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

Abstract

Background: Exposure to arising from solid fuel combustion is estimated to result in 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 , carbon monoxide (CO), and black carbon (BC) were measured for pregnant women once before randomization into control ( ) and LPG ( ) 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 ( ) in the intervention arm were lower by 66% at the first (71.5 vs. ), and second follow-up visits (69.5 vs. ) compared to controls. BC exposures were lower in the intervention arm by 72% (9.7 vs. ) and 70% (9.6 vs. ) at the first and second follow-up visits, respectively, and carbon monoxide exposure was 82% lower at both visits (1.1 vs. ) in comparison with controls. Exposure reductions were consistent over time and were similar across research locations. Discussion: Postintervention 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 samples falling below the World Health Organization Annual Interim Target 1 of . This study indicates that an LPG intervention can reduce exposures to levels at or below WHO targets. https://doi.org/10.1289/EHP10295

Effects of a Liquefied Petroleum Gas Stove Intervention on Gestational Blood Pressure: Intention-to-Treat and Exposure-Response Findings From the HAPIN Trial

“…Exposure measurement procedures have been described previously. 29,32 While there is no gold standard for measuring HAP, gravimetric measures—of the type we performed—are considered high quality, especially when performed with stringent QA-QC procedures. 32 Personal exposure monitoring was conducted during the 24 hours before the BP measurements.…”

“…29,32 While there is no gold standard for measuring HAP, gravimetric measures—of the type we performed—are considered high quality, especially when performed with stringent QA-QC procedures. 32 Personal exposure monitoring was conducted during the 24 hours before the BP measurements. We measured personal exposures to PM 2.5 , BC, and CO at baseline and at the 2 follow-up visits.…”

“…If a gravimetric sample was considered invalid due to a missing or damaged filter or flow faults, instrument-specific nephelometric concentrations were used instead, normalized to field-based filter samples. 32 Personal exposure to BC was estimated from PM 2.5 filter samples with SootScan Model OT21 Optical Transmissometers (Magee Scientific). CO concentrations were measured using the Lascar EL-USB-300 (Lascar Electronics) at 1-minute intervals with range between 0 and 300 ppm.…”

Breathing Room: Cleaner Fuels for Home Cooking in LMICs

“…The recently completed Household Air Pollution Intervention Network (HAPIN) trial 9 offers robust evidence that in a best-case scenario, with LPG stoves and cylinders provided free of charge, residents’ exposures to fine particulate matter ( ) can be brought below interim guidelines established by the WHO. 10 …”

Invited Perspective: A Critical Part of a Real-World Environmental Health Trial Is to Demonstrate That the Intervention Reduced Exposure

“…report that the Household Air Pollution Intervention Network (HAPIN) trial appears to have overcome the challenges involved in reducing exposures. 5 The next step is to demonstrate health improvements.…”