natural airborne dust and heavy metals: a case study for kermanshah, western iran (2005-2011).

dust pollution has become a serious environmental problem especially in recent decades. the present study aim was the investigation of the levels of pm10 concentration in kermanshah, western iran and also measured five important heavy metals (pb, cd, as, hg and cr) in some samples during 2005 to 2011.a total 2277 samples were collected from air pollution measurement station belonging to the department of environment in kermanshah. furthermore, four samples were collected during dusty days to determine the selected heavy metals concentration. the samples were analyzed statistically using the spss ver.16.the highest seasonal average concentration in spring was recorded in 2008 with 216.63μg/m(3), and the maximum values of 267.79 and 249.09μg/m(3) were observed in summer and winter in 2009, respectively. the maximum concentration of 127.1μg/m(3) was in autumn in 2010. the metals concentration (pb, cd, as, hg and cr) of samples were 42.32±5.40, 37.45±9.29, 3.51±2.07, 1.88±1.64 and 0μg/g in july, 2009, respectively.according to national ambient air quality of usepa guidelines, the most days with non-standard, warning, emergency and critical conditions were related to 2009 (120 days) while the least polluted days were recorded in 2006 (16 days). there are concerns about the increasing frequency and intensity trend of dust storms in recent years as a result of special condition in neighboring western countries which it could endanger public health and environment. all measured heavy metals except mercury was higher than the standard level of who and usepa.