Organic Functional Group Composition and Sources of Ambient Aerosol during CalNex 2010 Amanda Frossard, Lynn Russell, Scripps Institution of Oceanography, UC San Diego Timothy Bates, and Patricia Quinn Pacific Marine Environmental Laboratory, NOAA Photo Credit: P.M. Shaw
Overview Organic Aerosol Collection and Quantification Organic Mass Composition Technique Comparison PMF Source Contributions Single Particle Composition Potential Source Locations Photo Credit: P.M. Shaw
Organic Aerosol Sampling Mass Flow Meter and Controller Total: 16.8 lpm Vacuum Pump PM1 Cyclone 2 pairs of Teflon filters Dried to 55% RH
Organic Aerosol Sampling Four Sampling Regions: Southern California Coastal Transit San Francisco Sacramento
Organic Mass Composition Southern California Coastal Transit San Francisco Sacramento
Overall Organic Mass Composition Ratio of O/C: 0.46 μg m -3 Total OM: 1.64 μg m -3 – Alcohol: 0.26 μg m -3 (16%) – Acid: 0.51 μg m -3 (31%) – Alkane: 0.83 μg m -3 (51%) – Amine: 0.05 μg m -3 (3%) Southern California Coastal Transit San Francisco Sacramento 2.11 μg m μg m μg m μg m -3
Technique Comparison Q-AMS OM = 0.83*FTIR OM r = 0.82 Lower OM in the Q-AMS could be due to organics on dust, submicron sea salt, or other refractory particles
Source Contributions More oxygenated “aged” 76% of OM Less oxygenated “fresh” 12% of OM
Source Contributions Southern California Coastal Transit San Francisco Sacramento
Combustion Factors Less oxygenated More oxygenated Russell et al. 2011, in press
Oxygenated Combustion Factor r = 0.82 Expect that most sulfate is secondary, so correlation with OM suggests the OM is also SOA
Single Particles: Sacramento Combustion Secondary
Single Particles: LA Harbor Combustion Secondary
Source Contributions Organic Mass Carboxylic Acid Concentration
Source Contributions Aged Combustion Fresh Combustion
Summary Average organic mass: 1.64 μg m -3 Two combustion sources – More oxygenated (76% of OM) – Less oxygenated Single Particle analysis – Secondary and combustion particles OM from continental sources
Thanks! Acknowledgements: Scientists and crew of R/V Atlantis The LBNL Beamline group Russell group Dan Czizco and PNNL PMEL and Uva Atlantis Groups