Today is an air quality red alert day for Salt Lake, Davis, Utah and Weber counties.

Cache County air quality is moderate, making it a yellow air quality day.

In the four red-alert counties, the air is unhealthy for sensitive people, those with respiratory or heart disease, the elderly and children. Those groups should reduce prolonged or heavy exertion outdoors.

The Utah Department of Environmental Quality asks residents to drive as little as possible during red and yellow days because cars contribute significantly to the area's air pollution.