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Impact of Biomass Burning and Vertical Mixing of Residual‐Layer Aged Plumes on Ozone in the Yangtze River Delta, China: A Tethered‐Balloon Measurement and Modeling Study of a Multiday Ozone Episode
Author(s) -
Xu Zhengning,
Huang Xin,
Nie Wei,
Shen Yicheng,
Zheng Longfei,
Xie Yuning,
Wang Tianyi,
Ding Ke,
Liu Lixia,
Zhou Derong,
Qi Ximeng,
Ding Aijun
Publication year - 2018
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2018jd028994
Subject(s) - environmental science , delta , troposphere , atmospheric sciences , trace gas , ozone , planetary boundary layer , pollution , ceilometer , mixing ratio , climatology , meteorology , aerosol , geology , geography , ecology , turbulence , aerospace engineering , engineering , biology
Ozone (O 3 ) is one of the most important trace gases in the troposphere because of its impact on human health, crop yield, climate change, and atmospheric oxidizing capacity. In recent years, China has suffered from deleterious O 3 pollution in many regions, especially in eastern China during summer. However, understanding the causes of high O 3 pollution episodes is still limited because existing measurements were mainly conducted at the surface level. In this study, we conducted an intensive tethered‐balloon measurement at the Station for Observing Regional Processes of the Earth System in the Yangtze River Delta during a multiday O 3 episode in mid‐June 2014, with the highest hourly surface O 3 record (142 ppbv) at the station in 2014. By integrating available ground‐based, remote sensing and aircraft measurement data together with chemical transport modeling and Lagrangian dispersion modeling, we carried out a comprehensive analysis of the main source and formation mechanism for two typical days during the multiday O 3 episode. On 11 June, agricultural straw burning in the north significantly enhanced O 3 concentration (40–50 ppbv) above the planetary boundary layer (PBL) over Nanjing and further influenced the downwind surface O 3 in the following days. On 14 June, regional photochemically aged air masses from city clusters in the Yangtze River Delta substantially influenced early morning ground O 3 concentrations by vertical mixing from the residual layer and contributed to PBL daytime O 3 buildup. This study provides a clear picture of the transport and mixing of O 3 and relevant pollutants in the PBL from different sources and highlights the significance of regional emission control in the mitigation of photochemical pollution in eastern China.