Canadian wildfire smoke brought numerous air quality alerts to the Northeast on Aug. 4, including in multiple North Jersey counties.

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.

An air quality alert is in effect for all of Massachusetts today due to smoke from Canadian wildfires, and it could be the worst air quality day the Boston area has seen all year. The Massachusetts Department of Environmental Protection issued an alert for "fine particulates" in the air until midnight.