Using the Air Quality Index
The AQI tells us if the air is polluted. It specifically gives us information about how recent levels measured in the air relate to health concerns. The bigger the number, the more air pollution and the higher the risk for health problems.
The AQI measures these air pollutants:
The table shows the possible health effects of air quality at different levels. Each level is a different color with its own set of health problems.
Color (Values)
|
Meaning – What You Can Do
|
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 Green
(0-50)
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Good – It’s a great day to be active outside and a good time to make a plan if worse air quality is in the forecast.
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 Yellow
(51-100)
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Moderate – Some people are especially sensitive to lower levels of particle pollution and should reduce exposure. For example, limit time outside and avoid strenuous outdoor activity. All sensitive groups should watch for symptoms.
|
|
 Orange
(101-150)
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Unhealthy for sensitive groups (USG) – Sensitive groups should take steps to reduce exposure. Limit time outside, avoid strenuous outdoor activity, and follow tips for cleaner indoor air. Everyone should watch for symptoms as a sign to reduce exposure.
|
|
 Red
(151-200)
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Unhealthy – Everyone should reduce exposure. Limit time outside, avoid strenuous outdoor activity, and follow tips for cleaner indoor air.
|
|
 Purple
(201-300)
|
Very unhealthy – Everyone should reduce exposure. Stay inside and filter indoor air to keep it cleaner. Go elsewhere for cleaner air, if needed.
|
|
 Dark red
(301+)
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Hazardous – Everyone should reduce exposure. Stay inside and filter indoor air to keep it cleaner. Go elsewhere for cleaner air, if needed.
|
Washington's Air Monitoring Network
Ecology and other air agencies maintain monitoring stations to measure air pollution in Washington. The map below displays current AQI levels. For a bigger map with more features, go to Washington's Air Monitoring Network map.
Air quality mobile app
Download the air quality mobile app: