(611c) A Smog Chamber Investigation of Aerosols Produced From Soil, Water and Vegetation

The atmospheric oxidation of volatile organic compounds (VOCs) produces a wide array of condensable organic compounds, which can partition to the aerosol phase. Although Köhler theory can be used to predict the cloud activation of inorganic particles, the significance of organic compounds or their identities is still unknown and needs further exploration.  This research has investigated the contributions of soils, waters and vegetation found in the Susquehanna River Bioregion to the rural background aerosol and the main properties of these aerosol particles such as their concentration, size and shape and their ability to interact with water vapor. We have sampled several common trees and shrubs, local soils, and river water from the Susquehanna River over the course of two summers.  These samples were collected fresh and placed promptly in a one cubic meter smog chamber where they were exposed various levels of ozone.  Oxidation products of the natural VOCs emitted partition into the particulate phase and were measured over time to determine the number and concentration of aerosols produced.  Some of the aerosol particles were collected on substrates for imaging using an Atomic Force Microscope (AFM).  The aerosols produced were also measured for water interactions using both Hygroscopic Tandem Differential Mobility Analysis (HTDMA) and a Cloud Condensation Nucleus Counter (CCNC).