Smoke from hundreds of Canadian wildfires is drifting south and east, pushing air-quality readings into unhealthy ranges across large sections of the United States and Canada. The U.S. National Weather Service has extended an air-quality advisory for all of Wisconsin through at least noon Sunday, warning conditions will remain "Unhealthy for Sensitive Groups" to "Unhealthy". Similar alerts cover Iowa, Minnesota, Michigan, eastern Nebraska and parts of Indiana and Illinois. Air-quality monitors placed parts of Minnesota in the red zone, with Air Quality Index values exceeding 150 on Saturday, among the worst readings globally, according to IQAir. North of the border, Environment Canada issued special air-quality statements stretching from eastern British Columbia to western Quebec. The advisory now includes the Greater Toronto Area, where forecasters say smoke may linger through the weekend and visibility could deteriorate without notice. Officials are urging residents—especially children, older adults and people with heart or lung disease—to limit outdoor activity and keep windows closed. The smoke comes as British Columbia confronts 146 active wildfires. Environment Canada placed much of the province’s Interior under severe thunderstorm watches on Saturday, warning that lightning, strong winds and hail could ignite new blazes or hamper firefighting. With weather systems expected to shift only gradually, forecasters say elevated pollution levels could persist in some regions into early next week.