A study of aerosol optical properties during ozone pollution episodes in 2013 over Shanghai, China

Cs, Shi; Wang, Shanshan; Liu, Rui; Zhou, Rui; Li, Donghui; Wen-xin, Wang; Li, Zhengqiang; Cheng, Tiantao; Zhou, Bin

doi:10.1016/j.atmosres.2014.09.002

Cited by 56 publications

(24 citation statements)

References 52 publications

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“…Being the biggest city in China, Shanghai (with more than 22 million people) is situated on the east coast (longitude 120°51′-122°12′E~latitude 30°40′-31°53′N) (Fig. 1), and is considered one of the most prosperous and densely populated in the world (Feng et al, 2010;Shi et al, 2015). There are 12 subway lines and 266 subway stations in Shanghai at present.…”

Section: Introductionmentioning

confidence: 99%

Physico-chemical characterization of PM2.5 in the microenvironment of Shanghai subway

Lü

Liu

Zhang

et al. 2015

Atmospheric Research

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Section: Introductionmentioning

confidence: 99%

Physico-chemical characterization of PM2.5 in the microenvironment of Shanghai subway

Lü

Liu

Zhang

et al. 2015

Atmospheric Research

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“…Many studies on the O 3 pollution, including satellite data analyses, field experiments and model simulations, have been carried out over China in order to investigate the temporal and spatial characteristics of surface photochemical pollution (Lu and Wang, 2006; H. X. Tu et al, 2007;Zhang et al, 2007Zhang et al, , 2008Geng et al, 2008;Tang et al, 2008Tang et al, , 2009Chen et al, 2009;Han et al, 2011;Ding et al, 2013;Xie et al, 2016b), nonlinear photochemistry of O 3 and its precursors (Lam et al, 2005;Ran et al, 2009;Liu et al, 2010;Li et al, 2011;Xie et al, 2014), interactions between O 3 and aerosols (Lou et al, 2014;Shi et al, 2015), the effects of urbanization on O 3 formation Liao et al, 2015;Li et al, 2016;Xie et al, 2016a;Zhu et al, 2015) and other essential impact factors (Jiang et al, 2012;Li et al, 2012;Wei et al, 2012;Liu et al, 2013;Gao et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Integrated studies of a regional ozone pollution synthetically affected by subtropical high and typhoon system in the Yangtze River Delta region, China

et al. 2016

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Abstract. Severe high ozone (O 3 ) episodes usually have close relations to synoptic systems. A regional continuous O 3 pollution episode was detected over the Yangtze River Delta (YRD) region in China during 7-12 August 2013, in which the O 3 concentrations in more than half of the cities exceeded the national air quality standard. The maximum hourly concentration of O 3 reached 167.1 ppb. By means of the observational analysis and the numerical simulation, the characteristics and the essential impact factors of the typical regional O 3 pollution are comprehensively investigated. The observational analysis shows that the atmospheric subsidence dominated by the western Pacific subtropical high plays a crucial role in the formation of high-level O 3 . The favorable weather conditions, such as extremely high temperature, low relative humidity and weak wind speed, caused by the abnormally strong subtropical high are responsible for the trapping and the chemical production of O 3 in the boundary layer. In addition, when the YRD cities are at the front of Typhoon Utor, the periphery circulation of typhoon system can enhance the downward airflows and cause worse air quality. However, when the typhoon system weakens the subtropical high, the prevailing southeasterly surface wind leads to the mitigation of the O 3 pollution. The integrated process rate (IPR) analysis incorporated in the Community Multi-scale Air Quality (CMAQ) model is applied to further illustrate the combined influence of subtropical high and typhoon system in this O 3 episode. The results show that the vertical diffusion (VDIF) and the gas-phase chemistry (CHEM) are two major contributors to O 3 formation. During the episode, the contributions of VDIF and CHEM to O 3 maintain the high values over the YRD region. On 10-12 August, the cities close to the sea are apparently affected by the typhoon system, with the contribution of VDIF increasing to 28.45 ppb h −1 in Shanghai and 19.76 ppb h −1 in Hangzhou. In contrast, the cities far away from the sea can hardly be affected by the periphery circulation of typhoon system. When the typhoon system significantly weakens the subtropical high, the contribution values of all individual processes decrease to a low level in all YRD cities. These results provide an insight for the O 3 pollution synthetically impacted by the western Pacific subtropical high and the tropical cyclone system.

