One of the key sources of heat is the urban heat island phenomenon which traps heat in thermal mass like concrete and black roads which absorb, store and then re-emit this heat to the urban air at night.
The urban heat island phenomenon has far-reaching environmental sustainability and human livability implications. Temperatures of urban air domes can range up to 10-16C (50-60F) warmer than the surrounding countryside.
Infra-red thermal image of Tokyo. Urban Climatology and Urban Thermal Climates, photo by M. Roth, National University of Singapore
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Infra-red thermal image of heat emitted in city street, 9pm. Photo authors.
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Impacts:
- Urban climate impact: intensification of extreme urban climatic events
- Health consequences: increased heat-wave mortality, air-pollution intensification
- Public safety consequences: public-realm avoidance-behavior, leading to increased crime opportunity
- Energy consumption consequences: increased consumption of energy for air-conditioning of
- buildings, unsustainable peak electricity demand, brown-outs
- Global warming impact: urban thermal emissions are trapped by greenhouse gas emissions (CO ) thus contributing to climate-change
Health consequences of heat. Heat Index Chart. www.tvweather.com
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Heat x Ozone Pollution Intensity, Stone B., Urban Heat and Air Pollution, Journal of the American Planning Association, Vol 71(1) p13, 2005.
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