PM2.5 and associated polycyclic aromatic hydrocarbon and mutagenicity emissions from motorcycles.

In this study, PM(2.5) in diluted exhausts of motorcycles are collected and emission characteristics of PM(2.5)-associated polycyclic aromatic hydrocarbons (PAHs) and mutagenicities are investigated. The measured mutagenicity emission factors with metabolic activation for new fuel injection, used fuel injection, new carburetor and used carburetor motorcycles are 7.77 x 10(4), 1.18 x 10(5), 1.32 x 10(5) and 1.15 x 10(5) rev/km, respectively. The mutagenicity emission factors with metabolic activation are higher than the corresponding values without metabolic activation. The average PAH emission factors are 12.3, 16.3, 25.5 and 26.5 microg/km for new and used fuel-injection motorcycles, and new and used carburetor-operated motorcycles, respectively. The correlation coefficients between PAHs and mutagenicity emission factors are higher with metabolic activation (0.59) than that without metabolic activation (0.31).