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Feature: Ceramic indoor cookstoves may not cut air pollution

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Low-cost, locally-produced ceramic cookstoves may produce less smoke than traditional indoor 3-stone firepits, but they don't drastically reduce indoor air pollution or the risk of pneumonia in young children, a year-long observational study by researchers working in rural Kenya has revealed.

The new peer-reviewed study published on Thursday shows that new cookstoves for the developing world may not have the impact that public health experts and advocates have hoped for, a dramatic reduction in the incidence of respiratory infections among some of the world's poorest children.

"Despite requiring less fuel, these stoves may not be efficient enough. The belief is that you need much more efficiency, maybe a reduction of 50 percent or more, to really observe the health benefits," said Robert Quick, a researcher in the Division of Waterborne, Foodborne, and Enteric Diseases at the U.S. Centers for Disease Control and Prevention.

For one year, Quick and his colleagues followed the health of children under three years of age in 20 villages in the Nyando District of Western Kenya, which were already participating in a water quality study.

The cases of pneumonia were diagnosed by fieldworkers trained to recognize familiar signs of the illness, such as a cough combined with a specific rapid breathing rate, but the cases were not confirmed by x-rays or other objective tests. The stoves study also was not a randomized controlled trial, Quick noted.

According to the study, women who used the ceramic stoves (called "upesi jiko", which is Swahili for "quick stove") reported less smoke in their homes, along with fewer stinging eyes and runny noses.

However, the study found that even though there were fewer respiratory symptoms, these stoves only reduced air pollution by 13 percent and there was no significant difference in pneumonia among children under three years of age in these homes when compared to those in homes with 3-stone firepits.

"This support of improved cookstoves is exactly what we need to be seeing on this front, but we also need to be sure that the improved cookstoves are actually improving the air quality in a way that reduces health risks too," Quick said.

Since 2008, households in the district have been able to purchase locally produced upesi jiko stoves, sold at a cost of about 2-3 U.S. dollars.

The researchers looked at how rates of cough, pneumonia, and severe pneumonia differed among the infants, and whether these differences were related to upesi jiko or traditional firepit cooking.

The locally-made ceramic cookstoves in the Kenyan study are built into a matrix of mud and sand in the homes and draw air in through a small hole in the side to deliver heat up to a burner surface.

The upesi jiko stoves are somewhat more efficient than 3-stone firepits and require less wood or other fuel for cooking.

Experts have hoped to reduce women's and children's exposure to the small particles and toxic gases coming from indoor cooking with unprocessed fuel such as wood, charcoal or peat.

One study has found this exposure nearly doubled the risk of pneumonia in children through inflammation of the airways and lungs.

Pneumonia is the leading cause of death for children under 5 years of age in developing countries, with nearly 70 percent of these 1.2 million deaths occurring in Southeast Asia and sub- Saharan Africa.

Women and their young children bear the brunt of health problems caused by cooking indoors, in inadequately vented spaces, over open fires fueled by unprocessed wood, charcoal or other biomass.

The findings are the first to examine the health impacts of ceramic cookstoves that do not vent smoke to the outside of the house, according to researchers at the CDC, Emory University School of Medicine, Kenya's Safe Water and AIDS Project, and the Kenya Medical Research Institute (KEMRI).

This study follows findings reported in late 2011 from a randomized controlled trial in Guatemalan children (RESPIRE) that suggested that the use of improved cookstoves (with chimneys that vented smoke outside the home) did not significantly reduce the risk of physician-diagnosed pneumonia.

The researchers point to the need for the global clean cookstoves movement to invest in developing and distributing the right stoves.

Research has found household air pollution can increase the risk of pneumonia-a 2008 study found that exposure to this type of pollution from burning solid fuel nearly doubled the risk of pneumonia in young children. Very small particles and toxic gases in indoor smoke can inflame the airways and lungs.

"There is currently a lot of research activity into the design of cleaner burning cookstoves, including by the KEMRI and the Centers for Disease Control and Prevention," Quick said. Cleaner burning cookstoves are thought to be one way to reduce harmful household air pollution.

The Global Alliance for Clean Cookstoves, one of the most prominent public-private partnerships in this area of public health, has raised 114 million dollars in its goal to put 100 million new stoves into households in the developing world by 2020.

The Global Alliance for Clean Cookstoves and the World Health Organization are also evaluating six other cookstove technologies in a separate study, to find out which designs produce the least pollution, Quick said.

"Even though a stove might appear to be burning efficiently, you don't necessarily remove the key exposures associated with pneumonia," he added.

"There is a real demand for upesi jiko stoves and I think that just reflects that the reality of using a three-stone firepit is not very pleasant," said Quick. "If you've ever been in any of these huts while people are cooking, there's choking smoke in the household."

Along with reducing smoke, the upesi jiko cooked faster and gave women more space for food preparation.

Quick said that health researchers and global partnerships should pay more attention to these kinds of details as they strive to find ways to reduce household air pollution. "The more we are meeting the actual demands of these mothers, the better we will do. "

"This research on cookstoves illustrates that the approach to improving children's health must employ strategies that take a holistic view of the child, one that includes the home," said David H. Walker, MD, the new president of the American Society of Tropical Medicine and Hygiene and chair of the department of pathology at the University of Texas Medical Branch in Galveston.

He said data from this and further studies will help aid programs make evidence-based decisions as they determine where to allocate their increasingly scarce funds.

"In the end, cost may be still a significant factor in adopting cleaner cookstoves. The upesi jiko stoves "are relatively cheap, around three dollars, but even this small cost is beyond the reach of many people who typically earn 1-2 dollars per day," Quick said.

According to the study, despite the active marketing and availability of this stove, most households didn't have one. Endi