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Published on: July 24, 2016
Quantifying interprovincial NO₂ transport over the Yangtze River Delta: Dynamics and drivers
Zhenda Sun1, Zhongfeng Pan2, Nan Zhang3
1School of Environmental Science and Optoelectronic Technology, University of Science and Technology of China, Hefei 230026, China; Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China.
Structural changes in energy and industry are improving air quality in the Yangtze River Delta (YRD). Nitrogen dioxide (NO₂) levels and transport are decreasing, showing that emission mitigation efforts benefit the entire region.
Area of Science:
- Atmospheric chemistry and air quality
- Environmental science and policy
- Remote sensing and data integration
Background:
- The Yangtze River Delta (YRD) is undergoing significant structural transitions in its energy and industrial sectors.
- These transitions are impacting regional air quality, necessitating an understanding of pollutant dynamics.
- Nitrogen dioxide (NO₂) is a key air pollutant influenced by industrial and energy-related emissions.
Purpose of the Study:
- To quantify interprovincial nitrogen dioxide (NO₂) fluxes within the Yangtze River Delta (YRD).
- To analyze trends in NO₂ column concentrations and surface concentrations across the YRD.
- To evaluate the impact of structural emission mitigation on regional air quality and pollutant transport.
Main Methods:
- Utilized a closed-loop integration method combining data from TROPOMI, ERA5, and GEOS-CF satellite and reanalysis datasets.
- Quantified regional NO₂ column concentrations and analyzed their annual decline rates.
- Assessed interprovincial NO₂ fluxes and trends in transport patterns across different segments of the YRD.
Main Results:
- Regional NO₂ column concentrations declined by (-3.16 ± 1.08)%/yr, with significant decreases in Anhui and Jiangsu.
- NO₂ transport weakened, showing a net influx in the western YRD (3.29 kg/s) and a net efflux in the eastern YRD (15.25 kg/s).
- Surface NO₂ concentrations in major cities decreased by (-3.54 ± 0.45)%/yr to (-6.1 ± 0.31)%/yr, with Suzhou and Nanjing showing the steepest declines.
Conclusions:
- Synchronous declines in surface and column NO₂ concentrations, alongside weakening transport fluxes, demonstrate the effectiveness of structural emission mitigation.
- Air quality benefits are achievable across administrative boundaries through regional atmospheric circulation.
- Coordinated structural transitions in industrial and energy sectors are crucial for sustainable air quality improvements in megaregions like the YRD.
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