Apportionment of primary and secondary organic aerosols in southern California during the 2005 study of organic aerosols in riverside (SOAR-1).
Ambient sampling was conducted in Riverside, California during the 2005 Study of Organic Aerosols in Riverside to characterize the composition and sources of organic aerosol using a variety of state-of-the-art instrumentation and source apportionmenttechniques. The secondary organic aerosol (SOA) mass is estimated by elemental carbon and carbon monoxide tracer methods, water soluble organic carbon content, chemical mass balance of organic molecular markers, and positive matrix factorization of high-resolution aerosol mass spectrometer data. Estimates obtained from each ofthese methods indicate that the organic fraction in ambient aerosol is overwhelmingly secondary in nature during a period of several weeks with moderate ozone concentrations and that SOA is the single largest component of PM1 aerosol in Riverside. Average SOA/OA contributions of 70-90% were observed during midday periods, whereas minimum SOA contributions of approximately 45% were observed during peak morning traffic periods. These results are contraryto previous estimates of SOAthroughout the Los Angeles Basin which reported that, other than during severe photochemical smog episodes, SOA was lower than primary OA. Possible reasons for these differences are discussed.
Docherty
Kenneth S
KS
Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA.
Stone
Elizabeth A
EA
Ulbrich
Ingrid M
IM
DeCarlo
Peter F
PF
Snyder
David C
DC
Schauer
James J
JJ
Peltier
Richard E
RE
Weber
Rodney J
RJ
Murphy
Shane M
SM
Seinfeld
John H
JH
Grover
Brett D
BD
Eatough
Delbert J
DJ
Jimenez
Jose L
JL
D000336:Aerosols / Q000032:analysis*; D002140:California; D002244:Carbon / Q000737:chemistry; D002248:Carbon Monoxide / Q000737:chemistry; D013058:Mass Spectrometry; D009930:Organic Chemicals / Q000032:analysis*; D045483:Rivers / Q000737:chemistry*; D012995:Solubility; D014867:Water / Q000737:chemistry
D000336:Aerosols; D009930:Organic Chemicals; D014867:Water; D002244:Carbon; D002248:Carbon Monoxide