Smoke from Canadian wildfires is once again blanketing the skies over Chicago and Minneapolis, causing a severe drop in air quality. The upper Midwest and Northeast regions are experiencing some of the worst air quality levels in the world, prompting widespread health concerns and advisories.

Air quality alerts are in effect for over 100 million people across seven states, warning residents of the dangers of prolonged exposure to the smoky conditions. The haze has significantly reduced visibility, creating hazardous conditions for drivers and outdoor activities. Health officials are urging vulnerable populations, including children, the elderly, and individuals with respiratory conditions, to stay indoors and limit physical exertion.

The unhealthy air is expected to persist through Friday, with a gradual improvement anticipated by Saturday as the smoke plume shifts further south. However, even with the expected shift, areas downwind may still experience elevated levels of air pollution.

The Canadian wildfires, which have been raging for weeks, have released massive amounts of particulate matter into the atmosphere. This particulate matter, known as PM2.5, is particularly harmful because it can penetrate deep into the lungs and bloodstream, leading to a range of health problems, including respiratory irritation, asthma exacerbation, and cardiovascular issues.

Residents are advised to monitor local air quality reports and follow the guidance of health officials. Using air purifiers, keeping windows closed, and wearing N95 masks when outdoors can help reduce exposure to the harmful effects of the smoke. The situation highlights the far-reaching impacts of wildfires and the importance of addressing climate change to mitigate future events.