降低长三角地区O3暴露风险的前体物减排路径优化研究

O₃污染的防治需要在分析O₃人群暴露风险特征的基础上，对前体物的减排路径进行优化.长三角地区是我国O₃浓度高、暴露风险大、前体物排放集中的地区之一，其减排路径的优化分析对于全国而言具有借鉴意义.本文以GB 3095—2012《环境空气质量标准》中O₃浓度二级标准限值(160μg/m³)为目标，基于长三角地区的人群暴露风险探讨了不同减排路径下的O₃污染控制效果.首先，运用WRF-CAMx模型，依据不同的NO_x和VOCs减排率模拟了121种减排情景作为基础数据集，引入响应曲面模型(RSM)来划分长三角地区不同城市的控制区类型，并结合人口暴露风险指数来评价O₃暴露的风险程度，将中高暴露风险地区与控制区耦合，设置HN区(NO_x控制区中的O₃暴露中高风险城市)和HV区(VOCs控制区中的O₃暴露中高风险城市)；其次，设置了7条不同的NO_x

Optimization of Precursors Mitigation Paths to Reduce the Risk from O3 Exposure in the Yangtze River Delta

Controlling ozone (O₃) pollution requires optimizing precursor emission reduction pathways based on an analysis of the characteristics of public exposure to ambient O₃. The Yangtze River Delta is one of the regions with high O₃ concentration, large exposure, and concentrated precursor emissions in China. Analyzing its emission reduction pathway optimization has reference significance for the whole country. Targeting O₃ concentration of 160 μg/m3 in the national air quality standard, this study explored the effect of O₃ pollution control under different reduction paths based on the population exposure risk in the Yangtze River Delta Region. The WRF-CAMx model was used to simulate the ozone concentration under 121 scenarios of different NO_x and VOCs reduction ratios, and the response surface model (RSM) was introduced to distinguish the sensitivity of O₃ to NO_x and VOCs in different cities of the Yangtze River Delta, and the population exposure risk index was combined to evaluate the risk level of O₃ exposure, coupling the medium and high exposure risk areas with the control area (HN: O₃ exposure in NO_x control areas in high and medium risk cities; HV: O₃ exposure in VOCs control areas in high and medium risk cities). Based on the modeling results, seven NO_x/VOCs mitigation pathways were designed in this study, and the ozone control efficiency of different pathways was analyzed to formulate the best emission reduction strategies. The results show that: (1) The cities in the central part of the Yangtze River Delta are main VOCs-sensitive zones, and the cities in the south and north are main NO_x-sensitive areas; the cities with high O₃ exposure risk account for about 41% of the total number of cities, mainly concentrated in the central and northern regions of the Yangtze River Delta. (2) The paths with the highest control efficiency are NO_x-only emission reduction and VOCs-only emission reduction in the HN and HV zones, respectively. Some grids change from VOCs-sensitive to NO_x-sensitive as NO_x emission reduces in the whole region from the perspective of overall ozone control efficiency. (3) The optimal ratio of NO_x /VOCs in HV region and HN region is 1/3-1/2 and 1-2 , respectively. Short-term O₃ control in the Yangtze River Delta HV region should focus on VOCs control, long-term O₃ control should focus more on NO_x control, and O₃ control in the HN region needs to focus more on NO_x control.