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Understanding the Air Quality Index

July 8, 2014
A city is engulfed in smog.

Air quality is an important part of our daily lives, but it's often overlooked because we don’t really understand what the charts and graphs are trying to tell us. AirNow is a division of the Environmental Protection Agency that offers valuable information regarding the pollution level of air all across the United States.

The Air Quality Index (AQI) is similar to a measuring stick that runs from 0 to 500. The higher the AQI number is, the more dangerous it is to breathe the air. The numeric values are separated into 6 color-coded categories that designates increasingly dangerous levels. Listed below are the different categories and their corresponding numbers on the AQI:

  • “Good” is 0-50. Air quality poses no risk!
  • “Moderate” is 51-100. Air quality isn’t bad, but people who are very sensitive to pollutants may experience respiratory problems.

  • “Unhealthy for Sensitive Groups” is 101-150. Most people won’t be negatively affected by the air quality, but older individuals and children may have trouble breathing.

  • “Unhealthy” is 151-200. Everyone will likely experience negative side effects.

  • “Very Unhealthy” is 201-300. This would trigger a health alert for everyone.

  • “Hazardous” is anything above 300. This is an emergency level where side effects of the air pollution become very serious. Stay indoors if possible!

The AirNow website has a national summary of the AQI listed by state, or you can type in your ZIP code to a menu at the top of the page and get a personalized report. Keep an eye on the AQI and enjoy your outdoor adventures!

About the Author

A Georgia native, Rachael Wheeler works as a Web Support Specialist for GeorgiaGov. She writes about a variety of current topics relevant to the Georgia government.