My advisor, writing at CNN:

About the worst thing you can do is stick burning stuff in your mouth. Every year, tobacco kills more than six million people, according to the World health Organization. Including secondhand tobacco smoke affecting non-smokers, it is the chief cause of ill-health (measured as lost years of healthy life) among men globally and for everyone in North America and Western Europe.

The terrible disease burden imposed by tobacco is recognized by most people, but the risk of another form of smoke is also highlighted in the new “Global Burden of Disease” report released last Month in The Lancet – smoke from cooking fires. About 40 percent of the world still cooks with solid fuels, like wood and coal, in simple stoves that release substantial amounts of the same kinds of hazardous chemicals found in tobacco smoke directly into the household environment. Indeed, a typical wood cookfire emits 400 cigarettes worth of smoke an hour.

This “household air pollution” is responsible for about 3.5 million premature deaths each year. Perhaps it is not surprising that the impact on health is so high when one considers that this smoke particularly affects a very vulnerable group – poor women in developing countries.