Better Burning, Better Breathing: Cleaner Stoves
EPA researchers are testing performance and emissions of solid-fuel cook stoves.
For most Americans, cooking on an open fire is a novelty enjoyed outdoors a few times a year. But for about half the world's population, it is a daily necessity. Instead of cooking with gas, oil, or electricity, they burn wood, dung, coal, or other solid fuels. For this population, a kitchen is primarily a place to build a fire.
According to the World Health Organization (WHO), an estimated 1.5 million people die prematurely each year due to exposure to smoke and other pollutants from the household use of solid fuels, while millions more suffer respiratory illness. The effect is greater on women and children because they tend to spend more time near cook stoves.
In a 2002 report, WHO listed indoor smoke from solid fuels among the top 10 risks to human health. "Day in and day out, and for hours at a time, women and their small children breathe in amounts of smoke equivalent to consuming two packs of cigarettes per day," WHO reported in the 2006 report Fuel for Life: Household Energy and Health.
As greenhouse gas emissions have increased, the smoke from kitchens in the developing world has escalated from a local to a worldwide threat. The average cooking fire produces about as much carbon dioxide as a car, and produces more soot, also known as black carbon. Reducing these emissions may be among the fastest, cheapest ways to fight global climate change.
Bringing better solid-fuel cook stoves to the 3 billion people who rely on them can improve human health, reduce cutting down forests for firewood, and decrease the emission of greenhouse gases and black carbon. As stated in the New York Times article Third-World Stove Soot Is Target in Climate Fight: "While carbon dioxide may be the No. 1 contributor to rising global temperatures, scientists say, black carbon has emerged as an important No. 2, with recent studies estimating that it is responsible for 18 percent of the planet's warming, compared with 40 percent for carbon dioxide."
Researchers from the U.S. Environmental Protection Agency (EPA) tested a number of household cook stove and fuel combinations for performance and air pollution emissions. The work was done to support the Partnership for Clean Indoor Air (PCIA), an association of more than 370 organizations contributing their resources and expertise to reducing smoke exposure from cooking and heating practices. PCIA was launched at the World Summit on Sustainable Development in Johannesburg, 2002.
The objectives of the EPA study were to:
- See if some cook stoves have improved fuel efficiency and lower pollutant emissions compared with the traditional "three-stone fire," (three stones placed around a fire to hold up a pot).
- Provide useful cook stove performance and emissions information to PCIA partners and others supplying stove technology to developing countries.
- Compare test results using the Water Boiling Test protocol with those of a PCIA partner, Aprovecho Research Center in Cottage Grove, Oregon.
Research results from the study, presented in the paper "Solid-fuel household cook stoves: Characterization of performance and emissions" (Biomass and Bioenergy Journal, Volume 33, Issue 2, February 2009) showed that some stoves currently used in the field offer the benefits of improved fuel efficiency and lower pollutant emissions compared with traditional cooking methods. Stoves with lighter, less dense materials exposed to the heat of the fire tended to cook faster with better fuel efficiency and lower pollutant emissions.
The study provided an independent evaluation of 14 stove/fuel combinations with an emphasis on modern cook stoves designed to reduce harmful emissions and improve fuel efficiency. It illustrated the importance of testing stoves, and presented useful information for improving the design of stoves. Test results using the latest stove technology had not been reported in the peer-reviewed scientific literature before. The study also shows that stove-testing results can be replicated between laboratories, and offers recommendations for improving the ability to replicate results. Publishing the results has been useful to the more than 300 partners in PCIA who design and promote new stove technology.
Now a more comprehensive, solid-fuel cook stove study is underway. Newer stove designs are being tested, and more air pollutants are being measured. EPA researchers are continuing to measure emissions of air pollutants that affect human health, including those that affect global climate.