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Published 1988 | public
Journal Article

Basinwide nitric acid and related species concentrations observed during the Claremont nitrogen species comparison study

Abstract

In conjunction with the Claremont Nitrogen Species Comparison Study, tandem filter units designed to collect HNO_3/total aerosol (TA) NO_3− and NH_3/TA NH+_4 were operated at seven locations throughout the Los Angeles area, including Claremont. The sampling methods used were related to the comparison study via intensive short-term and long-term measurements made at Claremont by both the tandem filter method and the denuder difference method. Between methods, 4-h and 6-h duration HNO_3 samples taken by the tandem filter method were higher (~ 20%) than the HNO_3 results obtained by the denuder difference method. As sampling duration increased to 22 h, the tandem filter method HNO_3 and NH_3 concentration measurements increased, while the 22-h denuder difference method HNO_3 values remained indistinguishable from the average of simultaneous short-term 4- and 6-h average samples. Analysis of the basinwide data showed that Claremont experienced the highest measured HNO_3 concentrations in the Los Angeles area during the period of the comparison study, confirming that Claremont was a wise choice for the main site of the study. In contrast, an alternative site near Riverside experienced the lowest HNO_3 levels in the air basin, accompanied by high aerosol nitrate and very high NH_3 concentrations.

Additional Information

© 1988 Pergamon Press plc. First received 24 November 1986 and in final form 11 August 1987. This work was supported by the California Air Resources Board under Agreement A4-144-32. Thanks are due to the South Coast Air Quality Management District for allowing the use of their air monitoring sites.

Additional details

Created:
August 19, 2023
Modified:
October 26, 2023