title: Unspeciated organic emissions from combustion sources and their influence on the secondary organic aerosol budget in the United States.
abstract: Secondary organic aerosol (SOA) formed from the atmospheric oxidation of nonmethane organic gases (NMOG) is a major contributor to atmospheric aerosol mass. Emissions and smog chamber experiments were performed to investigate SOA formation from gasoline vehicles, diesel vehicles, and biomass burning. About 10-20% of NMOG emissions from these major combustion sources are not routinely speciated and therefore are currently misclassified in emission inventories and chemical transport models. The smog chamber data demonstrate that this misclassification biases model predictions of SOA production low because the unspeciated NMOG produce more SOA per unit mass than the speciated NMOG. We present new source-specific SOA yield parameterizations for these unspeciated emissions. These parameterizations and associated source profiles are designed for implementation in chemical transport models. Box model calculations using these new parameterizations predict that NMOG emissions from the top six combustion sources form 0.7 Tg y(-1) of first-generation SOA in the United States, almost 90% of which is from biomass burning and gasoline vehicles. About 85% of this SOA comes from unspeciated NMOG, demonstrating that chemical transport models need improved treatment of combustion emissions to accurately predict ambient SOA concentrations.
authors.affiliation: Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA 15213; and.
authors.forename: Shantanu H
authors.initials: SH
authors.lastname: Jathar
authors.affiliation: Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA 15213; and.
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Gordon
authors.affiliation: Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA 15213; and.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Hennigan
authors.affiliation: National Exposure Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC 27711.
authors.forename: Havala O T
authors.initials: HO
authors.lastname: Pye
authors.affiliation: National Exposure Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC 27711.
authors.forename: George
authors.initials: G
authors.lastname: Pouliot
authors.affiliation: Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA 15213; and.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Adams
authors.affiliation: Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA 15213; and.
authors.forename: Neil M
authors.initials: NM
authors.lastname: Donahue
authors.affiliation: Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA 15213; and alr@andrew.cmu.edu.
authors.forename: Allen L
authors.initials: AL
authors.lastname: Robinson
mesh_terms: D000336:Aerosols / Q000032:analysis*; D000393:Air Pollutants / Q000032:analysis*; D001272:Atmosphere / Q000737:chemistry; D008697:Methane / Q000032:analysis; D009930:Organic Chemicals / Q000032:analysis*; D012905:Smog / Q000032:analysis; D014481:United States; D001335:Vehicle Emissions / Q000032:analysis
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D009930:Organic Chemicals; D012905:Smog; D001335:Vehicle Emissions; D008697:Methane
keywords: air quality; emissions inventory; particulate matter; photochemical oxidation; volatile organic compounds