Size-distribution and driving factors of aerosol oxidative potential in rural kitchen microenvironments of northeastern India

This study reports size-resolved dithiothreitol (DTT)-based oxidative potential (OP: total and water-soluble) in rural kitchens using liquefied petroleum gas (LPG), firewood (FW), and mixed biomass (MB) fuels in northeastern (NE) India. In comparison to LPG, volume-normalized total OP (OP total(v) DTT ) was enhanced by a factor of ∼5 in biomass-using kitchens (74 ± 35 to 78 ± 42 nmol min −1 m −3 ); however, mass-normalized total OP (OP total(m) DTT ) was similar between LPG and FW users and higher by a factor of 2 in MB-using kitchens. The water-insoluble OP (OP wi(v, m) DTT ) fraction in OP total(v, m) DTT was greater than 50% across kitchens. Size distributions across kitchens and OP DTT categories ranged from unimodal to trimodal. OP ws(v) DTT was driven by metals as well as organics across size fractions while OP wi(v) DTT was majorly constrained by metals with an increasing importance of organics in fine particles of biomass-using kitchens. Multiple linear regression analysis revealed that Cu and Ba explained 71% of the OP total(v) DTT variability in LPG-using kitchens, while water-soluble organic carbon (WSOC) and Ba were responsible for 44% variability in FW-using kitchens. Finally, the high internal dose of OP total(v) DTT (28–31 nmol min −1 m −3 ) in biomass-using kitchens established the severity of oxidative stress on the exposed population.