  3. VUV and soft x-ray ionization of a plant volatile: Vanillin (C8H8O3).

    PubMed

    Betancourt, A Moreno; Coutinho, L H; Bernini, R B; de Moura, C E V; Rocha, A B; de Souza, G G B

    2016-03-21

    Plant volatiles are emitted by plants in response to several forms of stress, including interaction with energetic photons. In the present work, we discuss the interaction of extreme UV and soft X-ray photons with a plant volatile, vanillin. The single and double (multiple) ionization of the vanillin molecule have been studied for the first time using time-of-flight mass spectrometry and VUV and soft X-ray photons (synchrotron radiation, at 12.0 eV, 21.2 eV, 130 eV, 310 eV, 531 eV, and 550 eV). At 12.0 and 21.2 eV, only singly charged species are observed and the parent ion, C8H8O3 (+), is the dominant species. Energy differences for some selected fragments were calculated theoretically in this energy region. At 130 eV, direct double and triple ionization of the valence electrons may occur. The fragmentation increases and CHO(+) becomes one of the main cations in the mass spectrum. The molecular ion is still the dominant species, but other fragments, such as C6H5O(+), begin to present similar intensities. At 310 eV, C 1s electrons may be ionized and Auger processes give rise to dissociative doubly ionized cations. Ionization around the O 1s edge has been studied both at the 531 eV resonance and above the ionization edge. Resonant and normal Auger processes play a significant role in each case and a large fragmentation of the molecule is observed at both photon energies, with intense fragments such as CHO(+) and CH3 (+) being clearly observed. A near edge X-ray absorption fine structure spectrum of the vanillin molecule was obtained around the O 1s ionization threshold. In addition, the fragmentation of vanillin has also been studied using a fast beam of electrons (800 eV), for the sake of comparison. PMID:27004874

  4. VUV and soft x-ray ionization of a plant volatile: Vanillin (C8H8O3).

    PubMed

    Betancourt, A Moreno; Coutinho, L H; Bernini, R B; de Moura, C E V; Rocha, A B; de Souza, G G B

    2016-03-21

    Plant volatiles are emitted by plants in response to several forms of stress, including interaction with energetic photons. In the present work, we discuss the interaction of extreme UV and soft X-ray photons with a plant volatile, vanillin. The single and double (multiple) ionization of the vanillin molecule have been studied for the first time using time-of-flight mass spectrometry and VUV and soft X-ray photons (synchrotron radiation, at 12.0 eV, 21.2 eV, 130 eV, 310 eV, 531 eV, and 550 eV). At 12.0 and 21.2 eV, only singly charged species are observed and the parent ion, C8H8O3 (+), is the dominant species. Energy differences for some selected fragments were calculated theoretically in this energy region. At 130 eV, direct double and triple ionization of the valence electrons may occur. The fragmentation increases and CHO(+) becomes one of the main cations in the mass spectrum. The molecular ion is still the dominant species, but other fragments, such as C6H5O(+), begin to present similar intensities. At 310 eV, C 1s electrons may be ionized and Auger processes give rise to dissociative doubly ionized cations. Ionization around the O 1s edge has been studied both at the 531 eV resonance and above the ionization edge. Resonant and normal Auger processes play a significant role in each case and a large fragmentation of the molecule is observed at both photon energies, with intense fragments such as CHO(+) and CH3 (+) being clearly observed. A near edge X-ray absorption fine structure spectrum of the vanillin molecule was obtained around the O 1s ionization threshold. In addition, the fragmentation of vanillin has also been studied using a fast beam of electrons (800 eV), for the sake of comparison.

  5. VUV and soft x-ray ionization of a plant volatile: Vanillin (C8H8O3)

    NASA Astrophysics Data System (ADS)

    Betancourt, A. Moreno; Coutinho, L. H.; Bernini, R. B.; de Moura, C. E. V.; Rocha, A. B.; de Souza, G. G. B.

    2016-03-01

    Plant volatiles are emitted by plants in response to several forms of stress, including interaction with energetic photons. In the present work, we discuss the interaction of extreme UV and soft X-ray photons with a plant volatile, vanillin. The single and double (multiple) ionization of the vanillin molecule have been studied for the first time using time-of-flight mass spectrometry and VUV and soft X-ray photons (synchrotron radiation, at 12.0 eV, 21.2 eV, 130 eV, 310 eV, 531 eV, and 550 eV). At 12.0 and 21.2 eV, only singly charged species are observed and the parent ion, C8H8O3+, is the dominant species. Energy differences for some selected fragments were calculated theoretically in this energy region. At 130 eV, direct double and triple ionization of the valence electrons may occur. The fragmentation increases and CHO+ becomes one of the main cations in the mass spectrum. The molecular ion is still the dominant species, but other fragments, such as C6H5O+, begin to present similar intensities. At 310 eV, C 1s electrons may be ionized and Auger processes give rise to dissociative doubly ionized cations. Ionization around the O 1s edge has been studied both at the 531 eV resonance and above the ionization edge. Resonant and normal Auger processes play a significant role in each case and a large fragmentation of the molecule is observed at both photon energies, with intense fragments such as CHO+ and CH3+ being clearly observed. A near edge X-ray absorption fine structure spectrum of the vanillin molecule was obtained around the O 1s ionization threshold. In addition, the fragmentation of vanillin has also been studied using a fast beam of electrons (800 eV), for the sake of comparison.

  6. Electrochemical concentration cell ozone soundings at two sites during the Stratospheric Ozone Intercomparison Campaign

    NASA Astrophysics Data System (ADS)

    Barnes, Robert A.; Torres, Arnold L.

    1995-05-01

    The Stratospheric Ozone Intercomparison Campaign (STOIC) was designed to compare proposed instruments for the Network for the Detection of Stratospheric Change (NDSC) with established measurement techniques. Ground-based measurements were conducted at Table Mountain, California (34.4°N, 117.7°W), and rocket profiles were made at San Nicolas Island, California (33.3°N, 119.5°W). In an effort to estimate site-to-site differences during the intercomparison, daily soundings were made with balloon-borne electrochemical concentration cell (ECC) ozonesondes at the two sites. Comparisons have been made of the mean values for the soundings at each site. The soundings showed small temperature differences between the two sites with the nighttime Table Mountain measurements up to 2°K cooler than the daytime San Nicolas Island temperatures. Day/night temperature corrections based on the emissivity and absorptivity of the thermistors in the balloon instruments can account for these apparent temperature differences. Ozone partial pressure profiles from the ECCs have been used to estimate atmospheric ozone variability during STOIC. Above 20 km, the lowest altitude for the STOIC comparisons, the average data sets from both sites showed standard deviations that were at or below the estimated 5-6% profile-to-profile repeatability for the ozonesondes. This indicates that atmospheric ozone variability was only of the order of a few percent above 20 km during the 2 weeks of the STOIC campaign. Above 20 km the ozone partial pressures over the Table Mountain site averaged 2.0% lower than over San Nicolas Island.

  7. A New ENSO Index Derived from Satellite Measurements of Column Ozone

    NASA Technical Reports Server (NTRS)

    Ziemke, J. R.; Chandra, S.; Oman, L. D.; Bhartia, P. K.

    2010-01-01

    Column Ozone measured in tropical latitudes from Nimbus 7 total ozone mapping spectrometer (TOMS), Earth Probe TOMS, solar backscatter ultraviolet (SBUV), and Aura ozone monitoring instrument (OMI) are used to derive an El Nino-Southern Oscillation (ENSO) index. This index, which covers a time period from 1979 to the present, is defined as the Ozone ENSO Index (OEI) and is the first developed from atmospheric trace gas measurements. The OEI is constructed by first averaging monthly mean column ozone over two broad regions in the western and eastern Pacific and then taking their difference. This differencing yields a self-calibrating ENSO index which is independent of individual instrument calibration offsets and drifts in measurements over the long record. The combined Aura OMI and MLS ozone data confirm that zonal variability in total column ozone in the tropics caused by ENSO events lies almost entirely in the troposphere. As a result, the OEI can be derived directly from total column ozone instead of tropospheric column ozone. For clear-sky ozone measurements a +1K change in Nino 3.4 index corresponds to +2.9 Dobson Unit (DU) change in the OEI, while a +1 hPa change in SOI coincides with a -1.7DU change in the OEI. For ozone measurements under all cloud conditions these numbers are +2.4DU and -1.4 DU, respectively. As an ENSO index based upon ozone, it is potentially useful in evaluating climate models predicting long term changes in ozone and other trace gases.

  8. A new ENSO index derived from satellite measurements of column ozone

    NASA Astrophysics Data System (ADS)

    Ziemke, J. R.; Chandra, S.; Oman, L. D.; Bhartia, P. K.

    2010-04-01

    Column Ozone measured in tropical latitudes from Nimbus 7 total ozone mapping spectrometer (TOMS), Earth Probe TOMS, solar backscatter ultraviolet (SBUV), and Aura ozone monitoring instrument (OMI) are used to derive an El Nino-Southern Oscillation (ENSO) index. This index, which covers a time period from 1979 to the present, is defined as the "Ozone ENSO Index" (OEI) and is the first developed from atmospheric trace gas measurements. The OEI is constructed by first averaging monthly mean column ozone over two broad regions in the western and eastern Pacific and then taking their difference. This differencing yields a self-calibrating ENSO index which is independent of individual instrument calibration offsets and drifts in measurements over the long record. The combined Aura OMI and MLS ozone data confirm that zonal variability in total column ozone in the tropics caused by ENSO events lies almost entirely in the troposphere. As a result, the OEI can be derived directly from total column ozone instead of tropospheric column ozone. For clear-sky ozone measurements a +1 K change in Nino 3.4 index corresponds to +2.9 Dobson Unit (DU) change in the OEI, while a +1 hPa change in SOI coincides with a -1.7 DU change in the OEI. For ozone measurements under all cloud conditions these numbers are +2.4 DU and -1.4 DU, respectively. As an ENSO index based upon ozone, it is potentially useful in evaluating climate models predicting long term changes in ozone and other trace gases.

  9. 16 CFR 260.11 - Ozone-safe and ozone-friendly claims.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... friendly to, the ozone layer or the atmosphere. Example 1: A product is labeled “ozone-friendly.” The claim... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Ozone-safe and ozone-friendly claims. 260.11... THE USE OF ENVIRONMENTAL MARKETING CLAIMS § 260.11 Ozone-safe and ozone-friendly claims. It...

  10. 16 CFR 260.11 - Ozone-safe and ozone-friendly claims.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... friendly to, the ozone layer or the atmosphere. Example 1: A product is labeled “ozone-friendly.” The claim... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Ozone-safe and ozone-friendly claims. 260.11... THE USE OF ENVIRONMENTAL MARKETING CLAIMS § 260.11 Ozone-safe and ozone-friendly claims. It...

  11. Ozone variability over Antarctic continent

    NASA Astrophysics Data System (ADS)

    Concepcion Parrondo, Mā; Yela, Margarita; Gil, Manuel; Ochoa, Hector

    2010-05-01

    Ozonesoundings data from Antarctic Belgrano Station (78°S, 34°W) carried out since 1999 are used to analyze the inter-annual variability of ozone in the troposphere and lower stratosphere. Tropospheric ozone has been calculated integrating the ozone content from the ground up to the ozone tropopause for each ozonesounding using Betan et al. [1996], definition. The annual cycle of the tropospheric ozone values shows an increase from summer to winter months. In August, tropospheric ozone almost doubles the values in February. Dynamical and chemical factors responsible of this behaviour are presented. Ozone loss rate during September in the lower stratosphere for the eleven year record is presented. The highest inter-annual ozone variability in observed during November and December in the lower stratosphere (12-27 km). Minimum ozone values concentration in the 20-27 km layer are found in November 2008. Mean 2008 December 12-20 km partial column remained below 40 DU, lower by 35% than the 2000-2005 mean. We present the relationship between the potential vorticity, timing of the vortex breakup date, the strength of the vortex and ozone concentration at different levels in an attempt to find dynamical features responsible for the observed behavior.

  12. CFCS and the ozone layer.

    PubMed

    Hayman, G D

    1997-05-01

    Ozone is an important constituent of the atmosphere. Ozone forms a distinct layer in the lower stratosphere known as the ozone layer. The ozone layer acts as a fragile shield because it protects man and other life forms from exposure to harmful short-wavelength ultraviolet (UV) radiation. The agents, particularly chemical, which affect the amount of ozone present in the atmosphere have been a source of concern for more than 20 years. This has been reinforced by the dramatic decline of stratospheric ozone levels first measured in Antarctica and now apparent worldwide. The combination of routine measurements of ozone depletion, careful laboratory studies and mathematical modelling of ozone in the atmosphere, has demonstrated that the reactive fragments produced when chlorofluorocarbons (CFCs), halons and other halogenated compounds break down in the stratosphere are responsible for the ozone loss. As CFCs have widespread and sometimes apparently essential uses in modern society, there has been an intense effort to develop safe, effective replacements which have a negligible or much smaller impact on the environment. The Montreal Protocol, signed by over 140 nations, has been implemented to control and phase out the chemical compounds responsible for ozone loss.

  13. Sensitivity of the FVGCM to Changes in Ozone

    NASA Technical Reports Server (NTRS)

    Stolarski; Pawson, S.; Nielsen, J. Eric; Douglass, A.; Newman, P.

    2004-01-01

    We have carried out an experiment with the finite volume general circulation model (FVGCM). This experiment consisted of two different imposed changes in the climatological ozone fields assumed in the radiation code. for conditions with no significant ozone hole. This distribution was obtained from a 50-year simulation of the full stratospheric ozone chemistry, with a time-dependent chlorine loading, done with our off-line chemical transport model (CTM). Three years (1978-1980) of this simulation were averaged to form a monthly, zonal-mean ozone distribution that was used in the 20-year integration of the FVGCM for "unperturbed" conditions. The second 20-year GCM integration included a fully-developed ozone hole. This ozone distribution was from three years, 1998-2000, from the same CTM simulation. The goal of this work is to determine the coupled response of the chemistry and dynamics of the stratosphere. These experiments are the first step in understanding the coupled response. An important initial question concerns the significance of the signals: if 20-year integrations turn out to be too short, the runs will be extended.

  14. Precision ozone calibration system based on vapor pressures of ozone

    NASA Technical Reports Server (NTRS)

    Mauersberger, K.; Hanson, D.; Morton, J.

    1987-01-01

    A precision ozone calibration system for stratospheric research has been developed and evaluated. Vapor pressures above solid ozone are mixed with a carrier gas (N2) to produce stratospheric ozone mixing ratios at total pressures of 1 to cover 20 torr. The uncertainty in the ozone mixing ratios is approximately + or - 1.5 percent, the stability of ozone is + or - 0.3 percent. Experiments to be calibrated may sample the gas mixture over a wide range of flow rates; the maximum throughput of gas with corrections of less than 1 percent to ozone is about 200 torr 1/min. A mass spectrometer system continuously monitors the purity and stability of the N2-O3 gas mixture.

  15. Moderate drought did not affect the effectiveness of ethylenediurea (EDU) in protecting Populus cathayana from ambient ozone.

    PubMed

    Xin, Yue; Yuan, Xiangyang; Shang, Bo; Manning, William J; Yang, Aizhen; Wang, Younian; Feng, Zhaozhong

    2016-11-01

    A field study was conducted to evaluate the effects of ambient ozone (O3) on an O3-sensitive poplar (Populus cathayana) by using ethylenediurea (EDU) as a chemical protectant under two soil water treatments (well-watered (WW) and moderate drought (MD, 50-60% of WW in volumetric soil water content). EDU was applied as foliar spray at 0, 300, 450, and 600ppm. Photosynthetic parameters, pigment contents, leaf nitrogen, antioxidant capacity, growth, and biomass were measured. The 8h (9:00-17:00) average ambient O3 concentration was 71.7ppb, and AOT40 was 29.2ppmh during the experimental period (9 June to 21 September), which was high enough to cause plant injury. MD had significantly negative effects on P. cathayana, as indicated by reduced photosynthesis, growth, and biomass, and higher MDA contents. On the other hand, EDU significantly increased photosynthesis rate, chlorophyll a fluorescence, Vcmax and Jmax, photosynthetic pigments, total antioxidant capacity, tree growth and biomass accumulation, and reduced lipid peroxidation, but there was no significant interaction between EDU and drought for most parameters, indicating that EDU can efficiently protect Populus cathayana against ambient O3 and the protection was not affected by soil water contents when soil water reached moderate drought level. Among all doses, EDU at 450ppm provided maximum protection. Comparison of EDU-treated and non-treated P. cathayana could be used as a biomarker system in risk assessment of the effects of ambient O3 on forest health. PMID:27424114

  16. Ozone, nitric acid, and ammonia air pollution is unhealthy for people and ecosystems in southern Sierra Nevada, California.

    PubMed

    Cisneros, Ricardo; Bytnerowicz, Andrzej; Schweizer, Donald; Zhong, Sharon; Traina, Samuel; Bennett, Deborah H

    2010-10-01

    Two-week average concentrations of ozone (O3), nitric acid vapor (HNO3) and ammonia (NH3) were measured with passive samplers during the 2002 summer season across the central Sierra Nevada Mountains, California, along the San Joaquin River drainage. Elevated concentrations of the pollutants were determined with seasonal means for individual sites ranging between 62 and 88 ppb for O3, 1.0-3.8 microg m(-3) for HNO3, and 2.6-5.2 microg m(-3) for NH3. Calculated O3 exposure indices were very high, reaching SUM00-191 ppm h, SUM60-151 ppm h, and W126-124 ppm h. Calculated nitrogen (N) dry deposition ranged from 1.4 to 15 kg N ha(-1) for maximum values, and 0.4-8 kg N ha(-1) for minimum values; potentially exceeding Critical Loads (CL) for nutritional N. The U.S., California, and European 8 h O3 human health standards were exceeded during 104, 108, and 114 days respectively, indicating high risk to humans from ambient O3. PMID:20708832

  17. Probabilistic aspects of meteorological and ozone regional ensemble forecasts

    SciTech Connect

    Monache, L D; Hacker, J; Zhou, Y; Deng, X; Stull, R

    2006-03-20

    This study investigates whether probabilistic ozone forecasts from an ensemble can be made with skill; i.e., high verification resolution and reliability. Twenty-eight ozone forecasts were generated over the Lower Fraser Valley, British Columbia, Canada, for the 5-day period 11-15 August 2004, and compared with 1-hour averaged measurements of ozone concentrations at five stations. The forecasts were obtained by driving the CMAQ model with four meteorological forecasts and seven emission scenarios: a control run, {+-} 50% NO{sub x}, {+-} 50% VOC, and {+-} 50% NO{sub x} combined with VOC. Probabilistic forecast quality is verified using relative operating characteristic curves, Talagrand diagrams, and a new reliability index. Results show that both meteorology and emission perturbations are needed to have a skillful probabilistic forecast system--the meteorology perturbation is important to capture the ozone temporal and spatial distribution, and the emission perturbation is needed to span the range of ozone-concentration magnitudes. Emission perturbations are more important than meteorology perturbations for capturing the likelihood of high ozone concentrations. Perturbations involving NO{sub x} resulted in a more skillful probabilistic forecast for the episode analyzed, and therefore the 50% perturbation values appears to span much of the emission uncertainty for this case. All of the ensembles analyzed show a high ozone concentration bias in the Talagrand diagrams, even when the biases from the unperturbed emissions forecasts are removed from all ensemble members. This result indicates nonlinearity in the ensemble, which arises from both ozone chemistry and its interaction with input from particular meteorological models.

