Assessment of the effectiveness of cool pavements on outdoor thermal environment in urban areas

Abstract

The impacts of cool pavement as a reflected coat on enhancing the thermal environment and reducing the consequences of near-surface heat islands were studied using a combination of computational tools and field measurements. Numerous studies explored how local microclimates are impacted by the built environment (Gong et al., July 2023) [1]. However, challenges were noted to estimate how pedestrians can be impacted (Givoni et al., January 2003) [2]. To describe outdoor microclimates, it is necessary to consider air temperature, mean radiant temperature (MRT), air velocity, and relative humidity (Stathopoulos et al., March 2004) [3]. Using Ladybug Tools extensions for Grasshopper, outdoor thermal environment was simulated during the summer in Maryvale community of Phoenix, Arizona. Field measurements were taken in the same community to compare effectiveness of cool pavements as compared to standard pavement surfaces. The field observations were used to verify and validate the models. According to our research, adopting high-reflectivity pavement will lower the pavement's surface temperature, which may assist in enhancing the quality of the air by preventing the creation of ground-level ozone. However, increasing pavement reflectivity (at albedo 0.35) would have an impact on people's thermal comfort at high temperatures, since it can potentially raise the MRT as more reflected radiation would hit people's bodies. While the mean radiant temperature was greater by 5–7 °C during the middle of the day, the surface temperature of cool pavement was 10–13 °C lower than that of standard pavement in the afternoon. After sunset, in every area, there was a slight reduction in the air temperature where reflective surfaces were used.