On the Road to Beating the Heat

Heat islands — typically referred to as urban heat islands (UHI) — are urban and suburban areas with significantly higher temperatures than surrounding rural areas. UHIs can impact energy use, environmental issues, and public health.

Many cities and suburbs lack abundant green spaces and trees, which naturally cool the air and ground through evapotranspiration (water absorbed through the ground and emitted as vapor), provide shade, and capture dioxide. Many building materials, such as asphalt, concrete, and dark rooftops, trap and retain heat. As cities grow vertically with tall buildings, air flow is limited and heat is kept close to the ground, causing UHI effects even at night. Densely populated and densely constructed cities also emit more waste heat from vehicles, factories, and construction, worsening the effect.

Yes. Although suburbs may grow horizontally with fewer high-rise buildings and may have more parks, these areas still have features that induce heat islands. Large parking lots, wide roads, energy-intensive businesses, large homes cooled by air conditioning, and building and roofing materials that retain heat can all contribute to heat islands.

Mean radiant temperature measures both outdoor air temperature (OAT) and surrounding surface temperatures to provide an accurate assessment of how heat feels and is perceived, similar to "wind chill factor." It is useful for measuring urban heat islands, where MRT is typically higher than nearby rural areas even when the OAT is similar, due to surfaces that trap heat, higher density, and fewer green spaces.

UHIs affect air and water quality, increase peak energy demand in summer, and can lead to serious health concerns and death. Urban heat disproportionately affects vulnerable populations in dense areas, including lower-income people who do not have air conditioning, senior citizens, and unhoused people. For example, a report found that in New York City between 2010-2020, more than 100 residents died of heat stress and another 2% of deaths by natural causes were considered to be exacerbated by summer heat. Daily life impacts include higher utility bills in summer, rolling blackouts, inability for children to engage in healthy outdoor play, and difficult conditions for construction, utility, and other outdoor workers.

Urban heat islands lead to higher energy usage and greenhouse gas emissions as people and businesses increase their use of air conditioning and fans. Without carbon dioxide-absorbing vegetation, more emissions enter the atmosphere.

Reducing surface temperatures and mean radiant temperature can lead to less energy use in the summer. Planting more trees and increasing vegetation cover, green spaces, and rooftop gardens helps absorb carbon dioxide, as well as protect against erosion and reduce stormwater runoff. Using surface materials like CoolSeal, which incorporates recycled materials in its formula and is free of polymers, hazardous volatiles, and carcinogenic additives, provides additional environmental benefits.

CoolSeal reflects 30% more sunlight and lowers surface temperatures by 10-16℉, compared to uncoated asphalt. It can lower surface temperatures by up to 20℉ as compared to black-coat asphalt. It also lowers subsurface temperatures by nearly 5℉, resulting in long-lasting surfaces that reduce maintenance needs and save on costs.