Showing papers on "Air pollutant concentrations published in 2014"

Air concentrations of volatile compounds near oil and gas production: a community-based exploratory study

Abstract: Background: Horizontal drilling, hydraulic fracturing, and other drilling and well stimulation technologies are now used widely in the United States and increasingly in other countries. They enable increases in oil and gas production, but there has been inadequate attention to human health impacts. Air quality near oil and gas operations is an underexplored human health concern for five reasons: (1) prior focus on threats to water quality; (2) an evolving understanding of contributions of certain oil and gas production processes to air quality; (3) limited state air quality monitoring networks; (4) significant variability in air emissions and concentrations; and (5) air quality research that misses impacts important to residents. Preliminary research suggests that volatile compounds, including hazardous air pollutants, are of potential concern. This study differs from prior research in its use of a community-based process to identify sampling locations. Through this approach, we determine concentrations of volatile compounds in air near operations that reflect community concerns and point to the need for more fine-grained and frequent monitoring at points along the production life cycle. Methods: Grab and passive air samples were collected by trained volunteers at locations identified through systematic observation of industrial operations and air impacts over the course of resident daily routines. A total of 75 volatile organics were measured using EPA Method TO-15 or TO-3 by gas chromatography/mass spectrometry. Formaldehyde levels were determined using UMEx 100 Passive Samplers. Results: Levels of eight volatile chemicals exceeded federal guidelines under several operational circumstances. Benzene, formaldehyde, and hydrogen sulfide were the most common compounds to exceed acute and other health-based risk levels. Conclusions: Air concentrations of potentially dangerous compounds and chemical mixtures are frequently present near oil and gas production sites. Community-based research can provide an important supplement to state air quality monitoring programs.

Air quality concerns of unconventional oil and natural gas production

Abstract: Increased use of hydraulic fracturing (“fracking”) in unconventional oil and natural gas (O & NG) development from coal, sandstone, and shale deposits in the United States (US) has created environmental concerns over water and air quality impacts. In this perspective we focus on how the production of unconventional O & NG affects air quality. We pay particular attention to shale gas as this type of development has transformed natural gas production in the US and is set to become important in the rest of the world. A variety of potential emission sources can be spread over tens of thousands of acres of a production area and this complicates assessment of local and regional air quality impacts. We outline upstream activities including drilling, completion and production. After contrasting the context for development activities in the US and Europe we explore the use of inventories for determining air emissions. Location and scale of analysis is important, as O & NG production emissions in some US basins account for nearly 100% of the pollution burden, whereas in other basins these activities make up less than 10% of total air emissions. While emission inventories are beneficial to quantifying air emissions from a particular source category, they do have limitations when determining air quality impacts from a large area. Air monitoring is essential, not only to validate inventories, but also to measure impacts. We describe the use of measurements, including ground-based mobile monitoring, network stations, airborne, and satellite platforms for measuring air quality impacts. We identify nitrogen oxides, volatile organic compounds (VOC), ozone, hazardous air pollutants (HAP), and methane as pollutants of concern related to O & NG activities. These pollutants can contribute to air quality concerns and they may be regulated in ambient air, due to human health or climate forcing concerns. Close to well pads, emissions are concentrated and exposure to a wide range of pollutants is possible. Public health protection is improved when emissions are controlled and facilities are located away from where people live. Based on lessons learned in the US we outline an approach for future unconventional O & NG development that includes regulation, assessment and monitoring.

Criteria Air Pollutants

Abstract: This web area will provide access to information on setting and implementing the outdoor air quality standards for the six criteria air pollutants.

Modification of the effect of ambient air pollution on pediatric asthma emergency visits: susceptible subpopulations.

