The Lancet, Volume 377, Issue 9777, Pages 1559 – 1560, 7 May 201
Burning issues: tackling indoor air pollution
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Talha Khan Burki
“The best vaccine for pneumonia is ensuring kids don’t breathe dirty air at home”, asserts Maria Neira, director of WHO’s Public Health and the Environment Department, referring to just one of the many health problems arising from indoor air pollution.
According to WHO, 2 million people die as a result of the smoke generated by open fires or crude stoves within their homes every year. Indoor air pollution has been definitively linked to lung cancer, chronic obstructive pulmonary disease, and pneumonia, the risk of which is doubled by exposure to indoor smoke. More than 900 000 people die from pneumonia caused by indoor air pollution every year. 500 million households worldwide—roughly 3 billion people—rely on solid fuels, such as wood, animal dung, or coal, for cooking and heating. These fuels are usually burned in a rudimentary stove, or in a traditional open fire. It need not be a problem, at least in terms of health. But only assuming the fuel is completely combusted—wood must be dry, and the stove must work efficiently—and there is plenty of ventilation, a spacious chimney, or a sizeable window. In those places where the use of solid fuels prevails, however, these conditions rarely apply, and the consequences can be severe.
Moreover, research into the subject began fairly recently, and is far from comprehensive. The pollutants carried by indoor smoke can fill households to levels well in excess of WHO guidelines for indoor air quality. Emerging evidence implicates indoor smoke in the development of tuberculosis, low birthweight and perinatal mortality, asthma, cataracts, and cardiovascular disease. Some of this might well be taken into account when WHO updates its global burden of disease data later this year. Even the numbers for lung cancer might be underestimated: the percentage refers only to those cases attributable to the burning of coal—predominantly in China—which doubles the risk of lung cancer, but when biomass fuels (wood, for instance) burn, they also emit carcinogens.
Additionally, when family members—usually women—are despatched to gather fuel, they risk snakebite, broken bones, and backache. It can take several hours to accumulate adequate material for a household’s needs, especially if the stove does not work very well, time which cannot be devoted to, say, education.
Those unable to forage enough fuel from the local area can find themselves spending up to a third of their income on purchasing supplies of charcoal. Even worse is the plight of those in war-torn countries such as the Democratic Republic of the Congo. In these places, women gathering bits of wood and agricultural residue are in danger of sexual violence and physical assault. Then there are the stoves themselves, the more rickety of these are prone to toppling over, setting fire to the home or imparting serious burns to those who dwell therein. Those using open fires face similar risks.
The smoke itself contains an array of unpleasant chemicals—carbon monoxide, methane, nitrous oxides, benzene, sulphur and arsenic (from coal), and formaldehyde, to name a few. Cooks—commonly women, perhaps with a youngster strapped to their back—can be exposed to this smoke for 3—7 h a day. Small particles—diameters less than 2·5 μm—seem to be particularly damaging; although the exact mechanism by which they prompt disease is not yet known.
All of which means that for high mortality regions—places such as Afghanistan, where 95% of the population burn solid fuels; India, which has about 400 000 deaths every year as a result of such pollution, and Africa, where pneumonia attributable to cooking smoke kills 0·5 million children younger than 5 years every year—indoor air pollution is the fourth most lethal killer.
Yet, “despite the magnitude of this growing problem” notes WHO “the health impacts of exposure to indoor air pollution have yet to become a central focus of research, development aid, and policy making”. Some of this is down to a lack of awareness—death certificates simply cite “pneumonia” or “bronchitis”, for example, with no mention of what caused the sickness—and the fact that this is a problem of poverty. Then there is the lack of a substantial body of research outlining the effect of indoor air pollution, and the results yielded by interventions. But the past year has had some encouraging advances.
In September, 2010, the UN Foundation launched the Global Alliance for Clean Cook Stoves. “It’s a very important development”, explains Nigel Bruce from the University of Liverpool, UK. “It’s a recognition that this issue needed global coordination.” The Alliance—a public—private initiative—brings together partners from the range of specialties across which the issue of indoor air pollution sprawls. There is public health, of course, but also energy, international development, female empowerment, climate change, technology, and business. “This is potentially one of the most affordable public health issues”, Neira told The Lancet, “because we can link it to the energy and climate change agenda—there’s an exciting mix of benefits”.
“We’re focusing on key areas for engagement to enable the scaling up of clean cook stoves”, Leslie Cordes—interim executive director of the Global Alliance—told The Lancet. The Alliance has set up nine working groups to examine various aspects of the problem—one tackles technology and fuels, another climate research, and another focuses on carbon finance. The health group—led by Nigel Bruce—will identify those areas of research necessary to provide a clearer idea of the damage wrought by indoor pollution. The groups will report back later in the year, outlining priorities and items for early action. The Alliance has set a target of 100 million clean and efficient stoves to be in use by 2020, covering 20% of the affected population. The long-term aim is universal access to such stoves.
Needless to say, a crucial component is raising awareness. In this regard, the Alliance seems to have made a good start, with Hillary Clinton providing high-profile support, the US Government offering US$50 million over the next 5 years and partners such as Shell and Morgan Stanley pledging their support.
There are all kinds of issues at play. In some countries, half of fuel is used to boil water for purification purposes; hence, improvements to water infrastructure would alleviate the problem. Consumers can be encouraged to make small changes—placing lids on pans and drying fuel before use. Building chimneys, cooking outside, and keeping children away from fires would ease the health burden on individual families, although this will not ameliorate the climate effect or harmful emissions to the local community.
The real benefits will be seen by switching to cleaner fuels and cleaner stoves. Improved stoves—those fitted with fans, for example—combust fuel more efficiently, have lower emissions, and require shorter cooking times. Electricity, solar power, or liquid petroleum gas issue none of the noxious pollutants associated with coal and wood. Cordes points out that countries like Senegal have developed the infrastructure for rolling out the use of clean fuels like propane but in most places solid fuels are the only viable option for the population. In which case, encouraging innovative designs to ensure that stoves combust these fuels effectively is likely to form the cornerstone of the Alliance’s strategy. “There’s emerging evidence to suggest that when stoves are working well, they are almost as efficient as burning clean fuels”, says Bruce. Indeed, laboratory studies of some advanced stoves found that the harmful emissions associated with solid fuels were reduced by 98%.
Once the fuels and technology necessary to reduce emissions have been identified, and the potential health benefits proven—and this requires randomised trials and plenty of high-quality evidence—questions of accessibility arise. The Alliance has stated its intention to “develop a thriving global clean cook stove industry”, and is examining financing options that will ensure that those who need the stoves can acquire them.
Finally, there is the issue of donors. The Alliance thinks it will require $250 million, although the picture will become clearer once the working groups return their findings. Cordes draws comparisons with the fight against malaria. “We’re off to the same bold kind of start, and we need the same kind of comprehensive framework and solid foundation.” Neira is optimistic this can be done. She points out that the direct health benefits of clean stoves are a strong incentive for people to change their behaviour. “We agree that we are missing some positive arguments on the climate change agenda”, she says. “The health argument is very powerful and we are not using it enough”.
If pilot projects for clean stoves, such as the national one that is underway in Peru, can be shown to pay dividends, this would be a powerful draw for donors from all sectors. After all, this is a topic that cuts across several of the Millennium Development Goals. “This is real public health—primary prevention”, concludes Neira. “And it could be the public health legacy of the 21st century.”
