Smoke and Haze vs Cigarettes Calculator
Enter the PM2.5 reading from wildfire smoke, haze or any smoky air, and the hours, and see roughly how many cigarettes’ worth of fine particles that is.
Estimates only. This is general information based on published studies, not health advice.
Hours outside in smoke or haze
Example: 3 hours at 150 µg/m³ is about 0.9 cigarettes, the same dose as about 1.1 hours in a smoky nightclub.
A night in a smoky club
Example: 4 hours in a smoky club is about 3.2 cigarettes, the same dose as 11 hours in haze at 150 µg/m³.
If you are stuck in smoke for weeks. Wildfire smoke and haze reach people in many parts of the world, and weeks of it feel endless. It is normal to worry. People have always spent time in smoky air: in clubs, in smoking rooms and during a haze. The studies on serious lasting harm to the lungs and heart are about years of daily exposure. One study that followed people in Indonesia after the 1997 fires found small average differences in lung function and general health years later, and the differences were smaller after 17 years than after 10. It measured whole populations, so it cannot say what will happen to any one person. A short exposure can cause irritation, a cough or tiredness. People with asthma, heart or lung conditions, young children, older people and pregnant women can be affected sooner, and should follow local health advice. You cannot stop breathing, but you can lower how much you take in, and that is where your control is.
These are estimates, based on the studies linked below. They are information, not health advice. It is a rule of thumb for comparing the amount of fine particles, not a medical measure. Tobacco smoke and haze are different mixtures, and what either does to a person depends on how long and how often, and on their own health. A short, rare exposure is not the same as years of daily exposure. For anything about your own health, ask a doctor.
Sources: Berkeley Earth, Air Pollution and Cigarette Equivalence (22 µg/m³ for 24 hours is about one cigarette). Smoky club level: median PM2.5 in nightclubs in the 2010 Vienna study of 112 venues, 421 µg/m³. Guideline: WHO global air quality guidelines 2021, 15 µg/m³ over 24 hours. After the 1997 haze: Kim and Radoias, Severe Air Pollution Exposure and Long-Term Health Outcomes, Int. J. Environ. Res. Public Health, 2022.
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Wildfire smoke and haze reach people in many parts of the world. Type in the PM2.5 reading from an air quality app or monitor and the number of hours you spend in it. This estimates how many cigarettes’ worth of fine particles that is, and how it compares with the same hours in a smoky nightclub.
It uses a well-known rule of thumb: air with 22 micrograms of PM2.5 per cubic metre, breathed for a full day, is about one cigarette. It is a way to picture the numbers, and the results are estimates, not a measure of anyone’s health.
How it's worked out
- Berkeley Earth's rule of thumb: air with 22 micrograms of PM2.5 per cubic metre, breathed for 24 hours, is about one cigarette.
- So cigarettes are the PM2.5 times the hours, divided by 22 times 24 (528).
- The nightclub comparison uses 421 micrograms per cubic metre, the median reading in nightclubs in a 2010 Vienna study. The hours are the PM2.5 times your hours divided by 421.
3 hours at 150 micrograms is 150 times 3 divided by 528, about 0.9 cigarettes. That is the same fine-particle dose as about 1.1 hours in a smoky nightclub.
Common mistakes
- Typing in an AQI or other index number. Those are index scales. Use the PM2.5 reading in micrograms per cubic metre.
- Reading the result as a health measure. It compares the amount of fine particles only.
- Using one reading for a whole day when the air changes. Use the typical reading for the hours you will be out.
- Treating a short, rare exposure like years of daily exposure. They are not the same.
Questions
Is a long smoke or haze episode dangerous?
Nobody can say for certain what it will mean for one person. The research on serious lasting harm to the lungs and heart is mostly about years of daily exposure. A study that followed Indonesians after the 1997 fires found small average differences in lung function and general health years later, and they were smaller after 17 years than after 10. It measured whole populations, so it cannot predict any one person. A short exposure can cause irritation, a cough or tiredness. People with asthma, heart or lung conditions, young children, older people and pregnant women can be affected sooner, so they should follow local health advice. This tool gives perspective and estimates, not health advice.
Is an hour of haze really the same as smoking?
No. It is a rule of thumb that compares the amount of fine particles, not the effect on a person. Tobacco smoke and haze are different mixtures, and the effects depend on how long and how often you are exposed. This tool gives estimates and general information, not health advice.
What is PM2.5 and where do I find the number?
PM2.5 is the amount of fine particles in the air, measured in micrograms per cubic metre (µg/m³). Air quality apps and monitors show it. If yours shows an index such as the US AQI or a national index, that is a different scale and cannot be typed in here. Look for the PM2.5 figure in µg/m³.
Where do the numbers come from?
The cigarette rule is Berkeley Earth's: 22 µg/m³ for 24 hours is about one cigarette. The smoky club figure is the median nightclub reading, 421 µg/m³, from a 2010 study of 112 venues in Vienna. The guideline is the WHO's 2021 limit of 15 µg/m³ over 24 hours. The links are under the tool.
Why does it say the result is rough above 1,000?
The rule was worked out for ordinary polluted air. At very high levels the straight-line sum is stretched far beyond the data it came from, so treat the number as a loose guide.
Does wearing a mask change the result?
The tool does not take masks, filters or being indoors into account. It uses the reading you type in for the air you are breathing.
Do I need to see a doctor?
This tool cannot say. It is information, not health advice. If you have asthma, a heart or lung condition, are pregnant, or feel unwell in smoky air, ask a doctor.
Between clients. Officially research.