Development and implementation of clean cooking technology for households in low and middle income countries (LMICs) offer enormous promise to advance at least five Sustainable Development Goals (SDGs): 3. Good health and well-being; 5. Gender equality; 7. Affordable and clean energy; 13. Climate action; 15. Life on land. Programs are being implemented around the world to introduce alternative cooking technologies, and we are well on the way to achieving the goal set by the Global Alliance for Clean Cookstoves to reach 100 million homes with cleaner and more efficient cooking methods by 2020. Despite evidence that household air pollution (HAP) from solid fuel combustion is responsible for 3–4 million early deaths per year, many cookstove programs are motivated and/or financed by climate change mitigation schemes and deploy alternative stoves that use solid fuels such as wood and charcoal. However, recent studies have demonstrated that improved biomass-burning stoves typically only incrementally improve air quality and yield modest or minimal health benefits. Likewise, their contributions to climate change mitigation and other SDGs may be limited. Evidence indicates that cleaner fuels, such as liquefied petroleum gas (LPG), ethanol and biogas, offer greater potential benefits not only to health, but also greater progress towards climate goals and other relevant SDGs. We present a modeled estimate of these potential gains for a diverse group of 40 LMICs. Our model suggests that cookstove programs using LPG stoves and fuel will yield greater reductions in both Disability Adjusted Life Years and Global Warming Commitment in these countries than those using improved biomass stoves. Cost and infrastructure requirements for clean fuels such as LPG are widely recognized constraints. In view of these constraints we present an analytical method to simultaneously consider health and climate needs at the national level for the same 40 countries in the context of estimated LPG expansion potentials. Comparative analyses integrating priorities across SDGs at the national and regional levels may guide more practical and effective household energy development choices going forward.

Approximately 3 billion people, most of whom live in Asia, Africa, and the Americas, rely on solid fuels (i.e. wood, crop wastes, dung, charcoal) and kerosene for their cooking needs. Exposure to household air pollution from burning these fuels is estimated to account for approximately 3 million premature deaths a year. Cleaner fuels – such as liquefied petroleum gas, biogas, electricity, and certain compressed biomass fuels – have the potential to alleviate much of this significant health burden. A wide variety of clean cooking intervention programs are being implemented around the world, but very few of these efforts have been analyzed to enable global learning. The Clean Cooking Implementation Science Network (ISN), supported by the U.S. National Institutes of Health (NIH) and partners, identified the need to augment the publicly available literature concerning what has worked well and in what context. The ISN has supported the development of a systematic set of case studies, contained in this Special Issue, examining clean cooking program rollouts in a variety of low- and middle-income settings around the world. We used the RE-AIM (reach, effectiveness, adaptation, implementation, maintenance) framework to coordinate and evaluate the case studies. This paper describes the clean cooking case studies project, introduces the individual studies contained herein, and proposes a general conceptual model to support future planning and evaluation of household energy programs.

Introduction: Household air pollution from solid fuel combustion for cooking and heating is a leading cause of childhood morbidity and mortality worldwide. We hypothesised that clean cooking interventions delivered during pregnancy would improve child health. Methods: We conducted a cluster randomised trial in rural Ghana to test whether providing pregnant women liquefied petroleum gas (LPG) cookstoves or improved biomass cookstoves would reduce personal carbon monoxide and fine particulate pollution exposure, increase birth weight and reduce physician-assessed severe pneumonia in the first 12 months of life, compared with control participants who continued to cook with traditional stoves. Primary analyses were intention-to-treat. The trial was registered with ClinicalTrials.gov and follow-up is complete. Results: Enrolment began on 14 April 2014, and ended on 20 August 2015. We enrolled 1414 pregnant women; 361 in the LPG arm, 527 in the improved biomass cookstove arm and 526 controls. We saw no improvement in birth weight (the difference in mean birth weight for LPG arm births was 29 g lighter (95% CI −113 to 56, p=0.51) and for improved biomass arm births was 9 g heavier (95% CI −64 to 82, p=0.81), compared with control newborns) nor severe child pneumonia (the rate ratio for pneumonia in the LPG arm was 0.98 (95% CI 0.58 to 1.70; p=0.95) and for the improved biomass arm was 1.21 (95% CI 0.78 to 1.90; p=0.52), compared with the control arm). Air pollution exposures in the LPG arm remained above WHO health-based targets (LPG median particulate matter less than 2.5 microns in diameter (PM_2.5) 45 µg/m³; IQR 32–65 vs control median PM_2.5 67 µg/m³, IQR 46–97). Conclusions: Neither prenatally-introduced LPG nor improved biomass cookstoves improved birth weight or reduced severe pneumonia risk in the first 12 months of life. We hypothesise that this is due to lower-than-expected exposure reductions in the intervention arms. Trial registration number: NCT01335490.