ST. PAUL — The southern half of Minnesota is under an air pollution health advisory until early Sunday morning.

The state Pollution Control Agency said warmer temperatures, moisture and light winds are causing fine particles to form and trapping them near the ground.

The agency said fine-particle levels are near a level considered unhealthy for sensitive groups, such as the elderly, children and people with cardiovascular or respiratory disease.

A cold front is expected to move into Minnesota on Sunday, clearing out the air.