Source Signatures of Organic Compounds in the Particle Phase in Bakersfield, CA

SHANG LIU (1), Douglas Day (1), Lynn Russell (1)

Scripps Institution of Oceanography, University of California, San Diego, California

     Abstract Number: 589
     Last modified: May 14, 2010

Abstract
Submicron particles were collected in May and June of 2010 in Bakersfield, CA during the CalNex 2010 field campaign. Fourier Transform Infrared (FTIR) measurements of infrared absorbance characterized the functional groups associated with major carbon types, including alkane, carboxylic acid, alcohol, amine, non-acid carbonyl, organonitrate, alkene, and aromatic functional groups. Non-refractory organic fragments, ammonium, sulfate, nitrate, and chloride measurements using a High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) showed that organics contributed to a large fraction of PM1. Scanning Transmission X-ray Microscopy (STXM) and Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy were used to characterize single-particle functional group abundances. Positive Matrix Factorization (PMF) was applied to both FTIR and AMS measured OM. The factor time series were correlated with source indicators as measured by X-Ray Fluorescence (XRF) to identify sources contributing to organic functional groups. Potential Source Contribution Function (PSCF) was used to identify the likely geophysical locations of the PMF factors and to facilitate identification of the sources. The results suggest that organic mass has several distinct source types in the polluted regions, with fossil fuel combustion and biomass burning being the dominant sources.