The Louisville Air Pollution Control District has issued an air quality alert for the metro area for Saturday and Sunday.Officials say smoke from grassfires burning in the Fort Knox area and elsewhere have pushed levels of particle pollution into the unhealthy range.Here's more information from the APCD:Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects. Sensitive groups include children, older adults, active adults and anyone with heart and/or lung ailments. Everyone: Cut back or reschedule strenuous outside activities. Sensitive groups: Avoid strenuous outside activities. Help the air on Air Quality Alert days with these simple steps: Share a ride. Delay your mowing. Combine your errands. Avoid idling.