Dramatic changes in atmospheric pollution source contributions for a coastal megacity in North China from 2011 to 2020

作者：Baoshuang Liu, Yanyang Wang, He Meng, Qili Dai, Liuli Diao, Jianhui Wu, Laiyuan Shi, Jing Wang, Yufen Zhang, Yinchang Feng · 年份：2022 · DOI：10.5194/acp-2021-957 · 被引用次数：2 · 研究领域：Air Quality and Health Impacts、Atmospheric chemistry and aerosols、Vehicle emissions and performance

Abstract. Understanding the effectiveness of long-term air pollution regulatory measures is important for control policy formulation. Efforts have been made using chemical transport modelling and statistical approaches to evaluate the efficacy of the Clean Air Action Plan (2013–2017, CAAP) and the Blue Sky Protection Campaign (2018–2020, BSPC) enacted in China. Changes in air quality due to reduction in emissions can be masked by meteorology, making it highly challenging to reveal the real effects of control measures. Knowledge gap still existed with respect to how sources changed before and after the CAAP and BSPC implemented, respectively, particularly in coastal area where anthropogenic emissions mixed with additional natural sources (e.g., marine aerosol). This work applied a machine learning-based meteorological normalization approach to decouple the meteorological effects from air quality trend in a coastal city in northern China (Qingdao). Secondly, the relative changes in source contributions to ambient PM2.5 with a ~10-year observation interval (2011–2012, 2016, and 2019) were also investigated. We discovered that the largest emission reduction section was likely from coal combustions, as the meteorologically normalized SO2 dropped by ~15.5 % per year and dispersion normalized SO42− decreased by ~41.5 % for annual average. Change in the meteorologically normalized NO2 was relatively stable (~1.0 % yr−1), and NO3− changed inappreciable in 2016–2019 but significantly h...