The impact of improved wood-burning stoves on fine particulate matter concentrations in rural Mexican homes

Abstract

To evaluate the impact of improved wood burning stoves on indoor air pollution, 53 homes in a rural town in Michoacán, Mexico, were selected from a health intervention study and monitored before and after receiving improved wood-burning stoves. Fine particulate matter — particles with aerodynamic diameter less than 2.5 m (PM_2.5) — concentrations were measured in the central plaza of the community and in three microenvironments in the home (next to the stove, in the kitchen away from the stove, and outdoor patio). Forty-eight hour mean PM_2.5 concentrations in homes that burned wood in open fires were 693 g/m³ (95% CI: 246–1338) near the stove, 658 g/m³ (95% CI: 67–1448) in the kitchen away from the stove, and 94 g/m³ (95% CI: 36–236) on the patio. Mean ambient 24-h concentrations in the main plaza of the community were 59 g/m³ (95% CI: 29–92). Paired measurements before and after the installation of the Patsari improved wood-burning stove indicate a median 71% reduction in PM_2.5 concentrations near the stove and 58% reductions in kitchen concentrations, whereas patio and main plaza concentrations remain unaffected. Only 44% of participants reported to use their Patsari stoves exclusively during the transition period. Even with the predominant mixed use of the Patsari stove with open fires, estimated daily average personal exposures to PM_2.5 were reduced by 50%.