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AEROSOL ACIDITY CHARACTERIZATION OF LARGE METROPOLITAN AREAS: PILOT AND PLANNING FOR PHILADELPHIA
Citation:
Waldman, J., R. Burton, W. Wilson, L. Purdue, AND D. Pahl. AEROSOL ACIDITY CHARACTERIZATION OF LARGE METROPOLITAN AREAS: PILOT AND PLANNING FOR PHILADELPHIA. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/A-93/002 (NTIS PB93149177).
Description:
The majority of data on atmospheric levels of acidic particles has been produced in just the past few years. hile it is not known that acidic sulfate concentrations (24-h) can be as high as 25 ug m-3 in the rural and suburban regions of the eastern U.S. and Canada, few measurements have been performed in urban centers. n order to determine the potential effects on the total population, accurate exposure determinations are needed, especially here the highest density of people occur. n these populated areas, it is hypothesized that acidic particle exposures would be attenuated by anthropogenic ammonia. he U.S. Environmental Protection Agency, Harvard School of Public Health and Robert Wood Johnson Medical School have developed a multi-year program to investigate the specific issues affecting human exposures to aerosol acidity. he program -- called the Aerosol Acidity Characterization of Large Metropolitan Areas -- will include ambient measurements for a network of sites overlaying a metropolitan area, indoor monitoring in homes, offices and schools, samplers for roadway/vehicle exposures, plus studies of aerosol neutralization potential in human microenvironment. hiladelphia has been chosen as the first city in the program. t is a large metropolitan area in the heart of the northeastern seaboard afflicted with photochemical regional smog during the summertime. ilot study of ambient concentrations was performed in July 1991. n annular denuder system (ADS) sampler was operated for two weeks near downtown Philadelphia, with a second unit operated in central, suburban Kev Jersey, the sane location of measurements in past years. he Philadelphia site was found to have higher concentrations of most major aerosol species, ammonia and acidic particles than in New Jersey. ence, these early data do not support speculation that aerosol neutralization within the urban center will necessarily totally eliminate acidic particle exposures.