Air pollutant concentrations

About: Air pollutant concentrations is a research topic. Over the lifetime, 1652 publications have been published within this topic receiving 36138 citations.

Regional Scale Dispersion Modeling and Analysis of Directly Emitted Fine Particulate Matter from Mobile Source Pollutants Using AERMOD

Abstract: Author(s): Contreras, Seth Daniel | Advisor(s): McNally, Michael G | Abstract: A large and growing body of literature associates proximity to major roadways with increased risk of many negative health outcomes and suggests that exposure to fine particulate matter may be a substantial factor. Directly emitted and non-reactive mobile source air pollutants such as directly emitted fine particulate matter can form large spatial concentration gradients along major roadways, in addition to causing significantly large temporal and seasonal variation in air pollutant concentrations within urban areas. Current modeling and regulatory approaches for minimizing exposure have limited spatial resolution and do not fully exploit the available data.The objective is to establish a methodology for quantifying fine particulate matter concentration gradients due to mobile source pollutants and to estimate the resulting population exposure at a regional scale. A novel air dispersion modeling framework is proposed using the Environmental Protection Agency's regulatory model AERMOD with data from a regional travel demand model that can produce a high resolution concentration surface for a considerably large metropolitan area; in our case, Los Angeles County, California. We find that PM2.5 concentrations are highest and most widespread during the morning and evening commutes, particularly during the winter months. This is likely caused by a combination of stable atmospheric conditions during the early morning and after sunset in the evening and higher traffic volumes during the morning and evening commutes. During the midday hours concentrations are at their lowest even though traffic volumes are still much higher than during the evening. This is likely the result of heating during the day time which leads to unstable atmospheric conditions that cause more vertical mixing and lateral dispersion, reducing ground level PM2.5 concentrations by transport and dilution. With respect to roadway centerlines, PM2.5 concentrations drop off quickly, reaching relatively low concentrations between 150m to 200m from the center line of high volume roads. However, during stable atmospheric conditions (e.g., nighttime a winter season) concentrations remain elevated at distances up to 1,000m from roadway centerlines.We will demonstrate the feasibility of our methodology and how integrating the dispersion modeling framework into the travel demand modeling process routinely performed when developing and analyzing regional transportation improvement initiatives can lead to more environmentally and financially sustainable transportation plans. Regional strategies that minimize exposure, rather than inventories, could be established, environmental justice concerns are easily identified, and projects likely to cause local pollution "hotspots" can be proactively screened out, saving time and money for the transportation agency.

Monitoring of Gaseous Air Pollution

Abstract: Air pollution can be defined as the presence in the atmosphere of one or more contaminants in such quality and for such duration as is injurious, or tends to be injurious, to human health or welfare, animal or plant life. It is the contamination of air by the discharge of harmful substances. Industrialization have led to air getting more and more polluted over the years. Industries, vehicles, increase in the population, and urbanization are some of the major factors responsible for air pollution. The following industries are among those that emit a great deal of pollutants into the air: thermal power plants, cement, steel, refineries, petro chemicals, and mines. Air pollution can cause health problems and it can also damage the environment and property. It has caused thinning of the protective ozone layer of the atmosphere, which is leading to climate change. The source of pollution may be in one country but the impact of pollution may be felt elsewhere. The discovery of pesticides in Antarctica, where they have never been used, suggests the extent to which aerial transport can carry pollutants from one place to another. The most important tools in environmental protection is monitoring and modeling. Both the monitoring and modeling of air pollution is essential to provide a picture of the damage humans are doing to the environment, and to enable pollution problems to be discovered and dealt with. An environmental monitoring could be defined as a system of detection, measurements, evaluations and forecasts of environmental states, and the collecting, processing and spreading of information on the environment. Air pollution and its control is a global issue demanding international cooperation. Monitoring of air pollution is a very important source of data. However, measurement of the air pollutant concentrations, in comparison to monitoring of other elements in the environment, is the most difficult. The difficulties arise from the large dynamics of the atmosphere, causing that it constitutes the main route of pollution spreading and their transport between remaining environmental compartments and universal exposure for a large population without a chance for isolation, which is possible in the case of polluted waters and soil. Another problem is low concentration of air pollutants and their interaction with other gases. This chapter is divided into two parts. In the first, a general information on gaseous air pollution, parameters used to characterize the pollution level and equipment applied for air

An Air Quality Impact Assessment for the Proposed Development of Stansted Airport

Abstract: SUMMARY The results of an air quality impact assessment conducted in 1980, for the proposed development of Stansted airport, Essex, to a capacity of 15 million passengers per annum, are presented. Air pollutant concentrations measured in the vicinity of the airport were found to be low in comparison to ambient air quality guidelines and also when compared with other airports and urban areas. Atmospheric dispersion modelling to predict future emissions and ambient concentrations of air pollutants revealed that air quality standards would be unlikely to be infringed and that concentrations would be generally within the range of those measured at Gatwick airport in 1979.

Transportation and Air Quality in California: A Policy Analysis

Abstract: Significant accomplishments in air pollution emissions control have occurred over the past twenty years Emissions have been substantially reduced by both industrial and transportation sources; over the ten year period 1977-86, the US Environmental Protection Agency (EPA) reports improvements in each of the six air pollutants for which health-based national ambient air quality standards (NAAQS) exist -- lead, sulfur dioxide, ozone, carbon monoxide, nitrogen dioxide, and particulates Yet major problems remain: