Pacoima Cool Pavement Pilot — 700,000 sq ft of Reflective Coatings in Los Angeles, Measured Over 12 Months

In summer 2022 a partnership led by roofing manufacturer GAF (through its Community Matters initiative) with Climate Resolve, Pacoima Beautiful, Altostratus and the City of Los Angeles applied the solar-reflective coating DuraShield-SR to more than 700,000 square feet of neighbourhood streets in Pacoima, plus coatings on basketball courts, parking lots and a school playground. Planetizen describes it as the largest contiguous application of cool pavement coatings known to date.
The monitoring ran for 12 months with 73 mobile transects plus weather stations, satellite, aircraft and drone data. The peer-reviewed paper (Taha, Environmental Research Communications, 2024) reports maximum street-segment-averaged afternoon air-temperature differences of up to 1.9°C during a September 2022 heatwave; on hot non-heatwave days differences were up to 1.4°C (versus a reference) and surface-temperature reductions up to 9.2°C. Secondary coverage cites rounder Fahrenheit figures (up to 3.5°F air, about 1.5°F mean radiant temperature), and mean radiant temperature gains were modest.
Caveats: these are 'up to' peak values; benefits in typical summer weather were smaller and not always present; the result comes from one neighbourhood; the study's author leads Altostratus, which conducted it, and the coating maker sponsored the project. The authors describe reflective pavement as a complement to, not a replacement for, trees and shade. This is a heat-adaptation measure with no direct carbon, biodiversity or water benefits.

Read the full analysis: https://dev.planetizen.com/node/129208