Burke, Catawba, Alexander and Caldwell counties are all under a red alert today for air quality.
The alert was issued by the state Department of Environmental Quality and was in response to what the state says are rapidly rising levels of fine particle pollution attributed to smoke from active wildfires in Canada.
As the smoke continues to build into the state, the DEQ website noted, high levels of fine particles are expected to mix near ground level.
"PM2.5 is comprised of particles smaller than the width of a human hair," the website stated. "These particles can reach deep in the lungs and aggravate asthma and other lung conditions and have been linked to heart conditions."
Code Red on the air quality index represents unhealthy air quality for everyone, the website said. The state asked local residents to consider limiting prolonged or heavy exertion outdoors. Anyone sensitive to air pollution, including people with asthma, should avoid outdoor exertion altogether.