The state Pollution Control Agency has issued an air quality alert for the northern half of Minnesota through noon Sunday, due to smoke from Canadian wildfires. The affected area includes Brainerd, Bemidji, Duluth, Ely, and Moorhead and the tribal nations of Mille Lacs, Fond du Lac, Grand Portage, Leech Lake, and Red Lake. Air pollution can aggravate heart and cardiovascular disease as well as lung diseases like asthma and COPD.