  18. Balloonborne ozone and aerosol measurements in the antarctic ozone hole

    SciTech Connect

    Hofmann, D.J.; Harder, J.W.; Rolf, S.R.; Rosen, J.M. )

    1987-01-01

    The National Ozone Expedition (NOZE) was mounted in 1986 using winter fly-in flights to McMurdo Station in August, which is approximately the time the ozone reduction begins. The University of Wyoming Atmospheric Physics group participated in this expedition through balloonborne measurements of the vertical distribution of ozone and aerosol particles. Between 24 August and 6 November, 33 ozone soundings, 6 aerosol sounding, and 3 condensation nuclei soundings were conducted using polyethylene balloons which were able to penetrate the cold (< {minus}80C) antarctic stratosphere. The authors summarize these results here.

  19. Ozone and ozone byproducts in the cabins of commercial aircraft.

    PubMed

    Weisel, Clifford; Weschler, Charles J; Mohan, Kris; Vallarino, Jose; Spengler, John D

    2013-05-01

    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 >75 ppb. 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

  20. Fundamental differences between Arctic and Antarctic ozone depletion.

    PubMed

    Solomon, Susan; Haskins, Jessica; Ivy, Diane J; Min, Flora

    2014-04-29

    Antarctic ozone depletion is associated with enhanced chlorine from anthropogenic chlorofluorocarbons and heterogeneous chemistry under cold conditions. The deep Antarctic "hole" contrasts with the generally weaker depletions observed in the warmer Arctic. An unusually cold Arctic stratospheric season occurred in 2011, raising the question of how the Arctic ozone chemistry in that year compares with others. We show that the averaged depletions near 20 km across the cold part of each pole are deeper in Antarctica than in the Arctic for all years, although 2011 Arctic values do rival those seen in less-depleted years in Antarctica. We focus not only on averages but also on extremes, to address whether or not Arctic ozone depletion can be as extreme as that observed in the Antarctic. This information provides unique insights into the contrasts between Arctic and Antarctic ozone chemistry. We show that extreme Antarctic ozone minima fall to or below 0.1 parts per million by volume (ppmv) at 18 and 20 km (about 70 and 50 mbar) whereas the lowest Arctic ozone values are about 0.5 ppmv at these altitudes. At a higher altitude of 24 km (30-mbar level), no Arctic data below about 2 ppmv have been observed, including in 2011, in contrast to values more than an order of magnitude lower in Antarctica. The data show that the lowest ozone values are associated with temperatures below -80 °C to -85 °C depending upon altitude, and are closely associated with reduced gaseous nitric acid concentrations due to uptake and/or sedimentation in polar stratospheric cloud particles. PMID:24733920

  1. Fundamental differences between Arctic and Antarctic ozone depletion

    PubMed Central

    Solomon, Susan; Haskins, Jessica; Ivy, Diane J.; Min, Flora

    2014-01-01

    Antarctic ozone depletion is associated with enhanced chlorine from anthropogenic chlorofluorocarbons and heterogeneous chemistry under cold conditions. The deep Antarctic “hole” contrasts with the generally weaker depletions observed in the warmer Arctic. An unusually cold Arctic stratospheric season occurred in 2011, raising the question of how the Arctic ozone chemistry in that year compares with others. We show that the averaged depletions near 20 km across the cold part of each pole are deeper in Antarctica than in the Arctic for all years, although 2011 Arctic values do rival those seen in less-depleted years in Antarctica. We focus not only on averages but also on extremes, to address whether or not Arctic ozone depletion can be as extreme as that observed in the Antarctic. This information provides unique insights into the contrasts between Arctic and Antarctic ozone chemistry. We show that extreme Antarctic ozone minima fall to or below 0.1 parts per million by volume (ppmv) at 18 and 20 km (about 70 and 50 mbar) whereas the lowest Arctic ozone values are about 0.5 ppmv at these altitudes. At a higher altitude of 24 km (30-mbar level), no Arctic data below about 2 ppmv have been observed, including in 2011, in contrast to values more than an order of magnitude lower in Antarctica. The data show that the lowest ozone values are associated with temperatures below −80 °C to −85 °C depending upon altitude, and are closely associated with reduced gaseous nitric acid concentrations due to uptake and/or sedimentation in polar stratospheric cloud particles. PMID:24733920

  2. Fundamental differences between Arctic and Antarctic ozone depletion.

    PubMed

    Solomon, Susan; Haskins, Jessica; Ivy, Diane J; Min, Flora

    2014-04-29

    Antarctic ozone depletion is associated with enhanced chlorine from anthropogenic chlorofluorocarbons and heterogeneous chemistry under cold conditions. The deep Antarctic "hole" contrasts with the generally weaker depletions observed in the warmer Arctic. An unusually cold Arctic stratospheric season occurred in 2011, raising the question of how the Arctic ozone chemistry in that year compares with others. We show that the averaged depletions near 20 km across the cold part of each pole are deeper in Antarctica than in the Arctic for all years, although 2011 Arctic values do rival those seen in less-depleted years in Antarctica. We focus not only on averages but also on extremes, to address whether or not Arctic ozone depletion can be as extreme as that observed in the Antarctic. This information provides unique insights into the contrasts between Arctic and Antarctic ozone chemistry. We show that extreme Antarctic ozone minima fall to or below 0.1 parts per million by volume (ppmv) at 18 and 20 km (about 70 and 50 mbar) whereas the lowest Arctic ozone values are about 0.5 ppmv at these altitudes. At a higher altitude of 24 km (30-mbar level), no Arctic data below about 2 ppmv have been observed, including in 2011, in contrast to values more than an order of magnitude lower in Antarctica. The data show that the lowest ozone values are associated with temperatures below -80 °C to -85 °C depending upon altitude, and are closely associated with reduced gaseous nitric acid concentrations due to uptake and/or sedimentation in polar stratospheric cloud particles.

  3. Comparison of modelled and measured ozone concentrations and meteorology for a site in south-west Sweden: implications for ozone uptake calculations.

    PubMed

    Klingberg, Jenny; Danielsson, Helena; Simpson, David; Pleijel, Håkan

    2008-09-01

    Measurements of ground-level ozone concentrations and meteorology (temperature, vapour pressure deficit (VPD), solar radiation) at the monitoring site Ostad (south-west Sweden) were compared to data from the corresponding grid in the EMEP photo-oxidant model for 1997, 1999 and 2000. The influence of synoptic weather on the agreement between model and measurements was studied. Implications of differences between modelled and observed inputs for ozone flux calculations for wheat and potato were investigated. The EMEP model output of ozone, temperature and VPD correlated well with measurements during daytime. Deviations were larger during the night, especially in calm conditions, attributed to local climatological conditions at the monitoring site deviating from average conditions of the grid. These differences did not lead to significant differences in calculated ozone uptake, which was reproduced remarkably well. The uptake calculations were sensitive to errors in the ozone and temperature input data, especially when including a flux threshold.

  4. Factors influencing the ground level distribution of ozone in Europe.

    PubMed

    Derwent, R G; Kay, P J

    1988-01-01

    Ozone is a widely distributed pollutant in the atmospheric boundary layer over north west Europe. Three main sources have been identified: the stratosphere, the free troposphere and boundary layer photochemical production. The pattern of ground level ozone concentrations resulting from these three sources cannot be accurately specified. Ozone shows significant variations in space and time but because of the high cost of continuous monitoring equipment, spatial variations on a national and international basis have not been studied in detail. Variations in ozone concentrations at individual monitoring sites have been given a great deal of attention and experience gained from United Kingdom monitoring sites is described in some detail. The averaging time statistical model of Larsen is employed to relate the exposure levels measured over different averaging periods. Diurnal variations have a major influence on exposure levels at sites nominally exposed to the same regional ozone distribution. The physical and chemical mechanisms which give rise to diurnal variations are detailed so that sites can be screened for different diurnal behaviour characteristics.

  5. Intercomparison of stratospheric ozone profiles for the assessment of the upgraded GROMOS radiometer at Bern

    NASA Astrophysics Data System (ADS)

    Studer, S.; Hocke, K.; Pastel, M.; Godin-Beekmann, S.; Kämpfer, N.

    2013-07-01

    Since November 1994, the GROund-based Millimeter-wave Ozone Spectrometer (GROMOS) measures stratospheric and lower mesospheric ozone in Bern, Switzerland (47.95° N, 7.44° E). GROMOS is part of the Network for the Detection of Atmospheric Composition Change (NDACC). In July 2009, a Fast-Fourier-Transform spectrometer (FFTS) has been added as backend to GROMOS. The new FFTS and the original filter bench (FB) measured parallel for over two years. In October 2011, the FB has been turned off and the FFTS is now used to continue the ozone time series. For a consolidated ozone time series in the frame of NDACC, the quality of the stratospheric ozone profiles obtained with the FFTS has to be assessed. The FFTS results from July 2009 to December 2011 are compared to ozone profiles retrieved by the FB. FFTS and FB of the GROMOS microwave radiometer agree within 5% above 20 hPa. A later harmonization of both time series will be realized by taking the FFTS as benchmark for the FB. Ozone profiles from the FFTS are also compared to coinciding lidar measurements from the Observatoire Haute Provence (OHP), France. For the time period studied a maximum mean difference (lidar - GROMOS FFTS) of +3.8% at 3.1 hPa and a minimum mean difference of +1.4% at 8 hPa is found. Further, intercomparisons with ozone profiles from other independent instruments are performed: satellite measurements include MIPAS onboard ENVISAT, SABER onboard TIMED, MLS onboard EOS Aura and ACE-FTS onboard SCISAT-1. Additionally, ozonesondes launched from Payerne, Switzerland, are used in the lower stratosphere. Mean relative differences of GROMOS FFTS and these independent instruments are less than 10% between 50 and 0.1 hPa.

  6. Degradation of carbofuran by ozonation.

    PubMed

    Suneethi, S; Joseph, Kurian

    2009-04-01

    Degradation of commercial grade carbofuran (2, 3 dihydro-2, 2-dimethyl-7 benzo furanyl-N-methyl carbamate) in aqueous solution by ozone oxidation was investigated using bench scale experiments. The degradation rate was strongly influenced by the ozone dosage, pH, initial concentration of carbofuran and contact time of ozonation. Carbofuran solution of 200ppm concentration was degraded by 79% within 10 minutes consuming 87 mg of ozone at pH 4. The associated TOC reduction was observed to be 53%. Ammonium (20 mg/L) and nitrate (30 mg/L) ions were detected in the effluent as degradation products of ozonation. The results support the effectiveness of ozonation for degradation of organic pesticides such as carbofuran.

  7. Ozone Risk Assessment Utilities

    1999-08-10

    ORAMUS is a user-friendly, menu-driven software system that calculates and displays user-selected risk estimates for health effects attributable to short-term exposure to tropospheric ozone. Inputs to the risk assessment are estimates of exposure to ozone and exposure-response relationships to produce overall risk estimates in the form of probability distributions. Three fundamental models are included: headcount risk, benchmark risk, and hospital admissions. Exposure-response relationships are based on results of controlled human exposure studies. Exposure estimates aremore » based on the EPA''s probabilistic national ambient air quality standards (NAAQS) exposure model, pNEM/Osub3, which simulates air quality associated with attainment of alternative NAAQS. Using ORAMUS, risk results for 27 air quality scenarios, air quality in 9 urban areas, 33 health endpoints, and 4 chronic health endpoints can be calculated.« less

  8. Domestic versus international contributions on 2050 ozone air quality: How much is convertible by regional control?

    NASA Astrophysics Data System (ADS)

    Lei, Hang; Wuebbles, Donald J.; Liang, Xin-Zhong; Olsen, Seth

    2013-04-01

    A global climate chemistry model CAM-Chem is driven by the meteorology output from community climate system model version 3 (CCSM3) to investigate the relative contributions of changes in local anthropogenic emissions (LE) versus changes in remote anthropogenic emissions (RE) to global surface ozone air quality in 2050. On major ozone pollution regions (Europe, the United States, Asia), the effects are examined following three distinct pathways, A1FI, A1B and B1, from the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) to address the uncertainty in projections of future climate and emissions. We find that projected changes in anthropogenic emissions under the A1FI scenario lead to an increase of 5-14 ppb in summertime daily maximum 8-h (DM8H) ozone concentration over U.S. by 2050, of which 48% is contributed by LE changes and 52% is contributed by RE changes. For Europe, the change in local emissions contributes 62% of the surface ozone increase in 2050 summer, while 38% of the increase is attributed to remote emission change. For Asia, changes in LE dominate the 2050 surface ozone increase with a magnitude of 10-30 ppb on summertime DM8H ozone concentration. However, under the A1B and B1 scenarios, contributions from LE changes are much larger than that from RE changes over all three regions except Asia under the B1 scenario, in which the RE changes contribute 31% of total change. The results indicate that for the United States and Europe, pollution control is a local issue under global low emission situations, while it becomes an international issue when fossil fuel use is rapidly increasing. Due to the weak Euro-Asia transport, local emission increase seems to be the main force for Asia's ozone air quality change under all cases except the low emission scenario B1. Therefore, the strategies for regional air quality control need to be based on global emission situation.

  9. Ozonated olive oils and the troubles.

    PubMed

    Uysal, Bulent

    2014-01-01

    One of the commonly used methods for ozone therapy is ozonated oils. Most prominent type of used oils is extra virgin olive oil. But still, each type of unsaturated oils may be used for ozonation. There are a lot of wrong knowledge on the internet about ozonated oils and its use as well. Just like other ozone therapy studies, also the studies about ozone oils are inadequate to avoid incorrect knowledge. Current data about ozone oil and its benefits are produced by supplier who oversees financial interests and make misinformation. Despite the rapidly increasing ozone oil sales through the internet, its quality and efficacy is still controversial. Dozens of companies and web sites may be easily found to buy ozonated oil. But, very few of these products are reliable, and contain sufficiently ozonated oil. This article aimed to introduce the troubles about ozonated oils and so to inform ozonated oil users. PMID:26401346

  10. Ozone, Air Quality, and Asthma (For Parents)

    MedlinePlus

    ... found in both the Earth's upper and lower atmospheres. The protective ozone in the upper atmosphere is very different from the harmful ozone in the lower atmosphere. Ozone that exists naturally 10 to 30 miles ( ...

  11. A Novel Gene, OZONE-RESPONSIVE APOPLASTIC PROTEIN1, Enhances Cell Death in Ozone Stress in Rice.

    PubMed

    Ueda, Yoshiaki; Siddique, Shahid; Frei, Michael

    2015-09-01

    A novel protein, OZONE-RESPONSIVE APOPLASTIC PROTEIN1 (OsORAP1), was characterized, which was previously suggested as a candidate gene underlying OzT9, a quantitative trait locus for ozone stress tolerance in rice (Oryza sativa). The sequence of OsORAP1 was similar to that of ASCORBATE OXIDASE (AO) proteins. It was localized in the apoplast, as shown by transient expression of an OsORAP1/green fluorescent protein fusion construct in Nicotiana benthamiana leaf epidermal and mesophyll cells, but did not possess AO activity, as shown by heterologous expression of OsORAP1 in Arabidopsis (Arabidopsis thaliana) mutants with reduced background AO activity. A knockout rice line of OsORAP1 showed enhanced tolerance to ozone stress (120 nL L(-1) average daytime concentration, 20 d), as demonstrated by less formation of leaf visible symptoms (i.e. cell death), less lipid peroxidation, and lower NADPH oxidase activity, indicating reduced active production of reactive oxygen species. In contrast, the effect of ozone on chlorophyll content was not significantly different among the lines. These observations suggested that OsORAP1 specifically induced cell death in ozone stress. Significantly enhanced expression of jasmonic acid-responsive genes in the knockout line implied the involvement of the jasmonic acid pathway in symptom mitigation. Sequence analysis revealed extensive polymorphisms in the promoter region of OsORAP1 between the ozone-susceptible cv Nipponbare and the ozone-tolerant cv Kasalath, the OzT9 donor variety, which could be responsible for the differential regulation of OsORAP1 reported earlier. These pieces of evidence suggested that OsORAP1 enhanced cell death in ozone stress, and its expression levels could explain the effect of a previously reported quantitative trait locus.

  12. A Novel Gene, OZONE-RESPONSIVE APOPLASTIC PROTEIN1, Enhances Cell Death in Ozone Stress in Rice1

    PubMed Central

    Ueda, Yoshiaki; Siddique, Shahid; Frei, Michael

    2015-01-01

    A novel protein, OZONE-RESPONSIVE APOPLASTIC PROTEIN1 (OsORAP1), was characterized, which was previously suggested as a candidate gene underlying OzT9, a quantitative trait locus for ozone stress tolerance in rice (Oryza sativa). The sequence of OsORAP1 was similar to that of ASCORBATE OXIDASE (AO) proteins. It was localized in the apoplast, as shown by transient expression of an OsORAP1/green fluorescent protein fusion construct in Nicotiana benthamiana leaf epidermal and mesophyll cells, but did not possess AO activity, as shown by heterologous expression of OsORAP1 in Arabidopsis (Arabidopsis thaliana) mutants with reduced background AO activity. A knockout rice line of OsORAP1 showed enhanced tolerance to ozone stress (120 nL L−1 average daytime concentration, 20 d), as demonstrated by less formation of leaf visible symptoms (i.e. cell death), less lipid peroxidation, and lower NADPH oxidase activity, indicating reduced active production of reactive oxygen species. In contrast, the effect of ozone on chlorophyll content was not significantly different among the lines. These observations suggested that OsORAP1 specifically induced cell death in ozone stress. Significantly enhanced expression of jasmonic acid-responsive genes in the knockout line implied the involvement of the jasmonic acid pathway in symptom mitigation. Sequence analysis revealed extensive polymorphisms in the promoter region of OsORAP1 between the ozone-susceptible cv Nipponbare and the ozone-tolerant cv Kasalath, the OzT9 donor variety, which could be responsible for the differential regulation of OsORAP1 reported earlier. These pieces of evidence suggested that OsORAP1 enhanced cell death in ozone stress, and its expression levels could explain the effect of a previously reported quantitative trait locus. PMID:26220952

  13. Ozone Air Quality Impacts of Shale Gas Development in South Texas Urban Areas

    NASA Astrophysics Data System (ADS)

    Chang, C.; Liao, K.

