11 Feb 2021

11 Feb 2021

Review status: a revised version of this preprint is currently under review for the journal ESSD.

Catalog of NOx emissions from point sources as derived from the divergence of the NO2 flux for TROPOMI

Steffen Beirle1, Christian Borger1, Steffen Dörner1, Henk Eskes2, Vinod Kumar1, Adrianus de Laat2, and Thomas Wagner1 Steffen Beirle et al.
  • 1Max-Planck-Institut für Chemie (MPI-C), Mainz, Germany
  • 2Koninklijk Nederlands Meteorologisch Instituut (KNMI), De Bilt, Netherlands

Abstract. We present version 1.0 of a global catalog of NOx emissions from point sources, derived from TROPOMI measurements of tropospheric NO2 for 2018–2019. The identification of sources and quantification of emissions are based on the divergence (spatial derivative) of the mean horizontal flux, which is highly sensitive for point sources like power plant exhaust stacks.

The catalog lists 451 locations which could be clearly identified as NOx point source by a fully automated algorithm, while ambiguous cases as well as area sources such as Megacities are skipped. 242 of these point sources could be automatically matched to power plants. Other NOx point sources listed in the catalog are metal smelters, cement plants, or industrial areas. The four largest localized NOx emitters are all coal combustion plants in South Africa. About 1/4 of all detected point sources are located in the Indian subcontinent and are mostly associated with power plants.

The catalog is incomplete, mainly due to persisting gaps in the TROPOMI NO2 product at some coastlines, inaccurate or complex wind fields in coastal and mountainous regions, and high noise in the divergence maps for high background pollution. The derived emissions are generally too low, lacking a factor of up to 2, mainly due to a low bias of TROPOMI NO2 columns.

Still, the catalog has high potential for checking and improving emission inventories, as it provides accurate and independent up-to-date information on the location of sources of NOx, and thus also CO2.

The catalog of NOx emissions from point sources is freely available at (Beirle et al., 2020).

Steffen Beirle et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Review of essd-2020-280', Anonymous Referee #1, 03 Mar 2021
  • RC2: 'Comment on essd-2020-280', Anonymous Referee #2, 16 Apr 2021

Steffen Beirle et al.

Data sets

Quantification of NOx point sources from TROPOMI Beirle, S., Borger, C., Dörner, S., Eskes, H., Kumar, V., de Laat, A., and Wagner, T.

Steffen Beirle et al.


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Short summary
A catalog of point sources of Nitrogen oxides was created using satellite observations of NO2. Key for the identification of point sources was the divergence, i.e. the difference between upwind and downwind levels of NO2. The catalog lists 451 locations, of which 242 could be automatically matched to power plants. Other point sources are metal smelters, cement plants, or industrial areas. The catalog thus allows checking and improving of existing emission inventories.