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SPECIATION OF AMBIENT SULFATE PARTICULATE MATTER USING FTIR-BASED ABSORPTION TO COMPLEMENT WET CHEMICAL AND THERMAL DECOMPOSITION MEASUREMENTS
Citation:
McClenny, W. AND K. Krost. SPECIATION OF AMBIENT SULFATE PARTICULATE MATTER USING FTIR-BASED ABSORPTION TO COMPLEMENT WET CHEMICAL AND THERMAL DECOMPOSITION MEASUREMENTS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-94/449 (NTIS PB95131157), 1994.
Description:
The direct, nondestructive, infrared transmission measurement of fine articles on Teflon filters is used to unambiguously identify ammonium bisulfate in article samples collected from the ambient air. he samples are collected at 10 L/mi. over 23 hours f or 24 consecutive simmer days (21 July - 14 August) in 1991 in a rural setting near State College, PA. hese measurements are combined with the wet chemical analysis of the collected particles to infer the partition of particulate sulfate as g-onium sulfate, ammonium bisulfate, and sulfate associated with excess free hydrogen ion. he effects of particle reactions on the filter in altering the speciation are estimated by comparison of these results with the averaged real-time results obtained by thermal speciation. or 5 days when unusually high sulfuric acid concentrations occurred, particle reactions between sulfuric acid and ammonium sulfate apparently occurred on the filters producing ammonium bisulfate. ome neutralization of acid sulfate during processing of the filters is also suggested. ighly variable sulfate speciation is observed on a 24-hour basis, including sulfuric acid and ammonium sulfate without ammonium bisulfate. ulfate as ammonium sulfate, ammonium bisulfate and sulfuric acid exists in the proportions: 6.5 : 5.5 : 1 for the overall study. xcess sulfate as sulfuric acid occurs at 30-40 nmoles/m3 for averaged 24-hour concentrations.
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SPECIATION OF AMBIENT SULFATE PARTICULATE MATTER USING FTIR-BASED ABSORPTION TO COMPLEMENT WET CHEMICAL AND THERMAL DECOMPOSITION MEASUREMENTS