Air Pollution and Cigarette Equivalence

The Air Quality Index / Cigarette equivalence is based on the increased number of deaths from each.

One cigarette is equivalent to an air pollution of 22 μg/m3 for one day. Thus, an AQI of Particles (PM2.5) of 160 (today in San Francisco) is equal to 160 / 22 = about 7 cigarettes.