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 QuinnPacific 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 ControllerTotal: 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 CompositionSouthern 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 Sacramento2.11 μg m-3 0.51 μg m-3 0.58 μg m-3 0.78 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 ContributionsSouthern California Coastal Transit San Francisco Sacramento
Combustion FactorsLess 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 HarborCombustion
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