The U.S. Environmental Protection Agency provides information on the heat island effect, its impacts, and the strategies that communities can take to reduce urban temperatures here:
Heat Island Effect | U.S. EPA

Key Issues

  • Image of a person who is sweating Hotter temperatures increase the rate of ground-level ozone formation – air pollution that worsens in Austin’s April – October “Ozone Season.”
  •  During summer months, higher temperatures and associated air pollution can cause discomfort, respiratory difficulties, heat cramps and exhaustion, heat stroke, and even heat-related deaths, particularly in sensitive populations such as children, older adults, and those with existing heart conditions.
  • Hot pavement and rooftop surface temperatures heat stormwater runoff, which raises water temperatures in creeks, rivers, and lakes and can be stressful, even fatal, to aquatic life.
  • Hot weather drives up demand electricity used for cooling, which leads to an increase in emissions from power plants – both air pollutants and greenhouse gases.

Did you know? On warm summer days, surface temperatures in urban areas can be as much as 22° warmer than actual ambient air temperatures. Dark roofs and impervious surfaces such as pavements can be as much as 50–90° hotter than shaded surfaces.