The effect of nitrogen dioxide and ozone on the decomposition of particle-associated polycyclic aromatic hydrocarbons during sampling from the atmosphere

Abstract

The effects of NO 2 and O 3 exposure on the degradation of polycyclic aromatic hydrocarbons (PAH) during high-volume sampling of airborne particulate matter were studied. Addition of 1 ppm NO 2 during ambient air sampling caused degradation of pyrene, benz(a)anthracene and benzo(a)pyrene, most probably due to nitration. Acid particles seem to enhance the reaction. The results indicate that NO 2 concentrations within the range normally formed in urban air may cause degradation of some reactive PAH. Addition of 200 ppb O 3 caused degradation in one of the three experiments only.