organic functional group composition and sources of ambient aerosol during calnex 2010 amanda...

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