    2013-12-01

    Recent technological advances, mainly horizontal drilling and hydraulic fracturing, and continued drilling in shale, have increased domestic production of oil and gas in the United State (U.S.). However, shale gas developments could also affect the environment and human health, particularly in areas where oil and gas developments are new activities. This study is focused on the impacts of shale gas developing activities on summertime ozone air quality in South Texas urban areas since many of them are already ozone nonattainment areas. We use an integrated approach to investigate the ozone air quality impact of the shale gas development in South Texas urban areas. They are: (1) satellite measurement of precursors, (2) observations of ground-level ozone concentrations, and (3) air mass trajectory modeling. Nitrogen dioxide (NO2) is an important precursor to ozone formation, and summertime average tropospheric nitrogen dioxide (NO2) column densities measured by the National Aeronautics and Space Administration's Ozone Monitoring Instrument increased in the South Texas shale area (i.e., the Eagle Ford Shale area) in 2011 and 2012 as compared to 2008-2010. The U.S. Environmental Protection Agency's ground-level observations showed summertime average and peak ozone (i.e., the 4th highest daily maximum 8-hour average ozone) concentrations slightly increased from 2010 to 2012 in Austin and San Antonio. However, the frequencies of peak ozone concentrations above the 75ppb ozone standard have been significantly increasing since 2011 in Austin and San Antonio. It is expected to increase the possibilities of violating the ozone National Ambient Air Quality Standard (NAAQS) for South Texas urban areas in the future. The results of trajectory modeling showed air masses transported from the southeastern Texas could reach Austin and San Antonio and confirmed that emissions from the Eagle Ford Shale area could affect ozone air quality in South Texas urban areas in 2011 and 2012

  14. Protecting the ozone layer.

    PubMed

    Munasinghe, M; King, K

    1992-06-01

    Stratospheric ozone layer depletion has been recognized as a problem by the Vienna Convention for the Protection of the Ozone Layer and the 1987 Montreal Protocol (MP). The ozone layer shields the earth from harmful ultraviolet radiation (UV-B), which is more pronounced at the poles and around the equator. Industrialized countries have contributed significantly to the problem by releasing chlorofluorocarbons (CFCs) and halons into the atmosphere. The effect of these chemicals, which were known for their inertness, nonflammability, and nontoxicity, was discovered in 1874. Action to deal with the effects of CFCs and halons was initiated in 1985 in a 49-nation UN meeting. 21 nations signed a protocol limiting ozone depleting substances (ODS): CFCs and halons. Schedules were set based on each country's use in 1986; the target phaseout was set for the year 2000. The MP restricts trade in ODSs and weights the impact of substances to reflect the extent of damage; i.e., halons are 10 times more damaging than CFCs. ODS requirements for developing countries were eased to accommodate scarce resources and the small fraction of ODS emissions. An Interim Multilateral Fund under the Montreal Protocol (IMFMP) was established to provide loans to finance the costs to developing countries in meeting global environmental requirements. The IMFMP is administered by the World Bank, the UN Environmental Program, and the UN Development Program. Financing is available to eligible countries who use .3 kg of ODS/person/year. Rapid phaseout in developed countries has occurred due to strong support from industry and a lower than expected cost. Although there are clear advantages to rapid phaseout, there were no incentives included in the MP for rapid phaseout. Some of the difficulties occur because the schedules set minimum targets at the lowest possible cost. Also, costs cannot be minimized by a country-specific and ODS-specific process. The ways to improve implementation in scheduling and

  15. Ozone attainment: A different perspective

    SciTech Connect

    Beck, W.B. )

    1988-01-01

    Recent attention on the ozone non-attainment issue has been focused on Washington. Both Congress and the EPA have made efforts at addressing the post-1987 crisis in the many non-attainment areas. In contrast to the political activity, this paper presents some interesting technical perspectives on ozone attainment for many areas of the U.S.. Issues such as transport, climate and natural ozone sources are discussed in the context of exceedance frequency for several geographical areas of the country.

  16. Multimodel projections of stratospheric ozone in the 21st century

    NASA Astrophysics Data System (ADS)

    Eyring, V.; Waugh, D. W.; Bodeker, G. E.; Cordero, E.; Akiyoshi, H.; Austin, J.; Beagley, S. R.; Boville, B. A.; Braesicke, P.; Brühl, C.; Butchart, N.; Chipperfield, M. P.; Dameris, M.; Deckert, R.; Deushi, M.; Frith, S. M.; Garcia, R. R.; Gettelman, A.; Giorgetta, M. A.; Kinnison, D. E.; Mancini, E.; Manzini, E.; Marsh, D. R.; Matthes, S.; Nagashima, T.; Newman, P. A.; Nielsen, J. E.; Pawson, S.; Pitari, G.; Plummer, D. A.; Rozanov, E.; Schraner, M.; Scinocca, J. F.; Semeniuk, K.; Shepherd, T. G.; Shibata, K.; Steil, B.; Stolarski, R. S.; Tian, W.; Yoshiki, M.

    2007-08-01

    Simulations from eleven coupled chemistry-climate models (CCMs) employing nearly identical forcings have been used to project the evolution of stratospheric ozone throughout the 21st century. The model-to-model agreement in projected temperature trends is good, and all CCMs predict continued, global mean cooling of the stratosphere over the next 5 decades, increasing from around 0.25 K/decade at 50 hPa to around 1 K/decade at 1 hPa under the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario. In general, the simulated ozone evolution is mainly determined by decreases in halogen concentrations and continued cooling of the global stratosphere due to increases in greenhouse gases (GHGs). Column ozone is projected to increase as stratospheric halogen concentrations return to 1980s levels. Because of ozone increases in the middle and upper stratosphere due to GHG-induced cooling, total ozone averaged over midlatitudes, outside the polar regions, and globally, is projected to increase to 1980 values between 2035 and 2050 and before lower-stratospheric halogen amounts decrease to 1980 values. In the polar regions the CCMs simulate small temperature trends in the first and second half of the 21st century in midwinter. Differences in stratospheric inorganic chlorine (Cly) among the CCMs are key to diagnosing the intermodel differences in simulated ozone recovery, in particular in the Antarctic. It is found that there are substantial quantitative differences in the simulated Cly, with the October mean Antarctic Cly peak value varying from less than 2 ppb to over 3.5 ppb in the CCMs, and the date at which the Cly returns to 1980 values varying from before 2030 to after 2050. There is a similar variation in the timing of recovery of Antarctic springtime column ozone back to 1980 values. As most models underestimate peak Cly near 2000, ozone recovery in the Antarctic could occur even later, between 2060 and 2070. In the

  17. Assessment of SAGE Version 6.1 Ozone Data Quality

    NASA Technical Reports Server (NTRS)

    Wang, Hsiang J.; Cunnold, Derek M.; Thomason, Larry W.; Zawodny, Joseph M.; Bodeker, Greg E.

    2002-01-01

    The SAGE-II V6.1 ozone retrievals are shown to be of better precision at all levels and to be much more accurate than previous retrievals in the lower stratosphere below 20 km altitude. A filtering procedure for removing anomalous ozone profiles associated with volcanic aerosol/cloud effects and other identified artifacts in V6.1 ozone is described. The agreement between SAGE and ozonesondes in the mean is shown to be approximately 10% down to the tropopause. Relative to the sondes SAGE tends to slightly overestimate ozone (less than 5%) between 15 and 20 km altitude, and systematically underestimates ozone in the troposphere by approximately 30% in the regions between 8 km altitude and 2 km below the tropopause. The precisions (random errors) of SAGE ozone retrievals above 25 km altitude are estimated to be 4% or better; they are a factor of ten worse below 16 km altitude. Linear trends in the differences between coincident SAGE and ozonesondes measurement are generally less than 0.3 %/year and not significantly different from zero in 95% confidence intervals. Compared to V5.96 retrievals, ozone trend differences between 20 and 50 km altitude are approximately 0. 1 %/year, below 20 km altitude the SAGE II trends are more positive by approximately 0.2 %/year. For the 1984-1999 period the SAGE-II shows a localized ozone loss of -0.4(+/- 0.25) %/year (2gigma) in the tropics at 20 km altitude. In the lower stratosphere between 16 and 22 km altitudes, the SAGE shows significant ozone losses in the mid-latitudes in both Hemispheres during the 1979-1999 periods. The ozone trends range from -0.24(+/- 0.18) to -0.77(+/- 0.46) (2sigma)%/year. However in the 1984-1999 period, the downward trends are smaller (-0.07 to - 0.25 %/year) in this altitude range, and the trends in the integrated column from 12 to 17 km altitude in mid-latitudes (35 deg - 60 deg) are not significantly different from zero (0.1 +?- 0.6 (2sigma)%/year). Averaged over the tropics (20 deg S to 20 deg N

  18. Improvements in Total Column Ozone in GEOSCCM and Comparisons with a New Ozone-Depleting Substances Scenario

    NASA Technical Reports Server (NTRS)

    Oman, Luke D.; Douglass, Anne R.

    2014-01-01

    The evolution of ozone is examined in the latest version of the Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM) using old and new ozone-depleting substances (ODS) scenarios. This version of GEOSCCM includes a representation of the quasi-biennial oscillation, a more realistic implementation of ozone chemistry at high solar zenith angles, an improved air/sea roughness parameterization, and an extra 5 parts per trillion of CH3Br to account for brominated very short-lived substances. Together these additions improve the representation of ozone compared to observations. This improved version of GEOSCCM was used to simulate the ozone evolution for the A1 2010 and the newStratosphere-troposphere Processes and their Role in Climate (SPARC) 2013 ODS scenario derived using the SPARC Lifetimes Report 2013. This new ODS scenario results in a maximum Cltot increase of 65 parts per trillion by volume (pptv), decreasing slightly to 60 pptv by 2100. Approximately 72% of the increase is due to the longer lifetime of CFC-11. The quasi-global (60degS-60degN) total column ozone difference is relatively small and less than 1Dobson unit on average and consistent with the 3-4% larger 2050-2080 average Cly in the new SPARC 2013 scenario. Over high latitudes, this small change in Cly compared to the relatively large natural variabilitymakes it not possible to discern a significant impact on ozone in the second half of the 21st century in a single set of simulations.

  19. Coherence of longterm stratospheric ozone time series for the study of ozone recovery in the northern mid-latitudes

    NASA Astrophysics Data System (ADS)

    Nair, Prijitha J.; Godin-Beekmann, Sophie; Pazmino, Andrea

    2010-05-01

    Since mid-to late 1980s decreasing amounts of ozone concentration has been observed in northern mid-latitudes mainly due to the ozone depleting chlorofluorocarbon loading in the stratosphere. Recent works indicate the stabilization of ozone loss in the mid-latitudes, in the upper stratosphere in particular. In order to further investigate the evolution of ozone in the mid-latitudes, a coherent dataset is required. As a first step, we diagnose the long term evolution of ozone at Observatoire de Haute Provence (OHP - 43.93°N, 5.71°E), one of the northern mid-latitude stations. In this study, we present the inter comparison of ozone measurements from OHP LIDAR with collocated SBUV, SAGEII, HALOE, MLS and GOMOS satellite observations as well as the ground based Ozonesondes and Umkehr measurements. A detailed statistical study on the relative differences of the compared measurements is performed to check any specific drifts with time. In addition, the seasonal and annual averages of the relative deviations are also checked to quantify agreement among the data. On average, all instruments show their best agreement with LIDAR between 20 and 40 km, where the differences are within 5%. The agreement with SAGEII measurements are remarkably good since it falls within 1% at 17-41 km. A similar result is also found from the Ozonesondes comparison at 22-31 km. Most comparisons exhibit slightly larger deviations below 20 and above 42 km, of about 10%. The LIDAR masurements are also compared to Umkehr measurements by converting its ozone number density to Dobson units for each Umkehr layer. The analysis reveals a negative bias in Umkehr data within -10% except at layer 6 (around 30 km).

  20. Improvements in total column ozone in GEOSCCM and comparisons with a new ozone-depleting substances scenario

    NASA Astrophysics Data System (ADS)

    Oman, Luke D.; Douglass, Anne R.

    2014-05-01

    The evolution of ozone is examined in the latest version of the Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM) using old and new ozone-depleting substances (ODS) scenarios. This version of GEOSCCM includes a representation of the quasi-biennial oscillation, a more realistic implementation of ozone chemistry at high solar zenith angles, an improved air/sea roughness parameterization, and an extra 5 parts per trillion of CH3Br to account for brominated very short-lived substances. Together these additions improve the representation of ozone compared to observations. This improved version of GEOSCCM was used to simulate the ozone evolution for the A1 2010 and the new Stratosphere-troposphere Processes and their Role in Climate (SPARC) 2013 ODS scenario derived using the SPARC Lifetimes Report 2013. This new ODS scenario results in a maximum Cltot increase of 65 parts per trillion by volume (pptv), decreasing slightly to 60 pptv by 2100. Approximately 72% of the increase is due to the longer lifetime of CFC-11. The quasi-global (60°S-60°N) total column ozone difference is relatively small and less than 1 Dobson unit on average and consistent with the 3-4% larger 2050-2080 average Cly in the new SPARC 2013 scenario. Over high latitudes, this small change in Cly compared to the relatively large natural variability makes it not possible to discern a significant impact on ozone in the second half of the 21st century in a single set of simulations.

  1. Unprecedented 1993 ozone decrease over the United States from Dobson spectrophotometer observations

    SciTech Connect

    Komhyr, W.D.; Grass, R.D.; Evans, R.D.; Leonard, R.K.; Quincy, D.M. ); Hoffman, D.J.; Koenig, G.L. )

    1994-02-01

    Dobson spectrophotometer observations conducted since the early-to-mid 1960's at Bismarck, North Dakota; Caribou, Maine; Boulder, Colorado; Wallops Island, Virginia; Nashville, Tennessee; and at Fresno, California, since 1983, have revealed record low total ozone values during 1993. The tendency toward the low ozone values began in May 1992, but accelerated in early 1993. During January-August 1993, ozone monthly means at the stations were more than 2 standard deviations below long-term normal monthly means 72% of the time and more than 3 standard deviations below normals 42% of the time. On average, the January-April 1993 ozone values were 12.6% below normal, with ozone deficits as large as 18% observed at Caribou and Wallops Island in January. Of particular concern are unusually low ozone values that occur in summertime when solar ultraviolet insolation is high. Such record lows occurred at four of the six stations (Caribou, Wallops Island, Fresno, and Nashville). During May-August 1993, ozone was on average 8.5% below normal at these sites. Monthly means at these stations were, furthermore, lower on average by 3.7% than corresponding lowest values observed there in the past. The ozone decrease of 12.6% below normal at the six continental Dobson instrument stations during the winter and spring months of 1993 implies a possible average increase in UV erythemal radiation at that time of 16-25% above normal. The 8.5% decrease in ozone at Caribou, Wallops Island, Fresno, and Nashville, implies that on average, UV erythemal radiation may have been higher than normal at these stations during the summer of 1993 by 11-17%. 5 refs., 3 figs., 1 tab.

  2. Ozone transport commission developments

    SciTech Connect

    Joyce, K.M.

    1995-08-01

    On September 27, 1994, the states of the Ozone Transport Commission (OTC) signed an important memorandum of understanding (MOU) agreeing to develop a regional strategy for controlling stationary sources of nitrogen oxide emissions. Specifically, the states of the Ozone Transport Region, OTR, agreed to propose regulations for the control of NOx emissions from boilers and other indirect heat exchangers with a maximum gross heat input rate of at least 250 million BTU per hour. The Ozone Transport Region was divided into Inner, Outer and Northern Zones. States in the Outer Zone agreed to reduce NOx emissions by 55%. States in the Inner Zone agreed to reduce NOx emissions 65%. Facilities in both zones have the option to emit NOx at a rate no greater than 0.2 pounds per million Btu by May 1, 1999. This option provides fairness for the gas-fired plants which already have relatively low NOx emissions. Additionally, States in the Inner and Outer Zones agreed to reduce their NOx emissions by 75% or to emit NOx at a rate no greater than 0.15 pounds per million BTU by May 1, 2003. The Northern Zone States agree to reduce their rate of NOx emissions by 55% from base year levels by May 1, 2003, or to emit NOx at a rate no greater than 0.2 pounds per million BTU. As part of this MOU, States also agreed to develop a regionwide trading mechanism to provide a cost-effective mechanism for implementing the reductions.

  3. Ozone measurement systems improvements studies

    NASA Technical Reports Server (NTRS)

    Thomas, R. W.; Guard, K.; Holland, A. C.; Spurling, J. F.

    1974-01-01

    Results are summarized of an initial study of techniques for measuring atmospheric ozone, carried out as the first phase of a program to improve ozone measurement techniques. The study concentrated on two measurement systems, the electro chemical cell (ECC) ozonesonde and the Dobson ozone spectrophotometer, and consisted of two tasks. The first task consisted of error modeling and system error analysis of the two measurement systems. Under the second task a Monte-Carlo model of the Dobson ozone measurement technique was developed and programmed for computer operation.

  4. Spatial distribution of tropospheric ozone in national parks of California: interpretation of passive-sampler data.

    PubMed

    Ray, J D

    2001-09-28

    The National Park Service (NPS) has tested and used passive ozone samplers for several years to get baseline values for parks and to determine the spatial variability within parks. Experience has shown that the Ogawa passive samplers can provide +/-10% accuracy when used with a quality assurance program consisting of blanks, duplicates, collocated instrumentation, and a standard operating procedure that carefully guides site operators. Although the passive device does not meet EPA criteria as a certified method (mainly, that hourly values be measured), it does provide seasonal summed values of ozone. The seasonal ozone concentrations from the passive devices can be compared to other monitoring to determine baseline values, trends, and spatial variations. This point is illustrated with some kriged interpolation maps of ozone statistics. Passive ozone samplers were used to get elevational gradients and spatial distributions of ozone within a park. This was done in varying degrees at Mount Rainier, Olympic, Sequoia-Kings Canyon, Yosemite, Joshua Tree, Rocky Mountain, and Great Smoky Mountains national parks. The ozone has been found to vary by factors of 2 and 3 within a park when average ozone is compared between locations. Specific examples of the spatial distributions of ozone in three parks within California are given using interpolation maps. Positive aspects and limitations of the passive sampling approach are presented.

  5. 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.

