This pilot study is based in the Pune district of India, and is structured to monitor environmental exposures within rural households that utilize biomass materials such as wood or animal dung as primary fuel sources for cooking. The combined use of primitive cook stove technology with biomass fuel is prevalent in the rural, semi-urban, and slum areas of India, generating high concentrations of indoor air pollutants. Consequently, epidemiologic studies using cross-sectional designs have associated biomass smoke exposure with elevated risk for numerous adverse health impacts, including respiratory irritation and inflammation, cardiovascular disease, impaired immune systems response, and chronic obstructive pulmonary disease (COPD). For this pilot study, a crossover design will be employed to test the hypothesis that changing from biomass cooking fuel to liquid petroleum gas (LPG) will result in reduced environmental exposure over a short period of time. Ten households will be recruited, and the indoor air quality of the households will be evaluated during use of traditional biomass cook stoves and LPG. Researchers from the Chest Research Facility, in Pune, may also complete a separate study in parallel, testing the hypothesis that the change in cooking fuel will result in reduced markers of pulmonary and systemic inflammation and oxidative stress over the same time period. To complete this study we will conduct the following data and activities: Daily indoor measures of fine airborne particulate matter (PM2.5), carbon monoxide (CO), and nitrogen dioxide (NO2) exposure Observations of cooking habits, personal health, and behavior towards stove technologies