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LETTERS and an annual loss of over 38.5 million pollution and the other causes of global ill disability-adjusted life-years.5 Compare this health are less important, but because out- Air pollution and health: indoor air with the 800 000 deaths and 4.6 million lost door air pollution was the topic of the life-years resulting from outdoor air pollution Thorax journal article by Ko et al2 about pollution in the developing world cited in Thurston’s editorial. which I was writing. Thorax: first published as on 28 February 2008. Downloaded from is the real key to reducing the Thurston is correct to call scientists and However, since the issue has been raised, it is physicians to act on climate change and important for the reader to note that the health burden of ill health health. Industrialised countries currently top impact numbers cited by Fullerton and Semple the table of carbon dioxide emissions per for indoor air pollution are highly uncertain. We welcome the editorial by Thurston capita (with the USA ranked first and the UK Indeed, a recent review concluded that one of highlighting the effects of air pollution on 6 1 ranked eighth). Paradoxically, however, they the key research questions in this field is: health. Air pollution has been shown to suffer least from the effects of polluted air. ‘‘What is the quantitative relationship have an important effect on the mortality of Therefore, while it is important to investigate between exposure to indoor air pollution and those with pre-existing respiratory and 2 the effects of outdoor air quality on health, the incidence of disease (ie, the exposure– cardiovascular conditions. we think that there is a clear and urgent need response relationship)?’’.3 Even the reference Outdoor sources of air pollution are impor- to expend at least as much effort on that Fullerton and Semple rely upon4 tant contributors to indoor air pollution attempting to understand and control indoor acknowledges that: ‘‘It is questionable, concentrations, particularly in developed air pollution in the developing world. however, whether exposure–response countries. However, global human exposure relationships derived from pollutant-based to particulate matter (PM)—in terms of the 1 2 D G Fullerton, S Semple investigations are applicable to populations number of people, exposure intensity and 1 Pulmonary Immunology, Liverpool School of Tropical exposed to indoor air pollution in rural areas of time spent exposed in various microenviron- Medicine, Liverpool, UK; 2 Department of Environmental and developing countries, since most pollutant- ments—varies greatly in different parts of the Occupational Medicine, University of Aberdeen, Aberdeen, UK based epidemiological studies were conducted world. In industrialised countries, only 1% of Correspondence to: Dr D G Fullerton, Pulmonary outdoors in urban areas of developed countries. global PM exposure occurs in outdoor envir- Immunology, Liverpool School of Tropical Medicine, Liverpool Potential problems include differences in onments with a further 9% occurring indoors L3 5QA, UK; [email protected] pollutant mix and composition, exposure (fig 1). In the developing world, 14% occurs patterns and levels, and population outdoors while 76% of human exposure to 3 characteristics. The chemical pollutants PM occurs in indoor environments. produced by burning solid fuels, for example, As a result of energy poverty, almost one- REFERENCES are different from those produced by burning half of the world population burns organic 1. Thurston G. Air pollution, human health, climate fossil fuels.’’ In fact, to address just this need for http://thorax.bmj.com/ material such as wood, dung or charcoal for change and you. Thorax 2007;62:747–8. better estimates for use by policy makers, there household cooking, heating and lighting. This 2. Brunekreef B, Holgate ST. Air pollution and health. is a commendable new major effort to improve form of energy is associated with very high Lancet 2002;360:1233–42. 3. Smith KR. Indoor air pollution in developing countries: and update such estimates being initiated levels of indoor PM concentrations (perhaps growing evidence of its role in the global disease (http://www.globalburden.org). Thus, given 2–3 orders of magnitude higher than those burden. In: Ikeda K, Iwata T, eds. Indoor air ’96. the large uncertainties surrounding present found outdoors) and an increased incidence of Published by the Organizing Committee of the 7th such global estimates, using them to rank the acute lower respiratory infections, tuberculo- International Conference on Indoor Air Quality and importance of various causes of ill health seems sis and chronic obstructive pulmonary disease. climate, Japan, SEEC ISHIBASHI Inc, 1996. 4. Smith KR. Women’s work: the kitchen kills more than the inappropriate at this time.

Women and children, who spend much of on September 29, 2021 by guest. Protected copyright. sword. In: Jacquette JS, Summerfield G, eds. Women their time indoors cooking and preparing food, In conclusion, I would agree with and gender equity in development theory and practice. Fullerton and Semple that indoor air pollu- are disproportionately affected by indoor air Durham, NC: Duke University Press, 2006:202–15. 4 tion is also a concern regarding both human pollution. The World Health Organization 5. Desai MA, Mehta S, Smith KR. Indoor smoke from lists indoor air pollution from burning solid solid fuels: assessing the environmental burden of health effects and climate change, but one fuels as one of the top 10 global health risks, disease at national and local levels. WHO that needs—and deserves—much more responsible for 1.6 million premature deaths Environmental Burden of Disease Series, No 4. Geneva: extensive direct research regarding the size World Health Organization, 2004. per year, 2.7% of the global burden of disease of its potential for human health effects as a 6. Marlan G, Boden TA, Andres RJ. Global, regional, and function of both fuel type and population. national CO2 emissions. In: Trends: a compendium of data on global change. Oak Ridge, Tennessee: Carbon G D Thurston Dioxide Information Analysis Center, Oak Ridge National Laboratory, US Department of Energy, 2000. Correspondence to: Dr G D Thurston, New York University School of Medicine, New York, NY 10918, USA; Thurston@ env.med.nyu.edu Author’s reply I agree with Fullerton and Semple that indoor air pollution is another major envir- REFERENCES onmental concern—in addition to outdoor 1. World Health Organization. The World Health Report air pollution—that affects both human 2002: reducing risks, promoting healthy life. Geneva: health and climate change. But calling World Health Organization, 2002. indoor air pollution the ‘‘real key to reducing 2. Ko FWS, Tam W, Wong TW, et al. Temporal relationship between air pollutants and hospital the burden of ill health’’ carries their point admissions for chronic obstructive pulmonary disease too far. While these are both important in Hong Kong. Thorax, 2007;62:780–5. factors, there are also many other causes of 3. Ezzati M, Kammen DM. The health impacts of ill health throughout the world besides exposure to indoor air pollution from solid fuels in indoor and outdoor air pollution, including developing countries: knowledge, gaps, and data malnutrition, obesity, sexual and reproduc- needs. Environ Health Perspect 2002;110:1057–68. tive health risks, tobacco use, unsafe water, 4. Desai MA, Mehta S, Smith KR. Indoor smoke from 1 solid fuels: assessing the environmental burden of and the list goes on from there. disease at national and local levels. Annex 3. WHO Figure 1 Total global exposure to particulate In my editorial I focused especially on Environmental Burden of Disease Series, No 4. Geneva, matter. Data from Smith.3 outdoor air pollution, not because indoor air World Health Organization, 2004.

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