“State and local air agencies issue AQI forecasts as a public service to help people plan their outdoor activities. The agencies provide them to EPA, which shares them on the AirNow app and Airnow.gov website. Until now, AirNow users had to remember to check the app or website to see their forecasts; with the updates to the AirNow mobile app, people can opt to be notified when the daily forecast reaches an AQI category of their choosing,” EPA said.

AQI forecasts predict overall air quality for the next day for ground-level ozone and/or particle pollution. Ozone forecasts are based on the 8-hour period with the highest ozone levels; for particle pollution, they predict an average of the next 24 hours. Some agencies provide a forecast for several days at a time.

“The forecasts can be useful planning tools – especially for people who are at risk from ozone or particle pollution. For example, if the next day’s ozone forecast is unhealthy for everyone (Code Red) someone without much flexibility in their schedule may decide to move their outdoor activity indoors for that day. But because air quality can change throughout the day, people with more schedule flexibility can use the forecast as a reminder to check current air quality before heading out for a walk, a run, or even doing strenuous work in the garden,” EPA said.