News

New Publication: NOx emissions changes from 2019 to 2021 in Eastern China as estimated through variational inversions and TROPOMI satellite data

We investigate changes in air pollution from nitrogen oxides NOx (=NO+NO2) across Eastern China from 2019 to 2021, using a satellite-based modelling approach. Our results show a drop in pollution in 2020 in most provinces, and along the China-Mongolia-Russia Economic Corridor. The analysis also captures emission variations during the Lunar New Year. By estimating emissions at the provincial level, the study provides insights into how major events and policy measures influence local air quality.

Abeed, R., Fortems-Cheiney, A., Broquet, G., Plauchu, R., Pison, I., Berchet, A., Potier, E., Zheng, B., Dufour, G., Coman, A., Savas, D., Siour, G., Eskes, H., Revilla-Romero, B., Delavois, A., and Ciais, P.: NOx emissions changes from 2019 to 2021 in Eastern China as estimated through variational inversions and TROPOMI satellite data, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2025-3329, 2025.

World Emission present at the ESA “Showcasing Space Applications for Maritime Decarbonisation” event

The European Space Agency (ESA) hosted on 19th November 2025 an event highlighting the role of space technologies in advancing maritime decarbonisation at ESTEC in the Netherlands – the technical heart of ESA.          

This one-day programme presented the latest developments emerging from ESA’s maritime decarbonisation call, featuring fast-pitch presentations, networking slots, and opportunities to explore future collaboration.

The agenda was structured around five key themes:

  • Digitalisation
  • Alternative Fuels and Propulsion Systems
  • Ports
  • Emissions Monitoring
  • Automation

Steffen Beirle (MPIC), Scientific coordinator of the ESA World Emission Work Package on Maritime Emissions, presented on the “Emissions Monitoring” session. Steffen’s feedback on the event:

“The event was quite interesting, with many different facets of current developments in the maritime sector. On the Emissions Monitoring session, while the potential of satellite measurements for emission monitoring was clear, the World Emission presentation was one of the few ones showing actual satellite measurements for maritime emissions monitoring. This demonstrated the added value of this new activity included within the World Emission project.”

ESA World Emission at the ESA Living Planet Symposium 2025

During the ESA LPS conference, the World Emission team showcased two presentations at the Advancing Air Quality Monitoring from Space Session (part 1 and part 2) on Thursday 26th June 2025.

First, Grégoire Broquet (LSCE), ESA’s World Emission Scientific Leader, provided the audience with the detailed framework of the World Emission service and its latest updates. Gregoire also explained the status of the added value and readiness of “top-down” (inversion-based) emission inventories for continents, countries, and regional or local emission hot spots derived from Earth Observation. In part 2 of the session, Steffen Beirle (MPIC) presented the work on “Impact of wind fluctuations on the performance of the divergence method: How steady is the state?” on NOx emissions. Other team members that joined at the LPS were Beatriz Revilla-Romero (Project Coordinator) and Bruno Franco (ULB).

The World Emission presentation can be accessed here and Beirle’s presentation on NOx here. 



ESA World Emission’s 4th User Workshop: A Successful Event


The workshop, held on January 31, 2025, in hybrid mode at ESA HQs in Paris and online, featured:

  • Over 100 participants from various organizations, including National Inventories Agencies (Spain, France, Netherlands, Germany and Cyprus), Copernicus ECMWF, DG Clima, the European Environment Agency, research and commercial organisations.
  • Key presentations from experts like Christian Mielke, Beatrice Ellerhoff, and Hannes Witt, among other key experts highlighting advancements in GHG and air quality monitoring.
  • Collaborative discussions on integrating EO into operational practices for monitoring emissions.

This event marked a significant step forward in discussions on how Earth observation can contribute to the global effort to monitor and reduce greenhouse gas emissions.

GMV, as the event organisers, would like to thank all the teams from the involved entities.
ESA: Antony Delavois Christian Retscher Yasjka Meijer Claire MacIntosh Giuseppe Ottavianelli
+ ESA #SEF and ESA #EO_ASCENT project teams!

Speakers: Christian Mielke, Beatrice Ellerhoff, Hannes Witt, Mélanie Juillard, Javier Pérez-Ilzarbe, Nicoletta Kythreotou, Gorka M. and Richard Engelen

and all #WorldEmission  consortium, GMV, Laboratoire des Sciences du Climat et de l’Environnement, Kayrros, Science Partners, Max-Planck-Institut für Chemie, Barcelona Supercomputing Center, The Cyprus Institute and Citepa with hightlights from Gregoire Broquet (LSCE), Srivatsan Anand (KAYRROS) and Marc Guevara Vilardell (BSC).

