Monitoring of traditional stove use in the context of a clean fuel (liquefied petroleum gas, LPG) intervention trial in Guatemala, India, Peru, and Rwanda

Background: The Household Air Pollution Intervention Network (HAPIN) trial enrolled 3200 pregnant women who cooked with biomass fuel in Guatemala, India, Peru, and Rwanda; half were randomized to receive a liquefied petroleum gas (LPG) stove, approximately 18 months of free LPG, and behavioral messaging to promote LPG use. Although the intervention was designed to enable exclusive LPG use, investigators expected that some traditional stove use (TSU) would persist among intervention households. Methods: Thermocouple stove use monitors (SUMs, Geocene, Inc, Vallejo, USA) were installed on traditional stoves in intervention households. Data from SUMs were downloaded approximately every two weeks and TSU identified using a sensitive, deterministic algorithm. HAPIN fieldworkers visited households with detectable TSU events to administer a questionnaire on the reasons for TSU and reinforce exclusive LPG use. Results: Over 454,281 post-intervention household-days of monitoring among 1548 households (400 in Guatemala, 398 in India, 357 in Peru, and 393 in Rwanda), the rate of days with TSU per 100 household-days of observation was 0.83 (1.2 in Guatemala, 0.06 in India, 1.3 in Peru, and 0.8 in Rwanda). 95.1% of all households recorded one or no days with TSU on average per month (96.2% in Guatemala, 99.7% in India, 87.9% in Peru, and 95.9% in Rwanda). Primary reasons reported for TSU included: challenges with timely requests or receipt of LPG refills; resistance of other household members to LPG; uncertainty about how to clean, maintain, or check the LPG stove; and inability to cook large quantities of food with LPG. Conclusions: In the context of a free stove-and-fuel intervention combined with behavioral strategies to encourage exclusive LPG use, TSU events, measured by SUMs and direct observation, were infrequent at trial midpoint. The combination of SUMs data with household questionnaires provides a rich understanding of TSU persistence in the context of free LPG.