IT IS a lethal agent that kills more children under the age of five than malaria, measles or AIDS. In fact, across the developing world it is the fourth biggest cause of death and disease, period. Yet the chances are that you will never have heard of the problem.
Stumped? Here鈥檚 a clue. Next time you boil the kettle or put a meal in the microwave, reflect on the fact that more than a third of humanity 鈥� that鈥檚 around 2.4 billion people 鈥� have to cook every day on traditional stoves that burn wood, crop residues or dung. And what do such stoves give off? That鈥檚 right, smoke. Staggering amounts of the stuff.
In fact, research by the UN Development Programme indicates that people who cook on traditional stoves end up inhaling the equivalent of two cigarette packets鈥� worth of toxic chemicals each day. This level of ingestion helps to explain why cooking smoke is thought to claim the lives of 1.6 million people every year, most of them women and small children.
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It鈥檚 a shockingly high figure. And yet there really is no great mystery to it. Cooking smoke, just like the lethal emissions of a cigarette, is a potent cocktail of carbon monoxide, particulates, hydrocarbons and nitrogen oxides, as well as carcinogenic organics such as formaldehyde and benzene. These damage the immune system and the ability of the upper airways to filter out particles. Hence children exposed to cooking smoke are two to three times as likely to contract an acute lower respiratory infection such as pneumonia as those who breathe clean air, and women are up to four times as likely to suffer from a long-term obstructive pulmonary diseases such as chronic bronchitis. Studies also indicate that cooking smoke is a risk factor for asthma, tuberculosis, cataracts and giving birth to babies of low weight.
What is surprising 鈥� and shocking 鈥� is the lack of any concerted political will or coordinated international effort to tackle the problem. OK, so there is no simple quick fix. The traditional biomass stove, consisting of not much more than three stones on the floor, has changed little since the Stone Age, and asking people to alter something as fundamental as the way they cook is not a step to be taken lightly. Think how difficult it would be to persuade the average westerner to give up their gas stove, grill and electric toaster and use only, say, a microwave.
Yet there are measures that development agencies and governments could and should be taking. The first step is to make people aware that their cooking habits could be killing them and their children. Next, and most obviously, offer some alternatives. The most effective way of reducing smoke in the home is to stop burning biomass and use a cleaner fuel such as liquid petroleum gas or kerosene. Hearing this, many environmentalists concerned about greenhouse gases will rush to tie themselves in moral knots over the wider consequences of shifting billions of people off biomass burning, which is in principle carbon neutral, and on to fossil fuels. In fact, greenhouse warriors can relax: the vast majority of people in developing countries simply could not afford to cook with fossil fuels.
What is within their reach, however, is the next best thing: a stove with a chimney that takes the smoke out of the room. For people living in houses that cannot support a chimney, free-standing smoke hoods that take the smoke up into the roof away from the cook can work just as well.
The Intermediate Technology Development Group (ITDG), a non-government organisation based in the UK, has been testing these approaches with rural communities in Kenya and has found that both can reduce indoor air pollution by an impressive 80 per cent.
And they needn鈥檛 cost the earth. The ITDG is calling on the UN to draw up an action plan that matches the international response to AIDS, dirty water and malaria. It estimates that $2.5 billion a year for the next 12 years would provide more than 2 billion people with a healthy indoor environment. This amounts to little more than a dollar a person per year.
The European Commission has recently introduced a new safety standard for pollution with PM10s 鈥� particles less than 10 micrometres in diameter. This says that levels of PM10s, averaged over 24 hours, should not exceed 50 micrograms per cubic metre more than 35 times a year. At present women cooking over fires in developing countries have little choice but to breathe in air in which PM10 levels average 10 times that limit, and can reach 1000 times the limit.
This is a choking level of pollution more than 10 times that on the worst days of London鈥檚 鈥済reat smog鈥� of December 1952, which killed an estimated 4000 people. The London smog was a key factor in bringing about the UK鈥檚 Clean Air Act, which controlled domestic smoke emissions for the first time. Surely the time has come for a global clean air act.