Uploaded on 2016-08-18 by Ali El Messaoudi

More heat can increase ozone air pollution. All 51 cities with adequate data showed a statistically significant correlation between higher daily summer temperatures and bad air quality (as measured by ground-level ozone concentrations). Temperatures are being forced higher by increasing urbanization and manmade global warming, which could undermine the hard-won improvements in air quality and public health made over the past few decades. In two thirds of the cities analyzed (41 of 60), urbanization and climate change appear to be combining to increase summer heat faster than climate change alone is raising regional temperatures. In three quarters (45 of 60) of cities examined, urbanized areas are warming faster than adjacent rural locations. The top 10 cities with the most intense summer urban heat islands (average daily urban-rural temperature differences) over the past 10 years are: Las Vegas (7.3°F) Albuquerque (5.9°F Denver (4.9°F) Portland (4.8°F) Louisville (4.8°F) Washington, D.C. (4.7°F) Kansas City (4.6°F) Columbus (4.4°F) Minneapolis (4.3°F) Seattle (4.1°F) On average across all 60 cities, urban summer temperatures were 2.4°F hotter than rural temperatures. Urban heat islands are even more intense at night. Over the past 10 years, average summer overnight temperatures were more than 4°F hotter in cities than surrounding rural areas.