Spatial and seasonal heterogeneity of atmospheric particles induced reactive oxygen species in urban areas and the role of water-soluble metals.

PubMed

Gali, Nirmal Kumar; Yang, Fenhuan; Jiang, Sabrina Yanan; Chan, Ka Lok; Sun, Li; Ho, Kin-fai; Ning, Zhi

2015-03-01

Adverse health effects are associated with exposure to atmospheric particulate matter (PM), which carry various chemical constituents and induce both exogenous and endogenous oxidative stress. This study investigated the spatial and seasonal variability of PM-induced ROS at four sites with different characteristics in Hong Kong. Cytotoxicity, exogenous and endogenous ROS was determined on a dose and time dependent analysis. Large spatial variation of ROS was observed with fine PM at urban site showing highest ROS levels while coarse PM at traffic site ranks the top. No consistent seasonal difference was observed for ROS levels among all sites. The highly heterogeneous distribution of PM-induced ROS demonstrates the differential capability of PM to produce oxidative stress, and the need to use appropriate metrics as surrogates of exposure instead of PM mass in epidemiologic studies. Several transition metals were found associated with ROS by different degree illustrating the complexity of mechanisms involved. Copyright © 2015 Elsevier Ltd. All rights reserved.

A comparative study of atmospheric corrosion in the Caribbean area

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

Maldonado, L.; Castro, P.; Echeverria, M.

1995-10-01

Atmospheric corrosion is a phenomenon of such a magnitude that has been cause of study in several countries for decades. Nevertheless, in Mexico, it became of recent interest due to new economic factors that have involved the Peninsula of Yucatan too. The Yucatan Peninsula is limited to the North and West by the Gulf of Mexico and to the East by the Caribbean Sea. This is a non industrialized region so that in the past very little importance was given to the atmospheric corrosion damage or to the quantification of the high corrosion rates, empirically observed. However, in recent timesmore » increased tourism, industrial growth and petroleum extraction have exhibited the need for a better understanding of the atmospheric corrosion processes, as well as a realistic correlation to parameters such as time-of-wetness, levels of pollution by airborne salinity, atmospheric S0{sub 2} and corrosivity categories for the metals. To evaluate these parameters, five tests sites were selected following ISO recommendations. Three sites are marines atmospheres, one urban and one rural. Corrosion rates for commercial laminated Cu and carbon steel, as well as deposition rates of pollutants, were determined after one year exposure in the test sites. Applying the standard practice ISO 9223 a categorization of the corrosivity and of the level of pollutants was carried out. The marine environments were classified as of atmospheric corrosivity C{sub 5}, while the urban and the rural could be classified as C{sub 3}, respectively. The pollution values showed that the exposure sites were essentially contaminated with chloride with classification S{sub 1} for the rural site and S{sub 3} for the marine atmosphere.« less

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

Luke Chen; Hsu-Cheng Chang

An air pollutant (CO) distribution in a typical street canyon is simulated to evaluate pedestrian exposure. In this study, we consider factors those may affect the pollutant distribution in a typical street canyon. The considered factors include aspect ratio of a street canyon, atmospheric stability, traffic load and turbulent buoyancy effect. A two-dimensional domain that includes suburban roughness and urban street canyon is considered. The factors such as atmospheric stability, traffic load and turbulent buoyancy are imposed through the associated boundary conditions. With numerical simulation, the critical aspect ration of a street canyon the includes two vortices and results inmore » pollutant accumulation are found. The buoyant effect is found to raise the same pollutant concentration up to the position higher than the results come out from the case without buoyancy. The pedestrian exposure to the street air pollutant under various traffic loads and atmospheric stability are evaluated. This study conclude that the local building regulations that specify the building height/street width ratio will not cause significant pedestrian exposure to the street air pollution in most of traffic loads and atmospheric stability conditions.« less

Atmospheric Chemistry of Neonicotinoids Used in Urban Areas

NASA Astrophysics Data System (ADS)

Finlayson-Pitts, B. J.; Aregahegn, K.; Shemesh, D.; Gerber, R. B.

2016-12-01

Neonicotinoid (NN) pesticides are used extensively in both urban and agricultural settings to control sucking pests such as aphids, as well as for flea control for domestic pets. As a result, they are commonly found on surfaces that are exposed to the atmosphere. Imidacloprid (IMD) is one of the major NNs in pest control formulations. While there have been a number of studies of IMD reactions in solution, there are relatively few surface reactions that are relevant to atmospheric exposures. We report here laboratory studies of the photochemistry of IMD on surfaces in which quantum yields are measured and combined with absorption cross sections to estimate tropospheric lifetimes with respect to photolysis. Products identified using a combination of ATR-FTIR, DART-MS and ESI-MS include the desnitro and urea derivatives in the solid, and N2O in the gas phase. Quantum chemical calculations suggest a mechanism for the photolysis and production of these products. The implications for altering toxicity through atmospheric reactions will be discussed.

In Vitro Exposures in Diesel Exhaust Atmospheres: Resuspension of PM from Filters Verses Direct Deposition of PM from Air

PubMed Central

Lichtveld, Kim M.; Ebersviller, Seth M.; Sexton, Kenneth G.; Vizuete, William; Jaspers, Ilona; Jeffries, Harvey E.

2012-01-01

One of the most widely used in vitro particulate matter (PM) exposures methods is the collection of PM on filters, followed by resuspension in a liquid medium, with subsequent addition onto a cell culture. To avoid disruption of equilibria between gases and PM, we have developed a direct in vitro sampling and exposure method (DSEM) capable of PM-only exposures. We hypothesize that the separation of phases and post-treatment of filter-collected PM significantly modifies the toxicity of the PM compared to direct deposition, resulting in a distorted view of the potential PM health effects. Controlled test environments were created in a chamber that combined diesel exhaust with an urban-like mixture. The complex mixture was analyzed using both the DSEM and concurrently-collected filter samples. The DSEM showed that PM from test atmospheres produced significant inflammatory response, while the resuspension exposures at the same exposure concentration did not. Increasing the concentration of resuspended PM sixteen times was required to yield measurable IL-8 expression. Chemical analysis of the resuspended PM indicated a total absence of carbonyl compounds compared to the test atmosphere during the direct-exposures. Therefore, collection and resuspension of PM into liquid modifies its toxicity and likely leads to underestimating toxicity. PMID:22834915

A Modeling Investigation of Human Exposure to Select Traffic-Related Air Pollutants in the Tampa Area: Spatiotemporal Distributions of Concentrations, Social Distributions of Exposures, and Impacts of Urban Design on Both

NASA Astrophysics Data System (ADS)

Yu, Haofei

Increasing vehicle dependence in the United States has resulted in substantial emissions of traffic-related air pollutants that contribute to the deterioration of urban air quality. Exposure to urban air pollutants trigger a number of public health concerns, including the potential of inequality of exposures and health effects among population subgroups. To better understand the impact of traffic-related pollutants on air quality, exposure, and exposure inequality, modeling methods that can appropriately characterize the spatiotemporally resolved concentration distributions of traffic-related pollutants need to be improved. These modeling methods can then be used to investigate the impacts of urban design and transportation management choices on air quality, pollution exposures, and related inequality. This work will address these needs with three objectives: 1) to improve modeling methods for investigating interactions between city and transportation design choices and air pollution exposures, 2) to characterize current exposures and the social distribution of exposures to traffic-related air pollutants for the case study area of Hillsborough County, Florida, and 3) to determine expected impacts of urban design and transportation management choices on air quality, air pollution exposures, and exposure inequality. To achieve these objectives, the impacts of a small-scale transportation management project, specifically the '95 Express' high occupancy toll lane project, on pollutant emissions and nearby air quality was investigated. Next, a modeling method capable of characterizing spatiotemporally resolved pollutant emissions, concentrations, and exposures was developed and applied to estimate the impact of traffic-related pollutants on exposure and exposure inequalities among several population subgroups in Hillsborough County, Florida. Finally, using these results as baseline, the impacts of sprawl and compact urban forms, as well as vehicle fleet electrification, on air quality, pollution exposure, and exposure inequality were explored. Major findings include slightly higher pollutant emissions, with the exception of hydrocarbons, due to the managed lane project. Results also show that ambient concentration contributions from on-road mobile sources are disproportionate to their emissions. Additionally, processes not captured by the CALPUFF model, such as atmospheric formation, contribute substantially to ambient concentration levels of the secondary pollutants such as acetaldehyde and formaldehyde. Exposure inequalities for NOx, 1,3-butadiene, and benzene air pollution were found for black, Hispanic, and low income (annual household income less than $20,000) subgroups at both short-term and long-term temporal scales, which is consistent with previous findings. Exposure disparities among the subgroups are complex, and sometimes reversed for acetaldehyde and formaldehyde, due primarily to their distinct concentration distributions. Compact urban form was found to result in lower average NOx and benzene concentrations, but higher exposure for all pollutants except for NOx when compared to sprawl urban form. Evidence suggests that exposure inequalities differ between sprawl and compact urban forms, and also differ by pollutants, but are generally consistent at both short and long-term temporal scales. In addition, vehicle fleet electrification was found to result in generally lower average pollutant concentrations and exposures, except for NOx. However, the elimination of on-road mobile source emissions does not substantially reduce exposure inequality. Results and findings from this work can be applied to assist transportation infrastructure and urban planning. In addition, method developed here can be applied elsewhere for better characterization of air pollution concentrations, exposure and related inequalities.

Comparison of Tillandsia usneoides (Spanish moss) water and leachate dynamics between urban and pristine barrier island maritime oak forests

NASA Astrophysics Data System (ADS)

Van Stan, J. T.; Stubbins, A.; Reichard, J. S.; Wright, K.; Jenkins, R. B.

2013-12-01

Epiphyte coverage on forest canopies can drastically alter the volume and chemical composition of rainwater reaching soils. Along subtropical and tropical coastlines Tillandisa usneoides L. (Spanish moss), in particular, can envelop urban and natural tree crowns. Several cities actively manage their 'moss' covered forest to enhance aesthetics in the most active tourist areas (e.g., Savannah GA, St. Augustine FL, Charleston SC). Since T. usneoides survives through atmospheric water and solute exchange from specialized trichomes (scales), we hypothesized that T. usneoides water storage dynamics and leachate chemistry may be altered by exposure to this active urban atmosphere. 30 samples of T. usneoides from managed forests around the tourist center of Savannah, Georgia, USA were collected to compare with 30 samples from the pristine maritime live oak (Quercus virginiana Mill.) forests of a nearby undeveloped barrier island (St. Catherines Island, Georgia, USA). Maximum water storage capacities were determined via submersion (for all 60 samples) along with dissolved ion (DI) and organic matter (DOM) concentrations (for 15 samples each) after simulated throughfall generation using milliQ ultrapurified water. Further, DOM quality was evaluated (for 15 samples each) using absorbance and fluorescence spectroscopy (EEMS). Results show significant alterations to water storage dynamics, DI, DOM, and DOM quality metrics under urban atmospheric conditions, suggesting modified C and water cycling in urban forest canopies that may, in turn, influence intrasystem nutrient cycles in urban catchment soils or streams via runoff.

The Human Exposure Potential from Propylene Releases to the Environment

PubMed Central

Morgott, David A.

2018-01-01

A detailed literature search was performed to assess the sources, magnitudes and extent of human inhalation exposure to propylene. Exposure evaluations were performed at both the community and occupational levels for those living or working in different environments. The results revealed a multitude of pyrogenic, biogenic and anthropogenic emission sources. Pyrogenic sources, including biomass burning and fossil fuel combustion, appear to be the primary contributors to atmospheric propylene. Despite a very short atmospheric lifetime, measurable levels could be detected in highly remote locations as a result of biogenic release. The indoor/outdoor ratio for propylene has been shown to range from about 2 to 3 in non-smoking homes, which indicates that residential sources may be the largest contributor to the overall exposure for those not occupationally exposed. In homes where smoking takes place, the levels may be up to thirty times higher than non-smoking residences. Atmospheric levels in most rural regions are typically below 2 ppbv, whereas the values in urban levels are much more variable ranging as high as 10 ppbv. Somewhat elevated propylene exposures may also occur in the workplace; especially for firefighters or refinery plant operators who may encounter levels up to about 10 ppmv. PMID:29300328

Active Moss Biomonitoring of Atmospheric Trace Element Deposition in Belgrade Urban Area using ENAA and AAS

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

Anicic, M.; Tasic, M.; Tomasevic, M.

2007-11-26

Active biomonitoring of air quality in Belgrade, Serbia, was performed using the moss Sphagnum girgensohnii. Moss bags were exposed in parallel with and without irrigation respectively for four consecutive 3-month periods at three urban sites. Twenty-nine elements were determined in the exposed moss samples by ENAA and three (Cu, Cd, and Pb) by AAS. The relative accumulation factor (RAF) was greater than 1 for the majority of elements. Elements such as Cl, K, Rb and Cs, however, leached from the moss tissue during the exposure time. For all exposure periods, higher uptake in the irrigated moss bags was evident formore » Al, Cr, Fe, Cu, Zn, Sr, Pb, and Cd.« less

Development of a Healthy Urban Route Planner for cyclists and pedestrians in Amsterdam

NASA Astrophysics Data System (ADS)

van der Molen, Michiel; Ligtenberg, Arend; Vreugdenhil, Corne; Steeneveld, Gert-Jan

2017-04-01

Cities are hotspots of air pollution and heat stress, the exposure to which results in nuisance, health risks, cost of medication, reduced labour productivity and sick leave for citizens. Yet the air pollution and heat stress are spatially and temporally unevenly distributed over the city, depending on pollutant emissions, street design and atmospheric turbulent mixing and radiation. This spatiotemporal variation allows pedestrians and bikers to choose alternative routes to minimize their exposure, if the distribution is known. In this project, we develop a route planner for bicyclists and pedestrians for Amsterdam (NL), that proposes routes and departure times based on model simulations of weather and air quality. We use the WRF-Chem atmosphere and air quality model at unprecedented grid spacing of 100-m (Ronda et al, 2015, Super et al, 2016), with an underlying urban canopy model and NOx and PM10 emissions. The emissions by traffic are calculated based on observed traffic intensities and emission factors. An urban land use map will characterize urban density and street configuration to estimate urban heat storage (Attema et al, 2015). WRF-Chem runs will be issued daily for a lead time of 48 hours, resulting in forecast maps of temperature and pollutant concentrations that will be uniquely expressed in a metric that combines both threats. The hourly fields of this metric are provided to the route planner based on the open source routing library pgRouting to identify the more healthy routes on the route network of Amsterdam. The objectives of the healthy urban route planner are to raise awareness of heat and air quality issues in Amsterdam, to provide an innovative adaptation tool for citizens and tourists, to locate the most important bottlenecks in (the exposure to) air pollution and heat stress, and ultimately to test the readiness of the travellers to use the information and adapt the route. We expect to particularly target a group of lung- and cardiovascular patients, and elderly people. In the future the planner will be expanded with pollen information and possibly with real-time traffic information.

Factors influencing mobile source particulate matter emissions-to-exposure relationships in the Boston urban area.

PubMed

Greco, Susan L; Wilson, Andrew M; Hanna, Steven R; Levy, Jonathan I

2007-11-15

Benefit-cost and regulatory impact analyses often use atmospheric dispersion models with coarse resolution to estimate the benefits of proposed mobile source emission control regulations. This approach may bias health estimates or miss important intra-urban variability for primary air pollutants. In this study, we estimate primary fine particulate matter (PM2.5) intake fractions (iF; the fraction of a pollutant emitted from a source that is inhaled by the population) for each of 23 398 road segments in the Boston Metro Core area to evaluate the potential for intra-urban variability in the emissions-to-exposure relationship. We estimate iFs using the CAL3QHCR line source model combined with residential populations within 5000 m of each road segment. The annual average values for the road segments range from 0.8 to 53 per million, with a mean of 12 per million. On average, 46% of the total exposure is realized within 200 m of the road segment, though this varies from 0 to 93% largely due to variable population patterns. Our findings indicate the likelihood of substantial intra-urban variability in mobile source primary PM2.5 iF that accounting for population movement with time, localized meteorological conditions, and street-canyon configurations would likely increase.

Histopathologic changes of the nasal mucosa in southwest Metropolitan Mexico City inhabitants.

PubMed Central

Calderon-Garcidueñas, L.; Osorno-Velazquez, A.; Bravo-Alvarez, H.; Delgado-Chavez, R.; Barrios-Marquez, R.

1992-01-01

Metropolitan Mexico City (MMC) is one of the most polluted urban areas in the world. The authors characterized the morphologic nasal mucosal changes in short-term (less than 30 days) and long-term (more than 60 days) exposures to the polluted southwest MMC atmosphere with high levels of ozone and other contaminants versus a control group of subjects living in a nonpolluted, low-ozone Mexican port. Seventy-six inferior turbinate biopsies were examined. The control group showed normal mucociliary epithelium, whereas the short-exposure group displayed loss of normal epithelium, basal cell hyperplasia, and mild dysplasia (17.64%). In the long-term exposure group, 78.72% of dysplasias were found (59.45% mild and 40.54% moderate) together with severe loss of normal respiratory epithelium, prominent basal cell hyperplasia, squamous metaplasia, and submucosal vascular proliferation. Our findings suggest that southwest metropolitan Mexico City inhabitants develop histopathologic changes in their nasal mucosa on exposure to the polluted city atmosphere. Images Figure 5 Figure 6 Figure 7 PMID:1731527

SEMI-VOLATILE SPECIES IN PM 2.5: DEVELOPMENT AND VALIDATION OF INTEGRATED AND CONTINUOUS SAMPLERS FOR PM 2.5 RESEARCH OR EXPOSURE MONITORING.

EPA Science Inventory

Fine particulate matter (PM) in urban atmospheres contains substantial amounts of semi-volatile material (e.g. ammonium nitrate and semi-volatile organic compounds), some of which is lost when PM is sampled with a filter. This study addresses the hypothesis that the concentratio...

Biomonitoring of Air Condition in Urban Environment (with Regard to Irkutsk, Irkutsk region in Russia)

NASA Astrophysics Data System (ADS)

Belykh, L. I.

2017-11-01

The paper deals with the results of investigation into the contents and distribution of cancer-causing benzo(a)pyrene in the leaves of the trees that are common in the urban environment of Irkutsk. The degree of plant pollution is determined depending on the landscape and traffic exposure, on the mode of the plant material being prepared and on its type. The methodology for landscape geochemical biomonitoring is offered to be used at the stages of sample sorting and preparation and in the statistical treatment of the analysis results obtained. The possibility to use tree leaves as biotest materials for the urban atmosphere state control is considered in the paper.

A bacterial bioreporter panel to assay the cytotoxicity of atmospheric particulate matter

NASA Astrophysics Data System (ADS)

Kessler, Nivi; Schauer, James J.; Yagur-Kroll, Sharon; Melamed, Sahar; Tirosh, Ofir; Belkin, Shimshon; Erel, Yigal

2012-12-01

Numerous studies have demonstrated that elevated concentrations of suspended atmospheric particulate matter (PM) are associated with adverse health effects. In order to minimize the adverse public health effects of atmospheric PM by exposure management, there is a need for a greater understanding of the toxic mechanisms and the components that are responsible for the toxic effects. The aim of this study was to utilize bioassay techniques to investigate these aspects. For this purpose a reporter panel of 9 genetically engineered bacterial (Escherichia coli) strains was composed. Each panel member was designed to report on a different stress condition with a measurable light signal produced by the luciferase enzyme. Toxic mechanisms and components were studied using six anthropogenic PM source samples, including two vehicle combustion particles, three coal fly ash (CFA) samples and an urban dust sample. The most prominent outcome of the panel exposure results were broad panel responses observed for two of the CFA samples, indicating oxidative stress, respiration inhibition and iron deficiency. These responses were relieved when the samples were treated with EDTA, a non-specific metal chelator, suggesting the involvement of metals in the observed effects. Bioavailability analysis of the samples suggests that chromium was related to the toxic responses induced by two of the CFA samples. Oxidative stress was also observed in several samples of ambient atmospheric aerosols and excess metal toxicity in an urban dust sample collected in a parking lot. The reporter panel approach, as demonstrated in this study, has the potential of providing novel insights as to the mechanisms of atmospheric PM toxicity. Furthermore, combining the panel's results with bioavailability data can enlighten about the role of different PM components in the observed toxicity.

Posttranslational modification of Birch and Ragweed allergen proteins by common gas phase pollutants, NO2 and O3

NASA Astrophysics Data System (ADS)

Mahmood, M. A.; Pope, F.; Bloss, W.

2015-12-01

The global incidence of hay fever has been rising for decades, however, the underlying reasons behind this rise remain unclear. It is hypothesized that exposure of pollen to common gas phase pollutants, such as nitrogen dioxide (NO2) and ozone (O3), increases the allergenicity of the pollen and thus increases hay fever incidence. Since atmospheric pollutants tend to have greater concentrations within urban areas (in particular NO2) the hypothesis suggests that greater allergenicity should occur in urban areas. Indeed, several studies do suggest higher hay fever incidence within urban areas compared to rural areas. Previous published work suggests a link between increased allergies with changes in the chemical composition of the pollen protein via posttranslational modification of the protein. This study investigates the posttranslational modification of two highly allergenic pollen species (Birch and Ragweed) that are common in Europe. Within the laboratory, we expose pollen grains to atmospherically relevant exposures of gas phase NO2, O3 and other common gas phase oxidants under a range of environmentally relevant conditions. The effects of the environmentally relevant exposures on the biochemistry of the pollen grains were probed using a proteomic approach (liquid chromatography coupled ultra-high resolution spectrometer). Our findings indicate the interaction between gas phase pollutants and pollen cause protein specific modifications; in particular, nitration occurs upon tyrosine residues and nitrosylation on cysteine residues. Possibly, these modifications may affect the immune response of the pollen protein, which may suggest a possible reason for increased allergies in reaction to such biologically altered protein. The laboratory-derived results will be supported with a time series analysis of asthma incidence rates for the London area, which take into account the pollen count, and pollutant concentrations. The implications of the results will be discussed in terms of better planning of city infrastructure. In particular, the relevance of the results upon urban tree planting schemes will be put into context.

Fine-Scale Exposure to Allergenic Pollen in the Urban Environment: Evaluation of Land Use Regression Approach.

PubMed

Hjort, Jan; Hugg, Timo T; Antikainen, Harri; Rusanen, Jarmo; Sofiev, Mikhail; Kukkonen, Jaakko; Jaakkola, Maritta S; Jaakkola, Jouni J K

2016-05-01

Despite the recent developments in physically and chemically based analysis of atmospheric particles, no models exist for resolving the spatial variability of pollen concentration at urban scale. We developed a land use regression (LUR) approach for predicting spatial fine-scale allergenic pollen concentrations in the Helsinki metropolitan area, Finland, and evaluated the performance of the models against available empirical data. We used grass pollen data monitored at 16 sites in an urban area during the peak pollen season and geospatial environmental data. The main statistical method was generalized linear model (GLM). GLM-based LURs explained 79% of the spatial variation in the grass pollen data based on all samples, and 47% of the variation when samples from two sites with very high concentrations were excluded. In model evaluation, prediction errors ranged from 6% to 26% of the observed range of grass pollen concentrations. Our findings support the use of geospatial data-based statistical models to predict the spatial variation of allergenic grass pollen concentrations at intra-urban scales. A remote sensing-based vegetation index was the strongest predictor of pollen concentrations for exposure assessments at local scales. The LUR approach provides new opportunities to estimate the relations between environmental determinants and allergenic pollen concentration in human-modified environments at fine spatial scales. This approach could potentially be applied to estimate retrospectively pollen concentrations to be used for long-term exposure assessments. Hjort J, Hugg TT, Antikainen H, Rusanen J, Sofiev M, Kukkonen J, Jaakkola MS, Jaakkola JJ. 2016. Fine-scale exposure to allergenic pollen in the urban environment: evaluation of land use regression approach. Environ Health Perspect 124:619-626; http://dx.doi.org/10.1289/ehp.1509761.

Characterization of atmospheric emission sources in lichen from metal and organic contaminant patterns.

PubMed

Ratier, Aude; Dron, Julien; Revenko, Gautier; Austruy, Annabelle; Dauphin, Charles-Enzo; Chaspoul, Florence; Wafo, Emmanuel

2018-03-01

Lichen samples from contrasted environments, influenced by various anthropic activities, were investigated focusing on the contaminant signatures according to the atmospheric exposure typologies. Most of the contaminant concentrations measured in the 27 lichen samples, collected around the industrial harbor of Fos-sur-Mer (France), were moderate in rural and urban environments, and reached extreme levels in industrial areas and neighboring cities (Al up to 6567 mg kg -1 , Fe 42,398 mg kg -1 , or ΣPAH 1417 μg kg -1 for example). At the same time, a strong heterogeneity was noticed in industrial samples while urban and rural ones were relatively homogeneous. Several metals could be associated to steel industry (Fe, Mn, Cd), road traffic, and agriculture (Sb, Cu, Sn), or to a distinct chemical installation (Mo). As well, PCDFs dominated in industrial samples while PCDDs prevailed in urban areas. The particularities observed supported the purpose of this work and discriminated the contributions of various atmospheric pollution emission sources in lichen samples. A statistical approach based on principal component analysis (PCA) was applied and resolved these potential singularities into specific component factors. Even if a certain degree of mixing of the factors is pointed out, relevant relationships were observed with several atmospheric emission sources. By this methodology, the contribution of industrial emissions to the atmospheric metal, PAH, PCB, and PCDD/F levels was roughly estimated to be 60.2%, before biomass burning (10.2%) and road traffic (3.8%). These results demonstrate that lichen biomonitoring offers an encouraging perspective of spatially resolved source apportionment studies.

Evaluation of regional and local atmospheric dispersion models for the analysis of traffic-related air pollution in urban areas

NASA Astrophysics Data System (ADS)

Fallah-Shorshani, Masoud; Shekarrizfard, Maryam; Hatzopoulou, Marianne

2017-10-01

Dispersion of road transport emissions in urban metropolitan areas is typically simulated using Gaussian models that ignore the turbulence and drag induced by buildings, which are especially relevant for areas with dense downtown cores. To consider the effect of buildings, street canyon models are used but often at the level of single urban corridors and small road networks. In this paper, we compare and validate two dispersion models with widely varying algorithms, across a modelling domain consisting of the City of Montreal, Canada accounting for emissions of more 40,000 roads. The first dispersion model is based on flow decomposition into the urban canopy sub-flow as well as overlying airflow. It takes into account the specific height and geometry of buildings along each road. The second model is a Gaussian puff dispersion model, which handles complex terrain and incorporates three-dimensional meteorology, but accounts for buildings only through variations in the initial vertical mixing coefficient. Validation against surface observations indicated that both models under-predicted measured concentrations. Average weekly exposure surfaces derived from both models were found to be reasonably correlated (r = 0.8) although the Gaussian dispersion model tended to underestimate concentrations around the roadways compared to the street canyon model. In addition, both models were used to estimate exposures of a representative sample of the Montreal population composed of 1319 individuals. Large differences were noted whereby exposures derived from the Gaussian puff model were significantly lower than exposures derived from the street canyon model, an expected result considering the concentration of population around roadways. These differences have large implications for the analyses of health effects associated with NO2 exposure.

Personal inhalation exposure to polycyclic aromatic hydrocarbons and their nitro-derivatives in rural residents in northern Thailand.

PubMed

Orakij, Walaiporn; Chetiyanukornkul, Thaneeya; Chuesaard, Thanyarat; Kaganoi, Yuichi; Uozaki, Waka; Homma, Chiharu; Boongla, Yaowatat; Tang, Ning; Hayakawa, Kazuichi; Toriba, Akira

2017-09-18

A personal inhalation exposure and cancer risk assessment of rural residents in Lampang, Thailand, was conducted for the first time. This highlighted important factors that may be associated with the highest areal incidence of lung cancer. Personal exposure of rural residents to polycyclic aromatic hydrocarbons (PAHs) and their nitro-derivatives (NPAHs) through inhalation of fine particulate matter (PM 2.5 ) was investigated in addition to stationary air sampling in an urban area. The personal exposure of the subjects to PM 2.5 ranged from 44.4 to 316 μg/m 3 , and the concentrations of PAHs (4.2-224 ng/m 3 ) and NPAHs (120-1449 pg/m 3 ) were higher than those at the urban site, indicating that personal exposure was affected by microenvironments through individual activities. The smoking behaviors of the rural residents barely affected their exposure to PAHs and NPAHs compared to other sources. The most important factor concerning the exposure of rural populations to PAHs was cooking activity, especially the use of charcoal open fires. The emission sources for rural residents and urban air were evaluated using diagnostic ratios, 1-nitropyrene/pyrene, and benzo[a]pyrene/benzo[ghi]perylene. Their analyses showed a significant contribution to emission from residents' personal activities in addition to the atmospheric environment. Furthermore, the personal inhalation cancer risks for all rural subjects exceeded the USEPA guideline value, suggesting that the residents have a potentially increased cancer risk. The use of open fires showed the highest cancer risk. A reduction in exposure to air pollutants for the residents could potentially be achieved by using clean fuel such as liquid petroleum gas or electricity for daily cooking.

Airborne bacteria associated with corrosion of mild steel 1010 and aluminum alloy 1100.

PubMed

Rajasekar, Aruliah; Xiao, Wang; Sethuraman, Manivannan; Parthipan, Punniyakotti; Elumalai, Punniyakotti

2017-03-01

A novel approach to measure the contribution of airborne bacteria on corrosion effects of mild steel (MS) and aluminum alloy (AA) as a function of their exposure period, and the atmospheric chemical composition was investigated at an urban industrial coastal site, Singapore. The 16S rRNA and phylogenetic analyses showed that Firmicutes are the predominant bacteria detected in AA and MS samples. The dominant bacterial groups identified were Bacillaceae, Staphylococcaceae, and Paenibacillaceae. The growth and proliferation of these bacteria could be due to the presence of humidity and chemical pollutants in the atmosphere, leading to corrosion. Weight loss showed stronger corrosion resistance of AA (1.37 mg/cm 2 ) than MS (26.13 mg/cm 2 ) over the exposure period of 150 days. The higher corrosion rate could be a result of simultaneous action of pollutants and bacterial exopolysaccharides on the metal surfaces. This study demonstrates the significant involvement of airborne bacteria on atmospheric corrosion of engineering materials.

EFFECT OF AN ACID RAIN ENVIRONMENT ON LIMESTONE SURFACES.

USGS Publications Warehouse

Mossotti, Victor G.; Lindsay, James R.; Hochella, Michael F.

1987-01-01

Salem limestone samples were exposed to weathering for 1 y in several urban and one rural environments. Samples exposed in the rural location were chemically indistinguishable from the freshly quarried limestone, whereas all samples collected from urban exposure sites developed gypsum stains on the ground-facing surfaces where the stones were not washed by precipitation. The gas-solid reaction of SO//2 with calcite was selected for detailed consideration. It appears from the model that under arid conditions, the quantity of stain deposited on an unwashed surface is independent of atmospheric SO//2 concentration once the surface has been saturated with gypsum. Under wet conditions, surface sulfation and weight loss are probably dominated by mechanisms involving wet stone. However, if the rain events are frequent and delimited by periods of dryness, the quantity of gypsum produced by a gas-solid reaction mechanism should correlate with both the frequency of rain events and the atmospheric SO//2 level.

A personal exposure study employing scripted activities and paths in conjunction with atmospheric releases of perfluorocarbon tracers in Manhattan, New York

PubMed Central

LIOY, PAUL J; VALLERO, DANIEL; FOLEY, GARY; GEORGOPOULOS, PANOS; HEISER, JOHN; WATSON, TOM; REYNOLDS, MICHAEL; DALOIA, JAMES; TONG, SAI; ISUKAPALLI, SASTRY

2014-01-01

A personal exposure study was conducted in New York City as part of the Urban Dispersion Program (UDP). It examined the contact of individuals with four harmless perflourocarbon tracers (PFT) released in Midtown Manhattan with approval by city agencies at separate locations, during two types of experiments, completed during each release period. Two continuous 1 h release periods separated by a 1.5 h ventilation time were completed on 3 October 2005. Stationary site and personal exposure measurements were taken during each period, and the first half hour after the release ended. Two types of scripted exposure activities are reported: Outdoor Source Scale, and Outdoor Neighborhood Scale; requiring 1- and 10-min duration samples, respectively. The results showed that exposures were influenced by the surface winds, the urban terrain, and the movements of people and vehicles typical in urban centers. The source scale exposure data indicated that local conditions significantly affected the distribution of each tracer, and consequently the exposures. The highest PFT exposures resulted from interaction of the scripted activities with local surface conditions. The range measured for 1- min exposures were large with measured values exceeding 5000 ppqv (parts per quadrillion by volume). The neighborhood scale measurements quantified exposures at distances up to seven blocks away from the release points. Generally, but not always, the PFT levels returned quickly to zero indicating that after cessation of the emissions the concentrations decrease rapidly, and reduce the intensity of local exposures. The near source and neighborhood personal exposure route results provided information to establish a baseline for determining how a release could affect both the general public and emergency responders, and evaluate the adequacy of re-entry or exit strategies from a local area. Finally, the data also show that local characteristics can produce “hot spots”. PMID:17505505

Urban cyclist exposure to fine particle pollution in a rapidly growing city

NASA Astrophysics Data System (ADS)

Luce, B. W.; Barrett, T. E.; Ponette-González, A.

2017-12-01

Urban cyclists are exposed to elevated atmospheric concentrations of fine particulate matter (particles <2.5 µm or PM2.5). Major urban sources of PM2.5 include the incomplete combustion of fossil fuels from vehicle exhaust, which is emitted directly into cyclists' "breathing zone." In cities, human exposure to PM2.5 is a concern because its small size allows it to be inhaled deeper into the lungs than most particles. The aim of this research is to determine "hotspots" (locations with high PM2.5 concentrations) within the Dallas-Fort Worth Metroplex, Texas, where urban cyclists are most exposed to fine particle pollution. Recent research indicates that common exposure hotspots include traffic signals, junctions, bus stations, parking lots, and inclined streets. To identify these and other hotspots, a bicycle equipped with a low-cost, portable, battery-powered particle counter (Dylos 1700) coupled with a Trimble Geo 5T handheld Global Positioning System (GPS; ≤1 m ± resolution) will be used to map and measure particle mass concentrations along predetermined routes. Measurements will be conducted during a consecutive four-month period (Sep-Dec) during morning and evening rush hours when PM2.5 levels are generally highest, as well as during non-rush hour times to determine background concentrations. PM2.5 concentrations will be calculated from particle counts using an equation developed by Steinle et al. (2015). In addition, traffic counts will be conducted along the routes coinciding with the mobile monitoring times. We will present results on identified "hotspots" of high fine particle concentrations and PM2.5 exposure in the City of Denton, where particle pollution puts urban commuters most at risk, as well as average traffic counts from monitoring times. These data can be used to determine pollution mitigation strategies in rapidly growing urban areas.

Comparative Assessment of Particulate Air Pollution Exposure from Municipal Solid Waste Incinerator Emissions

PubMed Central

Ashworth, Danielle C.; Fuller, Gary W.; Toledano, Mireille B.; Font, Anna; Elliott, Paul; Hansell, Anna L.; de Hoogh, Kees

2013-01-01

Background. Research to date on health effects associated with incineration has found limited evidence of health risks, but many previous studies have been constrained by poor exposure assessment. This paper provides a comparative assessment of atmospheric dispersion modelling and distance from source (a commonly used proxy for exposure) as exposure assessment methods for pollutants released from incinerators. Methods. Distance from source and the atmospheric dispersion model ADMS-Urban were used to characterise ambient exposures to particulates from two municipal solid waste incinerators (MSWIs) in the UK. Additionally an exploration of the sensitivity of the dispersion model simulations to input parameters was performed. Results. The model output indicated extremely low ground level concentrations of PM10, with maximum concentrations of <0.01 μg/m3. Proximity and modelled PM10 concentrations for both MSWIs at postcode level were highly correlated when using continuous measures (Spearman correlation coefficients ~ 0.7) but showed poor agreement for categorical measures (deciles or quintiles, Cohen's kappa coefficients ≤ 0.5). Conclusion. To provide the most appropriate estimate of ambient exposure from MSWIs, it is essential that incinerator characteristics, magnitude of emissions, and surrounding meteorological and topographical conditions are considered. Reducing exposure misclassification is particularly important in environmental epidemiology to aid detection of low-level risks. PMID:23935644

Challenges associated with projecting urbanization-induced heat-related mortality.

PubMed

Hondula, David M; Georgescu, Matei; Balling, Robert C

2014-08-15

Maricopa County, Arizona, anchor to the fastest growing megapolitan area in the United States, is located in a hot desert climate where extreme temperatures are associated with elevated risk of mortality. Continued urbanization in the region will impact atmospheric temperatures and, as a result, potentially affect human health. We aimed to quantify the number of excess deaths attributable to heat in Maricopa County based on three future urbanization and adaptation scenarios and multiple exposure variables. Two scenarios (low and high growth projections) represent the maximum possible uncertainty range associated with urbanization in central Arizona, and a third represents the adaptation of high-albedo cool roof technology. Using a Poisson regression model, we related temperature to mortality using data spanning 1983-2007. Regional climate model simulations based on 2050-projected urbanization scenarios for Maricopa County generated distributions of temperature change, and from these predicted changes future excess heat-related mortality was estimated. Subject to urbanization scenario and exposure variable utilized, projections of heat-related mortality ranged from a decrease of 46 deaths per year (-95%) to an increase of 339 deaths per year (+359%). Projections based on minimum temperature showed the greatest increase for all expansion and adaptation scenarios and were substantially higher than those for daily mean temperature. Projections based on maximum temperature were largely associated with declining mortality. Low-growth and adaptation scenarios led to the smallest increase in predicted heat-related mortality based on mean temperature projections. Use of only one exposure variable to project future heat-related deaths may therefore be misrepresentative in terms of direction of change and magnitude of effects. Because urbanization-induced impacts can vary across the diurnal cycle, projections of heat-related health outcomes that do not consider place-based, time-varying urban heat island effects are neglecting essential elements for policy relevant decision-making. Copyright © 2014 Elsevier B.V. All rights reserved.

Real time outdoor exposure testing of solar cell modules and component materials

NASA Technical Reports Server (NTRS)

Anagnostou, E.; Forestieri, A. F.

1977-01-01

Plastic samples, solar cell modules, and sub-modules were exposed at test sites in Florida, Arizona, Puerto Rico, and Cleveland, Ohio, in order to determine materials suitable for use in solar cell modules with a proposed 20-year lifetime. Various environments were encountered including subtropical, subtropical with a sea air atmosphere, desert, rain forest, normal urban, and urban-polluted. The samples were exposed for periods up to six months. Materials found not suitable were polyurethane, polyester, Kapton, Mylar, and UV-stabilized Lexan. Suitable materials were acrylic, FEP-A, and glass. The results of exposure of polyvinylidene fluoride were dependent on the specific formulation, but several types appear suitable. RTV silicone rubber (clear) appears to pick up and hold dirt both as a free film and as a potting medium for modules. The results indicate that dirt accumulation and cleanability are important factors in the selection of solar cell module covers and encapsulants.

Transplantation of epiphytic bioaccumulators (Tillandsia capillaris) for high spatial resolution biomonitoring of trace elements and point sources deconvolution in a complex mining/smelting urban context

NASA Astrophysics Data System (ADS)

Goix, Sylvaine; Resongles, Eléonore; Point, David; Oliva, Priscia; Duprey, Jean Louis; de la Galvez, Erika; Ugarte, Lincy; Huayta, Carlos; Prunier, Jonathan; Zouiten, Cyril; Gardon, Jacques

2013-12-01

Monitoring atmospheric trace elements (TE) levels and tracing their source origin is essential for exposure assessment and human health studies. Epiphytic Tillandsia capillaris plants were used as bioaccumulator of TE in a complex polymetallic mining/smelting urban context (Oruro, Bolivia). Specimens collected from a pristine reference site were transplanted at a high spatial resolution (˜1 sample/km2) throughout the urban area. About twenty-seven elements were measured after a 4-month exposure, also providing new information values for reference material BCR482. Statistical power analysis for this biomonitoring mapping approach against classical aerosols surveys performed on the same site showed the better aptitude of T. Capillaris to detect geographical trend, and to deconvolute multiple contamination sources using geostatistical principal component analysis. Transplanted specimens in the vicinity of the mining and smelting areas were characterized by extreme TE accumulation (Sn > Ag > Sb > Pb > Cd > As > W > Cu > Zn). Three contamination sources were identified: mining (Ag, Pb, Sb), smelting (As, Sn) and road traffic (Zn) emissions, confirming results of previous aerosol survey.

Studying urban land-atmospheric interactions by coupling an urban canopy model with a single column atmospheric models

NASA Astrophysics Data System (ADS)

Song, J.; Wang, Z.

2013-12-01

Studying urban land-atmospheric interactions by coupling an urban canopy model with a single column atmospheric models Jiyun Song and Zhi-Hua Wang School of Sustainable Engineering and the Built Environment, Arizona State University, PO Box 875306, Tempe, AZ 85287-5306 Landuse landcover changes in urban area will modify surface energy budgets, turbulent fluxes as well as dynamic and thermodynamic structures of the overlying atmospheric boundary layer (ABL). In order to study urban land-atmospheric interactions, we coupled a single column atmospheric model (SCM) to a cutting-edge single layer urban canopy model (SLUCM). Modification of surface parameters such as the fraction of vegetation and engineered pavements, thermal properties of building and pavement materials, and geometrical features of street canyon, etc. in SLUCM dictates the evolution of surface balance of energy, water and momentum. The land surface states then provide lower boundary conditions to the overlying atmosphere, which in turn modulates the modification of ABL structure as well as vertical profiles of temperature, humidity, wind speed and tracer gases. The coupled SLUCM-SCM model is tested against field measurements of surface layer fluxes as well as profiles of temperature and humidity in the mixed layer under convective conditions. After model test, SLUCM-SCM is used to simulate the effect of changing urban land surface conditions on the evolution of ABL structure and dynamics. Simulation results show that despite the prescribed atmospheric forcing, land surface states impose significant impact on the physics of the overlying vertical atmospheric layer. Overall, this numerical framework provides a useful standalone modeling tool to assess the impacts of urban land surface conditions on the local hydrometeorology through land-atmospheric interactions. It also has potentially far-reaching implications to urban ecohydrological services for cities under future expansion and climate challenges.

Urban air carcinogens and their effects on health

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

Lechner, J.F.

1994-11-01

Airborne carcinogens may be relevant especially in metropolitan regions with extreme smog as a primary cause of lung cancer. Lung cancer is most common in urban environs and the incidence directly correlates with the size of the city. In addition, several, but not all formal epidemiological studies also suggest a positive correlation between lung cancer incidence and the intensity of air pollution exposure. There is further support for a role of air pollution; as of 1993, 4.4% of all of the bronchogenic adenocarcinoma cancer cases among Mexicans living in industrialized cities are under 40 years of age. It is plausiblemore » that chronic inhalation of automobile combustion products, factory emissions, and/or radon is at least partially responsible for the higher incidence of lung cancer exemplified by the never-smoking urban residents. The exceptionally high incidence of lung cancer cases among never-smokers living in highly industrialized Mexican cities offers a unique opportunity to use molecular epidemiology to test whether chronic inhalation of atmospheric pollutants increases the risk for this disease. Overall, the analysis of the genetic alterations in two cancer genes, and possibly the hprt locus should give new insight as to whether the urban never-smokers developed their cancers because of exposure to environmental pollutants.« less

Black soiling of an architectural limestone during two-year term exposure to urban air in the city of Granada (S Spain).

PubMed

Urosevic, Maja; Yebra-Rodríguez, Africa; Sebastián-Pardo, Eduardo; Cardell, Carolina

2012-01-01

A two-year term aging test was carried out on a building limestone under different urban conditions in the city of Granada (Southern Spain) to assess its Cultural Heritage sustainability. For this purpose stone tablets were placed vertically at four sites with contrasting local pollution micro-environments and exposure conditions (rain-sheltered and unsheltered). The back (rain-sheltered) and the front (rain-unsheltered) faces of the stone tablets were studied for each site. The soiling process (surface blackening) was monitored through lightness (ΔL*) and chroma changes (ΔC*). Additionally atmospheric particles deposited on the stone surfaces and on PM10 filters during the exposure time were studied through a multianalytical approach including scanning electron microscopy (SEM-EDX), transmission electron microscopy (TEM) and micro-Raman spectroscopy. The identified atmospheric particles (responsible for stone soiling) were mainly soot and soil dust particles; also fly ash and aged salt particles were found. The soiling process was related to surface texture, exposure conditions and proximity to dense traffic streets. On the front faces of all stones, black soiling and surface roughness promoted by differential erosion between micritic and sparitic calcite were noticed. Moreover, it was found that surface roughness enhanced a feedback process that triggers further black soiling. The calculated effective area coverage (EAC) by light absorbing dust ranged from 10.2 to 20.4%, exceeding by far the established value of 2% EAC (limit perceptible to the human eye). Soiling coefficients (SC) were estimated based on square-root and bounded exponential fittings. Estimated black carbon (BC) concentration resulted in relatively similar SC for all studied sites and thus predicts the soiling process better than using particulate matter (PM10) concentration. Copyright © 2011 Elsevier B.V. All rights reserved.

Pollution characteristics and health risk assessment of phthalate esters in urban soil in the typical semi-arid city of Xi'an, Northwest China.

PubMed

Wang, Lijun; Liu, Mengmei; Tao, Wendong; Zhang, Wenjuan; Wang, Li; Shi, Xingmin; Lu, Xinwei; Li, Xiaoping

2018-01-01

A total of 62 urban soil samples were collected in the city of Xi'an in Northwest China, and analyzed for six U.S. Environmental Protection Agency priority phthalate esters (PAEs). Unlike earlier studies on PAEs in agricultural soil as well as urban soil in humid climates, this paper for the first time comprehensively assessed pollution characteristics and health risks of human exposure to PAEs in urban soil in a typical semi-arid climate. The total concentrations of the six PAEs (Σ6PAEs) in the urban soil varied between 193.0 and 19146.4 μg kg -1 with a mean of 1369.3 μg kg -1 . The PAEs were dominated by di-n-butyl phthalate and di(2-ethylhexyl) phthalate. Magnetic susceptibility and soil texture were controlling factors influencing the concentrations of PAEs in the urban soil. The concentrations of benzyl butyl phthalate, di(2-ethylhexyl) phthalate, and Σ6PAEs increased from the first to third ring roads, while the concentrations of di-n-octyl phthalate decreased. Relatively higher levels of PAEs were observed in industrial, traffic, and residential areas. The PAEs in the urban soil originated mainly from the application of plasticizers or additives, use of cosmetics and personal care products, emissions of construction materials and home furnishings, industrial processes, and atmospheric deposition. The concentrations of some PAEs in the urban soil exceeded soil allowable concentrations and environmental risk levels. The non-cancer and carcinogenic risks of human exposure to the PAEs were relatively low. Copyright © 2017 Elsevier Ltd. All rights reserved.

CO Pollution: a comparative study during high traffic conditions in the cities of Athens, Naples and Islamabad. Health impacts

NASA Astrophysics Data System (ADS)

Polichetti, Juliano; Grigoropoulos, Konstantinos; Ferentinos, George; Tselentis, Vasilios; Nastos, Panagiotis; Xatzioakeimidis, Konstantinos; Dimas, Konstantinos; Khan, Ubaidullah

2010-05-01

Since the 19th century anthropogenic activities in urban areas have increased dramatically due to socio-economic evolution, increased urbanization and transport needs. Fifty seven years ago London experienced the impacts of an acute atmospheric pollution episode, due to elevated levels of black carbon aerosols (BC) and SO2, leading to the realization that uncontrolled emissions to the atmosphere lead to severe impacts on human health. Many large cities (Mega cities) in the developed and developing world have, for the last two decades, been plagued by high levels of atmospheric pollution, a problem that the European and worldwide scientific community are at present studying with measurable success. However, due to rapid industrial development and the ever increasing traffic, many more studies are required to support decision makers and governments on measures to reduce atmospheric pollution and mitigate the associated serious health effects on the population. Registered health problems are numerous and dramatic in all ages groups, but particularly so in infants, and patients suffering from chronic diseases due to increased levels of pollutants and nocive substance inhaled, entering the lungs and blood stream and finally being deposited in several organs. Recent studies indicate that cardiac arrhythmias associated to increased atmospheric pollution pose a serious threat to human health. K.N.Grigoropoulos,et al.2008. This study is based on monitoring and mapping CO levels in six areas 3 different cities i.e. Athens, Naples and Islamabad, the objective being to present and analyze the spatial and temporal variability of carbon monoxide (CO) levels leading to the estimation of the concentration levels and the quantities inhaled by pedestrians on a daily basis. It is well know that exposure to carbon monoxide concentration values in excess of 200ppm for 2-3 h usually create headaches, tiredness, fatigue and nausea, whereas human exposure of values of 800 ppm for over three hours, are fatal. The findings of this research indicate that although CO concentrations remain at low levels throughout the measurement period, several peaks of high CO concentration are obtained, in many instances of several minutes duration, which are incompatible with public health levels and conditions for the afore mentioned cities. This research is yet another reminder that it is timely and necessary for the European Community to re examinate and evaluate the framework pertinent to CO emissions and levels in the urban ambient atmosphere.

[Atmospheric Polybrominated Diphenyl Ethers in Eight Cities of China: Pollution Characteristics and Human Exposure].

PubMed

Lin, Hai-tao; Li, Qi-lu; Zhang, Gan; Li, Jun

2016-01-15

The gas and particle samples of eight cities were collected by high flow active air sampler in the Eastern and Western China and eight congeners of polybrominated diphenyl ethers were analyzed. The results showed that the concentration of BDE-28 (tri-BDE) in the gas-phase (three bromide components) was the highest, which was different from previous studies where BDE-99 and-47 were the predominant homologues in the gas-phase while the concentration of BDE-209 [(25.4 ± 124) pg · m⁻³] in particle-phase was the highest. The atmospheric concentrations of PBDEs in Beijing and Guangzhou were relatively higher, especially the BDE-209 concentration in particle phases of Guangzhou was two orders higher than those of other cities. However, the atmospheric concentrations of PBDEs declined significantly when compared with the data from previous studies. Meanwhile, the results indicated that the gas-phase concentrations decreased slowly and the particle-phase concentrations decreased rapidly. Combined with the results of correlation analysis, this phenomenon might be ascribed to the ceased commercial production of penta- and octa-BDE, the light degradation of high bromide components and reduced concentrations of atmospheric particles in urban area. Inhalation exposure for infants was about 2-3 times higher than that of adults. This reflected that the potential health risk of atmospheric PBDEs in city for residents, especially infants and young children, should not be ignored.

Assessment of human health risk related to metals by the use of biomonitors in the province of Córdoba, Argentina.

PubMed

Carreras, Hebe A; Wannaz, Eduardo D; Pignata, María L

2009-01-01

The evaluation of metal contents in the environment is of vital importance for the assessment of human exposure. Thus the species Usnea amblyoclada, Ramalina celastri and Tillandsia capillaris were tested as bioaccumulators of transition metals in the urban area of Córdoba city, Argentina. The level of metals on biomonitors was compared to that of total deposition samples. All three species discriminated zones within the urban area of Córdoba city with different pollution levels; they revealed high levels of Zn in the downtown area and confirmed high levels of some transition metals in an industrial area. The correlation analysis revealed that the lichen R. celastri had the highest correlation rates with total deposition samples, suggesting it is a valuable biomonitor of atmospheric pollution. A significant relationship was also observed between respiratory diseases in children and the contents of metal accumulated in R. celastri and T. capillaris, indicating their usefulness when assessing human exposure to metals.

Wind-Tunnel Modeling of Flow Diffusion over an Urban Complex.

DTIC Science & Technology

URBAN AREAS, *ATMOSPHERIC MOTION, *AIR POLLUTION, ATMOSPHERIC MOTION, WIND TUNNEL MODELS, HEAT, DIFFUSION , TURBULENT BOUNDARY LAYER, WIND, SKIN FRICTION, MATHEMATICAL MODELS, URBAN PLANNING, INDIANA.

Characterising the influence of atmospheric mixing state on Urban Heat Island Intensity using Radon-222

NASA Astrophysics Data System (ADS)

Chambers, Scott D.; Podstawczyńska, Agnieszka; Williams, Alastair G.; Pawlak, Włodzimierz

2016-12-01

Characterisation of the effects of varying atmospheric mixing states (stability) in urban climate studies has historically been hampered by problems associated with the complexity of the urban environment, representativity of measurement techniques, and the logistical and financial burdens of maintaining multiple long-term comprehensive measurement sites. These shortcomings, together with a lack of a consistent measurement approach, have limited our ability to understand the physical processes contributing to the urban heat island effect. In this study, we analyse 4 years of continuous hourly near-surface meteorological and atmospheric radon data from an urban-rural site pair in central Poland. A recently-developed radon-based stability classification technique, previously developed for urban pollution characterisation, is employed to characterise the Urban Heat Island Intensity (UHII) and other climatic factors over the full diurnal cycle by season and atmospheric mixing state. By characterising the UHII over a range of atmospheric mixing states in a statistically robust way, this technique provides an effective tool for assessing the efficacy of mitigation measures for urban climate effects in a consistent way over timescales of years to decades. The consistency of approach, ease of application, and unprecedented clarity of findings, provide a strong argument for atmospheric radon observations to be included as part of the 'standard measurement suite' for urban climate monitoring networks for non-coastal cities.

The sources and fate of (210)Po in the urban air: A review.

PubMed

Długosz-Lisiecka, Magdalena

2016-09-01

The origin of (210)Po activity and its fluctuations in the air are discussed in this paper. In the case of atmospheric aerosol samples, a comparison of the (210)Po/(210)Pb and (210)Bi/(210)Pb activity ratios makes it possible not only to determine aerosol residence times but also to appraise the contribution of the unsupported (210)Po coming from other sources than (222)Rn decay, such as human industrial activities, especially coal combustion. A simple mathematical method makes it possible to observe the seasonal fluctuations of the anthropogenic excess of (210)Po in the urban air. The average doses of (210)Po intake with food (including drinking water) and inhalation of urban aerosols are usually lower than those from (210)Po intake by cigarette smokers and negligible in comparison to total natural radiation exposure. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modeling ozone uptake by urban and peri-urban forest: a case study in the Metropolitan City of Rome.

PubMed

Fusaro, Lina; Mereu, Simone; Salvatori, Elisabetta; Agliari, Elena; Fares, Silvano; Manes, Fausto

2018-03-01

Urban and peri-urban forests are green infrastructures (GI) that play a substantial role in delivering ecosystem services such as the amelioration of air quality by the removal of air pollutants, among which is ozone (O 3 ), which is the most harmful pollutant in Mediterranean metropolitan areas. Models may provide a reliable estimate of gas exchanges between vegetation and atmosphere and are thus a powerful tool to quantify and compare O 3 removal in different contexts. The present study modeled the O 3 stomatal uptake at canopy level of an urban and a peri-urban forest in the Metropolitan City of Rome in two different years. Results show different rates of O 3 fluxes between the two forests, due to different exposure to the pollutant, management practice effects on forest structure and functionality, and environmental conditions, namely, different stressors affecting the gas exchange rates of the two GIs. The periodic components of the time series calculated by means of the spectral analysis show that seasonal variation of modeled canopy transpiration is driven by precipitation in peri-urban forests, whereas in the urban forest seasonal variations are driven by vapor pressure deficit of ambient air. Moreover, in the urban forest high water availability during summer months, owing to irrigation practice, leads to an increase in O 3 uptake, thus suggesting that irrigation may enhance air phytoremediation in urban areas.

Gas and particle size distributions of polychlorinated naphthalenes in the atmosphere of Beijing, China.

PubMed

Zhu, Qingqing; Zhang, Xian; Dong, Shujun; Gao, Lirong; Liu, Guorui; Zheng, Minghui

2016-05-01

Polychlorinated naphthalenes (PCNs) were listed as persistent organic pollutants in the Stockholm Convention in 2015. Despite numerous studies on PCNs, little is known about their occurrence in atmospheric particulate matter of different sizes. In this study, 49 PCN congeners were investigated for their concentrations and size-specific distributions in an urban atmosphere, and preliminary exposure assessments were conducted. Ambient air samples were collected using a high-volume cascade impactor for division into a gas fraction and four particle size fractions. Samples were collected from October 2013 to June 2014 at an urban site in Beijing, China. The concentration range for PCNs in the atmosphere (gas + particle fractions) was 6.77-25.90 pg/m(3) (average 16.28 pg/m(3)). The particle-bound concentration range was 0.17-2.78 pg/m(3) (average 1.73 pg/m(3)). Therefore, PCNs were mainly found in the gas phase. The concentrations of PCNs in a fraction increased as the particle size decreased (dae > 10 μm, 10 μm ≥ dae > 2.5 μm, 2.5 μm ≥ dae > 1.0 μm and dae ≤ 1.0 μm). Consequently, PCNs were ubiquitous in inhalable fine particles, and the ΣPCNs associated with PM1.0 and PM2.5 reached 68.4% and 84.3%, respectively. Tetra-CNs and penta-CNs (the lower chlorinated homologues) predominated in the atmosphere. The homologue profiles in different size particles were almost similar, but the particulate profiles were different from those in the gas phase. Among the individual PCNs identified, CN38/40, CN52/60 and CN75 were the dominant compounds in the atmosphere. CN66/67 and CN73 collectively accounted for most of the total dioxin-like TEQ concentrations of the PCNs. Exposure to toxic compounds, such as PCNs present in PM1.0 or PM2.5, may affect human health. This work presents the first data on size-specific distributions of PCNs in the atmosphere. Copyright © 2016 Elsevier Ltd. All rights reserved.

In hindsight: urban exposure explains the association between prior migration and current health of older adults in Mexico.

PubMed

Wheaton, Felicia V; Crimmins, Eileen M

2013-04-01

This study examines sex differences in the association between migration and exposure to an urban environment and overweight, hypertension and diabetes in later life. Interviews were conducted with 3,604 adults aged 50 and older in the Mexican Family Life Survey (MxFLS). Logistic regression analyses were used to examine the association between previous migration, urban exposure, and risk of overweight, hypertension, and diabetes. Migration itself was not associated with health outcomes after controlling for urban exposure. The risk of overweight and diabetes associated with urban exposure appeared to be greater for men. Sex differences were found in the covariates that helped explain differences in health between those with high and low urban exposure. These findings underscore the need to consider heterogeneity in health by urban exposure and by sex.

Atmospheric carbon reduction by urban trees

Treesearch

David J. Nowak

1993-01-01

Trees, because they sequester atmospheric carbon through their growth process and conserve energy in urban areas, have been suggested as one means to combat increasing levels of atmospheric carbon. Analysis of the urban forest in Oakland, California (21% tree cover), reveals a tree carbon storage level of 11.0 metric tons/hectare. Trees in the area of the 1991 fire in...

Crossed optical and chemical evaluations of modern glass soiling in various European urban environments

NASA Astrophysics Data System (ADS)

Favez, Olivier; Cachier, Hélène; Chabas, Anne; Ausset, Patrick; Lefevre, Roger

As part of the MULTI-ASSESS and VIDRIO EC projects, the soiling of modern glass is characterised in various European urban atmospheres. Our original methodology relies on crossed chemical measurements of the deposit (evaluation of the ion, elemental and organic carbon contents, and subsequent "mass closure") and exhaustive measurements of glass optical properties (light reflectance, transmittance and absorption). Samples were exposed sheltered from rain in Athens, Krakow, London, Montelibretti (Italy), Prague and Troyes (France), during increasing exposure durations, up to more than two years. Although a slowing down of the deposition rate is observed for some species at some sites, no obvious saturation phenomenon seems to occur for the particle deposition. The chemical composition of the deposit is shown to reflect the atmospheric environment of the exposure site. Some post-deposit evolutions, such as the disappearance of ammonium and possibly of particulate organic matter, are found to occur. For thin deposits, the glass optical properties (e.g. light absorption and diffuse transmittance) are found to evolve quasi-linearly with species concentrations (EC and ions, respectively). However, for conditions creating heavier deposits such as long time exposures in rather polluted environments, a saturation phenomenon is observed. Using a simple model, light absorption, which is primarily due to EC particles, is shown to reach the saturation level ( S) for A≈16% and the concentration for which the semi-saturation level is reached (C 1/2) is found to be about 15 μgC of EC/cm 2. For diffuse transmittance, due to scattering species, these parameters are found to be about 30% and 65 μg of ions/cm 2, respectively. These values may be considered as representative of the soiling in Europe.

Urban aerosol particles of Santiago, Chile:. organic content and molecular characterization

NASA Astrophysics Data System (ADS)

Didyk, Borys M.; Simoneit, Bernd R. T.; Alvaro Pezoa, L.; Luis Riveros, M.; Anselmo Flores, A.

Santiago, Chile has developed a significant problem of atmospheric contamination with high levels of total suspended aerosol particles consisting of a high PM-10 fraction. This is associated with a growing economy, rapid urban expansion, increasing rate of motorization and expanding industrial activity. The organic contribution to atmospheric suspended particles (PM-10) in Santiago has been quantitated, characterized and related to its input sources in this report. The average organic content of 38% is significantly lower from pre-regulatory levels of 71% and in the range reported for other urban centers. Molecular markers indicate that a predominant proportion of the organic compounds associated with the particluate matter are derived from uncombusted diesel, uncombusted lubricating oil and other petrochemical fuel use. A significant organic contribution from natural plant wax hydrocarbons is also detected, suggesting biomass fuel use, open burning of vegetation in incidental fires or agricultural practices and resuspension of weathered vegetation debris. Aromatic hydrocarbon fractions indicate the presence of pyrogenic PAH formed by high-temperature combustion processes of petrochemical fuels with a significant contribution of retene indicative of conifer wood combustion. Maturity indicators, based on methylphenanthrene indexes, also indicate the simultaneous concurrence of high- and low-temperature combustion processes and confirm a significant contribution of non-petrochemical-sourced organic compounds to the atmospheric aerosols. Benzopyrene ratios indicate that Santiago aerosols are freshly generated and do not have an extensive solar exposure. The present study provides a reference baseline for the organic components relating to air quality in Santiago, and will permit the assessment of the environmental effectiveness of corrective measures related to energy usage and transport administration.

Traffic is a major source of atmospheric nanocluster aerosol

PubMed Central

Kuuluvainen, Heino; Karjalainen, Panu; Keskinen, Jorma; Hillamo, Risto; Niemi, Jarkko V.; Pirjola, Liisa; Timonen, Hilkka J.; Saarikoski, Sanna; Saukko, Erkka; Järvinen, Anssi; Silvennoinen, Henna; Rostedt, Antti; Olin, Miska; Yli-Ojanperä, Jaakko; Nousiainen, Pekka; Kousa, Anu; Dal Maso, Miikka

2017-01-01

In densely populated areas, traffic is a significant source of atmospheric aerosol particles. Owing to their small size and complicated chemical and physical characteristics, atmospheric particles resulting from traffic emissions pose a significant risk to human health and also contribute to anthropogenic forcing of climate. Previous research has established that vehicles directly emit primary aerosol particles and also contribute to secondary aerosol particle formation by emitting aerosol precursors. Here, we extend the urban atmospheric aerosol characterization to cover nanocluster aerosol (NCA) particles and show that a major fraction of particles emitted by road transportation are in a previously unmeasured size range of 1.3–3.0 nm. For instance, in a semiurban roadside environment, the NCA represented 20–54% of the total particle concentration in ambient air. The observed NCA concentrations varied significantly depending on the traffic rate and wind direction. The emission factors of NCA for traffic were 2.4·1015 (kgfuel)−1 in a roadside environment, 2.6·1015 (kgfuel)−1 in a street canyon, and 2.9·1015 (kgfuel)−1 in an on-road study throughout Europe. Interestingly, these emissions were not associated with all vehicles. In engine laboratory experiments, the emission factor of exhaust NCA varied from a relatively low value of 1.6·1012 (kgfuel)−1 to a high value of 4.3·1015 (kgfuel)−1. These NCA emissions directly affect particle concentrations and human exposure to nanosized aerosol in urban areas, and potentially may act as nanosized condensation nuclei for the condensation of atmospheric low-volatile organic compounds. PMID:28674021

Traffic is a major source of atmospheric nanocluster aerosol.

PubMed

Rönkkö, Topi; Kuuluvainen, Heino; Karjalainen, Panu; Keskinen, Jorma; Hillamo, Risto; Niemi, Jarkko V; Pirjola, Liisa; Timonen, Hilkka J; Saarikoski, Sanna; Saukko, Erkka; Järvinen, Anssi; Silvennoinen, Henna; Rostedt, Antti; Olin, Miska; Yli-Ojanperä, Jaakko; Nousiainen, Pekka; Kousa, Anu; Dal Maso, Miikka

2017-07-18

In densely populated areas, traffic is a significant source of atmospheric aerosol particles. Owing to their small size and complicated chemical and physical characteristics, atmospheric particles resulting from traffic emissions pose a significant risk to human health and also contribute to anthropogenic forcing of climate. Previous research has established that vehicles directly emit primary aerosol particles and also contribute to secondary aerosol particle formation by emitting aerosol precursors. Here, we extend the urban atmospheric aerosol characterization to cover nanocluster aerosol (NCA) particles and show that a major fraction of particles emitted by road transportation are in a previously unmeasured size range of 1.3-3.0 nm. For instance, in a semiurban roadside environment, the NCA represented 20-54% of the total particle concentration in ambient air. The observed NCA concentrations varied significantly depending on the traffic rate and wind direction. The emission factors of NCA for traffic were 2.4·10 15 (kg fuel ) -1 in a roadside environment, 2.6·10 15 (kg fuel ) -1 in a street canyon, and 2.9·10 15 (kg fuel ) -1 in an on-road study throughout Europe. Interestingly, these emissions were not associated with all vehicles. In engine laboratory experiments, the emission factor of exhaust NCA varied from a relatively low value of 1.6·10 12 (kg fuel ) -1 to a high value of 4.3·10 15 (kg fuel ) -1 These NCA emissions directly affect particle concentrations and human exposure to nanosized aerosol in urban areas, and potentially may act as nanosized condensation nuclei for the condensation of atmospheric low-volatile organic compounds.

Future research needs associated with the assessment of potential human health risks from exposure to toxic ambient air pollutants.

PubMed Central

Möller, L; Schuetzle, D; Autrup, H

1994-01-01

This paper presents key conclusions and future research needs from a Workshop on the Risk Assessment of Urban Air, Emissions, Exposure, Risk Identification, and Quantification, which was held in Stockholm during June 1992 by 41 participants from 13 countries. Research is recommended in the areas of identification and quantification of toxics in source emissions and ambient air, atmospheric transport and chemistry, exposure level assessment, the development of improved in vitro bioassays, biomarker development, the development of more accurate epidemiological methodologies, and risk quantification techniques. Studies are described that will be necessary to assess and reduce the level of uncertainties associated with each step of the risk assessment process. International collaborative research efforts between industry and government organizations are recommended as the most effective way to carry out this research. PMID:7529703

Major sources of benzene exposure.

PubMed Central

Wallace, L A

1989-01-01

Data from EPA's TEAM Study allow us to identify the major sources of exposure to benzene for much of the U.S. population. These sources turn out to be quite different from what had previously been considered the important sources. The most important source of exposure for 50 million smokers is the mainstream smoke from their cigarettes, which accounts for about half of the total population burden of exposure to benzene. Another 20% of nationwide exposure is contributed by various personal activities, such as driving and using attached garages. (Emissions from consumer products, building materials, paints, and adhesives may also be important, although data are largely lacking.) The traditional sources of atmospheric emissions (auto exhaust and industrial emissions) account for only about 20% of total exposure. Environmental tobacco smoke is an important source, accounting for about 5% of total nationwide exposure. A number of sources sometimes considered important, such as petroleum refining operations, petrochemical manufacturing, oil storage tanks, urban-industrial areas, service stations, certain foods, groundwater contamination, and underground gasoline leaks, appear to be unimportant on a nationwide basis. PMID:2477239

Estimating the influence of different urban canopy cover types on atmospheric particulate matter (PM10) pollution abatement in London UK.

NASA Astrophysics Data System (ADS)

Tallis, Matthew; Freer-Smith, Peter; Sinnett, Danielle; Aylott, Matthew; Taylor, Gail

2010-05-01

In the urban environment atmospheric pollution by PM10 (particulate matter with a diameter less than 10 x 10-6 m) is a problem that can have adverse effects on human health, particularly increasing rates of respiratory disease. The main contributors to atmospheric PM10 in the urban environment are road traffic, industry and power production. The urban tree canopy is a receptor for removing PM10s from the atmosphere due to the large surface areas generated by leaves and air turbulence created by the structure of the urban forest. In this context urban greening has long been known as a mechanism to contribute towards PM10 removal from the air, furthermore, tree canopy cover has a role in contributing towards a more sustainable urban environment. The work reported here has been carried out within the BRIDGE project (SustainaBle uRban plannIng Decision support accountinG for urban mEtabolism). The aim of this project is to assess the fluxes of energy, water, carbon dioxide and particulates within the urban environment and develope a DSS (Decision Support System) to aid urban planners in sustainable development. A combination of published urban canopy cover data from ground, airborne and satellite based surveys was used. For each of the 33 London boroughs the urban canopy was classified to three groups, urban woodland, street trees and garden trees and each group quantified in terms of ground cover. The total [PM10] for each borough was taken from the LAEI (London Atmospheric Emissions Inventory 2006) and the contribution to reducing [PM10] was assessed for each canopy type. Deposition to the urban canopy was assessed using the UFORE (Urban Forest Effects Model) approach. Deposition to the canopy, boundary layer height and percentage reduction of the [PM10] in the atmosphere was assessed using both hourly meterological data and [PM10] and seasonal data derived from annual models. Results from hourly and annual data were compared with measured values. The model was then applied to future predictions of annual [PM10] and future canopy cover scenarios for London. The contribution of each canopy type subjected to the different atmospheric [PM10] of the 33 London boroughs now and in the future will be discussed. Implementing these findings into a decision support system (DSS) for sustainable urban planning will also be discussed.

Modelling Short-Term Maximum Individual Exposure from Airborne Hazardous Releases in Urban Environments. Part ΙI: Validation of a Deterministic Model with Wind Tunnel Experimental Data.

PubMed

Efthimiou, George C; Bartzis, John G; Berbekar, Eva; Hertwig, Denise; Harms, Frank; Leitl, Bernd

2015-06-26

The capability to predict short-term maximum individual exposure is very important for several applications including, for example, deliberate/accidental release of hazardous substances, odour fluctuations or material flammability level exceedance. Recently, authors have proposed a simple approach relating maximum individual exposure to parameters such as the fluctuation intensity and the concentration integral time scale. In the first part of this study (Part I), the methodology was validated against field measurements, which are governed by the natural variability of atmospheric boundary conditions. In Part II of this study, an in-depth validation of the approach is performed using reference data recorded under truly stationary and well documented flow conditions. For this reason, a boundary-layer wind-tunnel experiment was used. The experimental dataset includes 196 time-resolved concentration measurements which detect the dispersion from a continuous point source within an urban model of semi-idealized complexity. The data analysis allowed the improvement of an important model parameter. The model performed very well in predicting the maximum individual exposure, presenting a factor of two of observations equal to 95%. For large time intervals, an exponential correction term has been introduced in the model based on the experimental observations. The new model is capable of predicting all time intervals giving an overall factor of two of observations equal to 100%.

Comparing the diurnal and seasonal variabilities of atmospheric and surface urban heat islandsbased on the Beijing urban meteorological network

NASA Astrophysics Data System (ADS)

Jiang, S.; Wang, K.; Wang, J.; Zhou, C.; Wang, X.; Lee, X.

2017-12-01

This study compared the diurnal and seasonal cycles of atmospheric and surface urban heat islands (UHIs) based on hourly air temperatures (Ta) collected at 65 out of 262 stations in Beijing and land surface temperature (Ts) derived from Moderate Resolution Imaging Spectroradiometer in the years 2013-2014. We found that the nighttime atmospheric and surface UHIs referenced to rural cropland stations exhibited significant seasonal cycles, with the highest in winter. However, the seasonal variations in the nighttime UHIs referenced to mountainous forest stations were negligible, because mountainous forests have a higher nighttime Ts in winter and a lower nighttime T a in summer than rural croplands. Daytime surface UHIs showed strong seasonal cycles, with the highest in summer. The daytime atmospheric UHIs exhibited a similar but less seasonal cycle under clear-sky conditions, which was not apparent under cloudy-sky conditions. Atmospheric UHIs in urban parks were higher in daytime. Nighttime atmospheric UHIs are influenced by energy stored in urban materials during daytime and released during nighttime. The stronger anthropogenic heat release in winter causes atmospheric UHIs to increase with time during winter nights, but decrease with time during summer nights. The percentage of impervious surfaces is responsible for 49%-54% of the nighttime atmospheric UHI variability and 31%-38% of the daytime surface UHI variability. However, the nighttime surface UHI was nearly uncorrelated with the percentage of impervious surfaces around the urban stations.

Investigation of levels in ambient air near sources of Polychlorinated Biphenyls (PCBs) in Kanpur, India, and risk assessment due to inhalation.

PubMed

Goel, Anubha; Upadhyay, Kritika; Chakraborty, Mrinmoy

2016-05-01

Polychlorinated biphenyls (PCBs) are a class of organic compounds listed as persistent organic pollutant and have been banned for use under Stockholm Convention (1972). They were used primarily in transformers and capacitors, paint, flame retardants, plasticizers, and lubricants. PCBs can be emitted through the primary and secondary sources into the atmosphere, undergo long-range atmospheric transport, and hence have been detected worldwide. Reported levels in ambient air are generally higher in urban areas. Active sampling of ambient air was conducted in Kanpur, a densely populated and industrialized city in the Indo-Gangetic Plain, for detection of 32 priority PCBs, with the aim to determine the concentration in gas/particle phase and assess exposure risk. More than 50 % of PCBs were detected in air. Occurrence in particles was dominated by heavier congeners, and levels in gas phase were below detection. Levels determined in this study are lower than the levels in Coastal areas of India but are at par with other Asian countries where majority of sites chosen for sampling were urban industrial areas. Human health risk estimates through air inhalation pathway were made in terms of lifetime average daily dose (LADD) and incremental lifetime cancer risks (ILCR). The study found lower concentrations of PCBs than guideline values and low health risk estimates through inhalation within acceptable levels, indicating a minimum risk to the adults due to exposure to PCBs present in ambient air in Kanpur.

The Urban Dust Dome: A Demonstration Model

ERIC Educational Resources Information Center

Cross, Ralph D.

1973-01-01

Working plans for an inexpensive urban dust dome model are presented together with some generalizations about urban atmosphere pollution. Theories and principles of atmospheric pollution which are introduced can be made meaningful to elementary students through classroom use of this model. (SM)

Effects of the Urban Heat Island on Aerosol pH

NASA Astrophysics Data System (ADS)

Battaglia, M., Jr.; Douglas, S.; Hennigan, C. J.

2017-12-01

The urban heat island (UHI) is a widely observed phenomenon whereby urban environments have higher temperature (T) and lower relative humidity (RH) than surrounding suburban and rural areas. Both of these factors affect the partitioning of semi-volatile species found in the atmosphere, such as nitric acid and ammonia. These species are inherently tied to aerosol pH, which is a key parameter driving some atmospheric chemical processes and environmental effects of aerosols. In this study, we characterized the effect of the UHI on aerosol pH in Baltimore, MD and Chicago, IL. These cities were selected based on differences in climatology, source influences, and atmospheric composition. Meteorological and atmospheric composition data from the urban centers and surrounding rural locations were used as inputs to the ISORROPIA-II aerosol thermodynamic model to compute gas/particle partitioning, aerosol liquid water content, and aerosol pH. Dramatic differences in aerosol liquid water (ALW) content were found in both cities and were attributable to the T and RH differences (UHI effect). The urban-rural differences in ALW result in urban aerosol pH that is systematically lower (more acidic) than rural aerosol pH for identical atmospheric composition. The UHI in Baltimore is most intense during the summer and at night, with differences of up to 1 pH unit predicted during these times. Similarly, the UHI in Chicago is most intense during the summer and at night; however, the atmospheric composition in Chicago shows a mediating effect, with differences of up to 0.65 pH units predicted during these times. These results are likely to have broad implications for chemistry occurring in and around urban atmospheres globally, although the magnitude of the effect may differ based on the UHI characteristic of each urban environment.

Exposure of coastal built assets in the South Pacific to climate risks

NASA Astrophysics Data System (ADS)

Kumar, Lalit; Taylor, Subhashni

2015-11-01

Pacific island countries (PICs) are situated in a highly dynamic ocean-atmosphere interface, are dispersed over a large ocean area, and have highly populated urban centres located on the coastal margin. The built infrastructure associated with urban centres is also located within close proximity to the coastlines, exposing such infrastructure to a variety of natural and climate change-related hazards. In this research we undertake a comprehensive analysis of the exposure of built infrastructure assets to climate risk for 12 PICs. We show that 57% of the assessed built infrastructure for the 12 PICs is located within 500 m of their coastlines, amounting to a total replacement value of US$21.9 billion. Eight of the 12 PICs have 50% or more of their built infrastructure located within 500 m of their coastlines. In particular, Kiribati, Marshall Islands and Tuvalu have over 95% of their built infrastructure located within 500 m of their coastlines. Coastal adaptation costs will require substantial financial resources, which may not be available in developing countries such as the PICs, leaving them to face very high impacts but lacking the adaptive capacity.

Benzo[a]pyrene in urban environments of eastern Moscow: pollution levels and critical loads

NASA Astrophysics Data System (ADS)

Kasimov, Nikolay S.; Kosheleva, Natalia E.; Nikiforova, Elena M.; Vlasov, Dmitry V.

2017-02-01

Polycyclic aromatic hydrocarbons (PAHs), particularly benzo[a]pyrene (BaP), are toxic compounds emitted from various anthropogenic sources. Understanding the BaP concentrations, dynamics and decomposition in soil is required to assess the critical loads of BaP in urban environments. This study is the first attempt to evaluate all major input and output components of benzo[a]pyrene (BaP) balance and to calculate the permissible load on the urban environment in different land-use zones in the Eastern district of Moscow. BaP contamination of the snow cover in the Eastern district of Moscow was related to daily BaP fallout from the atmosphere. In 2010, the mean content of the pollutant in the snow dust was 1942 ng g-1, whereas the average intensity of its fallout was 7.13 ng m-2 per day. Across the territory, BaP winter fallout intensities varied from 0.3 to 1100 ng m-2 per day. The average BaP content in the surface (0-10 cm) soil horizons was 409 ng g-1, which is 83 times higher than the local background value and 20 times higher than the maximum permissible concentration (MPC) accepted in Russia. The variations in soil and snow BaP concentrations among different land-use zones were examined. A significant contribution of BaP from the atmosphere to urban soils was identified. Based on the measurements of BaP atmospheric fallout and BaP reserves in the soils, the critical loads of BaP for the land-use zones in the Eastern district were calculated for different values of degradation intensity and different exposure times. It was established that at an annual degradation intensity of 1-10 %, ecologically safe BaP levels in the soils of all land-use zones, excluding the agricultural zone, will only be reached after many decades or centuries.

Atmospheric Inputs of Nitrogen, Carbon, and Phosphorus across an Urban Area: Unaccounted Fluxes and Canopy Influences

NASA Astrophysics Data System (ADS)

Decina, Stephen M.; Templer, Pamela H.; Hutyra, Lucy R.

2018-02-01

Rates of atmospheric deposition are declining across the United States, yet urban areas remain hotspots of atmospheric deposition. While past studies show elevated rates of inorganic nitrogen (N) deposition in cities, less is known about atmospheric inputs of organic N, organic carbon (C), and organic and inorganic phosphorus (P), all of which can affect ecosystem processes, water quality, and air quality. Further, the effect of the tree canopy on amounts and forms of nutrients reaching urban ground surfaces is not well-characterized. We measured growing season rates of total N, organic C, and total P in bulk atmospheric inputs, throughfall, and soil solution around the greater Boston area. We found that organic N constitutes a third of total N inputs, organic C inputs are comparable to rural inputs, and inorganic P inputs are 1.2 times higher than those in sewage effluent. Atmospheric inputs are enhanced two-to-eight times in late spring and are elevated beneath tree canopies, suggesting that trees augment atmospheric inputs to ground surfaces. Additionally, throughfall inputs may directly enter runoff when trees extend above impervious surfaces, as is the case with 26.1% of Boston's tree canopy. Our results indicate that the urban atmosphere is a significant source of elemental inputs that may impact urban ecosystems and efforts to improve water quality, particularly in terms of P. Further, as cities create policies encouraging tree planting to provide ecosystem services, locating trees above permeable surfaces to reduce runoff nutrient loads may be essential to managing urban biogeochemical cycling and water quality.

Urban atmospheres

PubMed Central

Gandy, Matthew

2017-01-01

What is an urban atmosphere? How can we differentiate an ‘atmosphere’ from other facets of urban consciousness and experience? This essay explores some of the wider cultural, political, and philosophical connotations of atmospheres as a focal point for critical reflections on space and subjectivity. The idea of an ‘affective atmosphere’ as a distinctive kind of mood or shared corporeal phenomenon is considered in relation to recent developments in phenomenology, extended conceptions of agency, and new understandings of materialism. The essay draws in particular on the changing characteristics of air and light to reflect on different forms of sensory experience and their wider cultural and political connotations. The argument highlights some of the tensions and anomalies that permeate contemporary understandings of urban atmospheres. PMID:29278257

Effects of atmospheric stability and urban morphology on daytime intra-urban temperature variability for Glasgow, UK.

PubMed

Drach, Patricia; Krüger, Eduardo L; Emmanuel, Rohinton

2018-06-15

This study investigates the joint effect of atmospheric conditions and urban morphology, expressed as the Sky View Factor (SVF), on intra-urban variability. The study has been carried out in Glasgow, UK, a shrinking city with a maritime temperate climate type, and findings could guide future climate adaptation plans in terms of morphology and services provided by the municipality to overcome thermal discomfort in outdoor settings. In this case, SVF has been used as an indicator of urban morphology. The modified Pasquill-Gifford-Turner (PGT) classification system was adopted for classifying the temperature monitoring periods according to atmospheric stability conditions. Thirty two locations were selected on the basis of SVF with a wide variety of urban shapes (narrow streets, neighbourhood green spaces, urban parks, street canyons and public squares) and compared to a reference weather station during a total of twenty three transects during late spring and summer in 2013. Maximum daytime intra-urban temperature differences were found to be strongly correlated with atmospheric stability classes. Furthermore, differences in air temperature are noticeable in urban canyons, with a direct correlation to the site's SVF (or sky openness) and with an inverse trend under open-air conditions. Copyright © 2018 Elsevier B.V. All rights reserved.

Air pollution impacts on avian species via inhalation exposure and associated outcomes

NASA Astrophysics Data System (ADS)

Sanderfoot, Olivia V.; Holloway, Tracey

2017-08-01

Despite the well-established links between air pollution and human health, vegetation, and aquatic ecosystems, less attention has been paid to the potential impact of reactive atmospheric gases and aerosols on avian species. In this literature review, we summarize findings published since 1950 regarding avian responses to air pollution and discuss knowledge gaps that could be addressed in future studies. We find consistent evidence for adverse health impacts on birds attributable to exposure to gas-phase and particulate air pollutants, including carbon monoxide (CO), ozone (O3), sulfur dioxide (SO2), smoke, and heavy metals, as well as mixtures of urban and industrial emissions. Avian responses to air pollution include respiratory distress and illness, increased detoxification effort, elevated stress levels, immunosuppression, behavioral changes, and impaired reproductive success. Exposure to air pollution may furthermore reduce population density, species diversity, and species richness in bird communities.

