Modeling the potential health benefits of lower household air pollution after a hypothetical liquified petroleum gas (LPG) cookstove intervention

Introduction: Improved biomass and advanced fuel cookstoves can lower household air pollution (HAP), but levels of fine particulate matter (PM_2.5) often remain above the World Health Organization (WHO) recommended interim target of 35 μg/m³. Methods: Based on existing literature, we first estimate a range of likely levels of personal PM_2.5 before and after a liquefied petroleum gas (LPG) intervention. Using simulations reflecting uncertainty in both the exposure estimates and exposure-response coefficients, we estimate corresponding expected health benefits for systolic blood pressure (SBP) in adults, birthweight, and pneumonia incidence among children < 2 years old. We also estimate potential avoided premature mortality among those exposed. Results: Our best estimate is that an LPG stove intervention would decrease personal PM_2.5 exposure from approximately 270 μg/m³ to approximately 70 μg/m³, due to likely continued use of traditional open-fire stoves. We estimate that this decrease would lead to a 5.5 mmHg lower SBP among women over age 50, a 338 g higher birthweight, and a 37% lower incidence of severe childhood pneumonia. We estimate that decreased SBP, if sustained, would result in a 5%–10% decrease in mortality for women over age 50. We estimate that higher birthweight would reduce infant mortality by 4 to 11 deaths per 1000 births; for comparison, the current global infant mortality rate is 32/1000 live births. Reduced exposure is estimated to prevent approximately 29 cases of severe pneumonia per year per 1000 children under 2, avoiding approximately 2–3 deaths/1000 per year. However, there are large uncertainties around all these estimates due to uncertainty in both exposure estimates and in exposure-response coefficients; all health effect estimates include the null value of no benefit. Conclusions: An LPG stove intervention, while not likely to lower exposure to the WHO interim target level, is still likely to offer important health benefits.