加拿大野火烟尘污染扩散至美国

Core Viewpoint - Wildfires in Canada since May 26 have led to the spread of smoke and air pollution into several states in the United States, affecting air quality levels [1] Group 1: Air Quality Impact - The smoke from Canadian wildfires has caused air quality deterioration in parts of Minnesota and Wisconsin, with some areas reaching "orange" air quality levels [1] - Most of Wisconsin, along with the upper peninsula of Michigan, eastern Iowa, and northwestern Illinois, have reported "yellow" air quality levels [1] - The U.S. Environmental Protection Agency categorizes air quality into six levels, ranging from green (best) to maroon (worst) [1]