Trial design and study settings
The HAPIN trial was a randomized controlled trial of LPG stoves and free fuel distribution conducted in 3200 households across four low-and middle-income countries with primarily rural study settings with a range of elevations: India (Tamil Nadu, 2 study sites), Guatemala (Jalapa municipality, 1 study site) Peru (Department of Puno, 6 study sites) and Rwanda (Eastern Province, 1 study site). In an effort to increase generalizability, the study sites were chosen to represent diverse characteristics from altitude, cooking practices, and baseline pollution levels. The mean travel time to the nearest health facility from any location in the study areas ranged from 15 to 48 min (