By Susan P. Williams
Washington Post Staff Writer
Monday, May 23, 2005
In the highlands of Ethiopia, the temperature dips to an average 37 degrees at night. A typical family's one-room house has no chimney, and the stove consists of three stones supporting a pot over an open wood fire. The mother fixes dinner as her toddlers edge closer, trying to stay warm in the swirling smoke.
And as they do, the air they breathe may be killing them.
A recent study estimated that in the next 25 years, 10 million women and children in sub-Saharan Africa will die prematurely from the smoke produced by the most basic and comforting of sources: the family cookstove.
"The actual physical exposure to smoke is off the scale, as far as our standards are concerned," Kim Mulholland, a clinical pediatrician at the London School of Hygiene and Tropical Medicine, said in a recent telephone interview.
The chemical compounds and minute particles that make up wood smoke affect growing and full-grown lungs in different, but equally dangerous, ways. Among children younger than 5, indoor smoke makes them much more susceptible to respiratory infections; in adults, the result is chronic obstructive pulmonary disease.
The lower respiratory infections in children usually end up as pneumonia, Mulholland said. Worldwide, such infections are responsible for 19 percent of deaths in children younger than 5, the World Health Organization (WHO) reported recently.
Public health workers have been trying for decades to reduce the toll of cooking fires by introducing less-polluting stoves. But a recent study by U.S. scientists concluded that in sub-Saharan Africa, where 80 percent of families depend on wood for fuel, the best approach must address energy and environmental issues, as well as the impact on women's and children's lungs.
The smoke from cooking fires hangs indoors because few stoves in sub-Saharan Africa vent to the outside, said Majid Ezzati, one of the authors of the study published last month in the journal Science. Chimneys are impractical because often "the roofs are made of grass, and there's the possibility of fire." In the semi-nomadic communities, he said, houses are constructed quickly and cheaply. Even if a family has the money for chimney materials, it is unlikely to invest in a home it plans to leave soon.
Because of the time a mother spends over the cookstove, her exposure to smoke is substantially greater than her children's, Mulholland said. He noted that research has shown that carbon monoxide, one of the compounds in wood smoke, reduces a pregnant woman's placental blood flow, and she is more likely to bear an underweight child.
Although chimneys would improve indoor air quality, they would just move the problem outdoors. By 2050, the study's authors estimated, smoke from wood fires will release at least 7 billion tons of greenhouse gases into the environment each year. That is about 6 percent of the total expected to be produced from the African continent.
Today, Africa produces only about 5 percent of the world's greenhouse gases, said Daniel M. Kammen of the University of California at Berkeley, another of the study's authors. But it will probably produce much more, he wrote in an e-mail, because "after decades of trailing Asia, Africa now has the fastest rate of urbanization in the world," and city dwellers use more energy.
The best-case scenario would be for Africans to switch from "biomass" fuels, such as wood, charcoal or dung, to fossil fuels, such as kerosene or liquid propane gas, for cooking, said Robert Bailis, a graduate student at UC-Berkeley and the study's principal author.
"If you promote fuel switching, then not only are you going to have health benefits, you are going to have these global benefits," Bailis said.
He acknowledged that talk of nonrenewable oil-based fuels "raises a greenhouse-gas flag," because emissions from fossil fuels are responsible for the majority of greenhouse gases believed to contribute to global warming.
But more immediate obstacles prevent Africans from seeking alternative cooking fuels.
Africa's limited infrastructure for distilling and transporting fossil fuels is one of them, the study found.
But Robert J. van der Plas, an energy consultant in the Netherlands, disagreed. In a review of the Bailis team's study, he wrote that "kerosene is available in every nook and cranny of the urban and rural environment" in Africa.
The real problem, he noted in a study of energy use in Chad published earlier this year, is money. "A household would have to at least double its cooking fuel budget to switch to modern fuels, and there are not many households willing -- or able -- to do this."
As long as a switch to petroleum-based fuels is out of reach economically, Bailis and his team believe that in sub-Saharan Africa, the next best approach would be to switch to charcoal. It offers twice as much energy per unit of weight, Bailis said. It resists rot, termites will not eat it, "and compared to wood, it's fairly clean-burning."
Depending on how quickly the transition took place, the researchers said, using charcoal could prevent 1 million to 2.8 million premature deaths.
Switching from wood to charcoal, however, raises another set of issues.
To make charcoal, one or two men usually cut down a tree, light it, cover it with dirt and wait a few days for the end product -- a method that creates significant air pollution. However, if you "increase the efficiency of charcoal-making, you can improve health without having large environmental consequences," said Ezzati, an assistant professor at Harvard's School of Public Health.
Bailis also acknowledged that wider use of charcoal would do little to reduce deforestation. "We want the people who make these policies . . . to think about what kind of land-management policies can be put in place . . . for sustainable energy," he said.
WHO points out that reducing indoor air pollution would make progress toward at least half of the millennium development goals for improving the health and welfare of poor people everywhere, which each United Nations member pledged to reach by 2015. The less time women spend collecting fuel, the more time they have for education or careers, thus fighting poverty and promoting gender equality. The less smoke children breathe, the more likely they are to live to adulthood.
Success could raise the pall from millions.