Atmospheric nitrate export in streams along a montane to urban gradient.

PubMed

Bourgeois, Ilann; Savarino, Joel; Némery, Julien; Caillon, Nicolas; Albertin, Sarah; Delbart, Franck; Voisin, Didier; Clément, Jean-Christophe

2018-08-15

Nitrogen (N) emissions associated with urbanization exacerbate the atmospheric N influx to remote ecosystems - like mountains -, leading to well-documented detrimental effects on ecosystems (e.g., soil acidification, pollution of freshwaters). Here, the importance and fate of N deposition in a watershed was evaluated along a montane to urban gradient, using a multi-isotopic tracers approach (Δ 17 O, δ 15 N, δ 18 O of nitrate, δ 2 H and δ 18 O of water). In this setting, the montane streams had higher proportions of atmospheric nitrate compared to urban streams, and exported more atmospheric nitrate on a yearly basis (0.35 vs 0.10 kg-Nha -1 yr -1 ). In urban areas, nitrate exports were driven by groundwater, whereas in the catchment head nitrate exports were dominated by surface runoff. The main sources of nitrate to the montane streams were microbial nitrification and atmospheric deposition, whereas microbial nitrification and sewage leakage contributed most to urban streams. Based on the measurement of δ 15 N and δ 18 O-NO 3 - , biological processes such as denitrification or N assimilation were not predominant in any streams in this study. The observed low δ 15 N and δ 18 O range of terrestrial nitrate (i.e., nitrate not coming from atmospheric deposition) in surface water compared to literature suggests that atmospheric deposition may be underestimated as a direct source of N. Copyright © 2018 Elsevier B.V. All rights reserved.

[Quantitative estimation source of urban atmospheric CO2 by carbon isotope composition].

PubMed

Liu, Wei; Wei, Nan-Nan; Wang, Guang-Hua; Yao, Jian; Zeng, You-Shi; Fan, Xue-Bo; Geng, Yan-Hong; Li, Yan

2012-04-01

To effectively reduce urban carbon emissions and verify the effectiveness of currently project for urban carbon emission reduction, quantitative estimation sources of urban atmospheric CO2 correctly is necessary. Since little fractionation of carbon isotope exists in the transportation from pollution sources to the receptor, the carbon isotope composition can be used for source apportionment. In the present study, a method was established to quantitatively estimate the source of urban atmospheric CO2 by the carbon isotope composition. Both diurnal and height variations of concentrations of CO2 derived from biomass, vehicle exhaust and coal burning were further determined for atmospheric CO2 in Jiading district of Shanghai. Biomass-derived CO2 accounts for the largest portion of atmospheric CO2. The concentrations of CO2 derived from the coal burning are larger in the night-time (00:00, 04:00 and 20:00) than in the daytime (08:00, 12:00 and 16:00), and increase with the increase of height. Those derived from the vehicle exhaust decrease with the height increase. The diurnal and height variations of sources reflect the emission and transport characteristics of atmospheric CO2 in Jiading district of Shanghai.

Role of Automobile Exhaust on the Photoreductive Solubilization of Atmospheric Iron

NASA Astrophysics Data System (ADS)

Haynes, J.; Majestic, B. J.; Cutler, E.

2016-12-01

Atmospheric iron (Fe) plays an essential role in the carbon cycle, affecting the Earth's energy balance and human health. Fe catalyzes oxidations of organic carbon species and serves as a limiting nutrient for phytoplankton in about half of the world's oceans. Wind-blown dust is the major source of atmospheric insoluble Fe while urban areas are correlated with relatively high percentages of soluble Fe. The occurrence of elevated levels of soluble Fe near urban and industrial regions suggests a correlation between Fe solubilization and organic combustion products, including polycyclic aromatic hydrocarbons (PAH). Fossil fuel consumption for internal combustion engines produce atmospheric PAH as a major component of automobile exhaust. Under light, PAH transform into oxidized components such as ketones and carboxylic acids. For example, phthalic acid (formed from naphthalene) inhibits Fe oxidation reactions and therefore may contribute to Fe reduction and increased solubility. The wind-blown dust and PAH-containing combustion products undergo long-range atmospheric transport leading to mixing and metal-organic interactions. The current study focuses on how a saturated PAH suspension affects the production of soluble Fe. Reactions of soil-based Fe and saturated solutions of PAH are performed under controlled conditions simulating natural sunlight. Samples are analyzed by ICPMS for soluble Fe before and after solar exposure reactions; soluble Fe is separated from total Fe by filtration and total Fe by acid-assisted microwave digestion. Data indicate an increase in Fe solubility (1.2% to 4.2%) in the presence of PAH, as compared to soil in water alone, and an even greater increase in Fe solubility (4.2% to 8.4%) when exposed to solar radiation. Research is ongoing to determine the dependence of oxidized PAH on kinetic and overall Fe solubility.

Local source impacts on primary and secondary aerosols in the Midwestern United States

NASA Astrophysics Data System (ADS)

Jayarathne, Thilina; Rathnayake, Chathurika M.; Stone, Elizabeth A.

2016-04-01

Atmospheric particulate matter (PM) exhibits heterogeneity in composition across urban areas, leading to poor representation of outdoor air pollutants in human exposure assessments. To examine heterogeneity in PM composition and sources across an urban area, fine particulate matter samples (PM2.5) were chemically profiled in Iowa City, IA from 25 August to 10 November 2011 at two monitoring stations. The urban site is the federal reference monitoring (FRM) station in the city center and the peri-urban site is located 8.0 km to the west on the city edge. Measurements of PM2.5 carbonaceous aerosol, inorganic ions, molecular markers for primary sources, and secondary organic aerosol (SOA) tracers were used to assess statistical differences in composition and sources across the two sites. PM2.5 mass ranged from 3 to 26 μg m-3 during this period, averaging 11.2 ± 4.9 μg m-3 (n = 71). Major components of PM2.5 at the urban site included organic carbon (OC; 22%), ammonium (14%), sulfate (13%), nitrate (7%), calcium (2.9%), and elemental carbon (EC; 2.2%). Periods of elevated PM were driven by increases in ammonium, sulfate, and SOA tracers that coincided with hot and dry conditions and southerly winds. Chemical mass balance (CMB) modeling was used to apportion OC to primary sources; biomass burning, vegetative detritus, diesel engines, and gasoline engines accounted for 28% of OC at the urban site and 24% of OC at the peri-urban site. Secondary organic carbon from isoprene and monoterpene SOA accounted for an additional 13% and 6% of OC at the urban and peri-urban sites, respectively. Differences in biogenic SOA across the two sites were associated with enhanced combustion activities in the urban area and higher aerosol acidity at the urban site. Major PM constituents (e.g., OC, ammonium, sulfate) were generally well-represented by a single monitoring station, indicating a regional source influence. Meanwhile, nitrate, biomass burning, food cooking, suspended dust, and biogenic SOA were not well-represented by a single site and demonstrated local influences. For isoprene SOA, product distributions indicated a larger role for the high-NOx pathway at the urban site. These local sources are largely responsible for differences in population exposures to outdoor PM in the study domain located within the Midwestern US.

ATMOSPHERIC DRY PARTICLE DEPOSITION OF POPS AND TRACE METALS IN AN URBAN- AND INDUSTRIALLY-IMPACTED MID-ATLANTIC ESTUARY (AEOLOS B MID-ATLANTIC)

EPA Science Inventory

Emissions of hazardous air pollutants into the coastal urban-industrial atmosphere increase atmospheric depositional fluxes to proximate water bodies. Dry deposition of large particles containing persistent organic pollutants (POPs) and trace metals were a major contribu...

Particle size distribution and perchlorate levels in settled dust from urban roads, parks, and roofs in Chengdu, China.

PubMed

Li, Yiwen; Shen, Yang; Pi, Lu; Hu, Wenli; Chen, Mengqin; Luo, Yan; Li, Zhi; Su, Shijun; Ding, Sanglan; Gan, Zhiwei

2016-01-01

A total of 27 settled dust samples were collected from urban roads, parks, and roofs in Chengdu, China to investigate particle size distribution and perchlorate levels in different size fractions. Briefly, fine particle size fractions (<250 μm) were the dominant composition in the settled dust samples, with mean percentages of 80.2%, 69.5%, and 77.2% for the urban roads, roofs, and the parks, respectively. Perchlorate was detected in all of the size-fractionated dust samples, with concentrations ranging from 73.0 to 6160 ng g(-1), and the median perchlorate levels increased with decreasing particle size. The perchlorate level in the finest fraction (<63 μm) was significantly higher than those in the coarser fractions. To our knowledge, this is the first report on perchlorate concentrations in different particle size fractions. The calculated perchlorate loadings revealed that perchlorate was mainly associated with finer particles (<125 μm). An exposure assessment indicated that exposure to perchlorate via settled road dust intake is safe to both children and adults in Chengdu, China. However, due to perchlorate mainly existing in fine particles, there is a potential for perchlorate to transfer into surface water and the atmosphere by runoff and wind erosion or traffic emission, and this could act as an important perchlorate pollution source for the indoor environment, and merits further study.

Impact of Extensive Urbanization on Summertime Rainfall in the Beijing Region and the Role of Local Precipitation Recycling

NASA Astrophysics Data System (ADS)

Wang, Jun; Feng, Jinming; Yan, Zhongwei

2018-04-01

In this study, we conducted nested high-resolution simulations using the Weather Research and Forecasting model coupled with a single-layer urban canopy model to investigate the impact of extensive urbanization on regional precipitation over the Beijing-Tianjin-Hebei region in China. The results showed that extensive urbanization decreased precipitation considerably over and downwind of Beijing city. The prevalence of impermeable urban land inhibits local evaporation that feeds moisture into the overlying atmosphere, decreasing relative humidity and atmospheric instability. The dynamic precipitation recycling model was employed to estimate the precipitation that originates from local surface evaporation and large-scale advection of moisture. Results showed that about 11% of the urbanization-induced decrease in total precipitation over the Greater Beijing Region and its surroundings was contributed by the decrease in local recycled precipitation, while the other part (89%) was due to decreasing large-scale advected precipitation. Results suggest that the low evaporation from urban land surfaces not only reduces the supply of water vapor for local recycled precipitation directly but also decreases the convective available potential energy and hence the conversion efficiency of atmospheric moisture into rainfall. The urbanization-induced variations in local recycled precipitation were found to be correlated with the net atmospheric moisture flux on a monthly time scale.

Posttranslational modification of bioaerosol protein by common gas pollutants: NO2 and O3

NASA Astrophysics Data System (ADS)

Abdullahi Mahmood, Marliyyah; Bloss, William; Pope, Francis

2016-04-01

Air pollution can exacerbate several medical conditions, for example, hay fever and asthma. The global incidence of hay fever has been rising for decades; however, the underlying reasons behind this rise remain unclear. It is hypothesized that the exposure of pollen to common gas phase pollutants, such as nitrogen dioxide (NO2) and ozone (O3), increases the allergenicity of the pollen and thus increases hay fever incidence (Reinmuth-Selzle et al., 2014, Franze, et al., 2005). Since atmospheric pollutants often have greater concentrations within urban areas (in particular NO2) the hypothesis suggests that greater allergenicity should occur in urban areas. Certainly, several studies do suggest higher hay fever incidence within urban areas compared to rural areas (Schröder et al., 2015). Previous published work suggests a link between increased allergies and changes in the chemical composition of pollen protein via posttranslational modification of the protein (Reinmuth-Selzle et al., 2014). This study investigates the posttranslational modification of two highly allergenic pollen species (Birch and Ragweed) that are common in Europe. Within the laboratory, we expose pollen grains to atmospherically relevant exposures of gas phase NO2, O3 and other common gas phase oxidants under a range of environmentally relevant conditions. The effects of the exposures on the biochemistry of the pollen grains were probed using a proteomic approach (liquid chromatography coupled ultra-high resolution spectrometer). Our findings indicate the interaction between gas phase pollutants and pollen cause protein specific modifications; in particular nitration that occurs upon tyrosine residues and nitrosylation on cysteine residues. These modifications may affect human immune response to the pollen protein, which may suggest a possible reason for increased allergies in reaction to such chemically altered protein. Quantification of the relative degree of PTMs, from a variety of methodologies, will also be presented. Laboratory-derived results will be supported with a time series analysis of hay fever incidence rates, which will take into account both the pollen count, and pollutant concentrations. References Franze, Thomas, et al. "Protein nitration by polluted air." Environmental science & technology 39.6 (2005): 1673-1678. Reinmuth-Selzle, Kathrin, et al. "Nitration of the Birch Pollen Allergen Bet v 1.0101: Efficiency and Site-Selectivity of Liquid and Gaseous Nitrating Agents." Journal of proteome research 13.3 (2014): 1570-1577. Schröder, Paul C., et al. "The rural-urban enigma of allergy: What can we learn from studies around the world?." Pediatric Allergy and Immunology 26.2 (2015): 95-102.

On the temporal variation of leaf magnetic parameters: seasonal accumulation of leaf-deposited and leaf-encapsulated particles of a roadside tree crown.

PubMed

Hofman, Jelle; Wuyts, Karen; Van Wittenberghe, Shari; Samson, Roeland

2014-09-15

Understanding the accumulation behaviour of atmospheric particles inside tree leaves is of great importance for the interpretation of biomagnetic monitoring results. In this study, we evaluated the temporal variation of the saturation isothermal remanent magnetisation (SIRM) of leaves of a roadside urban Platanus × acerifolia Willd. tree in Antwerp, Belgium. We hereby examined the seasonal development of the total leaf SIRM signal as well as the leaf-encapsulated fraction of the deposited dust, by washing the leaves before biomagnetic analysis. On average 38% of the leaf SIRM signal was exhibited by the leaf-encapsulated particles. Significant correlations were found between the SIRM and the cumulative daily average atmospheric PM10 and PM2.5 measurements. Moreover, a steady increase of the SIRM throughout the in-leaf season was observed endorsing the applicability of biomagnetic monitoring as a proxy for the time-integrated PM exposure of urban tree leaves. Strongest correlations were obtained for the SIRM of the leaf-encapsulated particles which confirms the dynamic nature of the leaf surface-accumulated particles. Copyright © 2014 Elsevier B.V. All rights reserved.

Spatial and temporal variation, source profile, and formation mechanisms of PCDD/FS in the atmosphere of an e-waste recycling area, south China.

PubMed

Xiao, Xiao; Hu, Jianfang; Chen, Pei; Chen, Deyi; Huang, Weilin; Peng, Ping'an; Ren, Man

2014-03-01

The present study investigated the impact of typical electronic waste (e-waste) dismantling activities on the distribution of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the adjacent atmospheric environment. The target areas included the town of Longtang, a well known e-waste recycling site, and 2 affected neighborhoods, all of which were within the city of Qingyuan,Guangdong Province, China. Air samples were collected from the 3 locations and analyzed following the standard methods. The results showed that the atmospheric PCDD/F level in Longtang was 159.41 pg m(-3), which was approximately 16 to 17 times higher than its neighborhoods and 2 to 4 orders of magnitude higher than baseline levels reported for urban cities of the world. The homologue profiles were quite different from the typical urban air patterns, as de novo synthesis was likely to be the dominant formation pathway of the detected PCDD/Fs. The seasonal variations were minor, and the concentration change of PCDD/Fs between day and night did not follow a clear pattern. Given the unique atmospheric PCDD/F concentrations, similar homologue profiles, and the elemental carbon/organic carbon relationships of the 3 sampling sites, the relatively high dioxin levels in its 2 neighborhoods were most likely the result of the primitive e-waste dismantling activities undertaken in the town of Longtang. A simple risk assessment also showed that the residents of Qingyuan were at high risk of exposure to PCDD/Fs.

Mortality and emergency hospitalizations associated with atmospheric particulate matter episodes across the UK in spring 2014.

PubMed

Macintyre, Helen L; Heaviside, Clare; Neal, Lucy S; Agnew, Paul; Thornes, John; Vardoulakis, Sotiris

2016-12-01

Exposure to particulate air pollution is known to have negative impacts on human health. Long-term exposure to anthropogenic particulate matter is associated with the equivalent of around 29,000 deaths a year in the UK. However, short-lived air pollution episodes on the order of a few days are also associated with increased daily mortality and emergency hospital admissions for respiratory and cardiovascular conditions. The UK experienced widespread high levels of particulate air pollution in March-April 2014; observations of hourly mean PM 2.5 concentrations reached up to 83μgm -3 at urban background sites. We performed an exposure and health impact assessment of the spring air pollution, focusing on two episodes with the highest concentrations of PM 2.5 (12-14 March and 28 March-3 April 2014). Across these two episodes of elevated air pollution, totalling 10days, around 600 deaths were brought forward from short-term exposure to PM 2.5 , representing 3.9% of total all-cause (excluding external) mortality during these days. Using observed levels of PM 2.5 from other years, we estimate that this is 2.0 to 2.7 times the mortality burden associated with typical urban background levels of PM 2.5 at this time of year. Our results highlight the potential public health impacts and may aid planning for health care resources when such an episode is forecast. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Heat and Humidity in the City: Neighborhood Heat Index Variability in a Mid-Sized City in the Southeastern United States

PubMed Central

Hass, Alisa L.; Ellis, Kelsey N.; Reyes Mason, Lisa; Hathaway, Jon M.; Howe, David A.

2016-01-01

Daily weather conditions for an entire city are usually represented by a single weather station, often located at a nearby airport. This resolution of atmospheric data fails to recognize the microscale climatic variability associated with land use decisions across and within urban neighborhoods. This study uses heat index, a measure of the combined effects of temperature and humidity, to assess the variability of heat exposure from ten weather stations across four urban neighborhoods and two control locations (downtown and in a nearby nature center) in Knoxville, Tennessee, USA. Results suggest that trees may negate a portion of excess urban heat, but are also associated with greater humidity. As a result, the heat index of locations with more trees is significantly higher than downtown and areas with fewer trees. Trees may also reduce heat stress by shading individuals from incoming radiation, though this is not considered in this study. Greater amounts of impervious surfaces correspond with reduced evapotranspiration and greater runoff, in terms of overall mass balance, leading to a higher temperature, but lower relative humidity. Heat index and relative humidity were found to significantly vary between locations with different tree cover and neighborhood characteristics for the full study time period as well as for the top 10% of heat index days. This work demonstrates the need for high-resolution climate data and the use of additional measures beyond temperature to understand urban neighborhood exposure to extreme heat, and expresses the importance of considering vulnerability differences among residents when analyzing neighborhood-scale impacts. PMID:26761021

Heat and Humidity in the City: Neighborhood Heat Index Variability in a Mid-Sized City in the Southeastern United States.

PubMed

Hass, Alisa L; Ellis, Kelsey N; Reyes Mason, Lisa; Hathaway, Jon M; Howe, David A

2016-01-11

Daily weather conditions for an entire city are usually represented by a single weather station, often located at a nearby airport. This resolution of atmospheric data fails to recognize the microscale climatic variability associated with land use decisions across and within urban neighborhoods. This study uses heat index, a measure of the combined effects of temperature and humidity, to assess the variability of heat exposure from ten weather stations across four urban neighborhoods and two control locations (downtown and in a nearby nature center) in Knoxville, Tennessee, USA. Results suggest that trees may negate a portion of excess urban heat, but are also associated with greater humidity. As a result, the heat index of locations with more trees is significantly higher than downtown and areas with fewer trees. Trees may also reduce heat stress by shading individuals from incoming radiation, though this is not considered in this study. Greater amounts of impervious surfaces correspond with reduced evapotranspiration and greater runoff, in terms of overall mass balance, leading to a higher temperature, but lower relative humidity. Heat index and relative humidity were found to significantly vary between locations with different tree cover and neighborhood characteristics for the full study time period as well as for the top 10% of heat index days. This work demonstrates the need for high-resolution climate data and the use of additional measures beyond temperature to understand urban neighborhood exposure to extreme heat, and expresses the importance of considering vulnerability differences among residents when analyzing neighborhood-scale impacts.

Dynamic assessments of population exposure to urban greenspace using multi-source big data.

PubMed

Song, Yimeng; Huang, Bo; Cai, Jixuan; Chen, Bin

2018-09-01

A growing body of evidence has proven that urban greenspace is beneficial to improve people's physical and mental health. However, knowledge of population exposure to urban greenspace across different spatiotemporal scales remains unclear. Moreover, the majority of existing environmental assessments are unable to quantify how residents enjoy their ambient greenspace during their daily life. To deal with this challenge, we proposed a dynamic method to assess urban greenspace exposure with the integration of mobile-phone locating-request (MPL) data and high-spatial-resolution remote sensing images. This method was further applied to 30 major cities in China by assessing cities' dynamic greenspace exposure levels based on residents' surrounding areas with different buffer scales (0.5km, 1km, and 1.5km). Results showed that regarding residents' 0.5-km surrounding environment, Wenzhou and Hangzhou were found to be with the greenest exposure experience, whereas Zhengzhou and Tangshan were the least ones. The obvious diurnal and daily variations of population exposure to their surrounding greenspace were also identified to be highly correlated with the distribution pattern of urban greenspace and the dynamics of human mobility. Compared with two common measurements of urban greenspace (green coverage rate and green area per capita), the developed method integrated the dynamics of population distribution and geographic locations of urban greenspace into the exposure assessment, thereby presenting a more reasonable way to assess population exposure to urban greenspace. Additionally, this dynamic framework could hold potential utilities in supporting urban planning studies and environmental health studies and advancing our understanding of the magnitude of population exposure to greenspace at different spatiotemporal scales. Copyright © 2018 Elsevier B.V. All rights reserved.

Isotopic Recorders of Pollution in Heterogeneous Urban Areas

NASA Astrophysics Data System (ADS)

Pataki, D. E.; Cobley, L.; Smith, R. M.; Ehleringer, J. R.; Chritz, K.

2017-12-01

A significant difficulty in quantifying urban pollution lies in the extreme spatial and temporal heterogeneity of cities. Dense sources of both point and non-point source pollution as well as the dynamic role of human activities, which vary over very short time scales and small spatial scales, complicate efforts to establish long-term urban monitoring networks that are relevant at neighborhood, municipal, and regional scales. Fortunately, the natural abundance of isotopes of carbon, nitrogen, and other elements provides a wealth of information about the sources and fate of urban atmospheric pollution. In particular, soils and plant material integrate pollution sources and cycling over space and time, and have the potential to provide long-term records of pollution dynamics that extend back before atmospheric monitoring data are available. Similarly, sampling organic material at high spatial resolution can provide "isoscapes" that shed light on the spatial heterogeneity of pollutants in different urban parcels and neighborhoods, along roads of varying traffic density, and across neighborhoods of varying affluence and sociodemographic composition. We have compiled numerous datasets of the isotopic composition of urban organic matter that illustrate the potential for isotopic monitoring of urban areas as a means of understanding hot spots and hot moments in urban atmospheric biogeochemistry. Findings to date already reveal the critical role of affluence, economic activity, demographic change, and land management practices in influencing urban pollution sources and sinks, and suggest an important role of stable isotope and radioisotope measurements in urban atmospheric and biogeochemical monitoring.

Controls on Biogeochemical Cycling of Nitrogen in Urban Ecosystems

NASA Astrophysics Data System (ADS)

Templer, P. H.; Hutyra, L.; Decina, S.; Rao, P.; Gately, C.

2017-12-01

Rates of atmospheric nitrogen deposition are declining across much of the United States and Europe, yet they remain substantially elevated by almost an order of magnitude over pre-industrial levels and occur as hot spots in urban areas. We measured atmospheric inputs of inorganic and organic nitrogen in multiple urban sites around the Boston Metropolitan area, finding that urban rates are substantially elevated compared to nearby rural areas, and that the range of these atmospheric inputs are as large as observed urban to rural gradients. Within the City of Boston, the variation in deposition fluxes can be explained by traffic intensity, vehicle emissions, and spring fertilizer additions. Throughfall inputs of nitrogen are approximately three times greater than bulk deposition inputs in the city, demonstrating that the urban canopy amplifies rates of nitrogen reaching the ground surface. Similar to many other metropolitan areas of the United States, the City of Boston has 25% canopy cover; however, 25% of this tree canopy is located above impervious pavement. Throughfall inputs that do not have soil below the canopy to retain excess nitrogen may lead to greater inputs of nitrogen into nearby waterways through runoff. Most measurement stations for atmospheric nitrogen deposition are intentionally located away from urban areas and point sources of pollution to capture regional trends. Our data show that a major consequence of this network design is that hotspots of nitrogen deposition and runoff into urban and coastal waterways is likely underestimated to a significant degree. A more complete determination of atmospheric nitrogen deposition and its fate in urban ecosystems is critical for closing regional nitrogen budgets and for improving our understanding of biogeochemical nitrogen cycling across multiple spatial scales.

Radiative transfer in a polluted urban planetary boundary layer

NASA Technical Reports Server (NTRS)

Viskanta, R.; Johnson, R. O.; Bergstrom, R. W.

1977-01-01

Radiative transfer in a polluted urban atmosphere is studied using a dynamic model. The diurnal nature of radiative transfer for summer conditions is simulated for an urban area 40 km in extent and the effects of various parameters arising in the problem are investigated. The results of numerical computations show that air pollution has the potential of playing a major role in the radiative regime of the urban area. Absorption of solar energy by aerosols in realistic models of urban atmosphere are of the same order of magnitude as that due to water vapor. The predicted effect of the air pollution aerosol in the city is to warm the earth-atmosphere system, and the net effect of gaseous pollutant is to warm the surface and cool the planetary boundary layer, particularly near the top.

Effect of urbanization on the thermal structure in the atmosphere

Treesearch

R. Viskanta; R. O. Johnson; R. W., Jr. Bergstrom

1977-01-01

An unsteady two-dimensional transport model was used to study the short-term effects of urbanization and air pollution on the thermal structure in the urban atmosphere. A number of simulations for summer conditions representing the city of St. Louis were performed. The diurnal variation of the surface temperature and thermal structure are presented and the influences...

History of Inuit Community Exposure to Lead, Cadmium, and Mercury in Sewage Lake Sediments

PubMed Central

Hermanson, Mark H.; Brozowski, James R.

2005-01-01

Exposure to lead, cadmium, and mercury is known to be high in many arctic Inuit communities. These metals are emitted from industrial and urban sources, are distributed by long-range atmospheric transport to remote regions, and are found in Inuit country foods. Current community exposure to these metals can be measured in food, but feces and urine are also excellent indicators of total exposure from ingestion and inhalation because a high percentage of each metal is excreted. Bulk domestic sewage or its residue in a waste treatment system is a good substitute measure. Domestic waste treatment systems that accumulate metals in sediment provide an accurate historical record of changes in ingestion or inhalation. We collected sediment cores from an arctic lake used for facultative domestic sewage treatment to identify the history of community exposure to Pb, Cd, and Hg. Cores were dated and fluxes were measured for each metal. A nearby lake was sampled to measure combined background and atmospheric inputs, which were subtracted from sewage lake data. Pb, Cd, and Hg inputs from sewage grew rapidly after the onset of waste disposal in the late 1960s and exceeded the rate of population growth in the contributing community from 1970 to 1990. The daily per-person Pb input in 1990 (720,000 ng/person per day) exceeded the tolerable daily intake level. The Cd input (48,000 ng/person per day) and Hg input (19,000 ng/person per day) were below the respective TDI levels at the time. PMID:16203239

Continental-scale distributions of dust-associated bacteria and fungi

PubMed Central

Barberán, Albert; Ladau, Joshua; Pollard, Katherine S.; Menninger, Holly L.; Dunn, Robert R.; Fierer, Noah

2015-01-01

It has been known for centuries that microorganisms are ubiquitous in the atmosphere, where they are capable of long-distance dispersal. Likewise, it is well-established that these airborne bacteria and fungi can have myriad effects on human health, as well as the health of plants and livestock. However, we have a limited understanding of how these airborne communities vary across different geographic regions or the factors that structure the geographic patterns of near-surface microbes across large spatial scales. We collected dust samples from the external surfaces of ∼1,200 households located across the United States to understand the continental-scale distributions of bacteria and fungi in the near-surface atmosphere. The microbial communities were highly variable in composition across the United States, but the geographic patterns could be explained by climatic and soil variables, with coastal regions of the United States sharing similar airborne microbial communities. Although people living in more urbanized areas were not found to be exposed to distinct outdoor air microbial communities compared with those living in more rural areas, our results do suggest that urbanization leads to homogenization of the airborne microbiota, with more urban communities exhibiting less continental-scale geographic variability than more rural areas. These results provide our first insight into the continental-scale distributions of airborne microbes, which is information that could be used to identify likely associations between microbial exposures in outdoor air and incidences of disease in crops, livestock, and humans. PMID:25902536

Assessment of atmospheric trace metal deposition in urban environments using direct and indirect measurement methodology and contributions from wet and dry depositions

NASA Astrophysics Data System (ADS)

Omrani, Mehrazin; Ruban, Véronique; Ruban, Gwenaël; Lamprea, Katerine

2017-11-01

Bulk Atmospheric Deposition (BAD), Wet Atmospheric Deposition (WAD) and Dry Atmospheric Deposition (DAD) were all measured within an urban residential area in Nantes (France) over a 9-month period (27 February - 10 December 2014). The objectives of this study were to compare 2 methods for measuring dry and wet atmospheric depositions in the urban environment (DAD and WAD: direct method; BAD and WAD: indirect one), and to characterize as well the variations and relative contributions of these depositions. Trace metals (As, Cd, Cr, Cu, Ni, Pt and V) were used to carry out these comparison and quantification. BAD was collected with two open polyethylene containers (72 × 54 × 21 cm), while WAD was collected by means of an automated rainwater collector and DAD was determined from both air measurements (recorded by an air sampler) and 7Be deposition velocities. The comparison based on a detailed evaluation of uncertainties showed a significant difference between the direct and indirect methods. Dry and wet depositions varied widely from one month to the next. Zn and Cu were the most abundant elements in both dry and wet depositions. The mean contribution of DAD to the bulk atmospheric deposition during this 9-month study was significant for Zn, Cu and V (about 25%) as well as for Pb (approx. 60%). For this relatively unpolluted urban residential catchment, the contribution of atmospheric deposition to global load at the catchment outlet was low, between 10% and 20% for Zn, Cu, V and Pb, 25% for Cr and about 30% for Ni. For other urban sites exhibiting high atmospheric pollution however, the atmospheric contribution to the global pollution load could be much greater. An accurate and representative estimation of DAD thus proves critical.

Elucidating the urban levels, sources and health risks of polycyclic aromatic hydrocarbons (PAHs) in Pakistan: Implications for changing energy demand.

PubMed

Hamid, Naima; Syed, Jabir Hussain; Junaid, Muhammad; Mahmood, Adeel; Li, Jun; Zhang, Gan; Malik, Riffat Naseem

2018-04-01

Due to the severe fuel crisis in terms of natural gas, a paradigm shift in fuel combustion (diesel, gasoline, and biomass) may increase the atmospheric emissions and associated health risks in Pakistan. Present study was aimed to investigate the concentration of fugitive PAHs in the environment (outdoor and indoor settings), associated probabilistic health risk assessment in the exposed population, and possible linkage between fuel consumption patterns and PAHs emissions in twin cities (Rawalpindi and Islamabad) of Pakistan. Results showed that the mean PAHs concentrations (air: 2390pgm -3 ; dust: 167ngg -1 ) in the indoor environment were higher than that of the outdoor environment (air: 2132pgm -3 ; dust: 90.0ngg -1 ). Further, the source apportionment PCA-MLR receptor model identified diesel and gasoline combustion as the primary PAHs sources in the urban and sub-urban settings. Estimated life cancer risk (LCR) potential via inhalation to indoor PAHs was higher with a probability of 2.0 cases per 10,000 inhabitants as compared to outdoor exposure. Incremental lifetime cancer risk (ILCR) model from exposure to dust bound PAHs showed risk in the order of ingestion>dermal>inhalation for various exposure pathways. Likewise, estimated daily intake (EDI) model reflects that PAHs in surface dust enter into the human body mainly through the respiratory system because EDI for breathing was reported higher than that of oral intake. Therefore, adoption of sustainable fuels is recommended to meet the energy requirements and to reduce PAHs emissions and related health risks in the twin cities of Pakistan. Copyright © 2017 Elsevier B.V. All rights reserved.

Simulating the dispersion of NOx and CO2 in the city of Zurich at building resolving scale

NASA Astrophysics Data System (ADS)

Brunner, Dominik; Berchet, Antoine; Emmenegger, Lukas; Henne, Stephan; Müller, Michael

2017-04-01

Cities are emission hotspots for both greenhouse gases and air pollutants. They contribute about 70% of global greenhouse gas emissions and are home to a growing number of people potentially suffering from poor air quality in the urban environment. High-resolution atmospheric transport modelling of greenhouse gases and air pollutants at the city scale has, therefore, several important applications such as air pollutant exposure assessment, air quality forecasting, or urban planning and management. When combined with observations, it also has the potential to quantify emissions and monitor their long-term trends, which is the main motivation for the deployment of urban greenhouse gas monitoring networks. We have developed a comprehensive atmospheric modeling model system for the city of Zurich, Switzerland ( 600,000 inhabitants including suburbs), which is composed of the mesoscale model GRAMM simulating the flow in a larger domain around Zurich at 100 m resolution, and the nested high-resolution model GRAL simulating the flow and air pollutant dispersion in the city at building resolving (5-10 m) scale. Based on an extremely detailed emission inventory provided by the municipality of Zurich, we have simulated two years of hourly NOx and CO2 concentration fields across the entire city. Here, we present a detailed evaluation of the simulations against a comprehensive network of continuous monitoring sites and passive samplers for NOx and analyze the sensitivity of the results to the temporal variability of the emissions. Furthermore, we present first simulations of CO2 and investigate the challenges associated with CO2 sources not covered by the inventory such as human respiration and exchange fluxes with urban vegetation.

Pathogen exposure varies widely among sympatric populations of wild and domestic felids across the United States

USGS Publications Warehouse

Carver, Scott; Bevins, Sarah N.; Lappin, Michael R.; Boydston, Erin E.; Lyren, Lisa M.; Alldredge, Mathew W.; Logan, Kenneth A.; Sweanor, Linda L.; Riley, Seth P.D.; Serieys, Laurel E.K.; Fisher, Robert N.; Vickers, T. Winston; Boyce, Walter M.; McBride, Roy; Cunnigham, Mark C.; Jennings, Megan; Lewis, Jesse S.; Lunn, Tamika; Crooks, Kevin R.; VandeWoude, Sue

2016-01-01

Understanding how landscape, host, and pathogen traits contribute to disease exposure requires systematic evaluations of pathogens within and among host species and geographic regions. The relative importance of these attributes is critical for management of wildlife and mitigating domestic animal and human disease, particularly given rapid ecological changes, such as urbanization. We screened >1,000 samples from sympatric populations of puma (Puma concolor), bobcat (Lynx rufus) and domestic cat (Felis catus) across urban gradients in six sites, representing three regions, in North America for exposure to a representative suite of bacterial, protozoal and viral pathogens (Bartonella sp., Toxoplasma gondii, feline herpesvirus-1, feline panleukopenea virus, feline calicivirus, feline immunodeficiency virus). We evaluated prevalence within each species, and examined host trait and land cover determinants of exposure-providing an unprecedented analysis of factors relating to potential for infections in domesticated and wild felids. Prevalence differed among host species (highest for puma and lowest for domestic cat) and was greater for indirectly transmitted pathogens. Sex was inconsistently predictive of exposure to directly transmitted pathogens only, and age infrequently predictive of both direct and indirectly transmitted pathogens. Determinants of pathogen exposure were widely divergent between the wild felid species. For puma, suburban landuse predicted increased exposure to Bartonella sp. in southern California, and FHV-1 exposure increased near urban edges in Florida. This may suggest inter-specific transmission with domestic cats via flea vectors (California) and direct contact (Florida) around urban boundaries. Bobcats captured near urban areas had increased exposure to T. gondii in Florida, suggesting an urban source of prey. Bobcats captured near urban areas in Colorado and Florida had higher FIV exposure, possibly suggesting increased intra-specific interactions through pile-up of home ranges. Beyond these regional and pathogen specific relationships, proximity to the wildland urban interface did not generally increase the probability of disease exposure in wild or domestic felids, emphasizing the importance of local ecological determinants. Indeed, pathogen exposure was often negatively associated with the wildland urban interface for all felids. Our analyses suggest cross-species pathogen transmission events around this interface may be infrequent, but followed by self-sustaining propagation within the new host species.

Cumulative health risk assessment of halogenated and parent polycyclic aromatic hydrocarbons associated with particulate matters in urban air.

PubMed

Sun, Jian-Lin; Jing, Xin; Chang, Wen-Jing; Chen, Zheng-Xia; Zeng, Hui

2015-03-01

Halogenated polycyclic aromatic hydrocarbons (HPAHs) have been reported to occur widely in urban air. Nevertheless, knowledge about the human health risk associated with inhalation exposure to HPAHs is scarce so far. In the present study, nine HPAHs and 16 PAHs were determined in atmospheric particulate matter (PM) collected from Shenzhen, China to address this issue. Concentrations of Σ9HPAHs varied from 0.1 to 1.5 ng/m(3) and from 0.09 to 0.4 ng/m(3) in PM10 and PM2.5 samples, respectively. As for individuals, 9-bromoanthracene, 7-bromobenz(a)anthracene, and 9,10-dibromoanthracene were the dominant congeners. Levels of Σ16PAHs in PM10 and PM2.5 samples ranged from 3.2 to 81 ng/m(3) and from 2.8 to 85 ng/m(3), respectively. Among individual PAHs, chrysene, benzo[b]fluoranthene, and indeno[1,2,3-c,d]pyrene were the main congeners. According to the season, concentrations of HPAHs and PAHs in atmospheric PM10/PM2.5 samples show a similar decreasing trend with an order: winter>autumn>spring>summer. The daily intake (DI) of PM10/PM2.5-bound HPAHs and PAHs were estimated. Our results indicated that children have the highest DI levels via inhalation exposure. The incremental lifetime cancer risk (ILCR) induced by PM10/PM2.5-bound HPAHs and PAHs were calculated. The ILCR values showed a similar decreasing trend with an order: adults>children>seniors>adolescent. Overall, the ILCR values induced by HPAHs and PAHs were far below the priority risk level (10(-4)), indicating no obvious cancer risk. To our knowledge, this is the first study to investigate the human health risk associated with inhalation exposure to PM10/PM2.5-bound HPAHs. Copyright © 2014 Elsevier Inc. All rights reserved.

Atmospheric mercury accumulation and washoff processes on impervious urban surfaces

USGS Publications Warehouse

Eckley, C.S.; Branfireun, B.; Diamond, M.; Van Metre, P.C.; Heitmuller, F.

2008-01-01

The deposition and transport of mercury (Hg) has been studied extensively in rural environments but is less understood in urbanized catchments, where elevated atmospheric Hg concentrations and impervious surfaces may efficiently deliver Hg to waterways in stormwater runoff. We determined the rate at which atmospheric Hg accumulates on windows, identified the importance of washoff in removing accumulated Hg, and measured atmospheric Hg concentrations to help understand the relationship between deposition and surface accumulation. The main study location was Toronto, Ontario. Similar samples were also collected from Austin, Texas for comparison of Hg accumulation between cities. Windows provided a good sampling surface because they are ubiquitous in urban environments and are easy to clean/blank allowing the assessment of contemporary Hg accumulation. Hg Accumulation rates were spatially variable ranging from 0.82 to 2.7 ng m-2 d-1 in Toronto and showed similar variability in Austin. The highest accumulation rate in Toronto was at the city center and was 5?? higher than the rural comparison site (0.58 ng m-2 d-1). The atmospheric total gaseous mercury (TGM) concentrations were less than 2?? higher between the rural and urban locations (1.7 ?? 0.3 and 2.7 ?? 1.1 ng m-3, respectively). The atmospheric particulate bound fraction (HgP), however, was more than 3?? higher between the rural and urban sites, which may have contributed to the higher urban Hg accumulation rates. Windows exposed to precipitation had 73 ?? 9% lower accumulation rates than windows sheltered from precipitation. Runoff collected from simulated rain events confirmed that most Hg accumulated on windows was easily removed and that most of the Hg in washoff was HgP. Our results indicate that the Hg flux from urban catchments will respond rapidly to changes in atmospheric concentrations due to the mobilization of the majority of the surface accumulated Hg during precipitation events. ?? 2008 Elsevier Ltd.

Sulphur isotopic ratios in mosses indicating atmospheric sulphur sources in southern Chinese mountainous areas

NASA Astrophysics Data System (ADS)

Xiao, Hua-Yun; Tang, Cong-Guo; Liu, Xue-Yan; Xiao, Hong-Wei; Liu, Cong-Qiang

2008-10-01

Many mountainous regions in South China have been confronted with the consequences of acidic deposition, but studies on atmospheric S sources are still very limited. In this study, isotopic ratios in mosses were used to discriminate atmospheric S sources. A continuous increase in S isotopic ratios was observed from the south to the north in mountainous mosses and in accord with the previously reported changing trends in urban mosses, indicating a contribution of local anthropogenic S from urban cities. Based on comparisons of S isotopic ratios in mountainous mosses with those in nearby urban mosses, we found that mountainous mosses had significantly higher 34S contents than urban mosses, especially in West China, reflecting an introduction of 34S-enriched sulphur. In conjunction with cloud water data in the literature, we concluded that 34S-enriched sulphur in northerly air masses contributed much to atmospheric S in southern Chinese mountainous areas.

Estimating the deposition of urban atmospheric NO2 to the urban forest in Portland-Vancouver USA

NASA Astrophysics Data System (ADS)

Rao, M.; Gonzalez Abraham, R.; George, L. A.

2016-12-01

Cities are hotspots of atmospheric emissions of reactive nitrogen oxides, including nitrogen dioxide (NO2), a US EPA criteria pollutant that affects both human and environmental health. A fraction of this anthropogenic, atmospheric NO2 is deposited onto the urban forest, potentially mitigating the impact of NO2 on respiratory health within cities. However, the role of the urban forest in removal of atmospheric NO2 through deposition has not been well studied. Here, using an observationally-based statistical model, we first estimate the reduction of NO2 associated with the urban forest in Portland-Vancouver, USA, and the health benefits accruing from this reduction. In order to assess if this statistically observed reduction in NO2 associated with the urban forest is consistent with deposition, we then compare the amount of NO2 removed through deposition to the urban forest as estimated using a 4km CMAQ simulation. We further undertake a sensitivity analysis in CMAQ to estimate the range of NO2removed as a function of bulk stomatal resistance. We find that NO2 deposition estimated by CMAQ accounts for roughly one-third of the reduction in NO2 shown by the observationally-based statistical model (Figure). Our sensitivity analysis shows that a 3-10 fold increase in the bulk stomatal resistance parameter in CMAQ would align CMAQ-estimated deposition with the statistical model. The reduction of NO2 by the urban forest in the Portland-Vancouver area may yield a health benefit of at least $1.5 million USD annually, providing strong motivation to better understand the mechanism through which the urban forest may be removing air pollutants such as NO2and thus helping create healthier urban atmospheres. Figure: Comparing the amount of NO2 deposition as estimated by CMAQ and the observationally-based statistical model (LURF). Each point corresponds to a single 4 x 4km CMAQ grid cell.

Variability, drivers, and effects of atmospheric nitrogen inputs across an urban area: Emerging patterns among human activities, the atmosphere, and soils.

PubMed

Decina, Stephen M; Templer, Pamela H; Hutyra, Lucy R; Gately, Conor K; Rao, Preeti

2017-12-31

Atmospheric deposition of nitrogen (N) is a major input of N to the biosphere and is elevated beyond preindustrial levels throughout many ecosystems. Deposition monitoring networks in the United States generally avoid urban areas in order to capture regional patterns of N deposition, and studies measuring N deposition in cities usually include only one or two urban sites in an urban-rural comparison or as an anchor along an urban-to-rural gradient. Describing patterns and drivers of atmospheric N inputs is crucial for understanding the effects of N deposition; however, little is known about the variability and drivers of atmospheric N inputs or their effects on soil biogeochemistry within urban ecosystems. We measured rates of canopy throughfall N as a measure of atmospheric N inputs, as well as soil net N mineralization and nitrification, soil solution N, and soil respiration at 15 sites across the greater Boston, Massachusetts area. Rates of throughfall N are 8.70±0.68kgNha -1 yr -1 , vary 3.5-fold across sites, and are positively correlated with rates of local vehicle N emissions. Ammonium (NH 4 + ) composes 69.9±2.2% of inorganic throughfall N inputs and is highest in late spring, suggesting a contribution from local fertilizer inputs. Soil solution NO 3 - is positively correlated with throughfall NO 3 - inputs. In contrast, soil solution NH 4 + , net N mineralization, nitrification, and soil respiration are not correlated with rates of throughfall N inputs. Rather, these processes are correlated with soil properties such as soil organic matter. Our results demonstrate high variability in rates of urban throughfall N inputs, correlation of throughfall N inputs with local vehicle N emissions, and a decoupling of urban soil biogeochemistry and throughfall N inputs. Copyright © 2017 Elsevier B.V. All rights reserved.

Gaseous VOCs rapidly modify particulate matter and its biological effects – Part 1: Simple VOCs and model PM

PubMed Central

Ebersviller, S.; Lichtveld, K.; Sexton, K. G.; Zavala, J.; Lin, Y-H.; Jaspers, I.; Jeffries, H. E.

2013-01-01

This is the first of a three-part study designed to demonstrate dynamic entanglements among gaseous organic compounds (VOC), particulate matter (PM), and their subsequent potential biological effects. We study these entanglements in increasingly complex VOC and PM mixtures in urban-like conditions in a large outdoor chamber. To the traditional chemical and physical characterizations of gas and PM, we added new measurements of gas-only- and PM-only-biological effects, using cultured human lung cells as model indicators. These biological effects are assessed here as increases in cellular damage or expressed irritation (i.e., cellular toxic effects) from cells exposed to chamber air relative to cells exposed to clean air. The exposure systems permit gas-only- or PM-only-exposures from the same air stream containing both gases and PM in equilibria, i.e., there are no extractive operations prior to cell exposure. Our simple experiments in this part of the study were designed to eliminate many competing atmospheric processes to reduce ambiguity in our results. Simple volatile and semi-volatile organic gases that have inherent cellular toxic properties were tested individually for biological effect in the dark (at constant humidity). Airborne mixtures were then created with each compound and PM that has no inherent cellular toxic properties for another cellular exposure. Acrolein and p-tolualdehyde were used as model VOCs and mineral oil aerosol (MOA) was selected as a surrogate for organic-containing PM. MOA is appropriately complex in composition to represent ambient PM, and it exhibits no inherent cellular toxic effects and thus did not contribute any biological detrimental effects on its own. Chemical measurements, combined with the responses of our biological exposures, clearly demonstrate that gas-phase pollutants can modify the composition of PM (and its resulting detrimental effects on lung cells) – even if the gas-phase pollutants are not considered likely to partition to the condensed phase: the VOC-modified-PM showed significantly more damage and inflammation to lung cells than did the original PM. Because gases and PM are transported and deposited differently within the atmosphere and the lungs, these results have significant consequences. For example, current US policies for research and regulation of PM do not recognize this “effect modification” phenomena (NAS, 2004). These results present an unambiguous demonstration that – even in these simple mixtures – physical and thermal interactions alone can cause a modification of the distribution of species among the phases of airborne pollution mixtures and can result in a non-toxic phase becoming toxic due to atmospheric thermal processes only. Subsequent work extends the simple results reported here to systems with photochemical transformations of complex urban mixtures and to systems with diesel exhaust produced by different fuels. PMID:23457430

Low-cost, high-density sensor network for urban emission monitoring: BEACO2N

NASA Astrophysics Data System (ADS)

Kim, J.; Shusterman, A.; Lieschke, K.; Newman, C.; Cohen, R. C.

2017-12-01

In urban environments, air quality is spatially and temporally heterogeneous as diverse emission sources create a high degree of variability even at the neighborhood scale. Conventional air quality monitoring relies on continuous measurements with limited spatial resolution or passive sampling with high-density and low temporal resolution. Either approach averages the air quality information over space or time and hinders our attempts to understand emissions, chemistry, and human exposure in the near-field of emission sources. To better capture the true spatio-temporal heterogeneity of urban conditions, we have deployed a low-cost, high-density air quality monitoring network in San Francisco Bay Area distributed at 2km horizontal spacing. The BErkeley Atmospheric CO2 Observation Network (BEACO2N) consists of approximately 50 sensor nodes, measuring CO2, CO, NO, NO2, O­3, and aerosol. Here we describe field-based calibration approaches that are consistent with the low-cost strategy of the monitoring network. Observations that allow inference of emission factors and identification of specific local emission sources will also be presented.

Estimation of exposure to atmospheric pollutants during pregnancy integrating space-time activity and indoor air levels: does it make a difference?

PubMed Central

Marion, OUIDIR; Lise, GIORGIS-ALLEMAND; Sarah, LYON-CAEN; Xavier, MORELLI; Claire, CRACOWSKI; Sabrina, PONTET; Isabelle, PIN; Johanna, LEPEULE; Valérie, SIROUX; Rémy, SLAMA

2016-01-01

Studies of air pollution effects during pregnancy generally only consider exposure in the outdoor air at the home address. We aimed to compare exposure models differing in their ability to account for the spatial resolution of pollutants, space-time activity and indoor air pollution levels. We recruited 40 pregnant women in the Grenoble urban area, France, who carried a Global Positioning System (GPS) during up to 3 weeks; in a subgroup, indoor measurements of fine particles (PM2.5) were conducted at home (n=9) and personal exposure to nitrogen dioxide (NO2) was assessed using passive air samplers (n=10). Outdoor concentrations of NO2, and PM2.5 were estimated from a dispersion model with a fine spatial resolution. Women spent on average 16 h per day at home. Considering only outdoor levels, for estimates at the home address, the correlation between the estimate using the nearest background air monitoring station and the estimate from the dispersion model was high (r=0.93) for PM2.5 and moderate (r=0.67) for NO2. The model incorporating clean GPS data was less correlated with the estimate relying on raw GPS data (r=0.77) than the model ignoring space-time activity (r=0.93). PM2.5 outdoor levels were not to moderately correlated with estimates from the model incorporating indoor measurements and space-time activity (r=−0.10 to 0.47), while NO2 personal levels were not correlated with outdoor levels (r=−0.42 to 0.03). In this urban area, accounting for space-time activity little influenced exposure estimates; in a subgroup of subjects (n=9), incorporating indoor pollution levels seemed to strongly modify them. PMID:26300245

Increase in the CO2 exchange rate of leaves of Ilex rotunda with elevated atmospheric CO2 concentration in an urban canyon

NASA Astrophysics Data System (ADS)

Takagi, M.; Gyokusen, Koichiro; Saito, Akira

It was found that the atmospheric carbon dioxide (CO2) concentration in an urban canyon in Fukuoka city, Japan during August 1997 was about 30 µmol mol-1 higher than that in the suburbs. When fully exposed to sunlight, in situ the rate of photosynthesis in single leaves of Ilex rotunda planted in the urban canyon was higher when the atmospheric CO2 concentration was elevated. A biochemically based model was able to predict the in situ rate of photosynthesis well. The model also predicted an increase in the daily CO2 exchange rate for leaves in the urban canyon with an increase in atmospheric CO2 concentration. However, in situ such an increase in the daily CO2 exchange rate may be offset by diminished sunlight, a higher air temperature and a lower relative humidity. Thus, the daily CO2 exchange rate predicted using the model based soleley on the environmental conditions prevailing in the urban canyon was lower than that predicted based only on environmental factors found in the suburbs.

Rural Villagers and Urban Residents Exposure to Poultry in China

PubMed Central

Shi, Ying; Liao, Qiaohong; Zhou, Hang; Zhou, Lei; Li, Leilei; Wu, Jiabing; Zhang, Shunxiang; Yu, Zhangda; Wu, Xiaomin; Ma, Hanwu; Lu, Jianhua; Cowling, Benjamin J.; Yu, Hongjie

2014-01-01

Patterns of poultry exposure in rural and urban areas in China have not been systematically evaluated and compared. The objective of our study is to investigate patterns in human exposure to poultry in rural and urban China. We conducted a two-stage household-based clustered survey on population exposure to live/sick/dead poultry in Xiuning and Shenzhen. Half of the rural households (51%) in Xiuning raised poultry, mostly (78%) free-range. Around half of those households (40%) allowed poultry to stay in their living areas. One quarter of villagers reported having contact with sick or dead poultry. In Shenzhen, 37% urban residents visited live poultry markets. Among these, 40% purchased live poultry and 16% touched the poultry or cages during purchase. Our findings indicated that human exposure to poultry was different in rural and urban areas in China. This discrepancy could contribute to the observed differences in epidemiologic characteristics between urban and rural cases of influenza A(H7N9) and A(H5N1) virus infection. PMID:24769673

"Coming to town": the impact of urbanicity, cigarette advertising, and network norms on the smoking attitudes of black women in Cape Town, South Africa.

PubMed

Williams, Chyvette T; Grier, Sonya A; Marks, Amy Seidel

2008-07-01

This study was conducted to examine the effect of urban living on smoking attitudes among black African women in South Africa. We examine how urbanicity affects attitudes toward smoking and how it moderates the relationship between both advertising exposure and network norms on black women's smoking attitudes. Respondents were 975 black women currently living in Cape Town townships, some of which were raised in rural villages or small towns. Respondents completed a cross-sectional survey, which included data on smoking attitudes, norms, and exposure to cigarette advertising. Multiple linear regression analysis was performed with smoking attitudes as the response variable, and urbanicity, cigarette advertising exposure, and network smoking norms as primary explanatory variables. Interactions were tested to determine whether urbanicity modified the effect of advertising exposure and network norms on smoking attitudes. Independent effects of urbanicity, exposure to cigarette advertising, and greater smoking prevalence within women's networks were associated with more favorable smoking attitudes. In addition, urbanicity moderated the relationship between network smoking norms and smoking attitudes, but not cigarette advertising exposure and smoking attitudes. Urbanicity, cigarette advertising, and networks play important roles in women's attitudes toward smoking, and potentially, smoking behavior. Overall, our results suggest that strong and creative anti-smoking efforts are needed to combat the potential for a smoking epidemic among an increasingly urbanized population of black women in South Africa and similar emerging markets. Additional research is warranted.

“Coming to Town”: The Impact of Urbanicity, Cigarette Advertising, and Network Norms on the Smoking Attitudes of Black Women in Cape Town, South Africa

PubMed Central

Williams, Chyvette T.; Marks, Amy Seidel

2008-01-01

This study was conducted to examine the effect of urban living on smoking attitudes among black African women in South Africa. We examine how urbanicity affects attitudes toward smoking and how it moderates the relationship between both advertising exposure and network norms on black women’s smoking attitudes. Respondents were 975 black women currently living in Cape Town townships, some of which were raised in rural villages or small towns. Respondents completed a cross-sectional survey, which included data on smoking attitudes, norms, and exposure to cigarette advertising. Multiple linear regression analysis was performed with smoking attitudes as the response variable, and urbanicity, cigarette advertising exposure, and network smoking norms as primary explanatory variables. Interactions were tested to determine whether urbanicity modified the effect of advertising exposure and network norms on smoking attitudes. Independent effects of urbanicity, exposure to cigarette advertising, and greater smoking prevalence within women’s networks were associated with more favorable smoking attitudes. In addition, urbanicity moderated the relationship between network smoking norms and smoking attitudes, but not cigarette advertising exposure and smoking attitudes. Urbanicity, cigarette advertising, and networks play important roles in women’s attitudes toward smoking, and potentially, smoking behavior. Overall, our results suggest that strong and creative anti-smoking efforts are needed to combat the potential for a smoking epidemic among an increasingly urbanized population of black women in South Africa and similar emerging markets. Additional research is warranted. PMID:18563573

Urbanization and the Carbon Cycle: Synthesis of Ongoing Research

NASA Astrophysics Data System (ADS)

Gurney, K. R.; Duren, R. M.; Hutyra, L.; Ehleringer, J. R.; Patarasuk, R.; Song, Y.; Huang, J.; Davis, K.; Kort, E. A.; Shepson, P. B.; Turnbull, J. C.; Lauvaux, T.; Rao, P.; Eldering, A.; Miller, C. E.; Wofsy, S.; McKain, K.; Mendoza, D. L.; Lin, J. C.; Sweeney, C.; Miles, N. L.; Richardson, S.; Cambaliza, M. O. L.

2015-12-01

Given the explosive growth in urbanization and its dominant role in current and future global greenhouse gas emissions, urban areas have received increasing research attention from the carbon cycle science community. The emerging focus is driven by the increasingly dense atmospheric observing capabilities - ground and space-based - in addition to the rising profile of cities within international climate change policymaking. Dominated by anthropogenic emissions, urban carbon cycle research requires a cross-disciplinary perspective with contributions from disciplines such as engineering, economics, social theory, and atmospheric science. We review the recent results from a sample of the active urban carbon research efforts including the INFLUX experiment (Indianapolis), the Megacity carbon project (Los Angeles), Salt Lake City, and Boston. Each of these efforts represent unique approaches in pursuit of different scientific and policy questions and assist in setting priorities for future research. From top-down atmospheric measurement systems to bottom-up estimation, these research efforts offer a view of the challenges and opportunities in urban carbon cycle research.

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T.E. KLEINDIENST, E.W. CORSE, F.T. BLANCHARD, W.A. LONNEMAN

EPA Science Inventory

Carbonyl compounds are important constituents in urban and global atmospheres. n urban atmospheres these compounds frequently serve to initiate photochemical smog and certainly sustain the chain reactions leading to ozone formation. easurement of carbonyl compounds under atmosphe...

Concluding remarks: Faraday Discussion on chemistry in the urban atmosphere.

PubMed

Jimenez, Jose L

2016-07-18

This article summarises the Concluding remarks from the Faraday Discussion on Chemistry in the Urban Atmosphere. The following themes are addressed: (a) new results that inform our understanding of the evolving sources and composition of the urban atmosphere ("News"); (b) results that identify gaps in our understanding that necessitate further work ("Gaps"); (c) the emerging instrumentation revolution and some of the challenges that it brings; (d) the structural issues of insufficient support for the analysis of field campaigns; and (e) some important areas that were missing from this Faraday Discussion and that should receive an increasing focus in the future.

Synthetic fibers in atmospheric fallout: A source of microplastics in the environment?

PubMed

Dris, Rachid; Gasperi, Johnny; Saad, Mohamed; Mirande, Cécile; Tassin, Bruno

2016-03-15

Sources, pathways and reservoirs of microplastics, plastic particles smaller than 5mm, remain poorly documented in an urban context. While some studies pointed out wastewater treatment plants as a potential pathway of microplastics, none have focused on the atmospheric compartment. In this work, the atmospheric fallout of microplastics was investigated in two different urban and sub-urban sites. Microplastics were collected continuously with a stainless steel funnel. Samples were then filtered and observed with a stereomicroscope. Fibers accounted for almost all the microplastics collected. An atmospheric fallout between 2 and 355 particles/m(2)/day was highlighted. Registered fluxes were systematically higher at the urban than at the sub-urban site. Chemical characterization allowed to estimate at 29% the proportion of these fibers being all synthetic (made with petrochemicals), or a mixture of natural and synthetic material. Extrapolation using weight and volume estimates of the collected fibers, allowed a rough estimation showing that between 3 and 10 tons of fibers are deposited by atmospheric fallout at the scale of the Parisian agglomeration every year (2500 km(2)). These results could serve the scientific community working on the different sources of microplastic in both continental and marine environments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Source identification of ambient PM 2.5 during summer inhalation exposure studies in Detroit, MI

NASA Astrophysics Data System (ADS)

Morishita, Masako; Keeler, Gerald J.; Wagner, James G.; Harkema, Jack R.

Particulate air pollution is associated with cardiopulmonary morbidity and mortality in heavily populated urban centers of the United States. Because ambient fine particulate matter (aerodynamic diameter ⩽2.5 μm; PM 2.5) is a complex mixture resulting from multiple sources and variable atmospheric conditions, it is difficult to identify specific components of PM 2.5 that are responsible for adverse health effects. During four consecutive summers from 2000 to 2003 we characterized the ambient gaseous and PM 2.5 air quality in an urban southwest Detroit community where childhood asthma hospitalization rates are more than twice the statewide average. Both integrated and continuous PM measurements together with gaseous air pollution measurements were performed using a mobile air research facility, AirCARE1, in which concurrent toxicological studies were being conducted. Chemical and physical characterizations of PM 2.5 as well as receptor modeling using positive matrix factorization (PMF) were completed. Results from PMF indicated that six major sources contributed to the observed ambient PM 2.5 mass during the summer months. Primary sources included (1) coal combustion/secondary sulfate aerosol, (2) motor vehicle/urban road dust, (3) municipal waste incinerators, (4) oil combustion/refineries, (5) sewage sludge incinerators, and (6) iron/steel manufacturing. Although the contribution of the coal/secondary sulfate aerosol source was greater than other factors, increased levels of urban PM 2.5 from local combustion sources were also observed. In addition to characterization of ambient PM 2.5 and their sources in southwest Detroit, this paper discusses possible associations of ambient PM 2.5 from local combustion sources, specifically incinerator and refinery emissions and the observed adverse health effects during the inhalation exposure campaigns.

Fine Particulate Matter Predictions Using High Resolution Aerosol Optical Depth (AOD) Retrievals

NASA Technical Reports Server (NTRS)

Chudnovsky, Alexandra A.; Koutrakis, Petros; Kloog, Itai; Melly, Steven; Nordio, Francesco; Lyapustin, Alexei; Wang, Jujie; Schwartz, Joel

2014-01-01

To date, spatial-temporal patterns of particulate matter (PM) within urban areas have primarily been examined using models. On the other hand, satellites extend spatial coverage but their spatial resolution is too coarse. In order to address this issue, here we report on spatial variability in PM levels derived from high 1 km resolution AOD product of Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm developed for MODIS satellite. We apply day-specific calibrations of AOD data to predict PM(sub 2.5) concentrations within the New England area of the United States. To improve the accuracy of our model, land use and meteorological variables were incorporated. We used inverse probability weighting (IPW) to account for nonrandom missingness of AOD and nested regions within days to capture spatial variation. With this approach we can control for the inherent day-to-day variability in the AOD-PM(sub 2.5) relationship, which depends on time-varying parameters such as particle optical properties, vertical and diurnal concentration profiles and ground surface reflectance among others. Out-of-sample "ten-fold" cross-validation was used to quantify the accuracy of model predictions. Our results show that the model-predicted PM(sub 2.5) mass concentrations are highly correlated with the actual observations, with out-of- sample R(sub 2) of 0.89. Furthermore, our study shows that the model captures the pollution levels along highways and many urban locations thereby extending our ability to investigate the spatial patterns of urban air quality, such as examining exposures in areas with high traffic. Our results also show high accuracy within the cities of Boston and New Haven thereby indicating that MAIAC data can be used to examine intra-urban exposure contrasts in PM(sub 2.5) levels.

Aryl hydrocarbon receptor-mediated activity of atmospheric particulate matter from an urban and a rural site in Switzerland

NASA Astrophysics Data System (ADS)

Wenger, Daniela; Gerecke, Andreas C.; Heeb, Norbert V.; Hueglin, Christoph; Seiler, Cornelia; Haag, Regula; Naegeli, Hanspeter; Zenobi, Renato

Atmospheric particulate matter (PM) is an air-suspended mixture of solid and liquid particles that vary in size, shape, and chemical composition. Long-term exposure to elevated concentrations of fine atmospheric particles is considered to pose a health threat to humans and animals. In this context, it has been hypothesized that toxic chemicals such as polycyclic aromatic hydrocarbons (PAHs) play an important role. Some PAHs are known to be carcinogenic and it has been shown that carcinogenic effects of PAHs are mediated by the aryl hydrocarbon receptor (AhR). In this study, PM1 was collected at a rural and an urban traffic site during an intense winter smog period, in which concentration of PM1 often exceeded 50 μg m -3. We applied an in vitro reporter gene assay (DR-CALUX) to detect and quantify PM1-associated chemicals that induce AhR-mediated gene expression. This activity was expressed as CALUX equivalents of 2,3,7,8-tetrachlorodibenzodioxin (PM-TCDD-CEQs). In addition, concentrations of PAHs in the PM1 extracts were determined using gas chromatography/high-resolution mass spectrometry. Concentrations of PM-TCDD-CEQs ranged from 10 to 85 pg m -3 and from 19 to 87 pg m -3 at the urban and rural site, respectively. By the use of known relative potency factors, the measured concentration of a PAH was converted into a PAH-TCDD-CEQ concentration. ΣPAH-TCDD-CEQ and PM-TCDD-CEQ were highly correlated at both sites ( r2 = 0.90 and 0.69). The calculated ΣPAH-TCDD-CEQs explain between 2% and 20% of the measured PM-TCDD-CEQs. Benzo[ k]fluoranthene was the most important PAH causing approximately 60% of the total ΣPAH-TCDD-CEQ activity. In contrast to NO, CO, PM10, and PM1, the concentration of PM-TCDD-CEQs showed no significant difference between the two sites. No indications were found that road traffic emissions caused elevated concentrations of PM-TCDD-CEQs at the urban traffic site.

Overview of Megacity Air Pollutant Emissions and Impacts

NASA Astrophysics Data System (ADS)

Kolb, C. E.

2013-05-01

The urban metabolism that characterizes major cities consumes very large qualities of humanly produced and/or processed food, fuel, water, electricity, construction materials and manufactured goods, as well as, naturally provided sunlight, precipitation and atmospheric oxygen. The resulting urban respiration exhalations add large quantities of trace gas and particulate matter pollutants to urban atmospheres. Key classes of urban primary air pollutants and their sources will be reviewed and important secondary pollutants identified. The impacts of these pollutants on urban and downwind regional inhabitants, ecosystems, and climate will be discussed. Challenges in quantifying the temporally and spatially resolved urban air pollutant emissions and secondary pollutant production rates will be identified and possible measurement strategies evaluated.

Trends of atmospheric black carbon concentration over the United Kingdom

NASA Astrophysics Data System (ADS)

Singh, Vikas; Ravindra, Khaiwal; Sahu, Lokesh; Sokhi, Ranjeet

2018-04-01

The continuous observations over a period of 7 years (2009-2016) available at 7 locations show declining trend of atmospheric BC in the UK. Among all the locations, the highest decrease of 8 ± 3 percent per year was observed at the Marylebone road in London. The detailed analysis performed at 21 locations during 2009-2011 shows that average annual mean atmospheric BC concentration were 0.45 ± 0.10, 1.47 ± 0.58, 1.34 ± 0.31, 1.83 ± 0.46 and 9.72 ± 0.78 μgm-3 at rural, suburban, urban background, urban centre and kerbside sites respectively. Around 1 μgm-3 of atmospheric BC could be attributed to urban emission, whereas traffic contributed up to 8 μg m-3 of atmospheric BC near busy roads. Seasonal pattern was also observed at all locations except rural and kerbside location, with maximum concentrations (1.2-4 μgm-3) in winter. Further, minimum concentrations (0.3-1.2 μgm-3) were observed in summer and similar concentrations in spring and fall. At suburban and urban background locations, similar diurnal pattern were observed with atmospheric BC concentration peaks (≈1.8 μg m-3) in the morning (around 9 a.m.) and evening (7-9 p.m.) rush hours, whereas minimum concentrations were during late night hours (peak at 5 a.m.) and the afternoon hours (peak at 2 p.m.). The urban centre values show a similar morning pattern (peak at 9 a.m.; concentration - 2.5 μgm-3) in relation to background locations but only a slight decrease in concentration in the afternoon which remained above 2 μgm-3 till midnight. It is concluded that the higher flow of traffic at urban centre locations results in higher atmospheric BC concentrations throughout the day. Comparison of weekday and weekend daily averaged atmospheric BC showed maximum concentrations on Friday, having minimum levels on Sunday. This study will help to refine the atmospheric BC emission inventories and provide data for air pollution and climate change models evaluation, which are used to formulate air pollution mitigation policies.

Size-resolved particulate water-soluble organic compounds in the urban, mountain and marine atmosphere

NASA Astrophysics Data System (ADS)

Wang, G.; Kawamura, K.; Xie, M.; Hu, S.; Zhou, B.; Li, J.; Cao, J.; An, Z.

2010-07-01

Primary (i.e., sugars and sugar alcohols) and secondary water-soluble organic compounds (WSOCs) (i.e., dicarboxylic acids and aromatic acids) were characterised on a molecular level in size-segregated aerosols from the urban and mountain atmosphere of China and from the marine atmosphere in the outflow region of East Asia. Levoglucosan is the most abundant WSOCs in the urban and mountain atmosphere, whose accumulated concentrations in all stages are 1-3 orders of magnitude higher than those of marine aerosols. In contrast, malic, succinic and phthalic acids are dominant in the marine aerosols, which are 3-6 times more abundant than levoglucosan. This suggests that a continuous formation of secondary organic aerosols is occurring in the marine atmosphere during the long-range transport of air mass from inland China to the North Pacific. Sugars and sugar-alcohols, except for levoglucosan, gave a bimodal size distribution in the urban and mountain areas, peaking at 0.7-1.1 μm and >3.3 μm, and a unimodal distribution in the marine region, peaking at >3.3 μm. In contrast, levoglucosan and all the secondary WSOCs, except for benzoic and azelaic acids, showed a unimodal size distribution with a peak at 0.7-1.1 μm. Geometric mean diameters (GMDs) of the WSOCs in fine particles (<2.1 μm) at the urban site are larger in winter than in spring, due to an enhanced coagulation effect under the development of an inversion layer. However, GMDs of levoglucosan and most of the secondary WSOCs in the coarse mode are larger in the mountain and marine air and smaller in the urban air. This is most likely caused by an enhanced hygroscopic growth due to the high humidity of the mountain and marine atmosphere.

Direct identification of trace metals in fine and ultrafine particles in the Detroit urban atmosphere.

PubMed

Utsunomiya, Satoshi; Jensen, Keld A; Keeler, Gerald J; Ewing, Rodney C

2004-04-15

Exposure to airborne particulates containing low concentrations of heavy metals, such as Pb, As, and Se, may have serious health effects. However, little is known about the speciation and particle size of these airborne metals. Fine- and ultrafine particles with heavy metals in aerosol samples from the Detroit urban area, Michigan, were examined in detail to investigate metal concentrations and speciation. The characterization of individual particles was completed using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) combined with conventional high-resolution TEM techniques. The trace elements, Pb, As, La, Ce, Sr, Zn, Cr, Se, Sn, Y, Zr, Au, and Ag, were detected, and the elemental distributions were mapped in situ atthe nanoscale. The crystal structures of the particles containing Pb, Sr, Zn, and Au were determined from their electron diffraction patterns. Based on the characterization of the representative trace element particles, the potential health effects are discussed. Most of the trace element particles detected in this study were within a range of 0.01-1.0 microm in size, which has the longest atmospheric residence time (approximately 100 days). Increased chemical reactivity owing to the size of nanoparticles may be expected for most of the trace metal particles observed.

Megacities and large urban agglomerations in the coastal zone: interactions between atmosphere, land, and marine ecosystems.

PubMed

von Glasow, Roland; Jickells, Tim D; Baklanov, Alexander; Carmichael, Gregory R; Church, Tom M; Gallardo, Laura; Hughes, Claire; Kanakidou, Maria; Liss, Peter S; Mee, Laurence; Raine, Robin; Ramachandran, Purvaja; Ramesh, R; Sundseth, Kyrre; Tsunogai, Urumu; Uematsu, Mitsuo; Zhu, Tong

2013-02-01

Megacities are not only important drivers for socio-economic development but also sources of environmental challenges. Many megacities and large urban agglomerations are located in the coastal zone where land, atmosphere, and ocean meet, posing multiple environmental challenges which we consider here. The atmospheric flow around megacities is complicated by urban heat island effects and topographic flows and sea breezes and influences air pollution and human health. The outflow of polluted air over the ocean perturbs biogeochemical processes. Contaminant inputs can damage downstream coastal zone ecosystem function and resources including fisheries, induce harmful algal blooms and feedback to the atmosphere via marine emissions. The scale of influence of megacities in the coastal zone is hundreds to thousands of kilometers in the atmosphere and tens to hundreds of kilometers in the ocean. We list research needs to further our understanding of coastal megacities with the ultimate aim to improve their environmental management.

Association of long-term PM2.5 exposure with mortality using different air pollution exposure models: impacts in rural and urban California.

PubMed

Garcia, Cynthia A; Yap, Poh-Sin; Park, Hye-Youn; Weller, Barbara L

2016-01-01

Most PM2.5-associated mortality studies are not conducted in rural areas where mortality rates may differ when population characteristics, health care access, and PM2.5 composition differ. PM2.5-associated mortality was investigated in the elderly residing in rural-urban zip codes. Exposure (2000-2006) was estimated using different models and Poisson regression was performed using 2006 mortality data. PM2.5 models estimated comparable exposures, although subtle differences were observed in rate ratios (RR) within areas by health outcomes. Cardiovascular disease (CVD), ischemic heart disease (IHD), and cardiopulmonary disease (CPD), mortality was significantly associated with rural, urban, and statewide chronic PM2.5 exposures. We observed larger effect sizes in RRs for CVD, CPD, and all-cause (AC) with similar sizes for IHD mortality in rural areas compared to urban areas. PM2.5 was significantly associated with AC mortality in rural areas and statewide; however, in urban areas, only the most restrictive exposure model showed an association. Given the results seen, future mortality studies should consider adjusting for differences with rural-urban variables.

Aquatic exposures of chemical mixtures in urban environments: Approaches to impact assessment.

PubMed

de Zwart, Dick; Adams, William; Galay Burgos, Malyka; Hollender, Juliane; Junghans, Marion; Merrington, Graham; Muir, Derek; Parkerton, Thomas; De Schamphelaere, Karel A C; Whale, Graham; Williams, Richard

2018-03-01

Urban regions of the world are expanding rapidly, placing additional stress on water resources. Urban water bodies serve many purposes, from washing and sources of drinking water to transport and conduits for storm drainage and effluent discharge. These water bodies receive chemical emissions arising from either single or multiple point sources, diffuse sources which can be continuous, intermittent, or seasonal. Thus, aquatic organisms in these water bodies are exposed to temporally and compositionally variable mixtures. We have delineated source-specific signatures of these mixtures for diffuse urban runoff and urban point source exposure scenarios to support risk assessment and management of these mixtures. The first step in a tiered approach to assessing chemical exposure has been developed based on the event mean concentration concept, with chemical concentrations in runoff defined by volumes of water leaving each surface and the chemical exposure mixture profiles for different urban scenarios. Although generalizations can be made about the chemical composition of urban sources and event mean exposure predictions for initial prioritization, such modeling needs to be complemented with biological monitoring data. It is highly unlikely that the current paradigm of routine regulatory chemical monitoring alone will provide a realistic appraisal of urban aquatic chemical mixture exposures. Future consideration is also needed of the role of nonchemical stressors in such highly modified urban water bodies. Environ Toxicol Chem 2018;37:703-714. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

The impacts of rapid land use changes on regional climate, air quality and atmospheric sensitivities to emissions

NASA Astrophysics Data System (ADS)

Yim, S. H. L.; Wong, M.; Wang, Y.; Chan, A.

2016-12-01

The Pearl River Delta region has undergone a rapid urbanization in recent several decades. Literature has found significant impacts on climate and air quality. Previous studies however mainly investigated the impacts on climate and ozone concentration in a relatively short time period. None of them investigated the monthly variation in impacts on ozone (O3) and fine particulate matters (PM2.5), and the atmospheric sensitivity to emissions, which are particularly important for atmospheric scientists and policy makers. In this study, we used the state-of-the-art atmospheric regional models with the technique of high-order decoupled direct method to quantify the impacts of urbanization on not only the regional climate and O3 concentration but also the O3 sensitivities to emissions of nitrogen oxides and volatile organic compound. Our preliminary results show that the urbanization shifts the energy budget from latent heat to sensible heat and ground heat storage. These changes cause an increase in ground level temperature and planetary boundary layer with a maximum annual change of 1.7ºC and 330m, respectively, and a reduction of relative humidity and wind speed up to 9.6% and 0.5m/s, respectively. Such changes are favorable to air pollution. Compared to the two land-use scenarios, we found that O3 increases by 14.2%, while PM2.5 decreases by 16.9% in urban areas. Due to urbanization, the O3 sensitivities to nitrogen oxides (NOx) and volatile organic compound (VOC) change by 2.4% and 47.5%, respectively. This indicates that the atmospheric response in the region tends to be more sensitive to emission changes after urbanization. Our findings pinpoint that urbanization can significantly affect not only the regional climate and air quality but also the atmospheric responses to emission changes, highlighting the significant interactions between land-use policies, and climate and air quality policies.

Scanning Electron Microanalysis and Analytical Challenges of Mapping Elements in Urban Atmospheric Particles

EPA Science Inventory

Elemental mapping with energy-dispersive X-ray spectroscopy (EDX) associated with scanning electron microscopy is highly useful for studying internally mixed atmospheric particles. Presented is a study of individual particles from urban airsheds and the analytical challenges in q...

SEMI-VOLATILE SECONDARY AEROSOLS IN URBAN ATMOSPHERES: MEETING A MEASURED CHALLENGE

EPA Science Inventory

This presentation compares the results from various particle measurement methods as they relate to semi-volatile secondary aerosols in urban atmospheres. The methods include the PM2.5 Federal Reference Method; Particle Concentrator - BYU Organic Sampling System (PC-BOSS); the Re...

Identification of Major Sources of Atmospheric NH3 in an Urban Environment in Northern China During Wintertime.

PubMed

Teng, Xiaolin; Hu, Qingjing; Zhang, Leiming; Qi, Jiajia; Shi, Jinhui; Xie, Huan; Gao, Huiwang; Yao, Xiaohong

2017-06-20

To assess the relative contributions of traffic emission and other potential sources to high levels of atmospheric ammonia (NH 3 ) in urban areas in the wintertime, atmospheric NH 3 and related pollutants were measured at an urban site, ∼300 m from a major traffic road, in northern China in November and December 2015. Hourly average NH 3 varied from 0.3 to 10.8 ppb with an average of 2.4 ppb during the campaign. Contrary to the common perspective in literature, traffic emission was demonstrated to be a negligible contributor to atmospheric NH 3 . Atmospheric NH 3 correlated well with ambient water vapor during many time periods lasting from tens of hours to several days, implying NH 3 released from water evaporation is an important source. Emissions from local green space inside the urban areas were identified to significantly contribute to the observed atmospheric NH 3 during ∼60% of the sampling times. Evaporation of predeposited NH x through wet precipitation combined with emissions from local green space likely caused the spikes of atmospheric NH 3 mostly occurring 1-4 h after morning rush hours or after and during slight shower events. There are still ∼30% of the data samples with appreciable NH 3 level for which major contributors are yet to be identified.

Urban–rural differentials in the factors associated with exposure to second-hand smoke in India

PubMed Central

Singh, Akansha; Sahoo, Namita

2013-01-01

Objectives This study aims to investigate the role of different factors associated with exposure to second-hand smoke (SHS) in the workplace and home in the urban and rural areas of India. Design Secondary analysis of the data from the Global Adult Tobacco Survey conducted in 2009–2010. Setting and participants Data were analysed from 32 738 rural and 23 202 urban non-smokers at home and 4809 rural and 6227 urban non-smokers in the workplace in India. Outcomes and methods We used two measures of SHS: exposure to SHS at home and exposure to SHS in the workplace. SHS exposure at home is estimated for non-smokers who reported anyone smoking inside his/her home. Exposure to SHS in the workplace is estimated for non-smokers who reported anyone smoking in the workplace in the past 30 days before the survey. Statistical techniques such as χ2 test, logistic regression and discriminant function analysis were used. Results The results showed that SHS exposure in the workplace and home is higher in the rural areas than in the urban areas. As compared with men, women are significantly more likely to be exposed to SHS at home (OR=1.20, 95% CI 1.10 to 1.30) in the rural areas, and less likely at the workplace in the urban areas (OR=0.49, 95% CI 0.40 to 0.59). Education and region are significant predictors of exposure levels to SHS at home and the workplace in the rural and urban areas. The knowledge of number of smoking-related hazards significantly discriminates the SHS exposure in the rural workplace. SHS exposure at home is most affected by region in the rural areas and education in the urban areas. Conclusions The factors which affect SHS exposure differ in the rural and urban areas of India. The study concludes that the risk of getting exposed to SHS at home and the workplace among non-smokers is higher in the rural areas of the country. PMID:24282245

Chemical, optical and radiative characteristics of aerosols during haze episodes of winter in the North China Plain

NASA Astrophysics Data System (ADS)

Ding, Jing; Zhang, Yufen; Han, Suqin; Xiao, Zhimei; Wang, Jiao; Feng, Yinchang

2018-05-01

Aerosol and water vapor radiative forcings, shortwave atmospheric heating rates and longwave atmospheric cooling rates were determined based on in situ physical and chemical measurements of aerosol, associated with the Mie theory and a radiative transfer model, LOWTRAN7, during the two haze episodes in the winter of 2013 in Tianjin, China. The aerosol types considered in LOWTRAN7 included rural, urban, marine, desert and custom aerosols. The default ratio of the absorption coefficient to the extinction coefficient for urban aerosol in LOWTRAN7 was approximately double of those found in this work, implying the weaker absorption ability of aerosols in the North China Plain (NCP). Moreover, the aerosol is assumed to be evenly distributed below 1 km of planetary boundary layer (PBL) on hazy days in LOWTRAN7. If the default urban aerosol optical properties and extinction profile in LOWTRAN7 is employed directly, a larger energy imbalance between the atmosphere and surface is generated and the warming effect of the aerosol is magnified. Hence, modified urban aerosol optical properties were established to replace the corresponding parameters' database in LOWTRAN7. The aerosol extinction profiles were obtained based on a 255-m meteorological tower and observed results from the studies about Tianjin. In the NCP, the aerosol had little impact on atmospheric counter radiation. The water vapor is the crucial factor that affects atmospheric counter radiation. Both modified high shortwave heating rates and longwave cooling rates occur near the surface due to the abundance of aerosol and water vapor. The modified net atmospheric heating rate near the surface is 1.2 K d-1 on hazy days and 0.3 K d-1 on non-hazy days. Compared with the default urban aerosol optical properties and its vertical distribution in LOWTRAN7, the feedback effect of the modified urban aerosol on the boundary layer may not necessarily result in a stable lower atmosphere, but depends on the aerosol light absorption ability and its vertical distribution.

Using Sediment Records to Reconstruct Historical Inputs Combustion-Derived Contaminants to Urban Airsheds/Watersheds: A Case Study From the Puget Sound

NASA Astrophysics Data System (ADS)

Louchouarn, P. P.; Kuo, L.; Brandenberger, J.; Marcantonio, F.; Wade, T. L.; Crecelius, E.; Gobeil, C.

