Characterization of PAHs and metals in indoor/outdoor PM<inf>10</inf>/PM<inf>2.5</inf>/PM<inf>1</inf> in a retirement home and a school dormitory

Abstract

In the present work, we investigated the characteristics of polycyclic aromatic hydrocarbons (PAHs) and metal(loid)s in indoor/outdoor PM<inf>10</inf>, PM<inf>2.5</inf>, and PM<inf>1</inf> in a retirement home and a school dormitory in Tehran from May 2012 to May 2013. The results indicated that the annual levels of indoor and outdoor PM<inf>10</inf> and PM<inf>2.5</inf> were much higher than the guidelines issued by the World Health Organization (WHO). The most abundant detected metal(loid)s in PM were Si, Fe, Zn, Al, and Pb. We found higher percentages of metal(loid)s in smaller size fractions of PM. Additionally, the results showed that the total PAHs (?PAHs) bound to PM were predominantly (83-88%) found in PM<inf>2.5</inf>, which can penetrate deep into the alveolar regions of the lungs. In general, carcinogenic PAHs accounted for 40-47% of the total PAHs concentrations; furthermore, the smaller the particle size, the higher the percentage of carcinogenic PAHs. The percentages of trace metal(loid)s and carcinogenic PAHs in PM<inf>2.5</inf> mass were almost twice as high as those in PM<inf>10</inf>. This can most likely be responsible for the fact that PM<inf>2.5</inf> can cause more adverse health effects than PM<inf>10</inf> can. The average BaP-equivalent carcinogenic (BaP-TEQ) levels both indoors and outdoors considerably exceeded the maximum permissible risk level of 1ng/m3 of BaP. The enrichment factors and diagnostic ratios indicated that combustion-related anthropogenic sources, such as gasoline- and diesel-fueled vehicles as well as natural gas combustion, were the major sources of PAHs and trace metal(loid)s bound to PM. é 2015 Elsevier B.V.