Studies on Behavior and Reduction of Unregulated Air Pollutant : Nitroarenes

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(1) We introduced another separation column (ODS), a zinc reducer column and a switching valve into the nitroarene analyzer, a HPLC equipped with a chemiluminescence detector, to determine trace levels of nitroarenes.(2) Benzene-ethanol extracts from diesel exhaust particulates were separated into 5 fractions on a silica-gel column with mixtures of n-hexane, dichloromethane and methanol. The strong direct-acting mutagenicities were observed in the dichloromethane-methanol and methanol fractions in the Ames test using the S.typhimurium YG1024 strain and nitroarenes were mainly in the former fraction of the two. The mutagenic contribution of nitroarenes were 1/3 of the all fractions. The large contribution of nitroarenes to the mutagenicity of urban air suggests that the monitoring of nitroarenes is very important for assessing the risk of air pollutants.(3) Concentrations of 1,3-, 1,6- and 1,8-dinitropyrenes (DNPs) and 1-nitropyrene (NP) in urban air were in the following decreasing order, Sapporo>Tokyo>Kanazawa. However, the concentrations in downtown areas of the three cities were at similar levels. The relative concentration of DNPs to that of 1-NP was the highest in Sapporo. As a reason, the large ration of diesel-engine vehicles was considered. Their concentrations showed diurnal and seasonal variations.(4) The relative concentrations of DNPs and 1-NP to polycyclic aromatic hydrocarbons were lower in the suburban areas than in the downtown areas, suggesting that DNPs and 1-NP degradated in the presence of sun light during the transportation. On the other hand, the fact that both 2-nitrofluoranthene (NF) and 2-NP were not detected in diesel exhaust particulates but detected in airborne particulates suggested that these two compounds were formed in air.