AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Occurrence of Volatiles and Larger Molecular Weight Compounds in Organic Particulate Matter Using Thermal Desorption – Pyrolysis – Gas Chromatography/Mass Spectrometry
BRETT NESPOR, Richard Cochran, Haewoo Jeong, David Delene, Alena Kubatova, Evguenii I. Kozliak, University of North Dakota
Abstract Number: 777 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Atmospheric particulate matter (PM) consisting of both organic carbon (OC) and elemental carbon (EC) has been known to have an effect on the public’s overall health as well as the radiation balance of Earth’s atmosphere. To understand the impact of harvesting activity on the composition of PM in the atmosphere, chemical speciation and total carbon content of PM was analyzed during the Polarimetric Cloud Analysis and Seeding Test (POLCAST) in Grand Forks, ND. Concentrations of OC and EC were determined using thermal optical analysis. Speciation of the OC fraction of PM was assessed using thermal desorption and pyrolysis coupled with gas chromatography mass spectrometry (TD-pyr-GC/MS). Thermal desorption (300 °C) and pyrolytic (˃ 500 °C) temperature programs were used to profile alkanes, alkenes and a variety of other organic compounds to investigate their sources. While the TD revealed speciation of volatile organics, the pyrolytic temperatures were associated with specific higher molecular weight species. Harvesting activities appeared to be related to an increased concentration of alkanes with prevalence of longer chain n-alkanes (waxes) with an odd number of carbons, indicating biogenic origins. Alkenes were abundant in the pyrolytic fractions of the analysis, indicating breakdown of these high chain alkanes, and presumably other lipids. Furthermore, organic tracers from both anthropogenic and biogenic processes were detected, including the burning of biomass and plastics.