Long-Term Trends in Mobile Source Emissions and Urban Air Quality

Brian McDonald (1)(2), Si-Wan Kim (1)(2), Gregory Frost (2), Stuart McKeen (1)(2), Robert Harley (3), and Michael Trainer (2).

Abstract
Mobile sources are a major urban emitter of carbon dioxide (CO2), and other co-emitted species including carbon monoxide (CO), nitrogen oxides (NOx), black carbon (BC), and volatile organic compounds (VOCs). We present long-term changes in mobile source emissions and corresponding changes in U.S. urban air quality, with an emphasis on precursors to ozone (O3) and organic aerosol (OA) formation.