Heavy metals and their source identification in particulate matter (PM_2.5) in Isfahan City, Iran

The presence of heavy metals (HMs) in particulate matters (PMs) particularly fine particles such as PM_2.5 poses potential risk to the health of human being. The purpose of this study was to analyze the contents of HMs in PM_2.5 in the atmospheric monitoring stations in Isfahan city, Iran, in different seasons between March 2014 and March 2015 and their source identification using principle component analysis (PCA). The samples of PM_2.5 were taken using a high volume sampler in 7 monitoring stations located throughout the city and industrial zones since March 2014 to March 2015. The HMs content of the samples was measured using ICP-MS. The results showed that the concentrations of As, Cd and Ni were in a range of 23-36, 1-12, and 5-76ng/m³ at all the stations which exceeded the US-EPA standards. Furthermore, the concentrations of Cr and Cu reached to 153 and 167ng/m³ in some stations which were also higher than the standard levels. Depending on the potential sources of HMs, their concentration in PM_2.5 through the various seasons was different. PCA illustrated that the different potential sources of HMs in the atmosphere, showing that the most important sources of HMs originated from fossil fuel combustion, abrasion of vehicle tires, industrial activities (e.g., iron and steel industries) and dust storms. Management and control of air pollution of industrial plants and vehicles are suggested for decreasing the risk of the HMs in the region.