The Global Burden of Disease Study 2010 estimates that exposure to smoke from the simple act of cooking is the fourth worst risk factor for disease in developing countries, and causes four million premature deaths per year – exceeding deaths attributable to malaria or tuberculosis. In addition, tens of millions more fall sick with illnesses that could readily be prevented with increased adoption of clean and efficient cooking solutions.
Women in developing countries are also at risk of head and spinal injuries, pregnancy complications, and maternal mortality from the strenuous task of carrying heavy loads of firewood or other fuels. Frequent exposure to cookstove smoke can also cause disabling health impacts like cataracts, which affect women more than men, and is the leading cause of blindness in developing countries.
Exposure to smoke is greatest among women and young children, who spend the most time near open fires or traditional cookstoves tending to the family meal, or schoolchildren who may study by the light of an open flame. Both inhale unhealthy levels of emissions. Rudimentary wood-fired cookstoves and open fires emit fine particles, carbon monoxide, and other pollutants at levels up to 100 times higher than the recommended limits set by WHO .
Health effects are especially deadly for children under the age of five. A randomized-control study in Guatemala led by the University of California, Berkeley, found that halving exposure to indoor air pollution with a chimney stove brought about a reduction in severe pneumonia, and that larger reductions in exposure had more pronounced effects. A systematic review of all available studies on the link between solid fuel use and child pneumonia has found an almost doubling of risk for those exposed.
Burns from open fires and unsafe cookstoves are another insidious risk faced by poor households dependent on kerosene, open fires, and unstable metal or clay cookstoves, contributing to a substantial percentage of the estimated 300,000 burn deaths that occur annually. Because burns require prompt and sophisticated medical intervention often lacking in remote areas of the world, such injuries often result in debilitating scarring and loss of movement in their victims.
While the link between exposure to cookstove smoke and a wide range of health problems such as pneumonia, chronic obstructive pulmonary disease, and lung cancer is well established, the current body of evidence linking cookstoves with other potentially important health effects is compelling but less documented. In addition, important gaps and weaknesses in the evidence base for other potentially important health outcomes, including developmental effects, adult pneumonias, cardiovascular disease, and tuberculosis, remain.
Nearly all of the existing evidence is based on observational studies that compare groups using open fires and traditional cookstoves with those using cleaner fuels, with very little being directly obtained from studies that directly measure the effects of interventions.
More evidence is needed to demonstrate that the levels of exposure reduction delivered by clean cookstove and fuels will result in declines in related illnesses and deaths. This evidence will help guide intervention strategies, benchmark standards, and make the most compelling case for large-scale investment in this area.
Research priorities identified by the Alliance include:
- Describing relationships between exposure level and risk of disease on health (such as child pneumonia, low birth weight/pre-term birth, etc.);
- Demonstrating impacts on health of interventions (with a focus on children’s health and chronic disease) that reduce exposure in laboratory and field settings, and increase overall safety;
- Strengthening evidence through a range of intervention and non-intervention based research designs to assess the risk of diseases for which there is currently only weak and/or inconsistent evidence (e.g. tuberculosis, adult pneumonia, other cancers, and asthma);
- Developing responses that incorporate the broader group of combustion sources of pollution, including indoor/household, ambient, and cigarette smoke (active and second-hand smoke) would measure the health effects of household air pollution;
- Obtaining information on the incidence, severity and causes of cookstove burns, scalds and other injuries (e.g. liquid fuel ingestion), further developing and testing existing safety protocols, and carrying out field evaluation to determine the impacts on these outcomes of cleaner stoves/fuels.
For the full set of recommendations made by the HWG, Download The Working Group Recommendations