2008-12-01

Urban centers are major sources of combustion-derived particulate matter (e.g. black carbon (BC), polycyclic aromatic hydrocarbons (PAH), anhydrosugars) and volatile organic compounds to the atmosphere. Evidence is mounting that atmospheric emissions from combustion sources remain major contributors to air pollution of urban systems. For example, recent historical reconstructions of depositional fluxes for pyrogenic PAHs close to urban systems have shown an unanticipated reversal in the trends of decreasing emissions initiated during the mid-20th Century. Here we compare a series of historical reconstructions of combustion emission in urban and rural airsheds over the last century using sedimentary records. A complex suite of combustion proxies (BC, PAHs, anhydrosugars, stable lead concentrations and isotope signatures) assisted in elucidating major changes in the type of atmospheric aerosols originating from specific processes (i.e. biomass burning vs. fossil fuel combustion) or fuel sources (wood vs. coal vs. oil). In all studied locations, coal continues to be a major source of combustion-derived aerosols since the early 20th Century. Recently, however, oil and biomass combustion have become substantial additional sources of atmospheric contamination. In the Puget Sound basin, along the Pacific Northwest region of the U.S., rural locations not impacted by direct point sources of contamination have helped assess the influence of catalytic converters on concentrations of oil-derived PAH and lead inputs since the early 1970s. Although atmospheric deposition of lead has continued to drop since the introduction of catalytic converters and ban on leaded gasoline, PAH inputs have "rebounded" in the last decade. A similar steady and recent rise in PAH accumulations in urban systems has been ascribed to continued urban sprawl and increasing vehicular traffic. In the U.S., automotive emissions, whether from gasoline or diesel combustion, are becoming a major source of combustion-derived PM and BC to the atmosphere and have started to replace coal as the major source in some surficial reservoirs. This increased urban influence of gasoline and diesel combustion on BC emissions was also observed in Europe both from model estimates as well as from measured fluxes in recent lake sediments.

ATMOSPHERIC MERCURY IN THE LAKE MICHIGAN BASIN: INFLUENCE OF THE CHICAGO/GARY URBAN AREA

EPA Science Inventory

The relative importance of the Chicago/Gay urban area was investigated to determine its impact on atmospheric mercury (Hg) concentrations and wet deposition in the Lake Michigan basin. Event wet-only precipitation, total particulate, and vapor phase samples were collected for ...

Eutrophication of an Urban Forest Ecosystem: Causes and Effects

NASA Astrophysics Data System (ADS)

Bednova, O. V.; Kuznetsov, V. A.; Tarasova, N. P.

2018-01-01

The combined use of methods of passive dosimetry of the status of atmospheric air, phytoindication, and cartographic visualization of data made it possible to elaborate and substantiate approaches to evaluation of the effect of atmospheric air contamination on the eutrophication of forest ecosystems under urban conditions.

Atmospheric particulate matter intercepted by moss-bags: Relations to moss trace element uptake and land use.

PubMed

Di Palma, Anna; Capozzi, Fiore; Spagnuolo, Valeria; Giordano, Simonetta; Adamo, Paola

2017-06-01

Particulate matter has to be constantly monitored because it is an important atmospheric transport form of potentially harmful contaminants. The cost-effective method of the moss-bags can be employed to evaluate both loads and chemical composition of PM. PM entrapped by the moss Pseudoscleropodium purum exposed in bags in 9 European sites was characterized for number, size and chemical composition by SEM/EDX. Moreover, moss elemental uptake of 53 elements including rare earth elements was estimated by ICP-MS analysis. All above was aimed to find possible relations between PM profile and moss uptake and to find out eventual element markers of the different land use (i.e. agricultural, urban, industrial) of the selected sites. After exposure, about 12,000 particles, mostly within the inhalable fraction, were counted on P. purum leaves; their number generally increased from the agricultural sites to the urban and industrial ones. ICP analysis indicated that twenty-three elements were significantly accumulated by mosses with different element profile according to the various land uses. The PM from agricultural sites were mainly made of natural/crustal elements or derived from rural activities. Industrial-related PM covered a wider range of sources, from those linked to specific industrial activities, to those related to manufacturing processes or use of heavy-duty vehicles. This study indicates a close association between PM amount and moss element-uptake, which increases in parallel with PM amount. Precious metals and REEs may constitute novel markers of air pollution in urban and agricultural sites, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

CO2 dispersion modelling over Paris region within the CO2-MEGAPARIS project

NASA Astrophysics Data System (ADS)

Lac, C.; Donnelly, R. P.; Masson, V.; Pal, S.; Donier, S.; Queguiner, S.; Tanguy, G.; Ammoura, L.; Xueref-Remy, I.

2012-10-01

Accurate simulation of the spatial and temporal variability of tracer mixing ratios over urban areas is challenging, but essential in order to utilize CO2 measurements in an atmospheric inverse framework to better estimate regional CO2 fluxes. This study investigates the ability of a high-resolution model to simulate meteorological and CO2 fields around Paris agglomeration, during the March field campaign of the CO2-MEGAPARIS project. The mesoscale atmospheric model Meso-NH, running at 2 km horizontal resolution, is coupled with the Town-Energy Balance (TEB) urban canopy scheme and with the Interactions between Soil, Biosphere and Atmosphere CO2-reactive (ISBA-A-gs) surface scheme, allowing a full interaction of CO2 between the surface and the atmosphere. Statistical scores show a good representation of the Urban Heat Island (UHI) and urban-rural contrasts. Boundary layer heights (BLH) at urban, sub-urban and rural sites are well captured, especially the onset time of the BLH increase and its growth rate in the morning, that are essential for tall tower CO2 observatories. Only nocturnal BLH at sub-urban sites are slightly underestimated a few nights, with a bias less than 50 m. At Eiffel tower, the observed spikes of CO2 maxima occur every morning exactly at the time at which the Atmospheric Boundary Layer (ABL) growth reaches the measurement height. The timing of the CO2 cycle is well captured by the model, with only small biases on CO2 concentrations, mainly linked to the misrepresentation of anthropogenic emissions, as the Eiffel site is at the heart of trafic emission sources. At sub-urban ground stations, CO2 measurements exhibit maxima at the beginning and at the end of each night, when the ABL is fully contracted, with a very strong spatio-temporal variability. The CO2 cycle at these sites is generally well reproduced by the model, even if some biases on the nocturnal maxima appear in the Paris plume parly due to small errors on the vertical transport, or in the vicinity of airports due to small errors on the horizontal transport (wind direction). A sensitivity test without urban parameterisation removes UHI and underpredicts nighttime BLH over urban and sub-urban sites, leading to large overestimation of nocturnal CO2 concentration at the sub-urban sites. The agreement of daytime and nighttime BLH and CO2 predictions of the reference simulation over Paris agglomeration demonstrates the potential of using the meso-scale system on urban and sub-urban area in the context of inverse modelling.

Inter-compartmental transport of organophosphate and pyrethroid pesticides in South China: implications for a regional risk assessment.

PubMed

Li, Huizhen; Wei, Yanli; Lydy, Michael J; You, Jing

2014-07-01

The dynamic flux of an organophosphate and four pyrethroid pesticides was determined in an air-(soil)-water-sediment system based on monitoring data from Guangzhou, China. The total air-water flux, including air-water gaseous exchange and atmospheric deposition, showed deposition from air to water for chlorpyrifos, bifenthrin and cypermethrin, but volatilization for lambda-cyhalothrin and permethrin. The transport of the pesticides from overlying water to sediment suggested that sediment acted as a sink for the pesticides. Additionally, distinct annual atmospheric depositional fluxes between legacy and current-use pesticides suggested the role of consumer usage in their transport throughout the system. Finally, pesticide toxicity was estimated from annual air-water-sediment flux within an urban stream in Guangzhou. A dynamic flux-based risk assessment indicated that inter-compartmental transport of chlorpyrifos decreased its atmospheric exposure, but had little influence on its aquatic toxicity. Instead, water-to-sediment transport of pyrethroids increased their sediment toxicity, which was supported by previously reported toxicity data. Copyright © 2014 Elsevier Ltd. All rights reserved.

Source and chemical species characterization of PM10 and human health risk assessment of semi-urban, urban and industrial areas of West Bengal, India.

PubMed

Ghosh, Suraj; Rabha, Rumi; Chowdhury, Mallika; Padhy, Pratap Kumar

2018-09-01

Levels of particulate matter of size ten micron (PM 10 ) in outdoor air, potential PM 10 -bound seven metals - manganese, zinc, cadmium, lead, copper, nickel and cobalt - and twelve water-soluble organic and inorganic ionic components - fluoride, acetate, chloride, nitrite, bromide, nitrate, phosphate, sulfate, oxalate, sodium, potassium and calcium - were investigated during two different season. Atmospheric PM 10 samples were collected concurrently from three different sites, i.e., Durgapur (Industrial), Berhampore (Urban) and Bolpur (Semi-urban), West Bengal, India, during summer (April-June 2014) and winter (December 2014-February 2015). Average PM 10 levels were found to be in the range of 189.58-219.96 μg/m 3 at the semi-urban site, 293.41-324.27 μg/m 3 at the urban site and 316.93-344.69 μg/m 3 at the industrial site during summer and winter season respectively. Data on metals and water soluble ions were analyzed statistically (Principal Component Analysis and Factor Analysis) for their source identification and apportionment in the study areas. Principle component analysis models, from three different sites, identified four different factors which share common sources, viz., soil & road re-suspension, motor vehicle and traffic, waste dumping, biomass aerosols, and construction. The pollution load and health risk assessments of selected metals were undertaken in three different sites, within children and adults of the study areas, and were found to be within the safe range. Furthermore, an attempt has also been made to provide basic information on pollution, their sources and exposure pathways for humans in the vicinity of semi-urban, urban and industrial regions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Soil-water interactions: implications for the sustainability of urban areas

NASA Astrophysics Data System (ADS)

Ferreira, António J. D.; Ferreira, Carla S. S.; Walsh, Rory P. D.

2015-04-01

Cities have become recently the home for more than half of the world's population. Cities are often seen as ecological systems just a short step away from collapse [Newman 2006]. Being a human construction, cities disrupt the natural cycles and the patterns of temporal and spatial distribution of environmental and ecological processes. Urbanization produces ruptures in biota, water, energy and nutrients connectivity that can lead to an enhanced exposure to disruptive events that hamper the wellbeing and the resilience of urban communities in a global change context. And yet, mankind can't give up of these structures one step away from collapse. In this paper we visit the ongoing research at the Ribeira dos Covões peri-urban catchment, as the basis to discuss several important processes and relations in the water-soil interface: A] the impact of the build environment and consequently the increase of the impervious area on the generation and magnitude of hydrological processes at different scales, the impact on flash flood risk and the mitigation approaches. B] the pollutant sources transport and fade in urban areas, with particular emphasis in the role of vegetation and soils in the transmission of pollutants from the atmosphere to the soil and to the water processes. C] the use and the environmental services of the urban ecosystems (where the relations of water, soil and vegetation have a dominate role) to promote a better risk and resources governance. D] the special issue of urban agriculture, where all the promises of sustainability and threats to wellbeing interact, and where the soil and water relations in urban areas are more significant and have the widest and deepest implications.

Association between prenatal exposure to traffic-related air pollution and preterm birth in the PELAGIE mother-child cohort, Brittany, France. Does the urban-rural context matter?

PubMed

Bertin, Mélanie; Chevrier, Cécile; Serrano, Tania; Monfort, Christine; Rouget, Florence; Cordier, Sylvaine; Viel, Jean-François

2015-10-01

Evidence has accumulated that exposure to ambient air pollution during pregnancy may influence preterm birth (PTB) in urban settings. Conversely, this relation has barely been investigated in rural areas where individual characteristics (demographic, socioeconomic, and psychosocial factors) and environmental co-exposures may differ. We examined the association between prenatal exposure to traffic-related air pollution and PTB among pregnant women from the PELAGIE mother-child cohort (Brittany, France, 2002-2006) living in urban (n=1550) and rural (n=959) settings. Women's residences were classified as either urban or rural according to the French census bureau rural-urban definitions. Nitrogen dioxide (NO2) concentrations at home addresses were estimated from adjusted land-use regression models as a marker of traffic-related pollution. Associations between NO2 concentrations and PTB were assessed with logistic regression models. Prevalence of PTB was similar among women living in urban (3.2%) and in rural (3.5%) settings. More positive socioeconomic characteristics and health behaviors but more single-parent families were observed among urban women. NO2 exposure averaged 20.8±6.6 µg m(-3) for women residing in urban areas and 18.8±5.6 µg m(-3) for their rural counterparts. A statistically significant increased risk of PTB was observed among women exposed to NO2 concentrations ≥16.4 µg m(-3) and residing in urban areas but not among their rural counterparts. The results of this study, conducted in a region with interspersed urban-rural areas, are in line with previous findings suggesting an increased risk of PTB associated with higher NO2 concentrations for women living in urban areas. The absence of association among their rural counterparts for whom exposure levels were similar suggests that environmental mixtures and psychosocial inequalities might play a role in this heterogeneity. Copyright © 2015 Elsevier Inc. All rights reserved.

Spectral solar attenuation due to aerosol loading over an urban area in India

NASA Astrophysics Data System (ADS)

Latha, K. Madhavi; Badarinath, K. V. S.

2005-06-01

Anthropogenic activities in urban areas are sources for atmospheric aerosols and are increasing due to population explosion and migration. Many large cities in the developing world are presently plagued by high levels of atmospheric pollution and long-term effect of urban aerosol on climate is an important topic. In the present study, ground-based measurements of solar irradiance, aerosol loading and black carbon (BC) aerosol concentration have been analyzed during different aerosol loading conditions during 2003 over an urban environment. BC aerosols concentration has been observed to be enhanced during high aerosol optical depth day suggesting influence of local anthropogenic activities. The analysis of wind fields over the study area during the measurement period is from north with continental air mass prevailing over the region. Spectral measurements of solar irradiance exhibited variations based on aerosol loading in urban atmosphere. Relative attenuations caused by aerosols have been found to be of the order of 21% and 17% on the irradiance on visible and near infrared respectively.

Active Sphagnum girgensohnii Russow Moss Biomonitoring of an Industrial Site in Romania: Temporal Variation in the Elemental Content.

PubMed

Culicov, Otilia A; Zinicovscaia, Inga; Duliu, O G

2016-05-01

The moss-bag transplant technique was used to investigate the kinetics of the accumulation of 38 elements in Sphagnum girgensohni moss samples in the highly polluted municipality of Baia Mare, Romania. The moss samples collected from the unpolluted Vitosha Mountain Natural Reserve, Bulgaria, were analyzed after 1, 2, 3, and 4 months of exposure, respectively. The ANOVA method was used to assay the statistical significance of the observed changes in elemental content, as determined by neutron activation analysis. The content of Zn, Se, As, Ag, Cd, and Sb increased steadily, while that of physiologically active K and Cl, as well as Rb and Cs, decreased exponentially. The study showed that an adequate application of the moss transplant technique in an urban environment should consider the exposure time as a critical parameter, since particular elements are depleted in the moss at sites with high atmospheric loading of metals.

The dust retention capacities of urban vegetation-a case study of Guangzhou, South China.

PubMed

Liu, Lu; Guan, Dongsheng; Peart, M R; Wang, Gang; Zhang, Hui; Li, Zhiwei

2013-09-01

Urban vegetation increasingly plays an important role in the improvement of the urban atmospheric environment. This paper deals with the dust retention capacities of four urban tree species (Ficus virens var. sublanceolata, Ficus microcarpa, Bauhinia blakeana, and Mangifera indica Linn) in Guangzhou. The dust-retaining capacities of four tree species are studied under different pollution intensities and for different seasons. Remote sensing imagery was used to estimate the total aboveground urban vegetation biomass in different functional areas of urban Guangzhou, information that was then used to estimate the dust-retaining capacities of the different functional areas and the total removal of airborne particulates in urban Guangzhou by foliage. The results showed that urban vegetation can remove dust from the atmosphere thereby improving air quality. The major findings are that dust retention, or capture, vary between the four species of tree studied; it also varied between season and between types of urban functional area, namely industrial, commercial/road traffic, residential, and clean areas. Dust accumulation over time was also studied and reached a maximum, and saturation, after about 24 days. The overall aboveground biomass of urban vegetation in Guangzhou was estimated to be 52.0 × 10(5) t, its total leaf area 459.01 km(2), and the dust-retaining capacity was calculated at 8012.89 t per year. The present study demonstrated that the foliage of tree species used in urban greening make a substantial contribution to atmospheric dust removal and retention in urban Guangzhou.

Kinetic study of phytotoxicity induced by foliar lead uptake for vegetables exposed to fine particles and implications for sustainable urban agriculture.

PubMed

Xiong, TianTian; Austruy, Annabelle; Pierart, Antoine; Shahid, Muhammad; Schreck, Eva; Mombo, Stéphane; Dumat, Camille

2016-08-01

At the global scale, foliar metal transfer occurs for consumed vegetables cultivated in numerous urban or industrial areas with a polluted atmosphere. However, the kinetics of metal uptake, translocation and involved phytotoxicity was never jointly studied with vegetables exposed to micronic and sub-micronic particles (PM). Different leafy vegetables (lettuces and cabbages) cultivated in RHIZOtest® devices were, therefore, exposed in a greenhouse for 5, 10 and 15days to various PbO PM doses. The kinetics of transfer and phytotoxicity was assessed in relation to lead concentration and exposure duration. A significant Pb accumulation in leaves (up to 7392mg/kg dry weight (DW) in lettuce) with translocation to roots was observed. Lead foliar exposure resulted in significant phytotoxicity, lipid composition change, a decrease of plant shoot growth (up to 68.2% in lettuce) and net photosynthesis (up to 58% in lettuce). The phytotoxicity results indicated plant adaptation to Pb and a higher sensitivity of lettuce in comparison with cabbage. Air quality needs, therefore, to be considered for the health and quality of vegetables grown in polluted areas, such as certain megacities (in China, Pakistan, Europe, etc.) and furthermore, to assess the health risks associated with their consumption. Copyright © 2016. Published by Elsevier B.V.

Secondary Organic Aerosol Formation and Aging in a Flow Reactor in the Forested Southeast US during SOAS

NASA Astrophysics Data System (ADS)

Hu, W.; Palm, B. B.; Hacker, L.; Campuzano Jost, P.; Day, D. A.; de Sá, S. S.; Ayres, B. R.; Draper, D.; Fry, J.; Ortega, A. M.; Kiendler-Scharr, A.; Pajunoja, A.; Virtanen, A.; Krechmer, J.; Canagaratna, M. R.; Thompson, S.; Yatavelli, R. L. N.; Stark, H.; Worsnop, D. R.; Martin, S. T.; Farmer, D.; Brown, S. S.; Jimenez, J. L.

2015-12-01

A major field campaign (Southern Oxidant and Aerosol Study, SOAS) was conducted in summer 2013 in a forested area in Centreville Supersite, AL (SEARCH network) in the southeast U.S. To investigate secondary organic aerosol (SOA) formation from biogenic volatile organic compounds (BVOCs), 3 oxidation flow reactors (OFR) were used to expose ambient air to oxidants and their output was analyzed by state-of-the-art gas and aerosol instruments including a High-Resolution Aerosol Mass Spectrometer (HR-AMS), a HR Proton-Transfer Reaction Time-of-Flight Mass Spectrometer (PTR-TOFMS), and Two HR-TOF Chemical Ionization Mass Spectrometers (HRToF-CIMS). Ambient air was exposed 24/7 to variable concentrations of each of the 3 main atmospheric oxidants (OH, NO3 radicals and O3) to investigate the oxidation of BVOCs (including isoprene derived epoxydiols, IEPOX) and SOA formation and aging. Effective OH exposures up to 1×1013 molec cm-3 s were achieved, equivalent to over a month of aging in the atmosphere. Multiple oxidation products from isoprene and monoterpenes including small gas-phase acids were observed in OH OFR. High SOA formation of up to 12 μg m-3 above ambient concentrations of 5 μg m-3 was observed under intermediate OH exposures, while very high OH exposures led to destruction of ~30% of ambient OA, indicating shifting contributions of functionalization vs. fragmentation, consistent with results from urban and terpene-dominated environments. The highest SOA enhancements were 3-4 times higher than ambient OA. More SOA is typically formed during nighttime when terpenes are higher and photochemistry is absent, and less during daytime when isoprene is higher, although the IEPOX pathway is suppressed in the OFR. SOA is also observed after exposure of ambient air to O3 or NO3, although the amounts and oxidation levels were lower than for OH. Formation of organic nitrates in the NO3 reaction will also be discussed.A major field campaign (Southern Oxidant and Aerosol Study, SOAS) was conducted in summer 2013 in a forested area in Centreville Supersite, AL (SEARCH network) in the southeast U.S. To investigate secondary organic aerosol (SOA) formation from biogenic volatile organic compounds (BVOCs), 3 oxidation flow reactors (OFR) were used to expose ambient air to oxidants and their output was analyzed by state-of-the-art gas and aerosol instruments including a High-Resolution Aerosol Mass Spectrometer (HR-AMS), a HR Proton-Transfer Reaction Time-of-Flight Mass Spectrometer (PTR-TOFMS), and two HR-TOF Chemical Ionization Mass Spectrometers (HRToF-CIMS). Ambient air was exposed 24/7 to variable concentrations of each of the 3 main atmospheric oxidants (OH, NO3 radicals and O3) to investigate the oxidation of BVOCs (including ambient isoprene-derived epoxydiols, IEPOX) and SOA formation and aging. Effective OH exposures up to 1×1013 molec cm-3 s were achieved, equivalent to over a month of aging in the atmosphere. Multiple oxidation products from isoprene and monoterpenes including small gas-phase acids were observed in OH OFR. High SOA formation of up to 12 μg m-3 above ambient concentrations of 5 μg m-3 was observed under intermediate OH exposures, while very high OH exposures led to destruction of ~30% of ambient OA, indicating shifting contributions of functionalization vs. fragmentation, consistent with results from urban and terpene-dominated environments. The highest SOA enhancements were 3-4 times higher than ambient OA. More SOA is typically formed during nighttime when terpenes are higher and photochemistry is absent, and less during daytime when isoprene is higher, although the IEPOX pathway is suppressed in the OFR. SOA is also observed after exposure of ambient air to O3 or NO3, although the amounts and oxidation levels were lower than for OH. Formation of organic nitrates in the NO3 reaction will also be discussed.

Impact of urban atmospheric pollution on coronary disease.

PubMed

Maitre, Anne; Bonneterre, Vincent; Huillard, Laurent; Sabatier, Philippe; de Gaudemaris, Régis

2006-10-01

Recent epidemiological findings have suggested that urban atmospheric pollution may have adverse effects on the cardiovascular system as well as on the respiratory system. We carried out an exhaustive search of published studies investigating links between coronary heart disease and urban atmospheric pollution. The review was conducted on cited articles published between 1994 and 2005 and whose main objective was to measure the risk of ischaemic heart diseases related to urban pollution. Of the 236 references identified, 46 epidemiological studies were selected for analysis on the basis of pre-defined criteria. The studies were analysed according to short-term effects (time series and case-crossover designs) and long-term effects (case-control and cohort studies). A link between coronary heart disease and at least one of the pollutants studied (PM10, O3, NOx, CO, SO2) emerged in 40 publications. Particulate matter, nitrogen oxides, and carbon monoxide were the pollutants most often linked with coronary heart disease. The association was inconstant for O3. Although the mean mortality or morbidity risk related to urban atmospheric pollution is low compared with that associated with other better-known risk factors, its impact on health is nevertheless major because of the large number of people who are exposed. This exhaustive review supports the possibility that urban pollution is indeed an environmental cardiovascular risk factor and should be considered as such by the cardiologists.

Selected water-soluble organic compounds found in size-resolved aerosols collected from urban, mountain and marine atmospheres over East Asia

NASA Astrophysics Data System (ADS)

Wang, Gehui; Kawamura, Kimitaka; Xie, Mingjie; Hu, Shuyuan; Li, Jianjun; Zhou, Bianhong; Cao, Junji; An, Zhisheng

2011-07-01

Primary (i.e. sugars and sugar-alcohols) and secondary (i.e. carboxylic acids) water-soluble organic compounds (WSOCs) in size-segregated aerosols from the urban and mountain atmosphere of China and from the marine atmosphere in the outflow region of East Asia were characterized on a molecular level. Levoglucosan is the most abundant compound among the quantified WSOCs in the urban and mountain atmosphere, whose concentration at the urban site was 1-2 orders of magnitude higher than that at the mountain and marine sites. In contrast, malic, succinic and phthalic acids were dominant among the measured WSOCs at the marine site. In the urban air, sugars except levoglucosan gave a bimodal size distribution with a large peak in fine range (<2.1 μm) and a small peak in coarse range (≥2.1 μm) during winter, being opposite to those in spring. In contrast, these WSOCs at the mountain and marine sites dominated in the coarse range but diminished and even disappeared in the fine range. Geometric mean diameters (GMDs) of the measured WSOCs in the fine mode at the urban site were larger in winter than in spring. Levoglucosan and carboxylic acids except for azelaic and benzoic acids showed a larger GMD in the coarse mode at the marine site probably due to an increased hygroscopic growth.

The bark of the branches of holm oak (Quercus ilex L.) for a retrospective study of trace elements in the atmosphere.

PubMed

Drava, Giuliana; Brignole, Daniele; Giordani, Paolo; Minganti, Vincenzo

2017-04-01

Tree bark has proved to be a useful bioindicator for trace elements in the atmosphere, however it reflects an exposure occurring during an unidentified period of time, so it provides spatial information about the distribution of contaminants in a certain area, but it cannot be used to detect temporal changes or trends, which is an important achievement in environmental studies. In order to obtain information about a known period of time, the bark collected from the annual segments of tree branches can be used, allowing analyses going back 10-15 years with annual resolution. In the present study, the concentrations of As, Cd, Co, Cu, Fe, Mn, Ni, Pb, V and Zn were measured by atomic emission spectrometry in a series of samples covering the period from 2001 to 2013 in an urban environment. Downward time trends were significant for Cd, Pb and Zn. The only trace element showing an upward time trend was V. The concentrations of the remaining six trace elements were constant over time, showing that their presence in bark is not simply proportional to the duration of exposure. This approach, which is simple, reliable and widely applicable at a low cost, allows the "a posteriori" reconstruction of atmospheric trace element deposition when or where no monitoring programme is in progress and no other natural archives are available. Copyright © 2017 Elsevier Inc. All rights reserved.

Urban Modification of Convection and Rainfall in Complex Terrain

NASA Astrophysics Data System (ADS)

Freitag, B. M.; Nair, U. S.; Niyogi, D.

2018-03-01

Despite a globally growing proportion of cities located in regions of complex terrain, interactions between urbanization and complex terrain and their meteorological impacts are not well understood. We utilize numerical model simulations and satellite data products to investigate such impacts over San Miguel de Tucumán, Argentina. Numerical modeling experiments show urbanization results in 20-30% less precipitation downwind of the city and an eastward shift in precipitation upwind. Our experiments show that changes in surface energy, boundary layer dynamics, and thermodynamics induced by urbanization interact synergistically with the persistent forcing of atmospheric flow by complex terrain. With urbanization increasing in mountainous regions, land-atmosphere feedbacks can exaggerate meteorological forcings leading to weather impacts that require important considerations for sustainable development of urban regions within complex terrain.

Intra-Urban Variability in Elemental Carbon Deposition to Tree Canopies

NASA Astrophysics Data System (ADS)

Barrett, T. E.; Ponette-González, A.; Rindy, J. E.; Sheesley, R. J.

2017-12-01

Urban areas cover <1% of the earth's land surface, yet they represent globally significant sources of atmospheric elemental carbon (EC). A product of incomplete fossil fuel, biofuel, and biomass combustion, EC is a powerful climate-forcing agent and a significant component of fine particulate matter in urban atmospheres. Thus, understanding the factors that govern EC removal in urban areas could help mitigate climate change, while improving air quality for urban residents. EC particles can be removed from the atmosphere in precipitation (wet and fog deposition) or they can settle directly onto receptor surfaces (dry deposition). Only limited measurements indicate that EC deposition is higher in urban than in rural and remote regions. However, EC deposition likely exhibits considerable intra-urban variability, with tree canopies serving as potentially important sinks for EC on the cityscape. The goal of this research is to quantify spatial variability in total (wet + dry) EC deposition to urban tree canopies in the Dallas-Fort Worth Metroplex. Using a stratified non-random sampling design, 41 oak trees (22 post oak (Quercus stellata) and 19 live oak (Quercus virginiana)) were selected near (<100 m) and far from roads (>100 m) for measurements of throughfall (water that falls from the canopy to the forest floor). Additionally, 16 bulk rainfall samplers were deployed in grassy areas with no canopy cover. Results from one rain event indicate a volume weighted mean concentration of 83 µg EC L-1 in post oak throughfall, 36 µg EC L-1 in live oak throughfall, and 4 µg EC L-1 in bulk rainfall. Total EC deposition to oak tree canopies was 2.0 ± 2.1 (SD) mg m-2 for post oak and 0.7 ± 0.3 mg m-2 for live oak. Bulk rainfall deposition was 0.08 ± 0.1 mg m-2. Our preliminary findings show that trees are effective urban air filters, removing 9-25 times more EC from the atmosphere than rainwater alone. Resolving surface controls on atmospheric EC removal is key to developing and assessing near-term climate and air quality mitigation strategies.

The Effects of Urbanization on Atmospheric Nitrogen Deposition and Nitrate Removal Capacity of Urban Wetlands

NASA Astrophysics Data System (ADS)

Stander, E. K.; Ehrenfeld, J. G.

2006-12-01

Wetlands are increasingly being used as management tools to combat the widespread problem of excess nitrogen in surface waters of the United States. This is particularly true in urban or urbanizing watersheds. However, due to hypothesized higher rates of atmospheric nitrogen deposition and altered hydrology in the urban context, urban wetlands may actually be acting as sources of nitrate to receiving bodies of water. Fourteen palustrine, forested wetlands in northeastern New Jersey, the most urban part of the state, were sampled for hydrology and rates of nitrogen cycling processes. One autowell in each site recorded water table measurements four times daily. In situ rates of net nitrogen mineralization and nitrification were measured monthly during the same time period using the static core technique. Denitrification rates were measured monthly in laboratory incubations using the acetylene block technique. Additionally, in nine of the 14 sites, which represent a gradient of urban intensity from very urban to less urban, we measured inorganic nitrogen in throughfall and leachate on a weekly basis. Throughfall collectors and lysimeters to 50cm depth were installed in three locations in each of the nine sites. Throughfall and leachate samples were analyzed for 15N and 18O isotopes to distinguish between atmospheric versus nitrification sources of nitrate in soil leachate. Hydrographs demonstrated that many sites have water table depths below 30 cm (i.e., below the biologically active zone) for long periods of time. Many wetlands display uncharacteristically flashy hydrographs. Wetlands with dry or flashy hydrographs had higher rates of nitrification and lower rates of denitrification than wetlands with more normal hydrology. Rates of atmospheric N deposition were higher in wetlands located in municipalities with higher population densities. Population density, however, was not a good predictor of nitrification or denitrification rates. Results from the isotopic analysis are forthcoming.

Elevated Atmospheric Levels of Benzene and Benzene-Related Compounds from Unconventional Shale Extraction and Processing: Human Health Concern for Residential Communities.

PubMed

Rich, Alisa L; Orimoloye, Helen T

2016-01-01

The advancement of natural gas (NG) extraction across the United States (U.S.) raises concern for potential exposure to hazardous air pollutants (HAPs). Benzene, a HAP and a primary chemical of concern due to its classification as a known human carcinogen, is present in petroleum-rich geologic formations and is formed during the combustion of bypass NG. It is a component in solvents, paraffin breakers, and fuels used in NG extraction and processing (E&P). The objectives of this study are to confirm the presence of benzene and benzene-related compounds (benzene[s]) in residential areas, where unconventional shale E&P is occurring, and to determine if benzene[s] exists in elevated atmospheric concentrations when compared to national background levels. Ambient air sampling was conducted in six counties in the Dallas/Fort Worth Metroplex with passive samples collected in evacuated 6-L Summa canisters. Samples were analyzed by gas chromatography/mass spectrometry, with sampling performed at variable distances from the facility fence line. Elevated concentrations of benzene[s] in the atmosphere were identified when compared to U.S. Environmental Protection Agency's Urban Air Toxics Monitoring Program. The 24-hour benzene concentrations ranged from 0.6 parts per billion by volume (ppbv) to 592 ppbv, with 1-hour concentrations from 2.94 ppbv to 2,900.20 ppbv. Benzene is a known human carcinogen capable of multisystem health effects. Exposure to benzene is correlated with bone marrow and blood-forming organ damage and immune system depression. Sensitive populations (children, pregnant women, elderly, immunocompromised) and occupational workers are at increased risk for adverse health effects from elevated atmospheric levels of benzene[s] in residential areas with unconventional shale E&P.

The bark of the branches of holm oak (Quercus ilex L.) for a retrospective study of trace elements in the atmosphere

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

Drava, Giuliana, E-mail: drava@difar.unige.it; Bri

Tree bark has proved to be a useful bioindicator for trace elements in the atmosphere, however it reflects an exposure occurring during an unidentified period of time, so it provides spatial information about the distribution of contaminants in a certain area, but it cannot be used to detect temporal changes or trends, which is an important achievement in environmental studies. In order to obtain information about a known period of time, the bark collected from the annual segments of tree branches can be used, allowing analyses going back 10–15 years with annual resolution. In the present study, the concentrations ofmore » As, Cd, Co, Cu, Fe, Mn, Ni, Pb, V and Zn were measured by atomic emission spectrometry in a series of samples covering the period from 2001 to 2013 in an urban environment. Downward time trends were significant for Cd, Pb and Zn. The only trace element showing an upward time trend was V. The concentrations of the remaining six trace elements were constant over time, showing that their presence in bark is not simply proportional to the duration of exposure. This approach, which is simple, reliable and widely applicable at a low cost, allows the “a posteriori” reconstruction of atmospheric trace element deposition when or where no monitoring programme is in progress and no other natural archives are available. - Highlights: • Branch bark allows the historical reconstruction of atmospheric trace elements. • This approach is simple, reliable, widely applicable and “a posteriori”. • Downward time trends were found for Cd, Pb and Zn; upward trend for V.« less

Mutagenicity in Salmonella of a Simulated Urban-Smog Atmosphere Generated Using a Mobile Reaction Chamber

EPA Science Inventory

The EPA Mobile Reaction Chamber (MRC) is a 24-foot trailer containing a 14.3-m3 Teflon lined photochemical chamber used to generate simulated urban atmospheres. Photochemistry in the MRC is catalyzed by 120 fluorescent bulbs evenly mixed with black light bulbs and UV bulbs (300 &...

Global simulation of aromatic volatile organic compounds in the atmosphere

NASA Astrophysics Data System (ADS)

Cabrera Perez, David; Taraborrelli, Domenico; Pozzer, Andrea

2015-04-01

Among the large number of chemical compounds in the atmosphere, the organic group plays a key role in the tropospheric chemistry. Specifically the subgroup called aromatics is of great interest. Aromatics are the predominant trace gases in urban areas due to high emissions, primarily by vehicle exhausts and fuel evaporation. They are also present in areas where biofuel is used (i.e residential wood burning). Emissions of aromatic compounds are a substantial fraction of the total emissions of the volatile organic compounds (VOC). Impact of aromatics on human health is very important, as they do not only contribute to the ozone formation in the urban environment, but they are also highly toxic themselves, especially in the case of benzene which is able to trigger a range of illness under long exposure, and of nitro-phenols which cause detrimental for humans and vegetation even at very low concentrations. The aim of this work is to assess the atmospheric impacts of aromatic compounds on the global scale. The main goals are: lifetime and budget estimation, mixing ratios distribution, net effect on ozone production and OH loss for the most emitted aromatic compounds (benzene, toluene, xylenes, ethylbenzene, styrene and trimethylbenzenes). For this purpose, we use the numerical chemistry and climate simulation ECHAM/MESSy Atmospheric Chemistry (EMAC) model to build the global atmospheric budget for the most emitted and predominant aromatic compounds in the atmosphere. A set of emissions was prepared in order to include biomass burning, vegetation and anthropogenic sources of aromatics into the model. A chemical mechanism based on the Master Chemical Mechanism (MCM) was developed to describe the chemical oxidation in the gas phase of these aromatic compounds. MCM have been reduced in terms of number of chemical equation and species in order to make it affordable in a 3D model. Additionally other features have been added, for instance the production of HONO via ortho-nitrophenols photolysis. The model results are compared with observations from different surface and aircraft campaigns in order to estimate the accuracy of the model.

Street-level noise in an urban setting: assessment and contribution to personal exposure.

PubMed

McAlexander, Tara P; Gershon, Robyn R M; Neitzel, Richard L

2015-02-28

The urban soundscape, which represents the totality of noise in the urban setting, is formed from a wide range of sources. One of the most ubiquitous and least studied of these is street-level (i.e., sidewalk) noise. Mainly associated with vehicular traffic, street level noise is hard to ignore and hard to escape. It is also potentially dangerous, as excessive noise from any source is an important risk factor for adverse health effects. This study was conducted to better characterize the urban soundscape and the role of street level noise on overall personal noise exposure in an urban setting. Street-level noise measures were obtained at 99 street sites located throughout New York City (NYC), along with data on time, location, and sources of environmental noise. The relationship between street-level noise measures and potential predictors of noise was analyzed using linear and logistic regression models, and geospatial modeling was used to evaluate spatial trends in noise. Daily durations of street-level activities (time spent standing, sitting, walking and running on streets) were estimated via survey from a sample of NYC community members recruited at NYC street fairs. Street-level noise measurements were then combined with daily exposure durations for each member of the sample to estimate exposure to street noise, as well as exposure to other sources of noise. The mean street noise level was 73.4 dBA, with substantial spatial variation (range 55.8-95.0 dBA). Density of vehicular (road) traffic was significantly associated with excessive street level noise levels. Exposure duration data for street-level noise and other common sources of noise were collected from 1894 NYC community members. Based on individual street-level exposure estimates, and in consideration of all other sources of noise exposure in an urban population, we estimated that street noise exposure contributes approximately 4% to an average individual's annual noise dose. Street-level noise exposure is a potentially important source of overall noise exposure, and the reduction of environmental sources of excessive street- level noise should be a priority for public health and urban planning.

Formation of reactive nitrogen oxides from urban grime photochemistry

NASA Astrophysics Data System (ADS)

Baergen, Alyson M.; Donaldson, D. James

2016-05-01

Impervious surfaces are ubiquitous in urban environments and constitute a substrate onto which atmospheric constituents can deposit and undergo photochemical and oxidative processing, giving rise to "urban grime" films. HNO3 and N2O5 are important sinks for NOx in the lower atmosphere and may be deposited onto these films, forming nitrate through surface hydrolysis. Although such deposition has been considered as a net loss of NOx from the atmosphere, there is increasing evidence that surface-associated nitrate undergoes further reaction. Here, we examine the gas phase products of the photochemistry of real, field-collected urban grime using incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS). Gas phase nitrogen oxides are emitted upon illumination of grime samples and their production increases with ambient relative humidity (RH) up to 35 % after which the production becomes independent of RH. These results are discussed in the context of water uptake onto and evaporation from grime films.

Removal of Ozone by Urban and Peri-Urban Forests: Evidence from Laboratory, Field, and Modeling Approaches

Treesearch

Carlo Calfapietra; Arianna Morani; Gregorio Sgrigna; Sara Di Giovanni; Valerio Muzzini; Emanuele Pallozzi; Gabriele Guidolotti; David Nowak; Silvano Fares

2016-01-01

A crucial issue in urban environments is the interaction between urban trees and atmospheric pollution, particularly ozone (O3). Ozone represents one of the most harmful pollutants in urban and peri-urban environments, especially in warm climates. Besides the large interest in reducing anthropogenic and biogenic precursors of O3...

Building-Scale Atmospheric Modeling for Understanding and Anticipating Environmental Risks to Urban Populations

NASA Astrophysics Data System (ADS)

Warner, T. T.; Swerdlin, S. P.; Chen, F.; Hayden, M.

2009-05-01

The innovative use of Computational Fluid-Dynamics (CFD) models to define the building- and street-scale atmospheric environment in urban areas can benefit society in a number of ways. Design criteria used by architectural climatologists, who help plan the livable cities of the future, require information about air movement within street canyons for different seasons and weather regimes. Understanding indoor urban air- quality problems and their mitigation, especially for older buildings, requires data on air movement and associated dynamic pressures near buildings. Learning how heat waves and anthropogenic forcing in cities collectively affect the health of vulnerable residents is a problem in building thermodynamics, human behavior, and neighborhood-scale and street-canyon-scale atmospheric sciences. And, predicting the movement of plumes of hazardous material released in urban industrial or transportation accidents requires detailed information about vertical and horizontal air motions in the street canyons. These challenges are closer to being addressed because of advances in CFD modeling, the coupling of CFD models with models of indoor air motion and air quality, and the coupling of CFD models with mesoscale weather-prediction models. This paper will review some of the new knowledge and technologies that are being developed to meet these atmospheric-environment needs of our growing urban populations.

Urbanity as a determinant of exposure to grass pollen in Helsinki Metropolitan area, Finland.

PubMed

Hugg, Timo T; Hjort, Jan; Antikainen, Harri; Rusanen, Jarmo; Tuokila, Mirkka; Korkonen, Sanna; Weckström, Jan; Jaakkola, Maritta S; Jaakkola, Jouni J K

2017-01-01

Little is known about the levels of exposure to grass pollen in urban environments. We assessed the spatio-temporal variation of grass pollen concentrations and the role of urbanity as a determinant of grass pollen exposure in the Helsinki Metropolitan area. We monitored grass pollen concentrations in 2013 at 16 sites during the peak pollen season by using rotorod-type samplers at the breathing height. The sites were in the cities of Helsinki and Espoo, Finland, and formed city-specific lines that represented urban-rural gradient. The monitoring sites were both visually and based on land use data ranked as high to low (graded 1 to 8) pollen area. The lowest grass pollen concentrations were observed in the most urban sites compared to the least urban sites (mean 3.6 vs. 6.8 grains/m3 in Helsinki; P<0.0001, and 5.2 vs. 87.5 grains/m3 in Espoo; P<0.0001). Significant differences were observed between concentrations measured in morning periods compared to afternoon periods (4.9 vs. 5.4 in Helsinki, P = 0.0186, and 21.8 vs. 67.1 in Espoo, P = 0.0004). The mean pollen concentration increased with decreasing urbanity both in Helsinki (0.59 grains/m3 per urbanity rank, 95% CI 0.25-0.93) and Espoo (8.42, 6.23-10.61). Pollen concentrations were highest in the afternoons and they were related to the ambient temperature. Urbanity was a strong and significant determinant of pollen exposure in two Finnish cities. Pollen exposure can periodically reach such high levels even in the most urban environments that can cause allergic reactions among individuals with allergies.

Urbanity as a determinant of exposure to grass pollen in Helsinki Metropolitan area, Finland

PubMed Central

Hugg, Timo T.; Hjort, Jan; Antikainen, Harri; Rusanen, Jarmo; Tuokila, Mirkka; Korkonen, Sanna; Weckström, Jan; Jaakkola, Maritta S.

2017-01-01

Little is known about the levels of exposure to grass pollen in urban environments. We assessed the spatio-temporal variation of grass pollen concentrations and the role of urbanity as a determinant of grass pollen exposure in the Helsinki Metropolitan area. We monitored grass pollen concentrations in 2013 at 16 sites during the peak pollen season by using rotorod-type samplers at the breathing height. The sites were in the cities of Helsinki and Espoo, Finland, and formed city-specific lines that represented urban-rural gradient. The monitoring sites were both visually and based on land use data ranked as high to low (graded 1 to 8) pollen area. The lowest grass pollen concentrations were observed in the most urban sites compared to the least urban sites (mean 3.6 vs. 6.8 grains/m3 in Helsinki; P<0.0001, and 5.2 vs. 87.5 grains/m3 in Espoo; P<0.0001). Significant differences were observed between concentrations measured in morning periods compared to afternoon periods (4.9 vs. 5.4 in Helsinki, P = 0.0186, and 21.8 vs. 67.1 in Espoo, P = 0.0004). The mean pollen concentration increased with decreasing urbanity both in Helsinki (0.59 grains/m3 per urbanity rank, 95% CI 0.25–0.93) and Espoo (8.42, 6.23–10.61). Pollen concentrations were highest in the afternoons and they were related to the ambient temperature. Urbanity was a strong and significant determinant of pollen exposure in two Finnish cities. Pollen exposure can periodically reach such high levels even in the most urban environments that can cause allergic reactions among individuals with allergies. PMID:29023565

Extracting Urban Morphology for Atmospheric Modeling from Multispectral and SAR Satellite Imagery

NASA Astrophysics Data System (ADS)

Wittke, S.; Karila, K.; Puttonen, E.; Hellsten, A.; Auvinen, M.; Karjalainen, M.

2017-05-01

This paper presents an approach designed to derive an urban morphology map from satellite data while aiming to minimize the cost of data and user interference. The approach will help to provide updates to the current morphological databases around the world. The proposed urban morphology maps consist of two layers: 1) Digital Elevation Model (DEM) and 2) land cover map. Sentinel-2 data was used to create a land cover map, which was realized through image classification using optical range indices calculated from image data. For the purpose of atmospheric modeling, the most important classes are water and vegetation areas. The rest of the area includes bare soil and built-up areas among others, and they were merged into one class in the end. The classification result was validated with ground truth data collected both from field measurements and aerial imagery. The overall classification accuracy for the three classes is 91 %. TanDEM-X data was processed into two DEMs with different grid sizes using interferometric SAR processing. The resulting DEM has a RMSE of 3.2 meters compared to a high resolution DEM, which was estimated through 20 control points in flat areas. Comparing the derived DEM with the ground truth DEM from airborne LIDAR data, it can be seen that the street canyons, that are of high importance for urban atmospheric modeling are not detectable in the TanDEM-X DEM. However, the derived DEM is suitable for a class of urban atmospheric models. Based on the numerical modeling needs for regional atmospheric pollutant dispersion studies, the generated files enable the extraction of relevant parametrizations, such as Urban Canopy Parameters (UCP).

Spatio-Temporal Analysis of MODIS Retrieved Precipitable Water Vapor over Urban and Rural Areas in the Philippines

NASA Astrophysics Data System (ADS)

Galvez, M. C. D.; Castilla, R. M.; Catenza, J. L. U.; Soronio, H.; Vallar, E. A.

2016-12-01

Precipitable water vapor (PWV) is a component of the atmosphere that significantly influences many atmospheric processes. It plays a dominant role in the high-energy thermodynamics of the atmosphere, notably, the genesis of storm systems. Remote sensing of the atmosphere using MODerate resolution Imaging Spectroradiometer (MODIS) offers a relatively inexpensive method to estimate atmospheric water vapour in the form of columnar measurements from its 936 nm near-infrared band. Daily Level 3 data with 1 degree grid spatial resolution from MODIS was used in order to determine the temporal and spatial variability of precipitable water between urban and rural areas in the Philippines. The PWV values were rasterized and spatially interpolated to be stored in a 1 kilometer grid resolution using the nearest-neighbor algorithm. General Linear Models were established to determine the main and interaction effects on PWV values of several categorical factors e.g. time, administrative region, and geographic classification. Comparison between the urban and rural areas in the Philippines showed that there is a significant difference between the values between these demographic dimensions. The mean PWV in the urban areas was found to be 0.0473 cm greater than the mean PWV of the rural areas. Lower levels of precipitable water vapour in rural places can be attributed to the low humidity as a result of a deficit of precipitation; while higher levels in urban areas can be accounted for by vehicle exhaust, industrial emissions, and irrigation of parks and gardens. In general, PWV varies depending on the season when solar insolation affects surface temperature, thus influencing the rate of evaporation. Using the regression line algorithm, the PWV values for rural areas have increased to 0.904 cm and 0.434 cm for urban areas from the year 2005 to 2015.

Inhibition of atmospheric corrosion of mild steel by sodium benzoate treatment

NASA Astrophysics Data System (ADS)

Kahraman, Ramazan

2002-02-01

The objective of this study was to evaluate the effectiveness of sodium benzoate as an inhibitor to slow down or prevent atmospheric corrosion/discoloration of the local mild steel during storage in the Arabian Gulf region. Test specimens were prepared from locally produced reinforcing steel products. The inhibitor solution was applied on steel specimens at a concentration of 100 mM for 1 day at room temperature. Wooden exposure racks were used to hold as-received and inhibitor-treated specimens during atmospheric exposure for different periods. Corrosion was evaluated through weight loss determination and electrochemical technique. As expected, the Arabian Gulf atmosphere was corrosive on the as-received local mild steel. On the other hand, treatment of steel with sodium benzoate lowered its corrosion rate during initial days of its exposure to atmosphere. However, atmospheric corrosion inhibition performance of sodium benzoate deteriorated with exposure time after 30 or more days of atmospheric exposure, and the corrosion rates of sodium benzoate-treated specimens reached that of the unprotected specimens at the end of 90 days of atmospheric exposure.

Gray Wave of the Great Transformation: A Satellite View of Urbanization, Climate, and Food Security

NASA Technical Reports Server (NTRS)

Imhoff, Marc L.

2007-01-01

Land cover change driven by human activity is profoundly affecting Earth's natural systems with impacts ranging from a loss of biological productivity to changes in atmospheric chemistry and regional and global climate. This change has been so pervasive and progressed so rapidly, compared to natural processes, scientists refer to it as 'the great transformation'. Urbanization or the 'gray wave' of this transformation is being increasingly recognized as an important process in global climate change. A hallmark of our success as a species, large urban conglomerates do in fact alter their environments so profoundly that the local climate, atmospheric composition, and the basic ecology of the landscape are affected in ways that have consequences to human health and economic well-being. Fortunately we have incredible new tools to observe and understand these processes in ways that can be used to plan and develop enjoyable and sustainable urban places. A suite of Earth observing satellites is making it possible to study the interactions between urbanization, biological processes, and the atmosphere including weather and climate. Using these Earth Observatories we are learning how urban heat islands form and potentially ameliorate them, how urbanization can affect rainfall, pollution, surface water recharge at the local level, and climate and food security globally.

Coupling of WRF and Building-resolved CFD Simulations for Greenhouse Gas Transport and Dispersion

NASA Astrophysics Data System (ADS)

Prasad, K.; Hu, H.; McDermott, R.; Lopez-Coto, I.; Davis, K. J.; Whetstone, J. R.; Lauvaux, T.

2014-12-01

The Indianapolis Flux Experiment (INFLUX) aims to use a top-down inversion methodology to quantify sources of Greenhouse Gas (GHG) emissions over an urban domain with high spatial and temporal resolution. Atmospheric transport of tracer gases from an emission source to a tower mounted receptor are usually conducted using the Weather Research and Forecasting (WRF) model. WRF is used extensively in the atmospheric community to simulate mesoscale atmospheric transport. For such simulations, WRF employs a parameterized turbulence model and does not resolve the fine scale dynamics that are generated by the flow around buildings and communities that are part of a large city. Since the model domain includes the city of Indianapolis, much of the flow of interest is over an urban topography. The NIST Fire Dynamics Simulator (FDS) is a computational fluid dynamics model to perform large eddy simulations of flow around buildings, but it has not been nested within a larger-scale atmospheric transport model such as WRF. FDS has the potential to evaluate the impact of complex urban topography on near-field dispersion and mixing that cannot be simulated with a mesoscale atmospheric model, and which may be important to determining urban GHG emissions using atmospheric measurements. A methodology has been developed to run FDS as a sub-grid scale model within a WRF simulation. The coupling is based on nudging the FDS flow field towards the one computed by WRF, and is currently limited to one way coupling performed in an off-line mode. Using the coupled WRF / FDS model, NIST will investigate the effects of the urban canopy at horizontal resolutions of 2-10 m. The coupled WRF-FDS simulations will be used to calculate the dispersion of tracer gases in an urban domain and to evaluate the upwind areas that contribute to tower observations, referred to in the inversion community as influence functions. Predicted mixing ratios will be compared with tower measurements and WRF simulations, and FDS influence functions will be compared with those generated from WRF and the Lagrangian Particle Dispersion Model. Results of this study will provide guidance regarding the importance of explicit simulations of urban atmospheric turbulence in obtaining accurate estimates of greenhouse gas emissions.

Repeated exposures to roadside particulate matter extracts suppresses pulmonary defense mechanisms, resulting in lipid and protein oxidative damage.

PubMed

Pardo, Michal; Porat, Ziv; Rudich, Assaf; Schauer, James J; Rudich, Yinon

2016-03-01

Exposure to particulate matter (PM) pollution in cities and urban canyons can be harmful to the exposed population. However, the underlying mechanisms that lead to health effects are not yet elucidated. It is postulated that exposure to repeated, small, environmentally relevant concentrations can affect lung homeostasis. This study examines the impact of repeated exposures to urban PM on mouse lungs with focus on inflammatory and oxidative stress parameters. Aqueous extracts from collected urban PM were administered to mice by 5 repeated intra-tracheal instillations (IT). Multiple exposures, led to an increase in cytokine levels in both bronchoalveolar lavage fluid and in the blood serum, indicating a systemic reaction. Lung mRNA levels of antioxidant/phase II detoxifying enzymes decreased by exposure to the PM extract, but not when metals were removed by chelation. Finally, disruption of lung tissue oxidant-inflammatory/defense balance was evidenced by increased levels of lipid and protein oxidation. Unlike response to a single IT exposure to the same dose and source of extract, multiple exposures result in lung oxidative damage and a systemic inflammatory reaction. These could be attributed to compromised capacity to activate the protective Nrf2 tissue defense system. It is suggested that water-soluble metals present in urban PM, potentially from break and tire wear, may constitute major drivers of the pulmonary and systemic responses to multiple exposure to urban PM. Copyright © 2015 Elsevier Ltd. All rights reserved.

Foliar or root exposures to smelter particles: consequences for lead compartmentalization and speciation in plant leaves.

PubMed

Schreck, Eva; Dappe, Vincent; Sarret, Géraldine; Sobanska, Sophie; Nowak, Dorota; Nowak, Jakub; Stefaniak, Elżbieta Anna; Magnin, Valérie; Ranieri, Vincent; Dumat, Camille

2014-04-01

In urban areas with high fallout of airborne particles, metal uptake by plants mainly occurs by foliar pathways and can strongly impact crop quality. However, there is a lack of knowledge on metal localization and speciation in plants after pollution exposure, especially in the case of foliar uptake. In this study, two contrasting crops, lettuce (Lactuca sativa L.) and rye-grass (Lolium perenne L.), were exposed to Pb-rich particles emitted by a Pb-recycling factory via either atmospheric or soil application. Pb accumulation in plant leaves was observed for both ways of exposure. The mechanisms involved in Pb uptake were investigated using a combination of microscopic and spectroscopic techniques (electron microscopy, laser ablation, Raman microspectroscopy, and X-ray absorption spectroscopy). The results show that Pb localization and speciation are strongly influenced by the type of exposure (root or shoot pathway) and the plant species. Foliar exposure is the main pathway of uptake, involving the highest concentrations in plant tissues. Under atmospheric fallouts, Pb-rich particles were strongly adsorbed on the leaf surface of both plant species. In lettuce, stomata contained Pb-rich particles in their apertures, with some deformations of guard cells. In addition to PbO and PbSO4, chemical forms that were also observed in pristine particles, new species were identified: organic compounds (minimum 20%) and hexagonal platy crystals of PbCO3. In rye-grass, the changes in Pb speciation were even more egregious: Pb-cell wall and Pb-organic acid complexes were the major species observed. For root exposure, identified here as a minor pathway of Pb transfer compared to foliar uptake, another secondary species, pyromorphite, was identified in rye-grass leaves. Finally, combining bulk and spatially resolved spectroscopic techniques permitted both the overall speciation and the minor but possibly highly reactive lead species to be determined in order to better assess the health risks involved. Copyright © 2013 Elsevier B.V. All rights reserved.

Hypothesis: Urbanization and exposure to urban heat islands contribute to increasing prevalence of kidney stones.

PubMed

Goldfarb, David S; Hirsch, Jacqueline

2015-12-01

The prevalence of kidney stones is increasing worldwide. Various etiologies may in part explain this observation including increased prevalence of diabetes, obesity and the metabolic syndrome, increased dietary protein and salt content, and decreased dietary dairy products. We hypothesize an additional and novel potential contributor to increasing kidney stone prevalence: migration to urban settings, or urbanization, and resultant exposure of the population to the higher temperatures of urban heat islands (UHIs). Both urbanization and exposure to UHIs are worldwide, continuous trends. Because the difference in temperature between rural and urban settings is greater than the increase in temperature caused by global warming, the potential effect of urbanization on stone prevalence may be of greater magnitude. However, demonstration of a convincing link between urbanization and kidney stones is confounded by many variables simultaneously affected by migration to cities, such as changes in occupation, income, and diet. No data have yet been published supporting this proposed association. We explore the plausibility and limitations of this possible etiology of increasing kidney stone prevalence. Published by Elsevier Ltd.

Accidental release of chlorine in Chicago: Coupling of an exposure model with a Computational Fluid Dynamics model

NASA Astrophysics Data System (ADS)

Sanchez, E. Y.; Colman Lerner, J. E.; Porta, A.; Jacovkis, P. M.

2013-01-01

The adverse health effects of the release of hazardous substances into the atmosphere continue being a matter of concern, especially in densely populated urban regions. Emergency responders need to have estimates of these adverse health effects in the local population to aid planning, emergency response, and recovery efforts. For this purpose, models that predict the transport and dispersion of hazardous materials are as necessary as those that estimate the adverse health effects in the population. In this paper, we present the results obtained by coupling a Computational Fluid Dynamics model, FLACS (FLame ACceleration Simulator), with an exposure model, DDC (Damage Differential Coupling). This coupled model system is applied to a scenario of hypothetical release of chlorine with obstacles, such as buildings, and the results show how it is capable of predicting the atmospheric dispersion of hazardous chemicals, and the adverse health effects in the exposed population, to support decision makers both in charge of emergency planning and in charge of real-time response. The results obtained show how knowing the influence of obstacles in the trajectory of the toxic cloud and in the diffusion of the pollutants transported, and obtaining dynamic information of the potentially affected population and of associated symptoms, contribute to improve the planning of the protection and response measures.

Socioeconomic and urban-rural differentials in exposure to air pollution and mortality burden in England.

PubMed

Milojevic, Ai; Niedzwiedz, Claire L; Pearce, Jamie; Milner, James; MacKenzie, Ian A; Doherty, Ruth M; Wilkinson, Paul

2017-10-06

Socioeconomically disadvantaged populations often have higher exposures to particulate air pollution, which can be expected to contribute to differentials in life expectancy. We examined socioeconomic differentials in exposure and air pollution-related mortality relating to larger scale (5 km resolution) variations in background concentrations of selected pollutants across England. Ozone and particulate matter (sub-divided into PM 10 , PM 2.5 , PM 2.5-10 , primary, nitrate and sulphate PM 2.5 ) were simulated at 5 km horizontal resolution using an atmospheric chemistry transport model (EMEP4UK). Annual mean concentrations of these pollutants were assigned to all 1,202,578 residential postcodes in England, which were classified by urban-rural status and socioeconomic deprivation based on the income and employment domains of the 2010 English Index of Multiple Deprivation for the Lower-level Super Output Area of residence. We used life table methods to estimate PM 2.5 -attributable life years (LYs) lost in both relative and absolute terms. Concentrations of the most particulate fractions, but not of nitrate PM 2.5 or ozone, were modestly higher in areas of greater socioeconomic deprivation. Relationships between pollution level and socioeconomic deprivation were non-linear and varied by urban-rural status. The pattern of PM 2.5 concentrations made only a small contribution to the steep socioeconomic gradient in LYs lost due to PM 2.5 per 10 3 population, which primarily was driven by the steep socioeconomic gradient in underlying mortality rates. In rural areas, the absolute burden of air pollution-related LYs lost was lowest in the most deprived deciles. Air pollution shows modest socioeconomic patterning at 5 km resolution in England, but absolute attributable mortality burdens are strongly related to area-level deprivation because of underlying mortality rates. Measures that cause a general reduction in background concentrations of air pollution may modestly help narrow socioeconomic differences in health.

Urban-rural differences in breast cancer incidence by hormone receptor status across 6 years in Egypt

PubMed Central

Dey, Subhojit; Soliman, Amr S.; Hablas, Ahmad; Seifeldin, Ibrahim A.; Ismail, Kadry; Ramadan, Mohamed; El-Hamzawy, Hesham; Wilson, Mark L.; Banerjee, Mousumi; Boffetta, Paolo; Harford, Joe; Merajver, Sofia D.

2009-01-01

Breast cancer incidence is higher in developed countries with higher rates of estrogen receptor positive (ER+) tumors. ER+ tumors are caused by estrogenic exposures although known exposures explain approximately 50% of breast cancer risk. Unknown risk factors causing high breast cancer incidence exist that are estrogenic and development-related. Xenoestrogens are such risk factors but are difficult to study since developed countries lack unexposed populations. Developing countries have urban-rural populations with differential exposure to xenoestrogens. This study assessed urban-rural breast cancer incidence classified by hormone receptor status using data from Gharbiah population-based cancer registry in Egypt from 2001 to 2006. Urban ER+ incidence rate (per 100,000 women) was 2-4 times (IRR = 3.36, 95% CI = 4.84, 2.34) higher than rural incidence rate. ER− incidence rate was 2-3 times (IRR = 1.86, 95% CI = 2.38, 1.45) higher in urban areas than in rural areas. Our findings indicate that urban women may probably have a higher exposure to xenoestrogens. PMID:19548084

Heavy - metal biomonitoring by using moss bags in Florence urban area, Italy

NASA Astrophysics Data System (ADS)

Pellizzaro, Grazia; Canu, Annalisa; Arca, Angelo; Duce, Pierpaolo

2013-04-01

In the last century, pollution has become one of the most important risks for environment. In particular, heavy metal presence in air, water and soil induces toxic effects on ecosystems and human health. Monitoring airborne trace element over large areas is a task not easy to reach since the concentrations of pollutants are variable in space and time. Data from automatic devices are site-specific and very limited in number to describe spatial-temporal trends of pollutants. In addition, especially in Italy, trace elements concentrations are not often recorded by most of the automated monitoring stations. In the last decades, development of alternative and complementary methods as bio-monitoring techniques, allowed to map deposition patterns not only near single pollution sources, but also over relatively large areas at municipal or even regional scale. Bio-monitoring includes a wide array of methodologies finalised to study relationships between pollution and living organisms. Mosses and lichens have been widely used as bio-accumulators for assessing the atmospheric deposition of heavy metals in natural ecosystems and urban areas. In this study bio-monitoring of airborne trace metals was made using moss bags technique. The moss Hypnum cupressiforme was used as bio-indicator for estimating atmospheric traces metal deposition in the urban area of Florence. Moss carpets were collected in a forested area of central Sardinia (municipality of Bolotana - Nuoro), which is characterised by absence of air pollution. Moss bags were located in the urban area of Florence close to three monitoring air quality stations managed by ARPAT (Agenzia Regionale Protezione Ambiente Toscana). Two stations were located in high-traffic roads whereas the other one was located in a road with less traffic density. In each site moss bags were exposed during three campaigns of measurement conducted during the periods March-April, May-July, and August-October 2010. Two moss bags, used as control, were not exposed. After exposure periods, moss bags were removed and moss samples were analyzed for As, Cr, Cu, Fe, Ni, Pb, V, and Zn by Inductively Coupled Plasma Atomic Emission Spectrometry. Results show differences between mean concentration of trace metals in moss bags after-exposure and the respective blanks in the three sample sites of Florence during the three campaigns of measurement. The highest concentrations for almost all elements were recorded at high-traffic road sites. Whereas lower values were detected in site located in a road with less traffic density In conclusion, Hypnum cupressiforme, for his high ability to accumulate trace metals, can be efficiently used as bio-indicator to estimate the trend of air pollution in a urban area during a period time.

Occupational Exposure to Vapor-Gas, Dust, and Fumes in a Cohort of Rural Adults in Iowa Compared with a Cohort of Urban Adults.

PubMed

Doney, Brent C; Henneberger, Paul K; Humann, Michael J; Liang, Xiaoming; Kelly, Kevin M; Cox-Ganser, Jean M

2017-11-03

Many rural residents work in the field of agriculture; however, employment in nonagricultural jobs also is common. Because previous studies in rural communities often have focused on agricultural workers, much less is known about the occupational exposures in other types of jobs in rural settings. Characterizing airborne occupational exposures that can contribute to respiratory diseases is important so that differences between rural and urban working populations can be assessed. 1994-2011. This investigation used data from the baseline questionnaire completed by adult rural residents participating in the Keokuk County Rural Health Study (KCRHS). The distribution of jobs and occupational exposures to vapor-gas, dust, and fumes (VGDF) among all participants was analyzed and stratified by farming status (current, former, and never) then compared with a cohort of urban workers from the Multi-Ethnic Study of Atherosclerosis (MESA). Occupational exposure in the last job was assessed with a job-exposure matrix (JEM) developed for chronic obstructive pulmonary disease (COPD). The COPD JEM assesses VGDF exposure at levels of none or low, medium, and high. The 1,699 KCRHS (rural) participants were more likely to have medium or high occupational VGDF exposure (43.2%) at their last job than their urban MESA counterparts (15.0% of 3,667 participants). One fifth (20.8%) of the rural participants currently farmed, 43.1% were former farmers, and approximately one third (36.1%) had never farmed. These three farming groups differed in VGDF exposure at the last job, with the prevalence of medium or high exposure at 80.2% for current farmers, 38.7% for former farmers, and 27.4% for never farmers, and all three percentages were higher than the 15.0% medium or high level of VGDF exposure for urban workers. Rural workers, including those who had never farmed, were more likely to experience occupational VGDF exposure than urban workers. The occupational exposures of rural adults assessed using the COPD JEM will be used to investigate their potential association with obstructive respiratory health problems (e.g., airflow limitation and chronic bronchitis). This assessment might highlight occupations in need of preventive interventions.

Turbulence and pollutant transport in urban street canyons under stable stratification: a large-eddy simulation

NASA Astrophysics Data System (ADS)

Li, X.

2014-12-01

Thermal stratification of the atmospheric surface layer has strong impact on the land-atmosphere exchange of turbulent, heat, and pollutant fluxes. Few studies have been carried out for the interaction of the weakly to moderately stable stratified atmosphere and the urban canopy. This study performs a large-eddy simulation of a modeled street canyon within a weakly to moderately stable atmosphere boundary layer. To better resolve the smaller eddy size resulted from the stable stratification, a higher spatial and temporal resolution is used. The detailed flow structure and turbulence inside the street canyon are analyzed. The relationship of pollutant dispersion and Richardson number of the atmosphere is investigated. Differences between these characteristics and those under neutral and unstable atmosphere boundary layer are emphasized.

Modeling exposures to organophosphates and pyrethroids for children living in an urban low-income environment

EPA Science Inventory

Pesticide exposure in urban low-income residential environments may be elevated as a result of persistent application due to severe pest infestation. Children living in this environment may be a sensitive subpopulation for these non-dietary exposures, due to their physiological a...

Assessment of Fecal Exposure Pathways in Low-Income Urban Neighborhoods in Accra, Ghana: Rationale, Design, Methods, and Key Findings of the SaniPath Study

PubMed Central

Robb, Katharine; Null, Clair; Teunis, Peter; Yakubu, Habib; Armah, George; Moe, Christine L.

2017-01-01

Abstract. Rapid urbanization has contributed to an urban sanitation crisis in low-income countries. Residents in low-income, urban neighborhoods often have poor sanitation infrastructure and services and may experience frequent exposure to fecal contamination through a range of pathways. There are little data to prioritize strategies to decrease exposure to fecal contamination in these complex and highly contaminated environments, and public health priorities are rarely considered when planning urban sanitation investments. The SaniPath Study addresses this need by characterizing pathways of exposure to fecal contamination. Over a 16 month period, an in-depth, interdisciplinary exposure assessment was conducted in both public and private domains of four neighborhoods in Accra, Ghana. Microbiological analyses of environmental samples and behavioral data collection techniques were used to quantify fecal contamination in the environment and characterize the behaviors of adults and children associated with exposure to fecal contamination. Environmental samples (n = 1,855) were collected and analyzed for fecal indicators and enteric pathogens. A household survey with 800 respondents and over 500 hours of structured observation of young children were conducted. Approximately 25% of environmental samples were collected in conjunction with structured observations (n = 441 samples). The results of the study highlight widespread and often high levels of fecal contamination in both public and private domains and the food supply. The dominant fecal exposure pathway for young children in the household was through consumption of uncooked produce. The SaniPath Study provides critical information on exposure to fecal contamination in low-income, urban environments and ultimately can inform investments and policies to reduce these public health risks. PMID:28722599

A Comparison of Particulate Matter from Biomass-Burning Rural and Non-Biomass-Burning Urban Households in Northeastern China

PubMed Central

Jiang, Ruoting; Bell, Michelle L.

2008-01-01

Background Biomass fuel is the primary source of domestic fuel in much of rural China. Previous studies have not characterized particle exposure through time–activity diaries or personal monitoring in mainland China. Objectives In this study we characterized indoor and personal particle exposure in six households in northeastern China (three urban, three rural) and explored differences by location, cooking status, activity, and fuel type. Rural homes used biomass. Urban homes used a combination of electricity and natural gas. Methods Stationary monitors measured hourly indoor particulate matter (PM) with an aerodynamic diameter ≤ 10 μm (PM10) for rural and urban kitchens, urban sitting rooms, and outdoors. Personal monitors for PM with an aerodynamic diameter ≤ 2.5 μm (PM2.5) were employed for 10 participants. Time–activity patterns in 30-min intervals were recorded by researchers for each participant. Results Stationary monitoring results indicate that rural kitchen PM10 levels are three times higher than those in urban kitchens during cooking. PM10 was 6.1 times higher during cooking periods than during noncooking periods for rural kitchens. Personal PM2.5 levels for rural cooks were 2.8–3.6 times higher than for all other participant categories. The highest PM2.5 exposures occurred during cooking periods for urban and rural cooks. However, rural cooks had 5.4 times higher PM2.5 levels during cooking than did urban cooks. Rural cooks spent 2.5 times more hours per day cooking than did their urban counterparts. Conclusions These findings indicate that biomass burning for cooking contributes substantially to indoor particulate levels and that this exposure is particularly elevated for cooks. Second-by-second personal PM2.5 exposures revealed differences in exposures by population group and strong temporal heterogeneity that would be obscured by aggregate metrics. PMID:18629313

A comparison of particulate matter from biomass-burning rural and non-biomass-burning urban households in northeastern China.

PubMed

Jiang, Ruoting; Bell, Michelle L

2008-07-01

Biomass fuel is the primary source of domestic fuel in much of rural China. Previous studies have not characterized particle exposure through time-activity diaries or personal monitoring in mainland China. In this study we characterized indoor and personal particle exposure in six households in northeastern China (three urban, three rural) and explored differences by location, cooking status, activity, and fuel type. Rural homes used biomass. Urban homes used a combination of electricity and natural gas. Stationary monitors measured hourly indoor particulate matter (PM) with an aerodynamic diameter < or = 10 microm (PM10) for rural and urban kitchens, urban sitting rooms, and outdoors. Personal monitors for PM with an aerodynamic diameter < or = 2.5 microm (PM2.5) were employed for 10 participants. Time-activity patterns in 30-min intervals were recorded by researchers for each participant. Stationary monitoring results indicate that rural kitchen PM10 levels are three times higher than those in urban kitchens during cooking. PM10 was 6.1 times higher during cooking periods than during noncooking periods for rural kitchens. Personal PM2.5 levels for rural cooks were 2.8-3.6 times higher than for all other participant categories. The highest PM2.5 exposures occurred during cooking periods for urban and rural cooks. However, rural cooks had 5.4 times higher PM2.5 levels during cooking than did urban cooks. Rural cooks spent 2.5 times more hours per day cooking than did their urban counterparts. These findings indicate that biomass burning for cooking contributes substantially to indoor particulate levels and that this exposure is particularly elevated for cooks. Second-by-second personal PM2.5 exposures revealed differences in exposures by population group and strong temporal heterogeneity that would be obscured by aggregate metrics.

Early life urban exposure as a risk factor for developing obesity and impaired fasting glucose in later adulthood: results from two cohorts in Thailand.

PubMed

Angkurawaranon, Chaisiri; Wisetborisut, Anawat; Rerkasem, Kittipan; Seubsman, Sam-Ang; Sleigh, Adrian; Doyle, Pat; Nitsch, Dorothea

2015-09-16

Obesity and obesity related conditions, driven by processes such as urbanization and globalization, are contributing to pronounced cardiovascular morbidity and mortality in developing countries. There is limited evidence on the influence of living in an urban environment in early life on obesity and obesity related conditions later in life in developing countries such as Thailand. We used data from two cohort studies conducted in Thailand, the Thai Cohort Study (TCS) and the Chiang Mai University (CMU) Health Worker Study, to investigate the association between early life urban (vs rural) exposure and the later development of obesity. We additionally explored the association between early life urban exposure and impaired fasting glucose in adulthood using data from the CMU Health Worker Study. Among 48,490 adults from the TCS, 9.1 % developed obesity within 4 years of follow-up. Among 1,804 initially non-obese adults from CMU Health worker study, 13.6 % developed obesity within 5 years of follow-up. Early life urban exposure was associated with increased risk of developing obesity in adulthood in both cohorts. Adjusting for age and sex, those who spent their early lives in urban areas were 1.21 times more likely to develop obesity in the TCS (OR 1.21, 95 % CI 1.12 to 1.31) and 1.65 times more likely in the CMU Health Worker study (OR 1.65, 95 % CI 1.23 to 2.20). These associations remained significant despite adjustment for later life urban exposure and current household income. No evidence for an association was found for impaired fasting glucose. Early life urban exposure was associated with increased risk of developing obesity in adulthood. These findings support public health intervention programs to prevent obesity starting from early ages.

Characterization of Potential Aerosol Mass using an Oxidation Chamber coupled to an Aerodyne HR-ToF-AMS during DAURE, SHARP, and FLAME-3

NASA Astrophysics Data System (ADS)

Ortega, A. M.; Brune, W. H.; Cubison, M.; Lefer, B. L.; Schallharter, S.; Metzger, A.; Mueller, M.; Hansel, A.; Jimenez, J. L.

2009-12-01

The Potential Aerosol Mass (PAM) oxidation chamber (Kang et al., ACP 2007) used in front of an aerosol instrument provides an indication of the secondary inorganic and organic aerosol formation potential in an airmass. The chamber, a flow tube with small residence time, rapidly oxidizes ambient air through exposure to high concentrations of ozone (O3) and hydroxy (OH) and hydroperoxy (HO2) radicals. Here we use a recently-modified PAM chamber in conjunction with an Aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS; DeCarlo et al., Anal. Chem. 2006) during two ambient studies and one source study: the Determination of the Sources of the Atmospheric Aerosol in Urban and Rural Environments in Spain (DAURE) in February 2009, the Study of Houston Atmospheric Radical Precursors (SHARP) in April 2009, and the Fire Lab at Missoula Experiment phase 3 (FLAME-3) in Sep. 2009. The AMS samples alternatively between ambient air and chamber-processed air every 2.5 min., and a cycling of the UV light intensity (OH exposure) is also used with a maximum equivalent exposure of about 7 days. Large variations in the organic PAM were observed in the different studies. In particular very large PAM values were observed in several evenings in Houston when the site was impacted by emissions from petrochemical facilities. Optimum OH exposure for maximum PAM was observed at intermediate OH levels. For all experiments we compare the amount of SOA formed in the PAM chamber to the yield predicted by the measured precursors (from PTRMS instruments).

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

NASA Technical Reports Server (NTRS)

Spruce, Joseph P.

2007-01-01

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

The influence from synoptic weather on the variation of air pollution and pollen exposure

NASA Astrophysics Data System (ADS)

Grundström, Maria; Dahl, Åslög; Chen, Deliang; Pleijel, Håkan

2014-05-01

Exposure to elevated air pollution levels can make people more susceptible to allergies or result in more severe allergic reactions for people with an already pronounced sensitivity to pollen. The aim of this study was to investigate the relationships between urban air pollution (nitrogen oxides, ozone and particles) and airborne Betula pollen in Gothenburg, Sweden, during the pollen seasons for the years 2001-2012. Further, the influence from atmospheric weather pattern on pollen/pollution related risk, using Lamb Weather Types (LWT), was also considered. Daily LWTs were obtained by comparing the variation in atmospheric pressure from a 16 point grid over a given region on earth (scale ~1000km) and essentially describe the air mass movement for the region. They include two non-directional types, cyclonic (C) and anticyclonic (A) and eight directional types depending on the wind direction (N, NE, E... etc.). LWTs with dry and calm meteorological character e.g. limited precipitation and low to moderate wind speeds (A, NE, E, SE) were associated with strongly elevated air pollution and pollen levels where Betula was exceptionally high in LWTs NE and E. The co-variation between Betula pollen and ozone was strong and significant during situations with LWTs A, NE, E and SE. The most important conclusion from this study was that LWTs A, NE, E and SE were associated with high pollen and air pollution levels and can therefore be classified as high risk weather situations for combined air pollution and pollen exposure. Our study shows that LWTs have the potential to be developed into an objective tool for integrated air quality forecasting and a warning system for risk of high exposure situations.

Using machine learning to identify air pollution exposure profiles associated with early cognitive skills among U.S. children.

PubMed

Stingone, Jeanette A; Pandey, Om P; Claudio, Luz; Pandey, Gaurav

2017-11-01

Data-driven machine learning methods present an opportunity to simultaneously assess the impact of multiple air pollutants on health outcomes. The goal of this study was to apply a two-stage, data-driven approach to identify associations between air pollutant exposure profiles and children's cognitive skills. Data from 6900 children enrolled in the Early Childhood Longitudinal Study, Birth Cohort, a national study of children born in 2001 and followed through kindergarten, were linked to estimated concentrations of 104 ambient air toxics in the 2002 National Air Toxics Assessment using ZIP code of residence at age 9 months. In the first-stage, 100 regression trees were learned to identify ambient air pollutant exposure profiles most closely associated with scores on a standardized mathematics test administered to children in kindergarten. In the second-stage, the exposure profiles frequently predicting lower math scores were included within linear regression models and adjusted for confounders in order to estimate the magnitude of their effect on math scores. This approach was applied to the full population, and then to the populations living in urban and highly-populated urban areas. Our first-stage results in the full population suggested children with low trichloroethylene exposure had significantly lower math scores. This association was not observed for children living in urban communities, suggesting that confounding related to urbanicity needs to be considered within the first-stage. When restricting our analysis to populations living in urban and highly-populated urban areas, high isophorone levels were found to predict lower math scores. Within adjusted regression models of children in highly-populated urban areas, the estimated effect of higher isophorone exposure on math scores was -1.19 points (95% CI -1.94, -0.44). Similar results were observed for the overall population of urban children. This data-driven, two-stage approach can be applied to other populations, exposures and outcomes to generate hypotheses within high-dimensional exposure data. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere.

PubMed

Gorski, Galen; Strong, Courtenay; Good, Stephen P; Bares, Ryan; Ehleringer, James R; Bowen, Gabriel J

2015-03-17

Anthropogenic modification of the water cycle involves a diversity of processes, many of which have been studied intensively using models and observations. Effective tools for measuring the contribution and fate of combustion-derived water vapor in the atmosphere are lacking, however, and this flux has received relatively little attention. We provide theoretical estimates and a first set of measurements demonstrating that water of combustion is characterized by a distinctive combination of H and O isotope ratios. We show that during periods of relatively low humidity and/or atmospheric stagnation, this isotopic signature can be used to quantify the concentration of water of combustion in the atmospheric boundary layer over Salt Lake City. Combustion-derived vapor concentrations vary between periods of atmospheric stratification and mixing, both on multiday and diurnal timescales, and respond over periods of hours to variations in surface emissions. Our estimates suggest that up to 13% of the boundary layer vapor during the period of study was derived from combustion sources, and both the temporal pattern and magnitude of this contribution were closely reproduced by an independent atmospheric model forced with a fossil fuel emissions data product. Our findings suggest potential for water vapor isotope ratio measurements to be used in conjunction with other tracers to refine the apportionment of urban emissions, and imply that water vapor emissions associated with combustion may be a significant component of the water budget of the urban boundary layer, with potential implications for urban climate, ecohydrology, and photochemistry.

Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere

PubMed Central

Gorski, Galen; Strong, Courtenay; Good, Stephen P.; Bares, Ryan; Ehleringer, James R.; Bowen, Gabriel J.

2015-01-01

Anthropogenic modification of the water cycle involves a diversity of processes, many of which have been studied intensively using models and observations. Effective tools for measuring the contribution and fate of combustion-derived water vapor in the atmosphere are lacking, however, and this flux has received relatively little attention. We provide theoretical estimates and a first set of measurements demonstrating that water of combustion is characterized by a distinctive combination of H and O isotope ratios. We show that during periods of relatively low humidity and/or atmospheric stagnation, this isotopic signature can be used to quantify the concentration of water of combustion in the atmospheric boundary layer over Salt Lake City. Combustion-derived vapor concentrations vary between periods of atmospheric stratification and mixing, both on multiday and diurnal timescales, and respond over periods of hours to variations in surface emissions. Our estimates suggest that up to 13% of the boundary layer vapor during the period of study was derived from combustion sources, and both the temporal pattern and magnitude of this contribution were closely reproduced by an independent atmospheric model forced with a fossil fuel emissions data product. Our findings suggest potential for water vapor isotope ratio measurements to be used in conjunction with other tracers to refine the apportionment of urban emissions, and imply that water vapor emissions associated with combustion may be a significant component of the water budget of the urban boundary layer, with potential implications for urban climate, ecohydrology, and photochemistry. PMID:25733906

Walls talk: Microbial biogeography of homes spanning urbanization

PubMed Central

Ruiz-Calderon, Jean F.; Cavallin, Humberto; Song, Se Jin; Novoselac, Atila; Pericchi, Luis R.; Hernandez, Jean N.; Rios, Rafael; Branch, Oralee H.; Pereira, Henrique; Paulino, Luciana C.; Blaser, Martin J.; Knight, Rob; Dominguez-Bello, Maria G.

2016-01-01

Westernization has propelled changes in urbanization and architecture, altering our exposure to the outdoor environment from that experienced during most of human evolution. These changes might affect the developmental exposure of infants to bacteria, immune development, and human microbiome diversity. Contemporary urban humans spend most of their time indoors, and little is known about the microbes associated with different designs of the built environment and their interaction with the human immune system. This study addresses the associations between architectural design and the microbial biogeography of households across a gradient of urbanization in South America. Urbanization was associated with households’ increased isolation from outdoor environments, with additional indoor space isolation by walls. Microbes from house walls and floors segregate by location, and urban indoor walls contain human bacterial markers of space use. Urbanized spaces uniquely increase the content of human-associated microbes—which could increase transmission of potential pathogens—and decrease exposure to the environmental microbes with which humans have coevolved. PMID:26933683

Atmospheric bulk deposition of polycyclic aromatic hydrocarbons in Shanghai: Temporal and spatial variation, and global comparison.

PubMed

Feng, Daolun; Liu, Ying; Gao, Yi; Zhou, Jinxing; Zheng, Lirong; Qiao, Gang; Ma, Liming; Lin, Zhifen; Grathwohl, Peter

2017-11-01

Atmospheric deposition leads to accumulation of atmospheric polycyclic aromatic hydrocarbons (PAHs) on urban surfaces and topsoils. To capture the inherent variability of atmospheric deposition of PAHs in Shanghai's urban agglomeration, 85 atmospheric bulk deposition samples and 7 surface soil samples were collected from seven sampling locations during 2012-2014. Total fluxes of 17 PAHs were 587-32,300 ng m -2 day -1 , with a geometric mean of 2600 ng m -2 day -1 . The deposition fluxes were categorized as moderate to high on a global scale. Phenanthrene, fluoranthene and pyrene were major contributors. The spatial distribution of deposition fluxes revealed the influence of urbanization/industrialization and the relevance of local emissions. Meteorological conditions and more heating demand in cold season lead to a significant increase of deposition rates. Atmospheric deposition is the principal pathway of PAHs input to topsoils and the annual deposition load in Shanghai amounts to ∼4.5 tons (0.7 kg km -2 ) with a range of 2.5-10 tons (0.4-1.6 kg km -2 ). Copyright © 2017 Elsevier Ltd. All rights reserved.

