"Breathing in the Canadian wildfires smoke cannot be the new normal," said Candice Miller, Macomb County public works commissioner.

Environment Canada says smoke from forest fires is causing reduced visibility and poor air quality that is expected to persist into Sunday for some areas.

Smoke from wildfires blazing across Canada is once again wafting over huge portions of the Midwest and worsening air quality, with conditions particularly bad on August 1 in Minnesota, Iowa and Illinois.