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“…As mentioned in section 3.1, the high concentration of O3 indicates active atmospheric photochemical reactivity (Li et al, 2012;Seinfeld, 1986), thus, the atmosphere was of strong oxidizing capacity with the presence of large amounts of free radicals (OH, etc.) and ozone, which can promote the formation of secondary aerosols (Pathak et al, 2009;Shi et al, 2015;Wang et al, 2016). As seen in Fig.…”

Section: The Secondary Aerosol Formation Driven By Strong Atmosphementioning

confidence: 99%

“…As ozone pollution is more and more prominent, and the ability of atmospheric oxidation is gradually stronger, the formation mechanism of haze pollution under strong atmospheric oxidization capacity need to be concerned. Previous studies have demonstrated that strong atmospheric photochemical reactions in summer enhanced secondary aerosols formation and led to the synchronous occurrence of high concentrations of PM2.5 and O3 on a regional scale (Pathak et al, 2009;Wang et al, 2016;Shi et al, 2015). Nevertheless, the mechanisms of how overall regional transport, ABL structure, meteorological conditions and the formation of secondary aerosols work together to quantitatively influence the haze pollution under strong atmospheric oxidization capacity in summer remain unclear.…”

Section: Introductionmentioning

confidence: 99%

The haze pollution under strong atmospheric oxidization capacity in summer in Beijing: Insights into the formation mechanism of atmospheric physicochemical process

Zhao¹,

Liu²,

Xin³

et al. 2020

Preprint

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Abstract. Under strong atmospheric oxidization capacity, haze pollution in the summer of Beijing was the result of the synergistic effect of physicochemical process in the atmospheric boundary layer (ABL). The south/southwest areas generally ~&#8201;60&#8211;300&#8201;km far away from Beijing were seriously polluted, in contrast to a clean situation in Beijing. The southerly winds moving more than ~&#8201;20&#8211;30&#8201;km&#8201;h&#8722;1 since early morning primarily caused the initiation of haze pollution. The PM2.5 level increased to 75&#8201;&#956;g&#8201;m&#8722;3 in several hours at daytime, which was simultaneously affected by the ABL structure. Additionally, the O3 concentration was quite high at daytime (250&#8201;&#956;g&#8201;m&#8722;3), corresponding to a strong atmospheric oxidation capacity. Numerous sulfate and nitrate were formed through active atmospheric chemical processes, with sulfur oxidation ratio (SOR) up to ~&#8201;0.76 and nitrogen oxidation ratio (NOR) increasing from 0.09 to 0.26, which further facilitated the particulate matter (PM) level rising. Even so, the increase in sulfate was mainly linked by southerly transport. At midnight, the PM2.5 concentration sharply increased from 75&#8201;&#956;g&#8201;m&#8722;3 to 150&#8201;&#956;g&#8201;m&#8722;3 in 4 hours and stayed the highest level till the next morning. With the premise of an extremely stable ABL structure, the formation of secondary aerosols dominated by nitrate was quite intense, driving the outbreak of haze pollution. PM levels in the south/southeast of Beijing were significantly lower than that in Beijing over this time, even below air quality standards, thus, the contribution of pollution transport was almost gone. With the formation of nocturnal stable boundary layer of 0&#8211;0.3&#8201;km altitude, the extremely low turbulence kinetic energy (TKE) of 0&#8211;0.05&#8201;m2&#8201;s&#8722;2 inhibited the spread of particles and moisture, ending up with elevated levels of PM2.5 and relative humidity (~&#8201;90&#8201;%) near the surface. Under quite high humidity and strong ambient oxidization capacity, the NOR rapidly increased from 0.26 to 0.60 and heterogeneous hydrolysis reactions at the moist particle surface were very significant. The nitrate concentration explosively increased from 11.6&#8201;&#956;g&#8201;m&#8722;3 to 57.8&#8201;&#956;g&#8201;m&#8722;3, while the concentrations of sulfate and organics slightly increased by 6.1&#8201;&#956;g&#8201;m&#8722;3 and 3.1&#8201;&#956;g&#8201;m&#8722;3, respectively. With clean & strong winds passing through Beijing, the stable ABL was broken with potential temperature gradient turning to negative and ABL heights increasing to ~&#8201;2.5&#8201;km. The strong turbulence activity with TKE of ~&#8201;3&#8211;5&#8201;m2&#8201;s&#8722;2 notably promoted the pollution diffusion. The self-cleaning capacity of the atmosphere is always responsible for the dispersion of air pollution. Even so, reducing atmospheric oxidization capacity such as strengthening the collaborative control of nitrogen oxide (NOx) and volatile organic compounds (VOCs) was urgent, as well as continuously deepening regional joint control of air pollution.

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A study of aerosol optical properties during ozone pollution episodes in 2013 over Shanghai, China

Cited by 56 publications

References 52 publications

Physico-chemical characterization of PM2.5 in the microenvironment of Shanghai subway

Physico-chemical characterization of PM2.5 in the microenvironment of Shanghai subway

Integrated studies of a regional ozone pollution synthetically affected by subtropical high and typhoon system in the Yangtze River Delta region, China

The haze pollution under strong atmospheric oxidization capacity in summer in Beijing: Insights into the formation mechanism of atmospheric physicochemical process

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