Impact of atmospheric particulate matter pollutants to IAQ of airport terminal buildings: A first field study at Tianjin Airport, China

NASA Astrophysics Data System (ADS)

Ren, Jianlin; Cao, Xiaodong; Liu, Junjie

2018-04-01

Passengers usually spend hours in the airport terminal buildings waiting for their departure. During the long waiting period, ambient fine particles (PM2.5) and ultrafine particles (UFP) generated by airliners may penetrate into terminal buildings through open doors and the HVAC system. However, limited data are available on passenger exposure to particulate pollutants in terminal buildings. We conducted on-site measurements on PM2.5 and UFP concentration and the particle size distribution in the terminal building of Tianjin Airport, China during three different seasons. The results showed that the PM2.5 concentrations in the terminal building were considerably larger than the values guided by Chinese standard and WHO on all of the tested seasons, and the conditions were significantly affected by the outdoor air (Spearman test, p < 0.01). The indoor/outdoor PM2.5 ratios (I/O) ranged from 0.67 to 0.84 in the arrival hall and 0.79 to 0.96 in the departure hall. The particle number concentration in the terminal building presented a bi-modal size distribution, with one mode being at 30 nm and another mode at 100 nm. These results were totally different from the size distribution measured in a normal urban environment. The total UFP exposure during the whole waiting period (including in the terminal building and airliner cabin) of a passenger is approximately equivalent to 11 h of exposure to normal urban environments. This study is expected to contribute to the improvement of indoor air quality and health of passengers in airport terminal buildings.

Stable isotopic indicators of nitrous oxide and methane sources in Los Angeles, California

NASA Astrophysics Data System (ADS)

Townsend-Small, A.; Pataki, D.; Tyler, S.; Trumbore, S.

2008-12-01

As urbanization increasingly encroaches upon agricultural landscapes, there are greater potential sources of greenhouse gases and other atmospheric contaminants. Measurements of the isotopic composition of trace gases have the potential to distinguish between pollutant sources and quantify the proportional contribution of agricultural activities to the total atmospheric pool. In this study, we are measuring the isotopic composition of greenhouse gases N2O and CH4 emitted from cropland, animal feeding operations, and urban activities in the South Coast Air Basin in southern California. The ultimate goal of our project is to utilize atmospheric measurements of the isotopic composition of N2O and CH4 combined with studies of source signatures to determine the proportional contributions of cropland, animal operations, and urban sources of greenhouse gases to the atmosphere. Measurements of the δ13C of methane show excellent separation between urban sources, such as vehicle emissions, power plants, oil refineries, landfills, and sewage treatment plants and agricultural sources like cows, biogas, and cattle feedlots. For nitrous oxide, soil N2O sources showed good separation from wastewater treatment facilities using δ15N and δ18O. Within soil N2O sources, the isotopic composition of N2O from cropland soils was similar to N2O emissions from urban turfgrass. These data indicate that nitrification may be as important a source of N2O as denitrification in urban soils. We are also measuring N2O fluxes from soils and from sewage treatment processes, and preliminary data indicate that urban N2O fluxes are higher than initially assumed by managers and regulatory agencies.

Analysis of diurnal variability of atmospheric halocarbons and CFC replacements to imply emission strength and sources at an urban site of Lukang in central Taiwan

NASA Astrophysics Data System (ADS)

Lee, Bing-Sun; Chiou, Chung-Biau; Lin, Chung-Yi

2014-12-01

Hourly atmospheric measurements of halocarbons and chlorofluorocarbon (CFC) replacements were conducted at an urban site of Lukang, Changhua, in central Taiwan from May to August, 2013. The temporal distribution of different groups of halocarbons in the Lukang urban atmosphere, including chlorofluorocarbons (CFCs), Chlorodifluoromethane (HCFC-22), Bromochlorodifluoromethane (Halon-1211), and other chlorinated compounds, is presented and discussed. The concentrations (mixing ratios) of HCFC-22, Dichlorodifluoromethane (CFC-12), Halon-1211, Trichlorofluoromethane (CFC-11), Dichloromethane (CH2Cl2), and Trichloroethylene (TCE) were enhanced with respect to the local background levels; the atmospheric mixing ratio of carbon tetrachloride (CCl4) was slightly higher than its local background level; on the other hand, 1,1,2-Trichlorotrifluoroethane (CFC-113) was relatively uniform and not very different from background atmospheric level in non-urban areas. Among these compounds, HCFC-22, Halon-1211 and the halogenated compounds, CH2Cl2 and TCE, used as solvents were strongly enhanced. The average mixing ratio of Halon-1211 was higher than the local background of ∼4.5 ppt by ∼60% although Halon-1211 production had been phased out by 1996. Hourly average mixing ratios of halocarbons (HCFC-22, CFC-12, Halon-1211, CFC-11, CH2Cl2, and TCE) illustrated a distinct diurnal cycle characterized with a pattern of elevated mixing ratio and large mixing ratio variability amplitude at night relative to that in daytime. Although emission sources of these halocarbons were complex, hourly average mixing ratios for most of these high variability halocarbons peaked at ∼5:00 AM when the hourly average wind speed reached the minimum value of the day; by contrast, the hourly average mixing ratio of CO peaked at ∼8:30 AM when the ambient atmospheric wind condition was strongly influenced by sea breezes during the traffic rush hours. This phenomenon revealed that meteorological factors predominated the distribution of halocarbon mixing ratio in the urban atmosphere and the traffic emission of CFC-12 derived from old vehicles manufactured before 1994 was insignificant to the CFC-12 mixing ratio in the urban atmosphere. The meteorological condition of nighttime atmospheric temperature inversion and low wind speed facilitated the accumulation of terrestrial airborne pollutants near the ground; consequently the hourly average mixing ratios at night were higher than those in daytime by up to ∼2% (CFC-11), ∼7% (CFC-12), ∼75% (HCFC-22), ∼72% (Halon-1211), ∼280% (CH2Cl2), and ∼155% (TCE).

Mesoscale simulations of atmospheric flow and tracer transport in Phoenix, Arizona

NASA Astrophysics Data System (ADS)

Wang, Ge; Ostoja-Starzewski, Martin

2006-09-01

Large urban centres located within confining rugged or complex terrain can frequently experience episodes of high concentrations of lower atmospheric pollution. Metropolitan Phoenix, Arizona (United States), is a good example, as the general population is occasionally subjected to high levels of lower atmospheric ozone, carbon monoxide and suspended particulate matter. As a result of dramatic but continuous increase in population, the accompanying environmental stresses and the local atmospheric circulation that dominates the background flow, an accurate simulation of the mesoscale pollutant transport across Phoenix and similar urban areas is becoming increasingly important. This is particularly the case in an airshed, such as that of Phoenix, where the local atmospheric circulation is complicated by the complex terrain of the area.

A Low Cost High Density Sensor Network for Air Quality at London Heathrow Airport

NASA Astrophysics Data System (ADS)

Bright, V.; Mead, M. I.; Popoola, O. A.; Baron, R. P.; Saffell, J.; Stewart, G.; Kaye, P.; Jones, R.

2012-12-01

Atmospheric composition within urban areas has a direct effect on the air quality of an environment in which a large majority of people live and work. Atmospheric pollutants including ozone (O3), nitrogen dioxide (NO2), volatile organic compounds (VOCs) and particulate matter (PM) can have a significant effect on human health. As such it is important to determine the potential exposure of individuals to these atmospheric constituents and investigate the processes that lead to the degradation of air quality within the urban environment. Whilst modelled pollutant levels on the local scale often suggest high degrees of spatial and temporal variability, the relatively sparse fixed site automated urban networks only provide low spatial resolution data that do not appear adequate in detecting such small scale variability. In this paper we demonstrate that measurements can now be made using networks of low-cost sensors that utilise a variety of techniques, including electrochemical and optical, to measure concentrations of atmospheric species. Once equipped with GPS and GPRS to determine position and transmit data respectively, these networks have the potential to provide valuable insights into pollutant variability inherent on the local or micro-scale. The methodology has been demonstrated successfully in field campaigns carried out in cities including London and Valencia, and is now being deployed as part of the Sensor Networks for Air Quality currently deployed at London Heathrow airport (SNAQ-Heathrow) which is outlined in the partner paper presented by Mead et al. (this conference). The SNAQ-Heathrow network of 50 sensor nodes will provide an unprecedented data set that includes measurements of O3, NO, NO2, CO, CO2, SO2, total VOCs, size-speciated PM as well as meteorological variables that include temperature, relative humidity, wind speed and direction. This network will provide high temporal (20 second intervals) and spatial (50 sites within the airport area) resolution data over a 12 month period with data transmitted back to a server every 2 hours. In this paper we present the data capture and storage, data accessibility, data mining and visualisation techniques applied to the measurements of the SNAQ Heathrow high density sensor network, the preliminary results of which provide an insight into the potential use of such networks in characterising air quality, emissions and validating dispersion models on local scales. We also present a web based interface developed for the sensor network that allows users to access archived data and assess meteorological conditions, atmospheric dispersion, pollutant levels and emission rates.

Unexpected increase in the oxidation capacity of the urban atmosphere of Madrid, Spain.

PubMed

Saiz-Lopez, A; Borge, R; Notario, A; Adame, J A; Paz, D de la; Querol, X; Artíñano, B; Gómez-Moreno, F J; Cuevas, C A

2017-04-11

Atmospheric oxidants such as ozone (O 3 ), hydroxyl and nitrate radicals (OH and NO 3 ) determine the ability of the urban atmosphere to process organic and inorganic pollutants, which have an impact on air quality, environmental health and climate. Madrid city has experienced an increase of 30-40% in ambient air O 3 levels, along with a decrease of 20-40% in NO 2 , from 2007 to 2014. Using air pollution observations and a high-resolution air quality model, we find a large concentration increase of up to 70% and 90% in OH and NO 3 , respectively, in downtown Madrid (domain-wide average increase of 10% and 32% for OH and NO 3 , respectively). The results also show an 11% reduction in the nitric acid concentrations, leading to a remarkable denoxification of this urban atmosphere with implications for lower PM 2.5 levels and nitrogen input into ecosystems. This study suggests that projected worldwide NO x emission reductions, following air quality standards, will lead to important changes in the oxidizing capacity of the atmosphere in and around large cities.

Unexpected increase in the oxidation capacity of the urban atmosphere of Madrid, Spain

NASA Astrophysics Data System (ADS)

Saiz-Lopez, A.; Borge, R.; Notario, A.; Adame, J. A.; Paz, D. De La; Querol, X.; Artíñano, B.; Gómez-Moreno, F. J.; Cuevas, C. A.

2017-04-01

Atmospheric oxidants such as ozone (O3), hydroxyl and nitrate radicals (OH and NO3) determine the ability of the urban atmosphere to process organic and inorganic pollutants, which have an impact on air quality, environmental health and climate. Madrid city has experienced an increase of 30-40% in ambient air O3 levels, along with a decrease of 20-40% in NO2, from 2007 to 2014. Using air pollution observations and a high-resolution air quality model, we find a large concentration increase of up to 70% and 90% in OH and NO3, respectively, in downtown Madrid (domain-wide average increase of 10% and 32% for OH and NO3, respectively). The results also show an 11% reduction in the nitric acid concentrations, leading to a remarkable denoxification of this urban atmosphere with implications for lower PM2.5 levels and nitrogen input into ecosystems. This study suggests that projected worldwide NOx emission reductions, following air quality standards, will lead to important changes in the oxidizing capacity of the atmosphere in and around large cities.

Unexpected increase in the oxidation capacity of the urban atmosphere of Madrid, Spain

PubMed Central

Saiz-Lopez, A.; Borge, R.; Notario, A.; Adame, J. A.; Paz, D. de la; Querol, X.; Artíñano, B.; Gómez-Moreno, F. J.; Cuevas, C. A.

2017-01-01

Atmospheric oxidants such as ozone (O3), hydroxyl and nitrate radicals (OH and NO3) determine the ability of the urban atmosphere to process organic and inorganic pollutants, which have an impact on air quality, environmental health and climate. Madrid city has experienced an increase of 30–40% in ambient air O3 levels, along with a decrease of 20–40% in NO2, from 2007 to 2014. Using air pollution observations and a high-resolution air quality model, we find a large concentration increase of up to 70% and 90% in OH and NO3, respectively, in downtown Madrid (domain-wide average increase of 10% and 32% for OH and NO3, respectively). The results also show an 11% reduction in the nitric acid concentrations, leading to a remarkable denoxification of this urban atmosphere with implications for lower PM2.5 levels and nitrogen input into ecosystems. This study suggests that projected worldwide NOx emission reductions, following air quality standards, will lead to important changes in the oxidizing capacity of the atmosphere in and around large cities. PMID:28397785

The changing face of urban air pollution

NASA Astrophysics Data System (ADS)

Lewis, Alastair C.

2018-02-01

The atmospheric chemistry that leads to photochemical smog and climate-active aerosols requires the presence of volatile organic compounds (VOCs) (1, 2). The VOCs in urban air typically derive from the prevailing energy and transport technologies as well as the use of petrochemical-derived products. On page 760 of this issue, McDonald et al. (3) report that a notable change in emissions may be underway in U.S. cities, with effects on secondary pollutants such as organic aerosols. Shifting from an urban atmosphere dominated by transport-related VOCs to one dominated by VOCs from coatings, adhesives, and consumer products would alter predictions of urban air quality and challenge the existing policy framework for emissions control.

The Canadian Urban Environmental Health Research Consortium - a protocol for building a national environmental exposure data platform for integrated analyses of urban form and health.

PubMed

Brook, Jeffrey R; Setton, Eleanor M; Seed, Evan; Shooshtari, Mahdi; Doiron, Dany

2018-01-08

Multiple external environmental exposures related to residential location and urban form including, air pollutants, noise, greenness, and walkability have been linked to health impacts or benefits. The Canadian Urban Environmental Health Research Consortium (CANUE) was established to facilitate the linkage of extensive geospatial exposure data to existing Canadian cohorts and administrative health data holdings. We hypothesize that this linkage will enable investigators to test a variety of their own hypotheses related to the interdependent associations of built environment features with diverse health outcomes encompassed by the cohorts and administrative data. We developed a protocol for compiling measures of built environment features that quantify exposure; vary spatially on the urban and suburban scale; and can be modified through changes in policy or individual behaviour to benefit health. These measures fall into six domains: air quality, noise, greenness, weather/climate, and transportation and neighbourhood factors; and will be indexed to six-digit postal codes to facilitate merging with health databases. Initial efforts focus on existing data and include estimates of air pollutants, greenness, temperature extremes, and neighbourhood walkability and socioeconomic characteristics. Key gaps will be addressed for noise exposure, with a new national model being developed, and for transportation-related exposures, with detailed estimates of truck volumes and diesel emissions now underway in selected cities. Improvements to existing exposure estimates are planned, primarily by increasing temporal and/or spatial resolution given new satellite-based sensors and more detailed national air quality modelling. Novel metrics are also planned for walkability and food environments, green space access and function and life-long climate-related exposures based on local climate zones. Critical challenges exist, for example, the quantity and quality of input data to many of the models and metrics has changed over time, making it difficult to develop and validate historical exposures. CANUE represents a unique effort to coordinate and leverage substantial research investments and will enable a more focused effort on filling gaps in exposure information, improving the range of exposures quantified, their precision and mechanistic relevance to health. Epidemiological studies may be better able to explore the common theme of urban form and health in an integrated manner, ultimately contributing new knowledge informing policies that enhance healthy urban living.

Horizontal Advection and Mixing of Pollutants in the Urban Atmospheric Environment

NASA Astrophysics Data System (ADS)

Magnusson, S. P.; Entekhabi, D.; Britter, R.; Norford, L.; Fernando, H. J.

2013-12-01

Although urban air quality and its impacts on the public health have long been studied, the increasing urbanization is raising concerns on how to better control and mitigate these health impacts. A necessary element in predicting exposure levels is fundamental understanding of flow and dispersion in urban canyons. The complex topology of building structures and roads requires the resolution of turbulence phenomena within urban canyons. The use of dense and low porosity construction material can lead to rapid heating in response to direct solar exposure due to large thermal mass. Hence thermal and buoyancy effects may be as important as mechanically-forced or shear-induced flows. In this study, the transport of pollutants within the urban environment, as well as the thermal and advection effects, are investigated. The focus is on the horizontal transport or the advection effects within the urban environment. With increased urbanization and larger and more spread cities, concern about how the upstream air quality situation can affect downstream areas. The study also examines the release and the dispersion of hazardous material. Due to the variety and complexity of urban areas around the world, the urban environment is simplified into adjacent two-dimensional urban street canyons. Pollutants are released inside each canyon. Computational Fluid Dynamics (CFD) simulations are applied to evaluate and quantify the flow rate out of each canyon and also the exchange of pollutants between the canyons. Imagine a row of ten adjacent urban street canyons of aspect ratio 1 with horizontal flow perpendicular to it as shown in the attached figure. C is the concentration of pollutants. The first digit indicates in what canyon the pollutant is released and the second digit indicates the location of that pollutant. For example, C3,4 is the concentration of pollutant released inside canyon 3 measured in canyon 4. The same amount of pollution is released inside the ten street canyons. Some amount of the released material in each canyon is transported to its downstream canyons. For example if the most downstream canyon (number 10) is considered, pollutants released inside its upstream canyons are transported to it. For the neutral case (density of air and pollutants is the same), preliminary simulations show that the pollution concentration in the tenth canyon increases by 50% due to its nine upstream canyons. Also in the tenth canyon C9,10/C10,10 is equal to 10%. More simulations are being performed for canyons of various aspect ratios and density differences between the air and the pollutants. Accidental release of hazardous materials or chemical attacks can lead to necessary evacuation of people from cities. Knowing the spread of pollutants and particles within the urban environment can be crucial for engineers working on evacuation plans for cities. The ten adjacent canyons. Material is released inside each canyon.

Air Quality Modeling in Support of the Near-road EXposures and effects of Urban air pollutants Study (NEXUS)

EPA Science Inventory

The paper presents the results of the model applications to estimate exposure metrics in support of an epidemiologic study in Detroit, Michigan. The Near-road Exposures to Urban air pollutant Study (NEXUS) design includes determining if children in Detroit, MI with asthma living ...

Hybrid Air Quality Modeling Approach For Use in the Near-Road Exposures to Urban Air Pollutant Study (NEXUS)

EPA Science Inventory

The Near-road EXposures to Urban air pollutant Study (NEXUS) investigated whether children with asthma living in close proximity to major roadways in Detroit, MI, (particularly near roadways with high diesel traffic) have greater health impacts associated with exposure to air pol...

The Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS): Study Design and Methods

EPA Science Inventory

The Near-road EXposures and effects of urban air pollutants Study (NEXUS) was designed to examine the relationship between near-roadway exposures to air pollutants and respiratory outcomes in a cohort of asthmatic children who live close to major roadways in Detroit, Michigan USA...

Airborne dust absorption by semi-arid forests reduces PM pollution in nearby urban environments.

PubMed

Uni, Daphna; Katra, Itzhak

2017-11-15

Dust storms are a major source of global atmospheric particulate matter (PM), having significant impacts on air pollution and human health. During dust storms, daily averages of atmospheric PM concentrations can reach high levels above the World Health Organization (WHO) guideline for air quality. The objective of this study was to explore the impact of forests on PM distribution following dust events in a region that is subjected to frequent dust storms (Northern Negev, Israel). Dust was measured in a forest transect including urban environments that are nearby the forest and at a distal location. During a background period, without dust events, the forest with its surrounding areas were characterized by lower monthly average of PM concentrations (38μg/m 3 ) compared with areas that are not affected by the forest (54μg/m 3 ). Such difference can be meaningful for long-term human health exposure. A reduction in PM levels in the forest transect was evident at most measured dust events, depending on the storm intensity and the locations of the protected areas. A significant reduction in PM 2.5 /PM 10 during dust events, indicates the high efficiency of the forest trees to absorb airborne PM 2.5 . Analysis of dust particles absorbed on the foliage revealed a total dust deposits of 8.1-9.2g/m 2 , which is equal to a minimum of 418.2tons removed from the atmosphere per a forest foliage area (30km 2 ). The findings can support environmental strategies to enhance life quality in regions that are subjected to dust storms, or under potential risk of dust-related PM due to land use and/or climate changes. Copyright © 2017 Elsevier B.V. All rights reserved.

Using an epiphytic moss to identify previously unknown sources of atmospheric cadmium pollution.

PubMed

Donovan, Geoffrey H; Jovan, Sarah E; Gatziolis, Demetrios; Burstyn, Igor; Michael, Yvonne L; Amacher, Michael C; Monleon, Vicente J

2016-07-15

Urban networks of air-quality monitors are often too widely spaced to identify sources of air pollutants, especially if they do not disperse far from emission sources. The objectives of this study were to test the use of moss bio-indicators to develop a fine-scale map of atmospherically-derived cadmium and to identify the sources of cadmium in a complex urban setting. We collected 346 samples of the moss Orthotrichum lyellii from deciduous trees in December, 2013 using a modified randomized grid-based sampling strategy across Portland, Oregon. We estimated a spatial linear model of moss cadmium levels and predicted cadmium on a 50m grid across the city. Cadmium levels in moss were positively correlated with proximity to two stained-glass manufacturers, proximity to the Oregon-Washington border, and percent industrial land in a 500m buffer, and negatively correlated with percent residential land in a 500m buffer. The maps showed very high concentrations of cadmium around the two stained-glass manufacturers, neither of which were known to environmental regulators as cadmium emitters. In addition, in response to our findings, the Oregon Department of Environmental Quality placed an instrumental monitor 120m from the larger stained-glass manufacturer in October, 2015. The monthly average atmospheric cadmium concentration was 29.4ng/m(3), which is 49 times higher than Oregon's benchmark of 0.6ng/m(3), and high enough to pose a health risk from even short-term exposure. Both stained-glass manufacturers voluntarily stopped using cadmium after the monitoring results were made public, and the monthly average cadmium levels precipitously dropped to 1.1ng/m(3) for stained-glass manufacturer #1 and 0.67ng/m(3) for stained-glass manufacturer #2. Published by Elsevier B.V.

Addressing the impact of urban exposure on the incidence of type 2 diabetes mellitus: The PERU MIGRANT Study.

PubMed

Ruiz-Alejos, Andrea; Carrillo-Larco, Rodrigo M; Miranda, J Jaime; Anderson, Cheryl A M; Gilman, Robert H; Smeeth, Liam; Bernabé-Ortiz, Antonio

2018-04-03

The aim of this study was to estimate the incidence of T2DM in three population groups: rural, rural-to-urban migrants and urban dwellers. Data from the PERU MIGRANT Study was analysed. The baseline assessment was conducted in 2007-2008 using a single-stage random sample and further follow-up was undertaken in 2015-16. T2DM was defined based on fasting glucose and self-reported diagnosis. Poisson regression models and robust variance to account for cluster effects were used for reporting risk ratios (RR) and 95%CI. At baseline, T2DM prevalence was 8% in urban, 3.6% in rural-to-urban migrants and 1.5% in rural dwellers. After 7.7 (SD: 1.1) years, 6,076 person-years of follow-up, 61 new cases were identified. The incidence rates in the urban, migrant and rural groups were 1.6, 0.9 and 0.5 per 100 person-years, respectively. Relative to rural dwellers, a 4.3-fold higher risk (95%CI: 1.6-11.9) for developing T2DM was found in urban dwellers and 2.7-fold higher (95%CI: 1.1-6.8) in migrants with ≥30 years of urban exposure. Migration and urban exposure were found as significant risk factors for developing T2DM. Within-country migration is a sociodemographic phenomenon occurring worldwide; thus, it is necessary to disentangle the effect of urban exposure on non-healthy habits and T2DM development.

Patterns and Drivers of Inorganic and Organic Nitrogen and Phosphorus Deposition, Cycling, and Loss Throughout a Metropolitan Area

NASA Astrophysics Data System (ADS)

Decina, S.; Templer, P. H.; Hutyra, L.; Gately, C.

2016-12-01

As the urban population expands to 70% of the global population by the year 2050, it is essential to understand changes in both nitrogen (N) and phosphorus (P) cycling in urban ecosystems. Though rates of atmospheric N deposition have been shown to be elevated in numerous cities, few studies have discerned patterns and drivers of spatial variation within urban areas, nor examined rates of urban P deposition or the organic components of both N and P cycling in these ecosystems. We measured atmospheric inorganic N deposition, soil N cycling and loss, and soil respiration across the greater Boston area in the growing seasons of 2015 and 2016, as well as atmospheric deposition and loss of total (inorganic + organic) N and P in the growing season of 2016. We find that mean rates of inorganic N deposition in the greater Boston area are 8.70 ± 0.68 kg N ha-1 yr-1, which is almost double the rate of N deposition measured at a rural reference site 90 km southwest of Boston. Moreover, rates of N deposition are highly variable, varying from 3.84 to 13.82 kg N ha-1 yr-1 within the greater Boston area. Ammonium (NH4+) deposition composes 69.9 ± 2.2 % of total inorganic N deposition, is highest in late spring, and is strongly correlated with traffic emissions of nitrogen oxides (NOx) and distance to roads, which suggests a strong effect of vehicular ammonia (NH3) emissions and spring fertilizer application on urban N deposition. In contrast to past studies, we do not find significant relationships between rates of atmospheric N deposition with N loss via leaching, nor with rates of soil respiration. These results indicate that studies and networks measuring urban N deposition should make measurements across many sites, urban NH3 emissions should be monitored and modeled to predict and explain the variability in urban N deposition fluxes, and N deposition is decoupled from soil N and C loss in urban areas. Overall, our findings demonstrate that urban areas have distinct patterns and drivers of the biogeochemical cycling of nutrients, particularly N and P.

The determination and role of peroxyacetil nitrate in photochemical processes in atmosphere

PubMed Central

2012-01-01

Peroxyacetilnitrates (PAN) is the most characteristic photoxidant of a range of secondary pollutants formed by the photochemical reaction of hydrocarbons with nitrogen oxides in the atmosphere: it is phytotoxic and shows an increasing role in human health effects due to ambient air exposure, especially in presence of high ozone concentrations. Because of the similarity of the conditions required for their photochemical production PAN is observed in conjunction with elevated ozone concentrations. PAN has very low natural background concentrations so it is the very specific indicator of anthropogenic photochemical air pollution. In this paper we report PAN concentrations determined in Rome urban area during winter- and summer-period. PAN measurements were carried out by means of a gas-chromatograph equipped with an Electron Capture Detector (ECD) detector. For identifying the acute episodes of atmospheric photochemical pollutants the relationship between PAN and the variable Ox (=NO2+O3) which describes the oxidation process evolution is investigated. The role of Volatile Organic Compounds and PAN in the ozone formation is investigated as well the issue of taking in account the autovehicular emissions for checking the NOx fraction in fuel. PMID:22594443

Urban UV environment in a sub-tropical megacity - A measurement and modelling study

NASA Astrophysics Data System (ADS)

Wai, Ka-Ming; Yu, Peter K. N.; Chan, Pok-Man

The variations of solar total UV (UVA + UVB) exposure rates in a megacity featured with high-rise buildings during summer months were measured and relevant model predictions were evaluated. The maximum pedestrian-level total solar UV exposure rate was less than the un-obstructed exposure rate at any time, attributing to the prevailing reduction in the diffuse solar radiation due to the obstruction effects of distant buildings. Comparing with the measurements, our coupled model well captured the spatial and temporal variations of the reduction of UV exposure rates. By measurements, large reduction in the solar total UV exposure rate down to 12% of un-obstructed exposure rate due to the building obstruction effects was found, agreeing with our previous simulation results and results from an Australian megacity. On the other hand, building reflection from reflective curtain walls could reach 23% of the un-obstructed solar total UV exposure rate at the ground level. This implied improper building design creating additional harmful effects of solar UV radiation on the environment. The coupled model was also applied to predict the urban UV exposure rates during a tropical-cyclone induced aerosol episode. A well-evaluated urban solar UV model is an important tool for sustainable urban design.

Sensitivity study of the UHI in the city of Szeged (Hungary) to different offline simulation set-ups using SURFEX/TEB

NASA Astrophysics Data System (ADS)

Zsebeházi, Gabriella; Hamdi, Rafiq; Szépszó, Gabriella

2015-04-01

Urbanised areas modify the local climate due to the physical properties of surface subjects and their morphology. The urban effect on local climate and regional climate change interact, resulting in more serious climate change impacts (e.g., more heatwave events) over cities. Majority of people are now living in cities and thus, affected by these enhanced changes. Therefore, targeted adaptation and mitigation strategies in cities are of high importance. Regional climate models (RCMs) are sufficient tools for estimating future climate change of an area in detail, although most of them cannot represent the urban climate characteristics, because their spatial resolution is too coarse (in general 10-50 km) and they do not use a specific urban parametrization over urbanized areas. To describe the interactions between the urban surface and atmosphere on few km spatial scale, we use the externalised SURFEX land surface scheme including the TEB urban canopy model in offline mode (i.e. the interaction is only one-way). The driving atmospheric conditions highly influence the impact results, thus the good quality of these data is particularly essential. The overall aim of our research is to understand the behaviour of the impact model and its interaction with the forcing coming from the atmospheric model in order to reduce the biases, which can lead to qualified impact studies of climate change over urban areas. As a preliminary test, several short (few-day) 1 km resolution simulations are carried out over a domain covering a Hungarian town, Szeged, which is located at the flat southern part of Hungary. The atmospheric forcing is provided by ALARO (a new version of the limited-area model of the ARPEGE-IFS system running at the Royal Meteorological Institute of Belgium) applied over Hungary. The focal point of our investigations is the ability of SURFEX to simulate the diurnal evolution and spatial pattern of urban heat island (UHI). Different offline simulation set-ups have been tested: 1. Atmospheric forcing at 4km and 10km resolutions; 2. Atmospheric forcing prepared with and without TEB; 3. Coupling of forcings on 3h and 1h temporal frequencies; 4. Different forcing levels on 50m, 40m, 30m, 20m, 10m; 5. Different computation method of 2m temperature using CANOPY, Paulson, and Geleyn schemes. Finally, some outcomes are also compared to the results obtained using ALADIN-Climate RCM (adapted and used at the Hungarian Meteorological Service on 10 km resolution) as driving atmospheric model. The presentation is dedicated to show the results and main conclusions of our studies.

Diurnal changes in urban boundary layer environment induced by urban greening

NASA Astrophysics Data System (ADS)

Song, Jiyun; Wang, Zhi-Hua

2016-11-01

Urban green infrastructure has been widely used for mitigating adverse environmental problems as well as enhancing urban sustainability of cities worldwide. Here we develop an integrated urban-land-atmosphere modeling framework with the land surface processes parameterized by an advanced urban canopy model and the atmospheric processes parameterized by a single column model. The model is then applied to simulate a variety of forms of green infrastructure, including urban lawns, shade trees, green and cool roofs, and their impact on environmental changes in the total urban boundary layer (UBL) for a stereotypical desert city, viz. Phoenix, Arizona. It was found that green roofs have a relatively uniform cooling effect proportional to their areal coverage. In particular, a reduction of UBL temperature of 0.3 °C and 0.2 °C per 10% increase of green roof coverage was observed at daytime and nighttime, respectively. In contrast, the effect of greening of street canyons is constrained by the overall abundance of green infrastructure and the energy available for evapotranspiration. In addition, the increase in urban greening causes boundary-layer height to decrease during daytime but increase at nighttime, leading to different trends of changes in urban air quality throughout a diurnal cycle.

Airborne Observations of Urban-Derived Water Vapor and Potential Impacts on Chemistry and Clouds

NASA Astrophysics Data System (ADS)

Salmon, O. E.; Shepson, P. B.; Grundman, R. M., II; Stirm, B. H.; Ren, X.; Dickerson, R. R.; Fuentes, J. D.

2015-12-01

Atmospheric conditions typical of wintertime, such as lower boundary layer heights and reduced turbulent mixing, provide a unique environment for anthropogenic pollutants to accumulate and react. Wintertime enhancements in water vapor (H2O) have been observed in urban areas, and are thought to result from fossil fuel combustion and urban heat island-induced evaporation. The contribution of urban-derived water vapor to the atmosphere has the potential to locally influence atmospheric chemistry and weather for the urban area and surrounding region due to interactions between H2O and other chemical species, aerosols, and clouds. Airborne observations of urban-derived H2O, carbon dioxide (CO2), methane, nitrogen dioxide (NO2), ozone, and aerosols were conducted from Purdue University's Airborne Laboratory for Atmospheric Research (ALAR) and the University of Maryland's (UMD) Twin Cessna research aircraft during the winter of 2015. Measurements were conducted as part of the collaborative airborne campaign, Wintertime INvestigation of Transport, Emissions, and Reactivity (WINTER), which investigated seasonal trends in anthropogenic emissions and reactivity in the Northeastern United States. ALAR and the UMD aircraft participated in mass balance experiments around Washington D.C.-Baltimore to determine total city emission rates of H2O and other greenhouse gases. Average enhancements in H2O mixing ratio of 0.048%, and up to 0.13%, were observed downwind of the urban centers on ten research flights. In some cases, downwind H2O concentrations clearly track CO2 and NO2 enhancements, suggesting a strong combustion signal. Analysis of Purdue and UMD data collected during the WINTER campaign shows an average urban-derived H2O contribution of 5.3%, and as much as 13%, to the local boundary layer from ten research flights flown in February and March of 2015. In this paper, we discuss the potential chemical and physical implications of these results.

CO2 dispersion modelling over Paris region within the CO2-MEGAPARIS project

NASA Astrophysics Data System (ADS)

Lac, C.; Donnelly, R. P.; Masson, V.; Pal, S.; Riette, S.; Donier, S.; Queguiner, S.; Tanguy, G.; Ammoura, L.; Xueref-Remy, I.

2013-05-01

Accurate simulation of the spatial and temporal variability of tracer mixing ratios over urban areas is a challenging and interesting task needed to be performed in order to utilise CO2 measurements in an atmospheric inverse framework and to better estimate regional CO2 fluxes. This study investigates the ability of a high-resolution model to simulate meteorological and CO2 fields around Paris agglomeration during the March field campaign of the CO2-MEGAPARIS project. The mesoscale atmospheric model Meso-NH, running at 2 km horizontal resolution, is coupled with the Town Energy Balance (TEB) urban canopy scheme and with the Interactions between Soil, Biosphere and Atmosphere CO2-reactive (ISBA-A-gs) surface scheme, allowing a full interaction of CO2 modelling between the surface and the atmosphere. Statistical scores show a good representation of the urban heat island (UHI) with stronger urban-rural contrasts on temperature at night than during the day by up to 7 °C. Boundary layer heights (BLH) have been evaluated on urban, suburban and rural sites during the campaign, and also on a suburban site over 1 yr. The diurnal cycles of the BLH are well captured, especially the onset time of the BLH increase and its growth rate in the morning, which are essential for tall tower CO2 observatories. The main discrepancy is a small negative bias over urban and suburban sites during nighttime (respectively 45 m and 5 m), leading to a few overestimations of nocturnal CO2 mixing ratios at suburban sites and a bias of +5 ppm. The diurnal CO2 cycle is generally well captured for all the sites. At the Eiffel tower, the observed spikes of CO2 maxima occur every morning exactly at the time at which the atmospheric boundary layer (ABL) growth reaches the measurement height. At suburban ground stations, CO2 measurements exhibit maxima at the beginning and at the end of each night, when the ABL is fully contracted, with a strong spatio-temporal variability. A sensitivity test without urban parameterisation removes the UHI and underpredicts nighttime BLH over urban and suburban sites, leading to large overestimation of nocturnal CO2 mixing ratio at the suburban sites (bias of +17 ppm). The agreement between observation and prediction for BLH and CO2 concentrations and urban-rural increments, both day and night, demonstrates the potential of using the urban mesoscale system in the context of inverse modelling

Technologies to Combat Weapons of Mass Destruction

DTIC Science & Technology

2008-03-12

performance standards across our agencies and our operations, and toxic industrial chemicals and the unique atmospheric condi- tions in an urban environment... chlorine cylinders in improvised explosive devices. While to date these types of attacks have killed fewer people than conventional sui- cide bombs, it...environment include a broad array of chemicals, to include toxic industrial chemicals. The urban environment also has very localized atmospheric

Modeling the Urban Boundary and Canopy Layers

EPA Science Inventory

Today, we are confronted with increasingly more sophisticated application requirements for urban modeling. These include those that address emergency response to acute exposures from toxic releases, health exposure assessments from adverse air quality, energy usage, and character...

Violence Exposure and Depressive Symptoms among Adolescents and Young Adults Disconnected from School and Work

ERIC Educational Resources Information Center

Mendelson, Tamar; Turner, Alezandria K.; Tandon, S. Darius

2010-01-01

The psychological effects of exposure to different types of violence among urban adolescents and young adults are not yet well understood. This study investigated exposure to neighborhood violence, relationship violence, and forced sex among 677 urban African Americans aged 16-23 enrolled at an employment and training center. We assessed…

Patterns of Violence Exposure and Sexual Risk in Low-Income, Urban African American Girls

PubMed Central

Wilson, Helen W.; Woods, Briana A.; Emerson, Erin; Donenberg, Geri R.

2013-01-01

Objective This study examined the relationship between violence exposure and sexual risk-taking among low-income, urban African American (AA) adolescent girls, considering overlap among different types and characteristics of violence. Methods AA adolescent girls were originally recruited from outpatient mental health clinics serving urban, mostly low-SES communities in Chicago, IL as part of a two-year longitudinal investigation of HIV-risk behavior. A subsequent follow-up was completed to assess lifetime history of trauma and violence exposure. The current study (N=177) included violence exposure and sexual risk behavior reported at the most recent interview (ages 14-22). Multiple regression was used to examine combined and unique contributions of different types, ages, settings, and perpetrators or victims of violence to variance in sexual risk. Results More extensive violence exposure and cumulative exposure to different kinds of violence were associated with overall unsafe sex, more partners, and inconsistent condom use. The most significant unique predictors, accounting for overlap among different forms of violence, were physical victimization, adolescent exposure, neighborhood violence, and violence involving dating partners. Conclusions These findings put sexual risk in the context of broad traumatic experiences but also suggest that the type and characteristics of violence exposure matter in terms of sexual health outcomes. Violence exposure should be addressed in efforts to reduce STIs among low-income, urban African American girls. PMID:24563808

Human exposure to environmental health concern by types of urban environment: The case of Tel Aviv.

PubMed

Schnell, Izhak; Potchter, Oded; Yaakov, Yaron; Epstein, Yoram

2016-01-01

This study classifies urban environments into types characterized by different exposure to environmental risk factors measured by general sense of discomfort and Heart Rate Variability (HRV). We hypothesize that a set of environmental factors (micro-climatic, CO, noise and individual heart rate) that were measured simultaneously in random locations can provide a better understanding of the distribution of human exposure to environmental loads throughout the urban space than results calculated based on measurements from close fixed stations. We measured micro-climatic and thermal load, CO and noise, individual Heart Rate, Subjective Social Load and Sense of Discomfort (SD) were tested by questionnaire survey. The results demonstrate significant differences in exposure to environmental factors among 8 types of urban environments. It appears that noise and social load are the more significant environmental factors to enhance health risks and general sense of discomfort. Copyright © 2015 Elsevier Ltd. All rights reserved.

Spatiotemporal distributions of ambient oxides of nitrogen, with implications for exposure inequality and urban design.

PubMed

Yu, Haofei; Stuart, Amy L

2013-08-01

Intra-urban differences in concentrations of oxides of nitrogen (NO(x)) and exposure disparities in the Tampa area were investigated across temporal scales through emissions estimation, dispersion modeling, and analysis of residential subpopulation exposures. A hybrid estimation method was applied to provide link-level hourly on-road mobile source emissions. Ambient concentrations in 2002 at 1 km resolution were estimated using the CALPUFF dispersion model. Results were combined with residential demographic data at the block-group level, to investigate exposures and inequality for select racioethnic, age, and income population subgroups. Results indicate that on-road mobile sources contributed disproportionately to ground-level concentrations and dominated the spatial footprint across temporal scales (annual average to maximum hour). The black, lower income (less than $40K annually), and Hispanic subgroups had higher estimated exposures than the county average; the white and higher income (greater than $60K) subgroups had lower than average exposures. As annual average concentration increased, the disparity between groups generally increased. However for the highest 1-hr concentrations, reverse disparities were also found. Current studies of air pollution exposure inequality have not fully considered differences by time scale and are often limited in spatial resolution. The modeling methods and the results presented here can be used to improve understanding of potential impacts of urban growth form on health and to improve urban sustainability. Results suggest focusing urban design interventions on reducing on-road mobile source emissions in areas with high densities of minority and low income groups.

Pollution characteristics, sources and lung cancer risk of atmospheric polycyclic aromatic hydrocarbons in a new urban district of Nanjing, China.

PubMed

Wang, Tao; Xia, Zhonghuan; Wu, Minmin; Zhang, Qianqian; Sun, Shiqi; Yin, Jing; Zhou, Yanchi; Yang, Hao

2017-05-01

This paper focused on the pollution characteristics, sources and lung cancer risk of atmospheric polycyclic aromatic hydrocarbons (PAHs) in a new urban district of Nanjing, China. Gaseous and aerosol PM 2.5 (particulate matter with aerodynamic diameter smaller than 2.5μm) samples were collected in spring of 2015. Sixteen PAHs were extracted and analyzed after sampling. Firstly, arithmetic mean concentrations of PAHs and BaP eq (benzo[a]pyrene equivalent) were calculated. The mean concentrations of PAHs were 29.26±14.13, 18.14±5.37 and 48.47±16.03ng/m 3 in gas phase, particle phase and both phases, respectively. The mean concentrations of BaP eq were 0.87±0.51, 2.71±2.17 and 4.06±2.31ng/m 3 in gas phase, particle phase and both phases, respectively. Secondly, diagnostic ratios and principal component analysis were adopted to identify the sources of PAHs and the outcomes were the same: traffic exhaust was the predominant source followed by fuel combustion and industrial process. Finally, incremental lung cancer risk (ILCR) induced by whole year inhalation exposure to PAHs for population groups of different age and gender were estimated based on a Monte Carlo simulation. ILCR values caused by particle phase PAHs were greater than those caused by gas phase PAHs. ILCR values for adults were greater than those for other age groups. ILCR values caused by total (gas+particle) PAHs for diverse groups were all greater than the significant level (l0 -6 ), indicating high potential lung cancer risk. Sensitivity analysis results showed that cancer slope factor for BaP inhalation exposure and BaP eq concentration had greater impact than body weight and inhalation rate on the ILCR. Copyright © 2016. Published by Elsevier B.V.

The influence of atmospheric particles on the elemental content of vegetables in urban gardens of Sao Paulo, Brazil.

PubMed

Amato-Lourenco, Luís Fernando; Moreira, Tiana Carla Lopes; de Oliveira Souza, Vanessa Cristina; Barbosa, Fernando; Saiki, Mitiko; Saldiva, Paulo Hilário Nascimento; Mauad, Thais

2016-09-01

Although urban horticulture provides multiple benefits to society, the extent to which these vegetables are contaminated by the absorption of chemical elements derived from atmospheric deposition is unclear. This study was designed to evaluate the influence of air pollution on leafy vegetables in community gardens of Sao Paulo, Brazil. Vegetable seedlings of Brassica oleracea var. acephala (collard greens) and Spinacia oleracea (spinach) obtained in a non-polluted rural area and growing in vessels containing standard uncontaminated soil were exposed for three consecutive periods of 30, 60 and 90 days in 10 community gardens in Sao Paulo and in one control site. The concentrations of 17 chemical elements (traffic-related elements and those essential to plant biology) were quantified by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Tillandsia usneoides L. specimens were used as air plant biomonitors. The concentrations of As, Cd, Cr and Pb found in vegetables were compared to the recommended values for consumption. Principal Component Analysis (PCA) was used to cluster the elemental concentrations, and Generalized Linear Models (GLMs) were employed to evaluate the association of the factor scores from each PCA component with variables such as local weather, traffic burden and vertical barriers adjacent to the gardens. We found significant differences in the elemental concentrations of the vegetables in the different community gardens. These differences were related to the overall traffic burden, vertical obstacles and local weather. The Pb and Cd concentrations in both vegetables exceeded the limit values for consumption after 60 days of exposure. A strong correlation was observed between the concentration of traffic-related elements in vegetables and in Tillandsia usneoides L. An exposure response was observed between traffic burden and traffic-derived particles absorbed in the vegetables. Traffic-derived air pollution directly influences the absorption of chemical elements in leafy vegetables, and the levels of these elements may exceed the recommended values for consumption. Copyright © 2016 Elsevier Ltd. All rights reserved.

Source apportionment of atmospheric bulk deposition in the Belgrade urban area using Positive Matrix factorization

NASA Astrophysics Data System (ADS)

Tasić, M.; Mijić, Z.; Rajšić, S.; Stojić, A.; Radenković, M.; Joksić, J.

2009-04-01

The primary objective of the present study was to assess anthropogenic impacts of heavy metals to the environment by determination of total atmospheric deposition of heavy metals. Atmospheric depositions (wet + dry) were collected monthly, from June 2002 to December 2006, at three urban locations in Belgrade, using bulk deposition samplers. Concentrations of Fe, Al, Pb, Zn, Cu, Ni, Mn, Cr, V, As and Cd were analyzed using atomic absorption spectrometry. Based upon these results, the study attempted to examine elemental associations in atmospheric deposition and to elucidate the potential sources of heavy metal contaminants in the region by the use of multivariate receptor model Positive Matrix Factorization (PMF).

Occupational Exposure to Vapor-Gas, Dust, and Fumes in a Cohort of Rural Adults in Iowa Compared with a Cohort of Urban Adults

PubMed Central

Henneberger, Paul K.; Humann, Michael J.; Liang, Xiaoming; Kelly, Kevin M.; Cox-Ganser, Jean M.

2017-01-01

Problem/Condition Many rural residents work in the field of agriculture; however, employment in nonagricultural jobs also is common. Because previous studies in rural communities often have focused on agricultural workers, much less is known about the occupational exposures in other types of jobs in rural settings. Characterizing airborne occupational exposures that can contribute to respiratory diseases is important so that differences between rural and urban working populations can be assessed. Reporting Period 1994–2011. Description of System This investigation used data from the baseline questionnaire completed by adult rural residents participating in the Keokuk County Rural Health Study (KCRHS). The distribution of jobs and occupational exposures to vapor-gas, dust, and fumes (VGDF) among all participants was analyzed and stratified by farming status (current, former, and never) then compared with a cohort of urban workers from the Multi-Ethnic Study of Atherosclerosis (MESA). Occupational exposure in the last job was assessed with a job-exposure matrix (JEM) developed for chronic obstructive pulmonary disease (COPD). The COPD JEM assesses VGDF exposure at levels of none or low, medium, and high. Results The 1,699 KCRHS (rural) participants were more likely to have medium or high occupational VGDF exposure (43.2%) at their last job than their urban MESA counterparts (15.0% of 3,667 participants). One fifth (20.8%) of the rural participants currently farmed, 43.1% were former farmers, and approximately one third (36.1%) had never farmed. These three farming groups differed in VGDF exposure at the last job, with the prevalence of medium or high exposure at 80.2% for current farmers, 38.7% for former farmers, and 27.4% for never farmers, and all three percentages were higher than the 15.0% medium or high level of VGDF exposure for urban workers. Interpretation Rural workers, including those who had never farmed, were more likely to experience occupational VGDF exposure than urban workers. Public Health Action The occupational exposures of rural adults assessed using the COPD JEM will be used to investigate their potential association with obstructive respiratory health problems (e.g., airflow limitation and chronic bronchitis). This assessment might highlight occupations in need of preventive interventions. PMID:29095802

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

Calderon-Garciduenas, L.; Osnaya-Brizuela, N.; Ramirez-Martinez, L.

All organisms have the ability to respond and adapt to a myriad of environmental insults. The human respiratory epithelium, when exposed to oxidant gases in photochemical smog, is at risk of DNA damage and requires efficient cellular adaptative responses to resist the environmentally induced cell damage. Ozone and its reaction products induce in vitro and in vivo DNA single strand breaks (SSBs) in respiratory epithelial cells and alveolar macrophages. To determine if exposure to a polluted atmosphere with ozone as the main criteria pollutant of 19 children and 13 adult males who lived in a low-polluted Pacific port, 69 malesmore » and 16 children who were permanent residents of Southwest Metropolitan Mexico City (SWMMC), and 22 young males newly arrived to SWMMC and followed for 12 weeks. Respiratory symptoms, nasal cytology and histopathology, cell viabilities, and single-cell gel electrophoresis were investigated. Atmospheric pollutant data were obtained from a fixed-site monitoring station. SWMMC volunteers spent >7 hr/day outdoors and all had upper respiratory symptoms. A significant difference in the numbers of DNA-damaged nasal cells was observed between control and chronically exposed subjects, both in children (p<0.00001) and in adults (p>0.01). SSBs in newly arrived subjects quickly increased upon arrival to the city, from 39.8 {+-}8.34% in the first week to 67.29 {+-}2.35 by week 2. Thereafter, the number of cells with SSBs remained stable in spite of the continuous increase in cumulative ozone, suggesting a threshold for cumulative DNA nasal damage. Exposure to a polluted urban atmosphere induces SSBs in human nasal respiratory epithelium, and nasal SSBs could serve as a biomarker of ozone exposure. Further, because DNA strand breaks are a threat to cell viability and genome integrity and appear to be a critical lesion responsible for p53 induction, nasal SSBs should be evaluated in ozone-exposed individuals. 43 refs., 5 figs., 4 tabs.« less

A review of studies on atmospheric mercury in China.

PubMed

Fu, Xuewu; Feng, Xinbin; Sommar, Jonas; Wang, Shaofeng

2012-04-01

Due to the fast developing economy, mercury (Hg) emissions to the atmosphere from Chinese mainland have increased rapidly in recent years. Consequently, this issue has received a considerable attention internationally. This paper reviews the current understanding of and knowledge on atmospheric Hg emissions, distribution and transport in China. The magnitude of Hg emissions to the atmosphere from Chinese anthropogenic sources has been estimated to be in the range of 500-700 tons per year, whereby comprising a significant proportion of the globe total anthropogenic emissions. Emissions of Hg from natural surfaces including bare soil, water, and vegetation covered soil tend in a comparison to be higher in China than in Europe and North America, indicating the importance of this source category. Atmospheric Hg exhibits a significant concentration variability among urban, semi-remote, and remote areas. Total Gaseous Mercury (TGM) concentrations in urban areas of China were often 1.5 - 5 folds higher compared to the corresponding settings in North America and Europe. In turn, particulate mercury (PHg) concentrations in urban areas of China were up to two orders of magnitude higher compared to North America and Europe. Atmospheric observations made at strictly remote sites in China also include the presence of occasional high concentrations of TGM, and the more short-lived fractions PHg and Reactive Gaseous Mercury (RGM). Accordingly, Hg deposition fluxes tended to be higher in China, with remote areas and urban areas being 1-2 times and 1-2 magnitude higher than those in North America and Europe, respectively. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere

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

Gorski, Galen; Strong, Courtenay; Good, Stephen P.

Anthropogenic modification of the water cycle involves a diversity of processes, many of which have been studied intensively using models and observations. Some effective tools for measuring the contribution and fate of combustion-derived water vapor in the atmosphere are lacking, however, and this flux has received relatively little attention. We provide theoretical estimates and a first set of measurements demonstrating that water of combustion is characterized by a distinctive combination of H and O isotope ratios. Furthermore, we show that during periods of relatively low humidity and/or atmospheric stagnation, this isotopic signature can be used to quantify the concentration ofmore » water of combustion in the atmospheric boundary layer over Salt Lake City. Combustion-derived vapor concentrations vary between periods of atmospheric stratification and mixing, both on multiday and diurnal timescales, and respond over periods of hours to variations in surface emissions. Our estimates suggest that up to 13% of the boundary layer vapor during the period of study was derived from combustion sources, and both the temporal pattern and magnitude of this contribution were closely reproduced by an independent atmospheric model forced with a fossil fuel emissions data product. These findings suggest potential for water vapor isotope ratio measurements to be used in conjunction with other tracers to refine the apportionment of urban emissions, and imply that water vapor emissions associated with combustion may be a significant component of the water budget of the urban boundary layer, with potential implications for urban climate, ecohydrology, and photochemistry.« less

Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere

DOE PAGES

Gorski, Galen; Strong, Courtenay; Good, Stephen P.; ...

2015-03-02

Anthropogenic modification of the water cycle involves a diversity of processes, many of which have been studied intensively using models and observations. Some effective tools for measuring the contribution and fate of combustion-derived water vapor in the atmosphere are lacking, however, and this flux has received relatively little attention. We provide theoretical estimates and a first set of measurements demonstrating that water of combustion is characterized by a distinctive combination of H and O isotope ratios. Furthermore, we show that during periods of relatively low humidity and/or atmospheric stagnation, this isotopic signature can be used to quantify the concentration ofmore » water of combustion in the atmospheric boundary layer over Salt Lake City. Combustion-derived vapor concentrations vary between periods of atmospheric stratification and mixing, both on multiday and diurnal timescales, and respond over periods of hours to variations in surface emissions. Our estimates suggest that up to 13% of the boundary layer vapor during the period of study was derived from combustion sources, and both the temporal pattern and magnitude of this contribution were closely reproduced by an independent atmospheric model forced with a fossil fuel emissions data product. These findings suggest potential for water vapor isotope ratio measurements to be used in conjunction with other tracers to refine the apportionment of urban emissions, and imply that water vapor emissions associated with combustion may be a significant component of the water budget of the urban boundary layer, with potential implications for urban climate, ecohydrology, and photochemistry.« less

Source apportionment and water solubility of metals in size segregated particles in urban environments.

PubMed

Jiang, Sabrina Yanan; Kaul, Daya S; Yang, Fenhuan; Sun, Li; Ning, Zhi

2015-11-15

Metals in atmospheric particulate matter (PM) have been associated with various adverse health effects. Different factors contributing to the characterization and distribution of atmospheric metals in urban environments lead to uncertainty of the understanding of their impact on public health. However, few studies have provided a comprehensive picture of the spatial and seasonal variability of metal concentration, solubility and size distribution, all of which have important roles in their contribution to health effects. This study presents an experimental investigation on the characteristics of metals in PM2.5 and coarse PM in two seasons from four urban sites in Hong Kong. The PM samples were extracted separately with aqua regia and water, and a total of sixteen elements were analyzed using ICP-MS and ICP-OES to determine the size segregated concentration and solubility of metals. The concentrations of major metals were distributed in similar patterns with the same order of magnitude among different urban sites. Source apportionment using Positive Matrix Factorization (PMF) indicated that three sources namely road dust, vehicular exhaust and ship emission are major contributors to the urban atmospheric metal concentrations in Hong Kong with distinctly different profiles between coarse PM and PM2.5 fractions. The individual metals were assigned to different sources, consistent with literature documentation, except potassium emerging with substantial contribution from vehicle exhaust emission. Literature data from past studies on both local and other cities were compared to the results from the present study to investigate the impact of different emission sources and control policies on metal distribution in urban atmosphere. A large variation of solubility among the metals reflected that the majority of metals in PM2.5 were more soluble than those in coarse PM indicating size dependent chemical states of metals. The data from this study provides a rich dataset of metals in urban atmosphere and can be useful for targeted emission control to mitigate the adverse impact of metallic pollution on public health. Copyright © 2015 Elsevier B.V. All rights reserved.

IMPLEMENTATION OF AN URBAN CANOPY PARAMETERIZATION IN MM5

EPA Science Inventory

The Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model (MM5) (Grell et al. 1994) has been modified to include an urban canopy parameterization (UCP) for fine-scale urban simulations (~1-km horizontal grid spacing). The UCP accounts for drag ...

Observing Human-induced Linkages between Urbanization and Earth's Climate System

NASA Technical Reports Server (NTRS)

Shepherd, J. Marshall; Jin, Menglin

2004-01-01

Urbanization is one of the extreme cases of land use change. Most of world s population has moved to urban areas. Although currently only 1.2% of the land is considered urban, the spatial coverage and density of cities are expected to rapidly increase in the near future. It is estimated that by the year 2025, 60% of the world s population will live in cities. Human activity in urban environments also alters atmospheric composition; impacts components of the water cycle; and modifies the carbon cycle and ecosystems. However, our understanding of urbanization on the total Earth-climate system is incomplete. Better understanding of how the Earth s atmosphere-ocean-land-biosphere components interact as a coupled system and the influence of the urban environment on this climate system is critical. The goal of the 2003 AGU Union session Human-induced climate variations on urban areas: From observations to modeling was to bring together scientists from interdisciplinary backgrounds to discuss the data, scientific approaches and recent results on observing and modeling components of the urban environment with the intent of sampling our current stand and discussing future direction on this topic. Herein, a summary and discussion of the observations component of the session are presented.

Exploring Relationships between North American Urban Form and Rates of Urban CO2 Emissions: A System Dynamics Approach

NASA Astrophysics Data System (ADS)

Emmi, P. C.; Forster, C. B.; Mills, J. I.; Call, B. D.; Sabula, J.; Klewicki, J. C.; Pataki, D. E.; Peterson, T. R.

2004-12-01

Cities are the locus of North America's most intense consumption of fossil fuels. Thus the rate and character of urbanization influence the rate of urban CO2 released into the global atmosphere. The rate of rural-to-urban land conversion, and changes in the population density of urban land, are influenced by coupled changes in urban demographics and the local economy. Urban sprawl (a rapid expansion of urban land with low population densities) is governed by a self-reinforcing feedback effect between urban transportation infrastructure investments (road building) and urban land development where road building begets new urban neighborhoods that, in turn, induce more road building that begets additional new neighborhoods. If unrestrained, this feedback effect leads to the unrestrained expansion of urban sprawl, urban vehicular travel and traffic congestion. This self-reinforcing feedback loop forms a key dynamic that controls the rate at which CO2-emitting fossil fuels are burned for transportation, electricity production, heating, and commercial/industrial processes. In a rapidly sprawling city residents must travel increasingly greater distances between work, shopping, and home while commercial service vehicles must travel to increasingly remote residential locations. The increasing number of vehicle trips and vehicle miles traveled, combined with the growing prevalence of ever-lower density urban land development, leads to a rapid increase in mobile and stationary CO2 emissions. A more compact and punctuated form of urban development with higher-density and mixed-use urban activity centers leads to reduced CO2 emissions. Those who shape urban development policy are often unconcerned by increasing CO2 emissions unless they can be linked to: (1) local concerns about criteria air pollutant emissions and air quality, (2) the dependency of federal infrastructure funding on meeting ambient air quality standards, and (3) the consequences of human exposure to health risks associated with declining air quality. The dynamic simulation of urban systems demonstrates that a suite of policies can be found to diminish sprawl and defeat traffic congestion thereby safeguarding the vitality a city. A systems thinking approach, facilitated by a community engagement process, has further enabled community opinion leaders and policy makers to map the key features, linkages and feedbacks of a complex, CO2-emitting urban ecosystem. A corresponding lumped-parameter, simulation model provides a framework for decision makers and stakeholders to explore the consequences of alternative options for managing urban growth, sprawl and congestion while also reducing CO2 emissions.

Correlation between air pollution and weather data in urban areas: Assessment of the city of Rome (Italy) as spatially and temporally independent regarding pollutants

NASA Astrophysics Data System (ADS)

Battista, Gabriele; de Lieto Vollaro, Roberto

2017-09-01

Air pollution represents the biggest environmental risk for health. It is so widespread and it represents one of the main problems of the worldwide, especially because it is emitted by so many different types of sources. The pollutants can originate directly by exhausted or they can be formed because of the reaction with the atmosphere. The first one includes particulate matter and gaseous pollutants such as sulfur oxides, nitrogen oxides, and carbon oxides. The second one includes the ozone formed from nitrogen oxides and hydrocarbons, and particulate sulfate and nitrate aerosols created in the atmosphere from sulfur and nitrogen oxide gases. During the entire life course, people are exposed to the pollutants and suffer from different consequences depending on the age. The first nine month of life are generally recognized as more critical than latter time periods. The mortality associated to air pollutant exposure is main related to the concentrations of NOx , ozone, carbon monoxide, sulfur dioxides and particular matter. More than 92% of the world's population lives in places where air quality levels exceed the standards. In 2012, one out of every nine deaths was the result of air pollution-related conditions. In 2016 about 3 million deaths a year were linked to exposure to outdoor air pollution. In the last few years many epidemiological studies have shown associations between air pollutant concentrations and human health. Apart from people, even monuments and artworks can be damaged by pollution, especially in city centres. Furthermore, urbanization modified microclimate conditions of the cities, and, together with traffic and domestic heating, led to a discomfort of living conditions. For these reasons, there is the necessity to improve the research on the impact of pollutant and microclimate conditions inside urban areas. In this work different kinds of pollutants in Rome from 2006 to 2015 were analysed, and different techniques of post elaboration were used. In particular, the attention was focused on statistic and cross statistic techniques in time and space. The results led to describe Rome as spatially and temporally independence regarding pollutant. Even weather changes were studied in relation with pollution. In particular, cross-correlation analysis were done with air temperature, solar radiation, wind direction and velocity, highlighting a strong coupling for the most of cases except for particular matter.

Long-term urban carbon dioxide observations reveal spatial and temporal dynamics related to urban characteristics and growth

DOE PAGES

Mitchell, Logan E.; Lin, John C.; Bowling, David R.; ...

2018-03-05

Cities are concentrated areas of CO 2 emissions and have become the foci of policies for mitigation actions. However, atmospheric measurement networks suitable for evaluating urban emissions over time are scarce. Here we present a unique long-term (decadal) record of CO 2 mole fractions from five sites across Utah’s metropolitan Salt Lake Valley. We examine “excess” CO 2 above background conditions resulting from local emissions and meteorological conditions. We ascribe CO 2 trends to changes in emissions, since we did not find longterm trends in atmospheric mixing proxies. Three contrasting CO 2 trends emerged across urban types: negative trends atmore » a residentialindustrial site, positive trends at a site surrounded by rapid suburban growth, and relatively constant CO 2 over time at multiple sites in the established, residential, and commercial urban core. Analysis of populationwithin the atmospheric footprints of the different sites reveals approximately equal increases in population influencing the observed CO 2, implying a nonlinear relationshipwith CO 2 emissions: Population growth in rural areas that experienced suburban development was associated with increasing emissions while population growth in the developed urban core was associated with stable emissions. Four state-of-the-art global-scale emission inventories also have a nonlinear relationship with population density across the city; however, in contrast to our observations, they all have nearly constant emissions over time. Our results indicate that decadal scale changes in urban CO 2 emissions are detectable through monitoring networks and constitute a valuable approach to evaluate emission inventories and studies of urban carbon cycles.« less

Long-term urban carbon dioxide observations reveal spatial and temporal dynamics related to urban characteristics and growth

NASA Astrophysics Data System (ADS)

Mitchell, Logan E.; Lin, John C.; Bowling, David R.; Pataki, Diane E.; Strong, Courtenay; Schauer, Andrew J.; Bares, Ryan; Bush, Susan E.; Stephens, Britton B.; Mendoza, Daniel; Mallia, Derek; Holland, Lacey; Gurney, Kevin R.; Ehleringer, James R.

2018-03-01

Cities are concentrated areas of CO2 emissions and have become the foci of policies for mitigation actions. However, atmospheric measurement networks suitable for evaluating urban emissions over time are scarce. Here we present a unique long-term (decadal) record of CO2 mole fractions from five sites across Utah’s metropolitan Salt Lake Valley. We examine “excess” CO2 above background conditions resulting from local emissions and meteorological conditions. We ascribe CO2 trends to changes in emissions, since we did not find long-term trends in atmospheric mixing proxies. Three contrasting CO2 trends emerged across urban types: negative trends at a residential-industrial site, positive trends at a site surrounded by rapid suburban growth, and relatively constant CO2 over time at multiple sites in the established, residential, and commercial urban core. Analysis of population within the atmospheric footprints of the different sites reveals approximately equal increases in population influencing the observed CO2, implying a nonlinear relationship with CO2 emissions: Population growth in rural areas that experienced suburban development was associated with increasing emissions while population growth in the developed urban core was associated with stable emissions. Four state-of-the-art global-scale emission inventories also have a nonlinear relationship with population density across the city; however, in contrast to our observations, they all have nearly constant emissions over time. Our results indicate that decadal scale changes in urban CO2 emissions are detectable through monitoring networks and constitute a valuable approach to evaluate emission inventories and studies of urban carbon cycles.

Long-term urban carbon dioxide observations reveal spatial and temporal dynamics related to urban characteristics and growth

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

Mitchell, Logan E.; Lin, John C.; Bowling, David R.

Cities are concentrated areas of CO 2 emissions and have become the foci of policies for mitigation actions. However, atmospheric measurement networks suitable for evaluating urban emissions over time are scarce. Here we present a unique long-term (decadal) record of CO 2 mole fractions from five sites across Utah’s metropolitan Salt Lake Valley. We examine “excess” CO 2 above background conditions resulting from local emissions and meteorological conditions. We ascribe CO 2 trends to changes in emissions, since we did not find longterm trends in atmospheric mixing proxies. Three contrasting CO 2 trends emerged across urban types: negative trends atmore » a residentialindustrial site, positive trends at a site surrounded by rapid suburban growth, and relatively constant CO 2 over time at multiple sites in the established, residential, and commercial urban core. Analysis of populationwithin the atmospheric footprints of the different sites reveals approximately equal increases in population influencing the observed CO 2, implying a nonlinear relationshipwith CO 2 emissions: Population growth in rural areas that experienced suburban development was associated with increasing emissions while population growth in the developed urban core was associated with stable emissions. Four state-of-the-art global-scale emission inventories also have a nonlinear relationship with population density across the city; however, in contrast to our observations, they all have nearly constant emissions over time. Our results indicate that decadal scale changes in urban CO 2 emissions are detectable through monitoring networks and constitute a valuable approach to evaluate emission inventories and studies of urban carbon cycles.« less

Triple oxygen isotopes indicate urbanization affects sources of nitrate in wet and dry atmospheric deposition

NASA Astrophysics Data System (ADS)

Nelson, David M.; Tsunogai, Urumu; Ding, Dong; Ohyama, Takuya; Komatsu, Daisuke D.; Nakagawa, Fumiko; Noguchi, Izumi; Yamaguchi, Takashi

2018-05-01

Atmospheric nitrate deposition resulting from anthropogenic activities negatively affects human and environmental health. Identifying deposited nitrate that is produced locally vs. that originating from long-distance transport would help inform efforts to mitigate such impacts. However, distinguishing the relative transport distances of atmospheric nitrate in urban areas remains a major challenge since it may be produced locally and/or be transported from upwind regions. To address this uncertainty we assessed spatiotemporal variation in monthly weighted-average Δ17O and δ15N values of wet and dry nitrate deposition during one year at urban and rural sites along the western coast of the northern Japanese island of Hokkaido, downwind of the East Asian continent. Δ17O values of nitrate in wet deposition at the urban site mirrored those of wet and dry deposition at the rural site, ranging between ˜ +23 and +31 ‰ with higher values during winter and lower values in summer, which suggests the greater relative importance of oxidation of NO2 by O3 during winter and OH during summer. In contrast, Δ17O values of nitrate in dry deposition at the urban site were lower (+19 - +25 ‰) and displayed less distinct seasonal variation. Furthermore, the difference between δ15N values of nitrate in wet and dry nitrate deposition was, on average, 3 ‰ greater at the urban than rural site, and Δ17O and δ15N values were correlated for both forms of deposition at both sites with the exception of dry deposition at the urban site. These results suggest that, relative to nitrate in wet and dry deposition in rural environments and wet deposition in urban environments, nitrate in dry deposition in urban environments forms from relatively greater oxidation of NO by peroxy radicals and/or oxidation of NO2 by OH. Given greater concentrations of peroxy radicals and OH in cities, these results imply that dry nitrate deposition results from local NOx emissions more so than wet deposition, which is transported longer distances. These results illustrate the value of stable isotope data for distinguishing the transport distances and reaction pathways of atmospheric nitrate pollution.

Relationship between LINE-1 methylation pattern and pesticide exposure in urban sprayers.

PubMed

Benitez-Trinidad, Alma Betsaida; Medina-Díaz, Irma Martha; Bernal-Hernández, Yael Yvette; Barrón-Vivanco, Briscia Socorro; González-Arias, Cyndia Azucena; Herrera-Moreno, José Francisco; Alvarado-Cruz, Isabel; Quintanilla-Vega, Betzabet; Rojas-García, Aurora Elizabeth

2018-03-01

Recently a relationship has been reported between pesticide exposure and changes in global DNA methylation patterns. Urban sprayers are a particularly vulnerable population because of the high risk of pesticide exposure that their work implies. Therefore, the aim of this study was to estimate the changes in the Long Interspersed Nucleotide Element (LINE-1) in urban sprayers and its relationship with pesticide exposure. The study population consisted of 190 individuals stratified into three study groups: no occupational pesticide exposure; moderate exposure, and high exposure. Pesticide exposure and other external factors such as diet, lifestyle, and others were evaluated through a validated questionnaire, and the butyrylcholinesterase enzyme activity was evaluated spectrophotometrically and used as exposure biomarker. DNA methylation was evaluated by pyrosequencing on bisulfite-treated DNA. The results showed a significant decrease of %5mC in both the moderate- and high-exposure groups with respect to the non-exposed group (p < 0.05). In addition, alcohol intake was associated with a higher percentage of LINE- 1 methylation. In conclusion, our results suggest that occupational pesticide exposure and external factors appears to modify the DNA methylation pattern measured through LINE-1. Copyright © 2018 Elsevier Ltd. All rights reserved.

Landscapes of thermal inequity: disproportionate exposure to urban heat in the three largest US cities

NASA Astrophysics Data System (ADS)

Mitchell, Bruce C.; Chakraborty, Jayajit

2015-11-01

Heat waves are the most significant cause of mortality in the US compared to other natural hazards. Prior studies have found increased heat exposure for individuals of lower socioeconomic status in several US cities, but few comparative analyses of the social distribution of urban heat have been conducted. To address this gap, our paper examines and compares the environmental justice consequences of urban heat risk in the three largest US cities: New York City, Los Angeles, and Chicago. Risk to urban heat is estimated on the basis of three characteristics of the urban thermal landscape: land surface temperature, vegetation abundance, and structural density of the built urban environment. These variables are combined to develop an urban heat risk index, which is then statistically compared with social vulnerability indicators representing socioeconomic status, age, disability, race/ethnicity, and linguistic isolation. The results indicate a consistent and significant statistical association between lower socioeconomic and minority status and greater urban heat risk, in all three cities. Our findings support a growing body of environmental justice literature that indicates the presence of a landscape of thermal inequity in US cities and underscores the need to conduct comparative analyses of social inequities in exposure to urban heat.

Exposure to Violence and Sexual Risk among Early Adolescents in Urban Middle Schools

ERIC Educational Resources Information Center

Coyle, Karin K.; Guinosso, Stephanie A.; Glassman, Jill R.; Anderson, Pamela M.; Wilson, Helen W.

2017-01-01

This article examines the relationship between exposure to violence, fear of exposure to violence, and sexual risk among a sample of urban middle school youth. The sample included 911 seventh-grade students who completed self-report surveys. Approximately 20% of the sample reported at least one direct threat or injury with a weapon in the past 3…

Outside and inside noise exposure in urban and suburban areas

Treesearch

Dwight E. Bishop; Myles A. Simpson

1977-01-01

In urban and suburban areas of the United States (away from major airports), the outdoor noise environment usually depends strongly on local vehicular traffic. By relating traffic flow to population density, a model of outdoor noise exposure has been developed for estimating the cumulative 24-hour noise exposure based upon the population density of the area. This noise...

Atmospheric pollutants in peri-urban forests of Quercus ilex: evidence of pollution abatement and threats for vegetation.

PubMed

García-Gómez, Héctor; Aguillaume, Laura; Izquieta-Rojano, Sheila; Valiño, Fernando; Àvila, Anna; Elustondo, David; Santamaría, Jesús M; Alastuey, Andrés; Calvete-Sogo, Héctor; González-Fernández, Ignacio; Alonso, Rocío

2016-04-01

Peri-urban vegetation is generally accepted as a significant remover of atmospheric pollutants, but it could also be threatened by these compounds, with origin in both urban and non-urban areas. To characterize the seasonal and geographical variation of pollutant concentrations and to improve the empirical understanding of the influence of Mediterranean broadleaf evergreen forests on air quality, four forests of Quercus ilex (three peri-urban and one remote) were monitored in different areas in Spain. Concentrations of nitrogen dioxide (NO2), ammonia (NH3), nitric acid (HNO3) and ozone (O3) were measured during 2 years in open areas and inside the forests and aerosols (PM10) were monitored in open areas during 1 year. Ozone was the only air pollutant expected to have direct phytotoxic effects on vegetation according to current thresholds for the protection of vegetation. The concentrations of N compounds were not high enough to directly affect vegetation but could be contributing through atmospheric N deposition to the eutrophization of these ecosystems. Peri-urban forests of Q. ilex showed a significant below-canopy reduction of gaseous concentrations (particularly NH3, with a mean reduction of 29-38%), which indicated the feasibility of these forests to provide an ecosystem service of air quality improvement. Well-designed monitoring programs are needed to further investigate air quality improvement by peri-urban ecosystems while assessing the threat that air pollution can pose to vegetation.

Multi-Scale Enviro-HIRLAM Forecasting of Weather and Atmospheric Composition over China and its Megacities

NASA Astrophysics Data System (ADS)

Mahura, Alexander; Amstrup, Bjarne; Nuterman, Roman; Yang, Xiaohua; Baklanov, Alexander

2017-04-01

Air pollution is a serious problem in different regions of China and its continuously growing megacities. Information on air quality, and especially, in urbanized areas is important for decision making, emergency response and population. In particular, the metropolitan areas of Shanghai, Beijing, and Pearl River Delta are well known as main regions having serious air pollution problems. The on-line integrated meteorology-chemistry-aerosols Enviro-HIRLAM (Environment - HIgh Resolution Limited Area Model) model adapted for China and selected megacities is applied for forecasting of weather and atmospheric composition (with focus on aerosols). The model system is running in downscaling chain from regional to urban scales at subsequent horizontal resolutions of 15-5-2.5 km. The model setup includes also the urban Building Effects Parameterization module, describing different types of urban districts (industrial commercial, city center, high density and residential) with its own morphological and aerodynamical characteristics. The effects of urbanization are important for atmospheric transport, dispersion, deposition, and chemical transformations, in addition to better quality emission inventories for China and selected urban areas. The Enviro-HIRLAM system provides meteorology and air quality forecasts at regional-subregional-urban scales (China - East China - selected megacities). In particular, such forecasting is important for metropolitan areas, where formation and development of meteorological and chemical/aerosol patterns are especially complex. It also provides information for evaluation impact on selected megacities of China as well as for investigation relationship between air pollution and meteorology.

No evidence for an effect of traffic noise on the development of the corticosterone stress response in an urban exploiter.

PubMed

Angelier, Frédéric; Meillère, Alizée; Grace, Jacquelyn K; Trouvé, Colette; Brischoux, François

2016-06-01

Anthropogenic noise can have important physiological and behavioral effects on wild animals. For example, urban noise could lead to a state of chronic stress and could alter the development of the hypothalamus-pituitary-adrenal (HPA) axis. Supporting this hypothesis, several studies have found that human disturbance is associated with increased circulating corticosterone (CORT) levels. However, it remains unclear whether increased CORT levels are the result of anthropogenic noise or other anthropogenic factors. Here, we experimentally tested the impact of urban noise on the CORT stress response in an urban exploiter (the house sparrow, Passer domesticus) by exposing chicks to a traffic noise ('disturbed chicks') or not ('control chicks'). If noise exposure has a negative impact on developing chicks, we predicted that (1) disturbed chicks will grow slower, will be in poorer condition, and will have a lower fledging probability than controls; (2) disturbed chicks will have higher baseline CORT levels than control; (3) the CORT stress response will be affected by this noise exposure. Contrary to these predictions, we found no effect of our experiment on growth, body condition, and fledging success, suggesting that house sparrow chicks were not negatively affected by this noise exposure. Moreover, we did not find any effect of noise exposure on either baseline CORT levels or the CORT stress response of chicks. This suggests not only that house sparrow chicks did not perceive this noise as stressful, but also that the development of the HPA axis was not affected by such noise exposure. Our study suggests that, contrary to urban avoiders, urban exploiters might be relatively insensitive to urban noise during their development. Further comparative studies are now needed to understand whether such insensitivity to anthropogenic noise is a consistent phenomenon in urban exploiters and whether this is a major requirement of an urban way of life. Copyright © 2015 Elsevier Inc. All rights reserved.

Local-Rapid Evaluation of Atmospheric Conditions (L-REAC)

DTIC Science & Technology

2009-01-15

installation available 24/7 to all forms of browser-based access such as mobile blackberry browser. In 2006, the ARL presented data at an International...Oceanic and Atmospheric Administration (NOAA)/Environmental Protection Agency (EPA) Wind Tunnel study with tens-of-meter-scaled measurements sampled around...urban flow in wind tunnels , as well as articles from professional urban meteorological journals. The need to maintain a visual sensor for persons who

Using an epiphytic moss to identify previously unknown sources of atmospheric cadmium pollution

Treesearch

Geoffrey H. Donovan; Sarah E. Jovan; Demetrios Gatziolis; Igor Burstyn; Yvonne L. Michael; Michael C. Amacher; Vicente J. Monleon

2016-01-01

Urban networks of air-quality monitors are often too widely spaced to identify sources of air pollutants, especially if they do not disperse far from emission sources. The objectives of this study were to test the use of moss bio-indicators to develop a fine-scale map of atmospherically-derived cadmium and to identify the sources of cadmium in a complex urban setting....

Photochemistry in the Atmospheres of Denver and Mexico City

NASA Astrophysics Data System (ADS)

Cantrell, C. A.

2016-12-01

The composition of atmospheres in and downwind of urban centers has been the subject of study for decades. While early campaigns involved measurements exclusively from the ground, more recent studies have included airborne-based observations. Improved understanding has hinged critically on the development of instrumentation for better qualitifcation of pollutants, and measurement of previously unobserved species in the gas and particulate phases. Comprehensive, well-planned studies have, over time, led to more detailed understanding of chemical transformations and thus improved model representations and directions for further research. This presentation focuses on findings from two case studies of urban atmospheres, namely the MILAGRO study in the Mexico City metropolitan area and the FRAPPE study in the Denver metropolitan region. Both studies made use of extensive ground-based networks and multiple aircraft platforms. The data collected during these studies have been combined with numerical models to derive assessments of the evolution of atmospheric composition due to photochemistry, mixing, and surface processes. Here, analysis of MILAGRO data focuses on the evolution of outflow downwind of the urban region. In FRAPPE, the focus is the possible role of oil and gas exploration on urban air quality. These findings are used to assess the accuracy of current numerical models to reproduce observations, and to point toward areas possibly needing further study.

Rapid Removal of Atmospheric CO2 by Urban Soils.

PubMed

Washbourne, Carla-Leanne; Lopez-Capel, Elisa; Renforth, Phil; Ascough, Philippa L; Manning, David A C

2015-05-05

The measured calcium carbonate content of soils to a depth of 100 mm at a large urban development site has increased over 18 months at a rate that corresponds to the sequestration of 85 t of CO2/ha (8.5 kg of CO2 m(-2)) annually. This is a consequence of rapid weathering of calcium silicate and hydroxide minerals derived from the demolition of concrete structures, which releases Ca that combines with CO2 ultimately derived from the atmosphere, precipitating as calcite. Stable isotope data confirm an atmospheric origin for carbonate carbon, and 14C dating indicates the predominance of modern carbon in the pedogenic calcite. Trial pits show that carbonation extends to depths of ≥1 m. Work at other sites shows that the occurrence of pedogenic carbonates is widespread in artificially created urban soils containing Ca and Mg silicate minerals. Appropriate management of fewer than 12000 ha of urban land to maximize calcite precipitation has the potential to remove 1 million t of CO2 from the atmosphere annually. The maximal global potential is estimated to be approximately 700-1200 Mt of CO2 per year (representing 2.0-3.7% of total emissions from fossil fuel combustion) based on current rates of production of industry-derived Ca- and Mg-bearing materials.

Personal inhalation exposure to polycyclic aromatic hydrocarbons in urban and rural residents in a typical northern city in China.

PubMed

Duan, X; Wang, B; Zhao, X; Shen, G; Xia, Z; Huang, N; Jiang, Q; Lu, B; Xu, D; Fang, J; Tao, S

2014-10-01

Personal inhalation exposure samples were collected and analyzed for polycyclic aromatic hydrocarbons (PAHs) for 126 selected volunteers during heating and non-heating seasons in a typical northern Chinese city, Taiyuan. Measured personal PAH exposure levels for the urban residents in the heating and non-heating seasons were 690 (540-1051) and 404 (266-544) ng/m(3) , respectively, while, for the rural residents, they were 770 (504-1071) and 312 (201-412) ng/m(3) , respectively. Thus, rural residents are exposed to lower PAH contamination in comparison with the urban residents in the non-heating seasons. In the heating season, personal PAH inhalation exposure levels were comparable between the urban and rural residents, in part owing to the large rate of residential solid fuel consumption in the rural area for household cooking and heating. The estimated incremental lifetime cancer risks (ILCR) due to PAH exposure in Taiyuan were 3.36 × 10(-5) and 2.39 × 10(-5) for the rural and urban residents, respectively, significantly higher than the literature-reported national average level, suggesting an urgent need of PAH pollution control to protect human health. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Exposure to Community Violence and the Trajectory of Internalizing and Externalizing Symptoms in a Sample of Low-Income Urban Youth.

PubMed

Taylor, Jeremy J; Grant, Kathryn E; Zulauf, Courtney A; Fowler, Patrick J; Meyerson, David A; Irsheid, Sireen

2018-01-01

This study examined trajectories of psychopathology in a sample of low-income urban youth and tested exposure to community violence as a predictor of these trajectories. Self-report and parent-report survey measures of psychological problems and exposure to community violence were collected annually over 3 years from a sample of 364 fifth- to ninth-grade low-income urban youth (64% female; 95% youth of color). Linear growth models showed that youth experienced declines in both internalizing and externalizing symptoms across adolescence. Exposure to community violence was more strongly associated with externalizing symptoms than with internalizing symptoms but predicted declines in both types of symptoms. Results also indicated that youth reported more internalizing and externalizing symptoms than their parents reported for them. Exposure to community violence may explain unique trajectories of mental health problems among low-income urban youth. In addition, youth efforts to adopt a tough façade in the face of community violence could lead to higher rates of externalizing problems relative to internalizing problems, whereas desensitization processes may better explain reductions in both types of symptoms over time. Finally, youth report may be more valid than parent report in the context of urban poverty.

A multi-residue method for characterization and determination of atmospheric pesticides measured at two French urban and rural sampling sites.

