Diurnal Concentrations of 1, 3-, 1, 6-, 1, 8-Dinitropyrenes, 1-Nitropyrene and Benzo [a] pyrene in Air in Downtown Kanazawa and the Contribution of Diesel-Engine Vehicles

Direct-acting mutagenic 1, 3-dinitropyrene (1, 3-DNP), 1, 6-DNP, 1, 8-DNP and 1-nitropyrene (1-NP) and indirect-acting mutagenic benzo [a] pyrene (BaP) in airborne particulates collected by the side of a busy intersection in downtown Kanazawa were determined by high-performance liquid chromatography (HPLC) with chemiluminescence and fluorescence detection. Time courses of their concentrations were high in the morning (8 : 00-10 : 00) and evening (16 : 00-20 : 00) and low from the midnight until early morning (0 : 00-6 : 00). Levels of each DNP (in the range of fmol/m3) and 1-NP (in the range of sub pmol/m3) were, respectively, more than three and about one order of magnitude lower than that of BaP. Large correlation coefficients (0.85-0.91) between their concentrations, traffic volume, and carbon monoxide and nitrogen monoxide concentrations suggested that the main source was vehicles. Utilizing the concentration ratios, ([1, 3-DNP]+[1, 6-DNP]+[1, 8-DNP])/[1-NP], in airborne particulates (0.014), gasoline particulates (0.56) and diesel particulates (0.013), contributions (%) of dieselengine vehicles to the three DNPs and 1-NP in the air were estimated to be 94.3% and 99.8%, respectively.