Assessment of effectiveness of improved cook stoves in reducing indoor air pollution and improving health in Nepal

Abstract

The mud improved cook stove (ICS) is a popular household energy intervention in rural Nepal. This research monitoring was designed to assess the impact of mud ICS, promoted by the Nepali national cook stove program, in reducing indoor air pollution (IAP).This study employed a longitudinal, “Before and After” research design described previously by Edwards et al. (2007). Mean 24h PM2.5 (particulate matter less than 2.5 micrometers in aerodynamic diameter) and CO (carbon monoxide) concentrations were measured in the kitchen. A preliminary health survey was also conducted to evaluate the reported changes in key respiratory symptoms. The study was conducted at three geographically different sites with a sample size of 47 households. Household pollution monitoring was conducted in two phases — 3months and 12months post installation of the ICS.After 1year of ICS use, the mean values of PM2.5 and CO were reduced 63.2% and 60.0% respectively. PM2.5 concentration was significantly lowered from 2.07mg/m3 (95 % CI: 1.42–2.71) during traditional cook stove (TCS) use to 0.76mg/m3 (95 % CI 0.521–1.00) during ICS use. The mean CO concentration was reduced significantly from 21.5ppm (95 % CI: 14.5–28.6) to 8.62ppm (95% CI: 6.18–11.1). Comparison of 3-month and 12-month post-installation mean PM2.5 and CO concentrations in homes with an ICS was not significantly different. The health survey preliminarily indicated changes in cough, phlegm, and eye irritation in ICS users.The study establishes that the mud ICS is an appropriate intervention to reduce PM2.5 and CO in rural kitchens. This study recommends greater focus on proper operation and maintenance of ICS and ventilation to lower the smoke level even further.