Ethyne Furan Ratios as Indicators of High and Low Temperature p-PAH Emissions from Household Stoves in Haryana India

Emission factors of 16 particle-bound polycyclic aromatic hydrocarbons (16 p-PAHs) from residential fuel combustion are highly variable, resulting in significant uncertainty with respect to the estimation of emissions of PAHs from this sector. Emissions of 16 p-PAHs were characterized during daily cooking activities for two traditional Indian cookstoves: the angithi, which burns dung, and the chulha, using brushwood, dung, and a mix of brushwood and dung fuels. Previous work has shown that ethyne–furan ratios are reasonable predictors of high- and low-temperature pyrolysis that explain most of the variability in volatile organic compound (VOC) emissions from biomass burning. Here, we demonstrate that, as the ethyne–furan ratio increases in these stoves, the 2- and 3-ring p-PAHs account for a smaller fraction of summed 16 p-PAHs and emissions of high molecular weight p-PAHs and elemental carbon (EC) increase. This indicates a shift from less to more fused ring p-PAHs, leading to higher EC emissions. Similar to studies of VOC emissions from biomass burning, 16 p-PAH emissions from the same stove type varied widely and were not related to modified combustion efficiency, thus suggesting that larger numbers of field studies are required to adequately capture these emissions using inventories. In addition, in these stoves, fluoranthene and pyrene ratios used in source apportionment overlap with ratios typically used to identify fossil-fuel burning and thus do not adequately constrain these sources.