PORTLAND, Ore. (KOIN) — The Oregon Department of Environmental Quality issued an air quality advisory Thursday for Salem and Oregon City, citing increased levels of smog.

Officials say ozone pollution will likely reach an unhealthy level for sensitive groups, such as children, seniors, pregnant women and those with heart disease or breathing problems.

The advisory will be in effect until Thursday evening.

Between now and then, officials say residents in the Salem and Oregon City areas should limit activities that cause pollution during a heat wave. This includes driving less, avoiding idling when it’s unnecessary, postponing mowing the lawn or using a leaf blower and postponing using paint and aerosol spray.

Air quality reportedly worsens as temperatures rise and there is increased exposure to sunlight.

Officials say those experiencing severe irritation to the eyes, nose and lungs should reach out to their doctor.