  6. Simulations of ozone distributions in an aircraft cabin using computational fluid dynamics

    NASA Astrophysics Data System (ADS)

    Rai, Aakash C.; Chen, Qingyan

    2012-07-01

    Ozone is a major pollutant of indoor air. Many studies have demonstrated the adverse health effect of ozone and the byproducts generated as a result of ozone-initiated reactive chemistry in an indoor environment. This study developed a Computational Fluid Dynamics (CFD) model to predict the ozone distribution in an aircraft cabin. The model was used to simulate the distribution of ozone in an aircraft cabin mockup for the following cases: (1) empty cabin; (2) cabin with seats; (3) cabin with soiled T-shirts; (4) occupied cabin with simple human geometry; and (5) occupied cabin with detailed human geometry. The agreement was generally good between the CFD results and the available experimental data. The ozone removal rate, deposition velocity, retention ratio, and breathing zone levels were well predicted in those cases. The CFD model predicted breathing zone ozone concentration to be 77-99% of the average cabin ozone concentration depending on the seat location. The ozone concentration at the breathing zone in the cabin environment can better assess the health risk to passengers and can be used to develop strategies for a healthier cabin environment.

  7. Long-term tropical tropospheric ozone column retrievals using the Convective Clouds Differential (CCD) technique

    NASA Astrophysics Data System (ADS)

    Leventidou, Elpida; Ebojie, Felix; Eichmann, Kai-Uwe; Weber, Mark; Burrows, John P.

    2015-04-01

    Ozone influences most of the chemical reactions in the troposphere.Its tropospheric abundance can be retrieved using space-borne observations of vertically integrated ozone and cloud heights. The Convective Clouds Differential (CCD) technique (Ziemke et al., 1998 and Valks et al., 2014) takes advantage of the frequent occurrence of convective clouds in the western Pacific region by subtracting above-cloud ozone of this region from clear-sky ozone elsewhere to derive global monthly mean tropospheric amount. An important assumption is that the above-cloud ozone in the western Pacific simulates the stratospheric ozone and that the stratospheric ozone field is invariant with longitude; which is approximately true in the tropics. A CCD algorithm has been developed and is applied to optical remote sensing observations from three satellite instruments, so that a unique long-term record of monthly averaged tropical (20∘S, 20∘N) tropospheric vertically integrated ozone (1995-2012) is created. The validation of the CCD results with tropospheric ozone data from ozonesondes (Tompson et al., 2003) and Limb-Nadir matching observations (Ebojie et al. 2014) will be presented.

  8. Averaging Models: Parameters Estimation with the R-Average Procedure

    ERIC Educational Resources Information Center

    Vidotto, G.; Massidda, D.; Noventa, S.

    2010-01-01

    The Functional Measurement approach, proposed within the theoretical framework of Information Integration Theory (Anderson, 1981, 1982), can be a useful multi-attribute analysis tool. Compared to the majority of statistical models, the averaging model can account for interaction effects without adding complexity. The R-Average method (Vidotto &…

  9. Photochemical roles of rapid economic growth and potential abatement strategies on tropospheric ozone over South and East Asia in 2030

    NASA Astrophysics Data System (ADS)

    Chatani, S.; Amann, M.; Goel, A.; Hao, J.; Klimont, Z.; Kumar, A.; Mishra, A.; Sharma, S.; Wang, S. X.; Wang, Y. X.; Zhao, B.

    2014-04-01

    A regional air quality simulation framework including the Weather Research and Forecasting modelling system (WRF), the Community Multi-scale Air Quality modeling system (CMAQ), and precursor emissions to simulate tropospheric ozone over South and East Asia is introduced. Concentrations of tropospheric ozone and related species simulated by the framework are validated by comparing with observation data of surface monitorings, ozone zondes, and satellites obtained in 2010. The simulation demonstrates acceptable performance on tropospheric ozone over South and East Asia at regional scale. Future energy consumption, carbon dioxide (CO2), nitrogen oxides (NOx), and volatile organic compound (VOC) emissions in 2030 under three future scenarios are estimated. One of the scenarios assumes a business-as-usual (BAU) pathway, and other two scenarios consider implementation of additional energy and environmental strategies to reduce energy consumption, CO2, NOx, and VOC emissions in China and India. Future surface ozone under these three scenarios is predicted by the simulation. The simulation indicates future surface ozone significantly increases around India for a whole year and around north eastern China in summer. NOx is a main driver on significant seasonal increase of surface ozone, whereas VOC as well as increasing background ozone and methane is also an important factor on annual average of surface ozone in East Asia. Warmer weather around India is also preferable for significant increase of surface ozone. Additional energy and environmental strategies assumed in future scenarios are expected to be effective to reduce future surface ozone over South and East Asia.

  10. SWIFT: Semi-empirical and numerically efficient stratospheric ozone chemistry for global climate models

    NASA Astrophysics Data System (ADS)

    Kreyling, Daniel; Wohltmann, Ingo; Lehmann, Ralph; Rex, Markus

    2015-04-01

    The SWIFT model is a fast yet accurate chemistry scheme for calculating the chemistry of stratospheric ozone. It is mainly intended for use in Global Climate Models (GCMs), Chemistry Climate Models (CCMs) and Earth System Models (ESMs). For computing time reasons these models often do not employ full stratospheric chemistry modules, but use prescribed ozone instead. This can lead to insufficient representation between stratosphere and troposphere. The SWIFT stratospheric ozone chemistry model, focuses on the major reaction mechanisms of ozone production and loss in order to reduce the computational costs. SWIFT consists of two sub-models. 1) Inside the polar vortex, the model calculates polar vortex averaged ozone loss by solving a set of coupled differential equations for the key species in polar ozone chemistry. 2) The extra-polar regime, which this poster is going to focus on. Outside the polar vortex, the complex system of differential equations of a full stratospheric chemistry model is replaced by an explicit algebraic polynomial, which can be solved in a fraction of the time needed by the full scale model. The approach, which is used to construct the polynomial, is also referred to as repro-modeling and has been successfully applied to chemical models (Turanyi (1993), Lowe & Tomlin (2000)). The procedure uses data from the Lagrangian stratospheric chemistry and transport model ATLAS and yields one high-order polynomial for global ozone loss and production rates over 24h per month. The stratospheric ozone change rates can be sufficiently described by 9 variables. Latitude, altitude, temperature, the overhead ozone abundance, 4 mixing ratios of ozone depleting chemical families (chlorine, bromine, nitrogen-oxides and hydrogen-oxides) and the ozone concentrations itself. The ozone change rates in the lower stratosphere as a function of these 9 variables yield a sufficiently compact 9-D hyper-surface, which we can approximate with a polynomial. In the upper

  11. Role of tropospheric ozone increases in 20th-century climate change

    NASA Astrophysics Data System (ADS)

    Shindell, Drew; Faluvegi, Greg; Lacis, Andrew; Hansen, James; Ruedy, Reto; Aguilar, Elliot

    2006-04-01

    Human activities have increased tropospheric ozone, contributing to 20th-century warming. Using the spatial and temporal distribution of precursor emissions, we simulated tropospheric ozone from 1890 to 1990 using the NASA Goddard Institute for Space Studies (GISS) chemistry model. Archived three-dimensional ozone fields were then used in transient GISS climate model simulations. This enables more realistic evaluation of the impact of tropospheric ozone increases than prior simulations using an interpolation between preindustrial and present-day ozone. We find that tropospheric ozone contributed to the greater 20th-century warming in the Northern Hemisphere extratropics compared with the tropics and in the tropics compared with the Southern Hemisphere extratropics. Additionally, ozone increased more rapidly during the latter half of the century than the former, causing more rapid warming during that time. This is especially apparent in the tropics and is consistent with observations, which do not show similar behavior in the extratropics. Other climate forcings do not substantially accelerate warming rates in the tropics relative to other regions. This suggests that accelerated tropospheric ozone increases related to industrialization in the developing world have contributed to the accelerated tropical warming. During boreal summer, tropospheric ozone causes enhanced warming (>0.5°C) over polluted northern continental regions. Finally, the Arctic climate response to tropospheric ozone increases is large during fall, winter, and spring when ozone's lifetime is comparatively long and pollution transported from midlatitudes is abundant. The model indicates that tropospheric ozone could have contributed about 0.3°C annual average and about 0.4°C-0.5°C during winter and spring to the 20th-century Arctic warming. Pollution controls could thus substantially reduce the rapid rate of Arctic warming.

  12. Size-mediated foliar response to ozone in black cherry trees.

    PubMed

    Fredericksen, T S; Skelly, J M; Steiner, K C; Kolb, T E; Kouterick, K B

    1996-01-01

    Local ozone concentration and visible foliar injury were measured over the 1994 growing season on open-grown black cherry (Prunus serotina Ehrh.) trees of varying size (age) within forest stands and adjacent openings at a site in north-central Pennsylvania. Relationships were determined between visible ozone injury and ozone exposure, as well as calculated between injury and ozone uptake expressed as the product of stomatal conductance and ozone concentration. In addition, simultaneous measurements of visible symptoms and leaf gas exchange were also conducted to determine the correlation between visible and physiological injury and ozone exposure. By September, the amount of leaf area affected by visible foliar ozone injury was greatest for seedlings (46%), followed by canopy trees (20%) and saplings (15%). A large amount of variability in foliar ozone symptom expression was observed among trees within a size class. Sum40 and Sum60 (ozone concentration > 40 and > 60 nl liter(-1)) cumulative exposure statistics were the most meaningful indices for interpretation of foliar injury response. Seedlings were apparently more sensitive to ozone injury than larger trees because their higher rates of stomatal conductance resulted in higher rates of ozone uptake. Seedlings also had higher rates of early leaf abscission than larger trees with an average of nearly 30% of the leaves on a shoot abscised by 1 September compared to approximately 5% for larger trees. However, per unit ozone uptake into the leaf, larger trees exhibited larger amounts of foliar injury. The amount of visible foliar injury was negatively correlated (r(2) = 0.82) with net photosynthetic rates, but was not related to stomatal conductance. Net photosynthesis and stomatal conductance thus became uncoupled at high levels of visible foliar injury. PMID:15091453

  13. Comparison of satellite measurements of ozone and ozone trends

    SciTech Connect

    Rusch, D.W.; Clancy, R.T.; Bhartia, P.K. |

    1994-10-01

    Measurements of ozone retrieved from satellite instruments over the 1979-1991 period are compared. The instruments used are the total ozone mapping spectrometer (TOMS), the solar backscattered ultraviolet experiment (SBUV), and stratospheric aerosol and gas experiments (SAGE) I and II. Although there is good agreement between the absolute densities of ozone as measured by the various instruments, the long-term changes (1979-1990) disagree sharply as a function of pressure and in the integrated ozone amount. In the upper stratosphere, SBUV trends are negative with maximum values of about -1.5%/year at high latitudes. Combined SAGE I and II trends are slightly positive in this region and peak near 0.5%/year at equatorial latitudes. In the lower stratosphere, SBUV trends reflect small decreases in ozone, generally less than -0.4%/year except at high southern latitudes where the trends rearch values of approximately -1.5%/year. SAGE ozone trends exhibit large decreases particularly in the equatorial regions where decreases of 3-6%/year are seen at pressures between 60 and 90 mbar. At higher latitudes, SAGE trends are more comparable to SBUV trends in the lower stratosphere. Total ozone trends from TOMS and SBUV agree within their uncertainties. Near-zero trends are indicated at low latitudes, and larger, negative trends (approximately -0.5%/year) are indicated near the poles. The SAGE column ozone trends depend upon the base level altitude of integration but do not exhibit a strong latitude dependence.

  14. Ultraviolet Radiation and Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Stolarski, R.

    2003-01-01

    Ultraviolet radiation from the sun produces ozone in the stratosphere and it participates in the destruction of ozone. Absorption of solar ultraviolet radiation by ozone is the primary heating mechanism leading to the maximum in temperature at the stratopause. Variations of solar ultraviolet radiation on both the 27-day solar rotation period and the 11-year solar cycle affect ozone by several mechanisms. The temperature and ozone in the upper stratosphere respond to solar uv variations as a coupled system. An increase in uv leads to an increase in the production of ozone through the photolysis of molecular oxygen. An increase in uv leads to an increase in temperature through the heating by ozone photolysis. The increase in temperature leads to a partially-offsetting decrease in ozone through temperature-dependent reaction rate coefficients. The ozone variation modulates the heating by ozone photolysis. The increase in ozone at solar maximum enhances the uv heating. The processes are understood and supported by long-term data sets. Variation in the upper stratospheric temperatures will lead to a change in the behavior of waves propagating upward from the troposphere. Changes in the pattern of wave dissipation will lead to acceleration or deceleration of the mean flow and changes in the residual or transport circulation. This mechanism could lead to the propagation of the solar cycle uv variation from the upper stratosphere downward to the lower stratosphere. This process is not well-understood and has been the subject of an increasing number of model studies. I will review the data analyses for solar cycle and their comparison to model results.

  15. Nearly Perfect Spin Filter Based on a Wire of Half-Metallic (η5-C5H5)Ti (η8-C8H8)Ti Units

    NASA Astrophysics Data System (ADS)

    Zhu, Sicong; Fang, Jianming; Yao, Kailun; Wu, Yanqing

    2015-07-01

    Organic molecular devices show strong potential for future nanoelectronics applications, many of which require multifunction capability. Organometallic [(C5H5)Ti(C8H8)] n clusters are one of the few molecular material clusters that have been synthesized experimentally. Here we present a theoretical study of the spin-polarized transport on the clusters of [(C5H5)Ti(C8H8)] n by using nonequilibrium Green's functions combined with the density-functional theory. Results indicate that one-dimensional, organic (η5-C5H5)Ti (η8-C8H8)Ti wire has unique half-metallic properties with 100% spin polarization near the Fermi level in the ground state. We predict that finite-layer [(C5H5)Ti (C8H8)] n clusters coupled to gold electrodes exhibit a near-perfect spin-filter effect. Furthermore, due to the large spin coherence originated from its organic nature, these devices possess a spin-valve effect with large magnetoresistance. Our findings suggest that such a multifunctional molecular device is an excellent candidate for future molecule-based spintronic applications.

  16. A survey of ozone concentrations in rural western Utah: unexpected results and spatial heterogeneity from 2010-2013

    NASA Astrophysics Data System (ADS)

    Arens, S. J.; Harper, K.

    2013-12-01

    Ozone concentrations and meteorological variables were monitored at eleven sites in rural western Utah during late spring through summer of 2010-2013 to determine regional background concentrations of ozone and to determine attainment or nonattainment of the ozone National Ambient Air Quality Standard (NAAQS). Ozone concentrations have been monitored along the Wasatch Front of Utah (Logan, Ogden, Salt Lake City and Provo) for 30 years by the Utah Division of Air Quality (DAQ), but no ozone data from outside the cities of Wasatch Front existed prior to 2010. All rural sites, except Badger Springs, west of St. George, UT, were in attainment of the ozone NAAQS, which is 75 ppb averaged over 8 hours. However, ozone concentrations were higher than expected at seven of the eleven sites. All eleven sites were located in either small rural towns or uninhabited areas of western Utah, which were distant from anthropogenic emissions of ozone precursors. In 2010, ozone concentrations were relatively low along the Wasatch Front of Utah. Ozone concentrations exceeded 65 ppb for one day at three of four rural sites. Ozone concentrations at two of the four sites were generally in the range of expected rural ozone concentrations of 50-60 ppb. Ozone concentrations during 2011-2012 were higher throughout Utah compared to 2010. In 2011, 8-hour ozone concentrations exceeded 70 ppb for at least one day at four of five sites. The maximum 8-hour ozone concentration was 78 ppb, observed at Lytle Ranch, west of St. George, UT. Ozone concentrations at only one rural Utah site were in the expected range of 50-60 ppb. Ozone concentrations during 2012 were the highest observed during the four years of the study with 8-hour ozone concentrations exceeding 75 ppb at three of five rural sites and exceeding 70 ppb for at least four days at four of five sites. Although data collected was not considered regulatory by the EPA, the ozone NAAQS was exceeded at Badger Springs in southwestern Utah. Ozone

  17. Averaging Internal Consistency Reliability Coefficients

    ERIC Educational Resources Information Center

    Feldt, Leonard S.; Charter, Richard A.

    2006-01-01

    Seven approaches to averaging reliability coefficients are presented. Each approach starts with a unique definition of the concept of "average," and no approach is more correct than the others. Six of the approaches are applicable to internal consistency coefficients. The seventh approach is specific to alternate-forms coefficients. Although the…

  18. What can we learn about baryon-baryon interaction from hypernuclei {sub {lambda}}{sup 6}H and {sub {lambda}}{sup 8}H?

    SciTech Connect

    Majling, L. Gmuca, S.

    2007-09-15

    At the LHE JINR, an original approach to hypernuclear experiments was elaborated to produce relativistic hypernuclei. The production cross sections and lifetimes, {tau}, of {sub {lambda}}{sup 3}H and {sub {lambda}}{sup 4}H were measured successfully. The results of recent experiments on {sup 5}H and {sup 7}H nuclei suggest that the hypernucleus {sub {lambda}}{sup 6}H might be stable and that this may be the case even for {sub {lambda}}{sup 8}H. The unique quality of the spectrometer SPHERE may be used to identify unambiguously the isotopes of hyperhydrogen-through their pionic decay {sub {lambda}}{sup A}H {sup {yields}} {pi}{sup -} + {sup A}He-including the new hypernuclei {sub {lambda}}{sup 6}H and {sub {lambda}}{sup 8}H with extreme values of N/Z of 4 and 6, respectively. The confirmation of the very existence of these neutron-rich hypernuclei would be a strong motivation to search for their spectra in strangeness and double-charge-exchange reactions (K{sub stop}{sup -}, {pi}{sup +}) at FINUDA or ({pi}{sup -}, K{sup +}) at J-PARC. It is very probable that, similarly as in {sub {lambda}}{sup 4}H, there is a low-lying state 1{sup +} also in {sub {lambda}}{sup 6}H and {sub {lambda}}{sup 8}H. If their electromagnetic width (M1) is small enough, we could see two different values of {tau} for {sub {lambda}}{sup 6}H and/or {sub {lambda}}{sup 8}H. We investigate the spacings of the 1{sup +} and 0{sup +} states of {sub {lambda}}{sup 4}H, {sub {lambda}}{sup 6}H, and {sub {lambda}}{sup 8}H. The understanding of the structure of isospin asymmetric systems plays a key role in the description of systems as diverse as neutron-rich nuclei and neutron matter.

  19. The Average of Rates and the Average Rate.

    ERIC Educational Resources Information Center

    Lindstrom, Peter

    1988-01-01

    Defines arithmetic, harmonic, and weighted harmonic means, and discusses their properties. Describes the application of these properties in problems involving fuel economy estimates and average rates of motion. Gives example problems and solutions. (CW)

  20. Plant responses to tropospheric ozone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tropospheric ozone is the second most abundant air pollutant and an important component of the global climate change. Over five decades of research on the phytotoxicity of ozone in model plants systems, crop plants and forest trees have provided some insight into the physiological, biochemical and m...

  1. Nonaqueous ozonation of vulcanized rubber

    SciTech Connect

    Serkiz, S.M.

    1999-12-07

    A process and resulting product are provided in which a solid particulate, such as vulcanized crumb rubber, has the surface functional groups oxidized by ozonation using a nonpolar solvent. The ozonation process renders the treated crumb rubber more suitable for use in new rubber formulations. As a result, larger loading levels of the treated crumb rubber can be used in new rubber mixtures.

