Concentrations, trends and vehicle source profile of polynuclear aromatic hydrocarbons in the U.K. atmosphere

Intensive seasonal sampling campaigns were undertaken at an urban site in the West Midlands conurbation and simultaneously at a nearby rural location with hi-vol and medium volume samplers modified in order to collect particulate and vapour phase polycyclic aromatic hydrocarbons (PAHs) by means of filters and polyurethane foam plugs (PUFs). Eighteen PAH species were determined by means of Soxhlet extraction followed by clean-up and reversed-phase HPLC with in-series UV-visible and fluorescence detectors. PAH at the urban site were found to be present in greater concentrations than at the rural site by a factor of approximately four, and concentrations in the winter campaign exceeded those in the summer by a factor of five. Gas-particle partitioning characteristics of the various PAH in air were investigated and found consistent with Yamasakiʹs equation. Present data suggest that PAH concentrations have decreased in the U.K., probably quite dramatically, over the past 15 years. A sampling study carried out in the Queensway road tunnel in central Birmingham, revealed concentrations of PAHs and total suspended particulates (TSP) approximately one order of magnitude greater than levels found in ambient air samples from the urban location during winter.