Impact of biomass stove intervention on indoor air quality in rural homes of China: Attenuation of cooking contribution.

Biomass fuels are used extensively for cooking globally, posing a severe health threat to more than 2.50 billion people. However, while improved biomass stoves can reduce average pollutant concentrations, their effects on short-term pollution dynamics and inter-room pollutant transport remain poorly understood. This study implemented an advanced biomass intervention in rural households of Xuanwei, Yunnan Province, utilizing real-time monitors to measure PM2.5 concentrations in kitchen, living room, bedroom, and yard. Results showed that stove intervention reduced daily mean PM2.5 levels across all microenvironments. Kitchen PM2.5 concentrations declined by 29.3%, 55.8%, and 30.7% for households adopting direct-fired, recirculating, and gasifier stoves, respectively. High-temporal-resolution analysis further showed substantial attenuation of cooking-related PM2.5 peaks following stove intervention, especially in households using gasifier stoves which reduced cooking peak height and area by 59.3% and 60.2% in kitchen, respectively. Correspondingly, the contribution of cooking activities to kitchen PM2.5 decreased by approximately 30.0%, suggesting that stove replacement attenuated cooking-related pollution. In households using gasifier stoves, the indoor-to-outdoor PM2.5 ratios in living rooms and bedrooms approached unity, suggesting diminished influence from indoor sources. These findings provide preliminary field-based evidence that advanced biomass stoves may mitigate cooking-related PM2.5 pollution and limit its spatial dispersion in biomass-dependent rural households.