  2. Rocket ozone sounding network data

    NASA Technical Reports Server (NTRS)

    Wright, D. U.; Krueger, A. J.; Foster, G. M.

    1979-01-01

    During the period March 1977 through May 1977, three regular monthly ozone profiles were measured at Wallops Flight Center and three regular monthly ozone profiles were measured at the Churchill Research Range. One additional flight was conducted at Wallops Flight Center in support of Nimbus 4 SBUV. Data results and flight profiles for the period covered are presented.

  3. Atmospheric iodine abates smog ozone.

    PubMed

    HAMILTON, W F; LEVINE, M; SIMON, E

    1963-04-12

    Traces of iodine in test samples of irradiated photochemical smog atmospheres either inhibit ozone formation or lower its concentration. Eye and respiratory irritation are reduced qualitatively. Iodine is more effective in suppressing ozone in a photochemical smog atmosphere than it is in purified air.

  4. Modelling the Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Crutzen, P. J.; Bruhl, C.

    1988-01-01

    Researchers performed model calculations of the ozone depletions taking place in the Antarctic lower stratosphere. Making the assumption that odd nitrogen is frozen out on stratospheric haze particles, an analysis is given of how much homogeneous reactions can contribute to ozone loss during September-October. Comparisons with observations indicate the potential importance of reactions with HCl in the polar stratospheric cloud particles.

  5. Nonaqueous ozonation of vulcanized rubber

    DOEpatents

    Serkiz, Steven M.

    1999-01-01

    A process and resulting product is provided in which a solid particulate, such as vulcanized crumb rubber, has the surface functional groups oxidized by ozonation using a nonpolar solvent. The ozonation process renders the treated crumb rubber more suitable for use in new rubber formulations. As a result, larger loading levels of the treated crumb rubber can be used in new rubber mixtures.

  6. Rocket ozone sounding network data

    NASA Technical Reports Server (NTRS)

    Wright, D. U.; Krueger, A. J.; Foster, G. M.

    1978-01-01

    During the period December 1976 through February 1977, three regular monthly ozone profiles were measured at Wallops Flight Center, two special soundings were taken at Antigua, West Indies, and at the Churchill Research Range, monthly activities were initiated to establish stratospheric ozone climatology. This report presents the data results and flight profiles for the period covered.

  7. Simplified ozone detection by chemiluminescence

    NASA Technical Reports Server (NTRS)

    Conway, E. J.; Rogowski, R. S.; Richards, R. R.

    1977-01-01

    Ozone is detected by film coated with solid, such as rubrene, that reacts with ozone to degree proportional to concentration in sample gas. Gas flow is stopped, and film is heated to produce light (chemiluminescence) in proportion to amount of reacted material on sensor.

  8. Impact of regional meteorology on ozone levels in the Lake Tahoe Basin

    NASA Astrophysics Data System (ADS)

    Rayne, Sandra; Gertler, Alan; Zielinska, Barbara; Bytnerowicz, Andrzej; Burley, Joel; Kaplan, Michael

    2016-07-01

    The Lake Tahoe Basin is located on the California-Nevada border and occasionally experiences elevated levels of ozone (O3) exceeding the California Air Resources Board ambient air quality standard (8-h average). Previous studies indicate that both the local generation and long-range transport from out-of-basin sources are important in contributing to O3 exceedances, but little is known about the impact of regional meteorology on O3 source regions. To develop a better understanding of the factors affecting O3 levels and sources in the Lake Tahoe Basin, a comprehensive field study was performed in the summer of 2010. Included in this effort was a meteorological analysis addressing potential regional meteorological influences leading to periods of elevated levels of O3. Three approaches were used to conduct the analysis: (1) regional atmospheric pressure difference (i.e., the Washoe Zephyr) to access potential transport, (2) back trajectory modeling using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to determine where the air masses originated and, (3) composite soundings to evaluate in-Basin atmospheric influences. These analyses indicate the Washoe Zephyr did not strongly impact O3 levels; however, higher O3 levels were found to correspond with both a more southerly wind component and a dip in dew point temperature around 400 hPa. The results also indicate that if transport does occur, it is more likely to come from the San Joaquin Valley and move to the southern part of the Basin, rather than originating in the large cities to the west (i.e., Sacramento and San Francisco).

  9. 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.

  10. An assessment of ozone concentrations within and near the Lake Tahoe Air Basin

    NASA Astrophysics Data System (ADS)

    Dolislager, Leon J.; VanCuren, Richard; Pederson, James R.; Lashgari, Ash; McCauley, Eileen

    2012-01-01

    The Lake Tahoe Atmospheric Deposition Study (LTADS) was conducted by the Air Resources Board of the State of California (CARB) primarily to generate refined estimates of the atmospheric deposition of nitrogen, phosphorous, and particulate matter directly to Lake Tahoe, which straddles the border between the states of California and Nevada near Reno, Nevada. The enhanced air quality monitoring during LTADS also included ozone measurements, which yielded additional insights into atmospheric processes and the role of transport in determining ozone concentrations within the Lake Tahoe Air Basin. The Lake Tahoe Air Basin is located generally downwind of air basins with major emissions of ozone precursors (e.g., VOCs, NOx), capable of generating significant ozone concentrations. Furthermore, vegetation on the western slope of the Sierra Nevada contribute biogenic organic compounds to the air mass. Ozone concentrations within the Tahoe Basin infrequently exceed the local 1-h threshold set to protect forest health (0.08 ppm) and the California 8-h ambient air quality standard (0.070 ppm). A concern then is the potential contribution of regional emission sources to the ozone concentrations observed in the Tahoe Basin. The ozone data collected during LTADS helped to better characterize the relative contribution of local and regional pollution sources to ozone air quality within the Tahoe Basin. The data indicate potential 1- or 2-day intact transport on rare occasions but generally the mixing of the atmosphere over the Sierra Nevada disperses the anthropogenic ozone throughout the boundary layer, which is generally more than a kilometer or two deep during the day. The data analysis indicates that emissions from upwind air basins add to the atmospheric burden of ozone concentrations, raising the regional concentrations in the Sierra Nevada. Given the large background and upwind enhancements relative to the ambient air quality standards, the local contribution does not need to

  11. Source attribution of tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Butler, T. M.

    2015-12-01

    Tropospheric ozone is a harmful pollutant with adverse effects on human health and ecosystems. As well as these effects, tropospheric ozone is also a powerful greenhouse gas, with an anthropogenic radiative forcing one quarter of that of CO2. Along with methane and atmospheric aerosol, tropospheric ozone belongs to the so-called Short Lived Climate forcing Pollutants, or SLCP. Recent work has shown that efforts to reduce concentrations of SLCP in the atmosphere have the potential to slow the rate of near-term climate change, while simultaneously improving public health and reducing crop losses. Unlike many other SLCP, tropospehric ozone is not directly emitted, but is instead influenced by two distinct sources: transport of air from the ozone-rich stratosphere; and photochemical production in the troposphere from the emitted precursors NOx (oxides of nitrogen), CO (Carbon Monoxide), and VOC (volatile organic compounds, including methane). Better understanding of the relationship between ozone production and the emissions of its precursors is essential for the development of targeted emission reduction strategies. Several modeling methods have been employed to relate the production of tropospheric ozone to emissions of its precursors; emissions perturbation, tagging, and adjoint sensitivity methods all deliver complementary information about modelled ozone production. Most studies using tagging methods have focused on attribution of tropospheric ozone production to emissions of NOx, even though perturbation methods have suggested that tropospheric ozone is also sensitive to VOC, particularly methane. In this study we describe the implementation into a global chemistry-climate model of a scheme for tagging emissions of NOx and VOC with an arbitrary number of labels, which are followed through the chemical reactions of tropospheric ozone production in order to perform attribution of tropospehric ozone to its emitted precursors. Attribution is performed to both

  12. Direct measurements of tropospheric ozone from TOMS data

    NASA Technical Reports Server (NTRS)

    Hudson, Robert D.

    1993-01-01

    In the past year, we have made measurements of the tropospheric total column of ozone during the biomass burning season in Africa (August to October). Fishman et. al. had reported previously that by taking a time average of the low spatial resolution data from TOMS (Total Ozone Mapping Spectrometer) on Nimbus-7 (referred to as the Grid-T data set), during the biomass burning season in Africa, a plume of ozone extends from the East coast of Africa into the Atlantic. In this report, we present an analysis that we have made using the measured TOMS radiances taken from the High Density TOMS data set (referred as the HDT data set), which examines this plume in more detail.

  13. The neuron network forecasting dynamics of the ozone layer

    NASA Astrophysics Data System (ADS)

    Lankin, J.; Sakash, I.

    One of the major tasks today is preserving the Earth's ozonosphere, - because the ozone layer serves as a screen, filtering a part of harmful solar ultraviolet radiation. During the recent decades, some scientists of different countries have paid their attention to significant decrease of ozone density in the atmosphere above certain points of the Earth's surface. If the average ozone concentration in the atmosphere is about 300-350 D. u., its annual drop above the Antarctic continent follows to the values of concentration even of 90 D. u. Such -- and similar -- publications have triggered widespread public interest (tied to the global environmental crisis); the phenomenon has been named "an ozone hole" and followed by an explosion of scientific interest to ozonospheric studies. In order to simulate hourly TOC oscillations, the ground observation data (City of Tomsk, Russia - 56 N and 84 E) has been used. The following models of ÒÎÑ have been designed: hourly (hourly CCO values are been forecasted for March 30 and 31, 1996-99), diurnal (June 14 -- October 31, 1998), monthly (September 1975 -- August 1977) and annual (1975-1982) ones. The study performed has proven a high degree of effectiveness of using neuron networks for simulating the dynamics of the Earth's ozonosphere. A real opportunity to design local prognostic models using neuronets is revealed. In future, some three-dimentional global models of ozonosphere and atmosphere may be established. However, there a number of cases of significant variations of the ozone concentration time rows for different seasons and time spans. Studying and predicting such changes is of the great interest in terms of better understanding the specifics of developing the atmospheric processes and improving the technology of the forecast. The study is focused upon revealing the precursors of the spontaneous "ozone hole" (areas of the lowered concentration of ozone) formation in the stratosphere and based on neuron network

  14. Ozone adsorption on carbon nanoparticles

    NASA Astrophysics Data System (ADS)

    Chassard, Guillaume; Gosselin, Sylvie; Visez, Nicolas; Petitprez, Denis

    2014-05-01

    Carbonaceous particles produced by incomplete combustion or thermal decomposition of hydrocarbons are ubiquitous in the atmosphere. On these particles are adsorbed hundreds of chemical species. Those of great concern to health are polycyclic aromatic hydrocarbons (PAHs). During atmospheric transport, particulate PAHs react with gaseous oxidants. The induced chemical transformations may change toxicity and hygroscopicity of these potentially inhalable particles. The interaction between ozone and carbon particles has been extensively investigated in literature. However ozone adsorption and surface reaction mechanisms are still ambiguous. Some studies described a fast catalytic decomposition of ozone initiated by an atomic oxygen chemisorption followed by a molecular oxygen release [1-3]. Others suggested a reversible ozone adsorption according to Langmuir-type behaviour [4,5]. The aim of this present study is a better understanding of ozone interaction with carbon surfaces. An aerosol of carbon nanoparticles was generated by flowing synthetic air in a glass tube containing pure carbon (primary particles < 50 nm), under magnetic stirring. The aerosol was then mixed with ozone in an aerosol flow tube. Ozone uptake experiments were performed with different particles concentrations with a fixed ozone concentration. The influence of several factors on kinetics was examined: initial ozone concentration, particle size (50 nm ≤ Dp ≤ 200 nm) and competitive adsorption (with probe molecule and water). The effect of initial ozone concentration was first studied. Accordingly to literature, it has been observed that the number of gas-phase ozone molecules lost per unit particle surface area tends towards a plateau for high ozone concentration suggesting a reversible ozone adsorption according to a Langmuir mechanism. We calculated the initial reaction probability between O3 and carbon particles.An initial uptake coefficient of 1.10-4 was obtained. Similar experiments were

  15. Latest tendency in the Antarctic ozone longitudinal distribution

    NASA Astrophysics Data System (ADS)

    Milinevsky, Gennadi; Grytsai, Asen; Klekociuk, Andrew; Evtushevsky, Olexander

    2014-05-01

    Significant ozone depletion was observed within the southern polar vortex during spring in the 1980s - early 1990s. Later, a stabilization in total ozone levels and ozone hole area has been observed. Atmosphere models predict a consequent recovery of the Antarctic ozone. Nevertheless, identification of the long-term processes is complicated by high interannual variability hiding their general regularities. In particular, a large stratosphere warming in 2002 resulted in significant increase in total ozone levels. The Antarctic ozone hole is formed inside polar stratospheric vortex, which is under influence of large-scale planetary waves. The components of the quasi-stationary wave (QSW) in the spring Southern Hemisphere (SH) stratosphere is mainly contributed by zonal wave number 1 which in turn determines the location of the total ozone extremes in spring: QSW minimum (maximum) is located in the South Atlantic (Australian) sector. In our work the satellite data of TOMS/Nimbus-7, TOMS/Earth Probe and OMI/Aura (http://ozoneaq.gsfc.nasa.gov/) have been used to investigate longitudinal distribution of the total ozone in Antarctic region. The gap in these satellite observations (1993-1995) was filled by the Multi-Sensor Reanalysis data (http://www.temis.nl/). Ozone distribution in the SH high and mid latitudes 80-50S were analyzed for southern spring season including months from September to November. The zonal distribution is considered along seven latitude circles from 80S to 50S with step of five degrees. To distinguish long-term processes and to obtain a quasi-stationary pattern, daily September - November ozone was averaged. Our previous study demonstrated a systematic eastward shift of the QSW minimum region. In this study, we extended the analysis to 2013 and obtained new results that exhibited a probable cessation in that eastward shift. Polynomial fit for all chosen latitudes is even evidence of a change in the tendency to opposite. It more time needs to

  16. 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

  17. Measures of ozone concentrations using passive sampling in forests of South Western Europe.

    PubMed

    Sanz, M J; Calatayud, V; Sánchez-Peña, G

    2007-02-01

    Ambient ozone concentrations were measured with passive samplers in the framework of the EU and UN/ECE Level II forest monitoring programme. Data from France, Italy, Luxembourg, Spain and Switzerland are reported for 2000-2002, covering the period from April to September. The number of plots increased from 67 in 2000 to 83 in 2002. The year 2001 experienced the highest ozone concentrations, reflecting more stable summer meteorological conditions. Average 6-month ozone concentrations above 45 ppb were measured this year in 40.3% of the plots, in contrast with the less than 21% measured in the other 2 years. Gradients of increasing ozone levels were observed from North to South and with altitude. Comments are made on the regional trends and on the time frame of the higher ozone episodes. Also, some recommendations enabling a better comparison between plots are provided.

  18. Effects of the 2004 El Nino on Tropospheric Ozone and Water Vapor

    NASA Technical Reports Server (NTRS)

    Chandra, S.; Ziemke, J. R.; Schoeberl, M. R.; Froidevaux, L.; Read, W. G.; Levelt, P. F.; Bhartia, P. K.

    2007-01-01

    The global effects of the 2004 El Nino on tropospheric ozone and H2O based on Aura OM1 and MLS measurements are analyzed. Although it was a weak El Nino from a historical perspective, it produced significant changes in these parameters in tropical latitudes. Tropospheric ozone increased by 10-20% over most of the western Pacific region and decreased by about the same amount over the eastern Pacific region. H2O in the upper troposphere showed similar changes but with opposite sign. These zonal changes in tropospheric ozone and H2O are caused by the eastward shift in the Walker circulation in the tropical pacific region during El Nino. For the 2004 El Nino, biomass burning did not have a significant effect on the ozone budget in the troposphere unlike the 1997 El Nino. Zonally averaged tropospheric column ozone did not change significantly either globally or over the tropical and subtropical latitudes.

  19. The sensitivity of modeled ozone to the temporal distribution of point, area, and mobile source emissions in the eastern United States

    NASA Astrophysics Data System (ADS)

    Castellanos, Patricia; Stehr, Jeffrey W.; Dickerson, Russell R.; Ehrman, Sheryl H.

    Ozone remains one of the most recalcitrant air pollution problems in the US. Hourly emissions fields used in air quality models (AQMs) generally show less temporal variability than corresponding measurements from continuous emissions monitors (CEM) and field campaigns would imply. If emissions control scenarios to reduce emissions at peak ozone forming hours are to be assessed with AQMs, the effect of emissions' daily variability on modeled ozone must be understood. We analyzed the effects of altering all anthropogenic emissions' temporal distributions by source group on 2002 summer-long simulations of ozone using the Community Multiscale Air Quality Model (CMAQ) v4.5 and the Carbon Bond IV (CBIV) chemical mechanism with 12 km resolution. We find that when mobile source emissions were made constant over the course of a day, 8-h maximum ozone predictions changed by ±7 parts per billion by volume (ppbv) in many urban areas on days when ozone concentrations greater than 80 ppbv were simulated in the base case. Increasing the temporal variation of point sources resulted in ozone changes of +6 and -6 ppbv, but only for small areas near sources. Changing the daily cycle of mobile source emissions produces substantial changes in simulated ozone, especially in urban areas at night; results suggest that shifting the emissions of NO x from day to night, for example in electric powered vehicles recharged at night, could have beneficial impacts on air quality.

  20. Seasonal Variability in Tropospheric Ozone Distribution Over Qatar

    NASA Astrophysics Data System (ADS)

    Ayoub, Mohammed; Ackermann, Luis

    2015-04-01

    We report on the vertical distribution and seasonal variability in tropospheric ozone over the Middle East through one year of weekly ozonesondes launched from Doha, Qatar during 2014. A total of 49 2Z-V7 DMT/EN-SCI Electrochemical Concentration Cell (ECC) ozonesondes employing a 1% buffered potassium iodide solution (KI), coupled with iMet-1-RS GPS radiosondes were launched around 1300 local time. The authors used the SkySonde telemetry software (developed by CIRES and NOAA/ESRL) and developed robust in-house data quality assurance and validation methodologies. The average height of the thermal tropopause is between 15-17.5 km (125-85 hPa). Monthly average relative humidity around the tropopause shows an enhancement during the months of June through the beginning of October. Monthly average temperature profiles show the development of the subtropical subsidence inversion around 5-6 km (450-520 hPa) between the months of April through October. The subsidence inversion is strongest during the months of June and July and is accompanied by a sharp drop in relative humidity over a 100-300 m in the vertical. The monthly average ozone background concentration between the Planetary Boundary Layer (PBL) height and the subsidence inversion increases from 50 ppb in the winter to almost 80 ppb in the summer months. An enhancement of up to 50% in the average ozone in the mid-to-upper troposphere (above the subsidence inversion) is strongest during the summer months (June through September) and results in average concentrations between 80-100 ppb. In the upper troposphere (above 13 km/200 hPa) ozone concentrations are highest during the spring and summer months. This is coupled with a drop in the average height of the tropopause. HYSPLIT back-trajectory analysis shows the enhancement in mid-to-upper tropospheric ozone in the summer is due to persistent high pressure over the Middle East between the months of June through September. Evidence of Stratosphere-Troposphere Exchange

  1. Analysis of atmospheric ozone levels at commercial airplane cruise altitudes in winter and spring 1976-77. Technical paper

    SciTech Connect

    Holdeman, J.D.; Nastrom, G.D.

