(KUTV) -- Inversion season is here and that means more Utahns are using the Utah Department of Environmental Quality's (DEQ) color coding system to determine if the air outside is safe.
But is the color coding system even accurate?
The answer is 'sometimes.'
Back in November, 2News noticed that the air outside looked bad but DEQ's air quality app said it was a "green" or "good" day.
Why does this happen?
DEQ's Air Quality Director Bryce Bird says the color bubbles on the app are updated in the morning and the afternoon, and are based on a 24-hour average, rather than real-time information.
That means if you check the app in the morning, the air quality color code has a good chance of being inaccurate.
If you want a more accurate idea of the air quality, you need to focus on the number above them, which shows the particulate in the air.
That number is updated every 15 minutes.
Any Ozone number above 0.071 parts per million is unhealthy for sensitive groups, like children, asthmatics and the elderly.
Any Ozone number above 0.086 parts per million is unhealthy for anyone.
Any Ozone number above 0.201 parts per million is hazardous.
Ozone (O3) is formed when hydrocarbons and nitrogen oxides chemically react in the presence of sunlight and heat. For more information visit Air Pollutants: Ozone.
No word on why the color is updated only twice a day while the particulate number is updated every 15 minutes.