PubMed

Baraud, Laurent; Tessier, Didier; Aaron, Jean-Jacques; Quisefit, Jean-Paul; Pinart, Johann

2003-12-01

The extensive use of pesticides to protect agricultural crops can result in the transfer of these compounds into the atmosphere and their diffusion towards urban areas. Precise evaluation of the geographic impact of this type of pollution is important environmentally. In this paper, analytical methods for the sampling, characterization, and determination of agricultural pesticides in air were developed; the methods were then applied in the Paris and Champagne regions. Sixteen pesticides belonging to nine chemical families were monitored. Sampling was carried out in urban (Paris) and rural (Aube district) sites, utilizing either a high-volume pump (12.5 m3 h(-1)) (urban site) or a low-volume pump (2.3 m3 h(-1)) for the rural site. Quartz filters and polyurethane foams (PUF) were used for sampling in all cases. After extracting the samples and concentrating the recovered solutions, high-performance liquid chromatography (HPLC) analysis with UV detection was performed. Identification of the pesticides was confirmed by applying to the HPLC measurements a novel UV-detection procedure based on the normalized absorbance variation with wavelength (Noravawa procedure). The presence of metsulfuron methyl, isoproturon, linuron, deltamethrin (and/or malathion), and chlorophenoxy acids (2,4-D and MCPP) was found at the urban sampling site at levels ranging from about 1 to 1130 ng m(-3) of air, depending on the compound and sampling period. On the rural sampling site residues of isoproturon, deltamethrin (and/or malathion), MCPP, and 2,4-D were generally detected at higher levels (19-5130 ng m(-3)) than on the urban site, as expected. The effects of the weather conditions and agricultural activity on the atmospheric concentrations of pesticides are discussed, as are long-range atmospheric transfer processes for these pesticides.

The Integrated WRF/Urban Modeling System: Development, Evaluation, and Applications to Urban Environmental Problems

EPA Science Inventory

To bridge the gaps between traditional mesoscale modelling and microscale modelling, the National Center for Atmospheric Research, in collaboration with other agencies and research groups, has developed an integrated urban modelling system coupled to the weather research and fore...

IMPLEMENTATION OF AN URBAN CANOPY PARAMETERIZATION FOR FINE-SCALE SIMULATIONS

EPA Science Inventory

The Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model (MM5) (Grell et al. 1994) has been modified to include an urban canopy parameterization (UCP) for fine-scale urban simulations ( 1 - km horizontal grid spacing ). The UCP accounts for dr...

The effect of atmospheric thermal conditions and urban thermal pollution on all-cause and cardiovascular mortality in Bangladesh.

PubMed

Burkart, Katrin; Schneider, Alexandra; Breitner, Susanne; Khan, Mobarak Hossain; Krämer, Alexander; Endlicher, Wilfried

2011-01-01

This study assessed the effect of temperature and thermal atmospheric conditions on all-cause and cardiovascular mortality in Bangladesh. In particular, differences in the response to elevated temperatures between urban and rural areas were investigated. Generalized additive models (GAMs) for daily death counts, adjusted for trend, season, day of the month and age were separately fitted for urban and rural areas. Breakpoint models were applied for determining the increase in mortality above and below a threshold (equivalent) temperature. Generally, a 'V'-shaped (equivalent) temperature-mortality curve with increasing mortality at low and high temperatures was observed. Particularly, urban areas suffered from heat-related mortality with a steep increase above a specific threshold. This adverse heat effect may well increase with ongoing urbanization and the intensification of the urban heat island due to the densification of building structures. Moreover, rising temperatures due to climate change could aggravate thermal stress. Copyright © 2011 Elsevier Ltd. All rights reserved.

Rural–urban differences in exposure to adverse childhood experiences among South Carolina adults.

PubMed

Radcliff, Elizabeth; Crouch, Elizabeth; Strompolis, Melissa

2018-02-01

Adverse childhood experiences (ACEs) are traumatic events that occur in a child's life between birth and 18 years. Exposure to one or more ACE has been linked to participation in risky health behaviors and the experience of chronic health conditions in adulthood. The risk for poor outcomes increases as the number of ACEs experienced increases. This research investigates rural-urban differences in exposure to ACEs using a sample from a representative southern US state, South Carolina. Using data from the 2014-2015 South Carolina Behavioral Risk Factor Surveillance System (BRFSS) and residential rurality based on UICs, ACE exposure among South Carolina adults was tabulated by urban versus rural residence and selected other demographic characteristics. Using standard descriptive statistics, frequencies and proportions were calculated for each categorical variable. Multivariable regression modeling was used to examine the impact of residential rurality and selected sociodemographic characteristics on overall and specific types of ACE exposure. All analyses used survey sampling weights that accounted for the BRFSS sampling strategy. The analytic sample of 18 176 respondents comprised 15.9% rural residents. Top reported ACEs for both rural and urban residents were the same: parental divorce/separation, emotional abuse, and household substance use. Compared to urban residents, a higher proportion of rural respondents reported experiencing no ACEs (41.4% vs 38.3%, p<0.01). The prevalence of four or more ACEs in rural respondents was 15.0%; in comparison, 17.6% of urban respondents had four or more ACEs (p<0.01). In logistic regression predicting exposure to four or more ACEs and adjusting for sex, age, race/ethnicity, education, and income, rural respondents were less likely than urban respondents to report four or more ACEs (adjusted odds ratio 0.75, 95% confidence interval 0.74-0.75). Despite reporting less ACE exposure than urban counterparts, almost 60% of rural residents reported at least one ACE and 15% reported experiencing four or more ACEs. In contrast to urban residents, rural residents may experience more social connections within their families and communities, which may influence ACE exposure; however, care coordination, social support services, and access to health care are limited in rural areas. Thus, families in rural areas may be less equipped to mitigate and manage the effects of ACEs. Findings from this study thus suggest that interventions to prevent ACE exposure are just as needed in rural southern communities as they are in urban southern communities. Topics important for future research could include an examination of ACEs in rural communities in terms of individuals' health outcomes and their access to health care, as well as the role of protective factors. Programs and policies that assist in ACE prevention in rural areas are important to reducing these multigenerational threats to health and wellbeing.

Effect of Exposure to Atmospheric Ultrafine Particles on Production of Free Fatty Acids and Lipid Metabolites in the Mouse Small Intestine

PubMed Central

Li, Rongsong; Navab, Kaveh; Hough, Greg; Daher, Nancy; Zhang, Min; Mittelstein, David; Lee, Katherine; Pakbin, Payam; Saffari, Arian; Bhetraratana, May; Sulaiman, Dawoud; Beebe, Tyler; Wu, Lan; Jen, Nelson; Wine, Eytan; Tseng, Chi-Hong; Araujo, Jesus A.; Fogelman, Alan; Sioutas, Constantinos; Navab, Mohamed

2014-01-01

Background: Exposure to ambient ultrafine particulate matter (UFP) is a well-recognized risk factor for cardiovascular and respiratory diseases. However, little is known about the effects of air pollution on gastrointestinal disorders. Objective: We sought to assess whether exposure to ambient UFP (diameter < 180 nm) increased free fatty acids and lipid metabolites in the mouse small intestine. Methods: Ldlr-null mice were exposed to filtered air (FA) or UFP collected at an urban Los Angeles, California, site that was heavily affected by vehicular emissions; the exposure was carried out for 10 weeks in the presence or absence of D-4F, an apolipoprotein A-I mimetic peptide with antioxidant and anti-inflammation properties on a high-fat or normal chow diet. Results: Compared with FA, exposure to UFP significantly increased intestinal hydroxyeicosatetraenoic acids (HETEs), including 15-HETE, 12-HETE, 5-HETE, as well as hydroxyoctadecadienoic acids (HODEs), including 13-HODE and 9-HODE. Arachidonic acid (AA) and prostaglandin D2 (PGD2) as well as some of the lysophosphatidic acids (LPA) in the small intestine were also increased in response to UFP exposure. Administration of D-4F significantly reduced UFP-mediated increase in HETEs, HODEs, AA, PGD2, and LPA. Although exposure to UFP further led to shortened villus length accompanied by prominent macrophage and neutrophil infiltration into the intestinal villi, administration of D-4F mitigated macrophage infiltration. Conclusions: Exposure to UFP promotes lipid metabolism, villus shortening, and inflammatory responses in mouse small intestine, whereas administration of D-4F attenuated these effects. Our findings provide a basis to further assess the mechanisms underlying UFP-mediated lipid metabolism in the digestive system with clinical relevance to gut homeostasis and diseases. Citation: Li R, Navab K, Hough G, Daher N, Zhang M, Mittelstein D, Lee K, Pakbin P, Saffari A, Bhetraratana M, Sulaiman D, Beebe T, Wu L, Jen N, Wine E, Tseng CH, Araujo JA, Fogelman A, Sioutas C, Navab M, Hsiai TK. 2015. Effect of exposure to atmospheric ultrafine particles on production of free fatty acids and lipid metabolites in the mouse small intestine. Environ Health Perspect 123:34–41; http://dx.doi.org/10.1289/ehp.1307036 PMID:25170928

Informing urban carbon emissions with atmospheric observations: motivation, methods, and reducing uncertainties.

NASA Astrophysics Data System (ADS)

Kort, E. A.; Ware, J.; Duren, R. M.; Schimel, D.; Miller, C. E.; Decola, P.

2014-12-01

Urban regions play a dominant role in the anthropogenic perturbation to atmospheric carbon dioxide and methane. With increasing urbanization (notably in developing nations) and increasing emissions, quantitative observational information on emissions of CO2 and CH4 becomes critical for improved understanding of the global carbon cycle and for carbon management/policy decisions. In this presentation, we will discuss the impact uncertainty in anthropogenic emissions has on global carbon-climate understanding, providing broad geophysical motivation for urban studies. We will further discuss observations of urban regions at different scales (satellite vs. in-situ), and investigate the information content of these complementary methods for answering targeted questions on both global carbon fluxes and regional management decisions. Finally, we will present new attempts at reducing uncertainty in high-resolution inversions leveraging remotely sensed aerosol profiles to constrain both mixing depths and vertical distributions of trace gases.

Use of GLOBE Observations to Derive a Landsat 8 Split Window Algorithm for Urban Heat Island

NASA Astrophysics Data System (ADS)

Fagerstrom, L.; Czajkowski, K. P.

2017-12-01

Surface temperature has been studied to investigate the warming of urban climates, also known as urban heat islands, which can impact urban planning, public health, pollution levels, and energy consumption. However, the full potential of remotely sensed images is limited when analyzing land surface temperature due to the daunting task of correcting for atmospheric effects. Landsat 8 has two thermal infrared sensors. With two bands in the infrared region, a split window algorithm (SWA), can be applied to correct for atmospheric effects. This project used in situ surface temperature measurements from NASA's ground observation program, the Global Learning and Observations to Benefit the Environment (GLOBE), to derive the correcting coefficients for use in the SWA. The GLOBE database provided land surface temperature data that coincided with Landsat 8 overpasses. The land surface temperature derived from Landsat 8 SWA can be used to analyze for urban heat island effect.

Rural-urban differences in cooking practices and exposures in Northern Ghana

NASA Astrophysics Data System (ADS)

Wiedinmyer, Christine; Dickinson, Katherine; Piedrahita, Ricardo; Kanyomse, Ernest; Coffey, Evan; Hannigan, Michael; Alirigia, Rex; Oduro, Abraham

2017-07-01

Key differences between urban and rural populations can influence the adoption and impacts of new cooking technologies and fuels. We examine these differences among urban and rural households that are part of the REACCTING study in Northern Ghana. While urban and rural populations in the study area all use multiple stoves, the types of stoves and fuels differ, with urban participants more likely to use charcoal and LPG while rural households rely primarily on wood. Further, rural and urban households tend to use different stoves/fuels to cook the same dishes—for example, the staple porridge Tuo Zaafi (TZ) is primarily cooked over wood fires in rural areas and charcoal stoves in urban settings. This suggests that fuel availability and ability to purchase fuel may be a stronger predictor of fuel choice than cultural preferences alone. Ambient concentrations of air pollutants also differ in these two types of areas, with urban areas having pollutant hot spots to which residents can be exposed and rural areas having more homogeneous and lower pollutant concentrations. Further, exposures to carbon monoxide and particulate matter differ in magnitude and in timing between urban and rural study participants, suggesting different behaviors and sources of exposures. The results from this analysis highlight important disparities between urban and rural populations of a single region and imply that such a characterization is needed to successfully implement and assess the impacts of household energy interventions.

Spatial and Temporal Distribution of Current-Use Pesticides in Atmospheric Particulate Matter in Houston, Texas.

PubMed

Clark, Adelaide E; Yoon, Subin; Sheesley, Rebecca J; Usenko, Sascha

2016-12-01

The atmospheric concentrations of seven current-use pesticides in particulate matter were determined at four locations throughout the Houston metropolitan area in TSP and PM 2.5 samples from September 2013. Atmospheric concentrations in both TSP and PM 2.5 ranged from below method detection limits (MDLs) to nearly 1100 pg m -3 . The three compounds most frequently detected above MDLs were chlorothalonil, bifenthrin, and λ-cyhalothrin. Atmospheric chlorothalonil concentrations were above 800 pg m -3 in several TSP samples, but

On the role of hydrophobic Si-based protective coatings in limiting mortar deterioration.

PubMed

Cappelletti, G; Fermo, P; Pino, F; Pargoletti, E; Pecchioni, E; Fratini, F; Ruffolo, S A; La Russa, M F

2015-11-01

In order to avoid both natural and artificial stone decay, mainly due to the interaction with atmospheric pollutants (both gases such as NOx and SO2 and particulate matter), polymeric materials have been widely studied as protective coatings enable to limit the penetration of fluids into the bulk material. In the current work, an air hardening calcic lime mortar (ALM) and a natural hydraulic lime mortar (HLM) were used as substrates, and commercially available Si-based resins (Alpha®SI30 and Silres®BS16) were adopted as protective agents to give hydrophobicity features to the artificial stones. Surface properties of coatings and their performance as hydrophobic agents were studied using different techniques such as contact angle measurements, capillary absorption test, mercury intrusion porosimetry, surface free energy, colorimetric measurements and water vapour permeability tests. Finally, some exposure tests to UV radiation and to real polluted atmospheric environments (a city centre and an urban background site) were carried out during a wintertime period (when the concentrations of the main atmospheric pollutants are higher) in order to study the durability of the coating systems applied. The effectiveness of the two commercial resins in reducing salt formation (sulphate and nitrate), induced by the interaction of the mortars with the atmospheric pollutants, was demonstrated in the case of the HLM mortar. Graphical Abstract ᅟ.

Modeling and evaluation of urban pollution events of atmospheric heavy metals from a large Cu-smelter.

PubMed

Chen, Bing; Stein, Ariel F; Castell, Nuria; Gonzalez-Castanedo, Yolanda; Sanchez de la Campa, A M; de la Rosa, J D

2016-01-01

Metal smelting and processing are highly polluting activities that have a strong influence on the levels of heavy metals in air, soil, and crops. We employ an atmospheric transport and dispersion model to predict the pollution levels originated from the second largest Cu-smelter in Europe. The model predicts that the concentrations of copper (Cu), zinc (Zn), and arsenic (As) in an urban area close to the Cu-smelter can reach 170, 70, and 30 ng m−3, respectively. The model captures all the observed urban pollution events, but the magnitude of the elemental concentrations is predicted to be lower than that of the observed values; ~300, ~500, and ~100 ng m−3 for Cu, Zn, and As, respectively. The comparison between model and observations showed an average correlation coefficient of 0.62 ± 0.13. The simulation shows that the transport of heavy metals reaches a peak in the afternoon over the urban area. The under-prediction in the peak is explained by the simulated stronger winds compared with monitoring data. The stronger simulated winds enhance the transport and dispersion of heavy metals to the regional area, diminishing the impact of pollution events in the urban area. This model, driven by high resolution meteorology (2 km in horizontal), predicts the hourly-interval evolutions of atmospheric heavy metal pollutions in the close by urban area of industrial hotspot.

Metallic corrosion in the polluted urban atmosphere of Hong Kong.

PubMed

Liu, Bo; Wang, Da-Wei; Guo, Hai; Ling, Zhen-Hao; Cheung, Kalam

2015-01-01

This study aimed to explore the relationship between air pollutants, particularly acidic particles, and metallic material corrosion. An atmospheric corrosion test was carried out in spring-summer 2012 at a polluted urban site, i.e., Tung Chung in western Hong Kong. Nine types of metallic materials, namely iron, Q235 steel, 20# steel, 16Mn steel, copper, bronze, brass, aluminum, and aluminum alloy, were selected as specimens for corrosion tests. Ten sets of the nine materials were all exposed to ambient air, and then each set was collected individually after exposure to ambient air for consecutive 6, 13, 20, 27, 35, 42, 49, 56, 63, and 70 days, respectively. After the removal of the corrosion products on the surface of the exposed specimens, the corrosion rate of each material was determined. The surface structure of materials was observed using scanning electron microscopy (SEM) before and after the corrosion tests. Environmental factors including temperature, relative humidity, concentrations of gaseous pollutants, i.e., sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), ozone (O₃), and particulate-phase pollutants, i.e., PM₂.₅ (FSP) and PM₁₀ (RSP), were monitored. Correlation analysis between environmental factors and corrosion rate of materials indicated that iron and carbon steel were damaged by both gaseous pollutants (SO₂ and NO₂) and particles. Copper and copper alloys were mainly corroded by gaseous pollutants (SO₂ and O₃), while corrosion of aluminum and aluminum alloy was mainly attributed to NO₂ and particles.

Leaf enclosure measurement for determining marijuana volatile organic compound emission factors

NASA Astrophysics Data System (ADS)

Wang, C. T.; Vizuete, W.; Wiedinmyer, C.; Ashworth, K.; Harley, P. C.; Ortega, J. V.

2017-12-01

In 2014, Colorado became the first US state to legalize the industrial-scale cultivation of marijuana plants. There are now more than 700 marijuana cultivation facilities (MCFs) in operation in the greater Denver area. High concentrations of biogenic volatile organic compounds (VOCs), predominantly monoterpenes (C10H16) such as alpha-pinene, myrcene, and limonene have been observed in the grow rooms of MCFs, suggesting MCFs have the potential to release a significant amount of reactive VOCs into the atmosphere. Further, many MCFs are located in the urban core, where other urban emission sources are concentrated, resulting in interactions which can lead to the formation of ozone, impacting air quality. The little research done on marijuana has focused on indoor air quality and occupational exposure, or identification of the compounds associated with the characteristic smells of marijuana plants. We know of no previous studies that have identified or quantified the monoterpene emission rates from marijuana. Here, we collected air samples from leaf enclosures from different marijuana clones at different growth stages onto sorbent cartridges. These samples were analyzed using GC-MS/-FID to identify and quantify the VOCs emitted by growing marijuana plants. These results were then used to estimate basal emission rates at standard conditions (T=30 C, PPFD = 1000 umol/m2/s) using standard algorithms. We discuss the potential impact on air quality from these VOCs emitted into the atmosphere using air quality models.

A statistical framework for the validation of a population exposure model based on personal exposure data

NASA Astrophysics Data System (ADS)

Rodriguez, Delphy; Valari, Myrto; Markakis, Konstantinos; Payan, Sébastien

2016-04-01

Currently, ambient pollutant concentrations at monitoring sites are routinely measured by local networks, such as AIRPARIF in Paris, France. Pollutant concentration fields are also simulated with regional-scale chemistry transport models such as CHIMERE (http://www.lmd.polytechnique.fr/chimere) under air-quality forecasting platforms (e.g. Prev'Air http://www.prevair.org) or research projects. These data may be combined with more or less sophisticated techniques to provide a fairly good representation of pollutant concentration spatial gradients over urban areas. Here we focus on human exposure to atmospheric contaminants. Based on census data on population dynamics and demographics, modeled outdoor concentrations and infiltration of outdoor air-pollution indoors we have developed a population exposure model for ozone and PM2.5. A critical challenge in the field of population exposure modeling is model validation since personal exposure data are expensive and therefore, rare. However, recent research has made low cost mobile sensors fairly common and therefore personal exposure data should become more and more accessible. In view of planned cohort field-campaigns where such data will be available over the Paris region, we propose in the present study a statistical framework that makes the comparison between modeled and measured exposures meaningful. Our ultimate goal is to evaluate the exposure model by comparing modeled exposures to monitor data. The scientific question we address here is how to downscale modeled data that are estimated on the county population scale at the individual scale which is appropriate to the available measurements. To assess this question we developed a Bayesian hierarchical framework that assimilates actual individual data into population statistics and updates the probability estimate.

Seasonal and spatial variation of organic tracers for biomass burning in PM1 aerosols from highly insolated urban areas.

PubMed

van Drooge, B L; Fontal, M; Bravo, N; Fernández, P; Fernández, M A; Muñoz-Arnanz, J; Jiménez, B; Grimalt, J O

2014-10-01

PM1 aerosol characterization on organic tracers for biomass burning (levoglucosan and its isomers and dehydroabietic acid) was conducted within the AERTRANS project. PM1 filters (N = 90) were sampled from 2010 to 2012 in busy streets in the urban centre of Madrid and Barcelona (Spain) at ground-level and at roof sites. In both urban areas, biomass burning was not expected to be an important local emission source, but regional emissions from wildfires, residential heating or biomass removal may influence the air quality in the cities. Although both areas are under influence of high solar radiation, Madrid is situated in the centre of the Iberian Peninsula, while Barcelona is located at the Mediterranean Coast and under influence of marine atmospheres. Two extraction methods were applied, i.e. Soxhlet and ASE, which showed equivalent results after GC-MS analyses. The ambient air concentrations of the organic tracers for biomass burning increased by an order of magnitude at both sites during winter compared to summer. An exception was observed during a PM event in summer 2012, when the atmosphere in Barcelona was directly affected by regional wildfire smoke and levels were four times higher as those observed in winter. Overall, there was little variation between the street and roof sites in both cities, suggesting that regional biomass burning sources influence the urban areas after atmospheric transport. Despite the different atmospheric characteristics in terms of air relative humidity, Madrid and Barcelona exhibit very similar composition and concentrations of biomass burning organic tracers. Nevertheless, levoglucosan and its isomers seem to be more suitable for source apportionment purposes than dehydroabietic acid. In both urban areas, biomass burning contributions to PM were generally low (2 %) in summer, except on the day when wildfire smoke arrive to the urban area. In the colder periods the contribution increase to around 30 %, indicating that regional biomass burning has a substantial influence on the urban air quality.

Psychotic disorder and educational achievement: a family-based analysis.

PubMed

Frissen, Aleida; Lieverse, Ritsaert; Marcelis, Machteld; Drukker, Marjan; Delespaul, Philippe

2015-10-01

Early social and cognitive alterations in psychotic disorder, associated with familial liability and environmental exposures, may contribute to lower than expected educational achievement. The aims of the present study were to investigate (1) how differences in educational level between parents and their children vary across patients, their healthy siblings, and healthy controls (effect familial liability), and across two environmental risk factors for psychotic disorder: childhood trauma and childhood urban exposure (effect environment) and (2) to what degree the association between familial liability and educational differential was moderated by the environmental exposures. Patients with a diagnosis of non-affective psychotic disorder (n = 629), 552 non-psychotic siblings and 326 healthy controls from the Netherlands and Belgium were studied. Participants reported their highest level of education and that of their parents. Childhood trauma was assessed with the Dutch version of the Childhood Trauma Questionnaire-Short Form. Urban exposure, expressed as population density, was rated across five levels. Overall, participants had a higher level of education than their parents. This difference was significantly reduced in the patient group, and the healthy siblings displayed intergenerational differences that were in between those of controls and patients. Higher levels of childhood urban exposure were also associated with a smaller intergenerational educational differential. There was no evidence for differential sensitivity to childhood trauma and childhood urbanicity across the three groups. Intergenerational difference in educational achievements is decreased in patients with psychotic disorder and to a lesser extent in siblings of patients with psychotic disorder, and across higher levels of childhood urban exposure. More research is required to better understand the dynamics between early social and cognitive alterations in those at risk in relation to progress through the educational system and to understand the interaction between urban environment and educational outcomes.

Urban and Transport Planning Related Exposures and Mortality: A Health Impact Assessment for Cities.

PubMed

Mueller, Natalie; Rojas-Rueda, David; Basagaña, Xavier; Cirach, Marta; Cole-Hunter, Tom; Dadvand, Payam; Donaire-Gonzalez, David; Foraster, Maria; Gascon, Mireia; Martinez, David; Tonne, Cathryn; Triguero-Mas, Margarita; Valentín, Antònia; Nieuwenhuijsen, Mark

2017-01-01

By 2050, nearly 70% of the global population is projected to live in urban areas. Because the environments we inhabit affect our health, urban and transport designs that promote healthy living are needed. We estimated the number of premature deaths preventable under compliance with international exposure recommendations for physical activity (PA), air pollution, noise, heat, and access to green spaces. We developed and applied the Urban and TranspOrt Planning Health Impact Assessment (UTOPHIA) tool to Barcelona, Spain. Exposure estimates and mortality data were available for 1,357,361 residents. We compared recommended with current exposure levels. We quantified the associations between exposures and mortality and calculated population attributable fractions to estimate the number of premature deaths preventable. We also modeled life-expectancy and economic impacts. We estimated that annually, nearly 20% of mortality could be prevented if international recommendations for performance of PA; exposure to air pollution, noise, and heat; and access to green space were followed. Estimations showed that the greatest portion of preventable deaths was attributable to increases in PA, followed by reductions of exposure to air pollution, traffic noise, and heat. Access to green spaces had smaller effects on mortality. Compliance was estimated to increase the average life expectancy by 360 (95% CI: 219, 493) days and result in economic savings of 9.3 (95% CI: 4.9, 13.2) billion EUR/year. PA factors and environmental exposures can be modified by changes in urban and transport planning. We emphasize the need for a) the reduction of motorized traffic through the promotion of active and public transport and b) the provision of green infrastructure, both of which are suggested to provide opportunities for PA and for mitigation of air pollution, noise, and heat. Citation: Mueller N, Rojas-Rueda D, Basagaña X, Cirach M, Cole-Hunter T, Dadvand P, Donaire-Gonzalez D, Foraster M, Gascon M, Martinez D, Tonne C, Triguero-Mas M, Valentín A, Nieuwenhuijsen M. 2017. Urban and transport planning related exposures and mortality: a health impact assessment for cities. Environ Health Perspect 125:89-96; http://dx.doi.org/10.1289/EHP220.

Supplementary data of “Impacts of mesic and xeric urban vegetation on outdoor thermal comfort and microclimate in Phoenix, AZ”

PubMed Central

Song, Jiyun; Wang, Zhi-Hua

2015-01-01

An advanced Markov-Chain Monte Carlo approach called Subset Simulation is described in Au and Beck (2001) [1] was used to quantify parameter uncertainty and model sensitivity of the urban land-atmospheric framework, viz. the coupled urban canopy model-single column model (UCM-SCM). The results show that the atmospheric dynamics are sensitive to land surface conditions. The most sensitive parameters are dimensional parameters, i.e. roof width, aspect ratio, roughness length of heat and momentum, since these parameters control the magnitude of sensible heat flux. The relative insensitive parameters are hydrological parameters since the lawns or green roofs in urban areas are regularly irrigated so that the water availability for evaporation is never constrained. PMID:26702421

City scale pollen concentration variability

NASA Astrophysics Data System (ADS)

van der Molen, Michiel; van Vliet, Arnold; Krol, Maarten

2016-04-01

Pollen are emitted in the atmosphere both in the country-side and in cities. Yet the majority of the population is exposed to pollen in cities. Allergic reactions may be induced by short-term exposure to pollen. This raises the question how variable pollen concentration in cities are in temporally and spatially, and how much of the pollen in cities are actually produced in the urban region itself. We built a high resolution (1 × 1 km) pollen dispersion model based on WRF-Chem to study a city's pollen budget and the spatial and temporal variability in concentration. It shows that the concentrations are highly variable, as a result of source distribution, wind direction and boundary layer mixing, as well as the release rate as a function of temperature, turbulence intensity and humidity. Hay Fever Forecasts based on such high resolution emission and physical dispersion modelling surpass traditional hay fever warning methods based on temperature sum methods. The model gives new insights in concentration variability, personal and community level exposure and prevention. The model will be developped into a new forecast tool to serve allergic people to minimize their exposure and reduce nuisance, coast of medication and sick leave. This is an innovative approach in hay fever warning systems.

Lead Isotope Characterization of Petroleum Fuels in Taipei, Taiwan

PubMed Central

Yao, Pei-Hsuan; Shyu, Guey-Shin; Chang, Ying-Fang; Chou, Yu-Chen; Shen, Chuan-Chou; Chou, Chi-Su; Chang, Tsun-Kuo

2015-01-01

Leaded gasoline in Taiwan was gradually phased out from 1983 to 2000. However, it is unclear whether unleaded gasoline still contributes to atmospheric lead (Pb) exposure in urban areas. In this study, Pb isotopic compositions of unleaded gasolines, with octane numbers of 92, 95, 98, and diesel from two local suppliers in Taipei were determined by multi-collector inductively coupled plasma mass spectrometry with a two-sigma uncertainty of ± 0.02 %. Lead isotopic ratios of vehicle exhaust (208Pb/207Pb: 2.427, 206Pb/207Pb: 1.148, as estimated from petroleum fuels) overlap with the reported aerosol data. This agreement indicates that local unleaded petroleum fuels, containing 10–45 ng·Pb·g−1, are merely one contributor among various sources to urban aerosol Pb. Additionally, the distinction between the products of the two companies is statistically significant in their individual 208Pb/206Pb ratios (p-value < 0.001, t test). Lead isotopic characterization appears to be applicable as a “fingerprinting” tool for tracing the sources of Pb pollution. PMID:25918913

Physico-chemical characterisation of glass soiling in rural, urban and industrial environments.

PubMed

Lombardo, T; Chabas, A; Verney-Carron, A; Cachier, H; Triquet, S; Darchy, S

2014-01-01

Glass materials are broadly used in the built environment (windows, facades, roofs, museum showcases, and solar panels) due to their optical (transparency) and thermal properties. Their interaction with the multiphase atmospheric medium results in a more or less pronounced transparency loss called soiling. This phenomenon leads to a loss of amenity of artefacts; consequently, high cleaning costs have to be supported by public and private entities. Complete understanding of the nature of surface deposit appears thus extremely important for addressing strategies to control it. The present research is based on the sheltered exposure, in different environments, of durable glass panels during 1 year. At these different locations, airborne pollutant concentrations have also been monitored. Three environments have been investigated: rural (R), urban (U) and industrial (I). Results show that the mass of the deposit and the optical impairment of the glass (haze) are too spread to allow discriminating between different environments. However, the analyses of soluble species and particulate organic matter allow identifying factors responsible for soiling and highlighted the reactivity of deposit to relative humidity which favours post-deposit evolution.

The relationship between new media exposure and fast food consumption among Chinese children and adolescents in school: a rural-urban comparison.

PubMed

Hansstein, Francesca Valeria; Hong, Yu; Di, Chen

2017-09-01

In recent decades, China has experienced an exponential growth in the number of internet users, especially among the youngest population, as well as a rapid proliferation of Western-type fast food restaurants. The health consequences of internet availability and fast food consumption among youth have been largely studied in Western countries, but few studies have focused on China. This paper has two goals. The first is to evaluate the differences in new media exposure and preferences for fast foods between rural and urban areas. The second goal is to test the association between new media exposure and fast food consumption. The targets of this analysis are Chinese children and adolescents aged 6-18 attending school at the time of the interview. Research hypotheses were tested using mean-groups comparisons for differences between rural urban sub-samples, and logistic regressions with odds ratios to estimate the relationship between media exposure and preferences towards fast foods. Cross-sectional data from the 2009 China Health and Nutrition Survey were employed. Watching online videos and playing computer games are behaviors associated with higher probabilities of eating at fast food restaurants in both rural and urban young residents, with higher odds in rural areas. Surfing the internet is associated with higher odds of being overweight in both rural and urban settings. Results also show that children living in rural areas spend significantly more time playing computer games, watching TV and videotapes, but less time doing homework than their urban peers. This paper suggests that monitoring the nutritional effects of new media exposure in China is of key importance in order to develop adequate health promotion policies, in both rural and urban areas.

Recurrent Die-Offs of Adult Coho Salmon Returning to Spawn in Puget Sound Lowland Urban Streams

PubMed Central

Scholz, Nathaniel L.; Myers, Mark S.; McCarthy, Sarah G.; Labenia, Jana S.; McIntyre, Jenifer K.; Ylitalo, Gina M.; Rhodes, Linda D.; Laetz, Cathy A.; Stehr, Carla M.; French, Barbara L.; McMillan, Bill; Wilson, Dean; Reed, Laura; Lynch, Katherine D.; Damm, Steve; Davis, Jay W.; Collier, Tracy K.

2011-01-01

Several Seattle-area streams in Puget Sound were the focus of habitat restoration projects in the 1990s. Post-project effectiveness monitoring surveys revealed anomalous behaviors among adult coho salmon returning to spawn in restored reaches. These included erratic surface swimming, gaping, fin splaying, and loss of orientation and equilibrium. Affected fish died within hours, and female carcasses generally showed high rates (>90%) of egg retention. Beginning in the fall of 2002, systematic spawner surveys were conducted to 1) assess the severity of the adult die-offs, 2) compare spawner mortality in urban vs. non-urban streams, and 3) identify water quality and spawner condition factors that might be associated with the recurrent fish kills. The forensic investigation focused on conventional water quality parameters (e.g., dissolved oxygen, temperature, ammonia), fish condition, pathogen exposure and disease status, and exposures to metals, polycyclic aromatic hydrocarbons, and current use pesticides. Daily surveys of a representative urban stream (Longfellow Creek) from 2002–2009 revealed premature spawner mortality rates that ranged from 60–100% of each fall run. The comparable rate in a non-urban stream was <1% (Fortson Creek, surveyed in 2002). Conventional water quality, pesticide exposure, disease, and spawner condition showed no relationship to the syndrome. Coho salmon did show evidence of exposure to metals and petroleum hydrocarbons, both of which commonly originate from motor vehicles in urban landscapes. The weight of evidence suggests that freshwater-transitional coho are particularly vulnerable to an as-yet unidentified toxic contaminant (or contaminant mixture) in urban runoff. Stormwater may therefore place important constraints on efforts to conserve and recover coho populations in urban and urbanizing watersheds throughout the western United States. PMID:22194802

Accelerated Test Method for Corrosion Protective Coatings Project

NASA Technical Reports Server (NTRS)

Falker, John; Zeitlin, Nancy; Calle, Luz

2015-01-01

This project seeks to develop a new accelerated corrosion test method that predicts the long-term corrosion protection performance of spaceport structure coatings as accurately and reliably as current long-term atmospheric exposure tests. This new accelerated test method will shorten the time needed to evaluate the corrosion protection performance of coatings for NASA's critical ground support structures. Lifetime prediction for spaceport structure coatings has a 5-year qualification cycle using atmospheric exposure. Current accelerated corrosion tests often provide false positives and negatives for coating performance, do not correlate to atmospheric corrosion exposure results, and do not correlate with atmospheric exposure timescales for lifetime prediction.

Pathways to Aggression in Urban Elementary School Youth

ERIC Educational Resources Information Center

Ozkol, Hivren; Zucker, Marla; Spinazzola, Joseph

2011-01-01

This study examined the pathways from violence exposure to aggressive behaviors in urban, elementary school youth. We utilized structural equation modeling to examine putative causal pathways between children's exposure to violence, development of posttraumatic stress symptoms, permissive attitudes towards violence, and engagement in aggressive…

Timescale Correlation between Marine Atmospheric Exposure and Accelerated Corrosion Testing

NASA Technical Reports Server (NTRS)

Montgomery, Eliza L.; Calle, Luz Marina; Curran, Jerone C.; Kolody, Mark R.

2011-01-01

Evaluation of metal-based structures has long relied on atmospheric exposure test sites to determine corrosion resistance in marine environments. Traditional accelerated corrosion testing relies on mimicking the exposure conditions, often incorporating salt spray and ultraviolet (UV) radiation, and exposing the metal to continuous or cyclic conditions of the corrosive environment. Their success for correlation to atmospheric exposure is often a concern when determining the timescale to which the accelerated tests can be related. Accelerated laboratory testing, which often focuses on the electrochemical reactions that occur during corrosion conditions, has yet to be universally accepted as a useful tool in predicting the long term service life of a metal despite its ability to rapidly induce corrosion. Although visual and mass loss methods of evaluating corrosion are the standard and their use is imperative, a method that correlates timescales from atmospheric exposure to accelerated testing would be very valuable. This work uses surface chemistry to interpret the chemical changes occurring on low carbon steel during atmospheric and accelerated corrosion conditions with the objective of finding a correlation between its accelerated and long-term corrosion performance. The current results of correlating data from marine atmospheric exposure conditions at the Kennedy Space Center beachside corrosion test site, alternating seawater spray, and immersion in typical electrochemical laboratory conditions, will be presented. Key words: atmospheric exposure, accelerated corrosion testing, alternating seawater spray, marine, correlation, seawater, carbon steel, long-term corrosion performance prediction, X-ray photoelectron spectroscopy.

Modeling the Surface Energy Balance of the Core of an Old Mediterranean City: Marseille.

NASA Astrophysics Data System (ADS)

Lemonsu, A.; Grimmond, C. S. B.; Masson, V.

2004-02-01

The Town Energy Balance (TEB) model, which parameterizes the local-scale energy and water exchanges between urban surfaces and the atmosphere by treating the urban area as a series of urban canyons, coupled to the Interactions between Soil, Biosphere, and Atmosphere (ISBA) scheme, was run in offline mode for Marseille, France. TEB's performance is evaluated with observations of surface temperatures and surface energy balance fluxes collected during the field experiments to constrain models of atmospheric pollution and transport of emissions (ESCOMPTE) urban boundary layer (UBL) campaign. Particular attention was directed to the influence of different surface databases, used for input parameters, on model predictions. Comparison of simulated canyon temperatures with observations resulted in improvements to TEB parameterizations by increasing the ventilation. Evaluation of the model with wall, road, and roof surface temperatures gave good results. The model succeeds in simulating a sensible heat flux larger than heat storage, as observed. A sensitivity comparison using generic dense city parameters, derived from the Coordination of Information on the Environment (CORINE) land cover database, and those from a surface database developed specifically for the Marseille city center shows the importance of correctly documenting the urban surface. Overall, the TEB scheme is shown to be fairly robust, consistent with results from previous studies.

Human health risk assessment of lead pollution in atmospheric deposition in Baoshan District, Shanghai.

PubMed

Chen, Yuanyuan; Wang, Jun; Shi, Guitao; Sun, Xiaojing; Chen, Zhenlou; Xu, Shiyuan

2011-12-01

The lead (Pb) content in atmospheric deposition was determined at 42 sampling sites in Baoshan District of Shanghai, China. Based on exposure and dose-response assessments, the health risk caused by Pb exposure in atmospheric deposition was investigated. The results indicated that Pb was significantly accumulated in atmospheric deposition. The spatial distribution of Pb was mapped by geostatistical analysis, and the results showed that pollution hotspots were present at traffic and industrial zones. Ingestion was the main route of Pb exposure in both adults and children. For children the risk value was above 1, whereas it was below 1 for the adult group. Therefore, children belong to the high-risk group for Pb exposure from atmospheric deposition in the observed area of Shanghai, China.

Effects of byproducts amended lead contaminated urban soils on collard yield

USDA-ARS?s Scientific Manuscript database

Lead (Pb) has been used to produce materials and manufactured products for many years. In urban areas and industrial centers atmospheric lead deposition could be very high. Urban environments in general received high deposition of lead due to leaded gasoline use, industrial activity and abandoned ...

The energy balance of an urban area: Examining temporal and spatial variability through measurements, remote sensing and modeling

NASA Astrophysics Data System (ADS)

Offerle, Brian

Urban environmental problems related to air quality, thermal stress, issues of water demand and quality, all of which are linked directly or indirectly to urban climate, are emerging as major environmental concerns at the start of the 21st century. Thus there are compelling social, political and economic, and scientific reasons that make the study and understanding of the fundamental causes of urban climates critically important. This research addresses these topics through an intensive study of the surface energy balance of Lodz, Poland. The research examines the temporal variability in long-term measurements of urban surface-atmosphere exchange at a downtown location and the spatial variability of this exchange over distinctly different neighborhoods using shorter-term observations. These observations provide the basis for an evaluation of surface energy balance models. Monthly patterns in energy exchange are consistent from year-to-year with variability determined by net radiation and the timing and amount of precipitation. Spatial variability can be determined from plan area fractions of vegetation and impervious surface, though heat storage exerts a strong control on shorter term variability of energy exchange, within and between locations in an urban area. Anthropogenic heat fluxes provide most of the energy driving surface-atmosphere exchange in winter, From a modeling perspective, sensible heat fluxes can be reliably determined from radiometrically sensed surface temperatures and spatially representative surface-atmosphere exchange in an urban area can be determined from satellite remote sensing products. Models of the urban surface energy balance showed good agreement with mean values of energy exchange and under most conditions represented the temporal variability due to synoptic and shorter time scale forcing well.

Urban bioclimatology.

PubMed

Mayer, H

1993-11-15

This article deals with the part of urban climatology which is of particular relevance to human beings. Presented first is a summary of all human biometerologically effective complexes, as well as other factors which are relevant to urban planning and which depend on atmospheric conditions in urban structures in a direct or indirect manner. Later, methods for human biometerologically significant assessment of thermal and air pollution components of the urban climate are discussed in detail, because these components can be strongly influenced by urban planning. The application of these methods is illustrated by some results of appropriate investigations in urban areas.

Exposures to Transit and Other Sources of Noise among New York City Residents

PubMed Central

Neitzel, Richard L.; Gershon, Robyn R. M.; McAlexander, Tara P.; Magda, Lori A.; Pearson, Julie M.

2015-01-01

To evaluate the contributions of common noise sources to total annual noise exposures among urban residents and workers, we estimated exposures associated with five common sources (use of mass transit, occupational and non-occupational activities, MP3 player and stereo use, and time at home and doing other miscellaneous activities) among a sample of over 4500 individuals in New York City (NYC). We then evaluated the contributions of each source to total noise exposure and also compared our estimated exposures to the recommended 70 dBA annual exposure limit. We found that one in ten transit users had noise exposures in excess of the recommended exposure limit from their transit use alone. When we estimated total annual exposures, 90% of NYC transit users and 87% of nonusers exceeded the recommended limit. MP3 player and stereo use, which represented a small fraction of the total annual hours for each subject on average, was the primary source of exposure among the majority of urban dwellers we evaluated. Our results suggest that the vast majority of urban mass transit riders may be at risk of permanent, irreversible noise-induced hearing loss and that, for many individuals, this risk is driven primarily by exposures other than occupational noise. PMID:22088203

Assessing the Role of Sewers and Atmospheric Deposition as Nitrate Contamination Sources to Urban Surface Waters using Stable Nitrate Isotopes

NASA Astrophysics Data System (ADS)

Sikora, M. T.; Elliott, E. M.

2009-12-01

Excess nitrate (NO3-) contributes to the overall degraded quality of streams in many urban areas. These systems are often dominated by impervious surfaces and storm sewers that can route atmospherically deposited nitrogen, from both wet and dry deposition, to waterways. Moreover, in densely populated watersheds there is the potential for interaction between urban waterways and sewer systems. The affects of accumulated nitrate in riverine and estuary systems include low dissolved oxygen, loss of species diversity, increased mortality of aquatic species, and general eutrophication of the waterbody. However, the dynamics of nitrate pollution from each source and it’s affect on urban waterways is poorly constrained. The isotopes of nitrogen and oxygen in nitrate have been proven effective in helping to distinguish contamination sources to ground and surface waters. In order to improve our understanding of urban nitrate pollution sources and dynamics, we examined nitrate isotopes (δ15N and δ18O) in base- and stormflow samples collected over a two-year period from a restored urban stream in Pittsburgh, Pennsylvania (USA). Nine Mile Run drains a 1,600 hectare urban watershed characterized by 38% impervious surface cover. Prior work has documented high nitrate export from the watershed (~19 kg NO3- ha-1 yr-1). Potential nitrate sources to the watershed include observed sewer overflows draining directly to the stream, as well as atmospheric deposition (~23 kg NO3- ha-1 yr-1). In this and other urban systems with high percentages of impervious surfaces, there is likely minimal input from nitrate derived from soil or fertilizer. In this presentation, we examine spatial and temporal patterns in nitrate isotopic composition collected at five locations along Nine Mile Run characterized by both sanitary and combined-sewer cross-connections. Preliminary isotopic analysis of low-flow winter streamwater samples suggest nitrate export from Nine Mile Run is primarily influenced by inputs of human waste despite high rates of atmospheric nitrate deposition. Further isotopic analysis of nitrate will examine seasonal variations in nitrate sources; compare nitrate dynamics and sources during low- versus high-flows, and the influence of interannual climatic variability on nitrate export.

Impacts of heterogeneous reactions to atmospheric peroxides: Observations and budget analysis study

NASA Astrophysics Data System (ADS)

Qin, Mengru; Chen, Zhongming; Shen, Hengqing; Li, Huan; Wu, Huihui; Wang, Yin

2018-06-01

Atmospheric peroxides play important roles in atmospheric chemistry, acting as reactive oxidants and reservoirs of HOX and ROX radicals. Field measurements of atmospheric peroxides were conducted over urban Beijing from 2015 to 2016, including dust storm days, haze days and different seasons. We employed a box model based on RACM2 mechanism to conduct concentration simulation and budget analysis of hydrogen peroxide (H2O2) and peroxyacetic acid (PAA). In this study, heterogeneous reaction is found to be a significant sink for atmospheric H2O2 and PAA in urban Beijing. Here, we recommend a suitable uptake coefficient formula considering the water effect for model research of peroxides. It is found that H2O2 and PAA unexpectedly maintained considerable concentrations on haze days, even higher than that on non-haze days. This phenomenon is mainly ascribed to relatively high levels of volatile organic compounds and ozone on haze days. In addition, high levels of water vapor in pollution episode can promote not only the heterogeneous uptake to aerosol phase but also the production of H2O2. Atmospheric PAA formation is suggested to be sensitive to alkenes and NOX in urban Beijing. In particular, with the help of peroxides, sulfate formation rate from heterogeneous uptake could increase by ∼4 times on haze days, indicating the potential effect of peroxides on enhancement of aerosol oxidative property and secondary sulfate formation.

Model analysis of urbanization impacts on boundary layer meteorology under hot weather conditions: a case study of Nanjing, China

NASA Astrophysics Data System (ADS)

Chen, Lei; Zhang, Meigen; Wang, Yongwei

2016-08-01

The Weather Research and Forecasting (WRF) model, configured with a single-layer urban canopy model, was employed to investigate the influence of urbanization on boundary layer meteorological parameters during a long-lasting heat wave. This study was conducted over Nanjing city, East China, from 26 July to 4 August 2010. The impacts of urban expansion and anthropogenic heat (AH) release were simulated to quantify their effects on 2-m temperature, 2-m water vapor mixing ratio, and 10-m wind speed and heat stress index. Urban sprawl increased the daily 2-m temperature in urbanized areas by around 1.6 °C and decreased the urban diurnal temperature range (DTR) by 1.24 °C. The contribution of AH release to the atmospheric warming was nearly 22 %, but AH had little influence on the DTR. The urban regional mean surface wind speed decreased by about 0.4 m s-1, and this decrease was successfully simulated from the surface to 300 m. The influence of urbanization on 2-m water vapor mixing ratio was significant over highly urbanized areas with a decrease of 1.1-1.8 g kg-1. With increased urbanization ratio, the duration of the inversion layer was about 4 h shorter, and the lower atmospheric layer was less stable. Urban heat island (UHI) intensity was significantly enhanced when synthesizing both urban sprawl and AH release and the daily mean UHI intensity increased by 0.74 °C. Urbanization increased the time under extreme heat stress (about 40 %) and worsened the living environment in urban areas.

ADDRESSING HUMAN EXPOSURES TO AIR POLLUTANTS AROUND BUILDINGS IN URBAN AREAS WITH COMPUTATIONAL FLUID DYNAMICS MODELS

EPA Science Inventory

This paper discusses the status and application of Computational Fluid Dynamics (CFD) models to address challenges for modeling human exposures to air pollutants around urban building microenvironments. There are challenges for more detailed understanding of air pollutant sour...

Quantifying road dust resuspension in urban environment by Multilinear Engine: A comparison with PMF2

NASA Astrophysics Data System (ADS)

Amato, F.; Pandolfi, M.; Escrig, A.; Querol, X.; Alastuey, A.; Pey, J.; Perez, N.; Hopke, P. K.

Atmospheric PM pollution from traffic comprises not only direct emissions but also non-exhaust emissions because resuspension of road dust that can produce high human exposure to heavy metals, metalloids, and mineral matter. A key task for establishing mitigation or preventive measures is estimating the contribution of road dust resuspension to the atmospheric PM mixture. Several source apportionment studies, applying receptor modeling at urban background sites, have shown the difficulty in identifying a road dust source separately from other mineral sources or vehicular exhausts. The Multilinear Engine (ME-2) is a computer program that can solve the Positive Matrix Factorization (PMF) problem. ME-2 uses a programming language permitting the solution to be guided toward some possible targets that can be derived from a priori knowledge of sources (chemical profile, ratios, etc.). This feature makes it especially suitable for source apportionment studies where partial knowledge of the sources is available. In the present study ME-2 was applied to data from an urban background site of Barcelona (Spain) to quantify the contribution of road dust resuspension to PM 10 and PM 2.5 concentrations. Given that recently the emission profile of local resuspended road dust was obtained (Amato, F., Pandolfi, M., Viana, M., Querol, X., Alastuey, A., Moreno, T., 2009. Spatial and chemical patterns of PM 10 in road dust deposited in urban environment. Atmospheric Environment 43 (9), 1650-1659), such a priori information was introduced in the model as auxiliary terms of the object function to be minimized by the implementation of the so-called "pulling equations". ME-2 permitted to enhance the basic PMF solution (obtained by PMF2) identifying, beside the seven sources of PMF2, the road dust source which accounted for 6.9 μg m -3 (17%) in PM 10, 2.2 μg m -3 (8%) of PM 2.5 and 0.3 μg m -3 (2%) of PM 1. This reveals that resuspension was responsible of the 37%, 15% and 3% of total traffic emissions respectively in PM 10, PM 2.5 and PM 1. Therefore the overall traffic contribution resulted in 18 μg m -3 (46%) in PM 10, 14 μg m -3 (51%) in PM 2.5 and 8 μg m -3 (48%) in PM 1. In PMF2 this mass explained by road dust resuspension was redistributed among the rest of sources, increasing mostly the mineral, secondary nitrate and aged sea salt contributions.

Cognitive disorders in children associated with urban vehicular emissions.

PubMed

Annavarapu, Ramesh Naidu; Kathi, Srujana

2016-01-01

This review introduces recent advances in an emerging research area that is focussed on studying the effect of exposure to vehicular emissions on cognition, with specific attention to children from urban environments. Today, air pollution is a global environmental issue, especially in urban environments, emitting particulate matter (PM), nitrogen dioxide (NO2), carbon monoxide (CO), volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) into the surroundings. The association of exposure to urban air pollution and cognitive disorders in children is a major cause of concern. We review recent findings associated with exposure to air pollutants and explained the potential mechanisms driving oxidative stress in living systems. An attempt has been made to investigate the cognitive effects of air pollutants leading to neurodegeneration, neurodysfunction, attention deficit/hypersensitivity deficiencies and autism in children. Accumulating evidence suggests that urban air pollution may have significant impact on central nervous system (CNS) of the developing brain. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dietary exposure to aluminium of urban residents from cities in South China.

PubMed

Jiang, Qi; Wang, Jing; Li, Min; Liang, Xuxia; Dai, Guangwei; Hu, Zhikun; Wen, Jian; Huang, Qiong; Zhang, Yonghui

2013-01-01

A dietary survey was conducted over three consecutive days by using 24-hour dietary recall in the Pearl River Delta of South China to investigate the dietary consumption status. A total of 1702 food samples, 22 food groups, were collected, and aluminium concentrations of foods were determined by using ICP-MS. Weekly dietary exposure to aluminium of the average urban residents of South China was estimated to be 1.5 mg kg⁻¹ body weight, which amounted to 76% of the provisional tolerable weekly intake. Wheat-made products (53.5%) contributed most to the dietary exposure, followed by vegetables (12.2%). The high-level consumers' weekly exposure to aluminium was 11.1 mg kg⁻¹ body weight, which amounted to 407% of the provisional tolerable weekly intake. The results indicated that the general urban residents in South China might be safe from aluminium exposure, but the high-level consumers might be at some risk of aluminium exposure. The foods contributing to aluminium exposure were processed food with aluminium-containing food additives. It is necessary to take effective measures to control the overuse of aluminium-containing food additives.

Geochemical legacies and the future health of cities: A tale of two neurotoxins in urban soils

USGS Publications Warehouse

Fillipelli, Gabriel M.; Risch, Martin R.; Laidlaw, Mark A. S.; Nichols, Deborah E.; Crewe, Julie

2015-01-01

Acute exposure to lead (Pb), a powerful neurotoxin to which children are particularly susceptible, has largely been eliminated in the U.S. and other countries through policy-based restrictions on leaded gasoline and lead-based paints. But the legacy of these sources remains in the form of surface soil Pb contamination, a common problem in cities and one that has only recently emerged as a widespread chronic exposure mechanism in cities. Some urban soils are also contaminated with another neurotoxin, mercury (Hg). The greatest human exposure to Hg is through fish consumption, so eating fish caught in urban areas presents risks for toxic Hg exposure. The potential double impact of chronic exposure to these two neurotoxins is pronounced in cities. Overall, there is a paradigmatic shift from reaction to and remediation of acute exposures towards a more nuanced understanding of the dynamic cycling of persistent environmental contaminants with resultant widespread and chronic exposure of inner-city dwellers, leading to chronic toxic illness and disability at substantial human and social cost.

National Urban Database and Access Portal Tool

EPA Science Inventory

Based on the need for advanced treatments of high resolution urban morphological features (e.g., buildings, trees) in meteorological, dispersion, air quality and human exposure modeling systems for future urban applications, a new project was launched called the National Urban Da...

Heat exposure in cities: combining the dynamics of temperature and population

NASA Astrophysics Data System (ADS)

Hu, L.; Wilhelmi, O.; Uejio, C. K.

2017-12-01

Assessment of human exposure to extreme heat requires the distributions of temperature and population. However, both variables are dynamic, thus presenting many challenges in capturing temperature and population patterns spatially and over time in an urban context. This study aims to improve the understanding of spatiotemporal patterns of urban population exposure to heat, taking Chicago, USA as an example. We estimate the hourly, geographically variable, population distribution considering commute of workers and students in a regular weekday and analyze the diurnal air temperature patterns during different meteorological conditions from satellite observations. The results show a relatively larger temperature increase in less urbanized areas during extreme heat events (EHEs), resulting in a spatially homogeneous temperature distribution over Chicago Metropolitan area. A lake cooling effect is weaker during EHEs. Population dynamics due to daily commute determine higher population density in more urbanized areas during daytime. The city-wide analysis reveals that the exposure is more sensitive to the nighttime temperature increases, and EHEs enhance this sensitivity. The high exposure hotspots are identified at the northwest Chicago, Cicero and Oak Park areas, where the influence from Lake Michigan is weakened, while the spatial extent of high outdoor exposure areas varies diurnally. This study's findings have potential to better inform general heat mitigation strategies during hot summer months and facilitate emergency response during EHEs. Availability of remotely-sensed temperature observations as well as the workers and students commute-adjusted population data allows for the adoption of this study's methodology in other major metropolitan areas. A better understanding of space-time patterns of urban population's exposure to heat will further enable local decision makers to mitigate extreme heat health risks and develop more targeted heat preparedness and response strategies.

Spatial and Seasonal Distributions of Current Use Pesticides (CUPs) in the Atmospheric Particulate Phase in the Great Lakes Region.

PubMed

Wang, Shaorui; Salamova, Amina; Hites, Ronald A; Venier, Marta

2018-06-05

The authors analyzed spatial and seasonal variations of current use pesticides (CUPs) levels in the atmospheric particulate phase in the Great Lakes basin. Twenty-four hour air samples were collected at six sites (two urban, two rural, and two remote) in 2015. The concentrations of 15 CUPs, including nine pyrethroid insecticides, four herbicides, one organophosphate insecticide, and one fungicide, were measured. The total CUPs concentrations were higher at the urban sites (0.38-1760 pg/m 3 ) than at the rural and remote sites (0.07-530 pg/m 3 ). The most abundant CUPs were pyrethroid insecticides at the urban sites. The levels of the other CUPs did not vary much among the six sites, except at the most remote site at Eagle Harbor, where the levels were significantly lower. Chlorothalonil was the most frequently detected CUP, which was detected in more than 76% of the samples. The atmospheric concentrations of total pyrethroid insecticides and total herbicides were correlated with local human population and developed land use. Significantly higher concentrations of most CUPs were observed in the warmer months than in the colder months at all sites. In addition to agricultural applications, which occur during the warmer months, the CUPs atmospheric concentrations may also be influenced by nonagricultural activities and the urban development.

Radiation dose predictions for SPE events during solar cycle 23 from NASA's Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model

NASA Astrophysics Data System (ADS)

Mertens, Christopher; Blattnig, Steve; Slaba, Tony; Kress, Brian; Wiltberger, Michael; Solomon, Stan

NASA's High Charge and Energy Transport (HZETRN) code is a deterministic model for rapid and accurate calculations of the particle radiation fields in the space environment. HZETRN is used to calculate dosimetric quantities on the International Space Station (ISS) and assess astronaut risk to space radiations, including realistic spacecraft and human geometry for final exposure evaluation. HZETRN is used as an engineering design tool for materials research for radiation shielding protection. Moreover, it is used to calculate HZE propagation through the Earth and Martian atmospheres, and to evaluate radiation exposures for epidemiological studies. A new research project has begun that will use HZETRN as the transport engine for the development of a nowcast prediction of air-crew radiation exposure for both background galactic cosmic ray (GCR) exposure and radiation exposure during solar particle events (SPE) that may accompany solar storms. The new air-crew radiation exposure model is called the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model, which utilizes real-time observations from ground-based, atmospheric, and satellite measurements. In this paper, we compute the global distribution of atmospheric radiation dose for several SPE events during solar cycle 23, with particular emphasis on the high-latitude and polar region. We also characterize the suppression of the geomagnetic cutoff rigidity during these storm periods and their subsequent influence on atmospheric radiation exposure.

Respiratory damage in children exposed to urban pollution.

PubMed

Calderón-Garcidueñas, Lilian; Mora-Tiscareño, Antonieta; Fordham, Lynn A; Valencia-Salazar, Gildardo; Chung, Charles J; Rodriguez-Alcaraz, Antonio; Paredes, Rogelio; Variakojis, Daina; Villarreal-Calderón, Anna; Flores-Camacho, Lourdes; Antunez-Solis, Angelina; Henríquez-Roldán, Carlos; Hazucha, Milan J

2003-08-01

Southwest Metropolitan Mexico City (SWMMC) children are chronically exposed to complex mixtures of air pollutants. In a cross-sectional arm of our study, we investigated the association between exposure to SWMMC atmosphere and nasal abnormalities, hyperinflation, and interstitial markings assessed by chest X-rays, lung function changes, several serum cytokines, and endothelin-1 in 174 children aged 5-17 years vs. 27 control children residents in low-polluted areas. Control children had no nasal lesions, and only one child showed an abnormal chest X-ray. SWMMC children exhibited nasal abnormalities (22%), hyperinflation (67%), interstitial markings (49%), and a mild restrictive pattern by spirometry (10%). Interstitial markings were associated with a decrease in predicted values of FEF(25-75), FEF(75), and the FEV(1)/FVC ratio. Boys had a higher probability of developing interstitial markings with age (P = 0.004). Blood smear findings included toxic granulations in neutrophils and schistocytes. SWMMC children had more serum IL10 and IL6 and less IL8 than controls. In a longitudinal arm of our study, we found a significant seasonal drop in FVC and FEV(1) associated with a 6-month period of high ozone and PM(10) levels. Our data strongly suggest that a lifelong exposure to urban air pollution causes respiratory damage in children. Moreover, a cytokine network becomes imbalanced, with a shift towards upregulation of anti-inflammatory cytokines. Consequently, these children are potentially at risk for developing chronic lung disease and other systemic effects later in life. Copyright 2003 Wiley-Liss, Inc.

SPATIAL ANALYSIS OF AIR POLLUTION AND DEVELOPMENT OF A LAND-USE REGRESSION ( LUR ) MODEL IN AN URBAN AIRSHED

EPA Science Inventory

The Detroit Children's Health Study is an epidemiologic study examining associations between chronic ambient environmental exposures to gaseous air pollutants and respiratory health outcomes among elementary school-age children in an urban airshed. The exposure component of this...

PREDICTING PARTICULATE (PM-10) FREQUENCY DISTRIBUTIONS FOR URBAN POPULATIONS USING A RANDOM COMPONENT SUPERPOSITION MODEL (RCS) MODEL

EPA Science Inventory

Health risk evaluations usually require the frequency distribution of personal exposures of a given population. For particles, personal exposure field studies have been conducted in only a few urban areas, such as Riverside, CA; Philipsburg, NJ; and Toronto, Ontario. This paper...

Lead in Urban Soils: A Real or Perceived Concern for Urban Agriculture?

PubMed

Brown, Sally L; Chaney, Rufus L; Hettiarachchi, Ganga M

2016-01-01

Urban agriculture is growing in cities across the United States. It has the potential to provide multiple benefits, including increased food security. Concerns about soil contamination in urban areas can be an impediment to urban agriculture. Lead is the most common contaminant in urban areas. In this paper, direct (soil ingestion via outdoor and indoor exposure) and indirect (consumption of food grown in Pb-contaminated soils) exposure pathways are reviewed. It is highly unlikely that urban agriculture will increase incidences of elevated blood Pb for children in urban areas. This is due to the high likelihood that agriculture will improve soils in urban areas, resulting in reduced bioavailability of soil Pb and reduced fugitive dust. Plant uptake of Pb is also typically very low. The exceptions are low-growing leafy crops where soil-splash particle contamination is more likely and expanded hypocotyl root vegetables (e.g., carrot). However, even with higher bioaccumulation factors, it is not clear that the Pb in root vegetables or any other crops will be absorbed after eating. Studies have shown limited absorption of Pb when ingested with food. Best management practices to assure minimal potential for exposure are also common practices in urban gardens. These include the use of residuals-based composts and soil amendments and attention to keeping soil out of homes. This review suggests that benefits associated with urban agriculture far outweigh any risks posed by elevated soil Pb. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Characteristics of atmospheric ammonia and its relationship with vehicle emissions in a megacity in China

NASA Astrophysics Data System (ADS)

Wang, Ruyu; Ye, Xingnan; Liu, Yuxuan; Li, Haowen; Yang, Xin; Chen, Jianmin; Gao, Wei; Yin, Zi

2018-06-01

Atmospheric ammonia plays an important role in haze formation in East China. In this study, long-term measurements of NH3 concentrations were implemented at urban, suburban, and tunnel sites in Shanghai, the largest city in East China. The average monthly ammonia concentrations at the urban site varied from 3.7 ppb to 14.5 ppb and exhibited the highest levels in summer and lowest levels in winter, indicating that the biological emissions and agriculture in the surrounding areas are important contributors. The suburban NH3 levels were significantly higher in autumn compared to those at the urban site, indicating the important contribution of agricultural activities. Regardless of the season, the difference of NH3 concentrations between the tunnel and urban sites remained almost constant. On average, the tunnel NH3 level was three times higher than that of the nearby urban site, indicating strong vehicle NH3 emissions in the tunnel. The tunnel NH3 levels on weekdays were comparable to those on weekends, a result that was in agreement with the daily average traffic volume. It was estimated that the vehicle emissions contributed 12.6-24.6% of the atmospheric NH3 in the urban area and 3.8-7.5% for the whole area of Shanghai. Our results suggest that vehicle NH3 emissions should be considered, although agricultural emissions are still more important for mitigating severe haze pollution during wintertime in the megacities of China.

Impact of Land-Use and Land-Cover Change on urban air quality in representative cities of China

NASA Astrophysics Data System (ADS)

Sun, L.; Wei, J.; Duan, D. H.; Guo, Y. M.; Yang, D. X.; Jia, C.; Mi, X. T.

2016-05-01

The atmospheric particulate pollution in China is getting worse. Land-Use and Land-Cover Change (LUCC) is a key factor that affects atmospheric particulate pollution. Understanding the response of particulate pollution to LUCC is necessary for environmental protection. Eight representative cities in China, Qingdao, Jinan, Zhengzhou, Xi'an, Lanzhou, Zhangye, Jiuquan, and Urumqi were selected to analyze the relationship between particulate pollution and LUCC. The MODIS (MODerate-resolution Imaging Spectroradiometer) aerosol product (MOD04) was used to estimate atmospheric particulate pollution for nearly 10 years, from 2001 to 2010. Six land-use types, water, woodland, grassland, cultivated land, urban, and unused land, were obtained from the MODIS land cover product (MOD12), where the LUCC of each category was estimated. The response of particulate pollution to LUCC was analyzed from the above mentioned two types of data. Moreover, the impacts of time-lag and urban type changes on particulate pollution were also considered. Analysis results showed that due to natural factors, or human activities such as urban sprawl or deforestation, etc., the response of particulate pollution to LUCC shows obvious differences in different areas. The correlation between particulate pollution and LUCC is lower in coastal areas but higher in inland areas. The dominant factor affecting urban air quality in LUCC changes from ocean, to woodland, to urban land, and eventually into grassland or unused land when moving from the coast to inland China.

Sediment exchange to mitigate pollutant exposure in urban soil.

PubMed

Walsh, Daniel; Glass, Katherine; Morris, Samantha; Zhang, Horace; McRae, Isabel; Anderson, Noel; Alfieri, Alysha; Egendorf, Sara Perl; Holberton, Shana; Owrang, Shahandeh; Cheng, Zhongqi

2018-05-15

Urban soil is an ongoing source for lead (Pb) and other pollutant exposure. Sources of clean soil that are locally-available, abundant and inexpensive are needed to place a protective cover layer over degraded urban soil to eliminate direct and indirect pollutant exposures. This study evaluates a novel sediment exchange program recently established in New York City (NYC Clean Soil Bank, CSB) and found that direct exchange of surplus sediment extracted from urban construction projects satisfies these criteria. The CSB has high total yield with 4.2 × 10 5  t of sediment exchanged in five years. Average annual yield (8.5 × 10 4  t yr -1 ) would be sufficient to place a 15-cm (6-in.) sediment cover layer over 3.2 × 10 5  m 2 (80 acres) of impacted urban soil or 1380 community gardens. In a case study of sediment exchange to mitigate community garden soil contamination, Pb content in sediment ranged from 2 to 5 mg kg -1 . This sediment would reduce surface Pb concentrations more than 98% if it was used to encapsulate soil with Pb content exceeding USEPA residential soil standards (400 mg kg -1 ). The maximum observed sediment Pb content is a factor of 42 and 71 lower than median surface soil and garden soil in NYC, respectively. All costs (transportation, chemical testing, etc.) in the CSB are paid by the donor indicating that urban sediment exchange could be an ultra-low-cost source for urban soil mitigation. Urban-scale sediment exchange has advantages over existing national- or provincial-scale sediment exchanges because it can retain and upcycle local sediment resources to attain their highest and best use (e.g. lowering pollutant exposure), achieve circular urban materials metabolism, improve livability and maximize urban sustainability. Published by Elsevier Ltd.

Bioavailability evaluation, uptake of heavy metals and potential health risks via dietary exposure in urban-industrial areas.

PubMed

Yousaf, Balal; Liu, Guijian; Wang, Ruwei; Imtiaz, Muhammad; Zia-Ur-Rehman, Muhammad; Munir, Mehr Ahmed Mujtaba; Niu, Zhiyuan

2016-11-01

A verity of human activities i.e. urbanization and industrialization have been resulted serious environmental contaminations by heavy metals in all over the world. The settlement of populations in urban and nearby industrial areas for economic development has significant share in their exposure to these metallic contaminants. Depending on the nature and type of the pollutants, targeted urban-industrial environments can have harmful and chronic health risk impacts on exposed local inhabitants and may require detoxification, healing and remedial therapy. Consequently, environmental monitoring as well as human health risk assessments of urban environments under industrial influence are key dominant features. We believe this work will provide new insights into the studies of metals exposure and associated health risks in emerging industrials cities of developing countries. Present study aimed to study the bioavailability of metals, quantify the changeability in soil and vegetable metal concentrations and estimation of human health risks via dietary exposure, focusing on urban-industrial environment. Soil and vegetable samples were collected in six random sites within the urban, periurban and industrial areas and analyzed for metal concentrations. In addition, risk assessment model proposed by US-EPA was employed to estimate the potential health risk of heavy metals via dietary intake. Results indicated that the heavy metal concentrations were noteworthy in periurban and urban-industrial areas. However, contamination levels varied with the type of vegetable, and the point source pollution such as traffic, urban wastes and industrial effluent. According to the estimated THQ and HI values for non-carcinogenic risk, little or no negative impact of heavy metals was observed on local inhabitants. However, the concentrations of Cr, Cd, Pb and Ni were nearly closed to the permissible limits described by US-EPA in urban-industrial areas. Conclusively, some efficient remedial strategies should be focus to overcome the increasing levels of Cr, Cd, Pb and Ni in this study area to protect the health of local inhabitants.

Risk assessment of population inhalation exposure to volatile organic compounds and carbonyls in urban China.

PubMed

Du, Zhengjian; Mo, Jinhan; Zhang, Yinping

2014-12-01

Over the past three decades, China has experienced rapid urbanization. The risks to its urban population posed by inhalation exposure to hazardous air pollutants (HAPs) have not been well characterized. Here, we summarize recent measurements of 16 highly prevalent HAPs in urban China and compile their distribution inputs. Based on activity patterns of urban Chinese working adults, we derive personal exposures. Using a probabilistic risk assessment method, we determine cancer and non-cancer risks for working females and males. We also assess the uncertainty associated with risk estimates using Monte Carlo simulation, accounting for variations in HAP concentrations, cancer potency factors (CPFs) and inhalation rates. Average total lifetime cancer risks attributable to HAPs are 2.27×10(-4) (2.27 additional cases per 10,000 people exposed) and 2.93×10(-4) for Chinese urban working females and males, respectively. Formaldehyde, 1,4-dichlorobenzene, benzene and 1,3-butadiene are the major risk contributors yielding the highest median cancer risk estimates, >1×10(-5). About 70% of the risk is due to exposures occurring in homes. Outdoor sources contribute most to the risk of benzene, ethylbenzene and carbon tetrachloride, while indoor sources dominate for all other compounds. Chronic exposure limits are not exceeded for non-carcinogenic effects, except for formaldehyde. Risks are overestimated if variation is not accounted for. Sensitivity analyses demonstrate that the major contributors to total variance are range of inhalation rates, CPFs of formaldehyde, 1,4-dichlorobenzene, benzene and 1,3-butadiene, and indoor home concentrations of formaldehyde and benzene. Despite uncertainty, risks exceeding the acceptable benchmark of 1×10(-6) suggest actions to reduce exposures. Future efforts should be directed toward large-scale measurements of air pollutant concentrations, refinement of CPFs and investigation of population exposure parameters. The present study is a first effort to estimate carcinogenic and non-carcinogenic risks of inhalation exposure to HAPs for the large working populations of Chinese cites. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mercury Sources and Fate in the Gulf of Maine

PubMed Central

Sunderland, Elsie M.; Amirbahman, Aria; Burgess, Neil M.; Dalziel, John; Harding, Gareth; Jones, Stephen H.; Kamai, Elizabeth; Karagas, Margaret R.; Shi, Xun; Chen, Celia Y.

2012-01-01

Most human exposure to mercury (Hg) in the United States is from consuming marine fish and shellfish. The Gulf of Maine is a complex marine ecosystem comprised of twelve physioregions, including the Bay of Fundy, coastal shelf areas and deeper basins that contain highly productive fishing grounds. Here we review available data on spatial and temporal Hg trends to better understand the drivers of human and biological exposures. Atmospheric Hg deposition from U.S. and Canadian sources has declined since the mid-1990s in concert with emissions reductions but deposition from global sources has increased. Oceanographic circulation is the dominant source of total Hg inputs to the entire Gulf of Maine region (59%), followed by atmospheric deposition (28%), wastewater/industrial sources (8%), and rivers (5%). Resuspension of sediments increases MeHg inputs to overlying waters raising concerns about benthic trawling activities in shelf regions. In the near coastal areas, elevated sediment and mussel Hg levels are co-located in urban embayments and near large historical point sources. Temporal patterns in sentinel species (mussels and birds) have in some cases declined in response to localized point source mercury reductions but overall Hg trends do not show consistent declines. For example, levels of Hg have either declined or remained stable in eggs from four seabird species collected in the Bay of Fundy since 1972. Quantitatively linking Hg exposures from fish harvested from the Gulf of Maine to human health risks is challenging at this time because no data are available on the geographic origin of seafood consumed by coastal residents. In addition, there is virtually no information on Hg levels in commercial species for offshore regions of the Gulf of Maine where some of the most productive fisheries are located. Both of these data gaps should be priorities for future research. PMID:22572623

Measuring personal exposure from 900MHz mobile phone base stations in Australia and Belgium using a novel personal distributed exposimeter.

PubMed

Bhatt, Chhavi Raj; Thielens, Arno; Redmayne, Mary; Abramson, Michael J; Billah, Baki; Sim, Malcolm R; Vermeulen, Roel; Martens, Luc; Joseph, Wout; Benke, Geza

2016-01-01

The aims of this study were to: i) measure personal exposure in the Global System for Mobile communications (GSM) 900MHz downlink (DL) frequency band with two systems of exposimeters, a personal distributed exposimeter (PDE) and a pair of ExpoM-RFs, ii) compare the GSM 900MHz DL exposures across various microenvironments in Australia and Belgium, and iii) evaluate the correlation between the PDE and ExpoM-RFs measurements. Personal exposure data were collected using the PDE and two ExpoM-RFs simultaneously across 34 microenvironments (17 each in Australia and Belgium) located in urban, suburban and rural areas. Summary statistics of the electric field strengths (V/m) were computed and compared across similar microenvironments in Australia and Belgium. The personal exposures across urban microenvironments were higher than those in the rural or suburban microenvironments. Likewise, the exposure levels across the outdoor were higher than those for indoor microenvironments. The five highest median exposure levels were: city centre (0.248V/m), bus (0.124V/m), railway station (0.105V/m), mountain/forest (rural) (0.057V/m), and train (0.055V/m) [Australia]; and bicycle (urban) (0.238V/m), tram station (0.238V/m), city centre (0.156V/m), residential outdoor (urban) (0.139V/m) and park (0.124V/m) [Belgium]. Exposures in the GSM900 MHz frequency band across most of the microenvironments in Australia were significantly lower than the exposures across the microenvironments in Belgium. Overall correlations between the PDE and the ExpoM-RFs measurements were high. The measured exposure levels were far below the general public reference levels recommended in the guidelines of the ICNIRP and the ARPANSA. Copyright © 2016 Elsevier Ltd. All rights reserved.

Suburban Soils: Are they the answer in determining factors controlling non-point-source DOC and DON in urban surface waters?

NASA Astrophysics Data System (ADS)

Aitkenhead-Peterson, J. A.

2016-12-01

Generally the quality of urban streams has been attributed to storm water runoff and sewage effluent discharge. Recent work in the upper Trinity Basin downstream from the Dallas/Fort Worth metropolis, TX concluded that sewage effluent only contributed between 1 and 35% of DOC dependent upon the population of the watershed. Change from native to urban land use increased DOC exports to between 938 - 1840 kg km-2 yr-1relative to the 517 kg km-2 yr-1 expected from native land use. Where this excess DOC might come from in an urban ecosystem was addressed in a separate study examining water extractable DOC (WEDOC) and DON (WEDON) in soils of single-family home lawns in Chicago, IL, Frederick, MD, Bryan/College Station, TX and Galveston, TX. These cities were exposed to different sources of sodium. Time of exposure to sodium was considered on the assumption that as new sub-divisions are built, new soil or turfgrass sod is introduced to the site. Exposure times were 0-5, 6-10, 11-20, 21-30 and > 30 yr. Length of exposure time of the soil to the urban environment was significant among the four cities examined for DOC (p < 0.001), DON (p < 0.001), sodium adsorption ratio (p < 0.006) but not for sodium (p = 0.08) or exchangeable sodium percent (ESP) (p = 0.09). In all cities WEDON increased with urban exposure time and in all cities except Galveston WEDOC increased with urban exposure time. Sodium, regardless of its source, explained 60% of the variance in WEDOC and 54% of the variance in WEDON across all cities (n = 136). To determine what other factors might be involved in increasing WEDOC and WEDON losses from suburban soils, backward stepwise regression models were used. Across the four cities, time of urban exposure, soil saturated hydraulic conductivity (Ksat), NO3-N, NH4-N, S, PO4-P, Na, Cu, Ca, Fe and Zn produced a significant model for WEDOC (Adjusted r2 = 0.85; p < 0.001) and Ksat, pH, NH4-N, PO4-P, S, Alkalinity and Cu produced a significant model for WEDON (adjusted r2 = 0.81; p < 0.0001). Models for estimating WEDOC and WEDON were also produced for the individual cities. While sodium may be a player in the increasing DOC and DON observed in urban surface waters, more research is needed to determine the mechanisms of WEDOC and WEDON release from urban soils.

Nitrate leaching and nitrous oxide flux in urban forests and grasslands

Treesearch

Peter M. Groffman; Candiss O. Williams; Richard V. Pouyat; Lawrence E. Band; Ian D. Yesilonis

2009-01-01

Urban landscapes contain a mix of land-use types with different patterns of nitrogen (N) cycling and export. We measured nitrate (NO3-) leaching and soil:atmosphere nitrous oxide (N2O) flux in four urban grassland and eight forested long-term study plots in the Baltimore, Maryland metropolitan area....

Modeling the effects of urban vegetation on air pollution

Treesearch

David J. Nowak; Patrick J. McHale; Myriam Ibarra; Daniel Crane; Jack C. Stevens; Chris J. Luley

1998-01-01

Urban vegetation can directly and indirectly affect local and regional air quality by altering the urban atmospheric environment. Trees affect local air temperature by transpiring water through their leaves, by blocking solar radiation (tree shade), which reduces radiation absorption and heat storage by various anthropogenic surfaces (e.g., buildings, roads), and by...

Measurements of Carbon Dioxide and Carbon Monoxide at High Spatial and Temporal Resolution in an Urban Environment

NASA Astrophysics Data System (ADS)

Rella, C.; Jacobson, G. A.; Crosson, E.

2011-12-01

The ability to take inventory of critical greenhouse gases such as carbon dioxide and methane and quantify their sources and sinks is essential for understanding the atmospheric drivers to global climate change. "Top down" inversion measurements and models are used to quantify net carbon fluxes into the atmosphere. The overall carbon fluxes are determined by combining remote measurements of carbon dioxide concentrations with complex atmospheric transport models, and these emissions measurements are compared to "bottoms-up" predictions based on detailed inventories of the sources and sinks of carbon, both anthropogenic and biogenic in nature. At smaller distance scales, such as that of a city or even smaller, the basic framework underpinning the inversion modeling technique begins to break down: atmospheric transport models, which are well understood at a length scale of 100 km, work poorly or not at all at a 100m distance scale. Furthermore, the variability of the emissions sources in space (e.g., factories, highways, residences) and time (rush hours, factory shifts and shutdowns, residential energy usage variability during the day and over the year) complicate the interpretation of the measured signals. In this paper we present detailed, high spatial- and temporal-resolution greenhouse gas measurements in Silicon Valley, CA. The results of two experimental campaigns are presented: a 10m urban 'tower' and ground-based mobile mapping measurements. In both campaigns, real-time carbon dioxide data are combined with real-time carbon monoxide measurements to partition the observed CO2 concentrations between anthropogenic and biogenic sources . The urban tower measurements are made continuously over a period of many weeks. The mobile maps of the vicinity of the urban tower are taken repeatedly over a period of several days, and at different times of the day and under different atmospheric conditions, to assess the robustness and repeatability of the maps. Initial interpretation of the data is provided, using simple atmospheric models. These methods show great promise for quantifying and partitioning emissions in an urban setting with unprecedented detail.

Comparison of Effect of Two-Hour Exposure to Forest and Urban Environments on Cytokine, Anti-Oxidant, and Stress Levels in Young Adults.

PubMed

Im, Su Geun; Choi, Han; Jeon, Yo-Han; Song, Min-Kyu; Kim, Won; Woo, Jong-Min

2016-06-23

The purpose of this study was to investigate the effect of two-hour exposure to a forest environment on cytokine, anti-oxidant and stress levels among university students and to compare the results to those measured in urban environments. Forty-one subjects were recruited. For our crossover design, subjects were divided into two groups based on similar demographic characteristics. Group A remained in the urban environment and was asked to perform regular breathing for 2 h. Blood samples were collected and the serum levels of cytokines including interleukin-6 (IL-6), IL-8, tumor necrosis factor-α (TNF-α), and glutathione peroxidase (GPx) were examined. Subjects were moved to a small town in a rural area for an equal amount of time to exclude carryover effects, and then remained for another 2 h in a forest environment. The second set of blood samples was collected to assess the effect of exposure to the forest environment. Using the same method, Group B was first exposed to the forest environment, followed by exposure to the urban environment. Blood samples collected after the subjects were exposed to the forest environment showed significantly lower levels of IL-8 and TNF-α compared to those in samples collected after urban environment exposure (10.76 vs. 9.21, t = 4.559, p < 0.001, and 0.97 vs. 0.87, t = 4.130, p < 0.001). The GPx concentration increased significantly after exposure to the forest environment (LnGPx = 5.09 vs. LnGPx = 5.21, t = -2.039, p < 0.05).

Characteristics of urban-ecosystem atmosphere fluxes of CO2, CH4, N2O, and et over Denver, Colorado

USGS Publications Warehouse

Anderson, D.E.; Alvarez, C.; Thienelt, T.

2004-01-01

The characteristics of urban ecosystems fluxes of carbon dioxide, methane, nitrous oxide, and evapotranspiration (ET) over Denver, Colorado were discussed. These atmospheric fluxes were measured using a methodology that included a combination of eddy covariance sensors at two levels on a tall tower and chamber measurements at 33 locations on the soil surface. There was both strong temporal and spatial heterogeneity of fluxes owing to characteristics of natural and anthropogenic ecosystem components. Although the urban ecosystem was a net carbon dioxide source, tower-based eddy covariance measurements showed it to be a net vegetative sink during the majority of mid-say summer hours.

New Particle Formation in an Urban Atmosphere: The Role of Various Ingredients Investigated in the CLOUD Chamber

NASA Astrophysics Data System (ADS)

Baltensperger, U.; Xiao, M.; Hoyle, C.; Dada, L.; Garmash, O.; Stolzenburg, D.; Molteni, U.; Lehtipalo, K.; El-Haddad, I.; Dommen, J.

