OFFICE LOCATION:
Butte County Air Quality Management District
629 Entler Avenue, Suite 15
Chico, CA 95928
(530) 332-9400

Air Quality Index Chart

Breath Well Mobile App for real time ozone and fine particulate levels in your immediate area or throughout California.

Users of the Breathe Well mobile website can check air quality before they go outside or check air pollution levels in places they plan to visit. The easy-to-use Breathe Well mobile website draws on one of the most sophisticated and comprehensive air monitoring networks in the world made possible by the significant investment by the ARB and local air districts in California. The site can access hour-by-hour averages of data that is relayed from about 200 monitors statewide.

Real-time information will help people better manage the timing of their outdoor activities, and help teachers and parents of children with asthma know when it’s safe to play outside or participate in sporting activities. Real-time levels give an accurate indication of the air quality before that level may be reached. The hour-by-hour information can also be compared to other air quality indicators that predict the highest levels of pollution expected for that day, which typically are not reached until the afternoon.

The Breathe Well website can be accessed from any PC or mobile device with Chrome, Internet Explorer or Firefox or other Internet browsers. Breathe Well’s features include:

  • At-a-glance levels of ozone and fine particle pollution (PM2.5) linked to the location of a smartphone or tablet;
  • The ability to set the air pollution readout for your current location — or one of about 150 locations; and
  • Maps that pinpoint the location of nearby air quality monitors.


Breathe Well won “Best Mobile App” at the Mobile Government 2013 conference held at the Sacramento Convention Center last March.

Exposure to ground-level ozone and PM2.5 (particles 2.5 micrometers in diameter or smaller) are the two pollutants that most affect the air we breathe. High levels of ozone and fine particles can reduce lung function, making it more difficult to breathe, and can cause or worsen asthma and other cardiovascular disease. Ozone is a gas that forms when sunlight combines with emissions from traffic and other human activities. Particle pollution may be emitted directly into the air or can form in the air from other emissions.

Receive Air Quality Alerts to your email box To receive the daily air quality forecast via email, page or text message subscribe online. Find out the current and forecast air quality conditions for sites in California. California Air Quality Conditions and Forecasts

Clean Air Primer
The Clean Air Primer is organized into easy learning modules for use with different abilities and interest levels and makes use of the latest, up-to-date techniques in media delivery. Explore, see and learn about what's in the air.

Mini video on YouTube about the Air Quality Index. The video describes all aspects of the AQI in less than 60 seconds.

Be Aware of Your Air!

AQI Health Categories Ozone Particulate Matter
0 to 50 Good None None
51 to 100 Moderate Unusually sensitive people should consider limiting prolonged outdoor exertion. Unusually sensitive people should consider reducing prolonged or heavy exertion.
101 to 150 Unhealthy for Sensitive Group Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion. People with heart or lung disease, older adults and children should reduce prolonged or heavy exertion.
151 to 200 Unhealthy Active children and adults, and people with respiratory disease, such as asthma, should avoid prolonged outdoor exertion; everyone else, especially children should limit prolonged outdoor exertion. People with heart or lung disease, older adults and children should avoid prolonged exertion. Everyone else should reduce prolonged or heavy exertion.
201 to 300 Very Unhealthy Active children and adults, and people with respiratory disease, such as asthma, should avoid all outdoor exertion; everyone else, especially children should limit outdoor exertion. People with heart or lung disease, older adults and children should avoid all physical activity outdoors. Everyone else should avoid prolonged or heavy exertion.
>300 Hazardous People with heart or lung disease, older adults, and children should remain indoors and keep activity levels low. Everyone else should avoid all physical activity outdoors. People with heart or lung disease, older adults, and children should remain indoors and keep activity levels low. Everyone else should avoid all physical activity outdoors.

Users of the Breathe Well mobile website can check air quality before they go outside or check air pollution levels in places they plan to visit. The easy-to-use Breathe Well mobile website draws on one of the most sophisticated and comprehensive air monitoring networks in the world made possible by the significant investment by the ARB and local air districts in California. The site can access hour-by-hour averages of data that is relayed from about 200 monitors statewide.

Real-time information will help people better manage the timing of their outdoor activities, and help teachers and parents of children with asthma know when it’s safe to play outside or participate in sporting activities. Real-time levels give an accurate indication of the air quality before that level may be reached. The hour-by-hour information can also be compared to other air quality indicators that predict the highest levels of pollution expected for that day, which typically are not reached until the afternoon.

The Breathe Well website can be accessed from any PC or mobile device with Chrome, Internet Explorer or Firefox or other Internet browsers. Breathe Well’s features include:

  • At-a-glance levels of ozone and fine particle pollution (PM2.5) linked to the location of a smartphone or tablet;
  • The ability to set the air pollution readout for your current location — or one of about 150 locations; and
  • Maps that pinpoint the location of nearby air quality monitors.


Breathe Well won “Best Mobile App” at the Mobile Government 2013 conference held at the Sacramento Convention Center last March.

Exposure to ground-level ozone and PM2.5 (particles 2.5 micrometers in diameter or smaller) are the two pollutants that most affect the air we breathe. High levels of ozone and fine particles can reduce lung function, making it more difficult to breathe, and can cause or worsen asthma and other cardiovascular disease. Ozone is a gas that forms when sunlight combines with emissions from traffic and other human activities. Particle pollution may be emitted directly into the air or can form in the air from other emissions.