The Dangerous Indoors

“Indoor Air Pollution: The Quiet Killer” by Vinod Mishra, Robert D. Retherford, and Kirk R. Smith, in AsiaPacific Issues No. 63 (Oct. 2002), East-West Center, 1601 East-West Rd., Honolulu, Hawaii 96848­–1601.

Indoor air pollution in homes and offices may seem like the last frontier of environmental improvement in the West, but in the poorer nations it is, or ought to be, a frontline health issue. That’s be­cause so many people—nearly half the world’s households—use wood, animal dung, and other unprocessed biomass fuels for their cooking and heating. Long-term exposure to the smoke “contributes to respiratory illness, lung cancer, and blindness,” according to the authors, who are researchers at the East-West Center in Honolulu. Worldwide, according to the World Health Organization, indoor air pollution ranks fifth as a risk factor for ill health—behind malnutrition, AIDS, tobacco use, and poor water and sanitation.

It’s not entirely clear how smoke causes all this harm. It can contain many different potentially harmful compounds, from carbon monoxide to benzo[a]pyrene, which can suppress the immune system. Par­ticulate matter “has been shown to induce a systemic inflammatory response.”

If the precise causes are difficult to specify, the effects are not. In India, where millions are afflicted by tuberculosis, a 1992–93 survey of some 89,000 households found that adults were 2.6 times more likely to suffer from active TB in homes where the cooking was done with wood or dung than in homes where cleaner fuels were used. In India’s rural areas, cooking smoke is blamed for three-fifths of all TB cases. A Mexican study produced similar results.

The India survey also showed that women in households using biomass fuels were 27 percent more likely to be partially or completely blind. In India alone, according to the authors, several hundred thousand women and children die prematurely each year because of indoor air pollution.

Health education and stepped-up efforts to supply rural folk with better cookstoves could reduce the impact of indoor air pollution, the authors say. But ultimately, only economic development—creating, ironically, Western-style outdoor air pollution—will do the trick.