TY - JOUR
T1 - Local production, downward and regional transport aggravated surface ozone pollution during the historical orange-alert large-scale ozone episode in eastern China
AU - Zhang, Yibo
AU - Yu, Shaocai
AU - Chen, Xue
AU - Li, Zhen
AU - Li, Mengying
AU - Song, Zhe
AU - Liu, Weiping
AU - Li, Pengfei
AU - Zhang, Xiaoye
AU - Lichtfouse, Eric
AU - Rosenfeld, Daniel
N1 - Publisher Copyright:
© 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
PY - 2022/6
Y1 - 2022/6
N2 - Increasing severe and persistent ozone pollution in China has resulted in serious harm to human health in recent years, yet the precise pollution sources are poorly known because there is few knowledge on large-scale extreme ozone episodes. Here, we studied the formation of the historical orange-alert regional ozone episode in eastern China on 6 June, 2021, by combining process analysis, integrated source apportionment modelling, and chemical and meteorological data. Results show that during the pollution episode, 94% of cities in eastern China suffered ozone pollution, and 39% had daily maximum 8-h average ozone concentrations higher than 100 ppb. This is explained by favorable local ozone formation and transports provided by the prevailing northwestern winds in the upper air, and by sinking atmospheric motions favoring the persistence of high surface ozone concentrations. During daytime, local photochemical production induced an ozone increase of 0.3–28.4 ppb h−1 and vertical transport induced an ozone increase of 0.4–56.1 ppb h−1. As a consequence, vertical downward transport of ozone generated in the upper air by photochemical reactions aggravated surface ozone pollution. Surface ozone concentrations include 25.8–53.9% of ozone from local provincial emissions, 0–42.6% of ozone from inter-regional transports from neighboring regions, 4.6–23.1% of ozone from outer-regional transport, and 13.6–52.9% of ozone from boundary conditions in the selected cities. Overall, our findings show that favorable meteorological conditions promoted the chemical productions of ozone on the surface and at high altitudes, thus resulting in this heavy ozone pollution. In addition, regional and vertical downward transports of aloft ozone further aggravated the surface ozone pollution, leading to the large-scale extreme ozone pollution episode.
AB - Increasing severe and persistent ozone pollution in China has resulted in serious harm to human health in recent years, yet the precise pollution sources are poorly known because there is few knowledge on large-scale extreme ozone episodes. Here, we studied the formation of the historical orange-alert regional ozone episode in eastern China on 6 June, 2021, by combining process analysis, integrated source apportionment modelling, and chemical and meteorological data. Results show that during the pollution episode, 94% of cities in eastern China suffered ozone pollution, and 39% had daily maximum 8-h average ozone concentrations higher than 100 ppb. This is explained by favorable local ozone formation and transports provided by the prevailing northwestern winds in the upper air, and by sinking atmospheric motions favoring the persistence of high surface ozone concentrations. During daytime, local photochemical production induced an ozone increase of 0.3–28.4 ppb h−1 and vertical transport induced an ozone increase of 0.4–56.1 ppb h−1. As a consequence, vertical downward transport of ozone generated in the upper air by photochemical reactions aggravated surface ozone pollution. Surface ozone concentrations include 25.8–53.9% of ozone from local provincial emissions, 0–42.6% of ozone from inter-regional transports from neighboring regions, 4.6–23.1% of ozone from outer-regional transport, and 13.6–52.9% of ozone from boundary conditions in the selected cities. Overall, our findings show that favorable meteorological conditions promoted the chemical productions of ozone on the surface and at high altitudes, thus resulting in this heavy ozone pollution. In addition, regional and vertical downward transports of aloft ozone further aggravated the surface ozone pollution, leading to the large-scale extreme ozone pollution episode.
KW - Meteorological conditions
KW - Ozone pollution
KW - Photochemical production
KW - Process analysis
KW - Source contributions
KW - Vertical transport
UR - http://www.scopus.com/inward/record.url?scp=85127599100&partnerID=8YFLogxK
U2 - 10.1007/s10311-022-01421-0
DO - 10.1007/s10311-022-01421-0
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
AN - SCOPUS:85127599100
SN - 1610-3653
VL - 20
SP - 1577
EP - 1588
JO - Environmental Chemistry Letters
JF - Environmental Chemistry Letters
IS - 3
ER -