The goal of this research is to determine the feasibility of conducting a cookstove intervention trial with two types of cookstoves in three rural populations in Kenya, Nepal and Peru. Our ultimate goal is to characterize the adverse effects of cooking with traditional cookstoves and determine preferences for the type of cookstove, Specifically, we plan to perform a community-based feasibility trial in which we will install improved cookstoves with a chimney in 40 rural households of women aged 35 to 45 years at each of the three sites. All households will have a baseline observational period of 4 months in which we will collect outcome, environmental, and behavioral data longitudinally. Thereafter, 20 households will be randomly assigned to receive a commercially-available, improved cookstove with a chimney or a locally-constructed improved cookstove with a chimney. We will collect behavioral, compliance, outcome and exposure data longitudinally for 4 months. Exposure assessments will include particulate matter and carbon monoxide. Respiratory outcome assessment will include spirometry, carboxyhemoglobin, exhaled nitric oxide and diffusing capacity of the lung for carbon monoxide. At the end of 4 month period, households that received the Envirofit improved cookstoves will have their cookstoves switched with the locally-constructed improved cookstoves and vice versa, and all households will be followed for another 4 months. At the end of the year, all participants will be asked which cookstove they prefer and will be asked provide information on preferences, practices, and use patterns that influenced their final choice.