    1981-04-01

    It has been speculated that the ozone sickness experienced by some airline passengers and crew members during the winter and spring of 1976-77 were induced by abnormally high concentrations of ambient atmospheric ozone. To investigate the possibility that 1976-77 was anomalous, ozone measurements from balloons for up to 13 years and from Global Atmospheric Sampling Program (GASP) equipped aircraft for 3 years have been studied. The analyses show that the winter and spring seasons of 1976-77 were averaged statistically, and no evidence was found to suggest that there was more than a usual variation in the frequency that commercial airplanes encountered high ambient ozone concentrations.

  2. The Sodankyla Total Ozone Intercomparison and Validation Campaign: ozonesonde observations

    NASA Astrophysics Data System (ADS)

    Kivi, Rigel; Bojkov, Bojan; Kyro, Esko; Heikkinen, Pauli; McGee, Thomas; Brinksma, Ellen

    Ozonesondes are widely used to validate satellite borne atmospheric remote sensing measurements. Sonde data quality depends on the sonde type and the preparation procedure. It is important to assess the accuracy of sonde measurements to be used for the validation of satellite instruments. Here we investigate the performance of ENSCI ozonesondes during the Sodankyl¨ a Total Ozone Intercomparison and Validation Campaign (SAUNA), which took place in March -April 2006 and in February-March 2007 in Sodankyl¨, Finland (67.4 ° N, 26.6 ° E). The cama paign provided a large set of ground-based observational data to validate the performance of ground-based and satellite borne ozone sensors at a high latitude site. We present comparisons with satellite instruments, an ozone lidar and Brewer spectrophotometers and results from dual ozonesonde flights. During March 22- April 14, 2006 we performed altogether 31 balloon flights, and from February 1 to March 3, 2007 in total 54 flights. The balloon launches were timed to the ozone measurements on board the NASA Aura satellite. In each payload an ENSCI ozonesonde was flown prepared with the cathode solution concentration of 0.5% KI. In addition, we made a series of dual sonde flights, which included also a SPC ozonesonde with the cathode solution concentration of 1 % KI. As a result of all dual sonde flights we found relative difference less than 2 % between the sonde types in the stratosphere, and from 3 to 4 % in the troposphere. Total ozone from sondes was in good agreement with the Ozone Monitoring Instrument (OMI) observations on board the Aura satellite. During the first campaign phase the average ratio OMI/ sonde was 0.99 +/- 0.02 % and during the second phase 1.00 +/- 0.05 %. The average ratio Brewer/sonde was 1.00 +/- 0.02 %.

  3. Nitroaromatic hydrocarbon ozonation in water. 1: Single ozonation

    SciTech Connect

    Beltran, F.J.; Encinar, J.M.; Alonso, M.A.

    1998-01-01

    Single ozonation of two nitroaromatic hydrocarbons (nitrobenzene and 2,6-dinitrotoluene) under different experimental conditions (ozone feed rate, pH, temperature, hydroxyl radical scavengers) has been studied. The absence of hydroxyl radical scavengers, pHs 7--9, and temperatures below 30 C are optimum conditions for nitroaromatic removal. Due to the importance of hydroxyl radical reactions, removal rates in natural water are much lower than those observed in laboratory ultrapure water. Rate constants of the direct reaction between ozone and nitroaromatic hydrocarbons at 20 C have been found to be lower than 6 M{sup {minus}1} s{sup {minus}1}. More than 99% of nitroaromatic removal is due to hydroxyl radical oxidation. Single ozonation of nitroaromatics can then be classified as a real advanced oxidation technology. Nitrophenols, compounds very reactive toward ozone and hydroxyl radicals, and 2,6-dinitrobenzaldehyde, identified in the single ozonation of nitrobenzene and 2,6-dinitrotoluene, respectively, are some of the first intermediates of single ozonation.

  4. Stratospheric ozone in the 21st Century: The chlorofluorocarbon problem

    SciTech Connect

    Rowland, F.S. )

    1991-04-01

    Ozone (O{sub 3}) exists in a dynamic equilibrium in the stratosphere, balanced between formation by solar ultraviolet photolysis ({lambda} < 242 nm) of molecular O{sub 2} (O + O{sub 2} {yields} O{sub 3}) and destruction by various chemical processes including several chain reaction sequences triggered by HO{sub x}, NO{sub x}, and ClO{sub x} radicals. The ozone dissipates over Antarctica by November through northward mixing, only to begin reappearing in late August of the following year. Substantial ozone losses have also appeared, although not as spectacularly as over Antarctica, in the Northern Hemisphere's temperate and polar regions. The primary cause for the Antarctic ozone loss, and the probable cause for the northern losses, is the increasing concentration in the stratosphere of anthropogenic chlorine, especially chlorine released by solar UV photolysis from chlorofluorocarbon (CFC) compounds such as CCl{sub 2}F{sub 2} (CFC-12), CCl{sub 3}F (CFC-11) and CCl{sub 2}FCClF{sub 2} (CFC-113). Because these molecules have average atmospheric lifetimes of many decades, excess anthropogenic chlorine will persist in the stratosphere for comparable time periods, and the Antarctic ozone hole will be an important atmospheric phenomenon throughout the 21st century.

  5. Assessing the public health benefits of reduced ozone concentrations.

    PubMed Central

    Levy, J I; Carrothers, T J; Tuomisto, J T; Hammitt, J K; Evans, J S

    2001-01-01

    In this paper we examine scientific evidence and related uncertainties in two steps of benefit-cost analyses of ozone reduction: estimating the health improvements attributable to reductions in ozone and determining the appropriate monetary values of these improvements. Although substantial evidence exists on molecular and physiologic impacts, the evidence needed to establish concentration-response functions is somewhat limited. Furthermore, because exposure to ozone depends on factors such as air conditioning use, past epidemiologic studies may not be directly applicable in unstudied settings. To evaluate the evidence likely to contribute significantly to benefits, we focus on four health outcomes: premature mortality, chronic asthma, respiratory hospital admissions, and minor restricted activity days. We determine concentration-response functions for these health outcomes for a hypothetical case study in Houston, Texas, using probabilistic weighting reflecting our judgment of the strength of the evidence and the possibility of confounding. We make a similar presentation for valuation, where uncertainty is due primarily to the lack of willingness-to-pay data for the population affected by ozone. We estimate that the annual monetary value of health benefits from reducing ozone concentrations in Houston is approximately $10 per person per microgram per cubic meter (24-hr average) reduced (95% confidence interval, $0.70-$40). The central estimate exceeds past estimates by approximately a factor of five, driven by the inclusion of mortality. We discuss the implications of our findings for future analyses and determine areas of research that might help reduce the uncertainties in benefit estimation. PMID:11748028

  6. Southern Hemisphere Additional Ozonesondes (SHADOZ) Ozone Climatology (2005-2009): Tropospheric and Tropical Tropopause Layer (TTL) Profiles with Comparisons to Omi-based Ozone Products

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Miller, Sonya K.; Tilmes, Simone; Kollonige, Debra W.; Witte, Jacquelyn C.; Oltmans, Samuel J.; Johnson, Brian J.; Fujiwara, Masatomo; Schmidlin, F. J.; Coetzee, G. J. R.; Komala, Ninong; Maata, Matakite; bt Mohammad, Maznorizan; Nguyo, J.; Mutai, C.; Ogino, S-Y; Da Silva, F. Raimundo; Paes Leme, N. M.; Posny, Francoise; Scheele, Rinus; Selkirk, Henry B.; Shiotani, Masato; Stubi, Rene; Levrat, Gilbert; Calpini, Bertrand; Thouret, Valerie; Tsuruta, Haruo; Canossa, Jessica Valverde; Voemel, Holger; Yonemura, S.; Andres Diaz, Jorge; Tan Thanh, Nguyen T.; Thuy Ha, Hoang T.

    2012-01-01

    We present a regional and seasonal climatology of SHADOZ ozone profiles in the troposphere and tropical tropopause layer (TTL) based on measurements taken during the first five years of Aura, 2005-2009, when new stations joined the network at Hanoi, Vietnam; Hilo, Hawaii; Alajuela Heredia, Costa Rica; Cotonou, Benin. In all, 15 stations operated during that period. A west-to-east progression of decreasing convective influence and increasing pollution leads to distinct tropospheric ozone profiles in three regions: (1) western Pacific eastern Indian Ocean; (2) equatorial Americas (San Cristobal, Alajuela, Paramaribo); (3) Atlantic and Africa. Comparisons in total ozone column from soundings, the Ozone Monitoring Instrument (OMI, on Aura, 2004-) satellite and ground-based instrumentation are presented. Most stations show better agreement with OMI than they did for EPTOMS comparisons (1998-2004; Earth-ProbeTotal Ozone Mapping Spectrometer), partly due to a revised above-burst ozone climatology. Possible station biases in the stratospheric segment of the ozone measurement noted in the first 7 years of SHADOZ ozone profiles are re-examined. High stratospheric bias observed during the TOMS period appears to persist at one station. Comparisons of SHADOZ tropospheric ozone and the daily Trajectory-enhanced Tropospheric Ozone Residual (TTOR) product (based on OMIMLS) show that the satellite-derived column amount averages 25 low. Correlations between TTOR and the SHADOZ sondes are quite good (typical r2 0.5-0.8), however, which may account for why some published residual-based OMI products capture tropospheric interannual variability fairly realistically. On the other hand, no clear explanations emerge for why TTOR-sonde discrepancies vary over a wide range at most SHADOZ sites.

  7. High average power pockels cell

    DOEpatents

    Daly, Thomas P.

    1991-01-01

    A high average power pockels cell is disclosed which reduces the effect of thermally induced strains in high average power laser technology. The pockels cell includes an elongated, substantially rectangular crystalline structure formed from a KDP-type material to eliminate shear strains. The X- and Y-axes are oriented substantially perpendicular to the edges of the crystal cross-section and to the C-axis direction of propagation to eliminate shear strains.

  8. Total ozone changes in the 1987 Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Krueger, Arlin J.; Schoeberl, Mark R.; Doiron, Scott D.; Sechrist, Frank; Galimore, Reginald

    1988-01-01

    The development of the Antarctic ozone minimum was observed in 1987 with the Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) instrument. In the first half of August the near-polar (60 and 70 deg S) ozone levels were similar to those of recent years. By September, however, the ozone at 70 and 80 deg S was clearly lower than any previous year including 1985, the prior record low year. The levels continued to decrease throughout September until October 5 when a new record low of 109 DU was established at a point near the South Pole. This value is 29 DU less than the lowest observed in 1985 and 48 DU less than the 1986 low. The zonal mean total ozone at 60 deg S remained constant throughout the time of ozone hole formation. The ozone decline was punctuated by local minima formed away from the polar night boundary at about 75 deg S. The first of these, on August 15 to 17, formed just east of the Palmer Peninsula and appears to be a mountain wave. The second major minimum formed on September 5 to 7 again downwind of the Palmer Peninsula. This event was larger in scale than the August minimum and initiated the decline of ozone across the polar region. The 1987 ozone hole was nearly circular and pole centered for its entire life. In previous years the hole was perturbed by intrusions of the circumpolar maximum into the polar regions, thus causing the hole to be elliptical. The 1987 hole also remained in place until the end of November, a few days longer than in 1985, and this persistence resulted in the latest time for recovery to normal values yet observed.

  9. Is the Ozone Hole over Your Classroom?

    ERIC Educational Resources Information Center

    Cordero, Eugene C.

    2002-01-01

    Reports on a survey of first year university science students regarding their understanding of the ozone layer, ozone depletion, and the effect of ozone depletion on Australia. Suggests that better teaching resources for environmental issues such as ozone depletion and global warming are needed before improvements in student understanding can be…

  10. Atmospheric ozone and man-made pollution.

    PubMed

    Fabian, P

    1976-06-01

    Atmospheric photochemistry and transport processes, related to the ozone layer, are discussed. Natural or man-made changes of the biosphere, variations of radiation, or general circulation as well as anthropogenic release of ozone-destroying catalysts are likely to alter the earth's ozone shield. The possible effects of ozone depletion caused by supersonic aircraft, nuclear weapons, nitrogen fertilizers, and chlorofluoromethanes are discussed.

  11. Elevation of susceptibility to ozone-induced acute tracheobronchial injury in transgenic mice deficient in Clara cell secretory protein

    SciTech Connect

    Plopper, C.G. . E-mail: cgplopper@ucdavis.edu; Mango, G.W.; Hatch, G.E.; Wong, V.J.; Toskala, E.; Reynolds, S.D.; Tarkington, B.K.; Stripp, B.R.

    2006-05-15

    Increases in Clara cell abundance or cellular expression of Clara cell secretory protein (CCSP) may cause increased tolerance of the lung to acute oxidant injury by repeated exposure to ozone (O{sub 3}). This study defines how disruption of the gene for CCSP synthesis affects the susceptibility of tracheobronchial epithelium to acute oxidant injury. Mice homozygous for a null allele of the CCSP gene (CCSP-/-) and wild type (CCSP+/+) littermates were exposed to ozone (0.2 ppm, 8 h; 1 ppm, 8 h) or filtered air. Injury was evaluated by light and scanning electron microscopy, and the abundance of necrotic, ciliated, and nonciliated cells was estimated by morphometry. Proximal and midlevel intrapulmonary airways and terminal bronchioles were evaluated. There was no difference in airway epithelial composition between CCSP+/+ and CCSP-/- mice exposed to filtered air, and exposure to 0.2 ppm ozone caused little injury to the epithelium of both CCSP+/+ and CCSP-/- mice. After exposure to 1.0 ppm ozone, CCSP-/- mice suffered from a greater degree of epithelial injury throughout the airways compared to CCSP+/+ mice. CCSP-/- mice had both ciliated and nonciliated cell injury. Furthermore, lack of CCSP was associated with a shift in airway injury to include proximal airway generations. Therefore, we conclude that CCSP modulates the susceptibility of the epithelium to oxidant-induced injury. Whether this is due to the presence of CCSP on the acellular lining layer surface and/or its intracellular distribution in the secretory cell population needs to be defined.

  12. Elevation of susceptibility to ozone-induced acute tracheobronchial injury in transgenic mice deficient in Clara cell secretory protein.

    PubMed

    Plopper, C G; Mango, G W; Hatch, G E; Wong, V J; Toskala, E; Reynolds, S D; Tarkington, B K; Stripp, B R

    2006-05-15

    Increases in Clara cell abundance or cellular expression of Clara cell secretory protein (CCSP) may cause increased tolerance of the lung to acute oxidant injury by repeated exposure to ozone (O3). This study defines how disruption of the gene for CCSP synthesis affects the susceptibility of tracheobronchial epithelium to acute oxidant injury. Mice homozygous for a null allele of the CCSP gene (CCSP-/-) and wild type (CCSP+/+) littermates were exposed to ozone (0.2 ppm, 8 h; 1 ppm, 8 h) or filtered air. Injury was evaluated by light and scanning electron microscopy, and the abundance of necrotic, ciliated, and nonciliated cells was estimated by morphometry. Proximal and midlevel intrapulmonary airways and terminal bronchioles were evaluated. There was no difference in airway epithelial composition between CCSP+/+ and CCSP-/- mice exposed to filtered air, and exposure to 0.2 ppm ozone caused little injury to the epithelium of both CCSP+/+ and CCSP-/- mice. After exposure to 1.0 ppm ozone, CCSP-/- mice suffered from a greater degree of epithelial injury throughout the airways compared to CCSP+/+ mice. CCSP-/- mice had both ciliated and nonciliated cell injury. Furthermore, lack of CCSP was associated with a shift in airway injury to include proximal airway generations. Therefore, we conclude that CCSP modulates the susceptibility of the epithelium to oxidant-induced injury. Whether this is due to the presence of CCSP on the acellular lining layer surface and/or its intracellular distribution in the secretory cell population needs to be defined.

  13. Corona discharge influences ozone concentrations near rats.

    PubMed

    Goheen, Steven C; Gaither, Kari; Anantatmula, Shantha M; Mong, Gary M; Sasser, Lyle B; Lessor, Delbert

    2004-02-01

    Ozone can be produced by corona discharge either in dry air or when one electrode is submerged in water. Since ozone is toxic, we examined whether ozone production by corona near laboratory animals could reach levels of concern. Male rats were exposed to a corona discharge and the concentration of ozone produced was measured. The resulting concentration of ozone ranged from ambient levels to 250 ppb when animals were located 1 cm from a 10 kV source. Similar ozone concentrations were observed when a grounded water source was present. Possible explanations for, as well as concerns regarding, ozone production under these conditions are discussed. PMID:14735560

  14. A statistical modeling framework for projecting future ambient ozone and its health impact due to climate change

    NASA Astrophysics Data System (ADS)

    Chang, Howard H.; Hao, Hua; Sarnat, Stefanie Ebelt

    2014-06-01

    The adverse health effects of ambient ozone are well established. Given the high sensitivity of ambient ozone concentrations to meteorological conditions, the impacts of future climate change on ozone concentrations and its associated health effects are of concern. We describe a statistical modeling framework for projecting future ozone levels and its health impacts under a changing climate. This is motivated by the continual effort to evaluate projection uncertainties to inform public health risk assessment. The proposed approach was applied to the 20-county Atlanta metropolitan area using regional climate model (RCM) simulations from the North American Regional Climate Change Assessment Program. Future ozone levels and ozone-related excesses in asthma emergency department (ED) visits were examined for the period 2041-2070. The computationally efficient approach allowed us to consider 8 sets of climate model outputs based on different combinations of 4 RCMs and 4 general circulation models. Compared to the historical period of 1999-2004, we found consistent projections across climate models of an average 11.5% higher ozone levels (range: 4.8%, 16.2%), and an average 8.3% (range: -7%-24%) higher number of ozone exceedance days. Assuming no change in the at-risk population, this corresponds to excess ozone-related ED visits ranging from 267 to 466 visits per year. Health impact projection uncertainty was driven predominantly by uncertainty in the health effect association and climate model variability. Calibrating climate simulations with historical observations reduced differences in projections across climate models.