Abstract: Epidemiologic and experimental research supports the conclusion that certain outdoor air pollutants cause exacerbations of asthmatic symptoms among children with asthma.1,2 Similarly, there is a growing body of literature describing how in utero and early life experiences affect physiological development and influence sensitivity to environmental factors throughout life.3 Unfortunately, most large population-based studies of associations between short-term changes in ambient air pollutant concentrations and asthma exacerbations have lacked data on early-life risk factors, whereas the cohort studies that include such information are often too small to support investigation of effect-measure modification among potentially susceptible subgroups. In the U.S. state of Georgia, data on live birth records have been linked with pediatric emergency department visits by staff at the Office of Health Indicators for Planning at the Georgia Department of Public Health. Additionally, in metropolitan Atlanta there are several long-running air quality measurement campaigns that include, among other more commonly measured pollutants, daily measurements from four monitoring stations of speciated particulate matter less than 2.5 microns in diameter (PM2.5). We used these two data resources to estimate the rate ratio (RR) relating short-term changes in air pollutant concentrations to emergency department (ED) visits for asthma or wheeze and to investigate whether there was evidence for effect-measure modification of the RR by various risk factors available from the linked dataset. Although we examined effect-measure modification for eight different factors, we had particular a priori interest in investigating whether susceptibility might have varied by gestational age, as accumulating evidence suggests that children born preterm have long-term decrements in lung function.4,5

Modelling of human exposure to air pollution in the urban environment: a GPS-based approach

Abstract: The main objective of this work was the development of a new modelling tool for quantification of human exposure to traffic-related air pollution within distinct microenvironments by using a novel approach for trajectory analysis of the individuals. For this purpose, mobile phones with Global Positioning System technology have been used to collect daily trajectories of the individuals with higher temporal resolution and a trajectory data mining, and geo-spatial analysis algorithm was developed and implemented within a Geographical Information System to obtain time–activity patterns. These data were combined with air pollutant concentrations estimated for several microenvironments. In addition to outdoor, pollutant concentrations in distinct indoor microenvironments are characterised using a probabilistic approach. An example of the application for PM2.5 is presented and discussed. The results obtained for daily average individual exposure correspond to a mean value of 10.6 and 6.0–16.4 μg m−3 in terms of 5th–95th percentiles. Analysis of the results shows that the use of point air quality measurements for exposure assessment will not explain the intra- and inter-variability of individuals’ exposure levels. The methodology developed and implemented in this work provides time-sequence of the exposure events thus making possible association of the exposure with the individual activities and delivers main statistics on individual’s air pollution exposure with high spatio-temporal resolution.

The effects of energy paths and emission controls and standards on future trends in China's emissions of primary air pollutants

Abstract: . To examine the efficacy of China's actions to control atmospheric pollution, three levels of growth of energy consumption and three levels of implementation of emission controls are estimated, generating a total of nine combined activity-emission control scenarios that are then used to estimate trends of national emissions of primary air pollutants through 2030. The emission control strategies are expected to have more effects than the energy paths on the future emission trends for all the concerned pollutants. As recently promulgated national action plans of air pollution prevention and control (NAPAPPC) are implemented, China's anthropogenic pollutant emissions should decline. For example, the emissions of SO2, NOx, total suspended particles (TSP), PM10, and PM2.5 are estimated to decline 7, 20, 41, 34, and 31% from 2010 to 2030, respectively, in the "best guess" scenario that includes national commitment of energy saving policy and implementation of NAPAPPC. Should the issued/proposed emission standards be fully achieved, a less likely scenario, annual emissions would be further reduced, ranging from 17 (for primary PM2.5) to 29% (for NOx) declines in 2015, and the analogue numbers would be 12 and 24% in 2030. The uncertainties of emission projections result mainly from the uncertain operational conditions of swiftly proliferating air pollutant control devices and lack of detailed information about emission control plans by region. The predicted emission trends by sector and chemical species raise concerns about current pollution control strategies: the potential for emissions abatement in key sectors may be declining due to the near saturation of emission control devices use; risks of ecosystem acidification could rise because emissions of alkaline base cations may be declining faster than those of SO2; and radiative forcing could rise because emissions of positive-forcing carbonaceous aerosols may decline more slowly than those of SO2 emissions and thereby concentrations of negative-forcing sulfate particles. Expanded control of emissions of fine particles and carbonaceous aerosols from small industrial and residential sources is recommended, and a more comprehensive emission control strategy targeting a wider range of pollutants (volatile organic compounds, NH3 and CO, etc.) and taking account of more diverse environmental impacts is also urgently needed.

