Soot and Health

The latest New Yorker includes a long article by Burkhard Bilger on engineers trying to build more fuel efficient, less smoky stoves for use by the world's poor. The stove builders are fascinating characters, but what interested me most was the account of how bad for you it is to live in a smoky house:

Clean air, according to the E.P.A., contains less than fifteen micrograms of fine particles per cubic metre. Five times that amount will set off a smoke alarm. Three hundred times as much -- roughly what an open fire produces -- will slowly kill you. Wood smoke, as sweet as it smells, is a caustic swirl of chemical agents, including benzene, butadiene, styrene, formaldehyde, dioxin, and methylene chloride. Every leaf or husk adds its own compunds to the fire, producing a fume so corrosive that it can consume a piece of untreated steel in less than a year. The effect on the body is similar. Indoor smoke kills a million and a half people annually, according to the World Health Organization. It causes or compounds a long list of debilities -- pneumonia, bronchitis, emphysema, cataracts, cancers, heart disease, high blood pressure, and low birth weight -- and has been implicated in a number of others, including tuberculosis, low I.Q., and cleft palate, among other deformities.

The million and a half figure is just an estimate, of course. Other parts of the article (which you can't read without a subscription) describe the miserable pulmonary health of peasants living in smoky houses in ways that make it seem like the toll could be higher. This leaves me wondering about the dramatic decline in death rates that began around 1750 in the western world. That decline puzzles historians, because it comes before there had been many important medical advances or much else we can point to that might help people live longer. Could better stoves have been a big contributor? Were, maybe, Benjamin Franklin and his fellow stove tinkerers (stoves were a focus of much effort and ingenuity at the time) the unsung heroes of falling death rates? Our ancestors used to spend five months a year or so cooped up in smoky houses, huts, or yurts, with effects on their lungs and hearts that must have been terrible. Was central heating as important a contributor to long modern lives as municipal sewers and the smallpox vaccine?