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

BACKGROUND: Exposure to [Formula: see text] arising from solid fuel combustion is estimated to result in [Formula: see text] million premature deaths and 91 million lost disability-adjusted life years annually. Interventions attempting to mitigate 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 HAPIN trial included 3,195 households primarily using biomass for cooking in Guatemala, India, Peru, and Rwanda. Twenty-four-hour exposures to [Formula: see text] , carbon monoxide (CO), and black carbon (BC) were measured for pregnant women once before randomization into control ([Formula: see text]) and LPG ([Formula: see text]) 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 [Formula: see text] ([Formula: see text]) in the intervention arm were lower by 66% at the first (71.5 vs. [Formula: see text]), and second follow-up visits (69.5 vs. [Formula: see text]) compared to controls. BC exposures were lower in the intervention arm by 72% (9.7 vs. [Formula: see text]) and 70% (9.6 vs. [Formula: see text]) at the first and second follow-up visits, respectively, and carbon monoxide exposure was 82% lower at both visits (1.1 vs. [Formula: see text]) in comparison with controls. Exposure reductions were consistent over time and were similar across research locations. DISCUSSION: Postintervention [Formula: see text] 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 [Formula: see text] samples falling below the World Health Organization Annual Interim Target 1 of [Formula: see text]. This study indicates that an LPG intervention can reduce [Formula: see text] exposures to levels at or below WHO targets. https://doi.org/10.1289/EHP10295