Showing papers on "Air pollutant concentrations published in 2001"

Effect of air pollution on daily mortality in Hong Kong.

Abstract: In different weather conditions, constituents and concentrations of pollutants, personal exposure, and biologic responses to air pollution may vary. In this study we assessed the effects of four air pollutants on mortality in both cool and warm seasons in Hong Kong, a subtropical city. Daily counts of mortality, due to all nonaccidental causes, and cardiovascular and respiratory diseases were modeled with daily pollutant concentrations [24-hr means for nitrogen dioxide, sulfur dioxide, and particulate matter 0.135). In this subtropical city, local air quality objectives should take into account that air pollution has stronger health effects during the cool rather than warm season and that oxidant pollutants are more important indicators of health effects than particulates.

The health effects of air pollution

Abstract: Chapter 11 of the book concentrates on the health effects of air pollution in the general population at normal ambient levels. It discusses factors to be considered in assessing the extensive literature on health effects and provides a brief summary of the effects on health of particulates, sulphur dioxide, nitrogen dioxide, ozone and carbon monoxide. It also addresses the possible relationship between air pollution and cancer. 103 refs., 1 fig., 2 tabs.

Microscopic Model of Air Pollutant Concentrations: Comparison of Simulated Results with Measured and Macroscopic Estimates

Abstract: Road traffic is a major source of air pollution, and substantial effort is currently being devoted to the development of both technological and transport policy measures to reduce the impacts. It is well established that the emission of certain pollutants is closely related to both traffic speed and fluctuations in traffic speed. However, conventional transport emission models are largely based on average traffic conditions, and thus they cannot properly represent the effects of policy measures, such as automatic speed control or traffic calming, that directly affect the speed dynamics of the traffic stream. Given the prevalence of such policies, there has been considerable effort to develop improved emissions modeling capabilities. A new approach to the microscopic modeling of air pollution from road traffic is described. This approach can represent detailed speed fluctuations in the flow of traffic, and it is applied to a local network in Maidstone, Kent, in the United Kingdom. A stochastic microscopic traffic flow simulation model (VISSIM), an existing speed-based emission database (MODEM), and a Gaussian dispersion model are combined. Simulated results are compared with a macroscopic model of air pollutant concentrations (DMRB method) and roadside pollutant measurements. Results are encouraging and show a good comparison with the DMRB method and, with some exceptions, good comparisons with trends in measured pollutant concentrations. Statistical differences in the methods, however, suggest that either measurement error or other inaccuracies are present.

Total Air Pollution And Space-Time Modelling

Abstract: Two general problems occur in the analysis of air pollution data; multiple contaminants and a dependence on both spatial location and time of observation. Principal Component Analysis (PCA) provides a tool for removing the interdependence of the contaminant concentrations, in addition an analysis of the principal components, eigenvectors and eigenvalues provides additional insight into the dispersion and occurrence of the pollution plume. New models for space-time variograms and techniques for modelling them have been introduced by De laco, Myers and Posa.

Hazardous Air Pollutant Source Emissions for a Chemical Fiber Manufacturing Facility in Taiwan

Abstract: The chemical and fiber industries in Taiwan are very importantcontributors to economic development of Taiwan over the past several decades, but it often associated with serious air pollution problems. The study was initiated in response to odorcomplaints from residents of neighborhoods located adjacent tothe largest chemical fiber manufacturing plant in Taiwan. The purposes of this article are: (1) to characterize the source emissions; (2) to quantify some odorous components and VOCs in the ambient air around the plant; and (3) to compare measured ambient concentrations of emitted compounds with Taiwan's guidelines for Hazardous Air Pollutant (HAP) ambient concentrations. Gas samples were analyzed for targetsulfurous and volatile organic compounds, e.g., sulfides, mercaptans, BTX, etc. Ambient samples were collected using Tenax adsorbent tubes for mass spectrometric analysis. On-site sampling and analysis was also conducted for SO2 by Continuous Emission Monitoring (CEM). The resulting measured ambient air concentrations were compared to published odor threshold limits and Taiwan's regulatory standards for hazardousair pollutants. Subsequently, a Gaussian dispersion model incorporating the measured data was applied to estimate the source emissions and provide advance warning to the affected neighborhoods. The factors controlling formation of the odors at the facility and in the residential neighborhoods were identified. Additionally, environmental conditions (wind speedand wind direction) that could affect concentrations of emission constituents were discussed.

