What Is the Air Quality Index?

We thought we'd take a break from our regularly scheduled program to talk about something a little different today: the Air Quality Index. While we'd normally use this blog space to talk in depth about our product offerings and deals, sometimes it's good to spice it up — as long as we're still learning something, that is! This blog post will examine the official Air Quality Index, including how it's calculated and used. We hope you can learn all about how the Environmental Protection Agency (EPA) attempts to calculate pollution and inform the public about toxic air levels. Keep in mind that different countries have different standards for the Air Quality Index and calculate their own indices differently from the United States. This blog post will focus on the Air Quality Index in regard to the United States only.

What Is the Air Quality Index (AQI)?

The air quality index is a number calculated by governmental agencies (typically the Environmental Protection Agency in the U.S.) to tell the general public about the quality of the outside air, including how polluted it currently is, or how polluted it will be in the near future. When smog and pollution build up, the air quality index rises, and the index lets the general population know exactly how polluted the air is. The index lets us know how unsafe the air is to breathe.


Here are some things you should know about the pollution levels of the Air Quality Index:

  • An index below 100 is considered healthy. The EPA considers the air to be satisfactory. Factories and other pollution-releasing entities should strive to abide by AQI rules below 100.
  • With an index of 101 to 150, the air is considered to be on the brink of being unhealthy. Those who are extra sensitive to pollutants can be negatively affected.
  • When the index reaches above 150, it is considered unhealthy for everyone. This means that you should stay inside as much as possible.
  • From 201 to 300, the AQI is considered very unhealthy. You should avoid going outside.
  • Finally, from 301 to 500, the AQI is considered extremely hazardous. This means the air quality has reached a level that can kill you. At this level, it is an emergency situation.

What Pollutants Does the EPA Measure in the Air Quality Index?

The EPA takes five major pollutants into account when measuring the air quality index. These five are the ground-level ozone, particle matter pollution, carbon monoxide, sulfur dioxide, and nitrogen dioxide. According to the EPA, the ground-level ozone and particle matter pollution are the two pollutants that are the most troublesome in the United States.

How Is the AQI Calculated?

The concentration of pollution is calculated by using advanced technology obtained by an air monitor model. The concentration is calculated against time to determine the dosage of the pollution level. This model was originally determined by what is called epidemiological research — research that determines the distribution and effects of pollution.

We hope you feel a little more informed about the Air Quality Index! Stay tuned for more blog posts!