Studies of environmental acid deposition require monitoring of very low levels of several atmospheric pollutants. Various passive and active samplers have been used to collect integrated atmospheric samples for such studies. Continuous analyzers offer an advantage because of their capability to provide more detailed information on the diurnal concentration patterns of the pollutants of interest. The U. S. EPA acquired two continuous NO2 analyzer models (CSI 1600 and Scintrex LMA 3) and one SO2 analyzer model (TECO 43S) with sufficient sensitivity to be potentially useful in studies of acid deposition. In the laboratory evaluation, performance parameters such as precision, limit of detection and interferences were quantitated. In the 31-day field evaluation, zero and span factor drafts and precision were quantitated. The results of the laboratory and field evaluations are given in the report. Although EPA has not established performance specifications for extrasensitive analyzers, the results of the laboratory and field evaluations suggest that the analyzers, generally, will perform in an acceptable fashion for the intended application. Nevertheless, several specific areas needing improvement were uncovered in the evaluations.

Caption title. At head of title: Project summary. "Sept. 1990." "EPA/600/S3-90/034." Microfiche.