Current Air quality problem and control strategies for vehicular emissions in China

Abstract: China has experienced very rapid economic development in recent yearsUrban air has very high concentrations of various pollutants, including sulphur dioxide (SO2), oxides of nitrogen (NOx), ozone (O3) and particulate. This paper reviews the changes in air quality in the cities like Guangzhou over the past 15 years, and notes that a serious vehicular-related emissions problem has been superimposed on the traditional coal-burning problem evident in most Chinese cities. As NOx concentrations have increased, oxidants and photochemical smog now interact with the traditional SO2 and particulate pollutants, leading to increased health risks and other environmental concerns. Any responsible NOx control strategy for the city must include vehicle emission control measures. This paper, using Guangzhou as a case, reviews control strategies designed to abate vehicle emissions to fulfill the city's air quality improvement target in 2010. A cost-effectiveness analysis suggests that, while NOx emission control is expensive, vehicular emission standards could achieve a relatively sizable emissions reduction at reasonable cost. To achieve the 2010 air quality target of NOx, advanced implementation of EURO3 standards is recommended, substituting for the EURO2 currently envisioned in the national regulations. Related technical options, including fuel quality improvements and inspection/maintenance (I/M) upgrades (to ASM or IM240), are assessed as well.

Control strategies for vehicular NOx emissions in Guangzhou, China

Abstract: Guangzhou is a city in southern China that has experienced very rapid economic development in recent years. The city's air has very high concentrations of various pollutants, including sulphur dioxide (SO2), oxides of nitrogen (NOx), ozone (O3) and particulate. This paper reviews the changes in air quality in the city over the past 15 years, and notes that a serious vehicular-related emissions problem has been superimposed on the traditional coal-burning problem evident in most Chinese cities. As NOx concentrations have increased, oxidants and photochemical smog now interact with the traditional SO2 and particulate pollutants, leading to increased health risks and other environmental concerns. Any responsible NOx control strategy for the city must include vehicle emission control measures. This paper reviews control strategies designed to abate vehicle emissions to fulfill the city's air quality improvement target in 2010. A cost-effectiveness analysis suggests that, while NOx emission control is expensive, vehicular emission standards could achieve a relatively sizable emissions reduction at reasonable cost. To achieve the 2010 air quality target of NOx, advanced implementation of EURO3 standards is recommended, substituting for the EURO2 currently envisioned in the national regulations. Related technical options, including fuel quality improvements and inspection/maintenance (I/M) upgrades (ASM or IM240), are assessed as well.

Hazardous air pollutants: inside and out.

Abstract: The Total Exposure Assessment Methodology (TEAM) Study, the National Human Exposure Assessment Surveys (NHEXAS), and the Cumulative Exposure Project (CEP) are titles of US Environmental Protection Agency (EPA) projects designed to measure or model complete, total human exposure to air pollutants in the pathways of ingestion, inhalation, or absorption to assess public health risks.1–3 Most researchers are aware that constraints such as funding, subject or data availability, and analytical techniques or sampling times may restrict projects and that regulatory programs impose even more restraints. But in total cumulative exposure studies researchers should try to align project designs with the expansive goals for at least one route of exposure. One of the first projects under the EPA CEP modeled hazardous air pollutants to estimate concentrations of each pollutant across the United States and to assess the impacts of these air toxins at the local census tract level.4 Design parameters restricted the study to choosing the 189 air pollutants listed in Section 112 of the 1990 Clean Air Act and to using 1990 as the base year to collect emissions data. The modeling results were used in estimating the health risks from the hazardous air pollutants by comparing health benchmark concentrations to the modeled concentrations. The conclusions, although problematic with the use of existing data, were stunning: in more than 90% of the census tracts, concentrations of benzene, formaldehyde, and 1,3 butadiene exceeded the cancer health benchmark.4,5 In “Evaluating the Health Significance of Hazardous Air Pollutants Using Monitoring Data” by Amy Kyle, PhD, MPH, et al., the authors used this modeling information to explore the completeness of air monitoring data and concluded that methods for assessing the public health impact of air pollutants are very rudimentary. They outline a list of recommendations for improvement.6 As ambitious and startling as these conclusions are for the CEP, they only provide information on the concentrations of the hazardous air pollutants outdoors. The levels of pollutants indoors were not addressed in these evaluations of air toxins. The authors of the cited paper do note that in many cases MaryBeth Smuts, PhDa

A Study on Synoptic Cause of Air Pollution and Forecast Methods of Air Pollutant Concentrations in Lanzhou Proper in Winter

