Kirk Smith Brings Global Attention to the Effects of Solid Fuel Use on Health and Climate Change

Professor Kirk Smith pictured with a device his team developed for measuring emissions from indoor smoke. (Photo Peg Skorpinski)

Professor Kalpana Balakrishnan speaking with Secretary Clinton at the Working Womens Forum. (Photo courtesy of Kirk Smith)

Households around the world continue to cook indoors over open fires. (Photo John Minardi)

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In the mid 1980s household biomass fuel use was identified by the United Nations Environment Programme as the most important global occupational health issue.1 In 1992 the World Bank named it one of the four most important environmental hazards in the world.2 Today, despite continuing evidence of damaging effects on health and climate change, three billion people ― almost half of the world's population ― rely on solid fuels for cooking and heating.3

"More people are using solid fuels for cooking than at any other time in history," says Kirk Smith, professor of Global Environmental Health at UC Berkeley. "It's a smaller fraction, but the absolute burden is going up by 20 million more people a year. Put another way, the shift to cleaner fuel is slower than population growth."

Global efforts to reduce the use of inefficient biomass cookstoves gained momentum with a visit on July 20, 2011, by Secretary of State Hillary Rodham Clinton to Chennai, India. Speaking at the Working Women's Forum, Clinton drew attention to the work of UC Berkeley School of Public Health collaborator Kalpana Balakrishnan of Sri Ramachandra University, calling the professor "one of the world's experts on how to make cooking safer for women and children."

Indoor air pollution from cooking and heating with solid fuels accounts for nearly 2 million deaths annually, which is more than the deaths from malaria or tuberculosis.4 Women and children in developing countries are most at risk. Cooking over open fires or with makeshift stoves, they inhale smoke that contains particulate matter up to 20 times higher than the maximum recommended levels by the World Health Organization (20 milligrams per cubic meter).5 Multiple epidemiological studies have linked this exposure to higher rates of acute lower respiratory infection, low birth weight, cancer, blindness and chronic obstructive pulmonary disease.6

In addition to its health damaging effects, solid fuel use has been found to play a role in climate change. "In India, up to 50% of outdoor air pollution may be coming from indoor sources, and 30% in China," reports Smith. Solid fuel smoke contains black carbon, CO2 and methane, pollutants that are active in climate warming, as well as contributing to regional outdoor air pollution.  Black carbon is also implicated in accelerating the melting of mountain glaciers.

Smith has pioneered the study of household air pollution from solid fuel use since the 1980s. "As a doctoral student working with founding COEH director Robert Spear and others, I trained myself to follow the risk. As a physicist, I was working on nuclear energy problems. Soon after graduating, I realized you could have a Chernobyl accident per month and it wouldnt come anything close to [the health effects of] air pollution. We have a million people dying of coal combustion and two million people dying of indoor air pollution that goes on day in, day out. If you want to help real peoples lives, you have to follow the risk."

Smith notes that, "Even with strong evidence, it takes a long time for things to happen." He's seen three big pushes for change in the past: one around  1980, a second in the late 1980s, and now. "The first wave resulted in huge national stove programs in India and several other countries: China introduced 180 million stoves and India introduced approximately 40 million. We now understand only the Chinese program accomplished anything. The others were mixed successes."

When the second round of interest emerged in the late 1980s, stove technology lagged behind the biomedical science. "In retrospect, it was premature then to push a solution nobody had any experience would work," says Smith.

Recently, Secretary Clinton was instrumental to the launch of the Global Alliance for Clean Cookstoves Initiative led by the United Nations Foundation. Actor Julia Roberts joined the Initiative in May as a Global Ambassador to help raise awareness of the organizations mandate to install clean burning stoves in 100 million homes by 2020.7

"Current evidence suggests that you need to achieve very clean combustion to obtain significant improvements -- and that doesn't come about by magic modifications of an existing mud stove," says Smith. "It comes with advanced engineering and materials. You can call a stove 'improved' because you've improved fuel use, but still you may have worsened pollution. Advocacy may still be ahead of implementation science."

Smith, a member of the National Academy of Sciences, leads numerous international efforts to slow climate change and reduce air pollution. He is contributor to the Global Energy Assessment conducted by the International Institute for Applied Systems Analysis (IIASA) in Austria. After years of effort involving a cast of hundreds, the Assessment will report on the future of the worlds energy systems and all its ramifications including climate, health, energy security and the economy.

Another project in which Smith is involved is the Global Burden of Disease and Comparative Risk Assessment organized by a consortium that includes the World Health Organization (WHO). "It calculates the burden of disease from approximately 40 different risk factors globally including household and outdoor air pollution, lead, high cholesterol, unsafe sex, smoking and malnutrition," says Smith.

In addition, Smith is helping to draft the 2012 WHO air quality guidelines and is a lead author for health of the new Intergovernmental Panel on Climate Change (IPCC) effort, Assessment Report 5, to be published in 2014. "One of the biggest single co-benefits between climate and health is household fuels," says Smith.

In September 2011, a team led by Smith is launching  a feasibility study in India to deploy clean stoves to 200 women receiving government-run antenatal care. Eighty percent of poor pregnant women in India participate in the antenatal program, and 96% use solid fuels. Technicians will provide training on how to operate the new stoves and will track its use. They'll also measure air pollution changes and birth outcomes. Smith plans to expand the project into a 10,000 person trial that can form the basis of a national  intervention.

"Studies show a 90-gram difference in birth weight between households who use clean fuel compared to those who don't," says Smith. "If we can show half that gain -- a 45-gram difference in weight -- then the health sector will pay. They are already giving these women benefits in some Indian states worth hundreds of dollars: folic acid and iron pills, nutrition supplements and hygiene education. Women visit clinics a minimum of three times during their pregnancy. Another $50 for an improved stove is not out of hand if we can show the benefit."

Smiths collaborators on the India study include colleagues from the School of Public Health at Columbia University,  his long-term Indian colleagues at Sri Ramachandra University, plus a new group of colleagues from the International Clinical Epidemiology Network, (INCLEN).

1,2,3 Rehfuess EA, Bruce NG and Smith KR. Solid Fuel Use: Health Effect. Nriagu JO (ed.) Encyclopedia of Environmental Health, v 5, pp. 150-161. Burlington: Elsevier, 2011.

4,5 Household Cookstoves, Environment, Health & Climate Change: A New Look at an Old Problem, published online by The World Bank at

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