Two reasons could explain this clear difference. First, our sampling
sites were all located close to a petrochemical complex, which is one
of the most important ambient pollution sources of PAHs and releases
mainly two- and three-ring PAHs compounds. Therefore, both the
PAH concentrations and the contributions of LMW PAHs in the studied
samples were higher than those reported in other studies. Second, unlike
other studies, our study employed XAD-2 in air sampling. Hence,
the effect of collecting LMW PAHs was better than the effects reported