Elevated smog levels have prompted authorities to issue an air quality advisory for the Portland and Vancouver metro areas.

Oregon and Washington officials expect ozone pollution to hit levels Monday afternoon that could be unhealthy for people including children, pregnant women, seniors and those with heart disease or respiratory conditions.

Authorities recommend people in sensitive groups limit outdoor activity when pollution levels are elevated.

The Oregon Department of Environmental Quality also urges people to limit pollution-causing activities such as unnecessary engine idling and mowing grass during the advisory, which is expected to last until Tuesday morning.

Smog levels should improve overnight and through the remainder of the week, according to the agency.

Oregon residents can monitor air quality where they live using an interactive online map.