Dispersion modeling of traffic-related air pollutant exposures and health effects among children with Asthma in Detroit, Michigan

Abstract: Vehicular traffic is a major source of ambient air pollution in urban areas. Traffic-related air pollutants, including carbon monoxide, nitrogen oxides, particulate matter less than 2.5 μm in diameter, and diesel exhaust emissions, have been associated with adverse human health effects, especially in areas near major roads. In addition to emissions from vehicles, ambient concentrations of air pollutants include contributions from stationary sources and background (or regional) sources. Although dispersion models have been widely used to evaluate air quality strategies and policies and can represent the spatial and temporal variation in environments near roads, the use of these models in health studies to estimate air pollutant exposures has been relatively limited. This paper summarizes the modeling system used to estimate exposures in the Near-Roadway Exposure and Urban Air Pollutant Study, an epidemiological study that examined 139 children with asthma or symptoms consistent with asthma, most of whom li...

Artificial intelligence modeling to evaluate field performance of photocatalytic asphalt pavement for ambient air purification

Abstract: In recent years, the application of titanium dioxide (TiO2) as a photocatalyst in asphalt pavement has received considerable attention for purifying ambient air from traffic-emitted pollutants via photocatalytic processes. In order to control the increasing deterioration of ambient air quality, urgent and proper risk assessment tools are deemed necessary. However, in practice, monitoring all process parameters for various operating conditions is difficult due to the complex and non-linear nature of air pollution-based problems. Therefore, the development of models to predict air pollutant concentrations is very useful because it can provide early warnings to the population and also reduce the number of measuring sites. This study used artificial neural network (ANN) and neuro-fuzzy (NF) models to predict NOx concentration in the air as a function of traffic count (Tr) and climatic conditions including humidity (H), temperature (T), solar radiation (S), and wind speed (W) before and after the application of TiO2 on the pavement surface. These models are useful for modeling because of their ability to be trained using historical data and because of their capability for modeling highly non-linear relationships. To build these models, data were collected from a field study where an aqueous nano TiO2 solution was sprayed on a 0.2-mile of asphalt pavement in Baton Rouge, LA. Results of this study showed that the NF model provided a better fitting to NOx measurements than the ANN model in the training, validation, and test steps. Results of a parametric study indicated that traffic level, relative humidity, and solar radiation had the most influence on photocatalytic efficiency.

The relationship between air pollution and asthma in Malaysian schoolchildren

Abstract: Rapid increases in traffic volumes in countries such as Malaysia may lead to exposure to poor air quality both outdoors and indoors. This study investigated asthma symptoms among Malaysian schoolchildren in relation to indoor and outdoor air pollution in urban and semi-rural settings in a school-based cross-sectional study of 1,952 schoolchildren living in urban and semi-rural areas. Parents completed a questionnaire including questions on asthma symptoms and environmental risk factors. Air pollutant concentrations were measured at 16 schools. Analysis used multiple logistic regression controlling for sociodemographic and indoor air pollution factors. A total of 11.4, 7.6, 9.5 and 7.0 % schoolchildren had asthma, current wheeze, dry cough at night and wheezing after exercise, respectively. Asthma and dry cough were significantly higher among urban schoolchildren. A 10-μg/m3 increase in outdoor NO2 level was associated with a twofold increase in the reporting of current wheeze (odds ratio (OR) 1.90; 95 % confidence interval (CI) 1.02–3.52); a 10-μg/m3 increase in indoor PM2.5 was similarly associated with a twofold increase in the reporting of wheeze during exercise (OR 2.08; 95 % CI 1.02–4.26). Secondhand smoke (SHS), mold and the presence of new furniture at home were also linked to asthma symptoms. NO2 concentrations in urban Malaysia frequently exceed those of the international standards. Exposure to traffic-related air pollution may be linked to asthma symptoms among children in Malaysia.

National Air Quality: Status and Trends of Key Air Pollutants

Abstract: EPA sets national air quality standards for six common air pollutants. Each year EPA tracks the levels of these air pollutants in the air. EPA posts the results of our analyses to this web site.

