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 (OPtotal(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 (OPtotal(m)DTT) was similar between LPG and FW users and higher by a factor of 2 in MB-using kitchens. The water-insoluble OP (OPwi(v, m)DTT) fraction in OPtotal(v, m)DTT was greater than 50% across kitchens. Size distributions across kitchens and OPDTT categories ranged from unimodal to trimodal. OPws(v)DTT was driven by metals as well as organics across size fractions while OPwi(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 OPtotal(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 OPtotal(v)DTT (28-31 nmol min-1 m-3) in biomass-using kitchens established the severity of oxidative stress on the exposed population.

Understanding population exposure to size-segregated aerosol and associated trace elements during residential cooking in northeastern India: Implications for disease burden and health risk.

Mass-size distribution of respirable aerosol and 13 associated trace elements (TEs) were investigated in rural kitchens using liquefied petroleum gas (LPG), firewood and mixed biomass fuels across three northeastern Indian states. The averaged PM10 (particulate matter with aerodynamic diameter ≤ 10 µm) and ΣTE concentrations were 403 and 30 µg m-3 for LPG, 2429 and 55 µg m-3 for firewood, and 1024 and 44 µg m-3 for mixed biomass-using kitchens. Mass-size distributions were tri-modal with peaks in the ultrafine (0.05-0.08 µm), accumulation (0.20-1.05 µm), and coarse (3.20-4.57 µm) modes. Respiratory deposition, estimated using the multiple path particle dosimetry model, ranged from 21 % to 58 % of the total concentration across fuel types and population age categories. Head, followed by pulmonary and tracheobronchial, was the most vulnerable deposition region, and children were the most susceptible age group. Inhalation risk assessment of TEs revealed significant non-carcinogenic as well as carcinogenic risk, especially for biomass fuel users. The potential years of life lost (PYLL) was the highest for chronic obstructive pulmonary disease (COPD: 15.9 ± 3.8 years) followed by lung cancer (10.3 ± 0.3 years) and pneumonia (10.1 ± 0.1 years), while the PYLL rate was also highest for COPD, with Cr(VI) being the major contributor. Overall, these findings reveal the significant health burden faced by the northeastern Indian population from indoor cooking using solid biomass fuels.