Assessment of potentially toxic elements pollution intensity in indoor dust of Tehran Greater City

Population growth and increasing urbanization expose city dwellers to higher degrees of urban pollutants, especially when they spend long time in enclosed environments with inadequate ventilation. This study is the first research on inorganic pollutants in indoor dust particles of Tehran city, which applies geochemical indices to estimate the intensity of dust pollution by potentially harmful elements. A number of 31 indoor dust samples were passively collected from inside the residential and office buildings in the central and densely populated districts of the city and were analyzed by ICP-Ms at the Universitat Rovira i Virgili, Tarragona, Spain. Single geochemical indices of the Contamination Factor, Geoaccumulation Index, Enrichment Factor, and cumulative indices of Pollution Load and Potential Ecological Risk Indices were calculated. The results of elemental analysis showed that the concentration of arsenic, cadmium, copper, mercury, lead and zinc in Tehran indoor dust is higher than that in some cities in the world. On the other hand, cobalt, chromium, nickel and vanadium present low concentrations in the analyzed indoor dust samples. This result was confirmed by the cumulative indices as well as the contamination factor. In contrast, some other factors showed a low to medium degree of pollution for the above-mentioned elements. Based on the obtained concentration of elements in the dust samples, it can be argued that the geochemical indices indicating low to moderate pollution are not applicable and trustable in the current study.