Hazy conditions blanketed parts of four U.S. states Monday, as smoke from wildfires in western Canada triggered air quality alerts and warnings.

Canada has 146 active wildfires burning, including dozens in British Columbia and Alberta that are characterized as “out of control,” according to the Canadian Interagency Forest Fire Centre.

In the United States, alerts were in effect in Montana, North Dakota, South Dakota and Minnesota, as winds carried plumes of smoke over the region.

The…