Meteorological and Air Quality Impacts of Heat Island Mitigation Measures in Three U.S. Cities

摘要

This report investigates the air pollution reduction benefits associated with mitigating urban heat islands in three U.S. cities. The effects of these measures in Salt Lake City, Baton Rouge, and Sacramento were evaluated through mesoscale meteorological and air quality modeling. The simulations indicate that for these three U.S. cities, adopting heat island reduction measures can result in various meteorological and air quality changes. The meteorological simulations suggest that each of the three pilot cities benefits from reduced ambient air temperatures. Decreases typically range from 1 to 2K (1.8 - 3.6oF) over modified areas. In Salt Lake City, reductions in ambient air temperatures reach up to 2K (3.6oF) at 1600 LST. The city achieves reductions in ozone concentrations of up to 3 or 4 ppb, the equivalent of about 3.5% if it were compared to an urban peak of 95 ppb. In Baton Rouge, reductions in ambient air temperatures of 0.75K (1.4oF) are possible and ozone reductions reach up to 4 or 5 ppb, the equivalent of about 4% if compared to an urban peak of 113 ppb. Finally, Sacramento enjoys reductions of 1.2K (2.2oF) as a result of heat island mitigation measures. Although these temperature reductions are not as large as those experienced in Salt Lake City, for example, their impacts on ozone are relatively larger, with reductions of up to 10 ppb from peak ozone concentrations (about 7% of the peak of 139 ppb).