Risk Assessment and Source Apportionment of Metals on Atmospheric Particulate Matter in a Suburban Background Area of Gran Canaria (Spain)

Concentration levels of 11 heavy metals were analyzed in PM [Formula: see text] and PM [Formula: see text] samples from a suburban area frequently affected by Saharan dust in which is located a school. The heavy metals risk assessment was carried out by the 2011 U.S. Environmental Protection Agency method, estimating the chronic and carcinogenic hazard levels both in adults and children. The highest level of chronic hazard was reached for Cr, with values of approximately 8 (PM [Formula: see text] , adulthood), 2 (PM [Formula: see text] , childhood) and 1.5 (PM [Formula: see text] , adult age), significantly exceeding the limit value (equal to 1). Regarding the carcinogenic risk level, it was also high for Cr, with values between 10 [Formula: see text] and 10 [Formula: see text] for both study populations and particle size. For the rest of the studied metals, no health risk levels of concern were obtained. The positive matrix factorization method was used for the estimation of heavy metal emission sources apportionment. Non-exhaust vehicle emissions were the main source of Cr emissions under PM [Formula: see text] , while industrial processes were the main source for PM [Formula: see text]. Mineral dust and marine aerosol were common emission sources for both particles sizes—with different contributions. Vehicle emissions, construction and agricultural activities were the main emission sources for PM [Formula: see text] , and fossil fuel combustion, road dust re-suspension and ammonium sulfate were for PM [Formula: see text]. The results obtained in this study support the need to continue applying mitigation measures in suburban areas which are affected by nearby anthropogenic emissions, causing the consequent emission of materials hazardous to human health.