Air Quality Index (AQI)
The Air Quality Index (AQI) is a color-coded tool for reporting air quality. It provides simple information on local air quality, the health concerns for different levels of air pollution, and how you can protect your health when pollutants reach unhealthy levels. Measured concentrations of air pollutants are converted to the AQI scale of 0 to 500.
In some areas of Washington, air quality is reported using a similar tool as the AQI, but with different thresholds. It's called the Washington Air Quality Advisory or WAQA, and it was developed by Ecology. Learn more about WAQA here.
Spokane Clean Air reports two AQIs: Current (updated hourly) and Official or Daily (updated at the end of each day).
- The Current Air Quality Index reported here uses an algorithm to weigh the most recent hours of data more heavily. This provides a better representation of current conditions, enabling individuals to make decisions about their outdoor activity level. The Current AQI is calculated differently depending on the leading pollutant, particulate matter (PM) or ozone.
- For PM, current air quality is computed from the most recent 12 hours of PM monitoring data, but the algorithm weighs the most recent hours of data more heavily than an ordinary 12-hour average when pollution levels are changing. This is used in lieu of a 24-hour average PM concentration in the calculation of the official AQI until an entire calendar day of hourly concentrations has been monitored. Learn more about PM
- For ozone, current air quality is computed from the most recent 8-hours of ozone monitoring data, but the algorithm weighs the most recent hours of data more heavily than an 8 hour average when pollutant levels are changing. This is used in lieu of a forward rolling 8-hour average for the calculation of the official AQI until an entire calendar day of hourly data is available. Learn more about ozone
- The Official Air Quality Index for each day is reported to EPA and it is what cooresponds to the health standard, which is a 24-hour standard for PM and an 8-hour standard for ozone. The official AQI is reported each month.
Five year summary 2013-2017.