Analyzing nitrogen dioxide to nitrogen oxide scaling factors for data-driven satellite-based emission estimation methods: A case study of Matimba/Medupi power stations in South Africa

  • Janne Hakkarainen*
  • , Gerrit Kuhlmann
  • , Erik Koene
  • , Diego Santaren
  • , Sandro Meier
  • , Maarten C. Krol
  • , Bart J.H. van Stratum
  • , Iolanda Ialongo
  • , Frédéric Chevallier
  • , Johanna Tamminen
  • , Dominik Brunner
  • , Grégoire Broquet
  • *Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

In this paper, we propose improved nitrogen dioxide (NO2) to nitrogen oxide (NOx) scaling factors for several data-driven methods that are used for the estimation of NOx power plant emissions from satellite observations of NO2. The scaling factors are deduced from high-resolution simulations of power plant plumes with the MicroHH large-eddy simulation model with a simplified chemistry and then applied to Sentinel-5 Precursor (S5P) TROPOspheric Monitoring Instrument (TROPOMI) NO2 satellite observations over the Matimba/Medupi power stations in South Africa. We show that due to the non-linear chemistry the optimal NO2 to NOx scaling factors depend on both the method employed and the specific segments of the plume from which emission estimate is derived. The scaling factors derived from the MicroHH simulations in this study are substantially (more than 50%) higher than the typical values used in the literature with actual NO2 observations. The results highlight the challenge in appropriately accounting for the conversion from NO2 to NOx when estimating point source emissions from satellite NO2 observations.

Original languageEnglish
Article number102171
Number of pages11
JournalAtmospheric Pollution Research
Volume15
Issue number7
DOIs
Publication statusPublished - Jul 2024

Bibliographical note

Publisher Copyright:
© 2024 Turkish National Committee for Air Pollution Research and Control

Funding

Most of the work performed in this paper was done in the framework of EU H2020 project CoCO2 (Grant No. 958927). The FMI team also acknowledge additional funding from the Research Council of Finland (Grant Numbers 353082, 357904, 359196, 359455 and 331829). The Copernicus Sentinel-5P/TROPOMI data used in this work are provided as part of the Sentinel-5P Product Algorithm Laboratory (S5P-PAL).

FundersFunder number
Research Council of Finland353082, 359455, 331829, 357904, 359196
Horizon 2020 Framework Programme958927

    Keywords

    • Emission estimation
    • MicroHH
    • Nitrogen dioxide
    • Nitrogen oxides
    • Plume inversion
    • Power station
    • Satellite data
    • Sentinel-5P
    • TROPOMI

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