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

摘要: [1] We examine the ozone production efficiency in transpacific Asian pollution plumes, and implications for air quality California, by using aircraft surface observations April–May 2002 from Intercontinental Transport Chemical Transformation (ITCT 2K2) campaign off California coast Pacific Exploration of Continental Emission–B (PEACE-B) over northwest Pacific. The are interpreted with a global three-dimensional chemical transport model (GEOS-CHEM). reproduces mean features observed CO, reactive nitrogen oxides (NOy), but underestimates strong (20 ppbv) stratospheric contribution to middle troposphere. ITCT 2K2 sampled two major one on 5 May at 5–8 km altitude CO up 275 ppbv no elevated 17 2.5–4 225 90 ppbv. show that latter plume is consistent peroxyacetylnitrate (PAN) decomposition during subsidence northeast This particularly efficient because radiation low humidity subsiding environment. argue such PAN represents possibly dominant component enhancement plumes. Strong dilution plumes takes place entrainment U.S. boundary layer, greatly reducing their impact sites. mountain sites more sensitive exposure free Model results indicate 7 Sequoia National Park those days when 8-hour average concentration exceeded 80 INDEX TERMS: 0368 Atmospheric Composition Structure: Troposphere—constituent chemistry; 0365 Troposphere—composition 0345 Pollution—urban regional (0305); KEYWORDS: ozone, pollution, 2K2, PEACE-B,