Like a weather forecast, air quality index (AQI) can be forecasted using the (www.airnow.gov).  Yes, not encouraging outdoor activities is correct in days that the air pollution is high, however, providing ways to avoid high air pollution days may be considered.  You can educate individuals before they workout/conduct activities that they should monitor the air quality, time their activities when air quality is good such as before or after traffic hours, avoid smoking environments and >50 foot elevations, and exercise indoors (Laskowski, 2014).  Great post and thanks for sharing!