A solid sorbent for collecting atmospheric SO2 was evaluated as part of an overall effort to develop a replacement method for the West-Gaeke method presently used to measure 24-hour ambient sulfur dioxide concentrations in ambient air. Research showed that a solid sorbent, consisting of Puramer S coated open cell polyurethane foam, can be used to fix the quantities of sulfur dioxide that would be collected if typical ambient air was filtered for 24 hours at 200 cc/min. The method of assaying sulfur dioxide collected by the sorbent consisted of controlled thermal desorption of sulfur dioxide followed by continuous analysis using a Dohrmann microcoulometric titration system. Troublesome sulfur dioxide decay, occuring during post collection storage, was primarily the result of oxidation. Decay was minimized, to an acceptable level, by properly sealing the spent Puramer S collector devices to prevent oxygen contamination from contacting the sorbent prior to thermal desorption and subsequent assaying.

"EPA-600/2-79-205." EPA contract no. 68-02-1782; EPA project officer: James Mulik. Includes bibliographical references (page 34).