PDRCs can be applied to building roofs and urban shelters to significantly lower surface temperatures with zero energy consumption by reflecting heat out of the urban environment and into outer space. The primary obstacle of PDRC implementation in urban areas is the glare that may be caused through the reflectance of visible light onto surrounding buildings. Colored PDRC surfaces may mitigate glare issues, such as Zhai et al. "Super-white paints with commercial high-index (n~1.9) retroreflective spheres," as per Mandal et al., or the use of retroreflective materials (RRM) may also mitigate glare, although further research and development is needed. Surrounding buildings without PDRC application may weaken the cooling power of PDRCs.