Ozone production in transpacific Asian pollution plumes and implications for ozone air quality in California

作者：R. C. Hudman, D. J. Jacob, Owen R. Cooper, M. J. Evans, Colette L. Heald, Rokjin J. Park, F. C. Fehsenfeld, F. Flocke, John W. Holloway, G. Hübler, Kazuyuki Kita, M. Koike, Y. Kondo, J. A. Neuman, J. B. Nowak, S. J. Oltmans, D. D. Parrish, J. M. Roberts, Thomas B. Ryerson · 发表于：Journal of Geophysical Research Atmospheres · 年份：2004 · DOI：10.1029/2004jd004974 · 被引用次数：239 · 研究领域：Atmospheric chemistry and aerosols、Atmospheric Ozone and Climate、Air Quality and Health Impacts

We examine the ozone production efficiency in transpacific Asian pollution plumes, and the implications for ozone air quality in California, by using aircraft and surface observations in April–May 2002 from the Intercontinental Transport and Chemical Transformation 2002 (ITCT 2K2) campaign off the California coast and the Pacific Exploration of Asian Continental Emission–B (PEACE‐B) campaign over the northwest Pacific. The observations are interpreted with a global three‐dimensional chemical transport model (GEOS‐CHEM). The model reproduces the mean features observed for CO, reactive nitrogen oxides (NOy), and ozone but underestimates the strong (∼20 ppbv) stratospheric contribution to ozone in the middle troposphere. The ITCT 2K2 aircraft sampled two major transpacific Asian pollution plumes, one on 5 May at 5–8 km altitude with CO up to 275 ppbv but no elevated ozone and one on 17 May at 2.5–4 km altitude with CO up to 225 ppbv and ozone up to 90 ppbv. We show that the elevated ozone in the latter plume is consistent with production from peroxyacetylnitrate (PAN) decomposition during subsidence of the plume over the northeast Pacific. This production is particularly efficient because of the strong radiation and low humidity of the subsiding environment. We argue that such PAN decomposition represents a major and possibly dominant component of the ozone enhancement in transpacific Asian pollution plumes. Strong dilution of Asian pollution plumes takes place during entrainmen...