A rural community intervention targeting biomass combustion sources: Effects on air quality and reporting of children's respiratory outcomes

Objective: Improvements in urban air quality are largely driven by controls on industrial and mobile source emissions, but such factors may have limited influence on many rural environments where biomass combustion (eg, wood stoves) serves as the primary source of fine particulate matter (PM _2.5). The authors tracked changes in children's respiratory health during a wood stove intervention in a rural mountain valley community heavily impacted by wood smoke-derived PM _2.5. Methods: Community-wide impacts on children's health were assessed by prospectively collecting surveys from parents of school children during four winter periods in Libby, Montana. Generalised estimating equations with a logit link were used to estimate the effect of reduction in ambient PM _2.5 on wheeze prevalence and other reported symptoms and infections. Results: Over 1100 wood stoves were replaced with new lower emission wood stoves or other heating sources. Ambient PM _2.5 was 27.6% lower in the winters following the changeout programme compared with baseline winters. There was a 26.7% (95% CI 3.0% to 44.6%) reduced odds of reported wheeze for a 5 μg/m3 decrease in average winter PM2.5. Lower ambient PM _2.5was also associated with reduced odds for reported respiratory infections, including cold (25.4% (95% CI 7.6% to 39.7%)), bronchitis (54.6% (95% CI 24.2% to 72.8%)), influenza (52.3% (95% CI 42.5% to 60.5%)) and throat infection (45.1% (95% CI 29.0% to 57.6%)). Conclusion: This wood stove intervention provided a unique opportunity to prospectively observe health benefits resulting from a targeted air pollution reduction strategy in a rural community.