Berkeley Earth's rule of thumb — 22 µg/m³ of PM2.5 for a day ≈ one cigarette — turns any
air-quality reading into a number you can feel. Enter a ZIP or city for today's figure, then explore
how the math scales across the whole index below.
Today, by location
Live PM2.5 for a US ZIP or any city worldwide, converted to cigarettes per day.
or
0.0cigarettes / day
PM2.5
US AQI
Per week
Per year
The full curve · AQI 50–500
Time axis
AQI
PM2.5
1 cigarette in
1 pack (20) in
1 cigarette 1 pack (20 cigarettes) reference: 1 day / 1 week / 30 days