Characteristics and health risk assessment of heavy metal contamination from dust collected on household HVAC air filters

Abstract

Heavy metals associated with airborne particulate matter are detrimental to human health, but risk assessment is difficult due to the technical challenges of determining exposure rates. In houses and other buildings, the heating, ventilation and air conditioning (HVAC) system is equipped with an air filter that captures airborne particulate matter from the indoor air that enters the HVAC system. This study used the air filter dust as a proxy for the heavy metal exposure of children and adults, based on a household study in Kuwait. Air filter dust contained from 12.5 ± 5 mg Co/kg dust to 14 453 ± 5046 mg Fe/kg dust. Houses had high levels of Fe, Al, Zn, and Mn and relatively low concentrations of As and Co. Source apportionment revealed that metals in air filter dust were from natural and anthropogenic sources, including vehicular emissions, fossil fuel combustion, and metals-related industries. The total Hazard Index (HI; Σ exposure routes) for heavy metals was >1 for children and adults. Total cancer risks (TCR; Σ exposure routes) were 5.93 × 10−3 (95% CI: 5.28 × 10−3– 6.59 × 10−3) for children and 5.16 × 10−3 (95% CI: 4.59 × 10−3 – 5.73 × 10−3) for adults. Heavy metals, particularly the Cr and Pb concentrations, contribute to the non-carcinogenic and carcinogenic health risks of children and adults in Kuwait households.