Impacts of the East Asian monsoon on lower tropospheric ozone over coastal South China

Zhou, Derong; Ding, Aijun; Mao, Huiting; Fu, Congbin; Wang, Tao; Чан, Лю; Ding, K. Y.; Zhang, Yang; Liu, Jane; An, Lu; Hao, Nan

doi:10.1088/1748-9326/8/4/044011

Cited by 63 publications

(44 citation statements)

References 30 publications

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“…The YRD region is located to the south of the most polluted East China, and under the control of the East Asian Monsoon (Zhou et al, 2013). Long-range and regional transport of the air pollutants have been found to be important factors influencing air quality in this region (Ding et al, 2013a;Lin et al, 2013;Shen et al, 2014;Ding et al, 2016a).…”

Section: Regional Transport and Its Implications For Air Pollution Comentioning

confidence: 99%

The Impacts of Emission Control and Regional Transport on PM2.5 Ions and Carbon Components in Nanjing during the 2014 Nanjing Youth Olympic Games

Zhou

Huang

et al. 2017

Aerosol Air Qual. Res.

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Highly time-resolved measurements of water soluble ions, organic and elemental carbon concentrations in the particle diameter size range D p < 2.5 µm (PM 2.5 ) were performed at a downwind urban site in Nanjing in the western part of the Yangtze River Delta (YRD) in eastern China during the 2014 Youth Olympic Games (YOG). In this study, we discuss the impacts of emission control in Nanjing and the surrounding areas during the YOG and regional/long-range transport on PM 2.5 pollution in Nanjing. The average concentrations of NO 3 -, SO 4 2-, NH 4 + were 12.1 ± 9.9, 16.5 ± 9.2, 9.0 ± 5.4 µg m -3 during the YOG, and increased 34.3%, 53.7%, 43.9% after the YOG, respectively. The control of construction or on-road soil dust and control of industry led to the decrease of Ca 2+ concentration by 55% and SO 2 concentration by 46%. However, SO 4 2-concentrations remained at relatively high levels, suggesting a significant impact of regional pollution to secondary fine particles in Nanjing. Strong correlations between OC and EC were observed during and after the YOG. A higher percentage (41%) of secondary organic carbon in Nanjing during the YOG periods was consistent with high potential photochemistry and low contributions from coal combustion. Lagrangian dispersion modelling results proved that the city clusters along the Nanjing and Shanghai axis were the major source region for high PM 2.5 pollution in upwind Nanjing. This work shows that short-term strict control measures could improve the air quality, especially that affected by the primary pollutants; however, regional collaborative control strategy across administrative borders in the YRD is needed for a substantial improvement of air quality.

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Section: Regional Transport and Its Implications For Air Pollution Comentioning

confidence: 99%

The Impacts of Emission Control and Regional Transport on PM2.5 Ions and Carbon Components in Nanjing during the 2014 Nanjing Youth Olympic Games

Zhou

Huang

et al. 2017

Aerosol Air Qual. Res.

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“…No previous studies, to our knowledge, have systematically examined the impacts of the EASM on interannual variations of summertime O 3 in China. Recently, Zhou et al (2013Zhou et al ( ) analyzed 2000Zhou et al ( -2010 ozonesonde data from Hong Kong and found a close link between lower tropospheric O 3 and the East Asian monsoon on interannual scales, but their analyses were focused on O 3 in Hong Kong in spring and autumn. We present here a study to examine the impacts of the EASM on interannual variations of summertime surface-layer O 3 concentrations over China, based on 1986-2006 simulations of O 3 concentrations using the global chemical transport model GEOS (Goddard Earth Observing System)-Chem driven by the assimilated meteorological fields.…”

Section: H Liao Et Al: Interannual Variations Of Summertime Surfacementioning

confidence: 99%

Impacts of the East Asian summer monsoon on interannual variations of summertime surface-layer ozone concentrations over China

