The underlying concept behind this feasibility trial is to achieve a reduction in indoor smoke from biomass fuels and minimize changes in cooking practices such that it prompts one of the two improved, ventilated cookstoves to be the selection of choice. Typical fuel sources used in developing countries include wood, dried dung, and agricultural waste. The investigators propose to reduce indoor air pollution by replacing the household traditional cookstove with an improved design that incorporates the following key elements:

• Burner openings customized to the size and shape of the cooking vessels in the home.
• Flue designed to draw air into the fire box under the cooking pots and pass it out through a chimney.
• A chimney with adequate height to create a draft and vented to the exterior.
• An exterior port that has bidirectional openings to prevent backflow of smoke.
• An access port for the chimney that permits cleaning of soot.

The investigators propose to use two types of improved cookstoves that meet these criteria. As part of piloting activities, the investigators will test several different types of commercially-available cookstoves with a chimney, and we may also want to test a locally-made improved cookstove. The investigators want to evaluate those designs by comparing their ability to reduce indoor air pollution, the reliability between cookstoves of the same type, the functioning over time, the logistics of import/build locally, preferences and cultural compatibility, and costs. The investigators will select two types of improved cookstoves to use in the feasibility trial.

The study design will be a crossover intervention trial in which all patients will first have a run-in observational period of 4 months with the traditional cookstove prior to randomization. At baseline, the investigators will obtain sociodemographic information for each household, respiratory outcomes and other health data for the participating women, and cooking times and practices including the types of fuels used. All 40 patients at each site will receive the two types of improved cookstoves, one after the other: 20 will be randomized to receive the first type of cookstove with a chimney and the other 20 to first receive the second type of improved cookstove with a chimney. The patients will be followed for 4 months before the crossover. The investigators will assess cooking behavioral practices and compliance with cookstove use monthly, and respiratory and environmental measures at the mid-point of the 4 month period to minimize carry-over effects. At the end of second 4 month period, the investigators will switch the order of the improved cookstoves and follow all participants for another 4 months. The investigators will assess behavior, compliance, respiratory and environmental measures as above. The study is expected to require 12 months to complete.

Inclusion Criteria:

• Have at least one woman aged 20 to 49 years who is the main cook.
• Have a traditional (i.e., open-fire) cookstove indoors with at least 3 walls and a roof.
• Are willing to have us install an improved cookstove and be willing to use it.
• Have household walls of mud, brick, cement, or wood.
• Capable of providing informed consent and responding to a questionnaire
• Full-time resident in the area

Exclusion Criteria:

• Have a new improved cookstove or a chimney in the household.
• Have household walls of thatch or bamboo no covered in mud.
• Plans to move from the area within one year.