Comparison of Regulated and PM2.5 EC/OC Emissions from Light-Duty Gasoline, Diesel and CNG Vehicles over Different Driving Cycles 2008-01-1745

Understanding source contributions to ambient atmospheric particulate matter (PM) and toxic chemical pollution is critical to the development of effective mobile source emission control strategies. In this part of a larger PM source apportionment study, motor vehicle exhaust was characterized for eighteen light-duty vehicles driven over four driving cycles on a chassis dynamometer. Vehicle emission testing was conducted from July 2005 to May 2006 and included eleven gasoline vehicles, one gasoline-electric hybrid, two compressed natural gas (CNG) vehicles, and four diesel vehicles. Primary gaseous emissions of total hydrocarbons (THC), CO, NO_x, CO₂, as well as PM_2.5 (PM with aerodynamic diameter less than 2.5 microns), PM_2.5 elemental and organic carbon (EC/OC), polycyclic aromatic hydrocarbons (PAHs), and potential molecular markers, such as hopanes and steranes, were measured. Presented here are comparisons of regulated emissions, CO_2, and PM_2.5 EC/OC from gasoline, CNG, and diesel vehicles. Detailed molecular level analysis of PAHs and marker compounds will be presented elsewhere.