Estimation of polycyclic aromatic hydrocarbons associated with size segregated combustion aerosols generated from household fuels

Abstract

Combustion of household fuels is the major source of polycyclic aromatic hydrocarbons (PAHs) in indoor environment. The quantity and quality of PAHs in indoor environment depend on the choice of household fuels and combustion conditions (ventilation, stove type, moisture content of fuel, etc.). In present study, the mass size distribution of combustion aerosol and size fractionated PAHs (sixteen) was evaluated for most commonly used household fuels viz. firewood, coal, dung cake, kerosene and LPG. Variable configuration cascade impactor (VCCI) was used for aerosol collection, and subsequent analysis of PAHs was carried out using high performance liquid chromatography (HPLC) coupled with UV detector. For solid fuels (firewood, coal, dung cake) mass concentration was found maximum in accumulation mode i.e., size range 0.75–2.23μm. The kerosene and LPG generated aerosols were found to be distributed all over the measured size bin (>21 to <0.1μm). It was found that most of the PAHs are associated with 0.75–1.13μm size range of particle for combustion aerosols. Firewood, coal and kerosene emit maximum PAHs associated with fine fraction, while PAH content for LPG was found to be more or less same in all size fractions. Solid biomass generates more higher molecular weight (five or more rings) PAHs compared to non-solid fuels such as kerosene and LPG, while the latter are mainly emitting two and three ring PAHs. The formation of multiple ring PAHs is a function of combustion temperature which may vary according to fuel type and methods of combustion. Data of PAH contents in different size fraction of tested fuels can be used for PAH markers.