Dominant patterns of summer ozone pollution in eastern China and associated atmospheric circulations

Yin, Zhicong; Cao, Bufan; Wang, Huijun

doi:10.5194/acp-19-13933-2019

Cited by 57 publications

(27 citation statements)

References 31 publications

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“…Anthropogenic emissions are the key in driving change in surface O 3 . With rapid development of industrialization and urbanization, anthropogenic emissions of NO x and VOCs, two major precursors of O 3 formation, have been increasing significantly in China over the past several decades (Zeng et al, 2019). For instance, tropospheric columns of NO 2 (TCNO 2 ), an indicator of anthropogenic emission intensity of NO x were increased by 307 % in Beijing from 1996-2011 (Huang et al, 2013), which caused a strong increasing trend of O 3 in the lower troposphere.…”

Section: Introductionmentioning

confidence: 99%

“…However, little light was shed on change in surface O 3 compared to its counterpart PM 2.5 which was elevated to the severe pollution level in eastern China, especially over the North China Plain (NCP) region Zhai et al, 2019). The severity of PM 2.5 pollution has been largely alleviated after the stringent emission control strategies were implemented by the Chinese government at a national level in 2013 (Zeng et al, 2019). According to the estimate by Multi-resolution Emission Inventory in China (MEIC), anthropogenic emissions of PM 2.5 decreased by approximately 60 % and NO x emissions decreased by 21 %.…”

Section: Introductionmentioning

confidence: 99%

“…Such a complex terrain is not conducive to dispersion and dilution of air pollutants and makes them easily trapped. Meanwhile, the total energy consumption was increased by more than a factor of 5 from 1985-2016 (Zeng et al, 2019). The NCP has become one of the most polluted regions in China.…”

Section: Introductionmentioning

confidence: 99%

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Rapid increase in summer surface ozone over the North China Plain during 2013–2019: a side effect of particulate matter reduction control?

Huang

Zhao

et al. 2021

Atmos. Chem. Phys.

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Abstract. While the elevated ambient levels of particulate matters with aerodynamic diameter of 2.5 µm or less (PM2.5) are alleviated largely with the implementation of effective emission control measures, an opposite trend with a rapid increase has been seen in surface ozone (O3) in the North China Plain (NCP) region over the past several years. It is critical to determine the real culprit causing such a large increase in surface O3. In this study, 7-year surface observations and satellite retrieval data are analyzed to determine the long-term change in surface O3 as well as driving factors. Results indicate that anthropogenic emission control strategies and changes in aerosol concentrations as well as aerosol optical properties such as single-scattering albedo (SSA) are the most important factors driving such a large increase in surface O3. Numerical simulations with the National Center for Atmospheric Research (NCAR) Master Mechanism (MM) model suggest that reduction of O3 precursor emissions and aerosol radiative effect accounted for 45 % and 23 % of the total change in surface O3 in summertime during 2013–2019, respectively. Planetary boundary layer (PBL) height with an increase of 0.21 km and surface air temperature with an increase of 2.1 ∘C contributed 18 % and 12 % to the total change in surface O3, respectively. The combined effect of these factors was responsible for the rest of the change. Decrease in SSA or strengthened absorption property of aerosols may offset the impact of aerosol optical depth (AOD) reduction on surface O3 substantially. While the MM model enables quantification of an individual factor's percentage contributions, it requires further refinement with aerosol chemistry included in the future investigation. The study indicates an important role of aerosol radiative effect in development of more effective emission control strategies on reduction of ambient levels of O3 as well as alleviation of national air quality standard exceedance events.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Rapid increase in summer surface ozone over the North China Plain during 2013–2019: a side effect of particulate matter reduction control?

Huang

Zhao

et al. 2021

Atmos. Chem. Phys.

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“…We extract the information by comparing Neg with Pos to find the changes of each pattern. Yin et al (2019) explored dominant patterns of summer O3 pollution and associated atmospheric circulation changes in eastern China.…”

Section: Impacts Of Swp Change On O3 Concentration Variationmentioning

confidence: 99%

Dynamic Processes Dominating Ozone Variability in Warm Seasons of 2014–2018 over the Yangtze River Delta Region, China

Gao

Xie

Liu

et al. 2020

Preprint

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Abstract. Ozone (O3) pollution is of great concern in the Yangtze River Delta (YRD) region of China, and the regional O3 pollution is closely associated with dominant weather systems. With a focus on the warm seasons (April–September) from 2014 to 2018, we quantitatively analyze the characteristics of O3 variations over the YRD, the impacts of large-scale and synoptic-scale circulations on the variations and the associated meteorological controlling factors, based on observed ground-level O3 and meteorological data. Our analysis suggests an increasing trend of the regional mean O3 concentration in the YRD at 1.81 ppb per year over 2014–2018. Spatially, the empirical orthogonal function (EOF) analysis suggests the dominant mode accounting for 65.70 % variation in O3, implying that an increase in O3 is the dominant tendency in the entire YRD. Meteorology is estimated to increase the regional mean O3 concentration by 2.81 ppb at most from 2014 to 2018. Relative humidity is found to be the most influential meteorological factor impacting O3 concentration. As the atmospheric circulation can affect local meteorological factors and O3 levels, we identify five dominant synoptic weather patterns (SWPs) in the warm seasons in the YRD using the t-mode principal component analysis (PTT) classification. The typical weather systems of SWPs include western Pacific Subtropical High (WPSH) under SWP1, a continental high under SWP2, an extratropical cyclone under SWP3, a southern low pressure and WPSH under SWP4 and the north China anticyclone under SWP5. The annual variations of all five SWPs are favorable to the increase in O3 concentrations over 2014–2018. Moreover, the change in SWP intensity contributes more to the O3 inter-annual variation than the SWP frequency change. The SWP intensity change includes the weakening and northward-extending of the western Pacific subtropical high (WPSH) under SWP1, the weakening of the continental high under SWP2, an extratropical cyclone strengthening under SWP3, the southern low pressure weakening and WPSH weakening under SWP4, and the north China anticyclone weakening under SWP5. All these changes prevent the water vapor in the southern sea from being transported to the YRD, and increase air temperature in the YRD. In addition, the descending motions strengthen in the YRD located behind the trough and in front of the ridge due to the strengthening of the ridge and trough in the westerlies. Then, the strengthened descending motion leads to less cloud cover and strong solar radiation, which are favorable to O3 formation and accumulation. Finally, we reconstruct an EOF mode 1 time series that shows high correlation with the original O3 time series, and the reconstructed time series performs well in defining the change in SWP intensity according to the unique feature under each of the SWPs.

