Polar organic compounds measured in fine particulate matter during TexAQS 2000

Abstract

Fine particle samples were collected at three sites in the Houston area during TexAQS 2000. Polar organic species including levoglucosan, n -alkanoic acids, n -alkenoic acids and dicarboxylic acids were quantified to characterize the composition of local ambient organic aerosols. Levoglucosan, a tracer for biomass burning, was measured as a dominant compound, followed by n -alkanoic acids. The compound distribution of higher molecular weight n -alkanoic acids (⩾C 22 ) was consistent with biogenic emission sources. n -Alkenoic acids exhibit variable concentrations during sampling period with high ratios of octadecanoic to octadecenoic acid. The concentrations of dicarboxylic acids are compared with unapportioned organic carbon calculated by the chemical mass balancing technique. This correlation supports the conclusion that diacids are generated by photochemical reactions and contribute to the unapportioned organic mass. Data collected during a regional wood smoke episode are used to examine the influence of wood combustion to ambient particulate matter concentrations.