Sulfate and Nitrate Particulates as Related to SO2 and NOX Gases and Emissions

Abstract

Five years (1969-1973) of sulfate and nitrate fractions were analyzed from high-volume particulate samples at 8 stations in the San Francisco Bay Area. These particulate data have been compared with simultaneous SO2 and NOx gas data and emission inventory data. On an annual basis, the sulfate and nitrate particulates closely track the emission inventory data, while the gas data vary more widely in response to local sources and to meteorological factors. The area-wide five year mean for sulfates is 2.68 µ/m3, only slightly above the remote nonurban sulfate background level. However, the similar five year nitrate mean of 2.78 µ/m3 is well above the national urban average. On isolated occasions, when extreme cold required "in-terruptible" sources to switch from natural gas to fuel oil, both sulfate and nitrate fractions showed 24 hour values in excess of 20 µ/m3. © 1976 Air & Waste Management Association.