Air pollution and greenhouse gases

Abstract: Air pollution and greenhouse gases : , Air pollution and greenhouse gases : , کتابخانه دیجیتال جندی شاپور اهواز

Air Pollutant Emissions

Abstract: This chapter discusses the emissions of air pollutants form various sources, including from stationary and mobile sources, as well as from personal sources. Combustion is considered from the perspective of its contribution to air pollution, especially the emissions of products of incomplete combustion. The ways that emissions are regulated and their risks reduced are described. These include traditional emission controls, as well as emissions trading approaches. Examples of calculating and predict emissions are described, including the rollback and receptor models. Recent changes in fuels are described, including the lead (Pb) phase-outs, as well as new formulations to decrease emissions of sulfur, ash, and hydrocarbons. Air toxics emissions are discussed, as well as emission inventories and emission factors.

Process analysis of a regional air pollution episode over Pearl River Delta region, China, using the MM5-CMAQ model.

Abstract: This study focuses on the influences of a warm high-pressure meteorological system on aerosol pollutants, employing the simulations by the Models-3/CMAQ system and the observations collected during October 10–12, 2004, over the Pearl River Delta (PRD) region. The results show that the spatial distributions of air pollutants are generally circular near Guangzhou and Foshan, which are cities with high emissions rates. The primary pollutant is particulate matter (PM) over the PRD. MM5 shows reasonable performance for major meteorological variables (i.e., temperature, relative humidity, wind direction) with normalized mean biases (NMB) of 4.5–38.8% and for their time series. CMAQ can capture one peak of all air pollutant concentrations on October 11, but misses other peaks. The CMAQ model systematically underpredicts the mass concentrations of all air pollutants. Compared with chemical observations, SO2 and O3 are predicted well with a correlation coefficient of 0.70 and 0.65. PM2.5 and NO are significantly u...

Modeling study on atmospheric environmental capacity of major pollutants constrained by PM_(2.5) compliance of Chinese cities

Abstract: An iterative algorithm was developed to assess the atmospheric environmental capacity governed by air quality targets, based on the third generation air quality model WRF-CAMx and national emission inventory of major air pollutants. The atmospheric environmental capacity of SO2, NOx, primary PM2.5 and NH3 emissions by provinces were calculated with the constrain of annual average ambient PM2.5 concentration standard(GB3095-2012). The results indicated that the national carrying capacity of SO2, NOx, primary PM2.5 and NH3 emissions was 1363.26×104t, 1258.48×104t, 619.04×104t, and 627.71×104t. The actual emissions of SO2, NOx, primary PM2.5 and NH3 in year 2010 were 66%, 81%, 96%, and 52% higher than the carring capacity. The emissions of these four types of air pollutants came from provinces that were severely polluted, such as Henan, Hebei, Tianjin, Anhui, Shandong, and Beijing, were exceeded 100% over its carrying capacity.

Major factors influencing the health impacts from controlling air pollutants with nonlinear chemistry: an application to China.

Abstract: Predicting the human-health effects of reducing atmospheric emissions of nitrogen oxide (NOx) emissions from power plants, motor vehicles, and other sources is complex because of nonlinearity in the relevant atmospheric processes. We estimate the health impacts of changes in fine particulate matter (PM2.5) and ozone concentrations that result from control of NOx emissions alone and in conjunction with other pollutants in and outside the mega-city of Shanghai, China. The Community Multiscale Air Quality (CMAQ) Modeling System is applied to model the effects on atmospheric concentrations of emissions from different economic sectors and geographic locations. Health impacts are quantified by combining concentration-response functions from the epidemiological literature with pollutant concentration and population distributions. We find that the health benefits per ton of emission reduction are more sensitive to the location (i.e., inside vs. outside of Shanghai) than to the sectors that are controlled. For eastern China, we predict between 1 and 20 fewer premature deaths per year per 1,000 tons of NOx emission reductions, valued at $300-$6,000 per ton. Health benefits are sensitive to seasonal variation in emission controls. Policies to control NOx emissions need to consider emission location, season, and simultaneous control of other pollutants to avoid unintended consequences.

