A year of this air, in packs
25 packs of 20. Every year. Nobody lit a single one.
Cleaner air in Americas
Same region, fewer cigarettes. The index is about air, not real estate — but if you're choosing where to live, start here.
Cleaner air is the easy part. The hard part is a job and a home. Two free tools, built by the same small team as this index:
Same team, separate products. Nobody pays to appear in this ranking.
How the number is made
The rule
Physicists Richard and Elizabeth Muller (Berkeley Earth) compared the particle mass a smoker inhales with the mass you inhale from city air. One cigarette works out to about 22 µg/m³ sustained over a day. It is a mass equivalence, not a claim that smog and smoke are chemically identical.
The data
Annual mean PM2.5 per city, on the scale used by IQAir's World Air Quality Report and the WHO ambient air database. The WHO annual guideline is 5 µg/m³ — about 0.23 cigarettes a day. Only 14% of measured cities met it in 2025. Values here are rounded estimates on that scale and will be replaced city by city with the official 2025 figures.
What it misses
Tobacco smoke carries carcinogens city air mostly doesn't, and a smoker's dose comes in minutes, not hours. Averages also hide winter spikes: Delhi in November runs several times its yearly mean. Treat this as a sense of scale, not a diagnosis.
Babies and children
Kids breathe far more air for their size. Per kilo of body weight, a baby inhales about 3× and a school-age child about 2× what an adult does (US EPA Exposure Factors Handbook). The baby and child numbers apply that factor.
Corrections
Figures are rounded and some cities are represented by their nearest monitored station. If you have better data for a city, send it — the number matters more than the ranking.