Population density, particulate emission characterization, and impact on the particulate inventory of smoking vehicles in the South Coast Air Quality Management District

The impact of high-particulate-emission vehicles on the total light-duty vehicle particulate emission inventory in the South Coast Air Quality Management District (SCAQMD) has been estimated by an analysis of the SCAQMD's CUT-SMOG database, a field survey of smoking vehicles, and particulate emissions testing of representative smoking vehicles. The field study, carried out at 61 sites throughout the SCAQMD, showed that 1.11%-1.75% of the vehicles in the light-duty fleet emit visible smoke. This fleet of smoking vehicles is composed mainly of older vehicles, 8 to 18 years of age. Particulate emission testing of 23 smoking vehicles gave an average Federal Test Procedure (FTP) weighted emission rate of 399 mg/mi with a range of 64-2,323 mg/mi, while the average IM240 emission rate was 346 mg/mi, with a range from 13-1,807 mg/mi. The contribution of light-duty smoking vehicles to the particulate emissions inventory in the SCAQMD is estimated to be 0.51-0.81 tons per day.