Investigating PM(2.5) toxicity in highly polluted urban and industrial areas in the Middle East: human health risk assessment and spatial distribution 

Exposure to particulate matter (PM) can be considered as a factor affecting human health. The aim of this study was to investigate the concentration of PM(2.5) and heavy metals and their influence on survival of A549 human lung cells in exposure to PM(2.5) breathing air of Ahvaz city. In order to assess the levels of PM(2.5) and heavy metals, air samples were collected from 14 sampling stations positioned across Ahvaz city during both winter and summer seasons. The concentration of heavy metals was determined using ICP OES. Next, the MTT assay [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] was employed to ascertain the survival rate of A549 cells. The findings from this research demonstrated that average PM(2.5) of the study period was (149.5 μg/m(3)). Also, the average concentration of PM(2.5) in the urban area in winter and summer was (153.3- and 106.9 μg/m(3)) and in the industrial area this parameter was (191.6 and 158.3 μg/m(3)). The average concentration of metals (ng/m(3)) of urban areas against industrial, Al (493 vs. 485), Fe (536 vs. 612), Cu (198 vs. 212), Ni (128 vs. 129), Cr (48.5 vs. 54), Cd (118 vs. 124), Mn (120 vs. 119), As (51 vs. 67), Hg (37 vs. 50), Zn (302 vs. 332) and Pb (266 vs. 351) were obtained. The results of the MTT assay showed that the highest percentage of cell survival according to the exposure concentration was 25 > 50 > 100 > 200. Also, the lowest percentage of survival (58.8%) was observed in the winter season and in industrial areas with a concentration of 200 μg/ml. The carcinogenic risk assessment of heavy metals indicated that except for Cr, whose carcinogenicity was 1.32E−03, other metals were in the safe range (10(–4)–10(–6)) for human health. The high concentration of PM(2.5) and heavy metals can increase respiratory and cardiovascular diseases and reduce the public health level of Ahvaz citizens.