Air Quality Index Guide: What Should You Do in Each Level?

Particle pollution is one of the most common pollutants, and often it is not clear what we can or should do at each air quality index level. Basically, an air quality forecast doesn't mean much if you don't understand how to use it.

In today's blog, we're sharing the six air quality index levels, from good to hazardous. 

Air Quality Index Levels

Air quality index  At-risk population Actions
Good  (0-50) No risk Enjoy the outdoors!
Moderate (51-100) People unusually sensitive to particle pollution

Unusually sensitive people: It is advisable to reduce heavy physical activity and monitor symptoms. 

Overall population: Outdoor activities are still a good idea!

Unhealthy for sensitive groups (101-150)

Older adults

Children and teenagers

People with heart or lung disease

Sensitive groups: Outdoor physical activity is allowed. Take more breaks and reduce the outdoor time. Monitor symptoms. 

People with asthma: Follow your asthma action plan. Keep quick relief medicine handy.

People with heart diseases: Look out for palpitations, shortness of breath, or unusual fatigue. If they are present, contact your health provider, they may indicate a serious problem.

Unhealthy (151-200) Everyone

Sensitive groups: Avoid heavy physical activity. It is best to move activities indoors or reschedule.

Overall population: Outdoor physical activity is allowed. Take more breaks and reduce the outdoor time if possible. Monitor symptoms. 

Very unhealthy (201-300) Everyone

Sensitive groups: Avoid all physical activity outdoors and change them to an indoor setting. Consider rescheduling to a time when air quality is better.

Overall population: Avoid physical activity. Consider moving activities indoors. 

Hazardous (301-500) Everyone Everyone: Remain indoors and keep activity levels low. Follow tips for keeping particle levels low indoors. 


Worried About Air Quality?

Monitor the Particulate Matter levels around the world with our free, real-time PurpleAir Map. or join PurpleAir's mission to make air quality data accessible to everyone by investing in an air quality monitor for your home. 

Together, we can be informed and make changes in our daily habits and the community to improve air quality.


EPA. (2015). Air Quality Guide for particle pollution - EPA. Retrieved May 10, 2022, from