Chemical characterization and toxicity assessment of fine particulate matters emitted from the combustion of petrol and diesel fuels.

Fuel consumption is one of the major contributors to air pollution worldwide. Plenty of studies have demonstrated that the diesel and petrol exhaust fine particulate matters (FPMs) are associated with increases of various diseases. However, the influences of different fuel types and their chemical components on toxicity have been less investigated. In this study, four kinds of fuels that widely used in China were burned in a laboratory simulation, and the FPMs were collected and analyzed. Transmission electron microscopy showed that black carbon was mainly soot with a dendritic morphology. For light diesel oil, marine heavy diesel oil, 93 octane petrol and 97 octane petrol diesel oil, the emission factors of FPMs were 3.05±0.29, 3.21±0.54, 2.36±0.33, and 2.28±0.25g/kg fuel, respectively. And the emission factors for the "16 US EPA" PAHs of FPM were 0.45±0.20, 0.80±0.22, 1.00±0.20, and 1.05±0.19mg/g FPMs, respectively. Fe is the most abundant metal in these FPMs, and the emission factors of FPMs were 2.58±1.70, 4.45±0.11, 8.18±0.58, and 9.24±0.17mg/g FPMs, respectively. We ranked the cytotoxicity of the FPMs emission from fuels combustion: marine heavy diesel oil>97 octane petrol>93 octane petrol>light diesel oil, and the genotoxicity of FPMs emission from fuels combustion: marine heavy diesel oil>light diesel oil>93 octane petrol>97 octane petrol. Significant correlations were found between PAH concentrations and reactive oxygen species (ROS) generation. Our results demonstrated that fuels exhaust FPMs have strong association with ROS activity, cytotoxicity and genotoxicity. These results indicated that fuels exhaust FPMs pose a potentially serious health, and emphasized the importance of assessing the health risks posed by the particulate pollutants in vehicle exhausts.