Impact of the wood-burning Justa cookstove on fine particulate matter exposure: A stepped-wedge randomized trial in rural Honduras

Trial design: We evaluated the impact of a biomass stove intervention on fine particulate matter (PM2.5) concentrations using an individual-level, stepped-wedge randomized trial. Methods: We enrolled 230 women in rural Honduran households using traditional biomass stoves and randomly allocated them to one of two study arms. The Just stove, the study intervention, was locally-sourced, wood-burning, and included an engineered combustion chamber and chimney. At each of 6 visits over 3 years, we measured 24-hour gravimetric personal and kitchen PM2.5 concentrations. Half of the households received the intervention after Visit 2 and half after Visit 4. We conducted intent-to-treat analyses to evaluate the intervention effect using linear mixed models with log-transformed kitchen or personal PM2.5 (separately) as the dependent variable, adjusting for time. We also compared PM2.5 concentrations to World Health Organization (WHO) guidelines. Results: Arms 1 and 2 each had 115 participants with 664 and 632 completed visits, respectively. Median 24-hour average personal PM2.5 exposures were 81 mu g/m(3) (25th-75th percentile: 50-141 mu g/m(3)) for the traditional stove condition (n=622) and 43 mu g/m(3) (25th-75th percentile: 27-73 mu g/m(3)) for the justa stove condition (n=585). Median 24-hour average kitchen concentrations were 178 mu g/m(3) (25th-75th percentile: 69-440 mu g/m(3); n= 629) and 53 mu g/m(3) (25th-75th percentile: 29-103 mu g/m(3); n=578) for the traditional and Justa stove conditions, respectively. The Justa intervention resulted in a 32% reduction in geometric mean personal PM2.5 (95% confidence interval [CI]: 20-43%) and a 56% reduction (95% CI: 46-65%) in geometric mean kitchen PM2.5. During rainy and dry seasons, 53% and 41% of participants with the Justa intervention had 24-hour average personal PM(2.5 )exposures below the WHO interim target-3 guideline (37.5 mu g/m(3)), respectively. Conclusion: The justa stove intervention substantially lowered personal and kitchen PM2.5 and may be a provisional solution that is feasible for Latin American communities where cleaner fuels may not be available, affordable, or acceptable for some time. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study evaluated the impact of a biomass stove intervention on fine particulate matter concentrations, showing significant reductions in PM2.5 levels in both personal and kitchen settings. The Justa stove intervention resulted in a 32% reduction in personal PM2.5 and a 56% reduction in kitchen PM2.5, suggesting it could be a provisional solution for communities where cleaner fuels are not readily available.