SAN FRANCISCO (KRON) – A Spare the Air Alert that was set to expire Tuesday has now been extended through Thursday, Oct. 8, the Bay Area Air Quality Management District announced.

A Spare the Air Alert is called when air quality is forecast to be unhealthy, or above 100 in the AQI, in any one of the reporting zones.

The unhealthy air is due to smoke from the Glass Fire, which is 50% contained.