Use of benzo[a]pyrene relative abundance ratios to assess exposure to polycyclic aromatic hydrocarbons in the ambient atmosphere in the vicinity of aSoderberg aluminum smelter

The purpose of this study was to investigate the use of benzo[a]pyrene (B[a ]P) relative abundance ratios (RARs) to assess exposure to polycyclic aroma tic hydrocarbons (PAHs) in the urban atmospheric air in the vicinity of a h orizontal stud Soderberg aluminum reduction facility. The B[a]P RARs refer to the concentration of individual PAHs measured in a given sample divided by the concentration of B[a]P found in the same sample. This study compared the B[a]P RARs calculated for the facility stack and three sites near the Soderberg aluminum smelter for three different sampling periods. Interperio d differences were significant for many of the PAI-Is, and the differences between the stations proved insignificant at p < 0.05. The differences betw een each individual station and the facility stack were significant for all PAHs. B[a]P RARs increased in value at the stations compared with the stac k, indicating that B[a]P may be degraded or removed from the atmosphere at a rate greater than that of the majority of the measured PAHs. it is conclu ded that B[a]P and B[a]P RARs may be poor markers of exposure to PAHs in th e vicinity of this Soderberg aluminum refinery for the entire mixture of PA Hs present in the ambient atmosphere.