Determination of atmospheric nitro-polycyclic aromatic hydrocarbons and their precursors at a heavy traffic roadside and at a residential area in osaka,japan

摘要

Concentrations of nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) and polycyclic aromatic hydrocarbons (PAHs) in airborne particles collected at two sites,a residential area and a roadside with high traffic density in Osaka,Japan,in summer and winter were quantified.Five nitro-PAHs,1-nitropyrene (1-NP),2-nitropyrene (2-NP),2-nitrofluoranthene (2-NF),3-nitrofluoranthene (3-NF),and 2-nitrotriphenylene (2-NTP) and five PAHs,pyrene (Py),fluoranthene (Fl),triphenylene (Tp),benzo[k]fluoranthene (B(k)F),and benzo[a]pyrene (B(a)P) were determined by high-performance liquid chromatography with chemiluminescence and fluorescence detection.At both sites,the mean concentration of 1-NP was higher in winter than in summer.On the contrary,the mean concentrations of 2-NF and 2-NP were higher in summer than in winter.Observed 2-NF/2-NP ratio in the range from 0.40 to 16 suggests that 2-NF and 2-NP were dominantly formed via OH radical initiated reaction in the atmosphere.Nitro-PAH and PAH concentrations were generally higher at a roadside area than at a residential area due to extremely higher concentration of particles at a roadside area.l-NP/B(k)F ratio was higher at a roadside area than at a residential area,while 2-NF/B(k)F,2-NP/B(k)F,and 2-NTP/B(k)F ratios were higher at a residential area than at a roadside area.The diurnal changes of2-NF/B(k)F,2-NP/B(k)F,and 2-NTP/B(k)F ratios were slightly different from those of 1-NP/B(k)F and 3-NF/B(k)F ratios.Thus,the differences in the patterns of nitro-PAHs/B(k)F ratios may be due to the disparity in formation pathways of each nitro-PAH.