MITIGATION OF URBAN HEAT ISLANDS - MATERIALS, UTILITY PROGRAMS, UPDATES

Elevated temperatures in urban 'heat islands' increase cooling energy use and accelerate the formation of urban smog. Urban shade trees and light-colored surfaces can offset or reverse the heat island and conse rve energy. Implementation of heat island mitigation measures is now a prominent part of President Clinton's Climate Change Action Plan to c ontrol the emissions of greenhouse gases, necessitating a better under standing of the quantitative benefits of these control measures. We pr esent recent measurements of the air-conditioning savings for houses i n Sacramento and Florida, and air temperature measurements at White Sa nds National Monument, New Mexico. We also discuss the results of mete orological and smog simulations for the Los Angeles Basin. The albedo of a city may be increased gradually if high-albedo surfaces are chose n to replace darker materials during routine maintenance of roofs and roads. Such high-albedo surfaces may last longer than their convention al dark counterparts. Utility-sponsored incentive programs, product la beling, and standards could promote the use of high-albedo materials f or buildings and roads, and several paint manufacturers have expressed interest in participating in a 'cool surfaces' labeling program. We e xamine the spectral reflectance of various white coatings and building materials that might be labeled in such a program.