2014

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Abstract. We apply a global three-dimensional Goddard Earth Observing System (GEOS) chemical transport model (GEOS-Chem) driven by the NASA/GEOS-4 assimilated meteorological fields to quantify the impacts of the East Asian summer monsoon (EASM) on interannual variations of June-July-August (JJA) surface-layer O 3 concentrations over China. With anthropogenic emissions fixed at year 2005 levels, the model simulation for years shows that the changes in meteorological parameters alone lead to interannual variations in JJA surface-layer O 3 concentrations by 2-5 % over central eastern China, 1-3 % in northwestern China, and 5-10 % over the Tibetan Plateau as well as the border and coastal areas of southern China, as the interannual variations are relative to the average O 3 concentrations over the 21 yr period. Over the years 1986-2006, the O 3 concentration averaged over all of China is found to correlate positively with the EASM index with a large correlation coefficient of +0.75, indicating that JJA O 3 concentrations are lower (or higher) in weaker (or stronger) EASM years. Relative to JJA surface-layer O 3 concentrations in the strongest EASM years (1990, 1994, 1997, 2002, and 2006), O 3 levels in the weakest EASM years (1988, 1989, 1996, 1998, and 2003) are lower over almost all of China with a national mean lower O 3 concentration by 2.0 ppbv (parts per billion by volume; or 4 %). Regionally, the largest percentage differences in O 3 concentration between the weakest and strongest EASM years are found to exceed 6 % in northeastern China, southwestern China, and over the Tibetan Plateau. Sensitivity studies show that the difference in transboundary transport of O 3 is the most dominant factor that leads to lower-O 3 concentrations in the weakest EASM years than in the strongest EASM years, which, together with the enhanced vertical convections in the weakest EASM years, explain about 80 % of the differences in surface-layer O 3 concentrations between the weakest and strongest EASM years. We also find that the impacts the EASM strength on JJA surface-layer O 3 can be particularly strong (comparable in magnitude to the impacts on O 3 by changes in anthropogenic emissions over years for certain years. The largest increases in O 3 by anthropogenic emissions are simulated over southeastern China, whereas the largest impacts of the EASM on O 3 are found over central and western China.

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“…Hong Kong is a typical coastal city in the PRD region. Under the influence of the East Asian monsoon, this region is controlled by the southerly winds bringing marine inflow from the South China Sea in summer, while in winter it is downwind from the North China Plains and East China and is dominated by the continental outflow Lam et al, 2001;Zhou et al, 2013). Thus, it is an ideal place for exploring the characteristics of optical properties for continental and marine aerosols.…”

Section: Introductionmentioning

confidence: 99%

Observations of aerosol optical properties at a coastal site in Hong Kong, South China

et al. 2017

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Abstract. Temporal variations in aerosol optical properties were investigated at a coastal station in Hong Kong based on the field observation from February 2012 to February 2015. At 550 nm, the average light-scattering (151 ± 100 Mm −1 ) and absorption coefficients (8.3 ± 6.1 Mm −1 ) were lower than most of other rural sites in eastern China, while the single-scattering albedo (SSA = 0.93 ± 0.05) was relatively higher compared with other rural sites in the Pearl River Delta (PRD) region. Correlation analysis confirmed that the darkest aerosols were smaller in particle size and showed strong scattering wavelength dependencies, indicating possible sources from fresh emissions close to the measurement site. Particles with D p of 200-800 nm were less in number, yet contributed the most to the light-scattering coefficients among submicron particles. In summer, both BC / CO and SO 2 / BC peaked, indicating the impact of nearby combustion sources on this site. Multi-year backward Lagrangian particle dispersion modeling (LPDM) and potential source contribution (PSC) analysis revealed that these particles were mainly from the air masses that moved southward over Shenzhen and urban Hong Kong and the polluted marine air containing ship exhausts. These fresh emission sources led to low SSA during summer months. For winter and autumn months, contrarily, BC / CO and SO 2 / BC were relatively low, showing that the site was more under influence of well-mixed air masses from long-range transport including from South China, East China coastal regions, and aged aerosol transported over the Pacific Ocean and Taiwan, causing stronger abilities of light extinction and larger variability of aerosol optical properties. Our results showed that ship emissions in the vicinity of Hong Kong could have visible impact on the light-scattering and absorption abilities as well as SSA at Hok Tsui.

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Impacts of the East Asian monsoon on lower tropospheric ozone over coastal South China

Cited by 63 publications

References 30 publications

The Impacts of Emission Control and Regional Transport on PM2.5 Ions and Carbon Components in Nanjing during the 2014 Nanjing Youth Olympic Games

The Impacts of Emission Control and Regional Transport on PM2.5 Ions and Carbon Components in Nanjing during the 2014 Nanjing Youth Olympic Games

Impacts of the East Asian summer monsoon on interannual variations of summertime surface-layer ozone concentrations over China

Observations of aerosol optical properties at a coastal site in Hong Kong, South China

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