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Cleaning Up In the Kitchen: Cleaner Cookstoves

EPA researchers and partners are working to improve cookstoves to protect millions from unhealthy indoor air and help improve the global climate at the same time.

Woman sitting on the dirt floor of her home, filled with smoke from her cookstove.

For roughly half the world's population, the source for both cooking and keeping warm is a simple fire pit surrounded by three large stones arranged to keep a cooking surface above the flames. For the people who rely on them, these simple and inexpensive "solid fuel" cookstoves do the job.

But they are also the world's leading source of environmental death due to indoor air pollution.

A 2009 report Exit EPA Disclaimer by The World Health Organization estimates that the indoor air pollution from typical household cooking fires contributes to nearly 2 million premature deaths annually. "Indoor smoke from solid fuel causes about 21% of lower respiratory infection deaths worldwide, 35% of chronic obstructive pulmonary deaths and about 3% of lung cancer deaths," the report states.

An EPA post doctorial fellow placing materials into a cookstove as part of a study.

EPA recently revamped its stove testing laboratory. Located on EPA's campus in Research Triangle Park, NC, the lab was expanded to include more instrumentation and now has the capability to test stoves with chimney up to five meters tall. Pictured is Seth Ebersviller, USEPA post doctorial fellow.

EPA engineers and scientists are part of an international effort to develop a new generation of clean burning cookstoves that will bring relief across the developing world. Their work has the potential to clear the air in millions of homes and help reduce soot emissions linked to both health impacts and the effects of global climate change. (see below: Black Carbon Research)

Together with the U.S. Department of State and several other federal government and private sector partners, EPA research supports the U.N. Foundation's Global Alliance for Clean Cookstoves, Exit EPA Disclaimer a public-private alliance working to address the problem of polluting cookstoves. As part of that broad effort, EPA researchers have been working with the Global Alliance to test cookstove designs and help guide the development of new, cleaner technologies.

In 2011, EPA researchers conducted an extensive round of cookstove testing. Expanding on previous work (see Better Burning, Better Breathing), they tested 44 combinations of stoves, fuels, and operating conditions for emissions and fuel efficiency.

"You also see the power of the market in the Global Alliance for Clean Cookstoves, which aims to help 100 million families adopt clean cookstoves and fuels by 2020. By supporting consumer research and creating incentives for manufacturers, we're helping to create a market for stoves that people will pay for and use, while at the same time preventing health problems in women and children, and cleaning the air of black soot" - Secretary of State Hillary Rodham Clinton during her remarks at the recent UN Conference on Sustainable Development in Rio De Janeiro

Research results identified designs that offer increased fuel efficiency and lower pollutant emissions, as compared to traditional cooking methods. They found that stoves made from lighter and less dense materials tended to reduce cooking times, thereby increasing fuel efficiency and lowering emissions.

EPA engineers are providing test data and other useful information to the Global Alliance for Clean Cookstoves and others who supply stove technology to developing countries. The engineers and their partners are now evaluating test results to identify the most promising stoves for field trials and to further improve testing methods. What they learn will hopefully lead to cleaner and healthier living conditions for people across the globe.

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Black Carbon Research

"Black Carbon: A solid form of mostly pure carbon that absorbs solar radiation (light) at all wavelengths. Black carbon is the most effective form of particulate matter, by mass, at absorbing solar energy, and is produced by incomplete combustion."(Source: Report to Congress on Black Carbon, EPA 2012.)

The thick, particle-laden smoke emitted from cookstoves is not just a local issue threatening the health of poor families in the developing world. Much of this smoke is composed of "black carbon," a solid form of mostly pure carbon that absorbs solar radiation (light) at all wavelengths.

Black carbon (BC) represents a significant portion of fine particulate matter (PM2.5) air pollution. Numerous EPA and other studies have associated BC with a broad range of adverse health effects, including asthma, heart attacks, low birth weight, and lung cancer.

"Black carbon forms in flames when there is not enough oxygen in the mix and temperatures are not as high as they need to be to ensure that BC is converted to CO2 before it can be emitted into the atmosphere. Older diesel engines, brick kilns, coke ovens, and open biomass combustion that burn fuel under these conditions are major sources of BC pollution around the world. More modern engines and industrial boilers are designed to be cleaner and more efficient by ensuring there is plenty of oxygen, and high temperatures, in the burning zone," explains EPA's Dr. Brooke Hemming.

Dark smoke coming out of an industrial smokestack.

Although modern engines and industrial facilities have helped to greatly reduce black carbon emissions in developed countries like the United States, BC pollution is still a serious concern in the U.S. and across the world.

Black carbon has also been identified as a significant contributor to climate change, particularly in sensitive areas such as the Arctic and the Himalayas where its "albedo" effect—the direct warming that occurs when reflective ice and snow are darkened by with black carbon particles—contributes to earlier spring melting and sea ice decline.

EPA scientists and their partners are conducting research to better understand the effects of black carbon on human health and the environment, both locally and globally. EPA engineer Carlos Nuñez notes "If we want to find the most effective ways to reduce the health and environmental impacts of black carbon, we need to develop the best information we can on its sources, how it behaves in the atmosphere, and how it ultimately affects human health and the environment."

Examples of EPA's efforts are:
  • Nine EPA Science to Achieve Results (STAR) grants totaling more than $6.6 million have been awarded to eight universities to support research analyzing the impacts of black carbon on air and water quality, investigate the behavior of black carbon aerosols in the atmosphere, and develop innovative computer models and other tools to look at black carbon deposits on snow.
  • EPA is collaborating with the University of Michigan on the Near-Road Exposures to Urban Air Pollutants Study (see Can Highways Contribute to Asthma?) evaluating the impact of vehicle emissions, including black carbon, on near-road exposures and asthma.
  • An EPA team is using a sophisticated model called GLIMPSE (Geos-CHEM LIDORT Integrated with MARKAL for the Purpose of Scenario Exploration) to examine the complex scenarios, tradeoffs, and effects of actions taken to reduce black carbon and other atmospheric pollutants.
  • EPA researchers are evaluating different methods for measuring black carbon in controlled and real-world conditions to better understand how black carbon is related to other forms of carbon-based particles and to identify the most effective approaches to black carbon measurement.

Learn More: 

Global Alliance for Clean Cookstoves Exit EPA Disclaimer

Clean Cookstove Research

Igniting Change: A Strategy for Universal Adoption of Clean Cookstoves and Fuels (PDF) (56 pp, 4MB)

EPA Report to Congress on Black Carbon (PDF) (388 pp, 35MB)


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