(Undated) -- Oregon is among four states that reported a new wildfire this week. Arizona, California, New Mexico, and Oregon each reported one new wildfire, bringing the national total up to nearly two dozen as a heat wave slams the Western U.S. Meanwhile, air quality is slowly improving for millions as smoke from Canadian wildfires starts to thin. Despite the improvements, air quality alerts are still in place in over a dozen states in the Northeast from New Hampshire to Wyoming. Since May, nearly two-thousand firefighters have been mobilized to Canada to help as crews battle hundreds of wildfires across the country.