Probabilistic single box approach for modeling PAHs associated with combustion aerosols in a typical indoor environment

Firewood, coal, dung cake, kerosene and Liquefied Petroleum Gas (LPG) are the most commonly used fuels for cooking and heating purposes in developing countries. Combustion of such fuels leads to high concentrations of pollutants in the indoor environment. Polycyclic aromatic hydrocarbons (PAHs) are emitted during residential combustion, and have carcinogenic and genotoxic properties. In this study, data from an experimental setup for estimation of emission rate of particulate-bound PAHs generated during combustion of such fuels are used. PAHs emission rates were used in a probabilistic single box model for prediction of time average particle associated indoor B(a)P equivalent (B(a)P_eq) concentrations of PAHs resulting from typical Indian cooking. Model parameters such as fuel consumption rate, stove power and cooking time were also evaluated experimentally. Particle bound B(a)P_eq PAH emission factor was found to be highest (0.96 mg kg⁻¹) for dung cake, and lowest for LPG (0.48 mg kg⁻¹) among tested fuels. The time averaged B(a)P equivalent concentrations in indoor environment were found to be 0.82, 0.45, 0.87, 0.30, and 0.14 μg m⁻³ for firewood, coal, dung cake, kerosene and LPG respectively. Results reveal that there was higher B(a)P equivalent concentration during combustion of biomass (dung cake, fire wood) as compared to fossil fuels (coal) and non-solid fuels (kerosene, LPG). Predicted time averaged indoor air B(a)P_eq concentrations of PAHs were found to be much higher than the WHO indoor air guideline values for all tested fuels.