AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Investigating Chemical Variation in Particulate Matter during the Polarimetric Cloud Analysis and Seeding Test (POLCAST) 2012 Campaign in Grand Forks, North Dakota
RICHARD COCHRAN, Haewoo Jeong, David Delene, Alena Kubatova, University of North Dakota
Abstract Number: 479 Working Group: Aerosol Chemistry
Abstract Organic material accounts for a large fraction of particulate matter (PM) in the atmosphere and can have an influence on our climate. Additionally many organic constituents within the organic fraction have been attested to various negative effects on human health. The sources of the thousands of compounds typically present within PM include primary emissions through various anthropogenic and natural sources as well as through oxidation pathways leading to secondary organic products or SOA. Chemical variation among PM in different environments is a product of different primary emission sources as well as the extent to which secondary oxidation reactions occur. While many natural and anthropogenic primary emission sources have been evaluated in terms of their contribution to the chemical fingerprint of PM studies, the data assessing the contribution of harvesting activities on chemical variance is limited. In this work we investigate organic (OC) and elemental (EC) carbon content as well as the chemical speciation of PM filter samples collected in weekly cycles through a sixteen week campaign in Grand Forks, ND. Filter collection began in early summer and extended through the local harvesting season during late summer/early fall. Filter samples were collected in parallel with PM measurements from a scanning mobility particle sizer, tapered-element oscillating microbalance, and a cloud condensation nuclei counter. OC and EC content of all filters samples were determined using a thermal optical analyzer. For chemical speciation of the collected filter samples a thermal desorption/pyrolysis-gas chromatography/mass spectrometry method was deployed. Variations in classes of compounds (i.e., alkanes, alkenes, polycyclic aromatic hydrocarbons and their oxidation products, etc.) and individual species throughout the campaign were evaluated.