Why are urban heat islands bad?
Heat islands contribute to higher daytime temperatures, reduced nighttime cooling, and higher air-pollution levels. These, in turn, contribute to heat-related deaths and heat-related illnesses such as general discomfort, respiratory difficulties, heat cramps, heat exhaustion, and non-fatal heat stroke.
What is urban heat island phenomenon?
“Urban heat islands” occur when cities replace natural land cover with dense concentrations of pavement, buildings, and other surfaces that absorb and retain heat. This effect increases energy costs (e.g., for air conditioning), air pollution levels, and heat-related illness and mortality.
How does urban heat island effect climate?
With the heat island effect compounding the warming from climate change, cities will likely require more electricity for air conditioning than surrounding areas. For example, based on a 6.3 to 9°F temperature increase, climate change could increase the need for additional generating capacity by roughly 10-20% by 2050.
How do urban heat islands occur?
Heat islands form as a result of several factors: Reduced Natural Landscapes in Urban Areas. Trees, vegetation, and water bodies tend to cool the air by providing shade, transpiring water from plant leaves, and evaporating surface water, respectively.
How is the urban heat island index calculated?
How to Interpret the Urban Heat Island Index. The Index is calculated as a positive temperature differential over time between an urban census tract and nearby upwind rural reference points at a height of two meters above ground level, where people experience heat.
Which is warmer a metropolitan area or an urban heat island?
There’s a science to this temperature contrast, and it’s known as the urban heat island effect. An urban heat island is a metropolitan area that is significantly warmer than its surroundings.
How does heat affect health in urban areas?
The concentration of heat in urban areas creates health risks both because of heat exposure and because of the enhanced formation of air pollutants, especially ozone.
What’s the average temperature in an urban area?
According to the U.S. Environmental Protection Agency, daytime temperatures in urban areas are on average 1-6° F higher than in rural areas, while nighttime temperatures can be as much as 22° F higher as the heat is gradually released from buildings and pavement.