Spatial variation in acidic sulfate concentrations within metropolitan Philadelphia

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:197320

Burton, R M ^[1]; Suh, H H; Allen, G A; Koutrakis, P ^[2]

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1. Environmental Protection Agency, Research Triangle Park, NC (United States). Atmospheric Research and Exposure Assessment Lab.
2. Harvard Univ., Boston, MA (United States). School of Public Health

Acidic sulfate concentrations were measured in metropolitan Philadelphia during the summer of 1992, as part of a continuing effort to characterize acid aerosol and gas concentrations in urban environments. Sampling was performed simultaneously at six sites located within metropolitan Philadelphia, a site located in Cambden, New Jersey, and at a rural site approximately 18 miles from the city center. Sites were selected based on their population density and on their relative locations within Philadelphia. Acid aerosol and gas sampling was performed on alternate days, with all samples collected for 12-hour periods beginning at 8 AM. All samples were collected using modified Harvard-EPA Annular Denuder Systems (HEADS). In this paper, the authors examine the spatial variation in acidic sulfate and ammonia concentrations within metropolitan Philadelphia. They also examine factors that may influence their variation. Outdoor sulfate concentrations were found to be uniform across metropolitan Philadelphia; however, considerable spatial variation in both aerosol strong acidity (H{sup +}) and ammonia (NH{sub 3}) concentrations was observed. This variation was found to be independent of wind direction and other regional factors, but related to local factors, such as population density and distance from the center of the city. These results suggest that models must consider local factors in order to estimate outdoor H{sup +} concentrations accurately for urban environments.

• OSTI ID: 197320
• Report Number(s): CONF-9405167--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AIR POLLUTION
AIR POLLUTION MONITORING
AIR POLLUTION MONITORS
AMMONIA
ECOLOGICAL CONCENTRATION
PENNSYLVANIA
SULFATES
URBAN AREAS