Exposure Contrasts of Pregnant Women during the Household Air Pollution Intervention Network Randomized Controlled Trial

BACKGROUND: Exposure to PM2.5 arising from solid fuel combustion is estimated to result in 2.3 million premahue deaths and 91 million lost disability-adjusted life years annually. Interventions attempting to mitiQate this burden have had limited success in reducing exposures to levels thought to provide substantive health benefits. OBJECTIVES: This paper reports exposure reductions achieved by a liquified petroleum gas (LPG) stove and fuel intervention.for pregnant mothers in the Household Air Pollution Intervention Network (HAPIN) randomized controlled trial. METHODS: The HAPLN trial included 3,195 households primarily using biomass for cooking in Guatemala, India, Peru, and Rwanda. Twenty-fourhour exposures to PM2.5, carbon monoxide (CO), and black carbon (BC) were measured for pregnant women once before randomization into control (n =1,605) and LPG =1,590) arms and twice thereafter (aligned with trimester). Changes in exposure were estimated by directly comparing exposures between intervention and control arms and by using linear mixed-effect models to estimate the impact of the intervention on exposure levels. RESULTS: Median postrandomization exposures of particulate matter (PM) with aerodynamic diameter <2.5 mu m (PM2.5) in the intervention arm were, lower by 66% at the first (71.5 vs. 24.1 mu g/m(3)), and second follow-up visits (69.5 vs. 23.7 mu g/m(3)) compared to controls. BC exposures were lower in the intervention arm by 72% (9.7 vs. 2.7 mu g/m(3)) and 70% (9.6 vs. 2.8 mu g/m(3)) at the first and second follow-up visits, respectively, and carbon monoxide exposure was 82% lower at both visits (1.1 vs. 0.2 ppm) in comparison with controls. Exposure reductions were consistent over time and were similar across research locations. DISCUSSION: Postintervention PM2.5 exposures in the intervention arm were at the lower end of what has been reported for LPG and other clean fuel interventions, with 69% of PM2.5 samples falling below the World Health Organization Annual Interim 'target 1 of 35 mu g/m(3). This study indicates that an LPG intervention can reduce PM2.5 exposures to levels at or below WHO targets.