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“…As an air pollutant, surface ozone (O 3 ) is harmful to human health and vegetation growth, such as by damaging human lungs (Jerrett et al, 2009;Day et al, 2017) and destroying forest and agricultural crops (Yue et al, 2017). After the emission control following the "13th Comprehensive Work Plan for Energy Saving and Emission Reduction in China" since 2016, concentrations of many pollutants have decreased over the past few years in China but not of O 3 .…”

Section: Introductionmentioning

confidence: 99%

Ozone variability induced by synoptic weather patterns in warm seasons of 2014–2018 over the Yangtze River Delta region, China

et al. 2021

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Abstract. Ozone (O3) pollution is of great concern in the Yangtze River Delta (YRD) region of China, and the regional O3 pollution is closely associated with dominant weather systems. With a focus on the warm seasons (April–September) from 2014 to 2018, we quantitatively analyze the characteristics of O3 variations over the YRD, the impacts of large-scale and synoptic-scale circulations on the O3 variations and the associated meteorological controlling factors, based on observed ground-level O3 and meteorological data. Our analysis suggests an increasing trend of the regional mean O3 concentration in the YRD at 1.8 ppb per year over 2014–2018. Spatially, the empirical orthogonal function analysis suggests the dominant mode accounting for 65.7 % variation in O3, implying that an increase in O3 is the dominant tendency in the entire YRD region. Meteorology is estimated to increase the regional mean O3 concentration by 3.1 ppb at most from 2014 to 2018. In particular, relative humidity (RH) plays the most important role in modulating the inter-annual O3 variation, followed by solar radiation (SR) and low cloud cover (LCC). As atmospheric circulations can affect local meteorological factors and O3 levels, we identify five dominant synoptic weather patterns (SWPs) in the warm seasons in the YRD using the t-mode principal component analysis classification. The typical weather systems of SWPs include the western Pacific Subtropical High (WPSH) under SWP1, a continental high and the Aleutian low under SWP2, an extratropical cyclone under SWP3, a southern low pressure and WPSH under SWP4 and the north China anticyclone under SWP5. The variations of the five SWPs are all favorable to the increase in O3 concentrations over 2014–2018. However, crucial meteorological factors leading to increases in O3 concentrations are different under different SWPs. These factors are identified as significant decreases in RH and increases in SR under SWP1, 4 and 5, significant decreases in RH, increases in SR and air temperature (T2) under SWP2 and significant decreases in RH under SWP3. Under SWP1, 4 and 5, significant decreases in RH and increases in SR are predominantly caused by the WPSH weakening under SWP1, the southern low pressure weakening under SWP4 and the north China anticyclone weakening under SWP5. Under SWP2, significant decreases in RH, increases in SR and T2 are mainly produced by the Aleutian low extending southward and a continental high weakening. Under SWP3, significant decreases in RH are mainly induced by an extratropical cyclone strengthening. These changes in atmospheric circulations prevent the water vapor in the southern and northern sea from being transported to the YRD and result in RH significantly decreasing under each SWP. In addition, strengthened descending motions (behind the strengthening trough and in front of the strengthening ridge) lead to decreases in LCC and significant increases in SR under SWP1, 2, 4 and 5. The significant increases in T2 would be due to weakening cold flow introduced by a weakening continental high. Most importantly, the changes in the SWP intensity can make large variations in meteorological factors and contribute more to the O3 inter-annual variation than the changes in the SWP frequency. Finally, we reconstruct an empirical orthogonal function (EOF) mode 1 time series that is highly correlated with the original O3 time series, and the reconstructed time series performs well in defining the change in SWP intensity according to the unique feature under each of the SWPs.

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Dominant patterns of summer ozone pollution in eastern China and associated atmospheric circulations

Cited by 57 publications

References 31 publications

Rapid increase in summer surface ozone over the North China Plain during 2013–2019: a side effect of particulate matter reduction control?

Rapid increase in summer surface ozone over the North China Plain during 2013–2019: a side effect of particulate matter reduction control?

Dynamic Processes Dominating Ozone Variability in Warm Seasons of 2014–2018 over the Yangtze River Delta Region, China

Ozone variability induced by synoptic weather patterns in warm seasons of 2014–2018 over the Yangtze River Delta region, China

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