Department of Civil and Environmental Engineering, University of California, Davis, Davis, CA 95616, USA.
J Air Waste Manag Assoc. 2012 May;62(5):566-75. doi: 10.1080/10962247.2012.663325.
The effectiveness of emissions control programs designed to reduce concentrations of airborne particulate matter with an aerodynamic diameter < 2.5 microm (PM2.5) in California's San Joaquin Valley was studied in the year 2030 under three growth scenarios: low, medium, and high population density. Base-case inventories for each choice of population density were created using a coupled emissions modeling system that simultaneously considered interactions between land use and transportation, area source, and point source emissions. The ambient PM2.5 response to each combination of population density and emissions control was evaluated using a regional chemical transport model over a 3-week winter stagnation episode. Comparisons between scenarios were based on regional average and population-weighted PM2.5 concentrations. In the absence of any emissions control program, population-weighted concentrations of PM2.5 in the future San Joaquin Valley are lowest undergrowth scenarios that emphasize low population density. A complete ban on wood burning and a 90% reduction in emissions from food cooking operations and diesel engines must occur before medium- to high-density growth scenarios result in lower population-weighted concentrations of PM2.5. These trends partly reflect the fact that existing downtown urban cores that naturally act as anchor points for new high-density growth in the San Joaquin Valley are located close to major transportation corridors for goods movement. Adding growth buffers around transportation corridors had little impact in the current analysis, since the 8-km resolution of the chemical transport model already provided an artificial buffer around major emissions sources. Assuming that future emissions controls will greatly reduce or eliminate emissions from residential wood burning, food cooking, and diesel engines, the 2030 growth scenario using "as-planned" (medium) population density achieves the lowest population-weighted average PM2.5 concentration in the future San Joaquin Valley during a severe winter stagnation event.
The San Joaquin Valley is one of the most heavily polluted air basins in the United States that are projected to experience strong population growth in the coming decades. The best plan to improve air quality in the region combines medium- or high-density population growth with rigorous emissions controls. In the absences of controls, high-density growth leads to increased population exposure to PM2.5 compared with low-density growth scenarios (urban sprawl).
本研究旨在探讨 2030 年加利福尼亚圣华金河谷（San Joaquin Valley）在三种增长情景下（低密度、中密度和高密度）实施旨在降低空气动力学直径<2.5μm 的颗粒物（PM2.5）浓度的减排计划的有效性。每种人口密度选择的基础清单均使用耦合排放模型系统创建，该系统同时考虑土地利用和交通、面源和点源排放之间的相互作用。使用区域化学输送模型在为期 3 周的冬季停滞事件期间，评估了每种人口密度和减排控制组合的环境 PM2.5 响应。基于区域平均和人口加权 PM2.5 浓度对情景进行比较。在没有任何减排计划的情况下，未来圣华金河谷在强调低密度人口的增长情景下，人口加权 PM2.5 浓度最低。必须全面禁止木柴燃烧，并且必须将食物烹饪作业和柴油发动机的排放量减少 90%，中等到高密度的增长情景才会导致人口加权 PM2.5 浓度降低。这些趋势在一定程度上反映了这样一个事实，即现有市中心城区自然成为圣华金河谷新高密度增长的锚固点，它们靠近货物运输的主要交通走廊。在当前分析中，在交通走廊周围增加增长缓冲区的影响很小，因为化学输送模型的 8 公里分辨率已经在主要排放源周围提供了人为缓冲区。假设未来的排放控制将大大减少或消除住宅木柴燃烧、食物烹饪和柴油发动机的排放，那么在严重的冬季停滞事件中，使用“按计划”（中密度）人口密度的 2030 年增长情景在未来圣华金河谷实现了最低的人口加权平均 PM2.5 浓度。
圣华金河谷是美国污染最严重的空气盆地之一，预计在未来几十年将经历强劲的人口增长。改善该地区空气质量的最佳计划是将中密度或高密度的人口增长与严格的排放控制相结合。在没有控制的情况下，与低密度增长情景（城市扩张）相比，高密度增长会导致人口暴露于 PM2.5 的增加。
