But what it is, exactly?
The Air Quality Index is a scale used for daily reporting of how clean or polluted the air is, and what health effects might be of concern.
The AQI focuses on what you might experience if exposed within a few hours or days after breathing polluted air.
The Environmental Protection Agency calculates the AQI using 5 major air pollutants regulated by the Clean Air Act:
- Ground-level ozone
- Particle pollution (also known as particle matter)
- Carbon monoxide
- Sulfur Dioxide
- Nitrogen Dioxide
AQI BY THE NUMBERS
The AQI runs from 0 to 500. The higher the AQI value, the greater the level of air pollution and the greater the health concern.
The index is divided into six categories, each corresponding to a different level of health concern.
An AQI of over 100 triggers an alert for vulnerable groups.
Levels over 300 signal a health emergency and everyone is more likely to be affected.
Full breakdown:
Good: 0 to 50
Moderate: 51 to 100
Sensitive Groups: 101 to 150
Unhealthy: 151 to 200
Very Unhealthy: 201 to 300
Hazardous: 301+
Learn more about the index from the EPA at AirNow.gov.
6abc Air Quality Tracker