Abstract

Nitrous oxide levels in the atmosphere are increasing, potentially contributing to the greenhouse effect and depletion of stratospheric ozone. From a limited data base, combustion sources have been identified as a major anthropogenic source of N2O. However, the existing data base is in question due to the discovery of a sampling artifact. A continuous on-line N2O analyzer would enable and facilitate the accurate characterization of combustion sources over a range of operating conditions, and also aid in the development of an appropriate sampling technique. This paper addresses the development of a continuous measurement technique, and the evaluation and initial use of a field prototype continuous N2O analyzer developed at the UCI Combustion Laboratory in cooperation with a major instrument manufacturer. The analyzer is capable of measuring N2O levels down to a few ppm. The analyzer has been evaluated and used to study the N2O emissions from a pulverized coal-fired boiler. The N2O levels found with the analyzer are substantially lower than levels previously attributed to such sources. Initial N2O measurements made with the analyzer suggest that N2O levels are not a substantial fraction of the NOx levels, as previously suggested. © 1989 Air & Waste Management Association.