The monitoring of acidic dry deposition has posed significant logistical and technical problems that must be overcome as part of our national effort to accurately characterize and understand acid precipitation patterns. The sampling equipment in widespread use today has as its technological basis many features of a 50-year-old rainfall collector, modified to include dry sample collection. A sampling device, advanced by recent NASA research, has the potential for more widespread application with minimal additional development. This device, the "electret," is a small, passive sampler designed to retain air contaminants to which it is exposed and to be analyzed for chemical composition by a mass spectrometer. Although the contaminants targeted by NASA were rocket exhaust effluent gases and particles, those of concern in this study are the acidic constituents of dry atmospheric deposition. The technological gap that remains in the development and use of the electret, even by NASA, is a calibration procedure that will permit a quantitative interpretation of the chemical results. This research will develop a calibration procedure that can then be used to demonstrate that the electret is a viable candidate for use in measuring acidic dry deposition.Anticipated Results/Potential Commercial Applications as described by the awardee:This study will provide a calibration technique to be used in quantifying the individual chemical species collected by an electret. Although much broader applications are foreseen in agriculture, industry, and environmental protection, the initial emphasis will be directed toward identifying and quantifying the dry constituents of acid precipitation.
