Convert outdoor PM2.5 into a rough cigarettes-per-day equivalent using a Berkeley Earth rule of thumb.
| Cigarette-eq / day | – |
Use this calculator to turn a PM2.5 reading into a familiar (and imperfect) cigarette-scale comparison, not as a medical diagnosis.
The calculation is: cigarettes per day = PM2.5 (µg/m³) ÷ 22. The 22 µg/m³ per cigarette figure is the Berkeley Earth order-of-magnitude rule of thumb. It compares outdoor fine-particle mass to the particle load of smoking, not the full chemistry of tobacco.
This is not a personal exposure model. Indoor air, time outdoors, age, and other pollutants change the risk picture.
PM2.5 (µg/m³): Outdoor fine-particle concentration. The default 22 is one cigarette-equivalent on this scale.
Cigarette-eq / day: How many cigarettes per day that concentration matches on the Berkeley Earth scale.
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