Diurnal and nocturnal measurements of PAH, nitro-PAH, and oxy-PAH compounds in atmospheric particulate matter of a sugar cane burning region

A correlation matrix was used to explore the origins of the different compounds. The data suggested that during the daytime, direct emissions (mainly in vehicle exhaust) contributed to the presence of PAHs, nitro-PAHs, and oxy-PAHs in air. Photochemical production also appeared to be a source of the majority of nitro-PAHs and oxy-PAHs, while photolysis could have contributed to removal of the nitro-PAHs during the daytime. At night, sugar cane burning emissions were the primary source of the PAHs and nitro-PAHs, with additional sources also contributing to the levels of oxy-PAHs in the atmosphere.