Presentations are available here:


Publication: Satellite-Based Identification of Large Anthropogenic NMVOC Emission Sources (ULB, Franco et al., 2024)

Nonmethane volatile organic compounds (NMVOCs) emitted in excess from anthropogenic sources significantly contribute to the formation of harmful pollutants, thereby degrading air quality. While satellite measurements have become valuable tools for tracking anthropogenic emitters, they have primarily targeted inorganic species and methane (CH4). This study demonstrates the potential of infrared atmospheric sounding interferometers (IASI) to detect anthropogenic NMVOC point sources on a global scale. Using an advanced oversampling technique, we enhance the spatial resolution of IASI measurements to identify emitters of three major NMVOCs: methanol (CH3OH), acetylene (C2⁢H2), and propylene (C3⁢H6). These point sources are primarily associated with chemical and petrochemical facilities, coal-burning activities, metallurgy, pharmaceutical manufacturing sites, and megacities. We also highlight the value of combining IASI measurements of NMVOCs with those of the inorganic species, such as sulfur dioxide (SO2) and ammonia (NH3), to aid in the identification of anthropogenic point sources.

Franco, B., Clarisse, L., Van Damme, M., Hadji-Lazaro, J., Clerbaux, C., & Coheur, P. (2024). Satellite-based identification of large anthropogenic NMVOC emission sources. Journal of Geophysical Research: Atmospheres, 129, e2024JD042047. https://doi.org/10.1029/2024JD042047

Publication: A new method for estimating megacity NOx emissions and lifetimes from satellite observations (MPIC, Beirle and Wagner, 2024)

We present a new method for estimating NOx emissions and effective lifetimes from large cities based on NO2 measurements from the TROPOspheric Monitoring Instrument (TROPOMI) (PAL dataset, May 2018–November 2021). As in previous studies, the estimate is based on the downwind plume evolution for different wind directions separately. The novelty of the presented approach lies in the simultaneous fit of downwind patterns for opposing wind directions, which makes the method far more robust (i.e., less prone to local minima with nonphysically high or low lifetimes) than a single exponential decay fit. In addition, the new method does not require the assumption of a city being a “point source” but also derives the spatial distribution of emissions.

The method was successfully applied to 100 cities worldwide on a seasonal scale. Fitted emissions generally agree reasonably with the Emissions Database for Global Atmospheric Research (EDGAR) v6 (R=0.72) and are on average 14 % lower, while estimated uncertainties are still rather large (≈ 30 %–50 %). Lifetimes were found to be rather short (2.44 ± 0.68 h) and show no distinct dependency on season or latitude, which might be a consequence of discarding observations at high solar zenith angles (>65°).

The main limitations of this and similar methods are the underlying assumptions of steady state (meaning constant emissions, wind fields and chemical conditions) within about 100 km downwind from a city, which is probably a simplification that is too strong in order to reach higher accuracies.

Beirle, S. and Wagner, T.: A new method for estimating megacity NOx emissions and lifetimes from satellite observations, Atmos. Meas. Tech., 17, 3439–3453, https://doi.org/10.5194/amt-17-3439-2024, 2024.

Continuation of ESA World Emission to support global GHG and Air pollution monitoring from satellite data.

In October 2024 ESA World Emission has entered a new 2-year phase (#3) in which the consortium will primarily: 

  • Continue and improve the current World Emission service and products 
  • Demonstrate that EO-based GHG and air pollutants top-down inventories can support countries’ s reports 
  • Enhance Stakeholder Engagement, as well as synergies & service assessments  
  • Include developments in two new areas: Maritime Emissions and Methane R&D. 

This will allow the continuation of the services provided which initially in March 2022.  

On this new phase, the consortium maintains its core members: GMV, LCSE, KAYRROS, MPIC, ULB, BSC and The Cyprus Institute, as well as incorporating two new members: Science Partners and Citepa. 

Stay tuned for one of the first key events: the next Stakeholder Workshop which will be an in-person event (+hybrid) on 30th January 2025 and hold at ESA’s HQ location in Paris (invitation-only event for in-person participants). The objectives of this workshop will be to: 

  • Present the World Emission Phase 3 tasks and objectives to the stakeholders.
  • Organize a co-design workshop where the stakeholders’ requirements can be discussed and integrated to the World Emission Phase 3, when possible. 
  • Allow inverse modellers to explain their modelling / inverse modelling frameworks used in World Emission. 


