Indoor air pollution, cookstove quality, and housing characteristics in two Honduran communities

Elevated indoor air pollution exposures associated with the burning of biomass fuels in developing countries are well established. Improved cookstoves have the potential to substantially reduce these exposures. However, few studies have quantitatively evaluated exposure reductions associated with the introduction of improved stoves, likely due to the cost and time-intensive nature of such evaluations. Several studies have demonstrated the value of estimating indoor air pollution exposures by evaluating personal cooking practices and household parameters in addition to stove type. We assessed carbon monoxide (n=54) and fine particulate matter (PM(2.5)) (n=58) levels among non-smoking Honduran women cooking with traditional or improved wood-burning cookstoves in two communities, one semi-urban and one rural. Exposure concentrations were assessed via 8-h indoor monitoring, as well as 8-h personal PM(2.5) monitoring. Housing characteristics were determined to indicate ventilation that may affect carbon monoxide and PM(2.5). Stove quality was assessed using a four-level subjective scale representing the potential for indoor emissions, ranging from poorly functioning traditional stoves to well-functioning improved stoves. Univariately, the stove scale as compared to stove type (traditional versus improved) accounted for a higher percent of the variation in pollutant concentrations; for example, the stove scale predicted 79% of the variation and the stove type predicted 54% of the variation in indoor carbon monoxide concentrations. In multivariable models, the stove scale, age of the stove, and ventilation factors predicted more than 50% of the variation in personal and indoor PM(2.5) and 85% of the variation in indoor carbon monoxide. Results indicate that using type of stove alone as a proxy for exposure may lead to exposure misclassification and potentially biased exposure and health effects relationships. Utilizing stove quality and housing characteristics that influence ventilation may provide a viable alternative to the more time- and cost-intensive pollutant assessments for larger-scale studies. Designing kitchens with proper ventilation structures could lead to improved indoor environments, especially important in areas where biomass will continue to be the preferred and necessary cooking fuel for some time.