Washington Air Quality Advisory

The Washington Air Quality Advisory (WAQA) is an index for reporting air quality. We created the WAQA information tool to advise you about air quality levels. When there is too much fine particle pollution in the air, your health could be at risk.

What WAQA is used for

Ecology developed WAQA to provide accurate information about the health risks of fine particle pollution (PM2.5). Scientific studies show that levels of PM2.5 in the air previously thought to be safe can cause illness and death. In fact, scientists have not been able to identify a safe level of PM2.5 pollution.

WAQA tells us if the air is polluted. It also explains the possible health effects associated with varying levels of pollution. WAQA focuses on health effects you may experience from breathing polluted air and suggests ways to protect yourself from air pollution.

WAQA measures these air pollutants:

Air quality monitoring mobile app

Our quality monitoring data is also available in a free, mobile-friendly application:

Apple iOS: Air Quality WA - iOS

Google Android: Air Quality WA - Android


The Washington Air Quality Advisory (WAQA) is similar to EPA's national information tool, the Air Quality Index (AQI). Both use color-coded categories to show when air quality ranges from good to hazardous. The difference is that WAQA is based on lower levels of fine particle pollution than the federal AQI. This allows us to alert you earlier to protect your health.

Smoke and dust are some examples of fine particles. Studies show that levels of particles in the air that we previously thought were safe can cause illness and death.

Comparison of the WAQA and AQI health-risk levels

Color – Category Index Value WAQA AQI
  Concentration of fine particles (PM2.5) (µg/m3)

Green dot Green – Good

0–50 0–12.0


Yellow dot Yellow – Moderate

51–100 12.1–20.4


Orange dot Orange – Unhealthy for Sensitive Groups

101–150 20.5–35.4


Red dot Red – Unhealthy

151–200 35.5–80.4


Purple dot Purple – Very Unhealthy

201–300 80.5–150.4


Dark Red dot Dark red – Hazardous


more than 150.4


Go to the Washington Air Quality Monitoring Network map for the full interactive version. Colors on the map refer to the levels of air pollution and related health warnings.