- 일시 : 2016.12.7. (수) 16:00~
- 주제 : Air quality management strategy in the Los Angeles air basin
- 내용 :
Los Angeles air basin experiences the worst air quality in the United States of America. It is required to meet federal air quality standards of 8-hour ozone, and annual and daily PM2.5 standard by 2031, 2025, and 2019, respectively. Substantial emissions reduction is needed to meet the standard. Numerical modeling approach was utilized to develop strategies to attain the standards. The Los Angeles air basin needs over 80 % reductions of NOx emission from 2012 level to meet the 8-hour ozone standard in 2031. This ozone strategy is expected to benefit PM2.5 and greenhouse gas reduction goals.
- 일시: 2016.12.9. (금) 15:30~
- 주제: Impacts of Cooling Roofing Technology in the Los Angeles.
- 내용 :
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 parameterization 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.