2017-12-01

Atmospheric aerosols play an important role on climate via aerosol-radiation interaction and aerosol-cloud interaction. The latter is strongly influenced by new particle formation (NPF). The physical and chemical mechanisms behind the NPF process are still under investigation. Great advancements were made in resolving chemical and physical mechanisms of NPF with a series of experiments conducted at the CLOUD (Cosmics Leaving Outdoor Droplets) chamber facility at CERN (Geneva, Switzerland), including binary nucleation of sulfuric acid - water, ternary nucleation of sulfuric acid - water with ammonia or dimethylamine as well as oxidation products (highly oxygenated molecules, HOMs) from biogenic precursors with and without the presence of sulfuric acid. Here, we investigate possible NPF mechanisms in urban atmospheres, where large populations are exposed to high aerosol concentrations; these mechanisms are still missing and are urgently needed. Urban atmospheres are highly polluted with high concentrations of SO2, ammonia, NOx and volatile organic vapors from anthropogenic activity as well as with high particle concentrations, which provide a high condensation sink for condensable gases. Aromatic hydrocarbons from industrial activities, traffic and residential combustion are present at high concentrations and contribute significantly to photochemical smog in the urban environment.The experiments were conducted at the CLOUD chamber facility during the CLOUD11 campaign in fall 2016. Three aromatic hydrocarbons were selected: toluene, 1,2,4-trimethylbenzene (1,2,4-TMB) and naphthalene (NPT). Experiments were also conducted with mixtures of the three aromatic hydrocarbons to better represent the urban atmosphere. All the experiments were conducted in the presence of sulfuric acid concentrations with or without the addition of ammonia and NOx. New particle formation rates and early growth rates derived for each precursor and their mixture, together with sulfuric acid and with or without the addition of ammonia and NOx will be reported.

Students 'Weigh' Atmospheric Pollution.

ERIC Educational Resources Information Center

Caporaloni, Marina

1998-01-01

Describes a procedure developed by students that measures the mass concentration of particles in a polluted urban atmosphere. Uses a portable fan and filters of various materials. Compares students' data with official data. (DDR)

Assessing levels and seasonal variations of current-use pesticides (CUPs) in the Tuscan atmosphere, Italy, using polyurethane foam disks (PUF) passive air samplers.

PubMed

Estellano, Victor H; Pozo, Karla; Efstathiou, Christos; Pozo, Katerine; Corsolini, Simonetta; Focardi, Silvano

2015-10-01

Polyurethane foam disks (PUF) passive air samplers (PAS) were deployed over 4 sampling periods of 3-5-months (≥ 1 year) at ten urban and rural locations throughout the Tuscany Region. The purpose was to assess the occurrence and seasonal variations of ten current-use pesticides (CUPs). PUF disk extracts were analyzed using GC-MS. The organophosphates insecticides; chlorpyrifos (3-580 pg m(-3)) and chlorpyrifos-methyl (below detection limit - to 570 pg m(-3)) presented the highest levels in air, and showed seasonal fluctuation coinciding with the growing seasons. The relative proportion urban/(urban + rural) ranged from 0.4 to 0.7 showing no differences between urban and rural concentrations. Air back trajectories analysis showed air masses passing over agricultural fields and potentially enhancing the drift of pesticides into the urban sites. This study represents the first information regarding CUPs in the atmosphere of Tuscany region using PAS-PUF disk. Copyright © 2015 Elsevier Ltd. All rights reserved.

Persistent toxic substance inputs to the river Seine basin (France) via atmospheric deposition and urban sludge application.

PubMed

Blanchard, M; Teil, M-J; Guigon, E; Larcher-Tiphagne, K; Ollivon, D; Garban, B; Chevreuil, M

2007-04-01

Paris constitutes a major direct and indirect source of persistent toxic substances (PTS) to the river Seine, its tributaries and its basin, by atmospheric depositions and sewage sludge land-filling. The contaminant cycle and transfer pathways were investigated from 1999 to 2003 at local and inter regional scales in order to determine the respective importance of the main input and diffusion processes (wastewater, rainwater and runoff) from urban to rural areas. Paris constitutes an atmospheric emission hot spot for PAHs and PCBs. For example, for 2002, atmospheric concentrations ranged from 0.5 to 3 ng m(-3) for PAHs (Sigma 6 WHO) and from 0.06 to 0.69 ng m(-3) for PCBs (Sigma 7, EEC) and concentrations in bulk deposition ranged from 6.6 to 647 ng L(-1) for PAHs (Sigma 14) and from 0.6 to 8.1 ng L(-1) for PCBs. At Paris, annual atmospheric deposition inputs of PAHs (Sigma 6) and PCBs (Sigma 7) reached 104 g km(-2) and 35 g km(-2), respectively. PAHs followed a marked seasonal cycle in relation with winter domestic heating and bulk deposition concentrations were 5 to 15 times lower in remote areas. No seasonal cycle was observed for PCBs which varied little according to the area considered. PCB deposition fluxes were ruled by the rainfall amount, while for PAHs, the fluxes depended on local anthropogenic characteristics. At the scale of the Seine-Aval treatment plant comparison of annual inputs of PTS in wet period indicated that PCBs essentially come from atmospheric sources whereas PAHs are derived from both atmospheric and urban runoff sources. At the scale of the sub-basin, atmospheric inputs to the soil (Sigma 3 PAHs: 14-25 g km(-2), Sigma 7 PCBs: 5.6-25 g km(-2)) represent the prevailing source for PAHs and PCBs, as compared to that from the disposal of urban sludge on agricultural plots (Sigma 3 PAHs: 3-8 g km(-2), Sigma 7 PCBs: 0.5-2 g km(-2)).

Variability in the combustion-derived fraction of urban humidity in Salt Lake City winter estimated from stable water vapor isotopes and its relationship to atmospheric stability and inversion structure

NASA Astrophysics Data System (ADS)

Fiorella, R.; Bares, R.; Lin, J. C.; Strong, C.; Bowen, G. J.

2017-12-01

Water released from the combustion of fossil fuels, while a negligible part of the global hydrological cycle, may be a significant contributor to urban humidity as fossil fuel emissions are strongly concentrated in space and time. The fraction of urban humidity comprised of combustion-derived vapor (CDV) cannot be observed through humidity measurements alone. However, the distinct stable isotopic composition of CDV, which arises from the reaction of 18O-enriched atmospheric O2 with 2H-depleted organic molecules, represents a promising method to apportion observed humidity between CDV and advected vapor. We apply stable water vapor isotopes to investigate variability in CDV amount and its relationship to atmospheric conditions in Salt Lake City, Utah. The Salt Lake Valley experiences several periods of atmospheric stratification during winter known as cold air pools, during which concentrations of CDV and pollutants can be markedly elevated due to reduced atmospheric mixing. Therefore, the SLV during winter is an ideal place to investigate variability in CDV fraction across a spectrum of boundary layer conditions, ranging from well-mixed to very stable. We present water vapor isotope data from four winters (2013-2017) from the top of a 30 m building on the University of Utah (U of U) Campus. Additionally, we present water vapor isotope data from the summit of Hidden Peak from the 2016-2017 winter, 25 km SE and 2000 m above the U of U site. The Hidden Peak site is consistently above the cold air pool emplaced in the SLV during stable events. We find the expression of the CDV signal in the valley is related to the atmospheric structure of the cold air pools in the SLV, and that the fraction of CDV inferred in the valley is likely related to the mixing height within the cold air pool. Furthermore, we find that patterns between the Hidden Peak and U of U sites during inversion events may record the large-scale atmospheric dynamics promoting emplacement of the cold air pool in the SLV. Further refinements of CDV estimation through stable isotope methods will bring improved mechanistic understanding of the role of CDV in the urban hydrological cycle and improve model simulations of urban environments.

Gaseous VOCs rapidly modify particulate matter and its biological effects - Part 2: Complex urban VOCs and model PM

NASA Astrophysics Data System (ADS)

Ebersviller, S.; Lichtveld, K.; Sexton, K. G.; Zavala, J.; Lin, Y.-H.; Jaspers, I.; Jeffries, H. E.

2012-03-01

This is the second study in a three-part study designed to demonstrate dynamic entanglements among gaseous organic compounds (VOCs), particulate matter (PM), and their subsequent potential biological effects. We study these entanglements in increasingly complex VOC and PM mixtures in urban-like conditions in a large outdoor chamber, both in the dark and in sunlight. To the traditional chemical and physical characterizations of gas and PM, we added new measurements of gas-only- and PM-only-biological effects, using cultured human lung cells as model living receptors. These biological effects are assessed here as increases in cellular damage or expressed irritation (i.e., cellular toxic effects) from cells exposed to chamber air relative to cells exposed to clean air. Our exposure systems permit side-by-side, gas-only- and PM-only-exposures from the same air stream containing both gases and PM in equilibria, i.e., there are no extractive operations prior to cell exposure for either gases or PM. In Part 1 (Ebersviller et al., 2012a), we demonstrated the existence of PM "effect modification" (NAS, 2004) for the case of a single gas-phase toxicant and an inherently non-toxic PM (mineral oil aerosol, MOA). That is, in the presence of the single gas-phase toxicant in the dark, the initially non-toxic PM became toxic to lung cells in the PM-only-biological exposure system. In this Part 2 study, we used sunlit-reactive systems to create a large variety of gas-phase toxicants from a complex mixture of oxides of nitrogen and 54 VOCs representative of those measured in US city air. In these mostly day-long experiments, we have designated the period in the dark just after injection (but before sunrise) as the "Fresh" condition and the period in the dark after sunset as the "Aged" condition. These two conditions were used to expose cells and to collect chemical characterization samples. We used the same inherently non-toxic PM from the Part 1 study as the target PM for "effect modification". Fortunately, in the absence of "seed particles", the complex highly-reactive VOC system used does not create any secondary aerosol in situ. All PM present in these tests were, therefore, introduced by injection of MOA to serve as PM-to-be-modified by the gaseous environment. PM addition was only done during dark periods, either before or after the daylight period. The purpose of this design is to test if a non-toxic PM becomes toxic in initially unreacted ("Fresh"), or in reacted ("Aged") complex VOC conditions. To have a complete design, we also tested the effects of clean air and the same VOC conditions, but without introducing any PM. Thus, there were six exposure treatment conditions that were evaluated with the side-by-side, gas-only- and PM-only-effects exposure systems; five separate chamber experiments were performed: two with clean air and three with the complex VOC/NOx mixture. For all of these experiments and exposures, chemical composition data and matching biological effects results for two end-points were compared. Chemical measurements demonstrate the temporal evolution of oxidized species, with a corresponding increase in toxicity observed from exposed cells. The largest increase in gas-phase toxicity was observed in the two "Aged" VOC exposures. The largest increase in particle-phase toxicity was observed in the "Aged" VOC exposure with the addition of PM after sunset. These results are a clear demonstration that the findings from Part 1 can be extended to the complex urban oxidized environment. This further demonstrates that the atmosphere itself cannot be ignored as a source of toxic species when establishing the risks associated with exposure to PM. Because gases and PM are transported and deposited differently within the atmosphere and lungs, these results have significant consequences. In the next (and final) part of the study, testing is further applied to systems with real diesel exhaust, including primary PM from a vehicle operated with different types of diesel fuel.

Gaseous VOCs rapidly modify particulate matter and its biological effects - Part 2: Complex urban VOCs and model PM

NASA Astrophysics Data System (ADS)

Ebersviller, S.; Lichtveld, K.; Sexton, K. G.; Zavala, J.; Lin, Y.-H.; Jaspers, I.; Jeffries, H. E.

2012-12-01

This is the second study in a three-part study designed to demonstrate dynamic entanglements among gaseous organic compounds (VOCs), particulate matter (PM), and their subsequent potential biological effects. We study these entanglements in increasingly complex VOC and PM mixtures in urban-like conditions in a large outdoor chamber, both in the dark and in sunlight. To the traditional chemical and physical characterizations of gas and PM, we added new measurements of gas-only- and PM-only-biological effects, using cultured human lung cells as model living receptors. These biological effects are assessed here as increases in cellular damage or expressed irritation (i.e., cellular toxic effects) from cells exposed to chamber air relative to cells exposed to clean air. Our exposure systems permit side-by-side, gas-only- and PM-only-exposures from the same air stream containing both gases and PM in equilibria, i.e., there are no extractive operations prior to cell exposure for either gases or PM. In Part 1 (Ebersviller et al., 2012a), we demonstrated the existence of PM "effect modification" (NAS, 2004) for the case of a single gas-phase toxicant and an inherently non-toxic PM (mineral oil aerosol, MOA). That is, in the presence of the single gas-phase toxicant in the dark, the initially non-toxic PM became toxic to lung cells in the PM-only-biological exposure system. In this Part 2 study, we used sunlit-reactive systems to create a large variety of gas-phase toxicants from a complex mixture of oxides of nitrogen and 54 VOCs representative of those measured in US city air. In these mostly day-long experiments, we have designated the period in the dark just after injection (but before sunrise) as the "Fresh" condition and the period in the dark after sunset as the "Aged" condition. These two conditions were used to expose cells and to collect chemical characterization samples. We used the same inherently non-toxic PM from the Part 1 study as the target PM for "effect modification". Fortunately, in the absence of "seed particles", the complex highly-reactive VOC system used does not create any secondary aerosol in situ. All PM present in these tests were, therefore, introduced by injection of MOA to serve as PM-to-be-modified by the gaseous environment. PM addition was only done during dark periods, either before or after the daylight period. The purpose of this design is to test if a non-toxic PM becomes toxic in initially unreacted ("Fresh"), or in reacted ("Aged") complex VOC conditions. To have a complete design, we also tested the effects of clean air and the same VOC conditions, but without introducing any PM. Thus, there were six exposure treatment conditions that were evaluated with the side-by-side, gas-only- and PM-only-effects exposure systems; five separate chamber experiments were performed: two with clean air and three with the complex VOC/NOx mixture. For all of these experiments and exposures, chemical composition data and matching biological effects results for two end-points were compared. Chemical measurements demonstrate the temporal evolution of oxidized species, with a corresponding increase in toxicity observed from exposed cells. The largest increase in gas-phase toxicity was observed in the two "Aged" VOC exposures. The largest increase in particle-phase toxicity was observed in the "Aged" VOC exposure with the addition of PM after sunset. These results are a clear demonstration that the findings from Part 1 can be extended to the complex urban oxidized environment. This further demonstrates that the atmosphere itself cannot be ignored as a source of toxic species when establishing the risks associated with exposure to PM. Because gases and PM are transported and deposited differently within the atmosphere and lungs, these results have significant consequences. In the next (and final) part of the study, testing is further applied to systems with real diesel exhaust, including primary PM from a vehicle operated with different types of diesel fuel.

Simulation of trace metals and PAH atmospheric pollution over Greater Paris: Concentrations and deposition on urban surfaces

NASA Astrophysics Data System (ADS)

Thouron, L.; Seigneur, C.; Kim, Y.; Legorgeu, C.; Roustan, Y.; Bruge, B.

2017-10-01

Urban areas can be subject not only to poor air quality, but also to contamination of other environmental media by air pollutants. Here, we address the potential transfer of selected air pollutants (two metals and three PAH) to urban surfaces. To that end, we simulate meteorology and air pollution from Europe to a Paris suburban neighborhood, using a four-level one-way nesting approach. The meteorological and air quality simulations use urban canopy sub-models in order to better represent the effect of the urban morphology on the air flow, atmospheric dispersion, and deposition of air pollutants to urban surfaces. This modeling approach allows us to distinguish air pollutant deposition among various urban surfaces (roofs, roads, and walls). Meteorological model performance is satisfactory, showing improved results compared to earlier simulations, although precipitation amounts are underestimated. Concentration simulation results are also satisfactory for both metals, with a fractional bias <0.5. Concentrations of benzo[a]pyrene are overestimated, probably because continental emissions may be overestimated. Concentrations of benzo[b]fluoranthene and indeno[1,2,3,cd]pyrene are underestimated, in part because of null boundary conditions. PAH deposition fluxes are consistent with earlier measurements obtained in the Greater Paris region. The model simulation results suggest that both wet and dry deposition processes need to be considered when estimating the transfer of air pollutants to other environmental media. Dry deposition fluxes to various urban surfaces are mostly uniform for PAH, which are entirely present in fine particles. However, there is significantly less wall deposition compared to deposition to roofs and roads for trace metals, due to their coarse fraction. Meteorology, particle size distribution, and urban morphology are all important factors affecting air pollutant deposition. Future work should focus on the collection of data suitable to evaluate the performance of atmospheric models for both wet and dry deposition with fine spatial resolution.

Exposure to violence and parenting as mediators between poverty and psychological symptoms in urban African American adolescents.

PubMed

Grant, Kathryn E; McCormick, Anthony; Poindexter, LaShaunda; Simpkins, Tandra; Janda, Cassandra M; Thomas, Kina J; Campbell, Amanda; Carleton, Russell; Taylor, Jeremy

2005-08-01

The present study builds on past research that has found support for a conceptual model in which poverty is linked with adolescent psychological symptoms through economic stressors and impaired parenting. The present study examined this model in a sample of urban African American mothers and their adolescent children. In addition, an alternative hypothesis was examined: that exposure to community violence mediates the relation between poverty and psychological symptoms in urban youth. Limited support was found for a model in which poverty is linked with internalizing symptoms through exposure to community violence and with externalizing symptoms through economic stressors and inconsistent discipline. Interpretations, limitations, and directions for future research are outlined.

A Heat Vulnerability Index: Spatial Patterns of Exposure, Sensitivity and Adaptive Capacity for Santiago de Chile.

PubMed

Inostroza, Luis; Palme, Massimo; de la Barrera, Francisco

2016-01-01

Climate change will worsen the high levels of urban vulnerability in Latin American cities due to specific environmental stressors. Some impacts of climate change, such as high temperatures in urban environments, have not yet been addressed through adaptation strategies, which are based on poorly supported data. These impacts remain outside the scope of urban planning. New spatially explicit approaches that identify highly vulnerable urban areas and include specific adaptation requirements are needed in current urban planning practices to cope with heat hazards. In this paper, a heat vulnerability index is proposed for Santiago, Chile. The index was created using a GIS-based spatial information system and was constructed from spatially explicit indexes for exposure, sensitivity and adaptive capacity levels derived from remote sensing data and socio-economic information assessed via principal component analysis (PCA). The objective of this study is to determine the levels of heat vulnerability at local scales by providing insights into these indexes at the intra city scale. The results reveal a spatial pattern of heat vulnerability with strong variations among individual spatial indexes. While exposure and adaptive capacities depict a clear spatial pattern, sensitivity follows a complex spatial distribution. These conditions change when examining PCA results, showing that sensitivity is more robust than exposure and adaptive capacity. These indexes can be used both for urban planning purposes and for proposing specific policies and measures that can help minimize heat hazards in highly dynamic urban areas. The proposed methodology can be applied to other Latin American cities to support policy making.

A Heat Vulnerability Index: Spatial Patterns of Exposure, Sensitivity and Adaptive Capacity for Santiago de Chile

PubMed Central

Palme, Massimo; de la Barrera, Francisco

2016-01-01

Climate change will worsen the high levels of urban vulnerability in Latin American cities due to specific environmental stressors. Some impacts of climate change, such as high temperatures in urban environments, have not yet been addressed through adaptation strategies, which are based on poorly supported data. These impacts remain outside the scope of urban planning. New spatially explicit approaches that identify highly vulnerable urban areas and include specific adaptation requirements are needed in current urban planning practices to cope with heat hazards. In this paper, a heat vulnerability index is proposed for Santiago, Chile. The index was created using a GIS-based spatial information system and was constructed from spatially explicit indexes for exposure, sensitivity and adaptive capacity levels derived from remote sensing data and socio-economic information assessed via principal component analysis (PCA). The objective of this study is to determine the levels of heat vulnerability at local scales by providing insights into these indexes at the intra city scale. The results reveal a spatial pattern of heat vulnerability with strong variations among individual spatial indexes. While exposure and adaptive capacities depict a clear spatial pattern, sensitivity follows a complex spatial distribution. These conditions change when examining PCA results, showing that sensitivity is more robust than exposure and adaptive capacity. These indexes can be used both for urban planning purposes and for proposing specific policies and measures that can help minimize heat hazards in highly dynamic urban areas. The proposed methodology can be applied to other Latin American cities to support policy making. PMID:27606592

[Characteristics of CO2 flux before and in the heating period at urban complex underlying surface area].

PubMed

Jia, Qing-yu; Zhou, Guang-sheng; Wang, Yu; Liu, Xiao-mei

2010-04-01

Urban areas were significant contributors to global carbon dioxide emissions. The eddy covariance (EC) was used to measure carbon dioxide (CO2) concentration and flux data at urban area in Shenyang. This research analyzed the characteristics of atmospheric CO2 concentration and flux in October 2008 to November 2008 period before and in the heating period. The results showed that the daily variation of CO2 concentration was two-peak curve. The first peak time appeared as same as sunrise time, while the second peak time impacted by vehicles and heating. The result of CO2 flux showed that urban atmospheric CO2 was net emissions, vegetation photosynthesis absorbed CO2 of traffic, the CO2 flux peak appeared at 17:15-18:15 in the heating period, CO2 emission increased 29.37 g x (m2 x d)(-1) in the heating period than that before the heating period; there was corresponding relationship between CO2 flux and the time when temperature peak and sensible heating flux (Hc) turn positive. The results also indicated that atmospheric CO2 concentration and its flux were affected seriously by both wind direction and carbon sources.

The effect of anthropogenic activity on BTEX, NO2, SO2, and CO concentrations in urban air of the spa city of Sopot and medium-industrialized city of Tczew located in North Poland.

PubMed

Marć, Mariusz; Bielawska, Michalina; Simeonov, Vasil; Namieśnik, Jacek; Zabiegała, Bożena

2016-05-01

The major goal of the present study is to compare the air quality of two urban locations situated in Northern Poland - the spa City of Sopot and the medium-industrialized city of Tczew using chemometric methods. As a criterion for the assessment of atmospheric air quality, measurements of benzene, toluene, ethylbenzene and total xylenes were used (collected from atmospheric air using diffusion-type passive samplers) as well as measurements of inorganic compounds - CO, NO2 and SO2, which were subject to routine control and determined by means of automatic analysers. Studies related to determination of defined chemical compounds in the urban air in the monitored area were performed from January 2013 to December 2014. By interpreting the results obtained and using basic multivariate statistical tools (cluster analysis and principal components analysis), major sources of emissions of determined pollutants in the air in urbanized areas were defined. The study also shows the potential influence of the sea breeze on concentrations of chemical compounds in the atmospheric air in the spa city of Sopot. Copyright © 2016 Elsevier Inc. All rights reserved.

Scale effects in wind tunnel modeling of an urban atmospheric boundary layer

NASA Astrophysics Data System (ADS)

Kozmar, Hrvoje

2010-03-01

Precise urban atmospheric boundary layer (ABL) wind tunnel simulations are essential for a wide variety of atmospheric studies in built-up environments including wind loading of structures and air pollutant dispersion. One of key issues in addressing these problems is a proper choice of simulation length scale. In this study, an urban ABL was reproduced in a boundary layer wind tunnel at different scales to study possible scale effects. Two full-depth simulations and one part-depth simulation were carried out using castellated barrier wall, vortex generators, and a fetch of roughness elements. Redesigned “Counihan” vortex generators were employed in the part-depth ABL simulation. A hot-wire anemometry system was used to measure mean velocity and velocity fluctuations. Experimental results are presented as mean velocity, turbulence intensity, Reynolds stress, integral length scale of turbulence, and power spectral density of velocity fluctuations. Results suggest that variations in length-scale factor do not influence the generated ABL models when using similarity criteria applied in this study. Part-depth ABL simulation compares well with two full-depth ABL simulations indicating the truncated vortex generators developed for this study can be successfully employed in urban ABL part-depth simulations.

Relative impact of on-road vehicular and point-source industrial emissions of air pollutants in a medium-sized Andean city

NASA Astrophysics Data System (ADS)

González, C. M.; Gómez, C. D.; Rojas, N. Y.; Acevedo, H.; Aristizábal, B. H.

2017-03-01

Cities in emerging countries are facing a fast growth and urbanization; however, the study of air pollutant emissions and its dynamics is scarce, making their populations vulnerable to potential effects of air pollution. This situation is critical in medium-sized urban areas built along the tropical Andean mountains. This work assesses the contribution of on-road vehicular and point-source industrial activities in the medium-sized Andean city of Manizales, Colombia. Annual fluxes of criteria pollutants, NMVOC, and greenhouse gases were estimated. Emissions were dominated by vehicular activity, with more than 90% of total estimated releases for the majority of air pollutants. On-road vehicular emissions for CO (43.4 Gg/yr) and NMVOC (9.6 Gg/yr) were mainly associated with the use of motorcycles (50% and 81% of total CO and NMVOC emissions respectively). Public transit buses were the main source of PM10 (47%) and NOx (48%). The per-capita emission index was significantly higher in Manizales than in other medium-sized cities, especially for NMVOC, CO, NOx and CO2. The unique mountainous terrain of Andean cities suggest that a methodology based on VSP model could give more realistic emission estimates, with additional model components that include slope and acceleration. Food and beverage facilities were the main contributors of point-source industrial emissions for PM10 (63%), SOx (55%) and NOx (45%), whereas scrap metal recycling had high emissions of CO (73%) and NMVOC (47%). Results provide the baseline for ongoing research in atmospheric modeling and urban air quality, in order to improve the understanding of air pollutant fluxes, transport and transformation in the atmosphere. In addition, this emission inventory could be used as a tool to identify areas of public health exposure and provide information for future decision makers.

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

NASA Astrophysics Data System (ADS)

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

2014-01-01

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

Geochemical Legacies and the Future Health of Cities: An Analysis of two Neurotoxins in Urban Soils

NASA Astrophysics Data System (ADS)

Filippelli, G. M.; Risch, M.

2015-12-01

The past and future of cities are inextricably linked, a linkage that can be seen clearly in the long-term impacts of urban geochemical legacies. As loci of population as well as the means of employment and industry to support these populations, cities have a long history of co-locating contaminating practices and people, sometimes with negative implications for human health. Working at the intersection between geochemical processes, communities, and human health is critical to grapple with environmental legacies and to support healthy, sustainable, and growing urban populations. An emerging area of environmental health research is to understand the impacts of chronic exposures and exposure mixtures—these impacts are very poorly studied, yet have materialized as perhaps the greatest threat to large-scale population health. Acute exposure to lead (Pb), a powerful neurotoxin to which children are particularly susceptible, has largely been eliminated in the U.S. and other countries through policy-based restrictions on leaded gasoline and lead-based paints. But these legacy Pb sources are still around in the form of surface soil Pb contamination, a common problem in cities and one that has only recently emerged as a pernicious and widespread chronic exposure mechanism in cities. Some urban soils are also contaminated with another neurotoxin, mercury (Hg), although very little work has been done to understand human exposures to low levels of this element in soils. The most documented human exposure to Hg is through fish consumption, so eating fish caught in urban areas presents risks for above average dietary Hg exposure. The potential double impact of chronic exposure to these two neurotoxins is pronounced in cities. Many aspects of the dose-response curves for individual elements and mixtures are poorly understood, especially at lower levels, leaving unanswered several interesting and provocative questions about environmental impacts on neurological and developmental disorders.

Urban and Transport Planning Related Exposures and Mortality: A Health Impact Assessment for Cities

PubMed Central

Mueller, Natalie; Rojas-Rueda, David; Basagaña, Xavier; Cirach, Marta; Cole-Hunter, Tom; Dadvand, Payam; Donaire-Gonzalez, David; Foraster, Maria; Gascon, Mireia; Martinez, David; Tonne, Cathryn; Triguero-Mas, Margarita; Valentín, Antònia; Nieuwenhuijsen, Mark

2016-01-01

Background: By 2050, nearly 70% of the global population is projected to live in urban areas. Because the environments we inhabit affect our health, urban and transport designs that promote healthy living are needed. Objective: We estimated the number of premature deaths preventable under compliance with international exposure recommendations for physical activity (PA), air pollution, noise, heat, and access to green spaces. Methods: We developed and applied the Urban and TranspOrt Planning Health Impact Assessment (UTOPHIA) tool to Barcelona, Spain. Exposure estimates and mortality data were available for 1,357,361 residents. We compared recommended with current exposure levels. We quantified the associations between exposures and mortality and calculated population attributable fractions to estimate the number of premature deaths preventable. We also modeled life-expectancy and economic impacts. Results: We estimated that annually, nearly 20% of mortality could be prevented if international recommendations for performance of PA; exposure to air pollution, noise, and heat; and access to green space were followed. Estimations showed that the greatest portion of preventable deaths was attributable to increases in PA, followed by reductions of exposure to air pollution, traffic noise, and heat. Access to green spaces had smaller effects on mortality. Compliance was estimated to increase the average life expectancy by 360 (95% CI: 219, 493) days and result in economic savings of 9.3 (95% CI: 4.9, 13.2) billion EUR/year. Conclusions: PA factors and environmental exposures can be modified by changes in urban and transport planning. We emphasize the need for a) the reduction of motorized traffic through the promotion of active and public transport and b) the provision of green infrastructure, both of which are suggested to provide opportunities for PA and for mitigation of air pollution, noise, and heat. Citation: Mueller N, Rojas-Rueda D, Basagaña X, Cirach M, Cole-Hunter T, Dadvand P, Donaire-Gonzalez D, Foraster M, Gascon M, Martinez D, Tonne C, Triguero-Mas M, Valentín A, Nieuwenhuijsen M. 2017. Urban and transport planning related exposures and mortality: a health impact assessment for cities. Environ Health Perspect 125:89–96; http://dx.doi.org/10.1289/EHP220 PMID:27346385

REDUCTIONS IN HUMAN BENZENE EXPOSURE IN THE CALIFORNIA SOUTH COAST AIR BASIN. (R827352C004)

EPA Science Inventory

Benzene typically contributes a significant fraction of the human cancer risk associated with exposure to urban air pollutants. In recent years, concentrations of benzene in ambient air have declined in many urban areas due to the use of reformulated gasolines, lower vehicle e...

Gender Differences in the Longitudinal Impact of Exposure to Violence on Mental Health in Urban Youth

ERIC Educational Resources Information Center

Zona, Kate; Milan, Stephanie

2011-01-01

There is evidence of gender differences in psychopathology during adolescence, but little research has investigated gender differences in trauma-related symptoms. Exposure to violence is a commonly experienced potentially traumatic event among urban adolescents, and the few studies examining gender differences in its mental health impact have…

Reducing health risks from indoor exposures in rapidly developing urban China.

PubMed

Zhang, Yinping; Mo, Jinhan; Weschler, Charles J

2013-07-01

Over the past two decades there has been a large migration of China's population from rural to urban regions. At the same time, residences in cities have changed in character from single-story or low-rise buildings to high-rise structures constructed and furnished with many synthetic materials. As a consequence, indoor exposures (to pollutants with outdoor and indoor sources) have changed significantly. We briefly discuss the inferred impact that urbanization and modernization have had on indoor exposures and public health in China. We argue that growing adverse health costs associated with these changes are not inevitable, and we present steps that could be taken to reduce indoor exposures to harmful pollutants. As documented by China's Ministry of Health, there have been significant increases in morbidity and mortality among urban residents over the past 20 years. Evidence suggests that the population's exposure to air pollutants has contributed to increases in lung cancer, cardiovascular disease, pulmonary disease, and birth defects. Whether a pollutant has an outdoor or an indoor source, most exposure to the pollutant occurs indoors. Going forward, indoor exposures can be reduced by limiting the ingress of outdoor pollutants (while providing adequate ventilation with clean air), minimizing indoor sources of pollutants, updating government policies related to indoor pollution, and addressing indoor air quality during a building's initial design. Taking the suggested steps could lead to significant reductions in morbidity and mortality, greatly reducing the societal costs associated with pollutant derived ill health.

Exposure Assessment of Polycyclic Aromatic Hydrocarbon (PAHs) in Childcare Centers of Muang, Nakhon Ratchasima

NASA Astrophysics Data System (ADS)

Jitlada, C.; Pentamwa, P.

2018-03-01

This study aims to characterize airborne polycyclic aromatic hydrocarbons (PAHs) as of particulate and vapor phases variation. The samples were collected from the childcare centers where divided into urban and rural areas in Nakhon Ratchasima Province of Thailand. The airborne samples were collected from five childcare centers during the dry season in the year 2017. The PAHs species were determined by the gas chromatography and mass spectroscopy (GS/MS) method. Results show that the total concentrations of PAHs were higher than vapor phase that both similar in urban area and rural area. The dominant PAHs compounds of both urban and rural areas were benzo(a)pyrene, benzo(a,h)anthracene and indeno(1,2,3-cd)pyrene, respectively. Furthermore, the concentrations of PAHs in municipality (urban) childcare centers were higher than rural childcare centers area of Nakhon Ratchasima province. The risks associated with exposure to PAHs were evaluated using the TEF approach. The estimated value of lifetime lung cancer risks children in urban were significantly (p < 0.05) 2 times of children in rural, thus demonstrating that exposure to PAHs at levels found at urban site may be cause potential health risks.

Updating about reductions of air and blood lead concentrations in Turin, Italy, following reductions in the lead content of gasoline.

PubMed

Bono, R; Pignata, C; Scursatone, E; Rovere, R; Natale, P; Gilli, G

1995-07-01

Considering its well-know toxicity and the chronic human exposure to lead, international law-makers enforced some directives or laws calling for the reduction of lead content of gasoline. All of these legislative acts aimed to reduce health risks for the general population. The aim of this study was to consider the effectiveness of these laws on air lead levels and consequently on blood lead levels in a randomly selected urban Italian population. In particular, these markers were analyzed over the course of several years, corresponding to the periods just before and after enforcements of the reductions of lead in petrol. Data presented point out some considerations: (1) enforcement of legislative measures concerning the reduction of lead in petrol has reduced atmospheric levels of lead. This result demonstrates a major environmental success in primary prevention efforts. (2) This success is clear especially considering that the actual Pb-B levels can be extended to the urbanized populations. Pb-B levels were consistently higher for drinkers, for older adults, and for males. The mean of Pb-B level for the present urbanized population is higher than the U.S. overall population (6.4 vs 3 microgram/dl). This difference can be also explained considering the different historical period of enforcement of the restriction laws.

Weathering steel as a potential source for metal contamination: Metal dissolution during 3-year of field exposure in a urban coastal site.

PubMed

Raffo, Simona; Vassura, Ivano; Chiavari, Cristina; Martini, Carla; Bignozzi, Maria C; Passarini, Fabrizio; Bernardi, Elena

2016-06-01

Surface and building runoff can significantly contribute to the total metal loading in urban runoff waters, with potential adverse effects on the receiving ecosystems. The present paper analyses the corrosion-induced metal dissolution (Fe, Mn, Cr, Ni, Cu) from weathering steel (Cor-Ten A) with or without artificial patinas, exposed for 3 years in unsheltered conditions at a marine urban site (Rimini, Italy). The influence of environmental parameters, atmospheric pollutants and surface finish on the release of dissolved metals in rain was evaluated, also by means of multivariate analysis (two-way and three-way Principal Component Analysis). In addition, surface and cross-section investigations were performed so as to monitor the patina evolution. The contribution provided by weathering steel runoff to the dissolved Fe, Mn and Ni loading at local level is not negligible and pre-patination treatments seem to worsen the performance of weathering steel in term of metal release. Metal dissolution is strongly affected by extreme events and shows seasonal variations, with different influence of seasonal parameters on the behaviour of bare or artificially patinated steel, suggesting that climate changes could significantly influence metal release from this alloy. Therefore, it is essential to perform a long-term monitoring of the performance, the durability and the environmental impact of weathering steel. Copyright © 2016 Elsevier Ltd. All rights reserved.

USING CMAQ FOR EXPOSURE MODELING AND CHARACTERIZING THE SUB-GRID VARIABILITY FOR EXPOSURE ESTIMATES

EPA Science Inventory

Atmospheric processes and the associated transport and dispersion of atmospheric pollutants are known to be highly variable in time and space. Current air quality models that characterize atmospheric chemistry effects, e.g. the Community Multi-scale Air Quality (CMAQ), provide vo...

Temporal characteristics of atmospheric CO2 in urban Nanjing, China

NASA Astrophysics Data System (ADS)

Huang, Xiaoxian; Wang, Tijian; Talbot, Robert; Xie, Min; Mao, Huiting; Li, Shu; Zhuang, Bingliang; Yang, Xiuqun; Fu, Congbin; Zhu, Jialei; Huang, Xing; Xu, Runying

2015-02-01

Although China is a big carbon dioxide (CO2) emitter, in situ measurements of atmospheric CO2 are sparse in urban China. The mixing ratio of carbon dioxide (CO2) and its influencing factors in urban Nanjing were investigated in this study, from the 18th of January to the 31st of December 2011. The annual average mixing ratio of CO2 was 406.5 ± 20.0 ppmv over the study period. The signal analysis using the fast Fourier transform (FFT) algorithm showed that CO2 had different cycles as a result of multiple controlling factors. The seasonal and intra-seasonal fluctuations of CO2 were mainly caused by the terrestrial biospheric uptake and emission and atmospheric oscillation. The weekly variation of CO2 was largely influenced by traffic volume. The diurnal cycle of CO2 presented a bimodal pattern in winter (DJF) probably due to the rush hour emissions. The seasonal mean CO2/CO correlation slope varied from 0.024 ppmv/ppbv to 0.029 ppmv/ppbv, comparable to the fossil fuel combustion emission ratio. The diurnal pattern of CO2/CO was irregular, indicating random anthropogenic emissions in an urban area. Firework setting was a large source of CO2 during the Spring Festival holiday. The backward trajectories by the HYSPLIT model showed that the local anthropogenic emissions contributed the most to the high CO2 mixing ratio in the urban area.

Moderate Imaging Resolution Spectroradiometer (MODIS) Aerosol Optical Depth Retrieval for Aerosol Radiative Forcing

NASA Astrophysics Data System (ADS)

Asmat, A.; Jalal, K. A.; Ahmad, N.

2018-02-01

The present study uses the Aerosol Optical Depth (AOD) retrieved from Moderate Imaging Resolution Spectroradiometer (MODIS) data for the period from January 2011 until December 2015 over an urban area in Kuching, Sarawak. The results show the minimum AOD value retrieved from MODIS is -0.06 and the maximum value is 6.0. High aerosol loading with high AOD value observed during dry seasons and low AOD monitored during wet seasons. Multi plane regression technique used to retrieve AOD from MODIS (AODMODIS) and different statistics parameter is proposed by using relative absolute error for accuracy assessment in spatial and temporal averaging approach. The AODMODIS then compared with AOD derived from Aerosol Robotic Network (AERONET) Sunphotometer (AODAERONET) and the results shows high correlation coefficient (R2) for AODMODIS and AODAERONET with 0.93. AODMODIS used as an input parameters into Santa Barbara Discrete Ordinate Radiative Transfer (SBDART) model to estimate urban radiative forcing at Kuching. The observed hourly averaged for urban radiative forcing is -0.12 Wm-2 for top of atmosphere (TOA), -2.13 Wm-2 at the surface and 2.00 Wm-2 in the atmosphere. There is a moderate relationship observed between urban radiative forcing calculated using SBDART and AERONET which are 0.75 at the surface, 0.65 at TOA and 0.56 in atmosphere. Overall, variation in AOD tends to cause large bias in the estimated urban radiative forcing.

Sub-kilometer Numerical Weather Prediction in complex urban areas

NASA Astrophysics Data System (ADS)

Leroyer, S.; Bélair, S.; Husain, S.; Vionnet, V.

2013-12-01

A Sub-kilometer atmospheric modeling system with grid-spacings of 2.5 km, 1 km and 250 m and including urban processes is currently being developed at the Meteorological Service of Canada (MSC) in order to provide more accurate weather forecasts at the city scale. Atmospheric lateral boundary conditions are provided with the 15-km Canadian Regional Deterministic Prediction System (RDPS). Surface physical processes are represented with the Town Energy Balance (TEB) model for the built-up covers and with the Interactions between the Surface, Biosphere, and Atmosphere (ISBA) land surface model for the natural covers. In this study, several research experiments over large metropolitan areas and using observational networks at the urban scale are presented, with a special emphasis on the representation of local atmospheric circulations and their impact on extreme weather forecasting. First, numerical simulations are performed over the Vancouver metropolitan area during a summertime Intense Observing Period (IOP of 14-15 August 2008) of the Environmental Prediction in Canadian Cities (EPiCC) observational network. The influence of the horizontal resolution on the fine-scale representation of the sea-breeze development over the city is highlighted (Leroyer et al., 2013). Then severe storms cases occurring in summertime within the Greater Toronto Area (GTA) are simulated. In view of supporting the 2015 PanAmerican and Para-Pan games to be hold in GTA, a dense observational network has been recently deployed over this region to support model evaluations at the urban and meso scales. In particular, simulations are conducted for the case of 8 July 2013 when exceptional rainfalls were recorded. Leroyer, S., S. Bélair, J. Mailhot, S.Z. Husain, 2013: Sub-kilometer Numerical Weather Prediction in an Urban Coastal Area: A case study over the Vancouver Metropolitan Area, submitted to Journal of Applied Meteorology and Climatology.

Changes in land use, climate and the environment during a period of rapid economic development in Jiangsu Province, China.

PubMed

Huang, Changchun; Zhang, Mingli; Zou, Jun; Zhu, A-Xing; Chen, Xia; Mi, Yin; Wang, Yanhua; Yang, Hao; Li, Yunmei

2015-12-01

Understanding changes in climate and environment on a regional scale can provide useful guidance for regional socio-economic development. The present study characterizes changes in the environment, climate, land use and cover types via in situ observed, statistical data and remote sensing images for Jiangsu Province, China, during the period 1980-2012. Statistical and spatial analyses indicate that the pace of urbanization in southern Jiangsu is more rapid than that in northern Jiangsu. Urbanization (92.7%) results primarily from the loss of farmland. While emissions of pollutants from industrial sources were well controlled, and wastewater, which more frequently derives from urban domestic sources, was found to be increasing. The rates of wastewater to population increased from 0.17±0.017 to 0.32±0.090 (billion ton/million persons) during the two periods of 1980-2000 and 2000-2012. However, the rates of wastewater to Gross Domestic Product (GDP) decreased from 0.26±0.20 to 0.014±0.009 (billion ton/billion Yuan), respectively. The significant increase in scattering radiance and Earth's albedo caused by the urbanization and its process (Pearson correlation coefficient (r) between urban land and scattering radiance=0.86, p<0.0001; r between farmland and scattering radiance=-0.92, p<0.0001) aggravates the warming in the regional scale. This correlation analysis indicates that temperature will decrease with the increase of woodland, grassland and farmland, and will increase with the increase of urbanized and unexploited lands. Added to warming caused by an increase in CO2, land use/cover change and human activities may be the primary reason for the rising temperatures in Jiangsu Province. The change in regional thermal conditions reduces both local humidity and land atmosphere flux exchange. The low atmosphere flux exhange contributes to the spread of atmospheric pollutants and the deposition of atmospheric particles. Copyright © 2015 Elsevier B.V. All rights reserved.

Hygiene, atopy and wheeze-eczema-rhinitis symptoms in schoolchildren from urban and rural Ecuador.

PubMed

Cooper, Philip J; Vaca, Maritza; Rodriguez, Alejandro; Chico, Martha E; Santos, Darci N; Rodrigues, Laura C; Barreto, Mauricio L

2014-03-01

Rural residence is protective against atopy and wheeze-rhinitis-eczema symptoms in developed countries, an effect attributed to farming and poor hygiene exposures. There are few data from developing countries addressing this question. We compared atopy and wheeze-rhinitis-eczema symptoms between urban and rural Ecuador, and explored the effects of farming and poor hygiene exposures. We performed cross sectional studies of schoolchildren living in rural and urban Ecuador. Data on symptoms and farming/hygiene exposures were collected by parental questionnaire, atopy by allergen skin prick test reactivity and geohelminth infections by stool examinations. Among 2526 urban and 4295 rural schoolchildren, prevalence was: atopy (10.0% vs 12.5%, p=0.06), wheeze (9.4% vs 10.1%, p=0.05), rhinitis (8.1% vs 6.4%, p=0.02) and eczema (5.9% vs 4.7%, p=0.06). A small proportion of symptoms were attributable to atopy (range 3.9-10.7%) with greater attributable fractions for respiratory symptoms observed in urban schoolchildren. Respiratory symptoms were associated with poor hygiene/farming exposures: wheeze with lack of access to potable water; and rhinitis with household pets, no bathroom facilities and contact with large farm animals. Birth order was inversely associated with respiratory symptoms. Area of residence and atopy had few effects on these associations. Urban schoolchildren living in Ecuador have a similar prevalence of atopy, eczema and wheeze but a higher prevalence of rhinitis compared with rural children. Some farming and poor hygiene exposures were associated with an increase in the prevalence of wheeze or rhinitis while birth order was inversely associated with these symptoms.

Hygiene, atopy and wheeze–eczema–rhinitis symptoms in schoolchildren from urban and rural Ecuador

PubMed Central

Cooper, Philip J; Vaca, Maritza; Rodriguez, Alejandro; Chico, Martha E; Santos, Darci N; Rodrigues, Laura C; Barreto, Mauricio L

2014-01-01

Background Rural residence is protective against atopy and wheeze–rhinitis–eczema symptoms in developed countries, an effect attributed to farming and poor hygiene exposures. There are few data from developing countries addressing this question. We compared atopy and wheeze–rhinitis–eczema symptoms between urban and rural Ecuador, and explored the effects of farming and poor hygiene exposures. Methods We performed cross sectional studies of schoolchildren living in rural and urban Ecuador. Data on symptoms and farming/hygiene exposures were collected by parental questionnaire, atopy by allergen skin prick test reactivity and geohelminth infections by stool examinations. Results Among 2526 urban and 4295 rural schoolchildren, prevalence was: atopy (10.0% vs 12.5%, p=0.06), wheeze (9.4% vs 10.1%, p=0.05), rhinitis (8.1% vs 6.4%, p=0.02) and eczema (5.9% vs 4.7%, p=0.06). A small proportion of symptoms were attributable to atopy (range 3.9–10.7%) with greater attributable fractions for respiratory symptoms observed in urban schoolchildren. Respiratory symptoms were associated with poor hygiene/farming exposures: wheeze with lack of access to potable water; and rhinitis with household pets, no bathroom facilities and contact with large farm animals. Birth order was inversely associated with respiratory symptoms. Area of residence and atopy had few effects on these associations. Conclusions Urban schoolchildren living in Ecuador have a similar prevalence of atopy, eczema and wheeze but a higher prevalence of rhinitis compared with rural children. Some farming and poor hygiene exposures were associated with an increase in the prevalence of wheeze or rhinitis while birth order was inversely associated with these symptoms. PMID:24105783

A casemix study of patients seen by a dermatology trainee in rural and urban outpatient settings.

PubMed

Tilakaratne, Dev; Warren, Lachlan; Menz, Jennifer

2016-02-01

For 8 years South Australian dermatologists have provided an outreach service to the Northern Territory (NT), including rural and remote areas. In 2012 and 2013, a trainee accompanied a dermatologist on these outreach visits. This is the first prospective study that documents the spectrum of dermatological diseases requiring outpatient specialist input in various settings in the NT, and also the first study to compare the clinical experience of one Australian dermatology trainee in urban and rural settings. Characteristics of patients managed primarily by the outreach dermatology registrar were recorded prospectively from February 2013 to July 2013. The data from the trainee's urban encounters were compared to that of the rural centres. The spectrum of conditions seen in these two settings was placed in the disease categories specified in the Australasian College of Dermatologists (ACD) curriculum. The Royal Adelaide Hospital outpatient experience provided greater exposure to skin neoplasms, lymphoproliferative and myeloproliferative disorders and non-infectious neutrophilic/eosinophilic disorders. The outreach sites provided greater exposure to infections, adnexal diseases and genodermatoses. Both urban and rural experiences provided a broad exposure to the disease categories outlined in the ACD curriculum. The spectrum of disease requiring specialist dermatology input varies between urban South Australia and rural NT. The inclusion of dermatology trainees in outreach visits broadens their clinical exposure. It is recommended that other dermatology service providers in Australia consider documenting clinical casemix comparisons to assess dermatology demand, outcomes and trainee exposure. © 2014 The Australasian College of Dermatologists.

Noise pollution and annoyance: an urban soundscapes study.

PubMed

de Paiva Vianna, Karina Mary; Alves Cardoso, Maria Regina; Rodrigues, Rui Manuel Calejo

2015-01-01

Since 1972, the World Health Organization (WHO) has declared noise as a pollutant. Over the last decades, the quality of the urban environment has attracted the interest of researchers due to the growing urban sprawl, especially in developing countries. The objective of this study was to evaluate the effects of noise exposure in six urban soundscapes: Areas with high and low levels of noise in scenarios of leisure, work, and home. Cross-sectional study. The study was conducted in two steps: Evaluation of noise levels, with the development of noise maps, and health related inquiries. 180 individuals were interviewed, being 60 in each scenario, divided into 30 exposed to high level of noise and 30 to low level. Chi-Square test and Ordered Logistic Regression Model (P < 0,005). 70% of the interviewees reported noticing some source of noise in the selected scenarios and it was observed an association between exposure and perception of some source of noise (P < 0.001). 41.7% of the interviewees reported some degree of annoyance, being that this was associated with exposure (P < 0.001). There was also an association between exposure in different scenarios and reports of poor quality of sleep (P < 0.001). In the scenarios of work and home, the chance of reporting annoyance increased when compared with the scenario of leisure. We conclude that the use of this sort of assessment may clarify the relationship between urban noise exposure and health.

Noise pollution and annoyance: An urban soundscapes study

PubMed Central

de Paiva Vianna, Karina Mary; Alves Cardoso, Maria Regina; Rodrigues, Rui Manuel Calejo

2015-01-01

Since 1972, the World Health Organization (WHO) has declared noise as a pollutant. Over the last decades, the quality of the urban environment has attracted the interest of researchers due to the growing urban sprawl, especially in developing countries. The objective of this study was to evaluate the effects of noise exposure in six urban soundscapes: Areas with high and low levels of noise in scenarios of leisure, work, and home. Cross-sectional study. The study was conducted in two steps: Evaluation of noise levels, with the development of noise maps, and health related inquiries. 180 individuals were interviewed, being 60 in each scenario, divided into 30 exposed to high level of noise and 30 to low level. Chi-Square test and Ordered Logistic Regression Model (P < 0,005). 70% of the interviewees reported noticing some source of noise in the selected scenarios and it was observed an association between exposure and perception of some source of noise (P < 0.001). 41.7% of the interviewees reported some degree of annoyance, being that this was associated with exposure (P < 0.001). There was also an association between exposure in different scenarios and reports of poor quality of sleep (P < 0.001). In the scenarios of work and home, the chance of reporting annoyance increased when compared with the scenario of leisure. We conclude that the use of this sort of assessment may clarify the relationship between urban noise exposure and health. PMID:25913551

Contribution of atmospheric dry deposition to stormwater loads for PAHs and trace metals in a small and highly trafficked urban road catchment.

PubMed

Al Ali, Saja; Debade, Xavier; Chebbo, Ghassan; Béchet, Béatrice; Bonhomme, Céline

2017-12-01

A deep understanding of pollutant buildup and wash-off is essential for accurate urban stormwater quality modeling and for the development of stormwater management practices, knowing the potential adverse impacts of runoff pollution on receiving waters. In the context of quantifying the contribution of airborne pollutants to the contamination of stormwater runoff and assessing the need of developing an integrated AIR-WATER modeling chain, loads of polycyclic aromatic hydrocarbons (PAHs) and metal trace elements (MTEs) are calculated in atmospheric dry deposits, stormwater runoff, and surface dust stock within a small yet highly trafficked urban road catchment (~ 30,000 vehicles per day) near Paris. Despite the important traffic load and according to the current definition of "atmospheric" source, atmospheric deposition did not account for more than 10% of the PAHs and trace metal loads in stormwater samples for the majority of the events, based on the ratio of deposition to stormwater. This result shows that atmospheric deposition is not a major source of pollutants in stormwater, and thus, linking the air and water compartment in a modeling chain to have more accurate estimates of pollutant loads in stormwater runoff might not be relevant. Comparison of road dust with water samples demonstrates that only the fine fraction of the available stock is eroded during a rainfall event. Even if the atmosphere mostly generates fine particles, the existence of other sources of fine particles to stormwater runoff is highlighted.

Longitudinal and contemporaneous manganese exposure in apartheid-era South Africa: Implications for the past and future.

PubMed

Hess, Catherine A; Smith, Martin J; Trueman, Clive; Schutkowski, Holger

2015-03-01

Manganese is a potent environmental toxin, with significant effects on human health. Manganese exposure is of particular concern in South Africa where in the last decade, lead in gasoline has been replaced by methylcyclopentadienyl manganese tricarbonyl (MMT). We investigated recent historical levels of manganese exposure in urban Gauteng, South Africa prior to the introduction of MMT in order to generate heretofore non-existent longitudinal public health data on manganese exposure in urban South Africans. Cortical bone manganese concentration was measured by inductively coupled plasma mass spectrometer in 211 deceased adults with skeletal material from a fully identified archived tissue collection at the University of Pretoria, South Africa. All tissues came from individuals who lived and died in urban Gauteng (Transvaal), between 1958 and 1998. Median Mn concentration within the sampled tissues was 0.3μgg -1 , which is within reported range for bone manganese concentration in non-occupationally exposed populations and significantly below that reported in individuals environmentally exposed to MMT. No significant differences were seen in bone Mn between men and women or in individuals of different ethnicity, which further suggests environmental, as opposed to occupational exposure. There were no significant temporal or geographic differences in bone Mn. The results suggest that Mn exposure was low and uniformly distributed across the whole population prior to the introduction of MMT as a gasoline additive. In addition, should manganese exposure follow the same patterns as vehicle-emitted lead, a clear pattern of exposure will emerge with individuals in the urban core facing the greatest manganese exposure. Copyright © 2014 Elsevier Inc. All rights reserved.

Prenatal Exposure to Urban Air Nanoparticles in Mice Causes Altered Neuronal Differentiation and Depression-Like Responses

PubMed Central

Godar, Sean C.; Sander, Thomas K.; Iwata, Nahoko; Pakbin, Payam; Shih, Jean C.; Berhane, Kiros; McConnell, Rob; Sioutas, Constantinos

2013-01-01

Emerging evidence suggests that excessive exposure to traffic-derived air pollution during pregnancy may increase the vulnerability to neurodevelopmental alterations that underlie a broad array of neuropsychiatric disorders. We present a mouse model for prenatal exposure to urban freeway nanoparticulate matter (nPM). In prior studies, we developed a model for adult rodent exposure to re-aerosolized urban nPM which caused inflammatory brain responses with altered neuronal glutamatergic functions. nPMs are collected continuously for one month from a local freeway and stored as an aqueous suspension, prior to re-aerosolization for exposure of mice under controlled dose and duration. This paradigm was used for a pilot study of prenatal nPM impact on neonatal neurons and adult behaviors. Adult C57BL/6J female mice were exposed to re-aerosolized nPM (350 µg/m3) or control filtered ambient air for 10 weeks (3×5 hour exposures per week), encompassing gestation and oocyte maturation prior to mating. Prenatal nPM did not alter litter size, pup weight, or postnatal growth. Neonatal cerebral cortex neurons at 24 hours in vitro showed impaired differentiation, with 50% reduction of stage 3 neurons with long neurites and correspondingly more undifferentiated neurons at Stages 0 and 1. Neuron number after 24 hours of culture was not altered by prenatal nPM exposure. Addition of exogenous nPM (2 µg/ml) to the cultures impaired pyramidal neuron Stage 3 differentiation by 60%. Adult males showed increased depression-like responses in the tail-suspension test, but not anxiety-related behaviors. These pilot data suggest that prenatal exposure to nPM can alter neuronal differentiation with gender-specific behavioral sequelae that may be relevant to human prenatal exposure to urban vehicular aerosols. PMID:23734187

Multi-year air monitoring of legacy and current-use brominated flame retardants in an urban center in northeastern China.

PubMed

Li, Wen-Long; Huo, Chun-Yan; Liu, Li-Yan; Song, Wei-Wei; Zhang, Zi-Feng; Ma, Wan-Li; Qiao, Li-Na; Li, Yi-Fan

2016-11-15

The occurrence and temporal trends of polybrominated diphenyl ethers (PBDEs) and non-PBDE brominated flame retardants (NBFRs) were investigated in an urban atmosphere of Northeast China in consecutive six years (2008-2013). Among all chemicals, BDE-209, l,2,5,6,9,10-hexabromocyclododecane (HBCD), and decabromodiphenylethane (DBDPE) were the three most dominant compounds. During the period, the levels of pentabromodiphenyl ethers in the gas-phase and octabromodiphenyl ethers in the particle-phase significantly decreased, while the levels of BDE-209 and NBFRs increased in either the gas-phase or particle-phase. Ambient temperature was the most significant variable that influenced the gas-phase and particle-phase concentrations of BFRs, followed by wind speed and relative humidity. A stronger temperature dependence of the atmospheric concentrations was found for lower mass BFRs. Gas-particle partitioning studies suggested PBDEs in the urban atmosphere of Northeast China were at steady-state. Steady-state equation can also well describe the partitioning behavior for NBFRs, suggesting that the atmospheric partitioning behaviors of NBFRs were similar to those of PBDEs. Copyright © 2016 Elsevier B.V. All rights reserved.

Exposure to hazardous volatile organic compounds, PM 10 and CO while walking along streets in urban Guangzhou, China

NASA Astrophysics Data System (ADS)

Zhao, Lirong; Wang, Xinming; He, Qiusheng; Wang, Hao; Sheng, Guoying; Chan, L. Y.; Fu, Jiamo; Blake, D. R.

Toxic air pollutants in street canyons are important issues concerning public health especially in some large Asian cities like Guangzhou. In 1998 <18% of Guangzhou citizens used public transportation modes, with a majority commuting on foot (42%) or by bicycle (22%). Of the pedestrians, 57% were either senior citizens or students. In the present study, we measured toxic air pollutants while walking along urban streets in Guangzhou to evaluate pedestrian exposure. Volatile organic compounds (VOCs) were collected with sorbent tubes, and PM 10 and CO were measured simultaneously with portable analyzers. Our results showed that pedestrian exposure to PM 10 (with an average of 303 μg m -3 for all samples) and some toxic VOCs (for example, benzene) was relatively high. Monocyclic aromatic hydrocarbons were found to be the most abundant VOCs, and 71% of the samples had benzene levels higher than 30 μg m -3. Benzene, PM 10 and CO in walk-only streets were significantly lower ( p<0.05) than in traffic streets, and the differences in exposure levels between new urban streets and old urban streets were highly significant ( p<0.01). Pedestrian exposure to toxic VOCs and PM 10 was higher than those reported in other public transportation modes (bus and subway). The good correlations between BTEX, PM 10 and CO in the streets indicated that automotive emission might be their major source. Our study also showed that the risk to pedestrians due to air pollution was misinterpreted by the reported air quality index based on measurement of SO 2, NO x and PM 10 in the government monitoring stations. An urban roadside monitoring station might be needed by air quality monitoring networks in large Asian cities like Guangzhou, in order to survey exposure to air toxics in urban roadside microenvironments.

Model developments in TERRA_URB, the upcoming standard urban parametrization of the atmospheric numerical model COSMO(-CLM)

NASA Astrophysics Data System (ADS)

Wouters, Hendrik; Blahak, Ulrich; Helmert, Jürgen; Raschendorfer, Matthias; Demuzere, Matthias; Fay, Barbara; Trusilova, Kristina; Mironov, Dmitrii; Reinert, Daniel; Lüthi, Daniel; Machulskaya, Ekaterina

2015-04-01

In order to address urban climate at the regional scales, a new efficient urban land-surface parametrization TERRA_URB has been developed and coupled to the atmospheric numerical model COSMO-CLM. Hereby, several new advancements for urban land-surface models are introduced which are crucial for capturing the urban surface-energy balance and its seasonal dependency in the mid-latitudes. This includes a new PDF-based water-storage parametrization for impervious land, the representation of radiative absorption and emission by greenhouse gases in the infra-red spectrum in the urban canopy layer, and the inclusion of heat emission from human activity. TERRA_URB has been applied in offline urban-climate studies during European observation campaigns at Basel (BUBBLE), Toulouse (CAPITOUL), and Singapore, and currently applied in online studies for urban areas in Belgium, Germany, Switzerland, Helsinki, Singapore, and Melbourne. Because of its computational efficiency, high accuracy and its to-the-point conceptual easiness, TERRA_URB has been selected to become the standard urban parametrization of the atmospheric numerical model COSMO(-CLM). This allows for better weather forecasts for temperature and precipitation in cities with COSMO, and an improved assessment of urban outdoor hazards in the context of global climate change and urban expansion with COSMO-CLM. We propose additional extensions to TERRA_URB towards a more robust representation of cities over the world including their structural design. In a first step, COSMO's standard EXTernal PARarameter (EXTPAR) tool is updated for representing the cities into the land cover over the entire globe. Hereby, global datasets in the standard EXTPAR tool are used to retrieve the 'Paved' or 'sealed' surface Fraction (PF) referring to the presence of buildings and streets. Furthermore, new global data sets are incorporated in EXTPAR for describing the Anthropogenic Heat Flux (AHF) due to human activity, and optionally the Surface Area Index (SAI) derived from the Floor Space Index (FSI). In a second step, it is focussed on the urban/rural contrast in terms of turbulent transport in the surface layer by means of model sensivity experiments: On the theoretical basis of the TKE-based surface-layer transfer scheme of COSMO, we investigate the consistency between empirical functions for thermal roughness lengths and the urban/rural canopy morphology.

Exposure to air pollution is associated with lung hyperinflation in healthy children and adolescents in Southwest Mexico City: a pilot study.

PubMed

Calderón-Garcidueñas, L; Mora-Tiscareño, A; Chung, C J; Valencia, G; Fordham, L A; García, R; Osnaya, N; Romero, L; Acuña, H; Villarreal-Calderón, A; Devlin, R B; Koren, H S

2000-06-01

Air pollution produces adverse health effects. The consequences of lifelong daily exposures to atmospheric pollutants upon the respiratory apparatus of healthy children are of considerable clinical importance. We investigated the association between exposure to a highly polluted urban environment with a complex mixture of air pollutants-ozone and particulate matter the predominant ones-and chest x-ray abnormalities in 59 healthy Mexican children who are lifelong residents of Southwest Metropolitan Mexico City (SWMMC), with a negative history of tobacco exposure and respiratory illnesses. Their clinical results and x-ray findings were compared to those of 19 Mexican control children, residents of a low-pollution area, with a similar negative history of tobacco exposure and respiratory illnesses. Ozone concentrations in SWMMC exceeded the U.S. Environmental Protection Agency (U.S. EPA) National Ambient Air Quality Standard (NAAQS) for O(3): 0.08 ppm as 1-h maximal concentration, not to be exceeded more than 4 times a year, on 71% of days in 1986 and 95% in 1997, with values as high as 0.48 ppm. Ozone maximal peaks are usually recorded between 2 and 5 pm coinciding with children's outdoor physical activities. Children in the control group reported no upper or lower respiratory symptomatology. Every SWMMC child complained of upper and/or lower respiratory symptoms, including epistaxis, nasal dryness and crusting, cough, shortness of breath, and chest discomfort. Children aged 7-13 yr had the most symptomatology, while 5- to 6-year olds and adolescents with the lowest number of statistically significant outdoor exposure hours had less respiratory symptoms. Bilateral symmetric mild lung hyperinflation was significantly associated with exposure to the SWMMC atmosphere (p = .0004). Chronic and sustained inhalation of a complex mixture of air pollutants, including ozone and particulate matter (PM), is associated with lung hyperinflation, suggestive of small airway disease, in a population of clinically healthy children and adolescents. Small airways are a target of air pollutants in SWMMC children, with ozone and PM being most likely responsible, based on experimental animal, controlled-chamber, and epidemiological data available. Our main concern is the potential likelihood for the development of chronic lung disease in this highly exposed population.

Soil nitrogen levels are linked to decomposition enzyme activities along an urban-remote tropical forest gradient

Treesearch

D. F. Cusack

2013-01-01

Urban areas in tropical regions are expanding rapidly, with significant potential to affect local ecosystem dynamics. In particular, nitrogen (N) availability may increase in urban-proximate forests because of atmospheric N deposition. Unlike temperate forests, many tropical forests on highly weathered soils have high background N availability, so plant growth is...

Restoring ecosystem resilience to urban forests using Dutch elm disease-tolerant American elm trees

Treesearch

Charles E. Flower; Cornelia C. Pinchot; James M. Slavicek

2017-01-01

Urban forests contribute significantly to human health and environmental quality (Sanesi et al. 2011). As such, maintaining healthy urban forests resilient to pollution (atmospheric and soil), high temperatures, compacted soils, and poor drainage is critical. However, these forests have been hard hit by development, pests, and pathogens, consequently reshaping their...

COST 728 Project Report: Urbanization of Meteorological and Air Quality Models - Chapter 5 - Model Urbanization Strategy: Summaries, Recommendations and Requirements

EPA Science Inventory

The urban canopy (UC), the layer of the atmosphere between the ground and the top of the highest buildings, is the region where people live and human activities take place. Because of this importance (e.g., human health, preservation of buildings) significant efforts have been d...

Morbidity Forecast in Cities: A Study of Urban Air Pollution and Respiratory Diseases in the Metropolitan Region of Curitiba, Brazil.

PubMed

de Souza, Fabio Teodoro

2018-05-29

In the last two decades, urbanization has intensified, and in Brazil, about 90% of the population now lives in urban centers. Atmospheric patterns have changed owing to the high growth rate of cities, with negative consequences for public health. This research aims to elucidate the spatial patterns of air pollution and respiratory diseases. A data-based model to aid local urban management to improve public health policies concerning air pollution is described. An example of data preparation and multivariate analysis with inventories from different cities in the Metropolitan Region of Curitiba was studied. A predictive model with outstanding accuracy in prediction of outbreaks was developed. Preliminary results describe relevant relations among morbidity scales, air pollution levels, and atmospheric seasonal patterns. The knowledge gathered here contributes to the debate on social issues and public policies. Moreover, the results of this smaller scale study can be extended to megacities.

Secondhand smoke exposure is associated with smoke-free laws but not urban/rural status.

PubMed

Lee, Kiyoung; Hwang, Yunhyung; Hahn, Ellen J; Bratset, Hilarie; Robertson, Heather; Rayens, Mary Kay

2015-05-01

The objective was to determine secondhand smoke (SHS) exposure with and without smoke-free laws in urban and rural communities. The research hypothesis was that SHS exposure in public places could be improved by smoke-free law regardless of urban and rural status. Indoor air quality in hospitality venues was assessed in 53 communities (16 urban and 37 rural) before smoke-free laws; 12 communities passed smoke-free laws during the study period. Real-time measurements of particulate matter with 2.5 µm aerodynamic diameter or smaller (PM2.5) were taken 657 times from 586 distinct venues; about 71 venues had both pre- and post-law measurements. Predictors of log-transformed PM2.5 level were determined using multilevel modeling. With covariates of county-level percent minority population, percent with at least high school education, adult smoking rate, and venue-level smoker density, indoor air quality was associated with smoke-free policy status and venue type and their interaction. The geometric means for restaurants, bars, and other public places in communities without smoke-free policies were 22, 63, and 25 times higher than in those with smoke-free laws, respectively. Indoor air quality was not associated with urban status of venue, and none of the interactions involving urban status were significant. SHS exposure in public places did not differ by urban/rural status. Indoor air quality was associated with smoke-free law status and venue type. This study analyzed 657 measurements of indoor PM2.5 level in 53 communities in Kentucky, USA. Although indoor air quality in public places was associated with smoke-free policy status and venue type, it did not differ by urban and rural status. The finding supports the idea that population in rural communities can be protected with smoke-free policy. Therefore, it is critical to implement smoke-free policy in rural communities as well as urban areas.

Human-Induced Climate Variations Linked to Urbanization: From Observations to Modeling

NASA Technical Reports Server (NTRS)

Shepherd, J. Marshall; Jin, Menglin

2004-01-01

The goal of this session is to bring together scientists from interdisciplinary backgrounds to discuss the data, scientific approaches and recent results focusing on the impact of urbanization on the climate. The discussion will highlight current observational and modeling capabilities being employed for investigating the urban environment and its linkage to the change in the Earth's climate system. The goal of the session is to identify our current stand and the future direction on the topic. Urbanization is one of the extreme cases of land use change. Most of population of the world has moved to urban areas. By 1995, more than 70% of population of North America and Europe were living in cities. By 2025, the United Nations estimates that 60% of the worlds population will live in cities. Although currently only 1.2% of the land is urban, better understanding of how the atmosphere-ocean-land-biosphere components interact as a coupled system and the influence of human activities on this system is critical. Our understanding of urbanization effect is incomplete, partly because human activities induce new changes on climate in addition to the original natural variations, and partly because previously few data available for study urban effect globally. Urban construction changes surface roughness, albedo, heat capacity and vegetation coverage. Traffic and industry increase atmospheric aerosol. It is suggested that urbanization may modify rainfall processes through aerosol-cloud interactions or dynamic feedbacks. Because urbanization effect on climate is determined by many factors including land cover, the city's microscale features, population density, and human lifestyle patterns, it is necessary to study urban areas over globe.

Indoor dust and air concentrations of endotoxin in urban and rural environments.

PubMed

Barnig, C; Reboux, G; Roussel, S; Casset, A; Sohy, C; Dalphin, J-C; de Blay, F

2013-03-01

Rural dairy farming is associated with high exposure to indoor endotoxins as compared to rural nonfarming houses and urban houses. The time spent on the mattress (7 h for an adult) and of the proximity of the contaminated source should be taken into account with the other causes of exposure. Studies in European children from a farming background have shown that these children have a reduced risk of asthma and atopic sensitization compared to their urban counterparts. It has been suggested that this might be due to exposure to high levels of endotoxin in the farming environment. The aim of this study was to compare indoor endotoxin concentrations in air and dust samples from randomly selected urban and rural dwellings. In the rural area, endotoxins were analysed in farmhouses and nonfarmhouses as well as housing characteristics, lifestyle factors and agricultural practices likely to influence air and dust endotoxin levels. Endotoxin levels were significantly higher in floor (6600 ± 6100 vs 3600 ± 5600 and 3800 ± 17,000 ng g⁻¹; P < 0·001) and mattress dust (2900 ± 4100 vs 1100 ± 2400 and 800 ± 2600 ng g⁻¹; P < 0·001) from farmhouses compared to other rural and urban homes. However, no difference was observed between endotoxin concentrations in the air of urban and rural houses, and airborne endotoxin levels did not correlate to dust levels. Lack of ventilation and direct entry into the house were correlated with an increase in dust endotoxin levels. These results confirm that dairy farming is associated with high exposure to endotoxins in indoor dust samples. No difference was observed between indoor airborne concentrations between urban and rural houses. These results suggest that measuring endotoxin in dust is the most relevant method to assess endotoxin exposure. © 2012 The Society for Applied Microbiology.

Comparative Toxicity of Simulated Smog Atmospheres in ...

EPA Pesticide Factsheets

Effects of complex regional multipollutant mixtures on disease expression in susceptible populations are dependent on multiple exposure and susceptibility factors. Differing profiles of ozone (O3), nitrogen dioxide (NO2), and particulate matter (PM), which are key components of smog, and other hazardous pollutants may develop as a result of regional-specific geographic and urban environment characteristics. We investigated the pulmonary effects of two smog mixtures with different compositions in a mouse model of allergic airway disease to determine which source profile had the greatest impact on pulmonary endpoints. A hydrocarbon mixture was combined with NO gas in the presence of UV light in a controlled setting. Simulated smog atmosphere 1 (SSA-1) consisted of concentrations of 1070 µg/m3 secondary organic aerosol (SOA), 0.104 ppm O3, and 0.252 ppm NO2. SSA-2 consisted of a starting concentration of 53 µg/m3 SOA, 0.376 ppm O3, and 0.617 ppm NO2. An increased aerosol concentration was noted in the exposure chamber. Healthy and house dust mite (HDM)-sensitized (allergic) female BALB/cJ mice were exposed 4 hr/day for 1 or 5 days to either smog mixture or clean air. Two days after HDM challenge, airway mechanics were tested in anesthetized ventilated mice. Following methacholine aerosol challenge, increased airway resistance and elastance and a decrease in lung compliance were consistently observed in air- and smog-exposed HDM-allergic groups compared with non-a

Considerations for the design and technical setup of a human whole-body exposure chamber.

PubMed

Monsé, Christian; Sucker, Kirsten; van Thriel, Christoph; Broding, Horst Christoph; Jettkant, Birger; Berresheim, Hans; Wiethege, Thorsten; Käfferlein, Heiko; Merget, Rolf; Bünger, Jürgen; Brüning, Thomas

2012-01-01

Exposures to air contaminants, such as chemical vapors and particulate matter, pose important health hazards at workplaces. Short-term experimental exposures to chemical vapors and particles in humans are a promising attempt to investigate acute effects of such hazards. However, a significant challenge in this field is the determination of effects of co-exposures to more than one chemical or mixtures of chemical vapors and/or particles. To overcome such a challenge, studies have to be conducted under standardized exposure characterization and real time measurements, if possible. A new exposure laboratory (ExpoLab) was installed at IPA, combining sophisticated engineering designs with new analytical techniques, to fulfill these requirements. Low-dose as well as high-dose exposure scenarios are achieved by means of a calibration-gas-generator. Exposure monitoring can be carried out with a high performance real time mass spectrometer and other suitable analyzers (e.g. gas chromatograph). Numerous automated security facilities guarantee the physical integrity of the volunteers, and the waste atmosphere is removed using either charcoal filtration or catalytic post-combustion. Measurements of sulfur hexafluoride, carbon dioxide, aniline and carbon black are presented to demonstrate the performance of the exposure unit with respect to the temporal and spatial stability of generated atmospheres. The variations of generated contents in the atmospheres at steady state are slightly higher than the measurement precision of the analyzers (the typical standard deviation of generated atmospheres is < 2%). The technical components of ExpoLab and its monitoring systems ensure high quality standards in validity and reliability of generating and measuring exposure atmospheres.

Assessing the atmospheric oxidation of pesticides used to control mosquito populations in Houston, TX.

NASA Astrophysics Data System (ADS)

Usenko, S.; Clark, A. E.; Yoon, S.; Sheesley, R. J.

2016-12-01

In September 2013, NASA initiated the DISCOVER-AQ (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality) Houston campaign, which collected satellite and ground-based data to better understand air quality in the Houston metropolitan area. In conjunction with DISCOVER-AQ, particulate matter samples including total suspended particle (TSP) and particulate matter less than 2.5 microns in aerodynamic diameter (PM2.5) were collected at four ground-based sites across Houston. Aliquots of PM samples were analyzed for pesticide used to control mosquito populations in urban areas. Pesticides extracted using pressurized liquid extraction and extracts were analyzed using gas chromatography mass spectrometry. These pesticides, also known as adulticides, are aerosolized and sprayed in neighborhoods throughout Houston around sunset in an effort to reduce or prevent the spread of diseases like West Nile Virus and Zika. When these pesticides enter the atmosphere they oxidize after reaction with ozone and nitrate radical and become more toxic and less volatile. The rate and specific mechanism associated with this urban chemistry is currently unknown, but has direct implications on public health from both a toxicological and disease control standpoint. Preliminary atmospheric measurements in Houston demonstrated significant nighttime oxidation of malathion to malaoxon. Atmospheric half-lives measured near downtown Houston where 10x lower than previous agriculture based studies ( 5 days to less than 24 hours). Atmospheric nighttime PM concentrations of adulticides exceeded 60 ng/m3, which is orders of magnitude greater than concentrations of organic tracers associated with incomplete combustion. This unique system also offers an opportunity to address some key scientific questions including focusing on SVOC urban fate and urban transport as well as nighttime oxidation.

Assessing residential exposure to urban noise using environmental models: does the size of the local living neighborhood matter?

PubMed

Tenailleau, Quentin M; Bernard, Nadine; Pujol, Sophie; Houot, Hélène; Joly, Daniel; Mauny, Frédéric

2015-01-01

Environmental epidemiological studies rely on the quantification of the exposure level in a surface defined as the subject's exposure area. For residential exposure, this area is often the subject's neighborhood. However, the variability of the size and nature of the neighborhoods makes comparison of the findings across studies difficult. This article examines the impact of the neighborhood's definition on environmental noise exposure levels obtained from four commonly used sampling techniques: address point, façade, buffers, and official zoning. A high-definition noise model, built on a middle-sized French city, has been used to estimate LAeq,24 h exposure in the vicinity of 10,825 residential buildings. Twelve noise exposure indicators have been used to assess inhabitants' exposure. Influence of urban environmental factors was analyzed using multilevel modeling. When the sampled area increases, the average exposure increases (+3.9 dB), whereas the SD decreases (-1.6 dB) (P<0.01). Most of the indicators differ statistically. When comparing indicators from the 50-m and 400-m radius buffers, the assigned LAeq,24 h level varies across buildings from -9.4 to +22.3 dB. This variation is influenced by urban environmental characteristics (P<0.01). On the basis of this study's findings, sampling technique, neighborhood size, and environmental composition should be carefully considered in further exposure studies.

Frontiers in Atmospheric Chemistry Modelling

NASA Astrophysics Data System (ADS)

Colette, Augustin; Bessagnet, Bertrand; Meleux, Frederik; Rouïl, Laurence

2013-04-01

The first pan-European kilometre-scale atmospheric chemistry simulation is introduced. The continental-scale air pollution episode of January 2009 is modelled with the CHIMERE offline chemistry-transport model with a massive grid of 2 million horizontal points, performed on 2000 CPU of a high performance computing system hosted by the Research and Technology Computing Center at the French Alternative Energies and Atomic Energy Commission (CCRT/CEA). Besides the technical challenge, which demonstrated the robustness of the selected air quality model, we discuss the added value in terms of air pollution modelling and decision support. The comparison with in-situ observations shows that model biases are significantly improved despite some spurious added spatial variability attributed to shortcomings in the emission downscaling process and coarse resolution of the meteorological fields. The increased spatial resolution is clearly beneficial for the detection of exceedances and exposure modelling. We reveal small scale air pollution patterns that highlight the contribution of city plumes to background air pollution levels. Up to a factor 5 underestimation of the fraction of population exposed to detrimental levels of pollution can be obtained with a coarse simulation if subgrid scale correction such as urban increments are ignored. This experiment opens new perspectives for environmental decision making. After two decades of efforts to reduce air pollutant emissions across Europe, the challenge is now to find the optimal trade-off between national and local air quality management strategies. While the first approach is based on sectoral strategies and energy policies, the later builds upon new alternatives such as urban development. The strategies, the decision pathways and the involvement of individual citizen differ, and a compromise based on cost and efficiency must be found. We illustrated how high performance computing in atmospheric science can contribute to this aim. Although further developments are still needed to secure the results for routine policy use, the door is now open...

Health risk assessment of heavy metals in atmospheric deposition in a congested city environment in a developing country: Kandy City, Sri Lanka.

PubMed

Weerasundara, Lakshika; Magana-Arachchi, D N; Ziyath, Abdul M; Goonetilleke, Ashantha; Vithanage, Meththika

2018-08-15

This research study which was undertaken in a congested city environment in a developing country provides a robust approach for the assessment and management of human health risk associated with atmospheric heavy metals. The case study area was Kandy City, which is the second largest city in Sri Lanka and bears the characteristics of a typical city in the developing world such as the urban footprint, high population density and traffic congestion. Atmospheric deposition samples were collected on a weekly basis and analyzed for nine heavy metals common to urban environments, namely, Al, Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb. Health risk was assessed using hazard quotient (HQ) and hazard index (HI), while the cancer risk was evaluated based on life time daily cancer risk. Al and Fe were found to be in relatively high concentrations due to the influence of both, natural and anthropogenic sources. High Zn loads were attributed to vehicular emissions and the wide use of Zn coated building materials. Contamination factor and geo-accumulation index showed that currently, Al and Fe are at uncontaminated levels and other metals are in the range of uncontaminated to contaminated levels, but with the potential to exacerbate in the long-term. The health risk assessment showed that the influence of the three exposure pathways were in the order of ingestion > dermal contact > inhalation. The HQ and HI values for children for the nine heavy metals were higher than that for adults, indicating that children may be subjected to potentially higher health risk than adults. The study methodology and outcomes provide fundamental knowledge to regulatory authorities to determine appropriate mitigation measures in relation to HM pollution in city environments in the developing world, where to-date only very limited research has been undertaken. Copyright © 2018 Elsevier Ltd. All rights reserved.

Heavy Metal Pollution in Settled Dust Associated with Different Urban Functional Areas in a Heavily Air-Polluted City in North China.

PubMed

Wan, Dejun; Han, Zhangxiong; Yang, Jinsong; Yang, Guanglin; Liu, Xingqi

2016-11-10

Understanding variations of heavy metals in atmospheric particles between different functional areas is significant for pollution control and urban planning in cities. To reveal pollution and spatial distribution of heavy metals in atmospheric particles from different urban functional areas in Shijiazhuang in North China, 43 settled dust samples were collected over the main urban area and heavy metal concentrations were determined in their <63 μm fractions using an ICP-OES. The results suggest that Cr, Mn, Fe, Co, Ni, and V in the dust are not or slightly enriched and their concentrations vary slightly between different sites, implying their natural origins; whereas Cu, Zn, Cd, and Pb are often notably enriched and their concentrations vary significantly between different functional areas, indicating their anthropogenic sources. Integrated pollution indexes (IPIs) of the ten heavy metals are 2.7-13.6 (5.7 ± 2.2), suggesting high or very high pollution levels of most dust. Relatively lower IPIs occur mainly in the administration-education area, the commercial area, and other unclassified sites; while peaks occur mainly in the North Railway Station, the northeastern industrial area, and some sites near heavily trafficked areas, implying the significant influence of intensive industrial (including coal combustion) and traffic activities on atmospheric heavy metal accumulation. These results suggest a clear need of mitigating atmospheric heavy metal pollution via controlling emissions of toxic metals (especially Cd and Pb) from industrial and traffic sources in the city.

Heavy Metal Pollution in Settled Dust Associated with Different Urban Functional Areas in a Heavily Air-Polluted City in North China

PubMed Central

Wan, Dejun; Han, Zhangxiong; Yang, Jinsong; Yang, Guanglin; Liu, Xingqi

2016-01-01

Understanding variations of heavy metals in atmospheric particles between different functional areas is significant for pollution control and urban planning in cities. To reveal pollution and spatial distribution of heavy metals in atmospheric particles from different urban functional areas in Shijiazhuang in North China, 43 settled dust samples were collected over the main urban area and heavy metal concentrations were determined in their <63 μm fractions using an ICP-OES. The results suggest that Cr, Mn, Fe, Co, Ni, and V in the dust are not or slightly enriched and their concentrations vary slightly between different sites, implying their natural origins; whereas Cu, Zn, Cd, and Pb are often notably enriched and their concentrations vary significantly between different functional areas, indicating their anthropogenic sources. Integrated pollution indexes (IPIs) of the ten heavy metals are 2.7–13.6 (5.7 ± 2.2), suggesting high or very high pollution levels of most dust. Relatively lower IPIs occur mainly in the administration-education area, the commercial area, and other unclassified sites; while peaks occur mainly in the North Railway Station, the northeastern industrial area, and some sites near heavily trafficked areas, implying the significant influence of intensive industrial (including coal combustion) and traffic activities on atmospheric heavy metal accumulation. These results suggest a clear need of mitigating atmospheric heavy metal pollution via controlling emissions of toxic metals (especially Cd and Pb) from industrial and traffic sources in the city. PMID:27834903

Comparison of the impacts of urban development and climate change on exposing European cities to pluvial flooding

NASA Astrophysics Data System (ADS)

Skougaard Kaspersen, Per; Høegh Ravn, Nanna; Arnbjerg-Nielsen, Karsten; Madsen, Henrik; Drews, Martin

2017-08-01

The economic and human consequences of extreme precipitation and the related flooding of urban areas have increased rapidly over the past decades. Some of the key factors that affect the risks to urban areas include climate change, the densification of assets within cities and the general expansion of urban areas. In this paper, we examine and compare quantitatively the impact of climate change and recent urban development patterns on the exposure of four European cities to pluvial flooding. In particular, we investigate the degree to which pluvial floods of varying severity and in different geographical locations are influenced to the same extent by changes in urban land cover and climate change. We have selected the European cities of Odense, Vienna, Strasbourg and Nice for analyses to represent different climatic conditions, trends in urban development and topographical characteristics. We develop and apply a combined remote-sensing and flood-modelling approach to simulate the extent of pluvial flooding for a range of extreme precipitation events for historical (1984) and present-day (2014) urban land cover and for two climate-change scenarios (i.e. representative concentration pathways, RCP 4.5 and RCP 8.5). Changes in urban land cover are estimated using Landsat satellite imagery for the period 1984-2014. We combine the remote-sensing analyses with regionally downscaled estimates of precipitation extremes of current and expected future climate to enable 2-D overland flow simulations and flood-hazard assessments. The individual and combined impacts of urban development and climate change are quantified by examining the variations in flooding between the different simulations along with the corresponding uncertainties. In addition, two different assumptions are examined with regards to the development of the capacity of the urban drainage system in response to urban development and climate change. In the stationary approach, the capacity resembles present-day design, while it is updated in the evolutionary approach to correspond to changes in imperviousness and precipitation intensities due to urban development and climate change respectively. For all four cities, we find an increase in flood exposure corresponding to an observed absolute growth in impervious surfaces of 7-12 % during the past 30 years of urban development. Similarly, we find that climate change increases exposure to pluvial flooding under both the RCP 4.5 and RCP 8.5 scenarios. The relative importance of urban development and climate change on flood exposure varies considerably between the cities. For Odense, the impact of urban development is comparable to that of climate change under an RCP 8.5 scenario (2081-2100), while for Vienna and Strasbourg it is comparable to the impacts of an RCP 4.5 scenario. For Nice, climate change dominates urban development as the primary driver of changes in exposure to flooding. The variation between geographical locations is caused by differences in soil infiltration properties, historical trends in urban development and the projected regional impacts of climate change on extreme precipitation. Developing the capacity of the urban drainage system in relation to urban development is found to be an effective adaptation measure as it fully compensates for the increase in run-off caused by additional sealed surfaces. On the other hand, updating the drainage system according to changes in precipitation intensities caused by climate change only marginally reduces flooding for the most extreme events.