Abstract: Lanzhou is one of the cities in which air pollution is very heavy. Based on the analysis on the relation between air pollution and climate element, the weather style in winter were given .The correlations between concentrations of three mainly air pollutants (TSP?SO2?NOX) and inversion parameter at the same times were analysised, the correlations between concentrations of air pollutants and surface meteorological elements were analysised too. The results show:(1) The correlation coefficients between air pollutant concentrations and thickness of inversion is positive.(2) The correlation coefficients between air pollutant concentrations and average of air temperature, relative humidity, horizontal visibility ,wind speed ,total cloud amount is negative. The correlation coefficients between air pollutant concentrations and difference between maximal air temperature and minimum air temperature is positive. As the result, air pollution concentration forecast equations were given for different weather style in winter. The examined results show that the forecast project has high accuracy.

[Effects of air pollution on daily mortality in the city of Zaragoza, Spain, 1991-1995].

Abstract: OBJECTIVE To analyze the short-term impact of air pollution on daily mortality in the City of Zaragoza (Spain). MATERIAL AND METHODS This ecologic study was conducted in Zaragoza, Spain, from 1991 to 1993. Poisson autoregressive models were constructed to assess the association between air particulate matter and sulphur dioxide SO2 and daily deaths. Four outcome variables were studied: overall mortality (excluding external deaths), mortality in subjects over 69 years of age, mortality due to respiratory disease, and mortality due to cardiovascular disease. A sample size was not obtained. Data analysis was conducted using the statistical software EGRET and SPSS. RESULTS SO2 levels were significantly associated with cardiovascular deaths (RR = 1.018 IC 95%: 1.001-1.036) and particulate matter levels with respiratory deaths (RR = 1.028 IC 95%: 1.006-1.051). During the warm season, a significant relationship was found between particulate mater and cardiovascular deaths (RR = 1.020 IC 95%: 1.001-1.040). CONCLUSIONS Low levels of air pollution were found in Zaragoza, with considerable variation in the concentration of air pollutant concentrations and daily respiratory and cardiovascular deaths, particularly during the warm season. The English version of this paper is available at: http://www.insp.mx/salud/index.html

Sampling for estimation of air pollution levels and air pollution environmental effects

Abstract: Introduction In Europe, the impetus for control of transboundary air pollution has been the detrimental effects of the pollutants on both human health and on the state of the environment. In assessing the environmental effects the difficult issue is to estimate the damage to a particular species or to an ecosystem. For example, the major European controls on sulphur emissions followed the loss of fish from Scandinavian lakes and the association with acidity of the water. However, in many circumstances, air pollution does not lead immediately to easily observable loss of species or ecosystem change. The effects of pollutants can often be cumulative within the ecosystem and pollution damage may be seen as a change in growth rate of a plant or an increased susceptibility to damage from other stresses such as frost. In complex ecosystems, the extrapolation of the results from controlled laboratory or field experiments can be misleading, especially if complex interactions between vegetation and soils are the most important factors in determining actual damage. When studying ecosystem damage, colocated sampling for air pollution levels and vegetation effects is optimal but can be difficult to implement. Vegetation sampling on a specific day or on several days over a longer period is relatively easy and low cost. The plants, however, may have accumulated air pollutants either through rainfall or by direct gas uptake over a much longer time scale. The air pollution monitoring necessary to determine that uptake (or deposition) can be quite costly and may require effort over an extended period. National or regional air pollution monitoring networks will predict pollution levels over large areas and there is a cost benefit in using this data in place of local monitoring. However the sampling strategy for these networks has been decided on different criteria, and the link between the vegetation sampling strategy and the monitoring network strategy becomes crucial. Sampling to detect vegetation effects is of little value if the uncertainty in pollution model predicted exposure is too large. In all deposition models the pollutant concentration is critical in estimating deposition. The behaviour of the chemical species in the atmosphere is important when choosing how to monitor pollutant concentration levels. Emitted sulphur dioxide mainly returns through the wet deposition of sulphate in rain, which has often remained in the atmosphere for 3 to 6 days and has travelled 3000 to 5000 km from source. Therefore the rainfall sulphate concentrations are expected to be spatially quite smooth and sampling sites may be well spaced out. By contrast, ammonia gas has a very short residence time in the atmosphere, travelling only the order of 1 km in a few minutes. This leads to highly variable concentrations in source areas and very intensive spatial monitoring would be required. In this paper, three air pollution monitoring networks will be considered in terms of their ability to support vegetation and ecosystem sampling studies.