The World Emission project at the 3rd Annual Scientific Workshop on Climate and Atmosphere Research & Innovation in the Eastern Mediterranean and Middle East (EMME) region

Latest updates of the World Emission Project, relevant to policy-oriented end users, were presented at the 3rd annual scientific workshop on Climate and Atmosphere Research & Innovation in the Eastern Mediterranean and Middle East (EMME) region, which took place online on 7 November, 2023.

Dr Jonilda Kushta, a research scientist at CARE-C of the Cyprus Institute, who leads the team of the CyI researchers contributing to the World Emission project, delivered a VPICO presentation entitled ‘Validating National Emission Inventories with Satellite- Derived Estimates:  Case study for Cyprus’. Dr Kushta presented a few World Emission research components that, within the context of the project, can be beneficial for the validation of the emission fluxes of greenhouse gases and air pollutants.  Cyprus was used as a case study in order to validate the inversion of CO2 and NOx emission fluxes against the nationally reported emission inventories.

The workshop was a great success with the participation of more than 340 scientists, researchers, students and industry professionals, in the area of research & innovation on climate change and air pollution, from over 50 countries in the EMME region. Additionally, 22 oral (including 3 keynote speakers) and 34 VPICO presentations were delivered by representatives of universities, research institutions and private companies, actively engaged in the topics of air pollution and research innovations related to climate change.

You can find more about the workshop here.

New scientific paper and dataset on NOx point source emissions published by World Emission partner MPIC!

We present an updated (v2) catalog of NOx emissions from point sources as derived from TROPOspheric Monitoring Instrument (TROPOMI) measurements of NO2 (Products Algorithm Laboratory (PAL) product) combined with wind fields from ERA5. Compared to version 1 of the catalog (Beirle et al., 2021), several improvements have been introduced to the algorithm. Most importantly, several corrections are applied, accounting for the effects of plume height on satellite sensitivity, 3D topographic effects, and the chemical loss of NOx, resulting in considerably higher and more accurate NOx emissions. In addition, error estimates are provided for each point source, taking into account the uncertainties of the individual retrieval steps.

The v2 catalog is based on a fully automated iterative detection algorithm of point sources worldwide. It lists 1139 locations that have been found to be significant NOx sources. The majority of these locations match power plants listed in the Global Power Plant Database (GPPD). Other NOx point sources correspond to cement plants, metal smelters, industrial areas, or medium-sized cities.

The emissions listed in v2 of the catalog show good agreement (within 20 % on average) to emissions reported by the German Environment Agency (Umweltbundesamt, UBA) as well as the United States Environmental Protection Agency (EPA). The data are publicly available at https://doi.org/10.26050/WDCC/No_xPointEmissionsV2 (Beirle et al., 2023).

Open-access of the published paper on Earth Science Data journal on https://essd.copernicus.org/articles/15/3051/2023/

World Emission passed to Phase 2 for the full service implementation!

Clean air is of vital importance for our health and for the environment. Greenhouse gases emissions are also one of the factors responsible for climate change. GMV is proud of the work that its team is contributing to the World Emission project, which is focused on improving emission inventories by using measurements collected by satellites.

This project began in 2022, and it is divided into two phases, each lasting for one year. The first phase has now been completed, and one of the team’s most recent accomplishments has been obtaining the European Space Agency’s approval for initiation of the second phase.

GMV is the leader of the World Emission project, and it is also acting as its technology integrator. The GMV team is overseeing the general technical coordination of seven organizations: LSCE, KAYRROS, Capgemini, MPIC, ULB, BSC, and CYI. In addition, GMV is responsible for designing the validation plan, which is a key aspect for comparing the satellite data with measurements taken from Earth. For the full project, GMV is also in charge of the communications work package, stakeholder participation, and user requirements. This includes organizing international workshops focused on encouraging the use of what is known top-down  emission inventories, by using satellite measurements to complement the traditional bottom-up approach.

Currently, World Emission is working with different atmospheric gases at a variety of scales: from localized sources to regional and worldwide production at an unprecedented scale. All of these data sets are being integrated into a single online portal. This is being made freely available to the public, as a way of encouraging the use of emission inventory information analyzed based on satellite data.

One of the first challenges the consortium had to confront was the need to organize an international workshop just seven weeks after the project began.  Another challenge for the consortium was the difficult work of creating the World Emission portal within a period of only nine months. The team is also now deeply involved in the work required to implement the complete service and validate the final products.

It is expected that the final version of the online portal will be ready in December 2023, and the workshop for the project’s stakeholders will take place during the first months of 2024. You won’t want to miss it!