Benzo[b]fluoranthene, a potential alternative to benzo[a]pyrene as an indicator of exposure to airborne PAHs in the vicinity of Soderberg aluminum smelters

Benzo[b]fluoranthene (B[b]F) was used in relative abundance ratios (RARs), a parameter obtained by dividing the concentration of individual polycyclic aromatic hydrocarbons (PAHs) found in a given sample by the concentration of B[b]F in the same sample. The B[b]F RARs were derived for PAH concentrat ions measured at stacks and sampling stations in the vicinity of two Soderb erg aluminum horizontal stud smelters (HSSs). The samples collected were an alyzed by high-performance liquid chromatography using UV and fluorescence detection. A total of 15 PAHs were analyzed, but, due to the inefficiency o f the sampling method used in collecting gaseous PAHs, only particulate PAH s were considered. Comparisons between the B[b]F RARs obtained simultaneous ly at the source (stack) and those obtained at sampling stations at the two smelters showed that B[b]F degrades more slowly than or at the same rate a s most other particulate PAHs monitored. Twenty-three months of urban sampl ing in the vicinity of one of the aluminum HSSs are also presented, and the results indicate that B[b]F is more stable than all other particulate PAHs investigated. Sampling conducted during a smelter shutdown period confirme d that B[b]F was a much better marker of this source than was benzo[a]pyren e (B[a]P), the usual indicator. The remarkable stability of the benzo[k] fl uoranthene (B[k]F)/B[b]F ratio is also discussed.