Pollutant constituents of exhaust emitted from light-duty diesel vehicles

Light-duty diesel exhaust particulate matter and its constituents, including elemental carbon, organic carbon, water-soluble ionic species, elements, and polyaromatic hydrocarbons (PAHs), were measured by a dynamometer study and following the driving pattern of federal test procedure-75 (FTP-75). Fuel consumption of these light-duty diesel vehicles (LDDV) was in the range of 0.106–0.132 l km−1, and the average emission factors of NMHC (non-methane hydrocarbon), CO and NOx for light-duty vehicles were 0.158 (92% of total hydrocarbon), 1.395, and 1.735 g km−1, respectively. The particulate emission factor of LDDVs was 0.172 g km−1, and PM2.5 contributed to 88% of particulate mass. Al, S, Ca, and Fe emission factors were about 0.83–1.24 mg km−1 for PM2.5, and the particulate mass fractions of these elements ranged from 66 to 90% in PM2.5. Nitrate, sulfate, ammonium and nitrite were the major ionic species in diesel PM, and their emission factor ranged from 0.22 to 0.82 mg km−1 for PM2.5. The emission factor of total PAHs was 3.62 mg km−1 in this study, with about 40% in the gas phase and 60% in the particulate phase. Acenaphylene, naphthalene, fluoranthene, pyrene, and anthracene were the dominant PAHs, and their emission factors were more than 0.19 mg km−1. The content of nitro-PAHs was low, with most less than 0.040 mg km−1.