• 关键词：臭氧生成机制  时空变化特征  臭氧防治策略  上海市

• 基金项目：上海市科委科研计划重点项目（No.16DZ204605）

• 罗恢泓
• 华南理工大学环境与能源学院, 广州 510006

• 袁自冰
• 华南理工大学环境与能源学院, 广州 510006

• 郑君瑜
• 暨南大学环境与气候研究院, 广州 510632

• 段玉森
• 上海市环境监测中心, 上海 200235

• 杨雷峰
• 华南理工大学环境与能源学院, 广州 510006

• 黄志炯
• 暨南大学环境与气候研究院, 广州 510632

• 黄晓波
• 深圳市环境科学研究院, 深圳 518022

• 林小华
• 华南理工大学环境与能源学院, 广州 510006

• 贾光林
• 华南理工大学环境与能源学院, 广州 510006

• 李文石
• 华南理工大学环境与能源学院, 广州 510006

• 摘要：上海的臭氧污染呈逐年加重的趋势，深入了解臭氧的生成机制及其时空变化特征是采取科学有效防控措施的前提条件.本研究应用长三角地区最新的臭氧前体物排放清单和本地化WRF/ Modified SMOKE /CMAQ数值模型系统，对2017年8月1—9日上海市一次持续性臭氧污染事件进行了模拟研究.同时，在重现臭氧浓度变化趋势的基础上，针对一系列前体物防控措施及其对臭氧峰值浓度的影响开展了敏感性实验，建立了上海夏季臭氧污染爆发时段各区域臭氧及其前体物的非线性响应关系.研究表明，此次臭氧污染事件中上海市臭氧污染机制具有显著的时空变化特征，时间方面，上海市整体臭氧生成机制由NO_x控制经过渡区转变为VOCs控制；空间方面，上海北部及西部多处于NO_x控制，南部为过渡区，中部及东部则以VOCs控制为主，且大尺度环流是导致其时空变化的主要原因.当上海受大陆低压控制盛行偏南风时，区域传输以VOCs为主，臭氧的防控应侧重于NO_x减排；当上海受副高边缘控制主要吹偏北风时，区域传输以NO_x为主，臭氧的防控应侧重于VOCs减排；当上海受弱高压脊控制背景风微弱，区域传输不显著时，臭氧防控的重点应以VOCs和NO_x协同控制为主.在目前的预报技术下，大尺度环流特征通常可以提前48~72 h进行准确预报，因此，可以根据大尺度环流预报结果及时调整本地防控策略，以达到在不同污染特征下臭氧削峰的最大化效果.

• Abstract：The ozone pollution in Shanghai is becoming serious in recent years. In-depth understanding of ozone formation mechanism and its spatio-temporal variation is the pre-requisite of formulating effective control measures. This study applied the latest ozone precursor emission inventory in the Yangtze River Delta (YRD) and the localized WRF/Modified SMOKE/CMAQ numerical modeling system to simulate a continuous ozone pollution event in Shanghai during 1—9 August 2017. By replicating the temporal variation of ozone concentration, a series of sensitivity study with different precursor reduction degrees was conducted to establish the non-linear relationship between ozone and its precursors during pollution episodes. It was found that the ozone formation mechanism in Shanghai displayed significant spatio-temporal variations. Temporally, the overall ozone formation mechanism in Shanghai transformed from NO_x-limited to transitional regime then to VOCs-limited. Spatially, the northern and western area was under NO_x-limited, southern area was in transitional regime, while central and eastern area was more dominated by VOCs-limited. The large-scale circulation pattern played an important role in this spatio-temporal variation. When Shanghai was controlled by a continental low with prevailing southerly wind, VOCs was enriched in the transport air mass and local control should target on NO_x emission reduction; when Shanghai was controlled by western Pacific subtropical high with prevailing northerly wind, NO_x was enriched in the transport air mass and local control should target on VOCs emission reduction; when Shanghai was controlled by weak high-pressure ridge with weak background wind and regional transport, local control should target on VOCs/NO_x synergistic reduction. With the current forecast capability, the large-scale circulation pattern can be forecasted with good accuracy by 48~72 hours. Therefore, local control focus should be dynamically adjusted according to the large-scale circulation forecast, so as to maximize the ozone despiking efficiency under different pollution conditions.

• Key words：ozone formation mechanism  spatio-temporal pattern  ozone control strategies  Shanghai

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