US EPA

3540829 

Journal Article 

Review 

Review of urban secondary organic aerosol formation from gasoline and diesel motor vehicle emissions 

Gentner, DR; Jathar, SH; Gordon, TD; Bahreini, R; Day, DA; El Haddad, I; Hayes, PL; Pieber, SM; Platt, SM; de Gouw, J; Goldstein, AH; Harley, RA; Jimenez, JL; Prévôt, AS; Robinson, AL 

2017 

1 

Environmental Science & Technology
ISSN: 0013-936X
EISSN: 1520-5851 

American Chemical Society 

WASHINGTON 

51 

3 

1074-1093 

English 

28000440 

10.1021/acs.est.6b04509 

WOS:000393738700012 

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. 

Aerosols; Emission control; Gases; Internal combustion engines; Organic compounds; Vehicles; Atmospheric oxidation; Catalyzed diesel particulate filters; Comprehensive evaluation; Conflicting evidence; Diesel motor vehicle; Exhaust aftertreatment; International perspective; Secondary organic aerosols; Gasoline; diesel fuel; gasoline; organic compound; ozone; aerosol; air pollutant; exhaust gas; aerosol formation; atmospheric modeling; emission control; fossil fuel; heterogeneity; literature review; oxidation; particulate matter; traffic emission; urban atmosphere; air pollution control; air quality; atmosphere; biofuel production; biotechnology; carbon footprint; catalyst; chemical composition; combustion; dynamics; environmental impact; environmental policy; Europe; evaluation study; exhaust gas; measurement; motor vehicle; oxidation; particulate matter; photochemistry; Review; secondary organic aerosol; traffic; uncertainty; United States; urban area; aerosol; air pollutant; exhaust gas; motor vehicle; Aerosols; Air Pollutants; Gasoline; Motor Vehicles; Organic Chemicals; Vehicle Emissions