Monitoring of trace element atmospheric deposition using dry and wet moss bags: accumulation capacity versus exposure time.

PubMed

Anicić, M; Tomasević, M; Tasić, M; Rajsić, S; Popović, A; Frontasyeva, M V; Lierhagen, S; Steinnes, E

2009-11-15

To clarify the peculiarities of trace element accumulation in moss bags technique (active biomonitoring), samples of the moss Sphagnum girgensohnii Rusow were exposed in bags with and without irrigation for 15 days up to 5 months consequently in the semi-urban area of Belgrade (Serbia) starting from July 2007. The accumulation capacity for 49 elements determined by ICP-MS in wet and dry moss bags was compared. The concentration of some elements, i.e. Al, V, Cr, Fe, Zn, As, Se, Sr, Pb, and Sm increased continuously with exposure time in both dry and wet moss bags, whereas concentration of Na, Cl, K, Mn, Rb, Cs, and Ta decreased. Irrigation of moss resulted in a higher accumulation capacity for most of the elements, especially for Cr, Zn, As, Se, Br, and Sr. Principal component analysis was performed on the datasets of element concentrations in wet and dry moss bags for source identification. Results of the factor analysis were similar but not identical in the two cases due to possible differences in element accumulation mechanisms.

Quantification of trace elements and speciation of iron in atmospheric particulate matter

NASA Astrophysics Data System (ADS)

Upadhyay, Nabin

Trace metal species play important roles in atmospheric redox processes and in the generation of oxidants in cloud systems. The chemical impact of these elements on atmospheric and cloud chemistry is dependent on their occurrence, solubility and speciation. First, analytical protocols have been developed to determine trace elements in particulate matter samples collected for carbonaceous analysis. The validated novel protocols were applied to the determination of trace elements in particulate samples collected in the remote marine atmosphere and urban areas in Arizona to study air pollution issues. The second part of this work investigates on solubility and speciation in environmental samples. A detailed study on the impact of the nature and strength of buffer solutions on solubility and speciation of iron lead to a robust protocol, allowing for comparative measurements in matrices representative of cloud water conditions. Application of this protocol to samples from different environments showed low iron solubility (less than 1%) in dust-impacted events and higher solubility (5%) in anthropogenically impacted urban samples. In most cases, Fe(II) was the dominant oxidation state in the soluble fraction of iron. The analytical protocol was then applied to investigate iron processing by fogs. Field observations showed that only a small fraction (1%) of iron was scavenged by fog droplets for which each of the soluble and insoluble fraction were similar. A coarse time resolution limited detailed insights into redox cycling within fog system. Overall results suggested that the major iron species in the droplets was Fe(1I) (80% of soluble iron). Finally, the occurrence and sources of emerging organic pollutants in the urban atmosphere were investigated. Synthetic musk species are ubiquitous in the urban environment (less than 5 ng m-3) and investigations at wastewater treatment plants showed that wastewater aeration basins emit a substantial amount of these species to the atmosphere.

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

Ehleringer, James; Randerson, James; Lai, Chun-Ta

The objective of the proposed research was to collect data and develop models to improve our understanding of the role of drought and fire impacts on the terrestrial carbon cycle in the western US, including impacts associated with urban systems as they impacted regional carbon cycles. Using data we collected and a synthesis of other measurements, we developed new ways (a) to evaluate the representation of drought stress and fire emissions in the Community Land Model, (b) to model net ecosystem exchange combining ground level atmospheric observations with boundary layer theory, (c) to model upstream impacts of fire and fossilmore » fuel emissions on atmospheric carbon dioxide observations, and (d) to model carbon dioxide observations within urban systems and at the urban-wildland interfaces of forest ecosystems.« less

Community Violence Exposure and Adolescent Substance Use: Does Monitoring and Positive Parenting Moderate Risk in Urban Communities?

ERIC Educational Resources Information Center

Lee, Rosalyn

2012-01-01

This study investigates whether monitoring and positive parenting moderate the relationship between community violence exposure (CVE) and youth substance use. Analyses utilized a subsample (N = 2197) of a cross-sectional, ethnically diverse, urban school district sample. Dependent variables were any past year alcohol or drug use (AOD) and binge…

Why Is Nature Beneficial?: The Role of Connectedness to Nature

ERIC Educational Resources Information Center

Mayer, F. Stephan; Frants, Cynthia McPherson; Bruehlman-Senecal, Emma; Dolliver, Kyffin

2009-01-01

Three studies examine the effects of exposure to nature on positive affect and ability to reflect on a life problem. Participants spent 15 min walking in a natural setting (Studies 1, 2, & 3), an urban setting (Study 1), or watching videos of natural and urban settings (Studies 2 & 3). In all three studies, exposure to nature increased…

Mass size distribution of particle-bound water

NASA Astrophysics Data System (ADS)

Canepari, S.; Simonetti, G.; Perrino, C.

2017-09-01

The thermal-ramp Karl-Fisher method (tr-KF) for the determination of PM-bound water has been applied to size-segregated PM samples collected in areas subjected to different environmental conditions (protracted atmospheric stability, desert dust intrusion, urban atmosphere). This method, based on the use of a thermal ramp for the desorption of water from PM samples and the subsequent analysis by the coulometric KF technique, had been previously shown to differentiate water contributes retained with different strength and associated to different chemical components in the atmospheric aerosol. The application of the method to size-segregated samples has revealed that water showed a typical mass size distribution in each one of the three environmental situations that were taken into consideration. A very similar size distribution was shown by the chemical PM components that prevailed during each event: ammonium nitrate in the case of atmospheric stability, crustal species in the case of desert dust, road-dust components in the case of urban sites. The shape of the tr-KF curve varied according to the size of the collected particles. Considering the size ranges that better characterize the event (fine fraction for atmospheric stability, coarse fraction for dust intrusion, bi-modal distribution for urban dust), this shape is coherent with the typical tr-KF shape shown by water bound to the chemical species that predominate in the same PM size range (ammonium nitrate, crustal species, secondary/combustion species - road dust components).

Critical Evaluation of Air-Liquid Interface Exposure Devices for In Vitro Assessment of Atmospheric Pollutants

EPA Science Inventory

Exposure of cells to atmospheric pollutants at the air-liquid interface (ALI) is a more realistic approach than exposures of attached cells submerged in liquid medium. However, there is still limited understanding of the ideal ALI device design features that permit reproducible a...

Synthesis of urban greenhouse gas emission estimates from the Indianapolis Flux Experiment (INFLUX)

NASA Astrophysics Data System (ADS)

Turnbull, J. C.; Davis, K. J.; Deng, A.; Lauvaux, T.; Miles, N. L.; Richardson, S.; Sarmiento, D. P.; Wu, K.; Brewer, A.; Hardesty, R. M.; McKain, K.; Sweeney, C.; Gurney, K. R.; Liang, J.; O'Keeffe, D.; Patarasuk, R.; Cambaliza, M. O. L.; Harvey, R. M.; Heimburger, A. M. F.; Shepson, P. B.; Karion, A.; Lopez-Coto, I.; Prasad, K.; Whetstone, J. R.

2016-12-01

The Indianapolis Flux Experiment (INFLUX) is testing the boundaries of our ability to use atmospheric measurements to quantify urban greenhouse gas (GHG) emissions. The project brings together high-resolution (in both space and time) inventory assessments, a multi-year record of in situ CO2, CH4and CO from tower-based and aircraft-based atmospheric measurements along with a complementary suite of 35 trace gases and isotopes from flasks collected at the same sites, and atmospheric modelling. Together, these provide high-accuracy, high-resolution, continuous monitoring of emissions of GHGs from the city. Here we synthesize the results to date, and demonstrate broad agreement amongst city-wide emission rates determined from the various top-down and bottom-up methods. We highlight the areas where ongoing efforts are reducing uncertainties in the overall flux estimation, including accurate representation of atmospheric transport, partitioning of GHG source types and the influence of background atmospheric GHG mole fractions.

Ubiquity of bisphenol A in the atmosphere.

PubMed

Fu, Pingqing; Kawamura, Kimitaka

2010-10-01

Bisphenol A (BPA) is a suspected endocrine disruptor in the environment. However, little is known about its distribution and transport in the atmosphere. Here, the concentrations of BPA in the atmospheric aerosols from urban, rural, marine, and the polar regions were measured using solvent extraction/derivatization and gas chromatography/mass spectrometry technique. The concentrations of BPA (1-17,400 pg m(-3)) ranged over 4 orders of magnitude in the world with a declining trend from the continent (except for the Antarctica) to remote sites. A positive correlation was found between BPA and 1,3,5-triphenylbenzene, a tracer for plastic burning, in urban regions, indicating that the open burning of plastics in domestic waste should be a significant emission source of atmospheric BPA. Our results suggest that the ubiquity of BPA in the atmosphere may raise a requirement for the evaluation of health effects of BPA in order to control its emission sources, for example, from plastic burning. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Detailed Chemical Characterization of Unresolved Complex Mixtures (UCM) inAtmospheric Organics: Insights into Emission Sources, Atmospheric Processing andSecondary Organic Aerosol Formation

EPA Science Inventory

Recent studies suggest that semivolatile organic compounds (SVOCs) are important precursors to secondary organic aerosol (SOA) in urban atmospheres. However, knowledge of the chemical composition of SVOCs is limited by current analytical techniques, which are typically unable to...

Importance of a Global Approach to Using Regional Models in the Assessment of Source-Receptor Relationships of Mercury

EPA Science Inventory

Regional atmospheric models simulate their pertinent processes over a limited portion of the global atmosphere. This portion of the atmosphere can be a large fraction, as in the case of continental-scale modeling, or small fraction, as in the case of urban-scale modeling. Regio...

A High Resolution Land Cover Data Product to Remove Urban Density Over-Estimation Bias for Coupled Urban-Vegetation-Atmosphere Interaction Studies

NASA Astrophysics Data System (ADS)

Shaffer, S. R.

2017-12-01

Coupled land-atmosphere interactions in urban settings modeled with the Weather Research and Forecasting model (WRF) derive urban land cover from 30-meter resolution National Land Cover Database (NLCD) products. However, within urban areas, the categorical NLCD lose information of non-urban classifications whenever the impervious cover within a grid cell is above 0%, and the current method to determine urban area over estimates the actual area, leading to a bias of urban contribution. To address this bias of urban contribution an investigation is conducted by employing a 1-meter resolution land cover data product derived from the National Agricultural Imagery Program (NAIP) dataset. Scenes during 2010 for the Central Arizona Phoenix Long Term Ecological Research (CAP-LTER) study area, roughly a 120 km x 100 km area containing metropolitan Phoenix, are adapted for use within WRF to determine the areal fraction and urban fraction of each WRF urban class. A method is shown for converting these NAIP data into classes corresponding to NLCD urban classes, and is evaluated in comparison with current WRF implementation using NLCD. Results are shown for comparisons of land cover products at the level of input data and aggregated to model resolution (1 km). The sensitivity of WRF short-term summertime pre-monsoon predictions within metropolitan Phoenix to different input data products of land cover, to method of aggregating these data to model grid scale (1 km), for the default and derived parameter values are examined with the Noah mosaic land surface scheme adapted for using these data. Issues with adapting these non-urban NAIP classes for use in the mosaic approach will also be discussed.

PM2.5, Population Exposure and Economic Effects in Urban Agglomerations of China Using Ground-Based Monitoring Data

PubMed Central

Shen, Yonglin

2017-01-01

This paper adopts the PM2.5 concentration data obtained from 1497 station-based monitoring sites, population and gross domestic product (GDP) census data, revealing population exposure and economic effects of PM2.5 in four typical urban agglomerations of China, i.e., Beijing-Tianjin-Hebei (BTH), the Yangtze River delta (YRD), the Pearl River delta (PRD), and Chengdu-Chongqing (CC). The Cokriging interpolation method was used to estimate the PM2.5 concentration from station-level to grid-level. Next, an evaluation was conducted mainly at the grid-level with a cell size of 1 × 1 km, assisted by the urban agglomeration scale. Criteria including the population-weighted mean, the cumulative percent distribution and the correlation coefficient were applied in our evaluation. The results showed that the spatial pattern of population exposure in BTH was consistent with that of PM2.5 concentration, as well as changes in elevation. The topography was also an important factor in the accumulation of PM2.5 in CC. Moreover, the most polluted urban agglomeration based on the population-weighted mean was BTH, while the least was PRD. In terms of the cumulative percent distribution, only 0.51% of the population who lived in the four urban agglomerations, and 2.33% of the GDP that was produced in the four urban agglomerations, were associated with an annual PM2.5 concentration smaller than the Chinese National Ambient Air Quality Standard of 35 µg/m3. This indicates that the majority of people live in the high air polluted areas, and economic development contributes to air pollution. Our results are supported by the high correlation between population exposure and the corresponding GDP in each urban agglomeration. PMID:28671643

Methane uptake in urban forests and lawns.

PubMed

Groffman, Peter M; Pouyat, Richard V

2009-07-15

The largest natural biological sink for the radiatively active trace gas methane (CH4) is bacteria in soils that consume CH4 as an energy and carbon source. This sink has been shown to be sensitive to nitrogen (N) inputs and alterations of soil physical conditions. Given this sensitivity, conversion of native ecosystems to urban, suburban, and exurban managed lawns thus has potential to affect regional CH4 budgets. We measured CH4 fluxes monthly from four urban forest, four rural forest and four urban lawn plots in the Baltimore, MD, metropolitan area from 2001 to 2005. Our objectives were to evaluate the effects of urban atmospheric and land use change on CH4 uptake and the importance of these changes relative to other greenhouse forcings in the urban landscape. Rural forests had a high capacity for CH4 uptake (1.68 mg m(-2) day(-1)). This capacity was reduced in urban forests (0.23 mg m(-2) day(-1)) and almost completely eliminated in lawns. Possible mechanisms for these reductions include increases in atmospheric N deposition and CO2 levels, fertilization of lawns, and alteration of soil physical conditions that influence diffusion. Although conversion of native forests to lawns had dramatic effects on CH4 uptake, these effects do not appear to be significant to statewide greenhouse gas forcing.

The Impact of Iodide-Mediated Ozone Deposition and ...

EPA Pesticide Factsheets

The air quality of many large coastal areas in the United States is affected by the confluence of polluted urban and relatively clean marine airmasses, each with distinct atmospheric chemistry. In this context, the role of iodide-mediated ozone (O3) deposition over seawater and marine halogen chemistry accounted for in both the lateral boundary conditions and coastal waters surrounding the continental U.S. is examined using the Community Multiscale Air Quality (CMAQ) model. Several nested simulations are conducted in which these halogen processes are implemented separately in the continental U.S. and hemispheric CMAQ domains, the latter providing lateral boundary conditions for the former. Overall, it is the combination of these processes within both the continental U.S. domain and from lateral boundary conditions that lead to the largest reductions in modeled surface O3 concentrations. Predicted reductions in surface O3 concentrations occur mainly along the coast where CMAQ typically has large overpredictions. These results suggest that a realistic representation of halogen processes in marine regions can improve model prediction of O3 concentrations near the coast. The National Exposure Research Laboratory (NERL) Computational Exposure Division (CED) develops and evaluates data, decision-support tools, and models to be applied to media-specific or receptor-specific problem areas. CED uses modeling-based approaches to characterize exposures, evaluate fate and

Estimating urban forest carbon sequestration potential in the southern United States using current remote sensing imagery sources

Treesearch

Krista Merry; Pete Bettinger; Jacek Siry; J. Michael Bowker

2015-01-01

With an increased interest in reducing carbon dioxide in the atmosphere, tree planting and maintenance in urban areas has become a viable option for increasing carbon sequestration. Methods for assessing the potential for planting trees within an urban area should allow for quick, inexpensive, and accurate estimations of available land using current remote sensing...

The potential of urban tree plantings to be cost effective in carbon credit markets

Treesearch

M.R. McHale; E.G. McPherson; I.C. Burke

2007-01-01

Emission trading is considered to be an economically sensitive method for reducing the concentrations of greenhouse gases, particularly carbon dioxide, in the atmosphere. There has been debate about the viability of using urban tree plantings in these markets. The main concern is whether or not urban planting projects can be cost effective options for investors. We...

Urban forestry and carbon: what the reporting protocol means to you

Treesearch

E.G. McPherson

2008-01-01

Urban forests have a role to play in reducing levels of carbon dioxide and other greenhouse gases (GHG) in the atmosphere (Abdollahi et al. 2000; Pataki et al. 2006). However, very few tree planting projects have been undertaken because of the uncertainty regarding their performance and permanence. The Urban Forest Project Reporting Protocol was developed to reduce...

Analyzing the cost effectiveness of Santiago, Chile's policy of using urban forests to improve air quality

Treesearch

Francisco J. Escobedo; John E. Wagner; David J. Nowak; Carmen Luz De la Maza; Manuel Rodriguez; Daniel E. Crane

2008-01-01

Santiago, Chile has the distinction of having among the worst urban air pollution problems in Latin America. As part of an atmospheric pollution reduction plan, the Santiago Regional Metropolitan government defined an environmental policy goal of using urban forests to remove particulate matter less than 10 µm (PM10) in the Gran...

Long-term results from an urban CO2 monitoring network

NASA Astrophysics Data System (ADS)

Ehleringer, J.; Pataki, D. E.; Lai, C.; Schauer, A.

2009-12-01

High-precision atmospheric CO2 has been monitored in several locations through the Salt Lake Valley metropolitan region of northern Utah over the past nine years. Many parts of this semi-arid grassland have transitioned into dense urban forests, supported totally by extensive homeowner irrigation practices. Diurnal changes in fossil-fuel energy uses and photosynthesis-respiration processes have resulted in significant spatial and temporal variations in atmospheric CO2. Here we present an analysis of the long-term patterns and trends in midday and nighttime CO2 values for four sites: a midvalley residential neighborhood, a midvalley non-residential neighborhood, an undeveloped valley-edge area transitioning from agriculture, and a developed valley-edge neighborhood with mixed residential and commercial activities; the neighborhoods span an elevation gradient within the valley of ~100 m. Patterns in CO2 concentrations among neighborhoods were examined relative to each other and relative to the NOAA background station, a desert site in Wendover, Utah. Four specific analyses are considered. First, we present a statistical analysis of weekday versus weekend CO2 patterns in the winter, spring, summer, and fall seasons. Second, we present a statistical analysis of the influences of high-pressure systems on the elevation of atmospheric CO2 above background levels in the winter versus summer seasons. Third, we present an analysis of the nighttime CO2 values through the year, relating these patterns to observed changes in the carbon isotope ratios of atmospheric CO2. Lastly, we examine the rate of increase in midday urban CO2 over time relative to regional and global CO2 averages to determine if the amplification of urban energy use is statistically detectable from atmospheric trace gas measurements over the past decade. These results show two important patterns. First, there is a strong weekday-weekend effect of vehicle emissions in contrast to the temperature-dependent effect of home-heating emissions on diurnal/seasonal cycles. Second, there appears to be photosynthetic drawdown of atmospheric CO2 levels during the growing season, but at a cost of significant water expenditure. To the degree that atmospheric CO2 and particulate matter levels are correlated, these results have implications for both climate and health issues.

GEONETCast Americas - Architecture

Science.gov Websites

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Reducing Health Risks from Indoor Exposures in Rapidly Developing Urban China

PubMed Central

Zhang, Yinping; Mo, Jinhan

2013-01-01

Background: Over the past two decades there has been a large migration of China’s population from rural to urban regions. At the same time, residences in cities have changed in character from single-story or low-rise buildings to high-rise structures constructed and furnished with many synthetic materials. As a consequence, indoor exposures (to pollutants with outdoor and indoor sources) have changed significantly. Objectives: We briefly discuss the inferred impact that urbanization and modernization have had on indoor exposures and public health in China. We argue that growing adverse health costs associated with these changes are not inevitable, and we present steps that could be taken to reduce indoor exposures to harmful pollutants. Discussion: As documented by China’s Ministry of Health, there have been significant increases in morbidity and mortality among urban residents over the past 20 years. Evidence suggests that the population’s exposure to air pollutants has contributed to increases in lung cancer, cardiovascular disease, pulmonary disease, and birth defects. Whether a pollutant has an outdoor or an indoor source, most exposure to the pollutant occurs indoors. Going forward, indoor exposures can be reduced by limiting the ingress of outdoor pollutants (while providing adequate ventilation with clean air), minimizing indoor sources of pollutants, updating government policies related to indoor pollution, and addressing indoor air quality during a building’s initial design. Conclusions: Taking the suggested steps could lead to significant reductions in morbidity and mortality, greatly reducing the societal costs associated with pollutant derived ill health. PMID:23665813

Estimated long-term outdoor air pollution concentrations in a cohort study

NASA Astrophysics Data System (ADS)

Beelen, Rob; Hoek, Gerard; Fischer, Paul; Brandt, Piet A. van den; Brunekreef, Bert

Several recent studies associated long-term exposure to air pollution with increased mortality. An ongoing cohort study, the Netherlands Cohort Study on Diet and Cancer (NLCS), was used to study the association between long-term exposure to traffic-related air pollution and mortality. Following on a previous exposure assessment study in the NLCS, we improved the exposure assessment methods. Long-term exposure to nitrogen dioxide (NO 2), nitrogen oxide (NO), black smoke (BS), and sulphur dioxide (SO 2) was estimated. Exposure at each home address ( N=21 868) was considered as a function of a regional, an urban and a local component. The regional component was estimated using inverse distance weighed interpolation of measurement data from regional background sites in a national monitoring network. Regression models with urban concentrations as dependent variables, and number of inhabitants in different buffers and land use variables, derived with a Geographic Information System (GIS), as predictor variables were used to estimate the urban component. The local component was assessed using a GIS and a digital road network with linked traffic intensities. Traffic intensity on the nearest road and on the nearest major road, and the sum of traffic intensity in a buffer of 100 m around each home address were assessed. Further, a quantitative estimate of the local component was estimated. The regression models to estimate the urban component explained 67%, 46%, 49% and 35% of the variances of NO 2, NO, BS, and SO 2 concentrations, respectively. Overall regression models which incorporated the regional, urban and local component explained 84%, 44%, 59% and 56% of the variability in concentrations for NO 2, NO, BS and SO 2, respectively. We were able to develop an exposure assessment model using GIS methods and traffic intensities that explained a large part of the variations in outdoor air pollution concentrations.

Active moss biomonitoring of trace elements with Sphagnum girgensohnii moss bags in relation to atmospheric bulk deposition in Belgrade, Serbia.

PubMed

Anicić, M; Tasić, M; Frontasyeva, M V; Tomasević, M; Rajsić, S; Mijić, Z; Popović, A

2009-02-01

Active biomonitoring with wet and dry moss bags was used to examine trace element atmospheric deposition in the urban area of Belgrade. The element accumulation capability of Sphagnum girgensohnii Russow was tested in relation to atmospheric bulk deposition. Moss bags were mounted for five 3-month periods (July 2005-October 2006) at three representative urban sites. For the same period monthly bulk atmospheric deposition samples were collected. The concentrations of Al, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, and Pb were determined by instrumental neutron activation analyses and atomic absorption spectrometry. Significant accumulation of most elements occurred in the exposed moss bags compared with the initial moss content. High correlations between the elements in moss and bulk deposits were found for V, Cu, As, and Ni. The enrichment factors of the elements for both types of monitor followed the same pattern at the corresponding sites.

CO Seasonal Variability and Trend over Paris Megacity Using Ground-Based QualAir FTS and Satellite IASI-MetOp Measurements

NASA Astrophysics Data System (ADS)

Te, Yao; Jeseck, Pascal; Hadji-Lazaro, Juliette

2012-11-01

In a growing world with more than 7 billion inhabitants and big emerging countries such as China, Brazil and India, emissions of anthropogenic pollutants are increasing continuously. Monitoring and control of atmospheric pollutants in megacities have become a major challenge for scientists and public health authorities in environmental research area. The QualAir platform at University Pierre et Marie Curie (UPMC), is an innovating experimental research platform dedicated to survey urban atmospheric pollution and air quality. A Bruker Optics IFS 125HR Fourier transform spectrometer belonged to the Laboratoire de Physique Moléculaire pour l'Atmosphère et l'Astrophysique (LPMAA), was adapted for ground-based atmospheric measurements. As one of the major instruments of the QualAir platform, this ground-based Fourier transform spectrometer (QualAir FTS) analyses the composition of the urban atmosphere of Paris, which is the third largest European megacity. The continuous monitoring of atmospheric pollutants is essential to improve the understanding of urban air pollution processes. Associated with a sun-tracker, the QualAir remote sensing FTS operates in solar infrared absorption and enables to monitor many trace gases, and to follow up their variability in the Ile-de-France region. Concentrations of atmospheric pollutants are retrieved by the radiative transfer model PROFFIT. These ground-based remote sensing measurements are compared to ground in-situ measurements and to satellite data from IASI-MetOp (Infrared Atmospheric Sounding Interferometer). The remote sensing total column of the carbon monoxide (CO) obtained from January 2009 to June 2012, has a seasonal variability with a maximum in April and a minimum in October. While, after 2008, the mean CO level is quite stable (no significant decrease as before 2008).

Measurement and analysis of ambient atmospheric particulate matter in urban and remote environments

NASA Astrophysics Data System (ADS)

Hagler, Gayle S. W.

Atmospheric particulate matter pollution is a challenging environmental concern in both urban and remote locations worldwide. It is intrinsically difficult to control, given numerous anthropogenic and natural sources (e.g. fossil fuel combustion, biomass burning, dust, and seaspray) and atmospheric transport up to thousands of kilometers after production. In urban regions, fine particulate matter (particles with diameters under 2.5 mum) is of special concern for its ability to penetrate the human respiratory system and threaten cardiopulmonary health. A second major impact area is climate, with particulate matter altering Earth's radiative balance through scattering and absorbing solar radiation, modifying cloud properties, and reducing surface reflectivity after deposition in snow-covered regions. While atmospheric particulate matter has been generally well-characterized in populated areas of developed countries, particulate pollution in developing nations and remote regions is relatively unexplored. This thesis characterizes atmospheric particulate matter in locations that represent the extreme ends of the spectrum in terms of air pollution-the rapidly-developing and heavily populated Pearl River Delta Region of China, the pristine and climate-sensitive Greenland Ice Sheet, and a remote site in the Colorado Rocky Mountains. In China, fine particles were studied through a year-long field campaign at seven sites surrounding the Pearl River Delta. Fine particulate matter was analyzed for chemical composition, regional variation, and meteorological impacts. On the Greenland Ice Sheet and in the Colorado Rocky Mountains, the carbonaceous fraction (organic and elemental carbon) of particulate matter was studied in the atmosphere and snow pack. Analyses included quantifying particulate chemical and optical properties, assessing atmospheric transport, and evaluating post-depositional processing of carbonaceous species in snow.

Alkylphenolic compounds and bisphenol A contamination within a heavily urbanized area: case study of Paris.

PubMed

Cladière, Mathieu; Gasperi, Johnny; Lorgeoux, Catherine; Bonhomme, Céline; Rocher, Vincent; Tassin, Bruno

2013-05-01

This study evaluates the influence of a heavily urbanized area (Paris Metropolitan area), on receiving water contamination by both bisphenol A (BPA) and alkylphenol ethoxylate (APE) biodegradation product. The study began by investigating concentrations within urban sources. In addition to the more commonly studied wastewater treatment plant effluent, wet weather urban sources (including combined sewer overflows, urban runoff, and total atmospheric fallout) were considered. The initial results highlight a significant contamination of all urban sources (from a few nanograms per liter in atmospheric fallout to several micrograms per liter in the other sources) with clearly distinguishable distribution patterns. Secondly, concentration changes along the Seine River from upstream of the Paris Metropolitan area to downstream were investigated. While the concentrations of BPA and nonylphenoxy acetic acid (NP₁EC) increase substantially due to urban sources, the 4-nonylphenol concentrations remain homogeneous along the Seine. These results suggest a broad dissemination of 4-nonylphenol at the scale of the Seine River basin. Moreover, the relationship between pollutant concentrations and Seine River flow was assessed both upstream and downstream of the Paris conurbation. Consequently, a sharp decrease in dissolved NP1EC concentrations relative to Seine River flow underscores the influence of single-point urban pollution on Seine River contamination. Conversely, dissolved 4-nonylphenol concentrations serve to reinforce the hypothesis of its widespread presence at the Seine River basin scale.

Polycyclic aromatic hydrocarbons in the urban atmospheric particulate matter in the city of Naples (Italy)

NASA Astrophysics Data System (ADS)

Caricchia, Anna Maria; Chiavarini, Salvatore; Pezza, Massimo

An investigation on PAH in the atmospheric particulate matter of the city of Naples has been carried out. Urban atmospheric particulate matter was sampled in three sampling sites (West, East and central areas of the city), whose characteristics were representative of the prevailing conditions. In each site, 24 h samplings for 7 consecutive days were performed during three sampling campaigns, in 1996-1997. The results were comparable with those reported in literature for similar investigations. Total PAH were in the range 2-130 ng m -3, with a seasonal variation (autumn/winter vs. summer) in the range 1.5-4.5. The relative contribution of diesel engines vs. gasoline fuelled engines was evidenced.

Fractional bio-accessibility: A new tool for Pb risk assessment from urban garden soils and superfund sites

USDA-ARS?s Scientific Manuscript database

Pb contamination of urban soils and its strong association with elevated blood Pb concentrations, especially in children, has raised concerns about whether gardens should be recommended for urban areas. Reliable evaluation of the potential hazard to the public from exposure to urban garden soils gr...

Observing and simulating the impact of growing urbanization on air quality and climate in the Eastern Mediterranean

NASA Astrophysics Data System (ADS)

Kanakidou, Maria; Myriokefalitakis, Stelios; Mihalopoulos, Nikos; Vrekoussis, Mihalis; Daskalakis, Nikos; Sfakianaki, Maria; Hatziannastassiou, Nikos; Im, Ulas

2016-07-01

The Mediterranean, and particularly its east basin, is a crossroad of air masses coming from Europe, Asia and Africa. Over this area, anthropogenic emissions, mainly from Europe, Balkans and the Black Sea, meet with natural emissions from Sahara (Saharan dust), vegetation and the ocean as well as from biomass burning, overall presenting a strong seasonal pattern. As a consequence of its unique location and emissions, the Mediterranean region is climatically very sensitive and often exposed to multiple stresses, such as a simultaneous water shortage and elevated air pollution exposure. During the last decades, the Eastern Mediterranean, following the general trend, has experienced a rapid growth in urbanization, including increased vehicle circulation, and industrialization, all impacting pollutant emissions in the atmosphere. Air pollution is one of the challenging environmental problems for Istanbul and Cairo megacities but also for the whole Eastern Mediterranean region. The recent financial crisis resulted in changes in human habits, energy production and subsequently air pollution. This resulted in changes in tropospheric composition that reflect changes in natural emissions and in human behavior have been detected by satellites and simulated by chemistry transport models. The results are presented and their robustness is discussed.

Status, sources, and human health risk assessment of PAHs via foliar dust from different functional areas in Nanjing, China.

PubMed

Zha, Yan; Zhang, Yin L; Tang, Jie; Sun, Kai

2018-05-12

The present study was carried out to assess and understand the potential health risk, level of contamination, composition pattern, and sources of urban foliar dust in Nanjing City with respect to polycyclic aromatic hydrocarbons (PAHs). Five urban functional areas of foliar dust were analysed and the contents of 16 priority PAHs were determined. Total PAH concentrations in foliar dust ranged from 1.77 to 19.02 μg·g -1 , with an average value of 6.98 μg·g -1 . The PAH pattern was dominated by four and five-ring PAHs (contributing > 38% of total PAHs) in all of the five functional areas. The results indicated that the combustion of fossil fuel, coal, and biomass, as well as vehicle traffic emissions were the major sources of PAHs. The estimated incremental lifetime cancer risk due to PAHs in foliar dust were 8.19 × 10 -6 , 6.63 × 10 -6 , and 9.65 × 10 -6 for childhood, adolescence and adulthood, respectively, indicating a high risk of cancer from exposure to foliar dust in Nanjing. Our results indicated that foliar dust might be a useful indicator of atmospheric PAH pollution.

Effects of urban density on carbon dioxide exchanges: Observations of dense urban, suburban and woodland areas of southern England.

PubMed

Ward, H C; Kotthaus, S; Grimmond, C S B; Bjorkegren, A; Wilkinson, M; Morrison, W T J; Evans, J G; Morison, J I L; Iamarino, M

2015-03-01

Anthropogenic and biogenic controls on the surface-atmosphere exchange of CO2 are explored for three different environments. Similarities are seen between suburban and woodland sites during summer, when photosynthesis and respiration determine the diurnal pattern of the CO2 flux. In winter, emissions from human activities dominate urban and suburban fluxes; building emissions increase during cold weather, while traffic is a major component of CO2 emissions all year round. Observed CO2 fluxes reflect diurnal traffic patterns (busy throughout the day (urban); rush-hour peaks (suburban)) and vary between working days and non-working days, except at the woodland site. Suburban vegetation offsets some anthropogenic emissions, but 24-h CO2 fluxes are usually positive even during summer. Observations are compared to estimated emissions from simple models and inventories. Annual CO2 exchanges are significantly different between sites, demonstrating the impacts of increasing urban density (and decreasing vegetation fraction) on the CO2 flux to the atmosphere. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Increased atmospheric deposition of mercury in reference lakes near major urban areas

USGS Publications Warehouse

Van Metre, P.C.

2012-01-01

Atmospheric deposition of Hg is the predominant pathway for Hg to reach sensitive ecosystems, but the importance of emissions on near-field deposition remains unclear. To better understand spatial variability in Hg deposition, mercury concentrations were analyzed in sediment cores from 12 lakes with undeveloped watersheds near to (<50 km) and remote from (>150 km) several major urban areas in the United States. Background and focusing corrected Hg fluxes and flux ratios (modern to background) in the near-urban lakes (68 ?? 6.9 ??g m -2 yr -1 and 9.8 ?? 4.8, respectively) greatly exceed those in the remote lakes (14 ?? 9.3 ??g m -2 yr -1 and 3.5 ?? 1.0) and the fluxes are strongly related to distance from the nearest major urban area (r 2 = 0.87) and to population and Hg emissions within 50-100 km of the lakes. Comparison to monitored wet deposition suggests that dry deposition is a major contributor of Hg to lakes near major urban areas. ?? 2011 Elsevier Ltd. All rights reserved.

Urban gardens: Lead exposure, recontamination mechanisms, and implications for remediation design

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

Clark, Heather F.; Hausladen, Debra M.; Brabander, Daniel J.

2008-07-15

Environmental lead contamination is prevalent in urban areas where soil represents a significant sink and pathway of exposure. This study characterizes the speciation of lead that is relevant to local recontamination and to human exposure in the backyard gardens of Roxbury and Dorchester, MA, USA. One hundred forty-one backyard gardens were tested by X-ray fluorescence, and 81% of gardens have lead levels above the US EPA action limit of 400 {mu}g/g. Raised gardening beds are the in situ exposure reduction method used in the communities to promote urban gardening. Raised beds were tested for lead and the results showed thatmore » the lead concentration increased from an initial range of 150{+-}40 {mu}g/g to an average of 336 {mu}g/g over 4 years. The percent distribution of lead in the fine grain soil (<100 {mu}m) and the trace metal signature of the raised beds support the conclusion that the mechanism of recontamination is wind-transported particles. Scanning electron microscopy and sequential extraction were used to characterize the speciation of lead, and the trace metal signature of the fine grain soil in both gardens and raised gardening beds is characteristic of lead-based paint. This study demonstrates that raised beds are a limited exposure reduction method and require maintenance to achieve exposure reduction goals. An exposure model was developed based on a suite of parameters that combine relevant values from the literature with site-specific quantification of exposure pathways. This model suggests that consumption of homegrown produce accounts for only 3% of children's daily exposure of lead while ingestion of fine grained soil (<100 {mu}m) accounts for 82% of the daily exposure. This study indicates that urban lead remediation on a yard-by-yard scale requires constant maintenance and that remediation may need to occur on a neighborhood-wide scale.« less

Urban gardens: lead exposure, recontamination mechanisms, and implications for remediation design.

PubMed

Clark, Heather F; Hausladen, Debra M; Brabander, Daniel J

2008-07-01

Environmental lead contamination is prevalent in urban areas where soil represents a significant sink and pathway of exposure. This study characterizes the speciation of lead that is relevant to local recontamination and to human exposure in the backyard gardens of Roxbury and Dorchester, MA, USA. One hundred forty-one backyard gardens were tested by X-ray fluorescence, and 81% of gardens have lead levels above the US EPA action limit of 400 microg/g. Raised gardening beds are the in situ exposure reduction method used in the communities to promote urban gardening. Raised beds were tested for lead and the results showed that the lead concentration increased from an initial range of 150+/-40 microg/g to an average of 336 microg/g over 4 years. The percent distribution of lead in the fine grain soil (<100 microm) and the trace metal signature of the raised beds support the conclusion that the mechanism of recontamination is wind-transported particles. Scanning electron microscopy and sequential extraction were used to characterize the speciation of lead, and the trace metal signature of the fine grain soil in both gardens and raised gardening beds is characteristic of lead-based paint. This study demonstrates that raised beds are a limited exposure reduction method and require maintenance to achieve exposure reduction goals. An exposure model was developed based on a suite of parameters that combine relevant values from the literature with site-specific quantification of exposure pathways. This model suggests that consumption of homegrown produce accounts for only 3% of children's daily exposure of lead while ingestion of fine grained soil (<100 microm) accounts for 82% of the daily exposure. This study indicates that urban lead remediation on a yard-by-yard scale requires constant maintenance and that remediation may need to occur on a neighborhood-wide scale.

Impacts of compact growth and electric vehicles on future air quality and urban exposures may be mixed.

PubMed

Yu, Haofei; Stuart, Amy L

2017-01-15

'Smart' growth and electric vehicles are potential solutions to the negative impacts of worldwide urbanization on air pollution and health. However, the effects of planning strategies on distinct types of pollutants, and on human exposures, remain understudied. The goal of this work was to investigate the potential impacts of alternative urban designs for the area around Tampa, Florida USA, on emissions, ambient concentrations, and exposures to oxides of nitrogen (NO x ), 1,3-butadiene, and benzene. We studied three potential future scenarios: sprawling growth, compact growth, and 100% vehicle fleet electrification with compact growth. We projected emissions in the seven-county region to 2050 based on One Bay regional visioning plan data. We estimated pollutant concentrations in the county that contains Tampa using the CALPUFF dispersion model. We applied residential population projections to forecast acute (highest hour) and chronic (annual average) exposure. The compact scenario was projected to result in lower regional emissions of all pollutants than sprawl, with differences of -18%, -3%, and -14% for NO x , butadiene, and benzene, respectively. Within Hillsborough County, the compact form also had lower emissions, concentrations, and exposures than sprawl for NO x (-16%/-5% for acute/chronic exposures, respectively), but higher exposures for butadiene (+41%/+30%) and benzene (+21%/+9%). The addition of complete vehicle fleet electrification to the compact scenario mitigated these in-county increases for the latter pollutants, lowering predicted exposures to butadiene (-25%/-39%) and benzene (-5%/-19%), but also resulted in higher exposures to NO x (+81%/+30%) due to increased demand on power plants. These results suggest that compact forms may have mixed impacts on exposures and health. 'Smart' urban designs should consider multiple pollutants and the diverse mix of pollutant sources. Cleaner power generation will also likely be needed to support aggressive adoption of electric vehicles. Copyright © 2016 Elsevier B.V. All rights reserved.

Exposure to Community Violence and Protective and Risky Contexts among Low Income Urban African American Adolescents: A Prospective Study

ERIC Educational Resources Information Center

Goldner, Jonathan; Peters, Tracy L.; Richards, Maryse H.; Pearce, Steven

2011-01-01

This study examined protective and risky companionship and locations for exposure to community violence among African American young adolescents living in high crime, urban areas. The Experience Sampling Method (ESM), an in vivo data collection method, was employed to gather information from 233 students (62% female) over 3 years, beginning in the…

Short-Chain Chlorinated Paraffins in Zurich, Switzerland--Atmospheric Concentrations and Emissions.

PubMed

Diefenbacher, Pascal S; Bogdal, Christian; Gerecke, Andreas C; Glüge, Juliane; Schmid, Peter; Scheringer, Martin; Hungerbühler, Konrad

2015-08-18

Short-chain chlorinated paraffins (SCCPs) are of concern due to their potential for adverse health effects, bioaccumulation, persistence, and long-range transport. Data on concentrations of SCCPs in urban areas and underlying emissions are still scarce. In this study, we investigated the levels and spatial distribution of SCCPs in air, based on two separate, spatially resolved sampling campaigns in the city of Zurich, Switzerland. SCCP concentrations in air ranged from 1.8 to 17 ng·m(-3) (spring 2011) and 1.1 to 42 ng·m(-3) (spring 2013) with medians of 4.3 and 2.7 ng·m(-3), respectively. Both data sets show that atmospheric SCCP levels in Zurich can vary substantially and may be influenced by a number of localized sources within this urban area. Additionally, continuous measurements of atmospheric concentrations performed at one representative sampling site in the city center from 2011 to 2013 showed strong seasonal variations with high SCCP concentrations in summer and lower levels in winter. A long-term dynamic multimedia environmental fate model was parametrized to simulate the seasonal trends of SCCP concentrations in air and to back-calculate urban emissions. Resulting annual SCCP emissions in the city of Zurich accounted for 218-321 kg, which indicates that large SCCP stocks are present in urban areas of industrialized countries.

Impact of the Dubai Coastline Intensive Urbanization on the Atmosphere Employing MODIS Data (2001-2014)

NASA Astrophysics Data System (ADS)

Elhacham, Emily; Alpert, Pinhas

2017-04-01

Over the last 20 years Dubai landscape has dramatically changed - artificial islands have been constructed as well as residential and industrial facilities along with roads systems. This rapid and massive construction placed Dubai urban growth rate at the top of the global list. Here, we investigate the impact of those constructions on the local atmosphere, both in land and sea based on MODIS data. It was found that, over the tested time period, temperature decreases and albedo increases were observed in the sea area of the artificial islands. In land, albedo decreases along with temperature increases of up to 2C were observed in the areas along the coast where intensive constructions occurred. In addition, the coast of Dubai was found to have urban heat island characteristics, where the urban center point at Deira area exhibits higher temperature than surrounding points along the coast. Nonetheless, the largest temperature trends were observed in the coastal area in between Palm Jumeirah and Palm Jebel Ali, where massive construction was performed during the tested time frame. Reference: E.Elhacham and P. Alpert ,"Impact of coastline-intensive anthropogenic activities on the atmosphere from moderate resolution imaging spectroradiometer (MODIS) data in Dubai (2001-2014)", Earth's Future, 4, 2016.

Representation of urban surfaces of tropical and subtropical cities in numerical models of the atmosphere

NASA Astrophysics Data System (ADS)

Karam, H. A.; Pereira Filho, A. J.

This work proposes a numerical representation of the urban surface for tropical and subtropical cities in numerical models of atmosphere. A typical tropical metropolis is São Paulo City, SP, Brazil, that presents a neighborhood area characterized by an uncompleted urbanization and where the public services are limited in attend the needs of the population. The suburban area of São Paulo city presents an occupation that is distinguished of the typical occupation of the European cities because: (1) it occurs in risk areas, i.e., over inclined terrain or potentially flooded areas on the borders of rivers; (2) the buildings are made with some cheap row material mixed with traditional materials; (3) the distribution of short and long wave radiation is conditioned by the inclination of the terrain, geometry of the buildings, materials and population density; (4) the exclusion of many common living areas; (5) intense or free thermal convection is found over the urban surface on the diurnal time with impact in the Atmospheric Boundary Layer dynamics; (6) high levels of airborne pollutants are found; etc. The proposed numerical scheme is designed to contribute with the current tools used to forecast the impact of convective precipitations in the risk areas of São Paulo City.

Communicating Climate Hazards Information in the Urban Community to the Public

NASA Astrophysics Data System (ADS)

McCalla, M. R.

2004-12-01

Climate simulations are predicting an overall warming of the atmosphere due to greenhouse gases. For example, CO2 allows sunlight to reach the earth and warm its surface, but it prevents a portion of this surface heat from escaping the atmosphere. This greenhouse effect can result in higher mean atmospheric temperatures near the Earth's surface. If these predictions are correct, changes in temperature can increase the power demand to cool urban building structures (homes, schools, offices, storage facilities, etc.). Similarly, the regional and seasonal temperature fluctuations due to climate oscillations (El Nino, for example) may also increase the power demand for heating and cooling. A warming climate (or cooling climate, for that matter) can also affect the available water for drinking, irrigation, and generating power, all of which impact the viability and sustainability of the urban community. Additionally, urban areas are expanding. Consequently, the distance between city and wildlands is decreasing. The wildland-urban interface often stresses biodiversity, forestation, and the urban area's ability to respond adequately to such climate-induced hazards as forest fires, flooding, and coastal erosion. Thus climate has an impact on humans and vice versa. How can scientists communicate the impact of climate on the urban community? What is the best way to communicate the information so that the public can (1) be informed and (2) make informed decisions? How well is the nexus between climate science and impacts on and benefits to decision makers understood? What is the best way to fully exploit that connection so that the public can develop intervention measures to support the urban community's response to climatic impacts? The Office of the Federal Coordinator for Meteorological Services and Supporting Research (OFCM) is an interdepartmental office established in response to Public Law 87-843 with the express purpose of ensuring the effective use of federal meteorological resources by leading the systematic coordination of operational weather and climate requirements, services, products, capabilities, information, modeling, and supporting research among the federal agencies. Toward that end, the OFCM, in partnership with the Department of Homeland Security Science and Technology Directorate, is sponsoring a September 2004 forum on urban meteorology. The theme of the forum is "Information to Improve Community Responses to Urban Atmospheric Hazards, Weather Events, and Climate." Forum participants and speakers will come from both the public and private sectors, as well as the academic community. The output of the forum will be to specifically answer such questions as (1) how will emerging technologies help communicate risks more effectively to the urban community; (2) how can education, outreach, and training be more effective in eliciting an appropriate public response; and (3) what methods are needed to better communicate and disseminate climate information to the public? The communication recommendations stemming from the urban meteorology forum will be shared with AGU conference participants.

Exposure to maltreatment and urban violence in children working on the streets in São Paulo, Brazil: factors associated with street work.

PubMed

Mello, Andrea F; Maciel, Mariana R; Fossaluza, Victor; Paula, Cristiane S de; Grassi-Oliveira, Rodrigo; Cavalcante-Nóbrega, Luciana P; Cividanes, Giuliana C; Soussumi, Yusaku; Soussumi, Sonia P; Perissinotti, Dirce N M; Bordin, Isabel A; Mello, Marcelo F; Mari, Jair J

2014-09-01

To quantitatively study the exposure to childhood maltreatment and urban violence in children from families with at least one child working on the streets and to investigate the relationship between these factors and street work. Families who participated in a nongovernmental organization (NGO) program to eliminate child labor were included. Data concerning sociodemographic characteristics, punishment methods used in the family environment against the children, five types of abuse and neglect perpetrated by the caregivers, urban violence exposure and family functioning were collected. The sample included 126 children who were working on the streets and 65 siblings who were not working on the streets. Caregivers reported high levels of severe physical punishment. The children reported high levels of abuse and neglect, and high levels of urban violence exposure. The families showed a predominance of dysfunctional and unsatisfactory relationships. A multiple logistic regression model showed that age older than 12 years and severe physical punishment at home were associated with street work. Interventions to decrease the risk of child street work should be family-focused and should aim to reduce violence in the family environment.

Remote Sensing of Urban Thermal Landscape Characteristics and Their Affects on Local and Regional Meteorology and Air Quality: An Overview of NASA EOS-IDS Project Atlanta

NASA Technical Reports Server (NTRS)

Quattrochi, Dale A.; Luvall, Jeffrey C.; Estes, Maurice G., Jr.

1999-01-01

As an entity, the city is a manifestation of human "management" of the land. The act of city-building, however, drastically alters the biophysical environment, which ultimately, impacts local and regional land-atmosphere energy exchange processes. Because of the complexity of both the urban landscape and the attendant energy fluxes that result from urbanization, remote sensing offers the only real way to synoptically quantify these processes. One of the more important land-atmosphere fluxes that occurs over cities relates to the way that thermal energy is partitioned across the heterogeneous urban landscape. The individual land cover and surface material types that comprise the city, such as pavements and buildings, each have their own thermal energy regimes. As the collective urban landscape, the individual thermal energy responses from specific surfaces come together to form the urban heat island phenomena, which prevails as a dome of elevated air temperatures over cities. Although the urban heat island has been known to exist for well over 150 years, it is not understood how differences in thermal energy responses for land covers across the city interact to produce this phenomenon, or how the variability in thermal energy responses from different surface types drive its development. Additionally, it can be hypothesized that as cities grow in size through time, so do their urban heat islands. The interrelationships between urban sprawl and the respective growth of the urban heat island, however, have not been investigated. Moreover, little is known of the consequential effects of urban growth, land cover change, and the urban heat island as they impact local and regional meteorology and air quality.

Validation of the Martilli's Urban Boundary Layer Scheme with measurements from two mid-latitude European cities

NASA Astrophysics Data System (ADS)

Hamdi, R.; Schayes, G.

2005-07-01

The Martilli's urban parameterization scheme is improved and implemented in a mesoscale model in order to take into account the typical effects of a real city on the air temperature near the ground and on the surface exchange fluxes. The mesoscale model is run on a single column using atmospheric data and radiation recorded above roof level as forcing. Here, the authors validate the Martilli's urban boundary layer scheme using measurements from two mid-latitude European cities: Basel, Switzerland and Marseilles, France. For Basel, the model performance is evaluated with observations of canyon temperature, surface radiation, and energy balance fluxes obtained during the Basel urban boundary layer experiment (BUBBLE). The results show that the urban parameterization scheme is able to reproduce the generation of the Urban Heat Island (UHI) effect over urban area and represents correctly most of the behavior of the fluxes typical of the city center of Basel, including the large heat uptake by the urban fabric and the positive sensible heat flux at night. For Marseilles, the model performance is evaluated with observations of surface temperature, canyon temperature, surface radiation, and energy balance fluxes collected during the field experiments to constrain models of atmospheric pollution and transport of emissions (ESCOMPTE) and its urban boundary layer (UBL) campaign. At both urban sites, vegetation cover is less than 20%, therefore, particular attention was directed to the ability of the Martilli's urban boundary layer scheme to reproduce the observations for the Marseilles city center, where the urban parameters and the synoptic forcing are totally different from Basel. Evaluation of the model with wall, road, and roof surface temperatures gave good results. The model correctly simulates the net radiation, canyon temperature, and the partitioning between the turbulent and storage heat fluxes.

The Urban Fabric of the City as Its Affects Thermal Energy Responses Derived from Remote Sensing Data

NASA Technical Reports Server (NTRS)

Quattrochi, Dale A.; Luvall, Jeffrey C.; Estes, Maurice G., Jr.

2000-01-01

The physical geography of the city affects numerous aspects of its interlinked biophysical, social, and land-atmosphere characteristics - those attributes that come together to form the total urban environment. One approach to studying the multitude of interactions that occur as a result of urbanization is to view the city from a systems ecology perspective, where energy and material cycle into and out of the urban milieu. Thus, the urban ecosystem is synergistic in linking land, air, water, and living organisms in a vast network of interrelated physical, human, and biological process. Given the number and the shear complexity of the exchanges and, ultimately, their effects, that occur within the urban environment, we are focusing our research on looking at how the morphology or urban fabric of the city, drives thermal energy exchanges across the urban landscape. The study of thermal energy attributes for different cities provides insight into how thermal fluxes and characteristics are partitioned across the city landscape in response to each city's morphology. We are using thermal infrared remote sensing data obtained at a high spatial resolution from aircraft, along with satellite data, to identify and quantify thermal energy characteristics for 4 U.S. cities: Atlanta, GA, Baton Rouge, LA, Salt Lake City, UT, and Sacramento, CA. Analysis of how thermal energy is spatially distributed across the urban landscapes for these cities provides a unique perspective for understanding how the differing morphology of cities forces land-atmosphere exchanges, such as the urban heat island effect, as well as related meteorological and air quality interactions. Keyword: urban ecosystems, remote sensing, urban heat island

Inhalation of Photochemically Altered Urban Mixtures Depresses Cardiac Function in Mice

EPA Science Inventory

Rationale: Epidemiological studies have indicated an association between urban air pollution exposure and cardiovascular morbidity and mortality. The present study was designed to evaluate the cardiac effects of inhaled photochemical products in urban mixtures in a murine model. ...

Contributions to Global Augmented Compound Urban Heat Extreme (ACUTE) from Climate Change and the Urban Heat Island Effect

NASA Astrophysics Data System (ADS)

Huang, K.

2017-12-01

Over the next decades, climate change is projected to increase the intensity and frequency of extreme heat events (EHEs). The severity and periodicity of these hazards are likely to be further compounded by stronger urban heat island (UHI) effects as the world continues to urbanize. However, there is little known about how greenhouse gases (GHG) induced changes in EHE will interact with UHI, and what this will mean for the exposure of urban populations to high temperature. This work aims to fill this knowledge gap by combining a mesoscale meteorological model (Weather Research Forecasting, WRF) with a global urban expansion forecast, to generate spatially explicit projections of compound urban temperature extremes through 2050. These global projections include all the urban areas in developing world. The respective contributions from GHG-induced climate change, the UHI effect, and their interaction vary across different types of urban areas. The resulting compound heat extremes will be more intense and frequent in emerging Asian and African mega urban regions, located in tropical/subtropical climates, due to their unprecedented sizes and the significantly reduced evaporation. Previous studies neglecting the interaction between global climate change and regional UHI effect have underestimated exposure to heat extremes in urban areas.

Atmospheric trace element concentrations in total suspended particles near Paris, France

NASA Astrophysics Data System (ADS)

Ayrault, Sophie; Senhou, Abderrahmane; Moskura, Mélanie; Gaudry, André

2010-09-01

To evaluate today's trace element atmospheric concentrations in large urban areas, an atmospheric survey was carried out for 18 months, from March 2002 to September 2003, in Saclay, nearby Paris. The total suspended particulate matter (TSP) was collected continuously on quartz fibre filters. The TSP contents were determined for 36 elements (including Ag, Bi, Mo and Sb) using two analytical methods: Instrumental Neutron Activation Analysis (INAA) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The measured concentrations were in agreement within the uncertainties with the certified values for the polycarbonate reference material filter SRM-2783 (National Institute for Standard Technology NIST, USA). The measured concentrations were significantly lower than the recommended atmospheric concentrations. In 2003, the Pb atmospheric level at Saclay was 15 ng/m 3, compared to the 500 ng/m 3 guideline level and to the 200 ng/m 3 observed value in 1994. The typical urban background TSP values of 1-2, 0.2-1, 4-6, 10-30 and 3-5 ng/m 3 for As, Co, Cr, Cu and Sb, respectively, were inferred from this study and were compared with the literature data. The typical urban background TSP concentrations could not be realised for Cd, Pb and Zn, since these air concentrations are highly influenced by local features. The Zn concentrations and Zn/Pb ratio observed in Saclay represented a characteristic fingerprint of the exceptionally large extent of zinc-made roofs in Paris and its suburbs. The traffic-related origin of Ba, Cr, Cu, Pb and Sb was demonstrated, while the atmospheric source(s) of Ag was not identified.

Effects of sun exposure on 25(OH) vitamin D concentration in urban and rural women in Malaysia.

PubMed

Nurbazlin, Musa; Chee, Winnie Siew Swee; Rokiah, Pendek; Tan, Alexander Tong Boon; Chew, Yee Yean; Nusaibah, Abd Rahman Siti; Chan, Siew Pheng

2013-01-01

Ultraviolet B sunlight exposure is a primary source of vitamin D. There have been reports of low vitamin D status amongst the Malaysian population despite it being a tropical country. This study was conducted to determine the influence of sun exposure on 25(OH)D concentrations in urban and rural women in Malaysia and factors predicting 25(OH)D concentrations. Women aged above 45 years were recruited from urban (n=107) and rural areas (n=293). Subjects were interviewed regarding their outdoor activities and usual outdoor attire over the previous week. 25(OH)D concentrations were analyzed using the vitamin D3 (25-OH) electrochemiluminescence immunoassay. Median (Q1-Q3) age of the participants was 57 (53-61) years old. Median (Q1-Q3) 25(OH)D concentration of rural women was significantly higher [69.5 (59.0-79.1) nmol/L] compared to urban women [31.9 (26.1- 45.5) nmol/L] (p<0.001). Rural women spent more time in the sun compared to urban women (7.83 (3.67-14.7) vs 2.92 (1.17-4.92) hours, p<0.001), although the fraction of body surface area (BSA) exposed to sunlight was significantly higher in the urban group [0.21 (0.21-0.43) vs 0.12 (0.07-0.17), p<0.001]. The calculated sun index (hours of sun exposure per week × fraction of BSA) was significantly higher in rural [0.89 (0.42-1.83)] compared to urban women [0.72 (0.26-1.28)], p=0.018. In the stepwise linear regression, rural dwelling increased the serum 25(OH)D by 31.74 nmol/L and 25(OH)D concentrations increased by 1.93 nmol/L for every unit increment in sun index. Urban women in Malaysia had significantly lower vitamin D status compared to rural women. Rural dwelling and sun index were key factors influencing vitamin D status in Malaysian women.

Urbanization and Daily Exposure to Biomass Fuel Smoke Both Contribute to Chronic Bronchitis Risk in a Population with Low Prevalence of Daily Tobacco Smoking.

PubMed

Miele, Catherine H; Jaganath, Devan; Miranda, J Jaime; Bernabe-Ortiz, Antonio; Gilman, Robert H; Johnson, Caroline M; Diette, Gregory B; Wise, Robert A; Checkley, William

2016-01-01

Risk factors beyond tobacco smoking associated with chronic bronchitis are not well understood. We sought to describe the prevalence and risk factors of chronic bronchitis across four distinct settings in Peru with overall low prevalence of tobacco smoking yet varying degrees of urbanization, daily exposure to biomass fuel smoke and living at high altitude. We analyzed data of 2,947 participants from rural and urban Puno, Lima and Tumbes including spirometry, blood samples, anthropometry and administered questionnaires about respiratory symptoms. We used multivariable Poisson regression to assess biologic, socioeconomic and environmental risk factors associated with chronic bronchitis. Overall prevalence of chronic bronchitis was 5.9% (95%CI 5.1%-6.9%) with variation by setting: prevalence was lower in semi-urban Tumbes (1.3%) vs. highly urbanized Lima (8.9%), urban Puno (7.0%) and rural Puno (7.8%; p < 0.001). Chronic bronchitis was more common among participants with vs. without COPD based on FEV1/FVC< LLN (12.1% vs 5.6%, p < 0.01) and it was associated with increased reporting of dyspnea on exertion (p < 0.001), hospitalization (p = 0.003) and workdays missed due to respiratory symptoms (p < 0.001). Older age (Prevalence ratio [PR] = 1.23 for each 10-years of age, 95%CI 1.09-1.40) past history of asthma (PR = 2.87, 95%CI 1.80-4.56), urbanization (PR = 3.34, 95%CI 2.18-5.11) and daily exposure to biomass fuel smoke (PR = 2.00, 95%CI 1.30-3.07) were all associated with chronic bronchitis. We found important variations in the prevalence of chronic bronchitis across settings. Prevalence increased with both urbanization and with daily exposure to biomass fuel smoke. Having chronic bronchitis was also associated with worse patient-centered outcomes including dyspnea, hospitalization and missed workdays.

Aircraft observations of the urban CO2 dome in London and calculated daytime CO2 fluxes at the urban-regional scale

NASA Astrophysics Data System (ADS)

Font, Anna; Morgui, Josep Anton; Grimmond, Sue; Barratt, Benjamin

2013-04-01

Traffic, industry and energy production and consumption within urban boundaries emit great amounts of CO2 into the atmosphere, creating an urban increment of CO2 mixing ratios compared to the surrounding rural atmosphere. Monitoring CO2 within these 'urban domes' has been proposed as a means to evaluate the effectiveness of policies aiming to mitigate and reduce CO2 urban emissions (CMEGGE, 2010). London is the biggest urban conurbation in Western Europe with more than 8 million inhabitants, and it emitted roughly 45000 ktn CO2 in 2010 (DECC, 2012). In order to develop and implement observational strategies to measure the contribution of urban areas into the global carbon cycle, two airborne surveys were deployed using the Natural and Environment Research Council - Airborne Research and Survey Facility (NERC-ARSF). High frequency measurements of atmospheric CO2, O3, particles and meteorological variables were taken over London in October 2011 and July 2012. CO2 mixing ratios were measured by a Non-Dispersive IR instrument developed by AOS. In July 2012, a Cavity Ring-Down Spectroscopy (CDRS) instrument developed by PICARRO was deployed measuring CO2, CH4 and water vapour at 1Hz resolution. The objectives of the campaigns were to measure the CO2 dome over London and to calculate CO2 emissions at the urban-regional-scale. London was crossed by two transects (SW-NE and SSE-NNW) at an altitude of 360 m and vertical profiles up to 2000 m were carried out to characterize the structure of the atmosphere. Aircraft measurements allowed observation on how CO2 domes were shaped by meteorological conditions. In October 2011, the mean CO2 mixing ratio measured in London was on average 2 ppmv higher than the suburban measurements within the boundary layer. However, under low wind speeds, the CO2 mixing ratio in the urban mixing ratio peaked in central London (>10 ppmv) and decreased towards the city boundaries. Under windy conditions, the structure of the urban dome was dispersed downwind, with peak concentrations displaced from the urban centre along the main wind direction. The urban-regional surface CO2 flux was calculated for four days in October 2011 by either the Integrative Mass Boundary Layer (IMBL) or the Column Integration method (CIM), dependent on meteorological conditions. The diurnal CO2 flux in London obtained from the aircraft observations ranged from 36 to 71 μmol CO2 m-2 s-1 during the day time. This compared well with continuous measurements of CO2 exchange by an eddy-covariance system located in central London. The day-to-day variability observed in the calculated CO2 fluxes responded to the spatial variability of the influence area and emissions that observations were sensitive to. This study provides an example how aircraft surveys in urban areas can be used to estimate CO2 surface fluxes at the urban-regional scale. It also presents an important cross-validation of two independent measurement-based methods to infer the contribution of urban areas to climate change in terms of CO2 emissions that complement bottom-up emissions inventories. References Committee on Methods for Estimating Greenhouse Gas Emissions (2010), The National Academia Press. DECC (2012), http://www.decc.gov.uk/en/content/cms/statistics/indicators/ni186/ni186.aspx

The influence of nondisclosure on the mental health of urban African-American adolescents exposed to community violence.

PubMed

Dinizulu, Sonya Mathies; Grant, Kathryn E; McIntosh, Jeanne M

2014-01-01

African-American youth residing in urban poverty have been shown to be at increased risk for exposure to violence and internalizing symptoms, but there has been little investigation of moderating processes that might attenuate or exacerbate this association. The current study examined nondisclosure as a possible moderator of the association between community violence and internalizing symptoms with a sample of 152 low-income urban African-American early adolescents using hierarchical regression analyses. Results revealed that nondisclosure for relationship reasons (e.g., adults could not be trusted to provide needed support) moderated the association between exposure to community violence and internalizing symptoms. Unexpectedly, however, results of simple effects analyses revealed a stronger association between exposure to violence and internalizing symptoms for youth who disclosed more to adults. Although unexpected, this pattern builds upon prior research indicating that adult-child relationships are compromised within the context of urban poverty and that protective factors may lose their power under conditions of extreme stress.

Unexpectedly high mortality in Pacific herring embryos exposed to the 2007 Cosco Busan oil spill in San Francisco Bay.

PubMed

Incardona, John P; Vines, Carol A; Anulacion, Bernadita F; Baldwin, David H; Day, Heather L; French, Barbara L; Labenia, Jana S; Linbo, Tiffany L; Myers, Mark S; Olson, O Paul; Sloan, Catherine A; Sol, Sean; Griffin, Frederick J; Menard, Karl; Morgan, Steven G; West, James E; Collier, Tracy K; Ylitalo, Gina M; Cherr, Gary N; Scholz, Nathaniel L

2012-01-10

In November 2007, the container ship Cosco Busan released 54,000 gallons of bunker fuel oil into San Francisco Bay. The accident oiled shoreline near spawning habitats for the largest population of Pacific herring on the west coast of the continental United States. We assessed the health and viability of herring embryos from oiled and unoiled locations that were either deposited by natural spawning or incubated in subtidal cages. Three months after the spill, caged embryos at oiled sites showed sublethal cardiac toxicity, as expected from exposure to oil-derived polycyclic aromatic compounds (PACs). By contrast, embryos from the adjacent and shallower intertidal zone showed unexpectedly high rates of tissue necrosis and lethality unrelated to cardiotoxicity. No toxicity was observed in embryos from unoiled sites. Patterns of PACs at oiled sites were consistent with oil exposure against a background of urban sources, although tissue concentrations were lower than expected to cause lethality. Embryos sampled 2 y later from oiled sites showed modest sublethal cardiotoxicity but no elevated necrosis or mortality. Bunker oil contains the chemically uncharacterized remains of crude oil refinement, and one or more of these unidentified chemicals likely interacted with natural sunlight in the intertidal zone to kill herring embryos. This reveals an important discrepancy between the resolving power of current forensic analytical chemistry and biological responses of keystone ecological species in oiled habitats. Nevertheless, we successfully delineated the biological impacts of an oil spill in an urbanized coastal estuary with an overlapping backdrop of atmospheric, vessel, and land-based sources of PAC pollution.

Land cover and air pollution are associated with asthma hospitalisations: A cross-sectional study.

PubMed

Alcock, Ian; White, Mathew; Cherrie, Mark; Wheeler, Benedict; Taylor, Jonathon; McInnes, Rachel; Otte Im Kampe, Eveline; Vardoulakis, Sotiris; Sarran, Christophe; Soyiri, Ireneous; Fleming, Lora

2017-12-01

There is increasing policy interest in the potential for vegetation in urban areas to mitigate harmful effects of air pollution on respiratory health. We aimed to quantify relationships between tree and green space density and asthma-related hospitalisations, and explore how these varied with exposure to background air pollution concentrations. Population standardised asthma hospitalisation rates (1997-2012) for 26,455 urban residential areas of England were merged with area-level data on vegetation and background air pollutant concentrations. We fitted negative binomial regression models using maximum likelihood estimation to obtain estimates of asthma-vegetation relationships at different levels of pollutant exposure. Green space and gardens were associated with reductions in asthma hospitalisation when pollutant exposures were lower but had no significant association when pollutant exposures were higher. In contrast, tree density was associated with reduced asthma hospitalisation when pollutant exposures were higher but had no significant association when pollutant exposures were lower. We found differential effects of natural environments at high and low background pollutant concentrations. These findings can provide evidence for urban planning decisions which aim to leverage health co-benefits from environmental improvements. Copyright © 2017 Elsevier Ltd. All rights reserved.

Los Angeles megacity: a high-resolution land–atmosphere modelling system for urban CO 2 emissions

DOE PAGES

Feng, Sha; Lauvaux, Thomas; Newman, Sally; ...

2016-07-22

Megacities are major sources of anthropogenic fossil fuel CO 2 (FFCO 2) emissions. The spatial extents of these large urban systems cover areas of 10 000 km 2 or more with complex topography and changing landscapes. We present a high-resolution land–atmosphere modelling system for urban CO 2 emissions over the Los Angeles (LA) megacity area. The Weather Research and Forecasting (WRF)-Chem model was coupled to a very high-resolution FFCO 2 emission product, Hestia-LA, to simulate atmospheric CO 2 concentrations across the LA megacity at spatial resolutions as fine as ~1 km. We evaluated multiple WRF configurations, selecting one that minimizedmore » errors in wind speed, wind direction, and boundary layer height as evaluated by its performance against meteorological data collected during the CalNex-LA campaign (May–June 2010). Our results show no significant difference between moderate-resolution (4 km) and high-resolution (1.3 km) simulations when evaluated against surface meteorological data, but the high-resolution configurations better resolved planetary boundary layer heights and vertical gradients in the horizontal mean winds. We coupled our WRF configuration with the Vulcan 2.2 (10 km resolution) and Hestia-LA (1.3 km resolution) fossil fuel CO 2 emission products to evaluate the impact of the spatial resolution of the CO 2 emission products and the meteorological transport model on the representation of spatiotemporal variability in simulated atmospheric CO 2 concentrations. We find that high spatial resolution in the fossil fuel CO 2 emissions is more important than in the atmospheric model to capture CO 2 concentration variability across the LA megacity. Finally, we present a novel approach that employs simultaneous correlations of the simulated atmospheric CO 2 fields to qualitatively evaluate the greenhouse gas measurement network over the LA megacity. Spatial correlations in the atmospheric CO 2 fields reflect the coverage of individual measurement sites when a statistically significant number of sites observe emissions from a specific source or location. We conclude that elevated atmospheric CO 2 concentrations over the LA megacity are composed of multiple fine-scale plumes rather than a single homogenous urban dome. Furthermore, we conclude that FFCO 2 emissions monitoring in the LA megacity requires FFCO 2 emissions modelling with ~1 km resolution because coarser-resolution emissions modelling tends to overestimate the observational constraints on the emissions estimates.« less

Los Angeles megacity: a high-resolution land–atmosphere modelling system for urban CO 2 emissions

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

Feng, Sha; Lauvaux, Thomas; Newman, Sally

Megacities are major sources of anthropogenic fossil fuel CO 2 (FFCO 2) emissions. The spatial extents of these large urban systems cover areas of 10 000 km 2 or more with complex topography and changing landscapes. We present a high-resolution land–atmosphere modelling system for urban CO 2 emissions over the Los Angeles (LA) megacity area. The Weather Research and Forecasting (WRF)-Chem model was coupled to a very high-resolution FFCO 2 emission product, Hestia-LA, to simulate atmospheric CO 2 concentrations across the LA megacity at spatial resolutions as fine as ~1 km. We evaluated multiple WRF configurations, selecting one that minimizedmore » errors in wind speed, wind direction, and boundary layer height as evaluated by its performance against meteorological data collected during the CalNex-LA campaign (May–June 2010). Our results show no significant difference between moderate-resolution (4 km) and high-resolution (1.3 km) simulations when evaluated against surface meteorological data, but the high-resolution configurations better resolved planetary boundary layer heights and vertical gradients in the horizontal mean winds. We coupled our WRF configuration with the Vulcan 2.2 (10 km resolution) and Hestia-LA (1.3 km resolution) fossil fuel CO 2 emission products to evaluate the impact of the spatial resolution of the CO 2 emission products and the meteorological transport model on the representation of spatiotemporal variability in simulated atmospheric CO 2 concentrations. We find that high spatial resolution in the fossil fuel CO 2 emissions is more important than in the atmospheric model to capture CO 2 concentration variability across the LA megacity. Finally, we present a novel approach that employs simultaneous correlations of the simulated atmospheric CO 2 fields to qualitatively evaluate the greenhouse gas measurement network over the LA megacity. Spatial correlations in the atmospheric CO 2 fields reflect the coverage of individual measurement sites when a statistically significant number of sites observe emissions from a specific source or location. We conclude that elevated atmospheric CO 2 concentrations over the LA megacity are composed of multiple fine-scale plumes rather than a single homogenous urban dome. Furthermore, we conclude that FFCO 2 emissions monitoring in the LA megacity requires FFCO 2 emissions modelling with ~1 km resolution because coarser-resolution emissions modelling tends to overestimate the observational constraints on the emissions estimates.« less

Integration of population mobility in the evaluation of air quality measures on local and regional scales

NASA Astrophysics Data System (ADS)

Dhondt, S.; Beckx, C.; Degraeuwe, B.; Lefebvre, W.; Kochan, B.; Bellemans, T.; Int Panis, L.; Macharis, C.; Putman, K.

2012-11-01

By focussing on air pollutant concentration levels only, the variation in population mobility is not taken into account when assessing the exposure. Transportation policies have an impact on both concentration levels and mobility patterns. The impact of a fuel price increase policy on population exposure to elemental carbon (EC) was evaluated and compared to the base scenario (current situation), taking into account time-activity patterns - including time in commute. We assessed the effect on exposure of both the change in concentrations and whereabouts. The decrease in exposure due to the fuel price increase using residential information only was limited to areas near highways and urban centres. Integrating population movement, exposures to EC were higher and the decrease in exposure was no longer limited to areas near traffic hotspots. For inhabitants of urban areas, the exposure integrating time-activity patterns was more similar to the residential exposure, as they spent more time in their own neighbourhood. For people living further away from traffic hotspots, the estimated impact of the policy was higher than expected for residential exposure. These people profited both from the higher decrease in concentrations at their work/shop/leisure destinations in more urban areas and, as they have to travel longer, also had a larger gain from the high decrease in concentrations during transport. Therefore, the impact of changing concentrations is underestimated when using residential exposure only. These results show the importance of taking into activity-travel patterns when planning future actions.

Inflammatory Cytokines and White Blood Cell Counts ...

EPA Pesticide Factsheets

Epidemiological observations of urban inhalation exposures to diesel exhaust (DE) and ozone (O3) have shown pre-clinical cardiopulmonary responses in humans. Identifying the key biological mechanisms that initiate these health bioindicators is difficult due to variability in environmental exposure in time and from person to person. Previously, environmentally controlled human exposure chambers have been used to study DE and O3 dose-response patterns separately, but investigation of co-exposures has not been performed under controlled conditions. Because a mixture is a more realistic exposure scenario for the general public, in this study we investigate the relationships of urban levels of urban-level DE exposure (300 μg/m3), O3 (0.3 ppm), DE + O3 co-exposure, and innate immune system responses. Fifteen healthy human volunteers were studied for changes in ten inflammatory cytokines (interleukins 1β, 2, 4, 5, 8, 10, 12p70 and 13, IFN-γ, and TNF-α) and counts of three white blood cell types (lymphocytes, monocytes, and neutrophils) following controlled exposures to DE, O3, and DE+O3. The results show subtle cytokines responses to the diesel-only and ozone-only exposures, and that a more complex (possibly synergistic) relationship exists in the combination of these two exposures with suppression of IL-5, IL-12p70, IFN-γ, and TNF-α that persists up to 22-hours for IFN-γ and TNF-α. The white blood cell differential counts showed significant monocyte and lympho

A study of the health effects of bicycling in an urban atmosphere

DOT National Transportation Integrated Search

1977-10-14

This report analyzes data on the health effects of bicycling in an urban environment through intensive study of ten healthy male subjects bicycling or driving in systematically varied conditions in the streets of Washington, D.C. Evaluation criteria ...

Modeling spatial effects of PM{sub 2.5} on term low birth weight in Los Angeles County

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

Coker, Eric, E-mail: cokerer@onid.orst.edu; Ghosh, Jokay; Jerrett, Michael

Air pollution epidemiological studies suggest that elevated exposure to fine particulate matter (PM{sub 2.5}) is associated with higher prevalence of term low birth weight (TLBW). Previous studies have generally assumed the exposure–response of PM{sub 2.5} on TLBW to be the same throughout a large geographical area. Health effects related to PM{sub 2.5} exposures, however, may not be uniformly distributed spatially, creating a need for studies that explicitly investigate the spatial distribution of the exposure–response relationship between individual-level exposure to PM{sub 2.5} and TLBW. Here, we examine the overall and spatially varying exposure–response relationship between PM{sub 2.5} and TLBW throughout urbanmore » Los Angeles (LA) County, California. We estimated PM{sub 2.5} from a combination of land use regression (LUR), aerosol optical depth from remote sensing, and atmospheric modeling techniques. Exposures were assigned to LA County individual pregnancies identified from electronic birth certificates between the years 1995-2006 (N=1,359,284) provided by the California Department of Public Health. We used a single pollutant multivariate logistic regression model, with multilevel spatially structured and unstructured random effects set in a Bayesian framework to estimate global and spatially varying pollutant effects on TLBW at the census tract level. Overall, increased PM{sub 2.5} level was associated with higher prevalence of TLBW county-wide. The spatial random effects model, however, demonstrated that the exposure–response for PM{sub 2.5} and TLBW was not uniform across urban LA County. Rather, the magnitude and certainty of the exposure–response estimates for PM{sub 2.5} on log odds of TLBW were greatest in the urban core of Central and Southern LA County census tracts. These results suggest that the effects may be spatially patterned, and that simply estimating global pollutant effects obscures disparities suggested by spatial patterns of effects. Studies that incorporate spatial multilevel modeling with random coefficients allow us to identify areas where air pollutant effects on adverse birth outcomes may be most severe and policies to further reduce air pollution might be most effective. - Highlights: • We model the spatial dependency of PM{sub 2.5} effects on term low birth weight (TLBW). • PM{sub 2.5} effects on TLBW are shown to vary spatially across urban LA County. • Modeling spatial dependency of PM{sub 2.5} health effects may identify effect 'hotspots'. • Birth outcomes studies should consider the spatial dependency of PM{sub 2.5} effects.« less

A framework for emissions source apportionment in industrial areas: MM5/CALPUFF in a near-field application.

PubMed

Ghannam, K; El-Fadel, M

2013-02-01

This paper examines the relative source contribution to ground-level concentrations of carbon monoxide (CO), nitrogen dioxide (NO2), and PM10 (particulate matter with an aerodynamic diameter < 10 microm) in a coastal urban area due to emissions from an industrial complex with multiple stacks, quarrying activities, and a nearby highway. For this purpose, an inventory of CO, oxide of nitrogen (NO(x)), and PM10 emissions was coupled with the non-steady-state Mesoscale Model 5/California Puff Dispersion Modeling system to simulate individual source contributions under several spatial and temporal scales. As the contribution of a particular source to ground-level concentrations can be evaluated by simulating this single-source emissions or otherwise total emissions except that source, a set of emission sensitivity simulations was designed to examine if CALPUFF maintains a linear relationship between emission rates and predicted concentrations in cases where emitted plumes overlap and chemical transformations are simulated. Source apportionment revealed that ground-level releases (i.e., highway and quarries) extended over large areas dominated the contribution to exposure levels over elevated point sources, despite the fact that cumulative emissions from point sources are higher. Sensitivity analysis indicated that chemical transformations of NO(x) are insignificant, possibly due to short-range plume transport, with CALPUFF exhibiting a linear response to changes in emission rate. The current paper points to the significance of ground-level emissions in contributing to urban air pollution exposure and questions the viability of the prevailing paradigm of point-source emission reduction, especially that the incremental improvement in air quality associated with this common abatement strategy may not accomplish the desirable benefit in terms of lower exposure with costly emissions capping. The application of atmospheric dispersion models for source apportionment helps in identifying major contributors to regional air pollution. In industrial urban areas where multiple sources with different geometry contribute to emissions, ground-level releases extended over large areas such as roads and quarries often dominate the contribution to ground-level air pollution. Industrial emissions released at elevated stack heights may experience significant dilution, resulting in minor contribution to exposure at ground level. In such contexts, emission reduction, which is invariably the abatement strategy targeting industries at a significant investment in control equipment or process change, may result in minimal return on investment in terms of improvement in air quality at sensitive receptors.

Impact of urban air pollution on the allergenicity of Aspergillus fumigatus conidia: Outdoor exposure study supported by laboratory experiments.

PubMed

Lang-Yona, Naama; Shuster-Meiseles, Timor; Mazar, Yinon; Yarden, Oded; Rudich, Yinon

2016-01-15

Understanding the chemical interactions of common allergens in urban environments may help to decipher the general increase in susceptibility to allergies observed in recent decades. In this study, asexual conidia of the allergenic mold Aspergillus fumigatus were exposed to air pollution under natural (ambient) and controlled (laboratory) conditions. The allergenic activity was measured using two immunoassays and supported by a protein mass spectrometry analysis. The allergenicity of the conidia was found to increase by 2-5 fold compared to the control for short exposure times of up to 12h (accumulated exposure of about 50 ppb NO2 and 750 ppb O3), possibly due to nitration. At higher exposure times, the allergenicity increase lessened due to protein deamidation. These results indicate that during the first 12h of exposure, the allergenic potency of the fungal allergen A. fumigatus in polluted urban environments is expected to increase. Additional work is needed in order to determine if this behavior occurs for other allergens. Copyright © 2015 Elsevier B.V. All rights reserved.

A CROSS-PROVINCE ANALYSIS OF URBAN AND RURAL INDOOR PM2.5 EXPOSURE IN CHINA USING TIME USE SURVEY

NASA Astrophysics Data System (ADS)

Shimada, Yoko; Guo, Minna; Kurata, Gakuji; Matsuoka, Yuzuru

In developing countries in Asia and other parts of the world, most energy sources used in the home are solid fuels such as coal and biomass (firewood, crop residue and animal dung). Particulate matter 2.5, consisting of particles with an aerodynamic diameter of 2.5 um or less, produced through combustion of these fuels inside the residence for cooking and heating has an adverse impact on people's health. We estimated PM2.5 exposure concentration in indoor microenvironment for each cohort of urban and rural area in ten provinces of China, using statistical data on time use survey and domestic energy consumption. The study found that, in each province, the exposure concentration in rural area was higher than in urban area, unemployed women between the ages of 60 and 64 had the highest estimate for exposure concentration at 3027 μg/m3. The study also found that the exposure concentration for individual cohorts in each province was greatly affected by people's use of time indoors, fuel consumption such as coal or biomass and floor space.

Methane source identification in Boston, Massachusetts using isotopic and ethane measurements

NASA Astrophysics Data System (ADS)

Down, A.; Jackson, R. B.; Plata, D.; McKain, K.; Wofsy, S. C.; Rella, C.; Crosson, E.; Phillips, N. G.

