PHOENIX — Environmental regulators have issued an ozone pollution advisory for Thursday in metro Phoenix.

People with respiratory problems are recommended to limit their outdoor activities.

Other recommendations include driving as little as possible, using carpools or public transportation, avoiding drive-thru lines and making sure that containers with household cleaners and other chemicals are sealed to prevent them from evaporating into the air.

The advisory was issued because the area is expected to exceed the federal health standard for air quality.

Ozone forms when vehicle exhaust and chemical solvents combine with heat and sunlight.