Estimating pollutant exposures from coal fired power plants in a rural region

Abstract

A critical issue in epidemiological studies of ambient air pollution is the measurement of pollutant exposure in the study population. Accurate characterization of air quality is necessary in any study relating exposure to health effects, and is essential in attempting to quantify risk estimates for specific exposure concentrations. Despite the importance of accurate air quality data, most epidemiological investigations have used relatively crude estimates of pollutant exposure. Results from such investigations may be only qualitative at best.

Early studies of air pollution health effects were limited by a lack of air pollution monitoring sites, and thus, exposures were often based on surrogate measures such as tons of coal consumed. With the introduction of reliable and reasonably accurate measurements of pollutant concentrations, several important constraints remained. These limitations include the relatively sparse siting of monitor sites and the variable relationship of monitor concentrations to the exposure experience of the study population. Other considerations in using monitor data include the selection of the pollutant specie(s), the duration of the sampling period, the use of short-term versus long-term averages, peak versus mean concentrations and the cyclical variation in pollutant levels.

The Chestnut Ridge region of Pennsylvania is the site of an ongoing study of health effects from air pollution. This site was selected in part because of the extensive and well maintained air pollution monitoring network, and the previous studies of pollutant dispersion in the area. Several studies of respiratory symptoms and pulmonary function in women and school age children have been carried out in the area. The current study evaluated aspects of air pollution exposure estimates which are relevant to these epidemiologic studies. Subsequent papers will discuss findings of the various epidemiologic studies which employ these air pollution measures.