Decade scale evolution of ozone air pollution in the lower Fraser Valley, B.C.

最近对不列颠哥伦比亚省下弗雷泽河谷（LFV）过去二十年臭氧空气污染的研究表明，臭氧浓度的时空变化趋势显著。这些趋势包括污染质心的东移和超标总数的全面减少，并且与臭氧前体排放的时间下降趋势是平行的。假设前体的趋势是由于大温哥华地区和弗雷泽谷地区的空气质量管理计划中包含的减排战略。我们将利用数值模拟研究，根据过去观测到的综合气象条件，研究污染趋势。将根据气象聚类分析得出的标准进行节目选择。该模型系统将使用过去二十年中连续几年的排放清单来运行。这项工作将以一个已被证明对过去发生和将来可能发生的排放变化（氮氧化物和挥发性有机化合物的总减少量、化学形态的变化以及排放的空间和时间变化）作出反应的模拟系统为基础。将通过证明它们能够成功地捕捉到LFV中与排放和气象变化相关的光化学污染的年代际演变来评估模式。通过所研究的序列，利用化学过程分析和臭氧羽流的时空分析来研究环境污染对排放变化的响应。总的研究目标是对环境臭氧与低海拔地区臭氧前体排放之间的关系提供与政策有关的理解。这项工作将在科学上可信，将基于适合任务的方法，并将以直接导致决策和监管领域的方式提出。

Recent studies of ozone air pollution in the Lower Fraser Valley (LFV) of British Columbia over the past two decades have demonstrated marked spatio-temporal trends of ozone concentration. These trends consist of an eastward shift in the centroid of pollution, and overall reduction in the total number of exceedances, and have been in parallel with downward temporal trends in emissions of ozone precursors. It is assumed that the trends in precursors have been as a result of emissions reduction strategies contained in air quality management plans by Metro Vancouver and Fraser Valley Regional District. The pollution trends will be studied using numerical modelling studies based on composite meteorological conditions during observed episodes in the past. Episode selection will be made using criteria drawing from a meteorological cluster analysis. The modelling system will be run using emissions inventories from a sequence of years over the past two decades. The work will be based on a modelling system that has been demonstrated to be responsive to emissions changes (gross reductions in NOx and VOC, changes in chemical speciation and spatial and temporal shifts in emissions) that have occurred in the past, and are likely to occur in future. Models will be evaluated by demonstrating that they can successfully capture the decadal evolution of photochemical pollution in the LFV in relation to changes in emissions and meteorology. The response of ambient pollution to emissions changes will be investigated using chemical process analysis and spatio-temporal analysis of ozone plumes through the sequence studied. The overall study objective is to provide a policy relevant understanding of the relationship between ambient ozone and emissions of ozone precursors in the LFV. The work will be scientifically credible, will be based on methods appropriate to the tasks, and will be presented in ways that lead directly into the policy-making and regulatory realms.