中国背景臭氧浓度变化对我国近地面臭氧长期趋势的影响

近年来，我国大气细颗粒物污染治理取得显著成效，但臭氧污染呈现加重态势。控制臭氧污染不仅需要考虑我国本地人为污染物排放的贡献，还需要考虑自然排放及国外地区人为排放的贡献，即背景臭氧浓度的贡献。气候和人为排放格局的变化导致全球特别是东南亚等地区对流层臭氧自1995年以来显著上升。本项目聚焦中国背景臭氧浓度变化趋势的量化和归因，揭示上述变化在如何影响我国臭氧浓度，及在多大程度上抵消了我国通过人为减排控制臭氧污染做出的努力。本项目将探讨大气化学模型量化我国背景臭氧浓度的不确定性，并应用最新的全球污染物历史排放清单进行近25年的全球大气化学模拟，引入历史飞机、卫星观测臭氧数据作为模型结果约束，量化中国背景臭氧浓度自1995年来发生了怎样的变化并如何影响我国地面臭氧趋势，并通过敏感性试验和标记臭氧模拟等数值模拟技术解析关键影响区域和过程。项目结果将为评估全球臭氧变化及我国臭氧治理策略提供重要科学认识。

Surface ozone pollution over China is deteriorating in recent years even though remarkable improvement has been achieved for regulating fine particulate matters. Mitigation of ozone pollution requires the consideration of not only the Chinese local anthropogenic ozone enhancement, but also ozone from the natural sources and foreign anthropogenic emissions, i.e. the background ozone contributions. Changes in climate and global anthropogenic emission patterns have led to significant increases in global tropospheric ozone since 1995, especially in regions such as the Southeast Asia. The project aims to quantify the changes in Chinese background ozone concentration and their attributions since 1995, to reveal how these changes influence ozone over China and to what extent they offset our efforts to control ozone pollution through domestic anthropogenic emission reduction. This project will quantify the uncertainties in background ozone concentrations estimated from different chemical models, apply the latest historical global anthropogenic emission inventory in the model to simulate global ozone changes for nearly 25 years, and introduce the satellite and recently available IAGOS aircraft ozone observations to evaluate the model ability to reproduce historical ozone changes. The project thus then quantifies the changes in background ozone concentration over China since 1995, evaluates their contributions to the surface ozone trends, and analyzes the key regions and processes affecting ozone in China through a comprehensive set of sensitivity simulations and Tagged-Ozone techniques. The outcome of this project will provide important scientific insights for understanding global ozone changes and ozone regulation strategies in China.