Aerosol mass spectrometric characterization of ambient organic particles: new techniques and field results (Invited Speaker)

Aerosols play major roles in climate forcing and the hydrological cycle, and also on human health effects, visibility degradation, and deposition of acids, toxics, and nutrients to ecosystems. Organic aerosols (OA) account for a large fraction (~40%) of ambient submicron aerosol mass, but their sources and transformation processes remain poorly understood. The Aerodyne Aerosol Mass Spectrometers (AMS) have emerged as powerful tools for the characterization of organic aerosols due to their sensitivity, speed, and quantitative ability. Recent AMS and related instrumental and analysis technique developments from our group will be summarized including the determination of OA components/sources from high-resolution mass spectrometry, the first measurements of chemically-resolved volatility in two megacities, the comparison of SOA measurements with several 3D and box models, and the aging of biomass burning aerosols in laboratory and field studies. Results from several recent field campaigns, including the recent MILAGRO campaign in Mexico City and the ARCTAS campaign in Alaska, Northern Canada, and Greenland, will be presented.