Characterization and Determination of PM2.5 Bound Polycyclic Aromatic Hydrocarbons (PAHS) in Indoor and Outdoor Air in Western Sierra Leone

Abstract

Eleven airborne PM2.5 PAH concentrations were characterized in the kitchen, outdoor and living room environments in households that burn wood and charcoal fuels in Western Sierra Leone, during a survey that was conducted in September 2011. The average concentration of total PAHs (Σ11PAHs) was 1279.7 ng/m3 in kitchen, 41.2 ng/m3 in outdoor, 19.8 ng/m3 in living room for households burning wood while those burning charcoal was 96.5 ng/m3, 13.1 ng/ m3 and 8.9 ng/m3 in the kitchen, outdoor and living room, respectively. The percentage contribution of higher molecular weight PAHs to Σ11PAHs was about 25% higher compared to medium molecular weight PAHs for either household category in all three locations, with a somewhat different scenario for kitchens with wood stove. The ratio of indoor/ outdoor air of Σ11PAHs showed considerable variation among households burning charcoal (p=0.0021; t-test) relative to those burning wood, attributed to non-prolonged equilibrium between the two environments. Benzo(a)pyrene (BaP) equivalency results revealed that BaP and dibenzo(a,h)anthracene were the two most dominant compounds that contributed to more than 90% of the total carcinogenicity in all three environments for households burning wood and charcoal. The results suggest that kitchens, where biomass fuels are burnt continue to be a hazardous place for people of developing countries to spend their time.