title: Review of Urban Secondary Organic Aerosol Formation from Gasoline and Diesel Motor Vehicle Emissions.
abstract: Secondary organic aerosol (SOA) is formed from the atmospheric oxidation of gas-phase organic compounds leading to the formation of particle mass. Gasoline- and diesel-powered motor vehicles, both on/off-road, are important sources of SOA precursors. They emit complex mixtures of gas-phase organic compounds that vary in volatility and molecular structure-factors that influence their contributions to urban SOA. However, the relative importance of each vehicle type with respect to SOA formation remains unclear due to conflicting evidence from recent laboratory, field, and modeling studies. Both are likely important, with evolving contributions that vary with location and over short time scales. This review summarizes evidence, research needs, and discrepancies between top-down and bottom-up approaches used to estimate SOA from motor vehicles, focusing on inconsistencies between molecular-level understanding and regional observations. The effect of emission controls (e.g., exhaust aftertreatment technologies, fuel formulation) on SOA precursor emissions needs comprehensive evaluation, especially with international perspective given heterogeneity in regulations and technology penetration. Novel studies are needed to identify and quantify "missing" emissions that appear to contribute substantially to SOA production, especially in gasoline vehicles with the most advanced aftertreatment. Initial evidence suggests catalyzed diesel particulate filters greatly reduce emissions of SOA precursors along with primary aerosol.
authors.affiliation: Department of Chemical & Environmental Engineering, Yale University , New Haven, Connecticut 06511, United States.|School of Forestry & Environmental Science, Yale University , New Haven, Connecticut 06511, United States.
authors.forename: Drew R
authors.identifier: 0000-0003-3066-2614
authors.initials: DR
authors.lastname: Gentner
authors.affiliation: Department of Mechanical Engineering, Colorado State University , Fort Collins, Colorado 80523, United States.
authors.forename: Shantanu H
authors.identifier: 0000-0003-4106-2358
authors.initials: SH
authors.lastname: Jathar
authors.affiliation: Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder, Colorado 80309, United States.|NOAA Earth System Research Laboratory , Boulder, Colorado 80305, United States.
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Gordon
authors.affiliation: Department of Environmental Sciences, University of California , Riverside, California 92521, United States.
authors.forename: Roya
authors.initials: R
authors.lastname: Bahreini
authors.affiliation: Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder, Colorado 80309, United States.|Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309, United States.
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Day
authors.affiliation: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute , Villigen, Switzerland.
authors.forename: Imad
authors.initials: I
authors.lastname: El Haddad
authors.affiliation: Department of Chemistry, Université de Montréal , Montréal, QC, Canada.
authors.forename: Patrick L
authors.initials: PL
authors.lastname: Hayes
authors.affiliation: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute , Villigen, Switzerland.
authors.forename: Simone M
authors.initials: SM
authors.lastname: Pieber
authors.affiliation: Department of Atmosphere and Climate, Norwegian Institute for Air Research , 2007 Kjeller, Norway.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Platt
authors.affiliation: Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder, Colorado 80309, United States.|NOAA Earth System Research Laboratory , Boulder, Colorado 80305, United States.
authors.forename: Joost
authors.initials: J
authors.lastname: de Gouw
authors.affiliation: Department of Environmental Science, Policy and Management, University of California , Berkeley, California 94720, United States.|Department of Civil and Environmental Engineering, University of California , Berkeley, California 94720, United States.
authors.forename: Allen H
authors.initials: AH
authors.lastname: Goldstein
authors.affiliation: Department of Civil and Environmental Engineering, University of California , Berkeley, California 94720, United States.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Harley
authors.affiliation: Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder, Colorado 80309, United States.|Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309, United States.
authors.forename: Jose L
authors.identifier: 0000-0001-6203-1847
authors.initials: JL
authors.lastname: Jimenez
authors.affiliation: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute , Villigen, Switzerland.
authors.forename: André S H
authors.initials: AS
authors.lastname: Prévôt
authors.affiliation: Department of Mechanical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Allen L
authors.initials: AL
authors.lastname: Robinson
mesh_terms: D000336:Aerosols; D000393:Air Pollutants; D005742:Gasoline; D018986:Motor Vehicles; D009930:Organic Chemicals; D001335:Vehicle Emissions
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D005742:Gasoline; D009930:Organic Chemicals; D001335:Vehicle Emissions