Solar reflective pavements—A policy panacea to heat mitigation?
Cities worldwide are piloting the use of solar reflective coatings on roads to mitigate the Urban Heat Island (UHI). Solar reflective pavement has been praised as simple, low-cost solution with a demonstrated ability to reduce surface temperature. Less well understood is the effect of solar reflecti...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2020-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/ab87d4 |
| _version_ | 1797747529181298688 |
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| author | Ariane Middel V Kelly Turner Florian A Schneider Yujia Zhang Matthew Stiller |
| author_facet | Ariane Middel V Kelly Turner Florian A Schneider Yujia Zhang Matthew Stiller |
| author_sort | Ariane Middel |
| collection | DOAJ |
| description | Cities worldwide are piloting the use of solar reflective coatings on roads to mitigate the Urban Heat Island (UHI). Solar reflective pavement has been praised as simple, low-cost solution with a demonstrated ability to reduce surface temperature. Less well understood is the effect of solar reflective coatings on radiant heat, which influences human thermal exposure and comfort. We present the first biometeorological observations of solar reflective coating to investigate its thermal performance from a pedestrian perspective. Hourly transects were conducted in two Los Angeles neighborhoods with MaRTy , a mobile platform that measures air, surface, and mean radiant temperature. Transects were performed on July 30, 2019, a typical summer day with low wind speeds and maximum air temperature of 31 °C. The surface temperature of coated asphalt concrete was 4 °C to 6 °C lower than that of regular asphalt concrete, but coated surfaces reflected 118 Wm ^−2 more shortwave radiation on average and up to 168 Wm ^−2 more at noon. In the evening, MaRTy observed 20 to 30 Wm ^−2 of added reflected shortwave radiation on sidewalks next to the reflective pavement. Mean radiant temperature over reflective pavement was 4 °C higher during midday. Although air temperature was reduced by 0.5 °C in the afternoon, after-sunset cooling was negligible. Findings illustrate the benefits and disadvantages of reflective pavement with respect to various thermal performance metrics. Cities should weigh the tradeoffs of UHI mitigation, thermal exposure, implementation and maintenance costs, lifecycle, and other competing priorities in the context of space use. |
| first_indexed | 2024-03-12T15:51:52Z |
| format | Article |
| id | doaj.art-7085684cdc68497c8c6d6e32c1d2f26f |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T15:51:52Z |
| publishDate | 2020-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-7085684cdc68497c8c6d6e32c1d2f26f2023-08-09T15:07:05ZengIOP PublishingEnvironmental Research Letters1748-93262020-01-0115606401610.1088/1748-9326/ab87d4Solar reflective pavements—A policy panacea to heat mitigation?Ariane Middel0https://orcid.org/0000-0002-1565-095XV Kelly Turner1Florian A Schneider2Yujia Zhang3Matthew Stiller4School of Arts, Media and Engineering, Arizona State University , United States of America; School of Computing, Informatics, and Decision Systems Engineering, Arizona State University , United States of AmericaUrban Planning Department, Luskin School of Public Affairs, University of California Los Angeles , United States of AmericaSchool of Sustainability, Arizona State University , United States of AmericaSchool of Geographical Sciences and Urban Planning, Arizona State University , United States of AmericaDepartment of Geography, Kent State University , United States of AmericaCities worldwide are piloting the use of solar reflective coatings on roads to mitigate the Urban Heat Island (UHI). Solar reflective pavement has been praised as simple, low-cost solution with a demonstrated ability to reduce surface temperature. Less well understood is the effect of solar reflective coatings on radiant heat, which influences human thermal exposure and comfort. We present the first biometeorological observations of solar reflective coating to investigate its thermal performance from a pedestrian perspective. Hourly transects were conducted in two Los Angeles neighborhoods with MaRTy , a mobile platform that measures air, surface, and mean radiant temperature. Transects were performed on July 30, 2019, a typical summer day with low wind speeds and maximum air temperature of 31 °C. The surface temperature of coated asphalt concrete was 4 °C to 6 °C lower than that of regular asphalt concrete, but coated surfaces reflected 118 Wm ^−2 more shortwave radiation on average and up to 168 Wm ^−2 more at noon. In the evening, MaRTy observed 20 to 30 Wm ^−2 of added reflected shortwave radiation on sidewalks next to the reflective pavement. Mean radiant temperature over reflective pavement was 4 °C higher during midday. Although air temperature was reduced by 0.5 °C in the afternoon, after-sunset cooling was negligible. Findings illustrate the benefits and disadvantages of reflective pavement with respect to various thermal performance metrics. Cities should weigh the tradeoffs of UHI mitigation, thermal exposure, implementation and maintenance costs, lifecycle, and other competing priorities in the context of space use.https://doi.org/10.1088/1748-9326/ab87d4cool pavementurban heat islandheat mitigationpedestrian thermal exposure |
| spellingShingle | Ariane Middel V Kelly Turner Florian A Schneider Yujia Zhang Matthew Stiller Solar reflective pavements—A policy panacea to heat mitigation? Environmental Research Letters cool pavement urban heat island heat mitigation pedestrian thermal exposure |
| title | Solar reflective pavements—A policy panacea to heat mitigation? |
| title_full | Solar reflective pavements—A policy panacea to heat mitigation? |
| title_fullStr | Solar reflective pavements—A policy panacea to heat mitigation? |
| title_full_unstemmed | Solar reflective pavements—A policy panacea to heat mitigation? |
| title_short | Solar reflective pavements—A policy panacea to heat mitigation? |
| title_sort | solar reflective pavements a policy panacea to heat mitigation |
| topic | cool pavement urban heat island heat mitigation pedestrian thermal exposure |
| url | https://doi.org/10.1088/1748-9326/ab87d4 |
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