Measurements of nitro-PAH in the atmospheres of two cities

Analytical techniques have been developed based upon both HPLC with fluorescence detection of amino derivatives and upon GC/NICIMS for analysis of nitro-PAH in the atmosphere. Samples taken within a busy road tunnel, which should be representative of the emission source profile, indicated the expected presence of 9-nitroanthracene and 1-nitropyrene. Additionally, vapour-phase 1-nitronaphthalene and 2-nitronaphthalene were detected, and it is unclear whether these are directly emitted or formed from low activity free radical chemistry within the tunnel atmosphere, or a combination of the two. A comprehensive suite of nitro-PAH (1-nitronaphthalene, 2-nitronaphthalene, 9-nitroanthracene, 1-nitropyrene, 2-nitrofluoranthene and 7-nitrobenz[a]anthracene) have been determined in the city atmospheres of Birmingham, UK and Damascus, Syria. Whilst the nitronaphthalenes were detectable only in the vapour phase, 9-nitroanthracene was detectable in both particulate and vapour forms, and 1-nitropyrene, 2-nitrofluoranthene and 7-nitrobenz[a]anthracene were present solely in association with airborne particles. Concentrations measured in the winter months were highly comparable in the two cities despite differences in the motor vehicle parc and reflect the presence of both directly emitted compounds and compounds likely to have been formed within the atmosphere. Concentrations were broadly comparable with those measured at other urban sites across the world, although in most other studies a more limited suite of compounds was determined.