2012-12-01

Methane has substantial greenhouse warming potential and is the principle component of natural gas. Fugitive natural gas emissions could be a significant source of methane to the atmosphere. However, the cumulative magnitude of natural gas leaks is not yet well constrained. We used a combination of point source measurements and ambient monitoring to characterize the methane sources in the Boston urban area. We developed distinct fingerprints for natural gas and multiple biogenic methane sources based on hydrocarbon concentration and isotopic composition. We combine these data with periodic measurements of atmospheric methane and ethane concentration to estimate the fractional contribution of natural gas and biogenic methane sources to the cumulative urban methane flux in Boston. These results are used to inform an inverse model of urban methane concentration and emissions.

Impact of meteorological inflow uncertainty on tracer transport and source estimation in urban atmospheres

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

Lucas, Donald D.; Gowardhan, Akshay; Cameron-Smith, Philip

2015-08-08

Here, a computational Bayesian inverse technique is used to quantify the effects of meteorological inflow uncertainty on tracer transport and source estimation in a complex urban environment. We estimate a probability distribution of meteorological inflow by comparing wind observations to Monte Carlo simulations from the Aeolus model. Aeolus is a computational fluid dynamics model that simulates atmospheric and tracer flow around buildings and structures at meter-scale resolution. Uncertainty in the inflow is propagated through forward and backward Lagrangian dispersion calculations to determine the impact on tracer transport and the ability to estimate the release location of an unknown source. Ourmore » uncertainty methods are compared against measurements from an intensive observation period during the Joint Urban 2003 tracer release experiment conducted in Oklahoma City.« less

Characterization and Low-Dimensional Modeling of Urban Fluid Flow

DTIC Science & Technology

2014-10-06

4 2 Wind Tunnel , Apparatus and Data Processing 7 2.1 Modelling of the Atmospheric Boundary Layer...was demonstrated. Most notably, wind tunnel experiments were performed at a number of different angles of incidence, providing for the first time a...Coceal and Belcher [2004] developed an urban canopy model for mean winds in urban areas that compares well with data from wind tunnel experiments

Quantifying the role of urban forests in removing atmospheric carbon dioxide

Treesearch

Rowan A. Rowntree; David J. Nowak

1991-01-01

Urban land in the United States currently occupies about 69 million acres with an estimated average crown cover of 28% and an estimated tree biomass of about 27 tons/acre. This structure suggests that the current total urban forest carbon storage in the United States is approximately 800 million tons with an estimated annual net carbon storage of around 6.5 million...

Seasonal variations of dissolved organic carbon in precipitation over urban and forest sites in central Poland.

PubMed

Siudek, Patrycja; Frankowski, Marcin; Siepak, Jerzy

2015-07-01

Spatial and temporal variability of carbon species in rainwater (bulk deposition) was studied for the first time at two sites located in urban area of Poznań City and protected woodland area (Jeziory), in central Poland, between April and December 2013. The mean concentration of total carbon (TC) for the first site was 5.86 mg L(-1), whereas for the second, 5.21 mg L(-1). Dissolved organic carbon (DOC) concentration accounted for, on average, 87 and 91 % of total carbon in precipitation at urban and non-urban sites, respectively. Significant changes in TC concentrations in rainwater were observed at both sites, indicating that atmospheric transformation, transport, and removal mechanisms of carbonaceous particles were affected by seasonal fluctuations in biogenic/anthropogenic emission and meteorological conditions (i.e., precipitation height and type, atmospheric transport). During the warm season, the DOC concentration in rainwater was mostly influenced by mixed natural and anthropogenic sources. In contrast, during the cold season, the DOC concentration significantly increased mainly as a result of anthropogenic activities, i.e., intensive coal combustion, domestic wood burning, high-temperature processes, etc. In addition, during the winter measurements, significant differences in mean DOC concentration (Kruskal-Wallis test, p < 0.05) were determined for rain, mixed rain-snow, and snow samples. It was found that rainwater TOC concentration measured in Poznań and Jeziory reflected a combination of local, regional, and distant sources. Backward trajectory analysis showed that air masses advected from polluted regions in western Europe largely affect the DOC amount in rainwater, both at urban and non-urban sites. These data imply that carbonaceous compounds are of crucial importance in atmospheric chemistry and should be considered as an important parameter while considering wet deposition, reactions with different substances, especially over polluted environments.

Modelling Pollutant Dispersion in a Street Network

NASA Astrophysics Data System (ADS)

Salem, N. Ben; Garbero, V.; Salizzoni, P.; Lamaison, G.; Soulhac, L.

2015-04-01

This study constitutes a further step in the analysis of the performances of a street network model to simulate atmospheric pollutant dispersion in urban areas. The model, named SIRANE, is based on the decomposition of the urban atmosphere into two sub-domains: the urban boundary layer, whose dynamics is assumed to be well established, and the urban canopy, represented as a series of interconnected boxes. Parametric laws govern the mass exchanges between the boxes under the assumption that the pollutant dispersion within the canopy can be fully simulated by modelling three main bulk transfer phenomena: channelling along street axes, transfers at street intersections, and vertical exchange between street canyons and the overlying atmosphere. Here, we aim to evaluate the reliability of the parametrizations adopted to simulate these phenomena, by focusing on their possible dependence on the external wind direction. To this end, we test the model against concentration measurements within an idealized urban district whose geometrical layout closely matches the street network represented in SIRANE. The analysis is performed for an urban array with a fixed geometry and a varying wind incidence angle. The results show that the model provides generally good results with the reference parametrizations adopted in SIRANE and that its performances are quite robust for a wide range of the model parameters. This proves the reliability of the street network approach in simulating pollutant dispersion in densely built city districts. The results also show that the model performances may be improved by considering a dependence of the wind fluctuations at street intersections and of the vertical exchange velocity on the direction of the incident wind. This opens the way for further investigations to clarify the dependence of these parameters on wind direction and street aspect ratios.

Modeling Transport of Turbulent Fluxes in a Heterogeneous Urban Canopy Using a Spatially Explicit Energy Balance

NASA Astrophysics Data System (ADS)

Moody, M.; Bailey, B.; Stoll, R., II

2017-12-01

Understanding how changes in the microclimate near individual plants affects the surface energy budget is integral to modeling land-atmosphere interactions and a wide range of near surface atmospheric boundary layer phenomena. In urban areas, the complex geometry of the urban canopy layer results in large spatial deviations of turbulent fluxes further complicating the development of models. Accurately accounting for this heterogeneity in order to model urban energy and water use requires a sub-plant level understanding of microclimate variables. We present analysis of new experimental field data taken in and around two Blue Spruce (Picea pungens) trees at the University of Utah in 2015. The test sites were chosen in order study the effects of heterogeneity in an urban environment. An array of sensors were placed in and around the conifers to quantify transport in the soil-plant-atmosphere continuum: radiative fluxes, temperature, sap fluxes, etc. A spatial array of LEMS (Local Energy Measurement Systems) were deployed to obtain pressure, surrounding air temperature and relative humidity. These quantities are used to calculate the radiative and turbulent fluxes. Relying on measurements alone is insufficient to capture the complexity of microclimate distribution as one reaches sub-plant scales. A spatially-explicit radiation and energy balance model previously developed for deciduous trees was extended to include conifers. The model discretizes the tree into isothermal sub-volumes on which energy balances are performed and utilizes incoming radiation as the primary forcing input. The radiative transfer component of the model yields good agreement between measured and modeled upward longwave and shortwave radiative fluxes. Ultimately, the model was validated through an examination of the full energy budget including radiative and turbulent fluxes through isolated Picea pungens in an urban environment.

Characterization, source identification and apportionment of selected metals in TSP in an urban atmosphere.

PubMed

Shah, Munir H; Shaheen, N; Jaffar, M

2006-03-01

To understand the metal distribution characteristics in the atmosphere of urban Islamabad, total suspended particulate (TSP) samples were collected on daily 12 h basis, at Quaid-i-Azam University campus, using high volume sampler. The TSP samples were treated with HNO(3)/HClO(4) based wet digestion method for the quantification of eight selected metals; Fe, Zn, Pb, Mn, Cr, Co, Ni and Cd by FAAS method. The monitoring period ran from June 2001 to January 2002, with a total of 194 samples collected on cellulose filters. Effects of different meteorological conditions such as temperature, relative humidity, wind speed and wind direction on selected metal levels were interpreted by means of multivariate statistical approach. Enhanced metal levels for Fe (930 ng/m(3)), Zn (542 ng/m(3)) and Pb (210 ng/m(3)) were found on the mean scale while Mn, Cr, Co and Ni emerged as minor contributors. Statistical correlation study was also conducted and a strong correlation was observed between Pb-Cr (r=0.611). The relative humidity showed some significant influence on atmospheric metal distribution while other meteorological parameters showed weak relationship with TSP metal levels. Regarding the origin of sources of heavy metals in TSP, the statistical procedure identified three source profiles; automobile emissions, industrial/metallurgical units, and natural soil dust. The metal levels were also compared with those reported for other parts of the world which showed that the metal levels in urban atmosphere of Islamabad are in exceedence than those of European industrial and urban sites while comparable with some Asian sites.

Geospatial methods provide timely and comprehensive urban forest information

Treesearch

Kathleen T. Ward; Gary R. Johnson

2007-01-01

Urban forests are unique and highly valued resources. However, trees in urban forests are often under greater stress than those in rural or undeveloped areas due to soil compaction, restricted growing spaces, high temperatures, and exposure to air and water pollution. In addition, conditions change more quickly in urban as opposed to rural and undeveloped settings....

Adolescent Tobacco Use in Urban Versus Rural Areas of the United States: The Influence of Tobacco Control Policy Environments.

PubMed

Pesko, Michael F; Robarts, Adam M T

2017-07-01

Adults and adolescents who reside in rural areas of the United States are traditionally more likely to be tobacco users. This urban-rural disparity remains largely unexplained and, more recently, it is unclear what impact the emergence of electronic cigarettes (e-cigarettes) has had on adolescent tobacco use in urban and rural areas. Our objective is to evaluate the influence of sociodemographics and tobacco control policy environments on adolescent tobacco use in urban versus rural areas, as well as to identify the effect of e-cigarettes on traditional patterns of urban-rural tobacco use. This study analyzes repeated cross-sectional data from the National Youth Tobacco Survey for the years 2011-2014. We estimate the associations between rural residence, cigarette taxes, tobacco advertisement exposure, and ease of access to tobacco with six tobacco use outcomes: current (past 30-day) use of cigarettes, e-cigarettes, cigars, smokeless tobacco, multiple tobacco products, and any tobacco. E-cigarette use among urban youths aged 11-17 years in the United States increased from .82% in 2011 to 8.62% in 2014 (p < .001). Tobacco advertisement exposure was significantly positively associated with all current tobacco use outcomes (p < .001) except for e-cigarettes. Our predictors account for approximately 40% of the difference in urban-rural cigarette use. Sociodemographics, cigarette taxes, and tobacco advertisement exposure are significant predictors of adolescent tobacco use in the United States but do not entirely explain urban-rural disparities. In addition, e-cigarettes appear to be rapidly changing traditional patterns of tobacco use, particularly in urban areas. Copyright © 2017 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Spatial and Temporal Dynamics in Air Pollution Exposure Assessment

PubMed Central

Dias, Daniela; Tchepel, Oxana

2018-01-01

Analyzing individual exposure in urban areas offers several challenges where both the individual’s activities and air pollution levels demonstrate a large degree of spatial and temporal dynamics. This review article discusses the concepts, key elements, current developments in assessing personal exposure to urban air pollution (seventy-two studies reviewed) and respective advantages and disadvantages. A new conceptual structure to organize personal exposure assessment methods is proposed according to two classification criteria: (i) spatial-temporal variations of individuals’ activities (point-fixed or trajectory based) and (ii) characterization of air quality (variable or uniform). This review suggests that the spatial and temporal variability of urban air pollution levels in combination with indoor exposures and individual’s time-activity patterns are key elements of personal exposure assessment. In the literature review, the majority of revised studies (44 studies) indicate that the trajectory based with variable air quality approach provides a promising framework for tackling the important question of inter- and intra-variability of individual exposure. However, future quantitative comparison between the different approaches should be performed, and the selection of the most appropriate approach for exposure quantification should take into account the purpose of the health study. This review provides a structured basis for the intercomparing of different methodologies and to make their advantages and limitations more transparent in addressing specific research objectives. PMID:29558426

GEONETCast Americas - Architecture

Science.gov Websites

Oceanic and Atmospheric Administration whose goal is to enable enhanced dissemination, application, and Management; Public Health Surveillance; Sustainable Urban Development and Water Resources Management. Privacy Act Statement Copyright 2008 © NOAA. All rights reserved. the National Oceanic and Atmospheric

ONE ATMOSPHERE MODELING FOR AIR QUALITY: BUILDING PARTNERSHIPS THAT TRANSITION RESEARCH INTO APPLICATIONS

EPA Science Inventory

The Community Miultiscale Air Quality (CMAQ) modeling system is a "one atmosphere" chemical transport model that simulates the transport and fate of air pollutants from urban to continental scales and from daily to annual time intervals.

DART: Recent Advances in Remote Sensing Data Modeling With Atmosphere, Polarization, and Chlorophyll Fluorescence

NASA Technical Reports Server (NTRS)

Gastellu-Etchegorry, Jean-Phil; Lauret, Nicolas; Yin, Tiangang; Landier, Lucas; Kallel, Abdelaziz; Malenovsky, Zbynek; Bitar, Ahmad Al; Aval, Josselin; Benhmida, Sahar; Qi, Jianbo;

Quantification of fossil fuel CO2 emissions at the urban scale: Results from the Indianapolis Flux Project (INFLUX)

NASA Astrophysics Data System (ADS)

Turnbull, J. C.; Cambaliza, M. L.; Sweeney, C.; Karion, A.; Newberger, T.; Tans, P. P.; Lehman, S.; Davis, K. J.; Miles, N. L.; Richardson, S.; Lauvaux, T.; Shepson, P.; Gurney, K. R.; Song, Y.; Razlivanov, I. N.

2012-12-01

Emissions of fossil fuel CO2 (CO2ff) from anthropogenic sources are the primary driver of observed increases in the atmospheric CO2 burden, and hence global warming. Quantification of the magnitude of fossil fuel CO2 emissions is vital to improving our understanding of the global and regional carbon cycle, and independent evaluation of reported emissions is essential to the success of any emission reduction efforts. The urban scale is of particular interest, because ~75% CO2ff is emitted from urban regions, and cities are leading the way in attempts to reduce emissions. Measurements of 14CO2 can be used to determine CO2ff, yet existing 14C measurement techniques require laborious laboratory analysis and measurements are often insufficient for inferring an urban emission flux. This presentation will focus on how 14CO2 measurements can be combined with those of more easily measured ancillary tracers to obtain high resolution CO2ff mixing ratio estimates and then infer the emission flux. A pilot study over Sacramento, California showed strong correlations between CO2ff and carbon monoxide (CO) and demonstrated an ability to quantify the urban flux, albeit with large uncertainties. The Indianapolis Flux Project (INFLUX) aims to develop and assess methods to quantify urban greenhouse gas emissions. Indianapolis was chosen as an ideal test case because it has relatively straightforward meteorology; a contained, isolated, urban region; and substantial and well-known fossil fuel CO2 emissions. INFLUX incorporates atmospheric measurements of a suite of gases and isotopes including 14C from light aircraft and from a network of existing tall towers surrounding the Indianapolis urban area. The recently added CO2ff content is calculated from measurements of 14C in CO2, and then convolved with atmospheric transport models and ancillary data to estimate the urban CO2ff emission flux. Significant innovations in sample collection include: collection of hourly averaged samples to remove short term atmospheric variability; and direct measurement of the background signal from towers immediately upwind of the urban area and from the boundary layer. We find that CO2ff and other anthropogenic trace gases are consistently enhanced at a tower site downwind of the city. Measurements made directly over or very close to the urban area show only weak correlations between CO2ff and trace gases associated with combustion, likely because the urban plume is not yet well mixed. Total CO2 is also consistently enhanced in the downwind samples, even in summer. In winter, total CO2 enhancement is slightly higher than the fossil fuel CO2 enhancement, in agreement with Indiana's requirement for 10% bioethanol use in gasoline. This result implies that the enhancement in total CO2 can be used to infer CO2ff emissions for Indianapolis during winter. We therefore use the high resolution in situ total CO2 measurements in a simple mass balance model to estimate the urban CO2ff emissions. An initial comparison shows a ~20% difference between the top-down and bottom-up methods.

Impacts of future urban expansion on summer climate and heat-related human health in eastern China.

PubMed

Cao, Qian; Yu, Deyong; Georgescu, Matei; Wu, Jianguo; Wang, Wei

2018-03-01

China is the largest and most rapidly urbanizing nation in the world, and is projected to add an additional 200 million city dwellers by the end of 2030. While this rapid urbanization will lead to vast expansion of built-up areas, the possible climate effect and associated human health impact remain poorly understood. Using a coupled urban-atmospheric model, we first examine potential effects of three urban expansion scenarios to 2030 on summer climate in eastern China. Our simulations indicate extensive warming up to 5°C, 3°C, and 2°C in regard to low- (>0%), high- (>75%), and 100% probability urban growth scenarios, respectively. The partitioning of available energy largely explains the changes in 2-m air temperatures, and increased sensible heat flux with higher roughness length of the underlying urban surface is responsible for the increase of nighttime planetary boundary layer height. In the extreme case (the low-probability expansion pathway), the agglomeration of impervious surfaces substantially reduces low-level atmospheric moisture, consequently resulting in large-scale precipitation reduction. However, the effect of near-surface warming far exceeds that of moisture reduction and imposes non-negligible thermal loads on urban residents. Our study, using a scenario-based approach that accounts for the full range of urban growth uncertainty by 2030, helps better evaluate possible regional climate effects and associated human health outcomes in the most rapidly urbanizing areas of China, and has practical implications for the development of sustainable urban regions that are resilient to changes in both mean and extreme conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

HIV-Related Risk Behaviors, Perceptions of Risk, HIV Testing, and Exposure to Prevention Messages and Methods among Urban American Indians and Alaska Natives

ERIC Educational Resources Information Center

Lapidus, Jodi A.; Bertolli, Jeanne; McGowan, Karen; Sullivan, Patrick

2006-01-01

The goal of this study was to describe HIV risk behaviors, perceptions, testing, and prevention exposure among urban American Indians and Alaska Natives (AI/AN). Interviewers administered a questionnaire to participants recruited through anonymous peer-referral sampling. Chi-square tests and multiple logistic regression were used to compare HIV…

Model Urbanization Strategy: Summaries, Recommendations and Requirements

EPA Science Inventory

The urban canopy (UC), the layer of the atmosphere between the ground and the top of the highest buildings, is the region where people live and human activities take place. Because of this importance (e.g., human health, preservation of buildings) significant efforts have been de...

Analysis of the ability of water resources to reduce the urban heat island in the Tokyo megalopolis.

PubMed

Nakayama, Tadanobu; Hashimoto, Shizuka

2011-01-01

Simulation procedure integrated with multi-scale in horizontally regional-urban-point levels and in vertically atmosphere-surface-unsaturated-saturated layers, was newly developed in order to predict the effect of urban geometry and anthropogenic exhaustion on the hydrothermal changes in the atmospheric/land and the interfacial areas of the Japanese megalopolis. The simulated results suggested that the latent heat flux in new water-holding pavement (consisting of porous asphalt and water-holding filler made of steel by-products based on silica compound) has a strong impact on hydrologic cycle and cooling temperature in comparison with the observed heat budget. We evaluated the relationship between the effect of groundwater use as a heat sink to tackle the heat island and the effect of infiltration on the water cycle in the urban area. The result indicates that effective management of water resources would be powerful for ameliorating the heat island and recovering sound hydrologic cycle there. Copyright © 2010 Elsevier Ltd. All rights reserved.

Anticoagulant rodenticides in urban bobcats: exposure, risk factors and potential effects based on a 16-year study

USGS Publications Warehouse

Serieys, Laurel E.K.; Armenta, Tiffany C.; Moriarty, Joanne G.; Boydston, Erin E.; Lyren, Lisa M.; Poppenga, Robert H.; Crooks, Kevin R.; Wayne, Robert K.; Riley, Seth P. D.

2015-01-01

Anticoagulant rodenticides (ARs) are increasingly recognized as a threat to nontarget wildlife. High exposure to ARs has been documented globally in nontarget predatory species and linked to the high prevalence of an ectoparasitic disease, notoedric mange. In southern California, mange associated with AR exposure has been the proximate cause of a bobcat (Lynx rufus) population decline. We measured AR exposure in bobcats from two areas in southern California, examining seasonal, demographic and spatial risk factors across landscapes including natural and urbanized areas. The long-term study included bobcats sampled over a 16-year period (1997–2012) and a wide geographic area. We sampled blood (N = 206) and liver (N = 172) to examine exposure ante- and post-mortem. We detected high exposure prevalence (89 %, liver; 39 %, blood) and for individuals with paired liver and blood data (N = 64), 92 % were exposed. Moreover, the animals with the most complete sampling were exposed most frequently to three or more compounds. Toxicant exposure was associated with commercial, residential, and agricultural development. Bobcats of both sexes and age classes were found to be at high risk of exposure, and we documented fetal transfer of multiple ARs. We found a strong association between certain levels of exposure (ppm), and between multiple AR exposure events, and notoedric mange. AR exposure was prevalent throughout both regions sampled and throughout the 16-year time period in the long-term study. ARs pose a substantial threat to bobcats, and likely other mammalian and avian predators, living at the urban-wildland interface.

Exposures to multiple air toxics in New York City.

PubMed Central

Kinney, Patrick L; Chillrud, Steven N; Ramstrom, Sonja; Ross, James; Spengler, John D

2002-01-01

Efforts to assess health risks associated with exposures to multiple urban air toxics have been hampered by the lack of exposure data for people living in urban areas. The TEACH (Toxic Exposure Assessment, a Columbia/Harvard) study was designed to characterize levels of and factors influencing personal exposures to urban air toxics among high school students living in inner-city neighborhoods of New York City and Los Angeles, California. This present article reports methods and data for the New York City phase of TEACH, focusing on the relationships between personal, indoor, and outdoor concentrations in winter and summer among a group of 46 high school students from the A. Philip Randolph Academy, a public high school located in the West Central Harlem section of New York City. Air pollutants monitored included a suite of 17 volatile organic compounds (VOCs) and aldehydes, particulate matter with a mass median aerodynamic diameter

Exposures to multiple air toxics in New York City.

PubMed

Kinney, Patrick L; Chillrud, Steven N; Ramstrom, Sonja; Ross, James; Spengler, John D

2002-08-01

Efforts to assess health risks associated with exposures to multiple urban air toxics have been hampered by the lack of exposure data for people living in urban areas. The TEACH (Toxic Exposure Assessment, a Columbia/Harvard) study was designed to characterize levels of and factors influencing personal exposures to urban air toxics among high school students living in inner-city neighborhoods of New York City and Los Angeles, California. This present article reports methods and data for the New York City phase of TEACH, focusing on the relationships between personal, indoor, and outdoor concentrations in winter and summer among a group of 46 high school students from the A. Philip Randolph Academy, a public high school located in the West Central Harlem section of New York City. Air pollutants monitored included a suite of 17 volatile organic compounds (VOCs) and aldehydes, particulate matter with a mass median aerodynamic diameter

Chlorpyrifos exposure in farmers and urban adults: Metabolic characteristic, exposure estimation, and potential effect of oxidative damage.

PubMed

Wang, Lei; Liu, Zhen; Zhang, Junjie; Wu, Yinghong; Sun, Hongwen

2016-08-01

Chlorpyrifos is a widely used organophosphorus pesticide that efficiently protects crops against pests. However, recent studies suggest that severe exposure to chlorpyrifos may present adverse health effects in human. To analyze the exposure level and metabolic characteristics of chlorpyrifos pesticide in urban adults and farmers with/without occupation pesticide contact, the occurrence of urinary chlorpyrifos and methyl chlorpyrifos (CP-me), as well as their metabolite, 3,5,6-trichloro-2-pyridinol (TCPy), was determined in farmers of an agricultural village in China, and in urban adults of a nearby town. The geometric mean (GM) concentrations of TCPy, which is the major marker of chlorpyrifos exposure, were 4.29 and 7.57μg/g-creatinine in urban adults and farmers before pesticide application, respectively. Chlorpyrifos spraying significantly increased the concentrations of urinary TCPy. In the first day after spraying, a GM concentration of 43.7μg/g-creatinine was detected in the urine specimens from farmers, which decreased to 38.1 and 22.8μg/g-creatinine in the second and third day after chlorpyrifos spraying. The ratio of TCPy and its parent compounds, i.e. chlorpyrifos and CP-me, was positively associated with the sum concentration of urinary chlorpyrifos, CP-me, and TCPy, suggesting the increasing metabolic efficiency of chlorpyrifos to TCPy at higher chlorpyrifos exposure levels. To estimate the farmers' occupational exposure to chlorpyrifos pesticide, a new model based on the fitted first-order elimination kinetics of TCPy was established. Occupational chlorpyrifos exposure in a farmer was estimated to be 3.70μg/kg-bw/day (GM), which is an exposure level that is higher than the recommended guideline levels. Significant increase of urinary 8-hydroxydeoxyguanosine (8-OHdG) was observed on the first day after chlorpyrifos spraying, which indicates a potential oxidative damage in farmers. However, urinary 8-OHdG returned to its baseline level within two days. Copyright © 2016 Elsevier Inc. All rights reserved.

Genotoxicity Biomarkers Associated with Exposure to Traffic And Near-Road Atmospheres: A Review

EPA Science Inventory

Genotoxicity Biomarkers Associated with Exposure to Traffic And Near-Road Atmospheres: A Review Diesel and gasoline emissions, which are the primary components of traffic exhaust, are known or possible human carcinogens, re...

A Numerical Simulation of Traffic-Related Air Pollution Exposures in Urban Street Canyons

NASA Astrophysics Data System (ADS)

Liu, J.; Fu, X.; Tao, S.

2016-12-01

Urban street canyons are usually associated with intensive vehicle emissions. However, the high buildings successively along both sides of a street block the dispersion of traffic-generated air pollutants, which enhances human exposure and adversely affects human health. In this study, an urban scale traffic pollution dispersion model is developed with the consideration of street distribution, canyon geometry, background meteorology, traffic assignment, traffic emissions and air pollutant dispersion. Vehicle exhausts generated from traffic flows will first disperse inside a street canyon along the micro-scale wind field (generated by computational fluid dynamics (CFD) model) and then leave the street canyon and further disperse over the urban area. On the basis of this model, the effects of canyon geometry on the distribution of NOx and CO from traffic emissions were studied over the center of Beijing, China. We found that an increase of building height along the streets leads to higher pollution levels inside streets and lower pollution levels outside, resulting in higher domain-averaged concentrations over the area. In addition, street canyons with equal (or highly uneven) building heights on two sides of a street tend to lower the urban-scale air pollution concentrations at pedestrian level. Our results indicate that canyon geometry strongly influences human exposure to traffic pollutants in the populated urban area. Carefully planning street layout and canyon geometry in consideration of traffic demand as well as local weather pattern may significantly reduce the chances of unhealthy air being inhaled by urban residents.

Populations potentially exposed to traffic-related air pollution in seven world cities.

PubMed

Su, Jason G; Apte, Joshua S; Lipsitt, Jonah; Garcia-Gonzales, Diane A; Beckerman, Bernardo S; de Nazelle, Audrey; Texcalac-Sangrador, José Luis; Jerrett, Michael

2015-05-01

Traffic-related air pollution (TRAP) likely exerts a large burden of disease globally, and in many places, traffic is increasing dramatically. The impact, however, of urban form on the portion of population potentially exposed to TRAP remains poorly understood. In this study, we estimate portions of population potentially exposed to TRAP across seven global cities of various urban forms. Data on population distributions and road networks were collected from the best available sources in each city and from remote sensing analysis. Using spatial mapping techniques, we first overlaid road buffers onto population data to estimate the portions of population potentially exposed for four plausible impact zones. Based on a most likely scenario with impacts from highways up to 300meters and major roadways up to 50meters, we identified that the portions of population potentially exposed for the seven cities ranged from 23 to 96%. High-income North American cities had the lowest potential exposure portions, while those in Europe had the highest. Second, we adjusted exposure zone concentration levels based on a literature suggested multiplier for each city using corresponding background concentrations. Though Beijing and Mexico City did not have the highest portion of population exposure, those in their exposure zones had the highest levels of exposure. For all seven cities, the portion of population potentially exposed was positively correlated with roadway density and, to a lesser extent, with population density. These analyses suggest that urban form may influence the portion of population exposed to TRAP and vehicle emissions and other factors may influence the exposure levels. Greater understanding of urban form and other factors influencing potential exposure to TRAP may help inform interventions that protect public health. Copyright © 2014 Elsevier Ltd. All rights reserved.

Enhanced functional connectivity properties of human brains during in-situ nature experience

PubMed Central

2016-01-01

In this study, we investigated the impacts of in-situ nature and urban exposure on human brain activities and their dynamics. We randomly assigned 32 healthy right-handed college students (mean age = 20.6 years, SD = 1.6; 16 males) to a 20 min in-situ sitting exposure in either a nature (n = 16) or urban environment (n = 16) and measured their Electroencephalography (EEG) signals. Analyses revealed that a brief in-situ restorative nature experience may induce more efficient and stronger brain connectivity with enhanced small-world properties compared with a stressful urban experience. The enhanced small-world properties were found to be correlated with “coherent” experience measured by Perceived Restorativeness Scale (PRS). Exposure to nature also induces stronger long-term correlated activity across different brain regions with a right lateralization. These findings may advance our understanding of the functional activities during in-situ environmental exposures and imply that a nature or nature-like environment may potentially benefit cognitive processes and mental well-being. PMID:27547533

Exposure to violence among urban school-aged children: is it only on television?

PubMed

Purugganan, O H; Stein, R E; Silver, E J; Benenson, B S

2000-10-01

To measure exposure to different types of violence among school-aged children in a primary care setting. Child interviews using an instrument measuring 4 types of exposure (direct victimization, witnessing, hearing reports, media). Violent acts measured include being beaten up, chased/threatened, robbed/mugged, stabbed/shot, killed. Pediatric primary care clinic of large urban hospital. Convenience sample of 175 children 9-12 years old and their mothers. A total of 53% of the children were boys, 55% were Hispanic, and 40% received public assistance. All children had been exposed to media violence. A total of 97% (170/175) had been exposed to more direct forms of violence; 77% had witnessed violence involving strangers; 49% had witnessed violence involving familiar persons; 49% had been direct victims; and 31% had witnessed someone being shot, stabbed, or killed. Exposure to violence was significantly associated with being male. Most school-aged children who visited a pediatric primary care clinic of a large urban hospital had directly experienced violence as witnesses and/or victims.

Study of the air quality in the surroundings of an urban park: A micrometeorological approach

NASA Astrophysics Data System (ADS)

Sastre, Mariano; Yagüe, Carlos; Arrillaga, Jon A.; Román-Cascón, Carlos; Maqueda, Gregorio; Artíñano, Begoña; Díaz-Ramiro, Elías; Gómez-Moreno, Francisco J.; Barreiro, Marcos; Borge, Rafael; Narros, Adolfo; Pérez, Javier; Quaassdorff, Christina

2017-04-01

In this work we study the differences showed by two types of pollutants, particulate matter (PM) and NOx, by comparing ambient concentration measurements within an urban park versus the corresponding values nearby (but outside) it. The results are linked to both proximity to emission sources, such as road traffic, and the microscale atmospheric conditions. The work is motivated by the fact that poor air quality is a crucial issue of current cities. For some of them it is not uncommon to face this problem with occasional traffic restrictions when high concentrations of pollutants are reached. These events occur more frequently with specific large-scale atmospheric conditions, for example when a strong anticyclone is present. As the meteorological conditions may significantly influence the pollutants concentrations, the research project TECNAIRE-CM (Innovative technologies for the assessment and improvement of urban air quality) aims to provide new approaches to obtain proper descriptions of the urban pollution and its dynamics at different spatial and temporal scales, not only the synoptic scale. So far, a few field campaigns have been developed within TECNAIRE-CM at two locations in the city of Madrid, which are considered hot spots according to the air quality network records. Here we use the data from a field campaign carried out during summer 2016, which consider standard pollution and meteorological measurements, as well as sonic anemometer data. The latter help to include atmospheric turbulence as a significant agent for air quality characterization. The instrumentation was deployed at a location with considerable traffic density, but nearby a border of the main urban park of the city, so that its influence might be investigated. Supplementary data considered for this work correspond to permanent instrumentation within the park. With this extra information we can compare both measurements inside and outside the park. Therefore, we study the effect on wind, turbulence or air quality when we measure at a site either directly exposed to traffic emissions or partly protected and with a reduced influence of typical atmospheric urban phenomena. This work has been funded by Madrid Regional Research Plan through TECNAIRE (P2013/MAE-2972).

Radiocarbon Records of Fossil Fuel Emissions From Urban Trees in the Greater Salt Lake Valley From Mid-Century to Present.

NASA Astrophysics Data System (ADS)

Chritz, K.; Buchert, M.; Walker, J. C.; Mendoza, D.; Pataki, D. E.; Xu, X.; Lin, J. C.

2017-12-01

Generating long term records of fossil fuel emissions of urban environments is complicated by the fact that direct observations of emissions and urban atmospheric CO2 concentrations were only collected in the recent past. Radiocarbon (14C) in tree rings from urban trees can provide archives of fossil fuel emissions that may track population growth over time, as higher population density is typically correlated with increased vehicular traffic and associated CO2 emissions, which are radiocarbon dead. We present radiocarbon measurements (n=125) from five roadside green ash trees (Fraxinus pennsylvanica) located in three cities of northern Utah - Salt Lake City (urban, 2016 population: 193,744), Logan City (agricultural, 2016 population: 49,110) and Heber (rural, 2016 population: 14,969). Urban trees were cored in four cardinal directions and ring widths were measured and counted to establish a chronology. One ring from every third year in a single core from each tree was removed and holocellulose was extracted from bulk wood of individual rings for 14C analysis. Fraction CO2 from fossil fuel burning (CO2-ff) was calculated using a simple mass-balance calculation from measured 14C values and remote background atmospheric 14CO2 values for NH Zone 2. The data from all three cities indicate a general trend of increasing CO2-ff uptake by the trees from 1980s to present, as expected with increased population growth and vehicular traffic. However, records in all three cities show unique elevated CO2-ff prior to the 1980s, assuming similar climate patterns through time, diverging from historic population size. We employed atmospheric simulations from the STILT (Stochastic Time-Inverted Lagrangian Transport) models for each of these trees to create footprints to determine source areas for CO2. These footprints reveal that atmospheric sampling areas can be large for certain trees, and other sources of 14C dead carbon, such as coal and natural gas from industrial emissions, should also be considered when building these records.

Intake-to-delivered-energy ratios for central station and distributed electricity generation in California

NASA Astrophysics Data System (ADS)

Heath, Garvin A.; Nazaroff, William W.

In previous work, we showed that the intake fraction (iF) for nonreactive primary air pollutants was 20 times higher in central tendency for small-scale, urban-sited distributed electricity generation (DG) sources than for large-scale, central station (CS) power plants in California [Heath, G.A., Granvold, P.W., Hoats, A.S., Nazaroff, W.W., 2006. Intake fraction assessment of the air pollutant exposure implications of a shift toward distributed electricity generation. Atmospheric Environment 40, 7164-7177]. The present paper builds on that study, exploring pollutant- and technology-specific aspects of population inhalation exposure from electricity generation. We compare California's existing CS-based system to one that is more reliant on DG units sited in urban areas. We use Gaussian plume modeling and a GIS-based exposure analysis to assess 25 existing CSs and 11 DG sources hypothetically located in the downtowns of California's most populous cities. We consider population intake of three pollutants—PM 2.5, NO x and formaldehyde—directly emitted by five DG technologies—natural gas (NG)-fired turbines, NG internal combustion engines (ICE), NG microturbines, diesel ICEs, and fuel cells with on-site NG reformers. We also consider intake of these pollutants from existing CS facilities, most of which use large NG turbines, as well as from hypothetical facilities located at these same sites but meeting California's best-available control technology standards. After systematically exploring the sensitivity of iF to pollutant decay rate, the iFs for each of the three pollutants for all DG and CS cases are estimated. To efficiently compare the pollutant- and technology-specific exposure potential on an appropriate common basis, a new metric is introduced and evaluated: the intake-to-delivered-energy ratio (IDER). The IDER expresses the mass of pollutant inhaled by an exposed population owing to emissions from an electricity generation unit per quantity of electric energy delivered to the place of use. We find that the central tendency of IDER is much greater for almost every DG technology evaluated than for existing CS facilities in California.

Benzene patterns in different urban environments and a prediction model for benzene rates based on NOx values

NASA Astrophysics Data System (ADS)

Paz, Shlomit; Goldstein, Pavel; Kordova-Biezuner, Levana; Adler, Lea

2017-04-01

Exposure to benzene has been associated with multiple severe impacts on health. This notwithstanding, at most monitoring stations, benzene is not monitored on a regular basis. The aims of the study were to compare benzene rates in different urban environments (region with heavy traffic and industrial region), to analyse the relationship between benzene and meteorological parameters in a Mediterranean climate type, to estimate the linkages between benzene and NOx and to suggest a prediction model for benzene rates based on NOx levels in order contribute to a better estimation of benzene. Data were used from two different monitoring stations, located on the eastern Mediterranean coast: 1) a traffic monitoring station in Tel Aviv, Israel (TLV) located in an urban region with heavy traffic; 2) a general air quality monitoring station in Haifa Bay (HIB), located in Israel's main industrial region. At each station, hourly, daily, monthly, seasonal, and annual data of benzene, NOx, mean temperature, relative humidity, inversion level, and temperature gradient were analysed over three years: 2008, 2009, and 2010. A prediction model for benzene rates based on NOx levels (which are monitored regularly) was developed to contribute to a better estimation of benzene. The severity of benzene pollution was found to be considerably higher at the traffic monitoring station (TLV) than at the general air quality station (HIB), despite the location of the latter in an industrial area. Hourly, daily, monthly, seasonal, and annual patterns have been shown to coincide with anthropogenic activities (traffic), the day of the week, and atmospheric conditions. A strong correlation between NOx and benzene allowed the development of a prediction model for benzene rates, based on NOx, the day of the week, and the month. The model succeeded in predicting the benzene values throughout the year (except for September). The severity of benzene pollution was found to be considerably higher at the traffic station (TLV) than at the general air quality station (HIB), despite being located in an industrial area. Hourly, daily, seasonal, and annual patterns of benzene rates have been shown to coincide with anthropogenic activities (traffic), day of the week, and atmospheric conditions. A prediction model for benzene rates was developed, based on NOx, the day of the week, and the month. The model suggested in this study might be useful for identifying potential risk of benzene in other urban environments.

Climate-Related Hazards: A Method for Global Assessment of Urban and Rural Population Exposure to Cyclones, Droughts, and Floods

PubMed Central

Christenson, Elizabeth; Elliott, Mark; Banerjee, Ovik; Hamrick, Laura; Bartram, Jamie

2014-01-01

Global climate change (GCC) has led to increased focus on the occurrence of, and preparation for, climate-related extremes and hazards. Population exposure, the relative likelihood that a person in a given location was exposed to a given hazard event(s) in a given period of time, was the outcome for this analysis. Our objectives were to develop a method for estimating the population exposure at the country level to the climate-related hazards cyclone, drought, and flood; develop a method that readily allows the addition of better datasets to an automated model; differentiate population exposure of urban and rural populations; and calculate and present the results of exposure scores and ranking of countries based on the country-wide, urban, and rural population exposures to cyclone, drought, and flood. Gridded global datasets on cyclone, drought and flood occurrence as well as population density were combined and analysis was carried out using ArcGIS. Results presented include global maps of ranked country-level population exposure to cyclone, drought, flood and multiple hazards. Analyses by geography and human development index (HDI) are also included. The results and analyses of this exposure assessment have implications for country-level adaptation. It can also be used to help prioritize aid decisions and allocation of adaptation resources between countries and within a country. This model is designed to allow flexibility in applying cyclone, drought and flood exposure to a range of outcomes and adaptation measures. PMID:24566046

Assessing atmospheric particulate matter distribution based on Saturation Isothermal Remanent Magnetization of herbaceous and tree leaves in a tropical urban environment.

PubMed

Barima, Yao Sadaiou Sabas; Angaman, Djédoux Maxime; N'gouran, Kobenan Pierre; Koffi, N'guessan Achille; Kardel, Fatemeh; De Cannière, Charles; Samson, Roeland

2014-02-01

Particulate matter (PM) emissions, and the associated human health risks, are likely to continue increasing in urban environments of developing countries like Abidjan (Ivory Cost). This study evaluated the potential of leaves of several herbaceous and tree species as bioindicators of urban particulate matter pollution, and its variation over different land use classes, in a tropical area. Four species well distributed (presence frequencies >90%) over all land use classes, easy to harvest and whose leaves are wide enough to be easily scanned were selected, i.e.: Amaranthus spinosus (Amaranthaceae), Eleusine indica (Poaceae), Panicum maximum (Poaceae) and Ficus benjamina (Moraceae). Leaf sampling of these species was carried out at 3 distances from the road and at 3 height levels. Traffic density was also noted and finally biomagnetic parameters of these leaves were determined. Results showed that Saturation Isothermal Remanent Magnetization (SIRM) of leaves was at least 4 times higher (27.5×10(-6)A) in the vicinity of main roads and industrial areas than in parks and residential areas. The main potential sources of PM pollution were motor vehicles and industries. The slightly hairy leaves of the herbaceous plant A. spinosus and the waxy leaves of the tree F. benjamina showed the highest SIRM (25×10(-6)A). Leaf SIRM increased with distance to road (R(2)>0.40) and declined with sampling height (R(2)=0.17). The distance between 0 and 5m from the road seemed to be the most vulnerable in terms of PM pollution. This study has showed that leaf SIRM of herbaceous and tree species can be used to assess PM exposure in tropical urban environments. © 2013.

A perspective on the potential development of environmentally acceptable light-duty diesel vehicles.

PubMed Central

Hammerle, R; Schuetzle, D; Adams, W

1994-01-01

Between 1979 and 1985, an international technical focus was placed upon potential human health effects associated with exposure to diesel emissions. A substantial data base was developed on the composition of diesel emissions; the fate of these emissions in the atmosphere; and the effects of whole particles and their chemical constituents on microorganisms, cells, and animals. Since that time, a number of significant developments have been made in diesel engine technology that require a new look at the future acceptability of introducing significant numbers of light-duty diesel automobiles into the European and American markets. Significant engineering improvements have been made in engine design, catalysts, and traps. As a result, particle emissions and particle associated organic emissions have been reduced by about 10 and 30 times, respectively, during the past 10 years. Research studies to help assess the environmental acceptability of these fuel-efficient engines include the development of an emissions data base for current and advanced diesel engines, the effect of diesel emissions on urban ozone formation and atmospheric particle concentrations, the effect of fuel composition, e.g., lower sulfur and additives on emissions, animal inhalation toxicology studies, and fundamental molecular biology studies. PMID:7529704

The Dallas-Fort Worth (DFW) Urban Radar Network: Enhancing Resilience in the Presence of Floods, Tornadoes, Hail and High Winds

NASA Astrophysics Data System (ADS)

Chandra*, Chandrasekar V.; the full DFW Team

2015-04-01

Currently, the National Weather Service (NWS) Next Generation Weather Radar (NEXRAD) provides observations updated every five-six minutes across the United States. However, at the maximum NEXRAD operating range of 230 km, the 0.5 degree radar beam (lowest tilt) height is about 5.4 km above ground level (AGL) because of the effect of Earth curvature. Consequently, much of the lower atmosphere (1-3 km AGL) cannot be observed by the NEXRAD. To overcome the fundamental coverage limitations of today's weather surveillance radars, and improve the spatial and temporal resolution issues, at urban scale, the National Science Foundation Engineering Research Center (NSF-ERC) for Collaborative Adaptive Sensing of the Atmosphere (CASA) has embarked the development of Dallas-Fort worth (DFW) urban remote sensing network to conduct high-resolution sensing in the lower atmosphere for a metropolitan environment, communicate high resolution observations and nowcasting of severe weather including flash floods, hail storms and high wind events. Being one of the largest inland metropolitan areas in the U.S., the DFW Metroplex is home to over 6.5 million people by 2012 according to the North Central Texas Council of Governments (NCTCOG). It experiences a wide range of natural weather hazards, including urban flash flood, high wind, tornado, and hail, etc. Successful monitoring of the rapid changing meteorological conditions in such a region is necessary for emergency management and decision making. Therefore, it is an ideal location to investigate the impacts of hazardous weather phenomena, to enhance resilience in an urban setting and demonstrate the CASA concept in a densely populated urban environment. The DFW radar network consists of 8 dual-polarization X-band weather radars and standard NEXRAD S-band radar, covering the greater DFW metropolitan region. This paper will present high resolution observation of tornado, urban flood, hail storm and damaging wind event all within the city.

Impacts of atmospheric nitrogen deposition on vegetation and soils in Joshua Tree National Park

Treesearch

E.B. Allen; L. Rao; R.J. Steers; A. Bytnerowicz; M.E. Fenn

2009-01-01

The western Mojave Desert is downwind of nitrogen emissions from coastal and inland urban sources, especially automobiles. The objectives of this research were to measure reactive nitrogen (N) in the atmosphere and soils along a N-deposition gradient at Joshua Tree National Park and to examine its effects on invasive and native plant species. Atmospheric nitric acid (...

Environmental and biological monitoring of benzene in traffic policemen, police drivers and rural outdoor male workers.

PubMed

Manuela, Ciarrocca; Francesco, Tomei; Tiziana, Caciari; Assunta, Capozzella; Lara, Scimitto; Nadia, Nardone; Giorgia, Andreozzi; Barbara, Scala; Maria, Fiaschetti; Carlotta, Cetica; Valeria, Di Giorgio; Pia, Schifano Maria; Gianfranco, Tomei; Angela, Sancini

2012-05-01

To evaluate exposure to benzene in urban and rural areas, an investigation into personal exposure to benzene in traffic policemen, police drivers and rural (roadmen) male outdoor workers was carried out. Personal samples and data acquired using fixed monitoring stations located in different areas of the city were used to measure personal exposure to benzene in 62 non-smoker traffic policemen, 22 police drivers and 57 roadmen. Blood benzene, urinary trans-trans muconic acid (t,t-MA) and S-phenyl-mercapturic acid (S-PMA) were measured at the end of work shift in 62 non-smoker traffic policemen, 22 police drivers and 57 roadmen and 34 smoker traffic policemen, 21 police drivers and 53 roadmen. Exposure to benzene was similar among non-smoker traffic policemen and police drivers and higher among non-smoker urban workers compared to rural workers. Blood benzene, t,t-MA and S-PMA were similar among non-smoker traffic policemen and police drivers; blood benzene and t,t-MA were significantly higher in non-smoker urban workers compared to rural workers. Significant increases in t,t-MA were found in smokers vs. non-smokers. In non-smoker urban workers airborne benzene and blood benzene, and t,t-MA and S-PMA were significantly correlated. This study gives an evaluation of the exposure to benzene in an urban area, comparing people working in the street or in cars, to people working in a rural area. Benzene is a certain carcinogen for humans. The results we showed should lead to more in-depth studies about the effects on health of these categories of workers.

Urinary bisphenol A concentrations in girls from rural and urban Egypt: a pilot study

PubMed Central

2012-01-01

Background Exposure to endocrine active compounds, including bisphenol A (BPA), remains poorly characterized in developing countries despite the fact that behavioral practices related to westernization have the potential to influence exposure. BPA is a high production volume chemical that has been associated with metabolic dysfunction as well as behavioral and developmental effects in people, including children. In this pilot study, we evaluate BPA exposure and assess likely pathways of exposure among girls from urban and rural Egypt. Methods We measured urinary concentrations of total (free plus conjugated) species of BPA in spot samples in urban (N = 30) and rural (N = 30) Egyptian girls, and compared these concentrations to preexisting data from age-matched American girls (N = 47) from the U.S. National Health and Nutrition Examination Survey (NHANES). We also collected anthropometric and questionnaire data regarding food storage behaviors to assess potential routes of exposure. Results Urban and rural Egyptian girls exhibited similar concentrations of urinary total BPA, with median unadjusted values of 1.00 and 0.60 ng/mL, respectively. Concentrations of urinary BPA in this group of Egyptian girls (median unadjusted: 0.70 ng/mL) were significantly lower compared to age-matched American girls (median unadjusted: 2.60 ng/mL) according to NHANES 2009-2010 data. Reported storage of food in plastic containers was a significant predictor of increasing concentrations of urinary BPA. Conclusions Despite the relatively low urinary BPA concentrations within this Egyptian cohort, the significant association between food storage behaviors and increasing urinary BPA concentration highlights the need to understand food and consumer product patterns that may be closing the gap between urban and rural lifestyles. PMID:22472083

Effects of climatic changes and urban air pollution on the rising trends of respiratory allergy and asthma

PubMed Central

2011-01-01

Over the past two decades there has been increasing interest in studies regarding effects on human health of climate changes and urban air pollution. Climate change induced by anthropogenic warming of the earth's atmosphere is a daunting problem and there are several observations about the role of urbanization, with its high levels of vehicle emissions and other pollutants, and westernized lifestyle with respect to the rising frequency of respiratory allergic diseases observed in most industrialized countries. There is also evidence that asthmatic subjects are at increased risk of developing exacerbations of bronchial obstruction with exposure to gaseous (ozone, nitrogen dioxide, sulfur dioxide) and particulate inhalable components of air pollution. A change in the genetic predisposition is an unlikely cause of the increasing frequency in allergic diseases because genetic changes in a population require several generations. Consequently, environmental factors such as climate change and indoor and outdoor air pollution may contribute to explain the increasing frequency of respiratory allergy and asthma. Since concentrations of airborne allergens and air pollutants are frequently increased contemporaneously, an enhanced IgE-mediated response to aeroallergens and enhanced airway inflammation could account for the increasing frequency of allergic respiratory diseases and bronchial asthma. Scientific societies such as the European Academy of Allergy and Clinical Immunology, European Respiratory Society and the World Allergy Organization have set up committees and task forces to produce documents to focalize attention on this topic, calling for prevention measures. PMID:22958620

Effects of climatic changes and urban air pollution on the rising trends of respiratory allergy and asthma.

PubMed

D'Amato, Gennaro

2011-02-28

Over the past two decades there has been increasing interest in studies regarding effects on human health of climate changes and urban air pollution. Climate change induced by anthropogenic warming of the earth's atmosphere is a daunting problem and there are several observations about the role of urbanization, with its high levels of vehicle emissions and other pollutants, and westernized lifestyle with respect to the rising frequency of respiratory allergic diseases observed in most industrialized countries.There is also evidence that asthmatic subjects are at increased risk of developing exacerbations of bronchial obstruction with exposure to gaseous (ozone, nitrogen dioxide, sulfur dioxide) and particulate inhalable components of air pollution.A change in the genetic predisposition is an unlikely cause of the increasing frequency in allergic diseases because genetic changes in a population require several generations. Consequently, environmental factors such as climate change and indoor and outdoor air pollution may contribute to explain the increasing frequency of respiratory allergy and asthma. Since concentrations of airborne allergens and air pollutants are frequently increased contemporaneously, an enhanced IgE-mediated response to aeroallergens and enhanced airway inflammation could account for the increasing frequency of allergic respiratory diseases and bronchial asthma.Scientific societies such as the European Academy of Allergy and Clinical Immunology, European Respiratory Society and the World Allergy Organization have set up committees and task forces to produce documents to focalize attention on this topic, calling for prevention measures.

Experimental studies and physically substantiated model of carbon dioxide emission from the exposed cultural layer of Velikii Novgorod

NASA Astrophysics Data System (ADS)

Smagin, A. V.; Dolgikh, A. V.; Karelin, D. V.

2016-04-01

The results of quantitative assessment and modeling of carbon dioxide emission from urban pedolithosediments (cultural layer) in the central part of Velikii Novgorod are discussed. At the first stages after the exposure of the cultural layer to the surface in archaeological excavations, very high CO2 emission values reaching 10-15 g C/(m2 h) have been determined. These values exceed the normal equilibrium emission from the soil surface by two orders of magnitude. However, they should not be interpreted as indications of the high biological activity of the buried urban sediments. A model based on physical processes shows that the measured emission values can be reliably explained by degassing of the soil water and desorption of gases from the urban sediments. This model suggests the diffusion mechanism of the transfer of carbon dioxide from the cultural layer into the atmosphere; in addition, it includes the equations to describe nonequilibrium interphase interactions (sorption-desorption and dissolution-degassing of CO2) with the first-order kinetics. With the use of statistically reliable data on physical parameters—the effective diffusion coefficient as dependent on the aeration porosity, the effective solubility, the Henry constant for the CO2 sorption, and the kinetic constants of the CO2 desorption and degassing of the soil solution—this model reproduces the experimental data on the dynamics of CO2 emission from the surface of the exposed cultural layer obtained by the static chamber method.

Urban heat fluxes in the subsurface of Cologne, Germany

NASA Astrophysics Data System (ADS)

Zhu, K.; Bayer, P.; Blum, P.

2012-04-01

Urbanization during the last hundred years has led to both environmental and thermal impacts on the subsurface. The urban heat island (UHI) effect is mostly described as an atmospheric phenomenon, where the measured aboveground temperatures in cities are elevated in comparison to undisturbed rural regions. However, UHIs can be found below, as well as above ground. A large amount of anthropogenic heat migrates into the urban subsurface, which also raises the ground temperature and permanently changes the thermal conditions in shallow aquifers. The main objective of our work is to study and determine the urban heat fluxes in Cologne, Germany, and to improve our understanding of the dynamics of subsurface energy fluxes in UHIs. Ideally, our findings will contribute to strategic and more sustainable geothermal use in cities. For a quantitative analysis of the energy fluxes within the subsurface and across the atmospheric boundary, two and three-dimensional coupled numerical flow and heat transport models were developed. The simulation results indicate that during the past hundred years, an average vertical urban heat flux that ranges between 80 and 375 mW m-2 can be deduced. Thermal anomalies have migrated into the local urban aquifer system and they reach a depth of about 150 m. In this context, the influence of the regional groundwater flow on the subsurface heat transport and temperature development is comprehensively discussed.

The urban boundary-layer field campaign in marseille (ubl/clu-escompte): set-up and first results

NASA Astrophysics Data System (ADS)

Mestayer, P.G.; Durand, P.; Augustin, P.; Bastin, S.; Bonnefond, J.-M.; Benech, B.; Campistron, B.; Coppalle, A.; Delbarre, H.; Dousset, B.; Drobinski, P.; Druilhet, A.; Frejafon, E.; Grimmond, C.S.B.; Groleau, D.; Irvine, M.; Kergomard, C.; Kermadi, S.; Lagouarde, J.-P.; Lemonsu, A.; Lohou, F.; Long, N.; Masson, V.; Moppert, C.; Noilhan, J.; Offerle, B.; Oke, T.R.; Pigeon, G.; Puygrenier, V.; Roberts, S.; Rosant, J.-M.; Sanid, F.; Salmond, J.; Talbaut, M.; Voogt, J.

The UBL/CLU (urban boundary layer/couche limite urbaine) observation and modelling campaign is a side-project of the regional photochemistry campaign ESCOMPTE. UBL/CLU focuses on the dynamics and thermodynamics of the urban boundary layer of Marseille, on the Mediterranean coast of France. The objective of UBL/CLU is to document the four-dimensional structure of the urban boundary layer and its relation to the heat and moisture exchanges between the urban canopy and the atmosphere during periods of low wind conditions, from June 4 to July 16, 2001. The project took advantage of the comprehensive observational set-up of the ESCOMPTE campaign over the Berre-Marseille area, especially the ground-based remote sensing, airborne measurements, and the intensive documentation of the regional meteorology. Additional instrumentation was installed as part of UBL/CLU. Analysis objectives focus on (i) validation of several energy balance computational schemes such as LUMPS, TEB and SM2-U, (ii) ground truth and urban canopy signatures suitable for the estimation of urban albedos and aerodynamic surface temperatures from satellite data, (iii) high resolution mapping of urban land cover, land-use and aerodynamic parameters used in UBL models, and (iv) testing the ability of high resolution atmospheric models to simulate the structure of the UBL during land and sea breezes, and the related transport and diffusion of pollutants over different districts of the city. This paper presents initial results from such analyses and details of the overall experimental set-up.

Winter climate change effects on soil C and N cycles in urban grasslands.

PubMed

Durán, Jorge; Rodríguez, Alexandra; Morse, Jennifer L; Groffman, Peter M

2013-09-01

Despite growing recognition of the role that cities have in global biogeochemical cycles, urban systems are among the least understood of all ecosystems. Urban grasslands are expanding rapidly along with urbanization, which is expected to increase at unprecedented rates in upcoming decades. The large and increasing area of urban grasslands and their impact on water and air quality justify the need for a better understanding of their biogeochemical cycles. There is also great uncertainty about the effect that climate change, especially changes in winter snow cover, will have on nutrient cycles in urban grasslands. We aimed to evaluate how reduced snow accumulation directly affects winter soil frost dynamics, and indirectly greenhouse gas fluxes and the processing of carbon (C) and nitrogen (N) during the subsequent growing season in northern urban grasslands. Both artificial and natural snow reduction increased winter soil frost, affecting winter microbial C and N processing, accelerating C and N cycles and increasing soil : atmosphere greenhouse gas exchange during the subsequent growing season. With lower snow accumulations that are predicted with climate change, we found decreases in N retention in these ecosystems, and increases in N2 O and CO2 flux to the atmosphere, significantly increasing the global warming potential of urban grasslands. Our results suggest that the environmental impacts of these rapidly expanding ecosystems are likely to increase as climate change brings milder winters and more extensive soil frost. © 2013 John Wiley & Sons Ltd.

Building-Resolved CFD Simulations for Greenhouse Gas Transport and Dispersion over Washington DC / Baltimore

NASA Astrophysics Data System (ADS)

Prasad, K.; Lopez-Coto, I.; Ghosh, S.; Mueller, K.; Whetstone, J. R.

2015-12-01

The North-East Corridor project aims to use a top-down inversion methodology to quantify sources of Greenhouse Gas (GHG) emissions over urban domains such as Washington DC / Baltimore with high spatial and temporal resolution. Atmospheric transport of tracer gases from an emission source to a tower mounted receptor are usually conducted using the Weather Research and Forecasting (WRF) model. For such simulations, WRF employs a parameterized turbulence model and does not resolve the fine scale dynamics generated by the flow around buildings and communities comprising a large city. The NIST Fire Dynamics Simulator (FDS) is a computational fluid dynamics model that utilizes large eddy simulation methods to model flow around buildings at length scales much smaller than is practical with WRF. FDS has the potential to evaluate the impact of complex urban topography on near-field dispersion and mixing difficult to simulate with a mesoscale atmospheric model. Such capabilities may be important in determining urban GHG emissions using atmospheric measurements. A methodology has been developed to run FDS as a sub-grid scale model within a WRF simulation. The coupling is based on nudging the FDS flow field towards that computed by WRF, and is currently limited to one way coupling performed in an off-line mode. Using the coupled WRF / FDS model, NIST will investigate the effects of the urban canopy at horizontal resolutions of 10-20 m in a domain of 12 x 12 km. The coupled WRF-FDS simulations will be used to calculate the dispersion of tracer gases in the North-East Corridor and to evaluate the upwind areas that contribute to tower observations, referred to in the inversion community as influence functions. Results of this study will provide guidance regarding the importance of explicit simulations of urban atmospheric turbulence in obtaining accurate estimates of greenhouse gas emissions and transport.

Understanding the Impacts of Land Uses on the Source Apportionment of Atmospheric Contamination By Polycyclic Aromatic Hydrocarbons throughout a Small State in the Northeast United States

NASA Astrophysics Data System (ADS)

Schifman, L. A.; Boving, T. B.

2014-12-01

Polycyclic aromatic hydrocarbons (PAH) are ubiquitous contaminants that enter the environment through combustion processes and are often found in higher concentration of urban areas. However, once released, these compounds can travel long distances via transport through the atmosphere and can be deposited on the landscape far away from their original source. This PAH deposition pattern can slowly lead to the diffuse contamination of whole landscapes. Since most of the air masses entering the northeastern United States originate from the Midwest where coal burning power plants are plentiful, several atmospheric pollutants are introduced to the region in addition to local sources. Here, atmospheric deposition of PAHs in six different locations throughout Rhode Island was measured using passive bulk-deposition samplers for 3 years. The data were analyzed statistically by principal component analysis and factor analysis to identify the source of contamination and respective apportionment. The data clearly show that an urban-to- rural gradient exists where deposition rates are significantly higher in urban areas (up to 12325 ng/d m2 ∑PAH) compared to rural areas (as low as 11 ng/d m2 ∑PAH) and also follow seasonal trends that show higher deposition rates in the fall and winter compared to the summer and spring time. Further, based on PAH source apportionment ratios, contamination origins differ spatially. For example, fossil fuel, coal, and vehicle combustion is present in all samples; however fossil fuel combustion is dominant in urban samples. In Rural areas biomass combustion is much more prevalent and is not as greatly represented in urban or suburban areas. Therefore, even in a small state such as Rhode Island airborne PAH contamination can be fingerprinted readily for different sampling areas, indicating that distant emission sources have a widespread impact on regional air quality.

Overview of the 2006 MILAGRO Campaign in Mexico City: Transport and Transformation of Emissions from a Megacity

NASA Astrophysics Data System (ADS)

Molina, L.; MILAGRO Science Team

2009-04-01

Megacities (metropolitan areas with population over 10 million) and large urban centers present a major challenge for the global environment. Population growth, increasing motorization and industrialization have resulted in a higher demand for energy, greater use of fossil fuels, and more emission of pollutants into the atmosphere. As a result, air pollution has become not only one of the central environmental problems of the century, but also presents serious consequences to human health and ecosystems and economic costs to society. MILAGRO (Megacity Initiative: Local and Global Research Observations) is the first international effort to study the impact of air pollutants generated and exported by megacity. The Mexico City Metropolitan Area (MCMA) - one of the largest megacities in the world - was selected as the initial case study for MILAGRO. The measurement phase consisted of a month-long series of carefully coordinated observations of the chemistry and physics of the atmosphere in and near Mexico City during March 2006, using a wide range of instruments at ground sites, on aircraft and satellites, complemented by meteorological forecasting and numerical simulations. Together, these research observations have provided the most comprehensive characterization of Mexico City's urban and regional air pollution that will take years to analyze and evaluate fully. Initial analysis of the data is focused on understanding meteorology, emissions, urban and regional photochemistry, aerosol evolution and radiative effects - spanning the urban to regional scale transition. Many interesting aspects of atmospheric chemistry in and near the MCMA are emerging and have already added significantly to our understanding of the chemical and physical properties of the city's reactive atmosphere and the regional impacts. The information can be useful for decision-makers in Mexico in developing air quality management strategies as well as provide insights to air pollution problems in other megacities and large urban centers around the world.

Urban community gardeners' knowledge and perceptions of soil contaminant risks.

PubMed

Kim, Brent F; Poulsen, Melissa N; Margulies, Jared D; Dix, Katie L; Palmer, Anne M; Nachman, Keeve E

2014-01-01

Although urban community gardening can offer health, social, environmental, and economic benefits, these benefits must be weighed against the potential health risks stemming from exposure to contaminants such as heavy metals and organic chemicals that may be present in urban soils. Individuals who garden at or eat food grown in contaminated urban garden sites may be at risk of exposure to such contaminants. Gardeners may be unaware of these risks and how to manage them. We used a mixed quantitative/qualitative research approach to characterize urban community gardeners' knowledge and perceptions of risks related to soil contaminant exposure. We conducted surveys with 70 gardeners from 15 community gardens in Baltimore, Maryland, and semi-structured interviews with 18 key informants knowledgeable about community gardening and soil contamination in Baltimore. We identified a range of factors, challenges, and needs related to Baltimore community gardeners' perceptions of risk related to soil contamination, including low levels of concern and inconsistent levels of knowledge about heavy metal and organic chemical contaminants, barriers to investigating a garden site's history and conducting soil tests, limited knowledge of best practices for reducing exposure, and a need for clear and concise information on how best to prevent and manage soil contamination. Key informants discussed various strategies for developing and disseminating educational materials to gardeners. For some challenges, such as barriers to conducting site history and soil tests, some informants recommended city-wide interventions that bypass the need for gardener knowledge altogether.

Urban Community Gardeners' Knowledge and Perceptions of Soil Contaminant Risks

PubMed Central

Kim, Brent F.; Poulsen, Melissa N.; Margulies, Jared D.; Dix, Katie L.; Palmer, Anne M.; Nachman, Keeve E.

2014-01-01

Although urban community gardening can offer health, social, environmental, and economic benefits, these benefits must be weighed against the potential health risks stemming from exposure to contaminants such as heavy metals and organic chemicals that may be present in urban soils. Individuals who garden at or eat food grown in contaminated urban garden sites may be at risk of exposure to such contaminants. Gardeners may be unaware of these risks and how to manage them. We used a mixed quantitative/qualitative research approach to characterize urban community gardeners' knowledge and perceptions of risks related to soil contaminant exposure. We conducted surveys with 70 gardeners from 15 community gardens in Baltimore, Maryland, and semi-structured interviews with 18 key informants knowledgeable about community gardening and soil contamination in Baltimore. We identified a range of factors, challenges, and needs related to Baltimore community gardeners' perceptions of risk related to soil contamination, including low levels of concern and inconsistent levels of knowledge about heavy metal and organic chemical contaminants, barriers to investigating a garden site's history and conducting soil tests, limited knowledge of best practices for reducing exposure, and a need for clear and concise information on how best to prevent and manage soil contamination. Key informants discussed various strategies for developing and disseminating educational materials to gardeners. For some challenges, such as barriers to conducting site history and soil tests, some informants recommended city-wide interventions that bypass the need for gardener knowledge altogether. PMID:24516570

Influence of urban land cover changes and climate change for the exposure of European cities to flooding during high-intensity precipitation

NASA Astrophysics Data System (ADS)

Skougaard Kaspersen, P.; Høegh Ravn, N.; Arnbjerg-Nielsen, K.; Madsen, H.; Drews, M.

2015-06-01

The extent and location of impervious surfaces within urban areas due to past and present city development strongly affects the amount and velocity of run-off during high-intensity rainfall and consequently influences the exposure of cities towards flooding. The frequency and intensity of extreme rainfall are expected to increase in many places due to climate change and thus further exacerbate the risk of pluvial flooding. This paper presents a combined hydrological-hydrodynamic modelling and remote sensing approach suitable for examining the susceptibility of European cities to pluvial flooding owing to recent changes in urban land cover, under present and future climatic conditions. Estimated changes in impervious urban surfaces based on Landsat satellite imagery covering the period 1984-2014 are combined with regionally downscaled estimates of current and expected future rainfall extremes to enable 2-D overland flow simulations and flood hazard assessments. The methodology is evaluated for the Danish city of Odense. Results suggest that the past 30 years of urban development alone has increased the city's exposure to pluvial flooding by 6% for 10-year rainfall up to 26% for 100-year rainfall. Corresponding estimates for RCP4.5 and RCP8.5 climate change scenarios (2071-2100) are in the order of 40 and 100%, indicating that land cover changes within cities can play a central role for the cities' exposure to flooding and conversely also for their adaptation to a changed climate.

Paint study : progress report No. 1 : Louisiana highway research.

DOT National Transportation Integrated Search

1965-03-01

The principle objectives of this study are arrive at the most economical atmospheric paint system for structural steel and to correlate weatherometer exposure with atmospheric exposure. Three sites in Louisiana have been selected - they are Baton Rou...

GEONETCast Americas - Architecture

Science.gov Websites

Americas is a contribution from the United States National Oceanic and Atmospheric Administration whose Surveillance; Sustainable Urban Development and Water Resources Management. NOAA Privacy Policy Copyright 2008 © NOAA. All rights reserved. the National Oceanic and Atmospheric Administration (NOAA) Last

GEONETCast Americas - Architecture

Science.gov Websites

. GEONETCast Americas is a contribution from the United States National Oceanic and Atmospheric Administration Surveillance; Sustainable Urban Development and Water Resources Management. Privacy Act Statement Copyright 2008 © NOAA. All rights reserved. the National Oceanic and Atmospheric Administration (NOAA) Last

Contribution of Isoprene Epoxydiol to Urban Organic Aerosol: Evidence from Modeling and Measurements

EPA Science Inventory

In a region heavily influenced by anthropogenic and biogenic atmospheric emissions, recent field measurements have attributed one third of urban organic aerosol by mass to isoprene epoxydiols (IEPOX). These aerosols arise from the gas phase oxidation of isoprene, the formation of...

Ultrafine particles in cities.

PubMed

Kumar, Prashant; Morawska, Lidia; Birmili, Wolfram; Paasonen, Pauli; Hu, Min; Kulmala, Markku; Harrison, Roy M; Norford, Leslie; Britter, Rex

2014-05-01

Ultrafine particles (UFPs; diameter less than 100 nm) are ubiquitous in urban air, and an acknowledged risk to human health. Globally, the major source for urban outdoor UFP concentrations is motor traffic. Ongoing trends towards urbanisation and expansion of road traffic are anticipated to further increase population exposure to UFPs. Numerous experimental studies have characterised UFPs in individual cities, but an integrated evaluation of emissions and population exposure is still lacking. Our analysis suggests that the average exposure to outdoor UFPs in Asian cities is about four-times larger than that in European cities but impacts on human health are largely unknown. This article reviews some fundamental drivers of UFP emissions and dispersion, and highlights unresolved challenges, as well as recommendations to ensure sustainable urban development whilst minimising any possible adverse health impacts. Copyright © 2014 Elsevier Ltd. All rights reserved.

Bags with oven-dried moss for the active monitoring of airborne trace elements in urban areas.

PubMed

Giordano, S; Adamo, P; Monaci, F; Pittao, E; Tretiach, M; Bargagli, R

2009-10-01

To define a harmonized methodology for the use of moss and lichen bags as active monitoring devices of airborne trace elements in urban areas, we evaluated the element accumulation in bags exposed in Naples in different spring weather conditions for 6- and 12-weeks. Three different pre-exposure treatments were applied to moss and lichen materials: water-washing, acid-washing and oven-drying. During the different exposure periods in the Naples urban environment the moss accumulated always higher amounts of elements (except Hg) than lichens and the element accumulation increased during wetter weather and higher PM(10) conditions. The oven pre-treatment did not substantially modify the morphology and element composition of moss and the exposure in bags of this material for 6-weeks was sufficient to detect the pattern of airborne trace elements.

Sound Pollution-Another Urban Problem

ERIC Educational Resources Information Center

Breysse, Peter A.

1970-01-01

Suggests that sound pollution constitutes a severe problem to the urban dweller. Excessive exposure of humans to noise produces both physical and psychological manifestations. Suggests that control of industrial, aircraft, and community noise must be recognized and accepted as a major factor in urban planning and development. Bibliography. (LC)

A cross-sectional study of determinants of indoor environmental exposures in households with and without chronic exposure to biomass fuel smoke.

PubMed

Pollard, Suzanne L; Williams, D'Ann L; Breysse, Patrick N; Baron, Patrick A; Grajeda, Laura M; Gilman, Robert H; Miranda, J Jaime; Checkley, William

2014-03-24

Burning biomass fuels indoors for cooking is associated with high concentrations of particulate matter (PM) and carbon monoxide (CO). More efficient biomass-burning stoves and chimneys for ventilation have been proposed as solutions to reduce indoor pollution. We sought to quantify indoor PM and CO exposures in urban and rural households and determine factors associated with higher exposures. A secondary objective was to identify chronic vs. acute changes in cardiopulmonary biomarkers associated with exposure to biomass smoke. We conducted a census survey followed by a cross-sectional study of indoor environmental exposures and cardiopulmonary biomarkers in the main household cook in Puno, Peru. We measured 24-hour indoor PM and CO concentrations in 86 households. We also measured PM2.5 and PM10 concentrations gravimetrically for 24 hours in urban households and during cook times in rural households, and generated a calibration equation using PM2.5 measurements. In a census of 4903 households, 93% vs. 16% of rural vs. urban households used an open-fire stove; 22% of rural households had a homemade chimney; and <3% of rural households participated in a national program encouraging installation of a chimney. Median 24-hour indoor PM2.5 and CO concentrations were 130 vs. 22 μg/m3 and 5.8 vs. 0.4 ppm (all p<0.001) in rural vs. urban households. Having a chimney did not significantly reduce median concentrations in 24-hour indoor PM2.5 (119 vs. 137 μg/m3; p=0.40) or CO (4.6 vs. 7.2 ppm; p=0.23) among rural households with and without chimneys. Having a chimney did not significantly reduce median cook-time PM2.5 (360 vs. 298 μg/m3, p=0.45) or cook-time CO concentrations (15.2 vs. 9.4 ppm, p=0.23). Having a thatched roof (p=0.007) and hours spent cooking (p=0.02) were associated with higher 24-hour average PM concentrations. Rural participants had higher median exhaled CO (10 vs. 6 ppm; p=0.01) and exhaled carboxyhemoglobin (1.6% vs. 1.0%; p=0.04) than urban participants. Indoor air concentrations associated with biomass smoke were six-fold greater in rural vs. urban households. Having a homemade chimney did not reduce environmental exposures significantly. Measures of exhaled CO provide useful cardiopulmonary biomarkers for chronic exposure to biomass smoke.

A cross-sectional study of determinants of indoor environmental exposures in households with and without chronic exposure to biomass fuel smoke

PubMed Central

2014-01-01

Background Burning biomass fuels indoors for cooking is associated with high concentrations of particulate matter (PM) and carbon monoxide (CO). More efficient biomass-burning stoves and chimneys for ventilation have been proposed as solutions to reduce indoor pollution. We sought to quantify indoor PM and CO exposures in urban and rural households and determine factors associated with higher exposures. A secondary objective was to identify chronic vs. acute changes in cardiopulmonary biomarkers associated with exposure to biomass smoke. Methods We conducted a census survey followed by a cross-sectional study of indoor environmental exposures and cardiopulmonary biomarkers in the main household cook in Puno, Peru. We measured 24-hour indoor PM and CO concentrations in 86 households. We also measured PM2.5 and PM10 concentrations gravimetrically for 24 hours in urban households and during cook times in rural households, and generated a calibration equation using PM2.5 measurements. Results In a census of 4903 households, 93% vs. 16% of rural vs. urban households used an open-fire stove; 22% of rural households had a homemade chimney; and <3% of rural households participated in a national program encouraging installation of a chimney. Median 24-hour indoor PM2.5 and CO concentrations were 130 vs. 22 μg/m3 and 5.8 vs. 0.4 ppm (all p<0.001) in rural vs. urban households. Having a chimney did not significantly reduce median concentrations in 24-hour indoor PM2.5 (119 vs. 137 μg/m3; p=0.40) or CO (4.6 vs. 7.2 ppm; p=0.23) among rural households with and without chimneys. Having a chimney did not significantly reduce median cook-time PM2.5 (360 vs. 298 μg/m3, p=0.45) or cook-time CO concentrations (15.2 vs. 9.4 ppm, p=0.23). Having a thatched roof (p=0.007) and hours spent cooking (p=0.02) were associated with higher 24-hour average PM concentrations. Rural participants had higher median exhaled CO (10 vs. 6 ppm; p=0.01) and exhaled carboxyhemoglobin (1.6% vs. 1.0%; p=0.04) than urban participants. Conclusions Indoor air concentrations associated with biomass smoke were six-fold greater in rural vs. urban households. Having a homemade chimney did not reduce environmental exposures significantly. Measures of exhaled CO provide useful cardiopulmonary biomarkers for chronic exposure to biomass smoke. PMID:24655424

Testing a high resolution CO2 and CO emission inventory against atmospheric observations in Salt Lake City, Utah for policy applications

NASA Astrophysics Data System (ADS)

Mendoza, D. L.; Lin, J. C.; Mitchell, L.; Gurney, K. R.; Patarasuk, R.; Mallia, D. V.; Fasoli, B.; Bares, R.; Catharine, D.; O'Keeffe, D.; Song, Y.; Huang, J.; Horel, J.; Crosman, E.; Hoch, S.; Ehleringer, J. R.

2016-12-01

We address the need for robust highly-resolved emissions and trace gas concentration data required for planning purposes and policy development aimed at managing pollutant sources. Adverse health effects resulting from urban pollution exposure are the result of proximity to emission sources and atmospheric mixing, necessitating models with high spatial and temporal resolution. As urban emission sources co-emit carbon dioxide (CO2) and criteria air pollutants (CAPs), efforts to reduce specific pollutants would synergistically reduce others. We present a contemporary (2010-2015) emissions inventory and modeled CO2 and carbon monoxide (CO) concentrations for Salt Lake County, Utah. We compare emissions transported by a dispersion model against stationary measurement data and present a systematic quantification of uncertainties. The emissions inventory for CO2 is based on the Hestia emissions data inventory that resolves emissions at hourly, building and road-link resolutions, as well as on an hourly gridded scale. The emissions were scaled using annual Energy Information Administration (EIA) fuel consumption data. We derived a CO emissions inventory using methods similar to Hestia, downscaling total county emissions from the 2011 Environmental Protection Agency's (EPA) National Emissions Inventory (NEI). The gridded CO emissions were compared against the Hestia CO2 gridded data to characterize spatial similarities and differences between them. Correlations were calculated at multiple scales of aggregation. The Stochastic Time-Inverted Lagrangian Trasport (STILT) dispersion model was used to transport emissions and estimate pollutant concentrations at an hourly resolution. Modeled results were compared against stationary measurements in the Salt Lake County area. This comparison highlights spatial locations and hours of high variability and uncertainty. Sensitivity to biological fluxes as well as to specific economic sectors was tested by varying their contributions to modeled concentrations and calibrating their emissions.

Air quality in the megacity of São Paulo: Evolution over the last 30 years and future perspectives

NASA Astrophysics Data System (ADS)

Andrade, Maria de Fatima; Kumar, Prashant; de Freitas, Edmilson Dias; Ynoue, Rita Yuri; Martins, Jorge; Martins, Leila D.; Nogueira, Thiago; Perez-Martinez, Pedro; de Miranda, Regina Maura; Albuquerque, Taciana; Gonçalves, Fabio Luiz Teixeira; Oyama, Beatriz; Zhang, Yang

2017-06-01

We present a comprehensive review of published results from the last 30 years regarding the sources and atmospheric characteristics of particles and ozone in the Metropolitan Area of São Paulo (MASP). During the last 30 years, many efforts have been made to describe the emissions sources and to analyse the primary and secondary formation of pollutants under a process of increasing urbanisation in the metropolitan area. From the occurrence of frequent violations of air quality standards in the 1970s and 1980s (due to the uncontrolled air pollution sources) to a substantial decrease in the concentrations of the primary pollutants, many regulations have been imposed and enforced, although those concentrations do not yet conform to the World Health Organization guidelines. The greatest challenge currently faced by the São Paulo State Environmental Protection Agency and the local community is controlling secondary pollutants such as ozone and fine particles. Understanding the formation of these secondary pollutants, by experimental or modelling approaches, requires the description of the atmospheric chemical processes driven by biofuel, ethanol and biodiesel emissions. Exposure to air pollution is the cause of many injuries to human health, according to many studies performed not only in the region but also worldwide, and affects susceptible populations such as children and the elderly. The MASP is the biggest megacity in the Southern Hemisphere, and its specifics are important for other urban areas that are facing the challenge of intensive growth that puts pressure on natural resources and worsens the living conditions in urban areas. This text discusses how imposing regulations on air quality and emission sources, mainly related to the transportation sector, has affected the evolution of pollutant concentrations in the MASP.

Fine and ultrafine atmospheric particulate matter at a multi-influenced urban site: Physicochemical characterization, mutagenicity and cytotoxicity.

PubMed

Landkocz, Yann; Ledoux, Frédéric; André, Véronique; Cazier, Fabrice; Genevray, Paul; Dewaele, Dorothée; Martin, Perrine J; Lepers, Capucine; Verdin, Anthony; Courcot, Lucie; Boushina, Saâd; Sichel, François; Gualtieri, Maurizio; Shirali, Pirouz; Courcot, Dominique; Billet, Sylvain

2017-02-01

Particulate Matter (PM) air pollution is one of the major concerns for environment and health. Understanding the heterogeneity and complexity of fine and ultrafine PM is a fundamental issue notably for the assessment of PM toxicological effects. The aim of this study was to evaluate mutagenicity and cytotoxicity of a multi-influenced urban site PM, with or without the ultrafine fraction. For this purpose, PM 2.5-0.3 (PM with aerodynamic diameter ranging from 0.3 to 2.5 μm) and PM 2.5 were collected in Dunkerque, a French coastal industrial city and were extensively characterized for their physico-chemical properties, including inorganic and organic species. In order to identify the possible sources of atmospheric pollution, specific criteria like Carbon Preference Index (CPI) and PAH characteristic ratios were investigated. Mutagenicity assays using Ames test with TA98, TA102 and YG1041 Salmonella strains with or without S9 activation were performed on native PM sample and PM organic extracts and water-soluble fractions. BEAS-2B cell viability and cell proliferation were evaluated measuring lactate dehydrogenase release and mitochondrial dehydrogenase activity after exposure to PM and their extracts. Several contributing sources were identified in PM: soil resuspension, marine emissions including sea-salt or shipping, road traffic and industrial activities, mainly related to steelmaking or petro-chemistry. Mutagenicity of PM was evidenced, especially for PM 2.5 , including ultrafine fraction, in relation to PAHs content and possibly nitro-aromatics compounds. PM induced cytotoxic effects at relatively high doses, while alteration of proliferation with low PM doses could be related to underlying mechanisms such as genotoxicity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Aromatic VOCs global influence in the ozone production

NASA Astrophysics Data System (ADS)

Cabrera-Perez, David; Pozzer, Andrea

2016-04-01

Aromatic hydrocarbons are a subgroup of Volatile Organic Compounds (VOCs) of special interest in the atmosphere of urban and semi-urban areas. Aromatics form a high fraction of VOCs, are highly reactive and upon oxidation they are an important source of ozone. These group of VOCs are released to the atmosphere by processes related to biomass burning and fossil fuel consumption, while they are removed from the atmosphere primarily by OH reaction and by dry deposition. In addition, a branch of aromatics (ortho-nitrophenols) produce HONO upon photolysis, which is responsible of certain amount of the OH recycling. Despite their importance in the atmosphere in anthropogenic polluted areas, the influence of aromatics in the ozone production remains largely unknown. This is of particular relevance, being ozone a pollutant with severe side effects on air quality, health and climate. In this work the atmospheric impacts at global scale of the most emitted aromatic VOCs in the gas phase (benzene, toluene, xylenes, ethylbenzene, styrene, phenol, benzaldehyde and trimethylbenzenes) are analysed and assessed. Specifically, the impact on ozone due to aromatic oxidation is estimated, as this is of great interest in large urban areas and can be helpful for developing air pollution control strategies. Further targets are the quantification of the NOx loss and the OH recycling due to aromatic oxidation. In order to investigate these processes, two simulations were performed with the numerical chemistry and climate simulation ECHAM/MESSy Atmospheric Chemistry (EMAC) model. The simulations compare two cases, one with ozone concentrations when aromatics are present or the second one when they are missing. Finally, model simulated ozone is compared against a global set of observations in order to better constrain the model accuracy.