Concentration Level and Health Risk Assessment of Heavy Metals in PM2.5 in Ambient Air of Makkah City, Saudi Arabia.

Exposure to air pollution in general and Particulate Matter (PM) and its constituents, in particular, can be extremely harmful to human health. Given the importance of PM and its constituents concerning human health, this study aimed to evaluate the levels of PM2.5 and some HMs in the atmosphere of Makkah City, Saudi Arabia, and assess the health risks associated with exposure to HMs. The 24-h mean concentration of PM2.5 in Makkah city was 38.0±13.5 µg/m3 which exceeded the WHO air quality guidelines and national ambient air quality standard of Saudi Arabia. The average concentrations of HMs were Mn (54.3±13.3 ng/m3)>Pb (40.3±9.2 ng/m3)>As (27.8±4.1 ng/m3)>Ni (20.5±12.9 ng/m3)> Cr (18.2±6.2 ng/m3)>Cd (13.0±3.1 ng/m3). The non-carcinogenic risks (non-CRs) and carcinogenic risks (CRs) associated with exposure to measured HMs were analyzed using hazard quotient (HQ) and incremental lifetime cancer risk (ILCR), respectively. Arsenic was found to be the major contributor to health risk and oral ingestion was found to be the most detrimental pathway of exposure to HMs. For future research, it is recommended to evaluate the HMs and their health risks in various environmental media in different Saudi cities. [ABSTRACT FROM AUTHOR]