| Hydrocarbons in the atmosphere undergo oxidation that can lead to the formation of semi-volatile products. These products undergo gas-to-particle conversion to form secondary organic aerosol (SOA). Reaction chambers provide a controlled environment in which gas-to-particle conversion is investigated. First, an extensive investigation into the aerosol forming potential of 14 biogenic hydrocarbons is reported.; Traditionally, chamber experiments have been performed at relative humidity levels such that the aerosol investigated is water-free. However, atmospheric conditions are typically such that ambient aerosol contains water. A new facility to improve measurement of SOA formation under humid conditions is described. A comprehensive study on how the presence of water affects gas-to-particle partitioning in the α-pinene ozonolysis and m-xylene and mesitylene photooxidation systems is reported.; The diurnal trends in the hygroscopic nature of Pasadena, CA, aerosol is reported for late summer, 1999. Presented are additional investigations into the identification of products resulting from ozonolysis of α-pinene, β-pinene, sabinene, Δ3-carene, and cyclohexene. A field campaign to identify similar monoterpene oxidation products in a forest environment is presented. Finally, an estimate of the global aerosol burden from biogenic hydrocarbons is provided. |
