AUSTIN (KXAN) – Urban heat islands occur when there’s a high concentration of materials such as concrete, asphalt and steel. These materials absorb more heat energy from the sun instead of reflecting it causing temperatures in cities to be warmer than their surrounding areas.
Higher temperatures in cities can lead to increases in pollution, higher energy bills and negatively effect human health because of exhaustion, heat-related mortality, and respiratory problems.
Using technology to address the “Urban Heat Island”
Which is why the folks over at Pavement Technology, Inc. are currently testing a product in cities across the Southeast that is proving to curb the effects of the urban heat island.
Their solution comes in the form of a sprayable titanium dioxide called Plus TI.
Ken Holton of Pavement Technology Inc. explains, “So the titanium dioxide is very faceted, like a diamond. And so, when UV light, the heat, comes into the pavement it’s actually redirected. And that way it doesn’t all go in one direction down into the pavement. It actually helps the pavement act more like the natural surroundings. So it’s going to bring it to a lower emissive, or less radiant, as temperatures start to cool in the evening. The pavement won’t have gotten as hot and basically soaked in as deep as it would typically into the hard infrastructure.”
The way the Plus TI works is by increasing the Solar Reflective Index (SRI). The SRI is a scale from 0 to 100. Something completely black has a rating of 0 because it absorbs 100% of incoming solar radiation and thus increasing the surface temperature.
Something completely white, on the other hand, will have an SRI of 100 because it reflects 100% of incoming solar radiation, and thus keeps temperatures relatively cooler.
Holton says a typical asphalt pavement untreated with their Plus TI solution will have an SRI of around 10. A perfectly white road is ideal to help combat the urban heat island effect. But that it’s nearly impossible to keep a road white with dirt and debris keeping it constantly dirty. Even gray concrete roads come in with an SRI around 15 to 20.
The goal SRI index for Plus TI has been 29, which is the standard set by the US Green Building Council LEED Standards as well as the Institute for Sustainable Infrastructure (ISI) Standards.
A road treated with Plus TI has been able to increase the SRI anywhere between 30 and 40, which not only exceeds the standard by the US Green Building Council and the ISI, but it also has an overall cooling effect on the areas on and near the road.
Holton and Pavement Technology, Inc. hopes to continue piloting their product in cities across the country with the hopes cooling temperatures off in cities, reduce pollution, and lower your energy bills.