Characterization, risk assessment, and source estimation of PM-bound polycyclic aromatic hydrocarbons during wintertime in the ambient air of Basrah City, Iraq.

In this study, the concentration and structure of polycyclic aromatic hydrocarbons (PAHs) associated with the ambient PM in Basrah City, Iraq have been investigated for the first time. From December 2021 to February 2022, PM samples were collected on quartz fiber filters, extracted using an optimized extraction protocol, and analyzed for the sixteen US EPA priority PAHs. The results indicated that 4- and 5-ring PAHs represent 52% of the total detected PAHs. The most abundant PAHs over the study period were chrysene (1.2 ± 1.5 ng m), fluorene (0.9 ± 1.4 ng m), and benzo[b]fluoranthene (0.7 ± 0.9 ng m). Source identification suggested that PM-bound PAHs primarily originated from pyrogenic and petrogenic activities in Basrah City. In addition, the cancer risk associated to PAH exposure was assessed based on benzo[a]pyrene equivalent concentration and was found ranging from 0.07 to 6.32 ng m; hence, it exceeded the threshold limit of 1.0 ng m established by the European legislation (EU, 2014). Benzo[a]pyrene was determined to be main contributor to total carcinogenic power of the detected PAHs, accounting for 50.3%, followed by dibenz[a,h]anthracene (22.3%). Similarly, benzo[a]pyrene represented a major contributor to PAH associated mutagenicity, accounting for 43.5% of the total.