As of Saturday afternoon, Logan, Utah, had the highest air quality index in the United States at 180, tying with Waltham, Massachusetts for the worst air quality in the U.S. According to IQAir, Utah cities made up seven of the top 10 cities with the worst air quality in the U.S. on Saturday.

According to research done by Berkeley Earth and an Air Quality Index to Cigarettes Calculator, breathing Utah air for 24 hours was equivalent to smoking up to five cigarettes in some areas. How many cigarettes worth of bad air did you breathe?

The numbers: Utah’s air quality has been moderate to unhealthy this week, according to IQAir. The city with the worst air quality on Saturday was Logan, whose AQI matched up to cities such as Wuhan, China, and Kabul, Afghanistan, which sat at #6 and #7 respectively on the world air quality charts on Saturday.

As far as major cities go, Salt Lake City ranked #17 in the world for worst air quality. However, if smaller cities were included in the rankings, it’s likely that Utah would have ranked among the top 5.

Utah did however have some of the worst air quality in the county this weekend, according to IQAir’s U.S. air quality ranking.

U.S. air quality ranks, Saturday, Feb. 4:

  1. Logan, Utah: 180 AQI.
  2. Waltham, Massachusetts: 180.
  3. Thermal, California: 175.
  4. Mendon, Utah: 172.
  5. Smithfield, Utah: 172.
  6. Hidden Meadows California: 168.
  7. Providence, Utah: 165.
  8. Perry, Utah: 158.
  9. Brigham City, Utah: 155.
  10. Millcreek, Utah: 154.

How many cigarettes? With an AQI of 180 on Saturday, residents of Logan would have breathed about 5.27 cigarettes worth of bad air within 24 hours, the AQI to cigarettes calculator estimated. Residents of the Salt Lake Valley would have breathed around 3 cigarettes worth of bad air in 24 hours at 152 AQI, according to the calculator.

Dangers of breathing bad air: According to the World Health Organization, breathing polluted air for extended amounts of time can lead to severe health risks, especially in people who are already sick.

National Geographic says that health effects from breathing polluted air over long periods of time can include pneumonia, bronchitis, dizziness, nausea or even more severe effects such as heart and lung disease.

Methodology: Researchers at Berkeley stated that small particulate matter of pollution can work its way into the bloodstream and lungs. Prolonged exposure to highly polluted air could pose health risks, especially to people who have certain health risks.

  • The formula for this particular study states that breathing in 22 micrograms of air pollutants per cubic meter of air is equivalent to smoking one cigarette. The AQI to cigarettes calculator uses this same formula.

Limitations: The AQI to cigarettes calculator website states that there are potential limitations to the calculator. The website for the calculator states that the data could be off because not all pollutants are equally dangerous. The creator of the calculator states that it is created to observe the impact of pollutants on human health, not to calculate the number of particles inhaled.

How to stay safe when the air is bad: Even when the air quality outside is bad, there are ways that you can stay safe, The New York Times reported.

  • Stay indoors if you can, keeping doors and windows closed.
  • Run your air conditioner constantly, closing the fresh air intake. It could also be beneficial to install an air filter.
  • Use portable air cleaners.
  • Avoid frying and cooking food indoors that could cause smoke.
  • Avoid intense outdoor activity, including exercise.