Dry deposition and dew chemistry in Claremont, California, during the 1985 nitrogen species methods comparison study
Abstract
Dry deposition of HNO_3 and aerosol nitrate in Claremont, California, during the September 1985 Nitrogen Species Methods Comparison Study was evaluated by means of nylon and Teflon surrogate-surface collectors. Dew chemistry and deposition to dew were also investigated. The nitrate dry deposition was governed largely by HNO_3; most of the dry deposition of inorganic nitrate (defined here as HNO_3(g) plus aerosol nitrate) onto the surrogate collectors occurred in the daytime, reflecting chiefly a greater-than-10-fold diurnal variation in ambient HNO_3 (g) concentration. In the absence of dew, deposition velocities were ~1.3cms^(−3) for HNO_3(g), ~0.2cms^(−1) for aerosol nitrate, and 0.5cms^(−1) for nitrate without distinction between the two species. Night-time nitrate deposition velocities appeared to be lower when there was dew. The total titratable acidity of the dew, though considerable (~ 50 μM), was not present chiefly as free acidity (H^+); the average pH was only ~ 5. Preliminary evidence suggests that some of the titratable dew acidity was derived from organic acids. These results are compared to dry deposition and dew chemistry in other areas.
Additional Information
© 1988 Pergamon Press. First received 24 November 1986 and in final form 29 May 1987. We are grateful to Prof. C. Freeman Allen and to the many others at Pomona College who provided us with the space and facilities for conducting this work and who cheerfully provided assistance at every turn. We are grateful to the California Air Resources Board for the opportunity to participate in the Comparison Study. We wish to thank Norman L. Eatough, of the California State Polytechnic University, San Luis Obispo, California, and also Delbert J. Eatough and Nelson Lytle, of Brigham Young University, for putting their ion chromatograph at our disposal in Claremont and assisting in its use; J. William Munger, of the California Institute of Technology, for assistance with the organic-acid ion-chromatographic analyses; and Susan M. Larson, of Cal Tech, for her role in the Cal Tech atmospheric measurements.Additional details
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- CaltechAUTHORS:20160713-083052464
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2016-07-27Created from EPrint's datestamp field
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2021-11-11Created from EPrint's last_modified field
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