Wildfires burning in Canada were causing unhealthy air quality across parts of North America on Monday. Canadian wildfires burning across northern Manitoba and Saskatchewan are sending smoke through central Canada, the Great Lakes region and the northeastern United States, reducing air quality and visibility in major cities.

Smoke from Canadian wildfires is causing air quality concerns for millions of Americans in the Midwest and Northeast.

Wildfire smoke from California has infiltrated the Las Vegas Valley, creating unhealthy air quality conditions that could impact residents' health, especially those with pre-existing conditions.