This research investigates the mileage and the health risk assessment of aerosol carcinogenicity and mutagenicity emitted by ten in-use motorcycles. The total p-PAHs emission factor of ten in-use motorcycles are 676.3 mu g km(-1) with average of 67.6 +/- 13.6 mu g km(-1). Naphthalene (Nap) shows the largest emission factors, followed by phenanthrene (PA) and fluoranthen (FL). The mileage present high correlation coefficient (Rsp = 0.681) with CO. CO is associated with cumulative mileage leading to bad combustion efficiency, which caused low to high relationship for total p-PAHs (Rsp = 0.388), PM2.5 (Rsp = 0.680) and NOx (Rsp = 0.799). Both PM2.5 and total p-PAHs are generally generated via incomplete combustion and the results expressed the moderate to high correlation (Rsp = 0.578, 0.898) with NOx. Taking into consideration of high-mileage motorcycles (30,001-50,000 km), the toxic equivalent of carcinogenicity and mutagenicity exhaust are about 4.67, 1.99 and 3.89, 2.0 times higher than low (10,001-20,000 km) and middle (20,001-30,000 km) cumulative mileages, respectively. Therefore, in the conclusion of our study in compared with that of other research directed the fact that lower carcinogenicity and mutagenicity emission factor were found at lower cumulative mileages motorcycles however, the impact increases with the high cumulative mileage motorcycles.