Are all cigarettes equal? response - Correspondence

Mage raises the issue of exposure to particulate matter from smoking in our study, of indoor smoke and acute respiratory infections in Kenya (1), but the points he raises, although correct, are not applicable in this context. In our study area, smoking was very uncommon. Only a small subset of the group smoked cigarettes (a total of 13 in our study group). Those who did smoke did so very infrequently, often not even on a daily basis, and they often shared their cigarettes because of the cost of cigarettes and because the most common habit in the area is chewing the leaves of the Mirraa plant. Although there are different types of cigarettes and tobacco available in Kenya, we only encountered commercially manufactured cigarettes in our study.

We added 1 mg/[m.sup.3] to the personal total PM exposure for smokers. We obtained this value by assuming a P[M.sub.10] concentration of 400 mg/[m.sup.3] and approximately 4 min of active inhalation. In addition to being a source of particulate matter, smoking was considered as an independent factor in Tables 4 and 5 of our paper (1) to estimate its independent contribution to disease, a more informative source of information. By considering cigarette smoke as a source of PM, we acknowledged this parallel between the two pollutants (while emphasizing the differences in their other properties such as carcinogenesis).

With the uncertainties in assessment of exposure to pollution from cooking and using wide exposure categories, the small number of smokers, and multiple analyses approaches, our findings are not sensitive to the exact level of exposure to PM from smoking.

Majid Ezzati
Resources for the Future
Washington, DC
E-mail: ezzati@rff.org

Daniel M. Kammen
University of California
Berkeley, California

REFERENCES AND NOTES

(1.) Ezzati M, Kammen DM. Quantifying the effects of exposure to indoor air pollution from biomass combustion on acute respiratory infections in developing countries. Environ Health Perspect 109:481-488 (2001).

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