  15. A Statistical Modeling Framework for Projecting Future Ambient Ozone and its Health Impact due to Climate Change.

    PubMed

    Chang, Howard H; Hao, Hua; Sarnat, Stefanie Ebelt

    2014-06-01

    The adverse health effects of ambient ozone are well established. Given the high sensitivity of ambient ozone concentrations to meteorological conditions, the impacts of future climate change on ozone concentrations and its associated health effects are of concern. We describe a statistical modeling framework for projecting future ozone levels and its health impacts under a changing climate. This is motivated by the continual effort to evaluate projection uncertainties to inform public health risk assessment. The proposed approach was applied to the 20-county Atlanta metropolitan area using regional climate model (RCM) simulations from the North American Regional Climate Change Assessment Program. Future ozone levels and ozone-related excesses in asthma emergency department (ED) visits were examined for the period 2041-2070. The computationally efficient approach allowed us to consider 8 sets of climate model outputs based on different combinations of 4 RCMs and 4 general circulation models. Compared to the historical period of 1999-2004, we found consistent projections across climate models of an average 11.5% higher ozone levels (range: 4.8%, 16.2%), and an average 8.3% (range: -7% to 24%) higher number of ozone exceedance days. Assuming no change in the at-risk population, this corresponds to excess ozone-related ED visits ranging from 267 to 466 visits per year. Health impact projection uncertainty was driven predominantly by uncertainty in the health effect association and climate model variability. Calibrating climate simulations with historical observations reduced differences in projections across climate models.

  16. Total ozone column distribution over peninsular Malaysia from scanning imaging absorption spectrometer for atmospheric cartography (SCIAMACHY)

    NASA Astrophysics Data System (ADS)

    Tan, K. C.; Lim, H. S.; MatJafri, M. Z.

    2012-10-01

    Increasing of atmospheric ozone concentrations have received great attention around the whole because of its characteristic, in order to degrade air quality and brings hazard to human health and ecosystems. Ozone, one of the most pollutants source and brings a variety of adverse effects on plant life and human being. Continuous monitoring on ozone concentrations at atmosphere provide information and precautions for the high ozone level, which we need to be established. Satellite observation of ozone has been identified that it can provide the precise and accurate data globally, which sensitive to the small regional biases. We present measurements from Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) included on the European environmental satellite ENVISAT, launched on 1st of March 2002. Main objective of this study is to examine the ozone distribution over Peninsular Malaysia using SCIAMACHY level-2 of total ozone column WFMD version 1.0 with spatial resolution 1° x 1.25°. Maps of time averaged (yearly, tri-monthly) ozone was generated and analyzed over Peninsular Malaysia for the year 2003 using PCI Geomatica 10.3 image processing software. It was retrieved using the interpolation technique. The concentration changes within boundary layer at all altitude levels are equally sensitive through the SCIAMACHY nearinfrared nadir observations. Hence, we can make observation of ozone at surface source region. The results successfully identify the area with highest and lowest concentration of ozone at Peninsular Malaysia using SCIAMACHY data. Therefore, the study is suitable to examine the distribution of ozone at tropical region.

  17. The potential near-source ozone impacts of upstream oil and gas industry emissions.

    PubMed

    Olaguer, Eduardo P

    2012-08-01

    Increased drilling in urban areas overlying shale formations and its potential impact on human health through decreased air quality make it important to estimate the contribution of oil and gas activities to photochemical smog. Flares and compressor engines used in natural gas operations, for example, are large sources not only of NOx but also offormaldehyde, a hazardous air pollutant and powerful ozone precursor We used a neighborhood scale (200 m horizontal resolution) three-dimensional (3D) air dispersion model with an appropriate chemical mechanism to simulate ozone formation in the vicinity ofa hypothetical natural gas processing facility, based on accepted estimates of both regular and nonroutine emissions. The model predicts that, under average midday conditions in June, regular emissions mostly associated with compressor engines may increase ambient ozone in the Barnett Shale by more than 3 ppb beginning at about 2 km downwind of the facility, assuming there are no other major sources of ozone precursors. Flare volumes of 100,000 cubic meters per hour ofnatural gas over a period of 2 hr can also add over 3 ppb to peak 1-hr ozone somewhatfurther (>8 km) downwind, once dilution overcomes ozone titration and inhibition by large flare emissions of NOx. The additional peak ozone from the hypothetical flare can briefly exceed 10 ppb about 16 km downwind. The enhancements of ambient ozone predicted by the model are significant, given that ozone control strategy widths are of the order of a few parts per billion. Degrading the horizontal resolution of the model to 1 km spuriously enhances the simulated ozone increases by reducing the effectiveness of ozone inhibition and titration due to artificial plume dilution. PMID:22916444

  18. A new ENSO index derived from satellite measurements of column ozone

    NASA Astrophysics Data System (ADS)

    Ziemke, J. R.; Chandra, S.; Oman, L. D.; Bhartia, P. K.

    2010-02-01

    Column Ozone measured in tropical latitudes from Nimbus 7 TOMS, Earth Probe TOMS, NOAA SBUV, and Aura OMI satellite instruments are used to derive an El Niño-Southern Oscillation (ENSO) index. This index, which covers a time period from 1979 to the present, is defined as the Ozone ENSO Index (OEI) and is the first developed from atmospheric trace gas measurements. Using a data mining technique with existing ENSO indices of surface pressure and sea-surface temperature, the OEI is constructed by first averaging monthly mean column ozone over two broad regions in the western and eastern Pacific and taking their difference. This differencing yields a self-calibrating ENSO index which is independent of individual instrument calibration offsets and drifts in measurements over the long record. The combined Aura OMI and MLS ozone data confirm that zonal variability in total column ozone in the tropics caused by ENSO events lies almost entirely in the troposphere. As a result, the OEI can be derived directly from total column ozone instead of tropospheric column ozone. For clear-sky ozone measurements a +1 K change in Nino 3.4 index corresponds to +2.9 DU (Dobson Unit) change in the OEI, while a +1 hPa change in SOI coincides with a -1.7 DU change in the OEI. For ozone measurements under all cloud conditions these numbers are +2.4 DU and -1.4 DU, respectively. As an ENSO index based upon ozone, it is potentially useful in evaluating climate models predicting long term changes in ozone and other trace gases.

  19. Unprecedented Arctic ozone loss in 2011.

    PubMed

    Manney, Gloria L; Santee, Michelle L; Rex, Markus; Livesey, Nathaniel J; Pitts, Michael C; Veefkind, Pepijn; Nash, Eric R; Wohltmann, Ingo; Lehmann, Ralph; Froidevaux, Lucien; Poole, Lamont R; Schoeberl, Mark R; Haffner, David P; Davies, Jonathan; Dorokhov, Valery; Gernandt, Hartwig; Johnson, Bryan; Kivi, Rigel; Kyrö, Esko; Larsen, Niels; Levelt, Pieternel F; Makshtas, Alexander; McElroy, C Thomas; Nakajima, Hideaki; Parrondo, Maria Concepción; Tarasick, David W; von der Gathen, Peter; Walker, Kaley A; Zinoviev, Nikita S

    2011-10-27

    Chemical ozone destruction occurs over both polar regions in local winter-spring. In the Antarctic, essentially complete removal of lower-stratospheric ozone currently results in an ozone hole every year, whereas in the Arctic, ozone loss is highly variable and has until now been much more limited. Here we demonstrate that chemical ozone destruction over the Arctic in early 2011 was--for the first time in the observational record--comparable to that in the Antarctic ozone hole. Unusually long-lasting cold conditions in the Arctic lower stratosphere led to persistent enhancement in ozone-destroying forms of chlorine and to unprecedented ozone loss, which exceeded 80 per cent over 18-20 kilometres altitude. Our results show that Arctic ozone holes are possible even with temperatures much milder than those in the Antarctic. We cannot at present predict when such severe Arctic ozone depletion may be matched or exceeded. PMID:21964337

  20. Influence of equatorial QBO (quasi-biennial oscillation) and SST (sea-surface temperature) on polar total ozone, and the 1990 Antarctic ozone hole

    SciTech Connect

    Angell, J.K. )

    1990-09-01

    Based on data through 1989, comparisons are made between the variation of total ozone at Resolute, Canada (75{degree}N) and South Pole, and the variation of low-stratospheric temperature at Singapore (reflecting the equatorial QBO) and SST in eastern equatorial Pacific (reflecting the ENSO phenomenon). Total-ozone variations at Resolute have been more closely related to the QBO, whereas the total-ozone variations at South Pole appear to have been almost equally related to QBO and SST. When the average of 50 mb and 30 mb June-July-August (JJA) values of Singapore temperature ({bar T}) increased from one year to the next, the decrease in South Pole springtime total ozone for the same years averaged 21 {plus minus} 14% greater than when {bar T} decreased. When the JJA values of equatorial SST increased from one year to the next, the decrease in South Pole springtime total ozone for the same years averaged 18 {plus minus} 12% greater than when SST decreased. In the 6 cases when JJA values of both Singapore {bar T} and equatorial SST increased from one year to the next, the spring values of South Pole total ozone have decreased, whereas in the 6 cases when both {bar T} and SST decreased from one year to the next, South Pole total ozone has increased. Both Singapore {bar T} and equatorial SST will probably be warmer in JJA of 1990 than they were in JJA of 1989 suggesting, based on these previous relations, an even deeper Antarctic ozone hole in 1990 than in 1989 and ending the biennial variation in depth of the hole of the last 6 years.

  1. Balloon-borne observations of the development and vertical structure of the Antarctic ozone hole in 1986

    NASA Technical Reports Server (NTRS)

    Hofmann, D. J.; Harder, J. W.; Rolf, S. R.; Rosen, J. M.

    1987-01-01

    The vertical distribution of ozone measured at McMurdo Station, Antarctica using balloon-borne sensors on 33 occasions during November 6, 1986 - August 25, 1986 is described. These observations suggest a highly structured cavity confined to the 12-20 km altitude region. In the 17-19 km altitude range, the ozone volume mixing ratio declined from about 2 ppm at the end of August to about 0.5 ppm by mid-October. The average decay in this region can be described as exponential with a half life of about 25 days. While total ozone, as obtained from profile integration, declined only about 35 percent, the integrated ozone between 14 and 18 km declined more than 70 percent. Vertical ozone profiles in the vortex revealed unusual structure with major features from 1 to 5 km thick which had suffered ozone depletions as great as 90 percent.

  2. Influence of wildfires on the variability and trend of ozone concentrations in the U.S. Intermountain West

    NASA Astrophysics Data System (ADS)

    Lu, Xiao; Zhang, Lin; Zhao, Yuanhong; Yue, Xu

    2016-04-01

    Wildfires are important sources of ozone by emitting large amounts of NOx and NMVOC, main ozone precursors at both global and regional scales. Their influences on ozone in the U.S. Intermountain West have recently received much interest because surface ozone concentrations over that region showed an increasing trend in the past two decades likely due to increasing wildfire emissions in a warming climate. Here we use the Lagrangian particle dispersion model (FLEXPART) as well as the GEOS-Chem chemical transport model to estimate wildfires' contribution on summer (June, July and August; JJA) ozone concentration variations, trends, and extremely high ozone events over the US Intermountain West for the past 22 years (1989-2010). We combine the resident time estimated from the FLEXPART 5-day backward trajectories and a high-resolution fire inventory to define a fire index representing the impact of wildfires on ozone concentration at a particular site for each day of summers 1989-2010. Over 26,000 FLEXPART back-trajectories are conducted for the whole time period and for 13 CASTNet surface monitoring sites. We build a stepwise multiple linear regression (SMLR) model of daily ozone concentrations using fire index and other meteorological variables for each site. The SMLR models explain 53% of the ozone variations (ranging from 12% to 68% for each site). We show that ozone produced from wildfires (calculated from SMLR model) are of high variability at daily scale (ranging from 0.1 ppbv to 20.7 ppbv), but are averaged to lower values of about 0.25-3.5 ppbv for summer mean. We estimate that wildfires magnify inter-annual variations of the regional mean summer ozone for about 32%, compared to the result with wildfires impact excluded from the SMLR model. Wildfire ozone enhancements increase at a rate of 0.04 ppbv per year, accouting for about 20% of the regional summer ozone trend during 1989-2010. Removing wildfires' impact would reduce 35% (46%) of the high-ozone days with

  3. 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.

  4. 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.

  5. 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.

  6. Photochemical roles of rapid economic growth and potential abatement strategies on tropospheric ozone over South and East Asia in 2030

    NASA Astrophysics Data System (ADS)

    Chatani, S.; Amann, M.; Goel, A.; Hao, J.; Klimont, Z.; Kumar, A.; Mishra, A.; Sharma, S.; Wang, S. X.; Wang, Y. X.; Zhao, B.

    2014-09-01

    A regional air quality simulation framework including the Weather Research and Forecasting modeling system (WRF), the Community Multi-scale Air Quality modeling system (CMAQ), and precursor emissions to simulate tropospheric ozone over South and East Asia is introduced. Concentrations of tropospheric ozone and related species simulated by the framework are validated by comparing with observation data of surface monitoring, ozonesondes, and satellites obtained in 2010. The simulation demonstrates acceptable performance on tropospheric ozone over South and East Asia at regional scale. Future energy consumption, carbon dioxide (CO2), nitrogen oxides (NOx), and volatile organic compound (VOC) emissions in 2030 under three future scenarios are estimated. One of the scenarios assumes a business-as-usual (BAU) pathway, and other two scenarios consider implementation of additional energy and environmental strategies to reduce energy consumption, CO2, NOx, and VOC emissions in China and India. Future surface ozone under these three scenarios is predicted by the simulation. The simulation indicates future surface ozone significantly increases around India for a whole year and around northeastern China in summer. NOx is a main driver on significant seasonal increase of surface ozone, whereas VOC as well as increasing background ozone and methane is also an important factor on annual average of surface ozone in East Asia. Warmer weather around India is also preferable for significant increase of surface ozone. Additional energy and environmental strategies assumed in future scenarios are expected to be effective to reduce future surface ozone over South and East Asia.

  7. Integrated assessment modeling of atmospheric pollutants in the Southern Appalachian Mountains. Part I: hourly and seasonal ozone.

    PubMed

    Boylan, James W; Odman, Mehmet T; Wilkinson, James G; Russell, Armistead G; Doty, Kevin G; Norris, William B; McNider, Richard T

    2005-07-01

    Recently, a comprehensive air quality modeling system was developed as part of the Southern Appalachians Mountains Initiative (SAMI) with the ability to simulate meteorology, emissions, ozone, size- and composition-resolved particulate matter, and pollutant deposition fluxes. As part of SAMI, the RAMS/EMS-95/URM-1ATM modeling system was used to evaluate potential emission control strategies to reduce atmospheric pollutant levels at Class I areas located in the Southern Appalachians Mountains. This article discusses the details of the ozone model performance and the methodology that was used to scale discrete episodic pollutant levels to seasonal and annual averages. The daily mean normalized bias and error for 1-hr and 8-hr ozone were within U.S. Environment Protection Agency guidance criteria for urban-scale modeling. The model typically showed a systematic overestimation for low ozone levels and an underestimation for high levels. Because SAMI was primarily interested in simulating the growing season ozone levels in Class I areas, daily and seasonal cumulative ozone exposure, as characterized by the W126 index, were also evaluated. The daily ozone W126 performance was not as good as the hourly ozone performance; however, the seasonal ozone W126 scaled up from daily values was within 17% of the observations at two typical Class I areas of the SAMI region. The overall ozone performance of the model was deemed acceptable for the purposes of SAMI's assessment. PMID:16111143

  8. Northern middle-latitude ozone profile features and trends observed by SBUV and Umkehr, 1979-1990

    NASA Technical Reports Server (NTRS)

    Deluisi, J. J.; Mateer, C. L.; Theisen, D.; Bhartia, P. K.; Longenecker, D.; Chu, B.

    1994-01-01

    A comparison of Umkehr ozone profile data with the reprocessed solar backscatter ultraviolet (SBUV) ozone data in the northern middle-latitude region, 30 deg to 50 deg N, is reported. Although significant biases exist between the two types of observations, the long-term variations and least squares linear regression trends agree remarkably well over the comparison period of 1979 to 1990. The ozone trend in the upper stratosphere is of the order of -0.9%/yr. Near 25 km, little if any trend appears, but a larger negative trend is seen in the lower stratosphere near 15 km. Comparisons show that the average annual ozone cycles in the profiles also agree well. The upper stratospheric ozone results are consistent with photochemical model predictions of ozone depletion near 40 km that are due to the release of anthropogenically produced chlorofluorocarbons. The lower stratospheric ozone trend results are in reasonable agreement with published ozonesonde data trends. It is shown that the ozone trends in the lower stratospheric layers impact significantly on the total ozone trend of the order of -0.47%/yr. The good agreement now seen between the two types of observations suggest that the combined ground-based and satellite approach could provide a valuable database for long-term monitoring of stratospheric ozone for trends and extraordinary variations.

  9. Brewer Umkehr ozone profile retrievals

    NASA Astrophysics Data System (ADS)

    Petropavlovskikh, I. V.; Disterhoft, P.; Lantz, K. O.; Bhartia, P. K.; McPeters, R. D.; Flynn, L. E.; Oltmans, S. J.; Johnson, B. J.; Stanek, M.

    2011-12-01

    The Dobson Umkehr network has been a key data set for stratospheric ozone trend calculations (WMO Ozone assessments) and has earned its place as a benchmark network for stratospheric ozone profile observations. The Umkehr data has also been used to provide a long-term reference to the merging of the satellite ozone records (MOD), estimate the seasonal influence of an 11-year solar signal in the vertical distribution of stratospheric ozone, and to assess the ability of several remote and in-situ sensing systems in capturing ozone variability. It was found that Dobson Umkehr measurement errors were often comparable to errors derived for satellite and ozone-sounding methods. The Umkehr measurements are also available from the Brewer spectrophotometers [McElroy et al., 1995]. In 2005, the Dobson Umkehr algorithm (UMK04) was modified to retrieve ozone profile data from Brewer Umkehr measurements taken at two spectral channels [Petropavlovskikh et al, 2011]. The PC version of the Brewer algorithm was developed by M. Stanek (IOC, Canada and Czech Republic Meteorological Institute) in close collaboration with I. Petropavlovskikh. It was implemented at the NEUBrew network for operational processing of Umkehr data retrieved daily for all operational sites. The most recently developed Brewer ozone retrieval algorithm (MSBU) utilizes measurements that are currently available from the operational Brewer instruments. Umkehr measurements at multiple wavelength channels (similar to the satellite BUV method) and significantly reduced range of solar zenith angle are used for the twice a day operational ozone profile retrievals. Intercomparisons against ozone climatology, sounding, satellite overpasses and Dobson ozone datasets for NOASA/Goddard, Boulder, CO and MLO, HI sites are presented in this paper. The MSBU algorithm reduces noise in the intra-annual variability of the Brewer retrieved ozone as compared to the single pair ozone retrieval. Tropospheric ozone retrievals also

  10. Total ozone trend over Cairo

    NASA Technical Reports Server (NTRS)

    Hassan, G. K. Y.

