Abstract
Selected polycyclic aromatic hydrocarbons (PAH), nitrated PAH, and quinoid PAH (PAH-quinone) in airborne particles were simultaneously determined at Beijing, China, Osaka, Japan, and Wajima, Japan. The concentration of particle-associated 1,2-benzanthraquinone (benz[a]anthracene-7,12-dione; BAQ), a quinoid PAH, at Beijing was higher than that at Osaka and Wajima by factors of 35 and 200, respectively. Strong correlations between the BAQ and 2-nitropyrene concentrations in the summer and between the BAQ and 1-nitropyrene concentrations in the winter imply that atmospheric secondary reactions and primary emissions significantly contribute to the occurrence of atmospheric BAQ in the summer and winter, respectively. The concentration ratios of BAQ to benz[k]fluoranthene (BkF) in the summer were lower than those in the winter due to the instability of BAQ under sunlight. The BAQ/BkF ratio at Beijing in the Asian dust season was significantly higher than that in the regular spring season, suggesting that the secondary formation of BAQ is promoted by catalytic effects on the Asian dust surface.
