Levels, potential sources and human health risk of polycyclic aromatic hydrocarbons (PAHs) in particulate matter (PM10) in Kumasi, Ghana

Airborne particulate samples were collected on quartz filters to determine the concentrations, sources and health risks of polycyclic aromatic hydrocarbons (PAHs) in air in Kumasi, Ghana. A total of 32 air samples were collected in Kwame Nkrumah University of Science and Technology (KNUST) campus (pristine site) and city centre (CC). Samples were extracted with 1:2 v/v acetone:hexane mixture prior to GC-MS analyses. The sum of concentrations of 17 PAHs in air ranged from 0.51 to 16 (KNUST) and 19-38 ng/m3 (CC). The concentration of benzo[a]pyrene, BaP, ranged from below detection limit to 0.08 ng/m3 (KNUST) and 1.6 to 5.6 ng/m3 (CC). Chemical mass balance model showed that PAHs in air in Kumasi were mainly from fuel combustion. The total BaP equivalent concentration (BaPeq) in CC was 18 times higher compared to KNUST; based on the European Legislation and Swedish and UK Standards for BaP in air, CC could be classified as highly polluted. Estimated carcinogenicity of PAHs in terms of BaPeq indicated that BaP was the principal PAH contributor in CC (70 %). Health risk to adults and children associated with PAH inhalation was assessed by taking into account the lifetime average daily dose and corresponding incremental lifetime cancer risk (ILCR). The ILCR was within the acceptable range (10-6 to 10-4), indicating low health risk to residents