    1994-01-01

    A world wide interest in protecting ozone layer against manmade effects is now increasing. Assessment of the ozone depletion due to these activities depends on how successfully we can separate the natural variabilities from the data. The monthly mean values of total ozone over Cairo (30 05N) for the period 1968-1988, have been analyzed using the power spectral analysis technique. The technique used in this analysis does not depend on a pre-understanding of the natural fluctuations in the ozone data. The method depends on increasing the resolution of the spectral peaks in order to obtain the more accurate sinusoidal fluctuations with wavelength equal to or less than record length. Also it handles the possible sinusoidal fluctuations with wavelength equal to or less than record length. The results show that it is possible to detect some of the well known national fluctuations in the ozone record such as annual, semiannual, quasi-biennial and quasi-quadrennial oscillations. After separating the natural fluctuations from the ozone record, the trend analysis of total ozone over Cairo showed that a decrease of about -1.2% per decade has occurred since 1979.

  11. [Analysis on concentration variety characteristics of atmospheric ozone under the boundary layer in Beijing].

    PubMed

    Zong, Xue-Mei; Wang, Geng-Chen; Chen, Hong-Bin; Wang, Pu-Cai; Xuan, Yue-Jian

    2007-11-01

    Based on the atmospheric ozone sounding data, the average monthly and seasonal variety principles of atmospheric ozone concentration during six years are analyzed under the boundary layer in Beijing. The results show that the monthly variation of atmospheric ozone are obvious that the minimum values appear in January from less than 10 x 10(-9) on ground to less than 50 x 10(-9) on upper layer (2 km), but the maximum values appear in June from 85 x 10(-9) on ground to more than 90 x 10(-9) on upper layer. The seasonal variation is also clear that the least atmospheric ozone concentration is in winter and the most is in summer, but variety from ground to upper layer is largest in winter and least in summer. According to the type of outline, the outline of ozone concentration is composite of three types which are winter type, summer type and spring-autumn type. The monthly ozone concentration in different heights is quite different. After analyzing the relationship between ozone concentration and meteorological factors, such as temperature and humidity, we find ozone concentration on ground is linear with temperature and the correlation coefficient is more than 85 percent.

  12. Impact of future nitrous oxide and carbon dioxide emissions on the stratospheric ozone layer

    NASA Astrophysics Data System (ADS)

    Stolarski, Richard S.; Douglass, Anne R.; Oman, Luke D.; Waugh, Darryn W.

    2015-03-01

    The atmospheric levels of human-produced chlorocarbons and bromocarbons are projected to make only small contributions to ozone depletion by 2100. Increases in carbon dioxide (CO2) and nitrous oxide (N2O) will become increasingly important in determining the future of the ozone layer. N2O increases lead to increased production of nitrogen oxides (NOx), contributing to ozone depletion. CO2 increases cool the stratosphere and affect ozone levels in several ways. Cooling decreases the rate of many photochemical reactions, thus slowing ozone loss rates. Cooling also increases the chemical destruction of nitrogen oxides, thereby moderating the effect of increased N2O on ozone depletion. The stratospheric ozone level projected for the end of this century therefore depends on future emissions of both CO2 and N2O. We use a two-dimensional chemical transport model to explore a wide range of values for the boundary conditions for CO2 and N2O, and find that all of the current scenarios for growth of greenhouse gases project the global average ozone to be larger in 2100 than in 1960.

  13. Bactericidal activity, eggshell conductance, and hatchability effects of ozone versus formaldehyde disinfection

    SciTech Connect

    Whistler, P.E.; Sheldon, B.W. )

    1989-08-01

    Ozone and formaldehyde were evaluated as disinfectants in a prototype laboratory setter against microorganisms that are naturally present on fertile, freshly laid, broiler hatching eggs. Significantly lower microbial counts of over 2.5 log10 (P less than .05) were observed for water-misted and ozonated (2.83% by weight) eggs or formaldehyde-fumigated (triple strength) eggs than for control and water-misted eggs. Eggshell conductance studies as measured by egg moisture losses in a desiccator showed no significant differences (P greater than .05) among untreated, water misted, ozonated (3.06% by weight) with water mist, or formaldehyde (triple strength)-fumigated eggs. Hatchability was significantly reduced (26.5 to 37.5%) following ozonation (3.03% ozone by weight, 2 h) in comparison with effects of no treatment or water misting. Misting with ozonation was equally as effective as formaldehyde fumigation in reducing microbial counts. However, ozone treatment at the concentrations tested significantly reduced hatchability when compared with results of either no treatment, water misting, or an average hatchability figure for formaldehyde fumigation. These findings indicate that ozone is a good disinfectant yet may adversely affect embryo development when given in the gaseous form.

  14. Decline and recovery of total column ozone using a multimodel time series analysis

    NASA Astrophysics Data System (ADS)

    Austin, John; Scinocca, J.; Plummer, D.; Oman, L.; Waugh, D.; Akiyoshi, H.; Bekki, S.; Braesicke, P.; Butchart, N.; Chipperfield, M.; Cugnet, D.; Dameris, M.; Dhomse, S.; Eyring, V.; Frith, S.; Garcia, R. R.; Garny, H.; Gettelman, A.; Hardiman, S. C.; Kinnison, D.; Lamarque, J. F.; Mancini, E.; Marchand, M.; Michou, M.; Morgenstern, O.; Nakamura, T.; Pawson, S.; Pitari, G.; Pyle, J.; Rozanov, E.; Shepherd, T. G.; Shibata, K.; TeyssèDre, H.; Wilson, R. J.; Yamashita, Y.

    2010-01-01

    Simulations of 15 coupled chemistry climate models, for the period 1960-2100, are presented. The models include a detailed stratosphere, as well as including a realistic representation of the tropospheric climate. The simulations assume a consistent set of changing greenhouse gas concentrations, as well as temporally varying chlorofluorocarbon concentrations in accordance with observations for the past and expectations for the future. The ozone results are analyzed using a nonparametric additive statistical model. Comparisons are made with observations for the recent past, and the recovery of ozone, indicated by a return to 1960 and 1980 values, is investigated as a function of latitude. Although chlorine amounts are simulated to return to 1980 values by about 2050, with only weak latitudinal variations, column ozone amounts recover at different rates due to the influence of greenhouse gas changes. In the tropics, simulated peak ozone amounts occur by about 2050 and thereafter total ozone column declines. Consequently, simulated ozone does not recover to values which existed prior to the early 1980s. The results also show a distinct hemispheric asymmetry, with recovery to 1980 values in the Northern Hemisphere extratropics ahead of the chlorine return by about 20 years. In the Southern Hemisphere midlatitudes, ozone is simulated to return to 1980 levels only 10 years ahead of chlorine. In the Antarctic, annually averaged ozone recovers at about the same rate as chlorine in high latitudes and hence does not return to 1960s values until the last decade of the simulations.

  15. 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.

  16. Correlative studies of satellite ozone sensor measurements

    NASA Technical Reports Server (NTRS)

    Lovill, J. E.; Ellis, J. S.

    1983-01-01

    Comparisons are made between total ozone measurements made by four satellite ozone sensors (TOMS, SBUV, TOVS and MFR). The comparisons were made during July 1979 when all sensors were operating simultaneously. The TOMS and SBUV sensors were observed to measure less total ozone than the MFR sensor, 10 and 15 Dobson units (DU) respectively. The MFR and TOMS sensors measured less ozone than the TOVS sensor, 19 and 28 DU, respectively. Latitudinal variability of the total ozone comparisons is discussed.

  17. Improved western U.S. background ozone estimates via constraining nonlocal and local source contributions using Aura TES and OMI observations

    NASA Astrophysics Data System (ADS)

    Huang, Min; Bowman, Kevin W.; Carmichael, Gregory R.; Lee, Meemong; Chai, Tianfeng; Spak, Scott N.; Henze, Daven K.; Darmenov, Anton S.; Silva, Arlindo M.

    2015-04-01

    Western U.S. near-surface ozone (O3) concentrations are sensitive to transported background O3 from the eastern Pacific free troposphere, as well as U.S. anthropogenic and natural emissions. The current 75 ppbv U.S. O3 primary standard may be lowered soon, hence accurately estimating O3 source contributions, especially background O3 in this region has growing policy-relevant significance. In this study, we improve the modeled total and background O3, via repartitioning and redistributing the contributions from nonlocal and local anthropogenic/wildfires sources in a multi-scale satellite data assimilation system containing global Goddard Earth Observing System-Chemistry model (GEOS-Chem) and regional Sulfur Transport and dEposition Model (STEM). Focusing on NASA's ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) field campaign period in June-July 2008, we first demonstrate that the negative biases in GEOS-Chem free simulation in the eastern Pacific at 400-900 hPa are reduced via assimilating Aura-Tropospheric Emission Spectrometer (TES) O3 profiles. Using the TES-constrained boundary conditions, we then assimilated into STEM the tropospheric nitrogen dioxide (NO2) columns from Aura-Ozone Monitoring Instrument to indicate U.S. nitrogen oxides (NOx = NO2 + NO) emissions at 12 × 12 km2 grid scale. Improved model skills are indicated from cross validation against independent ARCTAS measurements. Leveraging Aura observations, we show anomalously high wildfire NOx emissions in this summer in Northern California and the Central Valley while lower anthropogenic emissions in multiple urban areas than those representing the year of 2005. We found strong spatial variability of the daily maximum 8 h average background O3 and its contribution to the modeled total O3, with the mean value of ~48 ppbv (~77% of the total).

  18. Dielectric relaxation of a-cyclodextrin-polyiodide complexes (a-cyclodextrin)2·BaI2·I2·8H2O and (a-cyclodextrin)2·KI3·I2·8H2O

    NASA Astrophysics Data System (ADS)

    Papaioannou, John C.; Ghikas, Thanos C.

    The frequency and temperature dependence of the real (ɛ') and imaginary (ɛ') parts of the dielectric constant of the polycrystalline complexes (α-CD)2·BaI2·I2·8H2O and (α-CD)2·KI3·I2·8H2O (α-CD = α-cyclodetrin) have been investigated over the frequency and temperature ranges 0-100 kHz and 120-300 K, respectively. The temperature dependences of ɛ', ɛ' and the phase shift φ show two steps, two peaks and two minima, respectively, revealing the existence of two kinds of water molecule, the tightly bound and the easily movable water molecules, in both complexes. The first peak of ɛ'(T) or the first minimum of φ(T) presents the transformation of flip-flop hydrogen bonds to the normal state. The second ɛ' (T) peak or φ(T) minimum corresponds to the easily movable water molecules or to a partial transformation of tightly bound to easily movable water molecules. For T > 270 K both samples show semiconductive behaviour with energy gaps of 1.84 eV for the (α-CD)2·BaI2·I2·8H2O complex and 1.36 eV for the (α-CD)2·KI3·I2·8H2O complex. The conductivity at room temperature decreases in the order: (α-CD)2·BaI2·I2·8H2O > (α-CD)2·LiI3·I2·8H2O > (α-CD)2·KI3·I2·8H2O > (αCD)2·Cd0.5·I5·26H2O. The relaxation time varies in a Λ-like curve (from 120 to 250 K) and rises rapidly for temperatures greater than 250 K, indicating the process of ionic movements. The activation energies around the transition temperature 0.98-1.09 kBTtrans for (α-CD)2·BaI2·I2·8H2O and 1.06-1.55 kBTtrans for (α-CD)2·KI3·I2·8H2O reveal the greater stability of the α-K complex against that of the α-Ba complex.

  19. Determining GPS average performance metrics

    NASA Technical Reports Server (NTRS)

    Moore, G. V.

    1995-01-01

    Analytic and semi-analytic methods are used to show that users of the GPS constellation can expect performance variations based on their location. Specifically, performance is shown to be a function of both altitude and latitude. These results stem from the fact that the GPS constellation is itself non-uniform. For example, GPS satellites are over four times as likely to be directly over Tierra del Fuego than over Hawaii or Singapore. Inevitable performance variations due to user location occur for ground, sea, air and space GPS users. These performance variations can be studied in an average relative sense. A semi-analytic tool which symmetrically allocates GPS satellite latitude belt dwell times among longitude points is used to compute average performance metrics. These metrics include average number of GPS vehicles visible, relative average accuracies in the radial, intrack and crosstrack (or radial, north/south, east/west) directions, and relative average PDOP or GDOP. The tool can be quickly changed to incorporate various user antenna obscuration models and various GPS constellation designs. Among other applications, tool results can be used in studies to: predict locations and geometries of best/worst case performance, design GPS constellations, determine optimal user antenna location and understand performance trends among various users.

  20. Vocal attractiveness increases by averaging.

    PubMed

    Bruckert, Laetitia; Bestelmeyer, Patricia; Latinus, Marianne; Rouger, Julien; Charest, Ian; Rousselet, Guillaume A; Kawahara, Hideki; Belin, Pascal

    2010-01-26

    Vocal attractiveness has a profound influence on listeners-a bias known as the "what sounds beautiful is good" vocal attractiveness stereotype [1]-with tangible impact on a voice owner's success at mating, job applications, and/or elections. The prevailing view holds that attractive voices are those that signal desirable attributes in a potential mate [2-4]-e.g., lower pitch in male voices. However, this account does not explain our preferences in more general social contexts in which voices of both genders are evaluated. Here we show that averaging voices via auditory morphing [5] results in more attractive voices, irrespective of the speaker's or listener's gender. Moreover, we show that this phenomenon is largely explained by two independent by-products of averaging: a smoother voice texture (reduced aperiodicities) and a greater similarity in pitch and timbre with the average of all voices (reduced "distance to mean"). These results provide the first evidence for a phenomenon of vocal attractiveness increases by averaging, analogous to a well-established effect of facial averaging [6, 7]. They highlight prototype-based coding [8] as a central feature of voice perception, emphasizing the similarity in the mechanisms of face and voice perception.

  1. Vocal attractiveness increases by averaging.

    PubMed

    Bruckert, Laetitia; Bestelmeyer, Patricia; Latinus, Marianne; Rouger, Julien; Charest, Ian; Rousselet, Guillaume A; Kawahara, Hideki; Belin, Pascal

    2010-01-26

    Vocal attractiveness has a profound influence on listeners-a bias known as the "what sounds beautiful is good" vocal attractiveness stereotype [1]-with tangible impact on a voice owner's success at mating, job applications, and/or elections. The prevailing view holds that attractive voices are those that signal desirable attributes in a potential mate [2-4]-e.g., lower pitch in male voices. However, this account does not explain our preferences in more general social contexts in which voices of both genders are evaluated. Here we show that averaging voices via auditory morphing [5] results in more attractive voices, irrespective of the speaker's or listener's gender. Moreover, we show that this phenomenon is largely explained by two independent by-products of averaging: a smoother voice texture (reduced aperiodicities) and a greater similarity in pitch and timbre with the average of all voices (reduced "distance to mean"). These results provide the first evidence for a phenomenon of vocal attractiveness increases by averaging, analogous to a well-established effect of facial averaging [6, 7]. They highlight prototype-based coding [8] as a central feature of voice perception, emphasizing the similarity in the mechanisms of face and voice perception. PMID:20129047

  2. Ultrafine particles generated from coloring with scented markers in the presence of ozone.

    PubMed

    Fung, C-C D; Shu, S; Zhu, Y

    2014-10-01

    High concentrations of ultrafine particles (UFPs) have been previously reported during school art activities. This is possibly due to secondary organic aerosols (SOAs) formed from reactions between ozone and volatile organic compounds emitted from art products. Four brands of markers, three scented and one unscented, were tested inside a stainless steel chamber at eight different ozone concentrations between 0 and 300 ppb. Out of the 32 tested markers, only the lemon- and orange-scented markers from one brand reacted with ozone to form UFPs. Limonene, pinene, and several other terpenes were identified as ingredients of ink in SOA-forming markers. Coloring with one lemon-scented marker for 1 min without ozone generated on average approximately 26 ± 4 ppb of limonene inside the chamber. At 150 ppb ozone, using one lemon marker for 1 min formed on average 7.7 × 10(10) particles. The particle size distribution indicated an initial mode of 15 nm which grew to 40 nm. At 50 ppb ozone and below, no significant SOA formation occurred. The number of particles formed is moderately correlated with the mass of ink used (R(2)  = 0.68). Based on these data, scented markers are not likely a strong source of SOA under normal indoor ozone levels.

  3. Microphysical Modelling of the 1999-2000 Arctic Winter. 2; Chlorine Activation and Ozone Depletion

    NASA Technical Reports Server (NTRS)

    Drdla, K.; Schoeberl, M. R.; Gore, Warren J. (Technical Monitor)

    2001-01-01

    The effect of a range of assumptions about polar stratospheric clouds (PSCs) on ozone depletion has been assessed using at couple microphysical/photochemical model. The composition of the PSCs was varied (ternary solutions, nitric acid trihydrate, nitric acid dehydrate, or ice), as were parameters that affected the levels of denitrification and dehydration. Ozone depletion was affected by assumptions about PSC freezing because of the variability in resultant nitrification chlorine activation in all scenarios was similar despite the range of assumed PSC compositions. Vortex-average ozone loss exceeded 40% in the lower stratosphere for simulations without nitrification an additional ozone loss of 15-20% was possible in scenarios where vortex-average nitrification reached 60%. Ozone loss intensifies non-linearly with enhanced nitrification in air parcels with 90% nitrification 40% ozone loss in mid-April can be attributed to nitrification alone. However, these effects are sensitive to the stability of the vortex in springtime: nitrification only began to influence ozone depletion in mid-March.

  4. [Treatment of petrochemical secondary effluent by ozone-biological aerated filter].

    PubMed

    Liu, Ming-Guo; Wu, Chang-Yong; Zhou, Yue-Xi; Gao, Zhen; Wang, Pei-Chao; Yang, Qi; Dong, De

    2014-02-01

    The advanced treatment of petrochemical secondary wastewater by ozone- aerated biological filter was carried out in this study. The effect of pH on ozonation and the removal of COD and UV254 by the ozone-aerated biological filter combined process were investigated. In addition, the variation of relative molecular mass distribution of organics and the characteristics of three-dimensional fluorescence spectra of the wastewater were also investigated. The results showed that the suitable operating conditions of the ozonation unit were: ozone dosage 10 mg x L(-1), contact time 4 min and slightly alkaline pH. Ozonation can transfer macromolecular organics into small molecular organics, resulting in a 15% increase in the percentage of the organics with small relative molecular mass (less than 1 000). The biodegradability of the petrochemical secondary effluent was significantly improved by ozonation, making it more suitable for the treatment by aerated biological filter. The removal efficiency of COD and UV254 were 40.8% and 45.8% when the hydraulic retention time was 3 hours and the gas to water ratio was 3:1 for BAF. The average COD of the petrochemical wastewater was 86.5 mg x L(-1) while the average COD of the effluent of the combined process was 49.4 mg x L(-1) when it was operated under optimal conditions.

  5. 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 wi