Familial variation in personal PM2.5 exposure within a rural Rwandan community pre and post clean energy intervention

Abstract

Exposure to fine particulate matter (PM2.5) from solid fuel combustion is a major determinant of global morbidity and mortality. However, demographic variations in personal exposure remain uncertain across many high-risk populations. Liquefied petroleum gas (LPG) stoves have been proven to emit far less PM2.5 than traditional biomass burning stoves and significantly reduce personal exposures in randomized control trials. However, there is uncertainty surrounding the difference in exposure reductions produced by LPG stove interventions among men, women, and children. This work describes personal PM2.5 exposures and exposure reductions among household members (adult men, adult women, and children) in rural sub-Saharan Africa, where biomass fuel was the primary household energy source, before and during a whole-household energy intervention. LPG stoves were used to replace traditional biomass burning stoves, and solar-based electric lighting replaced traditional kerosene lamps. Personal PM2.5 exposures were assessed using wearable monitors that combined real-time sensing, time-integrated (gravimetric filter) sampling, and continuous location-activity tracking over 48-hr sampling periods. First, the baseline variation in PM2.5 exposures among adults (men and women) and adolescent/pre-adolescent children within two rural Rwandan villages was assessed prior to the introduction of clean energy technology, when all participants still relied on their traditional forms of household energy. Linear mixed models, controlling for household, were used to examine the variation in baseline exposures among family members. A spaciotemporal analysis was also employed to apportion personal PM2.5 exposures into unique time-activity patterns, revealing previously unknown behavioral patterns between the demographics. For the intervention phase of the study, an intent-to-treat (ITT) framework was used to examine the variation in personal PM2.5 exposure reductions achieved by the whole-household energy intervention among men, women, and children within the community. Results from this analysis indicate that interventions for household energy systems, in conjunction with familial lifestyle and behavior modifications, are necessary to reduce personal PM2.5 exposures in rural sub-Saharan African communities.