Policy commentary

Indoor Air Pollution and Africa Death Rates

Sep 15, 2008 | Majid Ezzati
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September 15, 2008
Series Editor: Ian Parry
Managing Editor: Felicia Day
Assistant Editors: John Anderson, Sally Atwater and Adrienne Foerster

Welcome to the RFF Weekly Policy Commentary, which is meant to provide an easy way to learn about important policy issues related to environmental, natural resource, energy, urban, and public health problems.

This week Majid Ezzati discusses the substantial health problems in low-income countries caused by indoor pollution from combustion of traditional cooking and heating fuels. For many regions, there is little prospect of addressing this problem through electrification in the next 20 to 30 years. Nonetheless, some policy interventions, such as encouraging use of less polluting fuels and stoves with better ventilation, can partly address the problem in the meantime, bringing substantial health benefits.


Indoor Air Pollution and African Death Rates

Majid Ezzati

In sub-Saharan Africa, 94 percent of the rural population and 73 percent of the urban population, use biomass—wood, charcoal, crop residues, animal dung—and coal as their main source of energy for cooking and heating. Biomass combustion, particularly in open or poorly ventilated stoves, generates numerous pollutants, including particulate matter, carbon monoxide, and other carcinogens that are potentially harmful to the health of poor adult women and their children (who are carried on their mothers’ backs or play by the fire).

Robert Bailis, Daniel Kammen, and I estimated that, for the year 2000, 350,000 sub-Saharan African children died of lower respiratory infections, and 34,000 adult women died of chronic obstructive pulmonary disease, both attributable to indoor air pollution caused by burning biomass. Worldwide, studies suggest that exposure to indoor air pollution is responsible for over 1.6 million premature deaths a year, and nearly three percent of the global burden of disease. And all these figures may substantially underestimate the true disease burden. Recent evidence suggests an association between exposure to indoor air pollution during pregnancy and low birth weight, which has significant health consequences for adults and children.

Indoor air pollution from solid fuels is now recognized as a major global health concern. For example, solid-fuel use is an indicator for Goal 7 (environmental sustainability) of the Millennium Development Goals.

Exposure to indoor air pollution depends critically on household access to, and choice of, energy technology (that is, the choice of fuel and stove). The greatest risk reductions can be achieved by a complete transition to electricity, or even to direct use of fossil fuels like natural gas and kerosene. (Although the health risks of poisoning or burns from kerosene have not been systematically quantified, they are likely much smaller than the health risks from biomass and coal.) In many developing countries, especially in urban areas, high-income households have transitioned to cleaner fuels. There are, however, important exceptions to this: in China, for example, rapid economic growth and infrastructure expansion have contributed to near-universal access to electricity, yet almost 80 percent of households continue to use biomass or coal as their main energy source for cooking and heating.

 Majid Ezzati

Majid Ezzati is an associate professor of international health at Harvard University’s School of Public Health. His research interests are centered around understanding the determinants of, and risk factors for, health and disease at the population level, especially as they change through technological innovation and technology management.

In fact, for many low-income nations and households, particularly in sub-Saharan Africa, transitioning to clean fuels is not a realistic option for the next 20 to 30 years. One reason is the high up-front costs of the infrastructure needed to generate, process, and deliver clean energy. In Kenya, for example, a gas stove and tank costs around $30–50, while a charcoal stove costs $3–5. Another obstacle is the volatility in petroleum-based fuel prices, caused both by instability in international fuel markets, as well as domestic energy policies.

 Cooking Fire In the meantime, efforts should therefore focus on interventions to modify aspects of the current fuel-stove combinations and energy-use behaviors, and to improve technologies for accessible and clean energy sources. Options include pre-processing biomass and coal to burn more cleanly, and stoves with better ventilation. Separating kitchens or providing additional windows can also reduce pollution exposure. Interventions like these need to take into account local factors like climate and the environment, the purpose of energy use (cooking versus heating), local infrastructure, socioeconomic circumstances, and user behavior.

One particularly important intervention for very low-income societies is greater use of transformed biofuels. Evidence suggests that a substantial portion of the potential health risk reduction from a transition to petroleum-based fossil fuels could still be achieved by shifting toward charcoal. For example, based on current trends in the use of traditional household fuels in sub-Saharan Africa, we projected that, between 2000 and 2030, there would be 8.1 million premature deaths among children and 1.7 million premature deaths among adult women. However, about a million of these deaths could be avoided by a gradual transition to the use of charcoal, while a more rapid transition could nearly triple the numbers of premature deaths avoided.

Using charcoal costs no more to households than burning wood as it avoids the infrastructure requirements of other fossil fuels. Charcoal also has a well-established production and marketing network in many countries and can be more easily scaled up than a transition to fossil fuels.

Greater use of charcoal is not without drawbacks: it would result in much higher emissions of greenhouse gases if the wood is harvested unsustainably and made into charcoal in traditional kilns. And charcoal has implications for forest cover, soil fertility, and biodiversity in ways that have not yet been fully studied. But evidence from Latin America and Asia shows that it is possible to produce charcoal in more environmentally sustainable ways, particularly through changes in land management to ensure sufficient replacement of trees, the use of alternative feedstocks, and the introduction of highly efficient kilns.

Greater use of other transformed biofuels might also produce significant benefits, although these other fuels have received little attention in the health and indoor air pollution literature. Nonetheless, if the technological, funding, and institutional challenges could be met, transitioning to sustainable fuels like charcoal offers a valuable opportunity to promote gender equality and improve environmental sustainability, while also ranking among one of the most cost-effective health interventions in developing countries.

Man Cooking over open fire


Views expressed are those of the author. RFF does not take institutional positions on legislative or policy questions.

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Further Readings:

Bailis, Robert, Majid Ezzati, and Daniel M. Kammen. 2005. Mortality and Greenhouse Gas Impacts of Biomass and Petroleum Energy Futures in Africa. Science 308 (April 1): 98–103.

Ezzati, M. Indoor air pollution and health in developing countries. The Lancet 366(9480), July 9, 2005: 104–106.

Dherani M., D. Pope, M. Mascarenhas, K.R. Smith, M. Weber, N. Bruce. 2008. Indoor air pollution from unprocessed solid fuel use and pneumonia risk in children aged under five years: a systematic review and meta-analysis. Bulletin of the World Health Organization.  May: 86(5):390-398C.

Smith, Kirk R. and Majid Ezzati. 2005. How Environmental Health Risks Change with Development: The Epidemiologic and Environmental Risk Transitions Revisited. Annual Review of Environmental Resources 30: 291-333.

Smith, Kirk R., Sumi Mehta, and Mirjam Maeusezahl-Feuz. 2004. Indoor air pollution from household use of solid fuels. Chapter 18 in Comparative Quantification of Health Risks: Global and Regional Burden of Disease Attribution to Selected Major Risk Factors. Ezzati,M., A.D. Lopez, A. Rodgers, and C.J.L. Murray, editors. World Health Organization.