Graphic of Air Quality Alert LevelsIf you’ve lived in the United States for any substantial period of time, you’ve probably seen an air quality alert warning come across on your local TV or Radio station.

But, do you know what an air quality alert actually means?

Every day, the Environmental Protection Agency (EPA) monitors the air quality throughout the U.S. and reports it online at This data is then used to alert you on how dangerous the air around you can be to your health.

To make it easy for you to determine how bad the air quality is in your location, the EPA developed a color coded system that relates to pollution levels.

  • Green – means the air is good quality
  • Yellow – means that the level is moderate quality and starting to get polluted
  • Orange – means that the air is very dangerous to breathe, especially for people with respiratory issues, including asthma and the elderly
  • Red – means the air quality is becoming dangers for everyone
  • Purple – means that the air quality is extremely hazardous for all groups and it’s best to stay in doors as much as possible

There are two things that contribute to harmful air pollution and impact the level of an air quality alert.

  • Ground-level Ozone – High levels are the most frequent cause of air quality alerts. It’s created by vehicle exhaust emissions and industrial fumes, as well as chemical reaction of Nitrogen and Volatile Organic Compounds (VOC) in the presence of sunlight.
  • Particulate Matter – This consists of pollutants such as soot, ash, smoke and dust. Often it’s caused by chemical processes or the burning of fossil fuels.

An Orange or red alert day are usually the most common color codes you’ll see in your local area. Often a green or yellow alert is not reported since it doesn’t make much in the way of news. A purple alert is very rare, but has occurred in extreme environmental pollution cases.

Here are just a few recent reports of bad air quality levels around the U.S.

If you’re located in an area that has an orange, red or purple alert, the best thing you can do is to stay inside and shut all windows and doors. This will help prevent any airborne pollution from entering into this area.

If you’re especially sensitive to airborne contaminants, or just want to ensure that air within your home is not polluted, adding an air purifier can help. To find out which air cleaning device is best suited for your needs, take a look at the many free air purifier guides on our website.