Halocarbon distributions and relationships in Asian outflow and US urban regions: Observations from TRACE-P, ITCT, and TEXAQS 2000 airborne samples

Atmospheric trace gas composition and temporal trends are ultimately linked to specific source emissions, transport pathways, and deposition or destruction rates in the atmosphere. Recent airborne studies have been conducted to better characterize and compare the chemical composition of outflow from regions heavily impacted by anthropogenic activity, including industrialization, biofuel and biomass combustion, as well as natural emissions. The NASA GTE TRACE-P study examined large-scale continental outflow from Asia to the Pacific Ocean atmosphere; the NOAA ITCT and TEXAQS 2000 studies examined, among other objectives, chemical characteristics of specific urban emission sources in the continental US. Whole air samples collected during all of these missions were analyzed for a large variety of organic trace gases, including NMHC, organic nitrates, halocarbons, and selected sulfur species. This presentation focuses on the halocarbon distributions and relationships observed in the different source regions. The halocarbons examined include HCFCs, HFCs, Halons, and solvents. These compounds contribute to the changing burden of anthropogenic chlorine in the troposphere and the stratosphere.