Examining the implications of photochemical indicators on the O<sub>3</sub>-NO<sub>x</sub>-VOC sensitivity and control strategies: A case study in the Yangtze River Delta (YRD), China

Li, Xun; Qin, Momei; Li, Lin; Gong, Kangjia; Shen, Huizhong; Li, Jingyi; Hu, Jianlin

doi:10.5194/acp-2022-493

Cited by 2 publications

(2 citation statements)

References 29 publications

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“…Those could explain why the NO 2 reduction during that period could aggravate the O 3 pollution [44]. Most areas verified to be NOx-limited regimes in YRD during summertime could also be found in Li et al [45]. Furthermore, effects from ∆O 3 calculation with meteorological conditions regression and short-term (2018-2021) observations from satellite on the sensitivity analysis have not been evaluated in study.…”

Section: Sensitivity Of the O 3 To No 2 Reduction Inferred From Dense...mentioning

confidence: 93%

Ozone Pollution and Its Response to Nitrogen Dioxide Change from a Dense Ground-Based Network in the Yangtze River Delta: Implications for Ozone Abatement in Urban Agglomeration

Gao

et al. 2022

Atmosphere

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Understanding the response of tropospheric ozone (O3) to nitrogen dioxide (NO2) change is important for local O3 control. The relationship between O3 and NO2 at county scale in China has been extensively studied using models, but there is a lack of results from direct measurements. In this study, we used measurements of O3, NO2 and meteorological conditions from a dense network in the Yangtze River Delta (YRD), and satellite observed formaldehyde (HCHO) and NO2 column densities for the analysis of O3 variabilities and its relationship to NO2. As a result, severe O3 pollution occurred mainly in Shanghai city, southern Jiangsu and northern Zhejiang provinces in YRD during April–September. In addition, meteorological conditions could explain 54% the diurnal O3 variation over YRD. During April–September 2015–2021, O3 showed a significant positive relationship (r = 0.61 ± 0.10) with NO2 after removing the impact from meteorological conditions. However, the relationship could be reversed with NO2 concentration change. Our result suggested that the controllable O3 related to NO2 change is up to 100 μg·m−3 in megacities over Shanghai and northern Zhejiang province. The O3 is much more sensitive to the NO2 reduction in megacities than surrounding areas. Our results evaluate the different impacts of NO2 changes on O3 formation, which provides explanation for the simultaneously alleviated O3 pollution and reduced NO2 in 2020 in Shanghai and northern Zhejiang, as well as the increased O3 in most counties before 2019 with reduced NO2 during October–March. The driving mechanism as revealed from this study for O3 and NO2 will be valuable for the O3 abatement through NO2 reduction at sub-county scale over YRD in China.

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Section: Sensitivity Of the O 3 To No 2 Reduction Inferred From Dense...mentioning

confidence: 93%

Ozone Pollution and Its Response to Nitrogen Dioxide Change from a Dense Ground-Based Network in the Yangtze River Delta: Implications for Ozone Abatement in Urban Agglomeration

Gao

et al. 2022

Atmosphere

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“…A higher ΔH 2 O 2 /ΔHNO 3 ratio indicates a NO x -limited regime, while a lower ΔH 2 O 2 /ΔHNO 3 ratio corresponds to a VOC-limited regime. There are other indicators for determining the NO x /VOC-limited regimes that are discussed in the literature (Li et al, 2022). However, here we use the ΔH 2 O 2 /ΔHNO 3 ratio as is used in the CAMx model (Ramboll Environment and Health, 2020).…”

Section: Ozone (O 3 )mentioning

confidence: 99%

Impacts of maritime shipping on air pollution along the U.S. East Coast

Golbazi

Archer

2023

Preprint

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Abstract. Air pollution is considered a leading threat to human health in the United States (U.S.) and worldwide. An important source of air pollution in coastal areas is the globally increasing maritime shipping traffic. In this study, we take a high-resolution modeling approach to investigate the impacts of ship emissions on concentrations of various atmospheric pollutants, under the meteorological conditions and emissions of the year 2018. We utilize the Comprehensive Air Quality Model with extensions (CAMx) to simulate transport, diffusion, and chemical reactions, and the Weather Research and Forecasting (WRF) model to provide the meteorological inputs. We focus on four criteria pollutants – fine particulate matter with a diameter smaller than 2.5 μm (PM2.5), nitrogen dioxide (NO2), sulfur dioxide (SO2), and ozone (O3) – as well as nitrogen oxide (NO), and we calculate their concentrations in the presence and absence of the ship emissions along the U.S. East Coast, particularly in the proximity of major ports. We find that ship emissions increase the PM2.5 concentrations over the ocean and sparse areas inland. The 98-th percentile of the 24-hour average PM2.5 concentrations (the "design value'' used by the U.S. Environmental Protection Agency) increased by up to 3.2 μm m−3 in some coastal areas. In addition, ships contribute significantly to SO2 concentrations, up to 95 % over the Atlantic and up to 90 % over land in coastal states, which represents a ~45 ppb increase in the SO2 design values in some states. The 98-th percentile of the hourly NO2 concentrations also increased by up to 15 ppb at the major ports and along the shore. In addition, we find that the impact of shipping emissions on O3 concentrations is not uniform, meaning that ships affect ozone pollution in both positive and negative ways. Over the ocean, O3 concentrations were significantly higher in the presence of ships, but in major coastal cities, O3 concentrations decreased in the presence of ships. Our simulation results show that ships emit significant amounts of fresh NO in the atmosphere, which then helps scavenge O3 in VOC-limited areas, such as major ports. By contrast, over the ocean (NOx-limited regime), enhanced NOx (NO2 + NO) concentrations due to ships contribute to the formation of O3 and therefore enhance O3 concentrations. Overall, due to the dominant southwesterly wind direction in the region, the impacts of ships on air pollutants mainly remain offshore. However, in coastal states near major ports, the impacts are significantly important.

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Examining the implications of photochemical indicators on the O₃-NO_x-VOC sensitivity and control strategies: A case study in the Yangtze River Delta (YRD), China

Cited by 2 publications

References 29 publications

Ozone Pollution and Its Response to Nitrogen Dioxide Change from a Dense Ground-Based Network in the Yangtze River Delta: Implications for Ozone Abatement in Urban Agglomeration

Ozone Pollution and Its Response to Nitrogen Dioxide Change from a Dense Ground-Based Network in the Yangtze River Delta: Implications for Ozone Abatement in Urban Agglomeration

Impacts of maritime shipping on air pollution along the U.S. East Coast

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Examining the implications of photochemical indicators on the O3-NOx-VOC sensitivity and control strategies: A case study in the Yangtze River Delta (YRD), China

Cited by 2 publications

References 29 publications

Ozone Pollution and Its Response to Nitrogen Dioxide Change from a Dense Ground-Based Network in the Yangtze River Delta: Implications for Ozone Abatement in Urban Agglomeration

Ozone Pollution and Its Response to Nitrogen Dioxide Change from a Dense Ground-Based Network in the Yangtze River Delta: Implications for Ozone Abatement in Urban Agglomeration

Impacts of maritime shipping on air pollution along the U.S. East Coast

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Examining the implications of photochemical indicators on the O₃-NO_x-VOC sensitivity and control strategies: A case study in the Yangtze River Delta (YRD), China