WISCONSIN — An air quality advisory from the Wisconsin Department of Natural Resources, labeled "unhealthy for sensitive groups," was set to expire overnight into Thursday across Polk, St. Croix, Pierce, Barron, Dunn, Pepin, Chippewa and Eau Claire counties.

“The weather pattern in the Eau Claire area has been the main driver for this event,” said Craig Czarnecki, outreach coordinator for the DNR’s air management programs. “The pollution is kind of staying trapped at the surface.”

Czarnecki said a lack of wind there over the past few days, along with moisture from melting snow and the snow itself keeping temperatures colder at ground level, combined to form a fine particulate matter pollution — PM2.5 — and triggered the advisory. 

“People who would be most impacted would be the elderly, young children or people with asthma, heart or lung disease,” Czarnecki added.

Watch the full interview above.