Household Air Pollution Concentrations after Liquefied Petroleum Gas Interventions in Rural Peru: Findings from a One-Year Randomized Controlled Trial Followed by a One-Year Pragmatic Crossover Trial

BACKGROUND: Household air pollution (HAP) from biomass fuel combustion remains a leading environmental risk factor for morbidity worldwide. OBJECTIVE: Measure the effect of liquefied petroleum gas (LPG) interventions on HAP exposures in Puno, Peru. METHODS: We conducted a 1-y randomized controlled trial followed by a 1-y pragmatic crossover trial in 180 women age 25???64 y. During the first year, intervention participants received a free LPG stove, continuous fuel delivery, and regular behavioral messaging, whereas controls continued their biomass cooking practices. During the second year, control participants received a free LPG stove, regular behavioral messaging, and vouchers to obtain LPG tanks from a nearby distributor, whereas fuel distribution stopped for intervention participants. We collected 48-h kitchen area concentrations and personal exposures to fine particulate matter (PM) with aerodynamic diameter ???2.5 ??m (PM2.5), black carbon (BC), and carbon monoxide (CO) at baseline and 3-, 6-, 12-, 18-, and 24-months post randomization. RESULTS: Baseline mean [?? standard deviation (SD)] PM2.5 (kitchen area concentrations 1,220 ?? 1,010 vs. 1,190??880??g/m3; personal exposure 126 ?? 214 vs. 104 ?? 100 ??g/m3), CO (kitchen 53 ?? 49 vs. 50 ?? 41 ppm; personal 7 ?? 8 vs. 7 ?? 8 ppm), and BC (kitchen 180 ?? 120 vs. 210 ?? 150 ??g/m3; personal 19?? 16 vs. 21 ?? 22 ??g/m3) were similar between control and intervention participants. Intervention participants had consistently lower mean (?? SD) concentrations at the 12-month visit for kitchen (41 ?? 59 ??g/m3, 3 ?? 6 ??g/m3, and 8 ?? 13 ppm) and personal exposures (26 ?? 34 ??g/m3, 2 ?? 3 ??g/m3, and 3 ?? 4 ppm) to PM2.5, BC, and CO when compared to controls during the first year. In the second year, we observed comparable HAP reductions among controls after the voucher-based intervention for LPG fuel was implemented (24-month visit PM2.5, BC, and CO kitchen mean concentrations of 34 ?? 74 ??g/m3, 3 ?? 5 ??g/m3, and 6 ?? 6 ppm and personal exposures of 17 ?? 15 ??g/m3, 2 ?? 2 ??g/m3, and 3 ?? 4 ppm, respectively), and average reductions were present among intervention participants even after free fuel distribution stopped (24-month visit PM2.5, BC, and CO kitchen mean concentrations of 561 ?? 1,251 ??g/m3, 82 ?? 124 ??g/m3, and 23 ?? 28 ppm and personal exposures of 35 ?? 38 ??g/m3, 6 ?? 6 ??g/m3, and 4 ?? 5 ppm, respectively). DISCUSSION: Both home delivery and voucher-based provision of free LPG over a 1-y period, in combination with provision of a free LPG stove and longitudinal behavioral messaging, reduced HAP to levels below 24-h World Health Organization air quality guidelines. Moreover, the effects of the intervention on HAP persisted for a year after fuel delivery stopped. Such strategies could be applied in LPG programs to reduce HAP and potentially improve health. https://doi.org/10.1289/EHP10054

Automated summary

This study aimed to measure the effect of liquefied petroleum gas (LPG) interventions on household air pollution (HAP) exposures from biomass fuel combustion in Puno, Peru. The study found that providing free LPG stoves, continuous fuel delivery, regular behavioral messaging, and vouchers for LPG fuel can reduce HAP to levels below World Health Organization air quality guidelines. Furthermore, the effects of the intervention on HAP persisted for a year after fuel delivery stopped.