Multi-year ozone concentration and its spectra in Shanghai, China

Geng, Feng; Mao, Xiaoqin; Zhou, Mingyu; Zhong, Shiyuan; Lenschow, Donald H.

doi:10.1016/j.scitotenv.2015.03.082

Cited by 11 publications

(7 citation statements)

References 40 publications

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“…The observed diurnal patterns of O 3 at SSI and XJH in Fig. 4 were similar to those reported for other sites in eastern China (Xu et al, 2008;Geng et al, 2015;Gao et al, 2017), exhibiting minimums in early morning (06:00-08:00 LST) and maximums in the afternoon (13:00-15:00 LST). However, compared to those at the urban site (XJH), observed amplitudes of O 3 diurnal variations were much smaller at SSI.…”

Section: Regional Transport Characteristics At Ssisupporting

confidence: 88%

A measurement and model study on ozone characteristics in marine air at a remote island station and its interaction with urban ozone air quality in Shanghai, China

Yan²,

et al. 2020

Atmos. Chem. Phys.

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Abstract. To understand the characteristics and changes of baseline ozone (O3) in oceanic air in eastern China, a 6-year measurement of O3 concentration was conducted from 1 January 2012 to 15 September 2017 at a remote offshore station located on Sheshan Island (SSI) near the megacity of Shanghai. The observed monthly mean O3 concentrations at SSI ranged from 33.4 to 61.4 ppbv during the study period, which were about 80 % and 12 % higher, respectively, than those measured at downtown and rural sites in Shanghai. Compared to the remarkable O3 increases observed at urban and rural sites in Shanghai, observed O3 concentrations at SSI exhibited statistically insignificant increasing changes (1.12 ppbv yr−1, α>0.10) during the observation period, suggesting less impacts of anthropogenic emissions on O3 levels in oceanic air. In addition, an insignificant decreasing change (−0.72 ppbv yr−1, α>0.10) was detected in O3 concentrations at SSI in September and October when the influence of regional transport was minimum throughout the year, providing a good proxy to study the baseline oxidation capacity of the oceanic atmosphere. City plumes from Shanghai usually carried higher levels of NOx, resulting in decreased O3 concentrations at SSI during southwesterly and westerly winds. However, In MAM (March–May) and JJA (June–August), due to the enhanced production of oxygenated volatile organic compounds, O3 could be continuously produced during daytime in aged city plumes, resulting in elevated O3 concentrations transported to SSI. The impacts of the offshore O3 on O3 levels in Shanghai are quantified during an easterly wind dominant episode (1–30 September 2014) using the WRF-Chem model (Weather Research and Forecasting model coupled with Chemistry). Sensitivity results suggest that O3 in the oceanic air inflows can lead to 20 %–30 % increases in urban O3 concentrations, which should be crucially considered in dealing with urban O3 pollution in large coastal cities like Shanghai.

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Section: Regional Transport Characteristics At Ssisupporting

confidence: 88%

A measurement and model study on ozone characteristics in marine air at a remote island station and its interaction with urban ozone air quality in Shanghai, China

Yan²,

et al. 2020

Atmos. Chem. Phys.

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“…O 3 also directly corresponds to climate change [ 44 ], as it is related to solar radiation and general atmospheric circulation, which are lower in winter than in sunny summer months. The ozone concentrations were also lower in winter than summer in Shanghai, China [ 45 ].…”

Section: Discussionmentioning

confidence: 99%

Assessment of air quality using a cloud model method

Xu¹,

Xu²

2018

R. Soc. open sci.

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To effectively control air pollution, it is necessary to obtain a preliminary assessment of air quality. The purpose of this study was to introduce a cloud model method in air pollution assessment. First, the standard cloud models of air pollution indicators were obtained, and the calculating process of numerical characteristics employed by the standard cloud model was explained. Second, the levels of air pollution indicators were presented based on the qualitative and quantitative analysis of cloud models, which realized the uncertainty conversion between qualitative concepts and their corresponding quantitative values, as well as taking the fuzziness and randomness into account. Air quality assessment results including SO2, NO2, CO, O3, PM10 and PM2.5 were analysed. Third, the cloud model adopted in the assessment process of air quality was validated by grey relational analysis, and the results confirmed the validity of cloud model assessment. Fourth, the air pollution level of the air quality index (AQI) was determined, and the fuzziness and randomness of the assessment results were thoroughly analysed by taking entropy and hyper entropy into consideration. Fifth, seasonal variations in different air pollution indicators were analysed to proffer a series of recommendations for government policy decision-makers and travellers. The cloud model provided a new method for air quality assessment.

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“…The global O 3 background concentration increased 6−8 and meteorological conditions (e.g., high temperature or more sunlight) could have favored ozone pollution. 9,10 Regulations in China focused on limiting nitrogen oxide (NO x = NO 2 + NO) emissions but neglected volatile organic compound emissions. This change in the mix of anthropogenic emissions could contribute to increasing ozone concentrations 11−13 because it could have shifted the chemical regime from conditions in which ozone production is suppressed by nitrogen oxides to conditions in which the oxidation of organic compounds leads to efficient ozone production.…”

Section: Introductionmentioning

confidence: 99%

No Evidence for a Significant Impact of Heterogeneous Chemistry on Radical Concentrations in the North China Plain in Summer 2014

Tan

Hofzumahaus

et al. 2020

Environ. Sci. Technol.

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The oxidation of nitric oxide to nitrogen dioxide by hydroperoxy (HO 2 ) and organic peroxy radicals (RO 2 ) is responsible for the chemical net ozone production in the troposphere and for the regeneration of hydroxyl radicals, the most important oxidant in the atmosphere. In Summer 2014, a field campaign was conducted in the North China Plain, where increasingly severe ozone pollution has been experienced in the last years. Chemical conditions in the campaign were representative for this area. Radical and trace gas concentrations were measured, allowing for calculating the turnover rates of gas-phase radical reactions. Therefore, the importance of heterogeneous HO 2 uptake on aerosol could be experimentally determined. HO 2 uptake could have suppressed ozone formation at that time because of the competition with gas-phase reactions that produce ozone. The successful reduction of the aerosol load in the North China Plain in the last years could have led to a significant decrease of HO 2 loss on particles, so that ozone-forming reactions could have gained importance in the last years. However, the analysis of the measured radical budget in this campaign shows that HO 2 aerosol uptake did not impact radical chemistry for chemical conditions in 2014. Therefore, reduced HO 2 uptake on aerosol since then is likely not the reason for the increasing number of ozone pollution events in the North China Plain, contradicting conclusions made from model calculations reported in the literature.

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Multi-year ozone concentration and its spectra in Shanghai, China

Cited by 11 publications

References 40 publications

A measurement and model study on ozone characteristics in marine air at a remote island station and its interaction with urban ozone air quality in Shanghai, China

A measurement and model study on ozone characteristics in marine air at a remote island station and its interaction with urban ozone air quality in Shanghai, China

Assessment of air quality using a cloud model method

No Evidence for a Significant Impact of Heterogeneous Chemistry on Radical Concentrations in the North China Plain in Summer 2014

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