heat wave is now expanding into the midwest. temperatures and most of the region well above 90. and wildfire smoke from canada is once again making air quality unhelpful. meanwhile, in europe, temperatures continued to score. in greece, and ongoing fire firefight. does not stop. reporter: on the island of evia, a plane had just dropped, burst into flames, killing both air man. as the concrete bakes, the concern grows over an effect known as the urban heat island. so much concrete and asphalt absorbing and remaining heat, it prevents the city from cooling overnight, and has gotten worse over time. in july of 1993, the average low temperature was 81 degrees. ten years later, it was 87. this july? it s 91. there is a race to cool down rescue animals. many treated for burned paws. the heat is particularly hard on