Screening the weekdays/weekend patterns of air pollutant concentrations recorded in southeastern romania

Abstract: Some of the major stressors of air quality in the urban areas are nitrogen oxides, ozone and suspended particles. The effect of air pollution on respiratory diseases can increase considerably at high levels of pollution and might trigger asthma symptoms. Longterm exposure can increase the rate of respiratory infections and symptoms at population level, but particularly in children. The goal was to analyze with statistical techniques the pollutant concentrations (NO, NO2, and SO2) recorded by 15 automated monitoring stations, to establish weekdays-weekend trends in various towns of the South Muntenia Region during cold months when residential heating contributes to the overall emissions. Raw data of the monitored parameters were acquired from 7 stations for NO and NO2, and 14 stations for SO2. Data acquisition and processing were performed between November 15, 2013 and February 28, 2014 and hourly-recorded time series were characterized for central tendency, dispersion and distribution. The statistical analysis determined the degree of differentiation between different sites and time intervals of the monitored pollutants using the screening of air quality trends based on hourly concentrations of each weekday using a specific grouping of data. The results support the characterization of weekday/weekend patterns in air pollutant concentrations in several urban areas of Southern Romania, where air pollution data were available: 4 cities (NO, NO2) i.e., Ploiesti, Slobozia, Turnu Magurele, and Giurgiu, respectively 6 cities (SO2), i.e., Ploiesti, Pitesti, Cimpulung, Giurgiu, Alexandria and Turnu Magurele.

Measurement of spatial and temporal variation in volatile hazardous air pollutants in Tacoma, Washington, using a mobile membrane introduction mass spectrometry (MIMS) system

Abstract: The objective of this study was to use membrane introduction mass spectrometry (MIMS), implemented on a mobile platform, in order to provide real-time, fine–scale, temporally and spatially resolved measurements of several hazardous air pollutants. This work is important because there is now substantial evidence that fine-scale spatial and temporal variations of air pollutant concentrations are important determinants of exposure to air pollution and adverse health outcomes. The study took place in Tacoma, WA during periods of impaired air quality in the winter and summer of 2008 and 2009. Levels of fine particles were higher in winter compared to summer, and were spatially uniform across the study area. Concentrations of vapor phase pollutants measured by membrane introduction mass spectrometry (MIMS), notably benzene and toluene, had relatively uniform spatial distributions at night, but exhibited substantial spatial variation during the day—daytime levels were up to 3-fold higher at traffic-impacted loca...

Effect of ventilation on distributions, concentrations, and emissions of air pollutants in a manure-belt layer house

Abstract: Air pollutants from poultry operations pose a potential threat not only for bird health, but also for the environment outside. Ventilation is believed to be an effective way of regulating house environment. To improve understanding of ventilation effects on house environment, distributions, concentrations and emissions of ammonia, carbon dioxide, total suspended particulates, and particulate matter 2.5 (fine particles with a diameter of 2.5 μm or less) were investigated in a manure-belt layer house using 9 ventilation stages (VS) with different ventilation rates (VT). Distributions of pollutants were assessed visually using contour plots and coefficient of variation. Emission rates of pollutants were estimated by multiplying VT by concentration. Spatial distributions of 4 pollutants were not homogeneous throughout the house, regardless of VS, and increased VT aggravated the spatial disparity. In the house, pollutant concentrations were controlled under harmful levels during the 9 VS. Ventilation, as expected, can decrease pollutant concentrations. However concentrations of ammonia and carbon dioxide did not decrease proportionately to increased VT. The highest emission rates of 4 pollutants were observed during VS1, a stage with maximum ventilation, which reflected VT as a key factor determining emission rate. The study indicated that it is difficult to balance house environment and control pollutant concentrations depending only on ventilation. Several additional factors, such as temperature, humidity, manure handling, bird management, and ventilation system design, should be comprehensively considered to control air pollutants from poultry operations.

Air Quality Status and Trends

Abstract: This chapter describes the condition of air quality, based on air pollutant concentrations, i.e. criteria pollutants, in airsheds around the world, as well as certain air toxics in urban areas and hot spots. The variability of pollutant concentrations in space and time are discussed, as well as differences in air pollution between more industrialized and economically developed regions vs developing nations. The status and trends of atmospheric concentrations of tropospheric ozone, oxides of nitrogen, oxides of sulfur, carbon monoxide, lead, and particulate matter are discussed. Examples of air toxics include benzene, polycyclic aromatic hydrocarbons, dioxins, aldehydes, and metals, e.g. mercury. Regional and global trends include acid deposition, depletion of the stratospheric ozone layer, and climate change. Indoor air quality is discussed. The chapter concludes with a description of an air quality index.