Evaluation of Car Air Filters' Efficiency as Active Samplers for Polycyclic Aromatic Hydrocarbons and Heavy Metals

In this study, an innovative and inexpensive approach, based on car engine air filters (CAFs), was used to monitor polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs). CAFs were collected from two taxi garages in Guangzhou and analyzed for PAHs and heavy metals. The total concentrations of eight high molecular weight PAHs (Sigma PAHs) ranged from 923 to 11378 mu g/CAF. The average Sigma(PAHs) concentration in winter was slightly higher than in summer, a seasonal signal that is observed in most studies. The most abundant individual PAH was chrysene, followed by benzo[a] anthracene, benzo[b]fluoranthene and benzo[k]fluoranthene. Concentrations of benzo[a] pyrene (BaP) varied between 8.22 and 632 mu g/CAF. Based on estimated air volumes that pass through each CAF, atmospheric PAHs and heavy metals were estimated. Sigma(PAHs) ranged from similar to 20 to similar to 200 ng/m(3) for the average air volume estimate, being comparable to those reported previously using a high volume air sampler. BaP-equivalent carcinogenic potency were between 1 and 15.0 ng/m(3) (again, for the average scenario). The average concentrations of heavy metals in CAFs decreased in order of Zn > Cu > Pb > Cd.