Air Quality Policy.
1 - There are a lot of different websites (and they report different numbers) but I use the IQAir.com or PurpleAir.com to monitor air quality index (AQI).
2 - All practices and games will be canceled by the league if the anticipated AQI is at 151 or higher (red or higher). If the anticipated AQI is between 101-150 (orange), you may have a light practice but sensitive individuals should sit out. Games may or may not be canceled if the anticipated AQI is between 101-150 (orange).