Comparison of atmospheric polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons in an industrialized city (Kitakyushu) and two commercial cities (Sapporo and Tokyo)

Abstract

Airborne particulates were collected at a site near a group of factories in Kitakyushu, one of the most industrialized cities in Japan, and at downtown sites in Sapporo and Tokyo, typical large commercial cities. We determined the levels of polycyclic aromatic hydrocarbons (PAHs) and nitropolycyclic aromatic hydrocarbons (NPAHs), which are known to be carcinogenic and/or mutagenic. The atmospheric concentrations of most PAHs with 4-, 5-, and 6-rings were higher in Kitakyushu and Tokyo than in Sapporo. On the other hand, atmospheric concentrations of the strongly mutagenic NPAHs were the highest in Sapporo, intermediate in Tokyo, and lowest in Kitakyushu. The atmospheric concentrations of 1-nitropyrene (1-NP) in Kitakyushu were one order of magnitude lower than those in the two commercial cities. Therefore the concentration ratios of NPAHs to their nucleus PAHs were significantly smaller in Kitakyushu than in the two commercial cities. This result suggested that the atmospheric levels of NPAHs in Kitakyushu were comparatively low, although the air in Kitakyushu was as heavily polluted with PAHs as the air in Tokyo. The concentration ratio of dinitropyrenes (DNPs) to 1-NP in Kitakyushu was much higher than that in the other two cities. A possible reason for the above two differences between the two types of cities is the contribution of chimney exhaust of steel manufacturing plants in Kitakyushu, which contains high concentrations of PAHs.