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The use of biomass solid fuels (BSFs) for cooking, contribute significantly to the household air pollution (HAP) in developing countries. Emissions resulting from a variety of BSFs (cow dung cakes, wood, and agriculture residues) contain a significant amount of air pollutants, which are now recognized for their role in climatic change and adverse human health impacts. In the current study, daily variations in black carbon (BC) or Short-Lived Climate Forcer concentrations were studied from rural household kitchens using portable aethalometer. The hourly average concentration of BC ranges from 5.4 mu g.m(-3) to 34.9 mu g.m(-3) for various types of household kitchens. The peak levels of BC were found to be significantly higher, when compared to World Health Organization PM2.5 limits for ambient air and hence pose a threat to the health of the vulnerable population, i.e., women, children, older adults and those who have health problems. The study also highlights the variation of BC concentration in different kitchen type. The average BC concentration in indoor, outdoor and semi-open kitchen was observed to be 14.54, 14.28 and 24.69 mu g.m(-3), respectively. The excess lifetime carcinogenic risk for cooking 4 h/day in these kitchens in the North Indian villages was estimated to be 1.25 x 10(-7), 1.22 x 10(-7), and 2.12 x 10(-7) respectively. Age-specific excess cancer deaths due to BC exposure were measured highest in children below four years of age in Chandigarh, India. Hence, there is a need to shift the BSF users to clean fuel alternatives to reduce the exposure to HAP. This can be achieved by generating local/regional evidences of BSFs associated health risks to support policy interventions. Further, more research is required to improve the air quality in indoor micro-environments and specifically in kitchens.

Novelty: The first study reporting the near real-time measurements of BC from different types of rural households kitchens of north India. Diurnal pattern of BC concentration was also studied including the effect of chimney, ventilation and kitchen size on observed BC concentration. This study also estimates lifetime excess cancer risk due to BC exposure in rural households in India. The recent 'Global Burden of Disease' report identifies household air pollutants as a major cause of disease and disability in Asia. The study will help to plan suitable policies and intervention to reduce household air pollution in the region.