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

Abstract

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 $\le 2.5\mu m$ (${\mathrm{PM}}_{2.5}$), black carbon (BC), and carbon monoxide (CO) at baseline and 3-, 6-, 12-, 18-, and 24-months post randomization.

Results: Baseline $\text{mean}[\pm \text{standard deviation}(\text{SD}\left)\right]$ ${\mathrm{PM}}_{2.5}$ (kitchen area concentrations $\mathrm{1,220}\pm \mathrm{1,010}$ vs. $\mathrm{1,190}\pm 880{\mu g/m}^3$; personal exposure $126\pm 214$ vs. $104\pm 100{\mu g/m}^3$), CO (kitchen $53\pm 49$ vs. $50\pm 41\text{ppm}$; personal $7\pm 8$ vs. $7\pm 8\text{ppm}$), and BC (kitchen $180\pm 120$ vs. $210\pm 150{\mu g/m}^3$; personal $19\pm 16$ vs. $21\pm 22{\mu g/m}^3$) were similar between control and intervention participants. Intervention participants had consistently lower $\text{mean}\left(\pm \text{SD}\right)$ concentrations at the 12-month visit for kitchen ($41\pm 59{\mu g/m}^3$, $3\pm 6{\mu g/m}^3$, and $8\pm 13\text{ppm}$) and personal exposures ($26\pm 34{\mu g/m}^3$, $2\pm 3{\mu g/m}^3$, and $3\pm 4\text{ppm}$) to ${\mathrm{PM}}_{2.5}$, 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 ${\mathrm{PM}}_{2.5}$, BC, and CO kitchen mean concentrations of $34\pm 74{\mu g/m}^3$, $3\pm 5{\mu g/m}^3$, and $6\pm 6\text{ppm}$ and personal exposures of $17\pm 15{\mu g/m}^3$, $2\pm 2{\mu g/m}^3$, and $3\pm 4\text{ppm}$, respectively), and average reductions were present among intervention participants even after free fuel distribution stopped (24-month visit ${\mathrm{PM}}_{2.5}$, BC, and CO kitchen mean concentrations of $561\pm \mathrm{1,251}{\mu g/m}^3$, $82\pm 124{\mu g/m}^3$, and $23\pm 28\text{ppm}$ and personal exposures of $35\pm 38{\mu g/m}^3$, $6\pm 6{\mu g/m}^3$, and $4\pm 5\text{ppm}$, 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.

Trial registration: ClinicalTrials.gov NCT02994680.