"Hot and Getting Hotter: Heat Islands Cooking U.S. Cities"
"Cities are almost always hotter than the surrounding rural area but global warming takes that heat and makes it worse. In particularly days over 90°F, are associated with dangerous ozone pollution levels that can trigger asthma attacks, heart attacks, and otthe future, this combination of urbanization and climate change could raise urban temperatures to levels that threaten human health, strain energy resources, and compromise economic productivity."