MITIGATION OF URBAN HEAT ISLANDS : METEOROLOGY, ENERGY, AND AIR QUALITY IMPACTS

This paper presents results from energy, meteorological andphotochemical (air quality) modeling for the Los Angeles Basin, one ofthe largest and smoggiest urban regions in the U.S. and the world. Oursimulations suggest that by mitigating urban heat islands, savings of 5to 10 percent peak utility load may be possible. In addition, heat islandmitigation can reduce smog formation by 10-20 percent. in summer, whichis as effective as controlling emissions from all mobile sources in theregion. For a typical late-August episode, our simulations suggest thatimplementing cool cities in the Los Angeles Basin would have a net effectof reducing ozone concentrations. Peak concentrations at 3 pm decrease byup to 7 percent (from 220 down to 205 ppb) while the total ozone mass inthe mixed layer decreases by up to 640 metric tons (a decrease of 4.7percent). Largest reductions in concentrations at 3 pm are on the orderof 50 ppb whereas the largest increases are on the order of 20 ppb. Withrespect to the National Ambient Air Quality Standard, domain widepopulation weighted exceedance exposure to ozone decreases by up to 20percent during peak afternoon hours and by up to 10 percent during thedaytime.