AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Air Quality Impacts of Widespread Adoption of Cool Roofing Technology in the South Coast Air Basin: Ozone and PM2.5
SCOTT A. EPSTEIN, Sang-Mi Lee, Aaron Katzenstein, Salvatore Farina, Pouya Vahmani, George Ban-Weiss, Philip Fine, South Coast Air Quality Management District
Abstract Number: 220 Working Group: Urban Aerosols
Abstract Cool roofs are designed to reflect a larger fraction of incident sunlight than traditional roofs, reducing the urban heat island effect and leading to a reduction in emissions from decreased air conditioning use. Lower daytime ambient temperatures and reduced NOx emissions from energy production should slow the formation of ozone and PM2.5. However, widespread adoption of cool roofs in a large urban area like the South Coast Air Basin of California may change important meteorological parameters that govern pollutant concentrations such as the planetary boundary layer height and the ventilation rate. In additional, several cool roofing materials reflect UV radiation more effectively than traditional roofing materials, increasing the path length for ozone formation, potentially leading to an increase in ozone concentrations.
We developed a comprehensive database of rooftop area apportioned by sector to project changes in albedo in response to potential air pollution control strategies within the South Coast Air Basin, a region encompassing the greater Los Angeles area with 17 million residents and significant air pollution problems. MODIS-derived high-resolution albedo measurements under a current and a future policy scenario were used along with the Weather Research and Forecasting (WRF) model to simulate Southern California meteorological fields for each day of 2012 under each scenario. The Community Multi-scale Air Quality Management System (CMAQ) was then employed to forecast changes in ozone and PM2.5 concentrations under future emissions scenarios and meteorology. The multi-wavelength albedo parametrization used to calculate photochemical rate constants within CMAQ was modified to capture the effects of increased UV reflection from widespread cool roof implementation. Results of these simulations can help guide existing cool roof policies at the state and national level. Findings will inform the development of an Ozone and PM2.5 control measure focused on the strategic implementation of cool roof technologies and improvement of existing local cool roof ordinances in the South Coast Air Basin.