What is Thermal Pollution?

Thermal pollution is going to be a factor of increased importance due to climate change as it encompasses everything from region down to the density of buildings and even further to the materiality of the environment. These range of factors are captured within the concept of the Urban Heat Island, a metropolitan area (source). Heat stress is associated with elevated heart rates which can lead to heat stroke, cardiovascular issues, and a loss of sodium and potassium which is all of particular risk for those with weakened hearts, often the elderly (source). Urban heat islands generally have reduced air and water quality due to the industrialisation, transport, and density, so it is normal for heat pollution to rise with air pollution.

HOW THERMAL POLLUTION IS AN URBAN PLANNING PROBLEM

The core problem of heat in cities is identified through the Urban Heat Island (UHI) effect; where a metropolitan area is a lot warmer than the rural areas surrounding it due to human activities. The main cause of the UHI effect is from the modification of land surfaces. Waste heat generated by energy usage is a secondary contributor. The UHI decreases air quality by increasing the production of pollutants such as ozone, and decreases water quality as warmer waters flow into area streams and put stress on their ecosystems.

Concrete and black asphalt in particular are two problematic materials as they retain heat. Dark-coloured asphalt positively bakes when temperatures rise, absorbing 80% to 95% of the sun’s rays. On a sweltering summer day when the mercury reaches 100 degrees Fahrenheit, the surface temperature of L.A.’s roads can climb to as much as 50 degrees higher. The U.S. city of Los Angeles has sought to paint roads white as a way to repel heat. Recommended further reading is ‘Dangerous Heat, Unequal Consequences’