Development of long term sulfur di oxide monitor using permeation sampling
Mcdermott, D.L.; Reiszner, K.D.; West, P.W.
Environmental Science and Technology 13(9): 1087-1090
ISSN/ISBN: 0013-936X Accession: 005134154
A method was developed for monitoring integrated or time-weighted average SO2 concentration for weeks or even months. The approach is based on the quantitative permeation of gaseous SO2 through a dimethylsilicone polymer membrane into a Mn salt solution, which subsequently stabilizes the collected SO2 by catalytic oxidation to H2SO4. Like the lead peroxide candle method, the permeation procedure does not require the use of pumps or motors and the product is photochemically and thermally stable. Unlike the lead peroxide candle, which produces only relative SO2-sulfation effect measurements, the newly developed method provides absolute quantitation in terms of concentration and is SO2 specific, humidity independent and functional over a wide temperature range. The detection limit is 10 .mu.g/m3 for a 7 day exposure period. Exposure periods as great as 3 mo. are possible.