albedo

Urban heat island (UHI) phenomenon has been observed in many populated cities located in cold regions (e.g., Montreal in Canada) during summer. One of the well-known strategies to mitigate the temperature rise of urban areas is increasing their albedo. Roofs cover about 25% of urban areas and increasing their reflectivity would have significant effect on the total energy budget of a city. Changing the surface energy budget can directly affect the air temperature near ground and the vertical wind speed.

The mitigation of the heat island effect can be achieved by the use of cool materials that arecharacterized by high solar reflectance and infrared emittance values. Several types of cool coatings,both commercially available and prototype ones have been tested. Their spectral reflectance, infraredemittance and surface temperature measurements reveal that these materials can be classified ascool materials with the ability to maintain lower surface temperatures. Cool materials can be used onbuildings (roofs and walls) and other surfaces of the urban environment.