Spatiotemporal Distribution of PM10 and PM2.5 within and Around The City of Arak, Iran: Effect of Natural Sources

In the present study, the concentrations of PM10 and PM2.5 were measured within and around the city of Arak from March 2016 through March 2017. The measurements were done every 12 days by means of TSI DustTrak sampler containing specific heads for PM10 and PM2.5. The sampling points included eight stations within the city as well as two stations around the city. The average (±SD) values of 108.56 ±55.56 and 42.58 ±15.88µg/m3 were obtained for daily concentrations of PM10 and PM2.5, respectively. PM10 showed the maximum concentrations during summer (144.47µg/m3 ) followed by spring (109.44 µg/m3 ), autumn (100.92µg/m3 ), and winter (77.12µg/m3 ). On the other hand, the highest values of PM2.5 was observed during winter (44.13 µg/m3 ) followed by autumn (42.74µg/m3 ), summer (37.58µg/m3 ) and spring (33.77 µg/m3 ). The correlation between PM10 and PM2.5 was highest in winter (R2=0.9288) followed by spring (R2=0.6728), summer (R2=0.6713), and autumn (R2=0.5592). It was concluded that more than 57 and 19% of the PM2.5 and PM10 samples exceeded the Iranian national ambient air quality standards, respectively.