GEIA 2023


20th GEIA Conference

Towards mitigating air pollutant and greenhouse gas emissions

21-23 June 2023

Hosted by the Royal Belgian Institute for Space Aeronomy Belgium

The Global Emissions InitiAtive (GEIA) provides stability in a rapidly changing world, by ensuring access to emissions data, facilitating emissions analyses, and strengthening the global community of emissions stakeholders. GEIA is a trusted source of the emissions information needed to address some of society’s greatest challenges. 

GEIA’s 20th Conference focused on advancing the scientific basis of emissions understanding needed to more effectively mitigate air pollutant and greenhouse gas emissions. The Conference brough  together the latest research on emissions from all sectors and discussed the impacts of changing emissions on air quality and climate. The conference highlightrd the activities of GEIA’s Working Groups and GEIA’s collaborations with other international groups. The conference also solicited input from the community about GEIA’s path forward by involving experts from all over the world. 

The Conference had 4 themes:

1.     Anthropogenic and natural emissions from local to global

2.     Top-down Emissions & Satellite Analyses

3.     Integrated studies of air pollutant and greenhouse gas emissions

4.     Mitigation efforts including real world examples

GEIA Executive Committee: Cathy Liousse, Brian McDonald, Paulette Middleton, Claire Granier

Local Organizing Committee: Trissevgeni Stavrakou, Yasmine Sfendla, Beata Opacka





20th GEIA Conference - Towards mitigating air pollutant and greenhouse gas emissions 

21-23 June 2023    Royal Museums of Fine Arts of Belgium, Brussels

Main Organizers

  • Cathy Liousse, Laboratoire d’Aérologie, Université de Toulouse, CNRS, UPS, France

  • Brian Mc Donald, National Oceanic and Atmospheric Administration (NOAA), USA,

  • Paulette Middleton, Panorama Pathways, USA

  • Claire Granier, (1) Laboratoire d’Aérologie, Université de Toulouse, CNRS, UPS France;

    (2) NOAA USA and (3) CIRES, University of Colorado Boulder, Boulder, USA

  • Trissevgeni Stavrakou, Belgian Institute for Space Aeronomy, Belgium,

    Sponsors – NASA, IGAC, NOAA, Royal Society of Chemistry
    Hosts – Royal Belgian Institute for Space Aeronomy, Belgian Climate Center, Museums of Fine Arts


    153 Researchers Total including 62 Young Researchers
    31 Countries (Argentina, Austria, Bangladesh, Belgium, Brazil, Canada, Chile, China, Colombia, Czech Republic, Denmark, Egypt, France, Germany, Greece, India, Italy, Ivory Coast, Japan, Kenya, Mexico, Netherlands, Norway, Portugal, South Korea, Spain, Sweden, Switzerland, Thailand, United Kingdom, United States.)

    Science Summary

    The international GEIA program includes researchers working on the science of emissions -- a gateway to studies of air quality, health and climate change. GEIA’s goals are to (1) Promote broad and consistent access to emissions information, (2) Build the scientific basis for emissions data by enhancing analysis of emissions processes and (3) Strengthen the community of emissions stakeholder groups.

    This 20th GEIA conference -“Towards the reduction of emissions of air pollutants and greenhouse gases”- included four themes: (1) Anthropogenic and natural emissions from local to global, (2) Top-down Emissions & Satellite Analyses, (3) Integrated studies of air pollutant and greenhouse gas emissions, and (4) Mitigation efforts including real world examples.     A special session discussed GEIA Working Groups opportunities and next steps. A Town Hall provided lively interactive breakout session discussions on how GEIA can best support decision making processes and best organize to support mitigation of air pollution and greenhouse gases. Finally, a demonstration of ECCAD website (the GEIA portal providing data access and tools for data analysis) showed the emerging capabilities for displaying and analyzing emissions data.

With 32 oral presentations and 112 posters, the conference was rich in information, innovative scientific results, debates, and perspectives. Two poster prizes were awarded to two early career scientists: Megan He (Yale University) and Glenn-Michael Oomen (BIRA-IASB). The conference highlighted the intense GEIA activities on developments of bottom-up global/national/regional anthropogenic emission inventories, a growing interest in both biogenic and anthropogenic urban emission inventories, and a few innovative emission studies on less-known pollutants and sources. The conference also brought into focus these needs: to constrain emissions through modeling, better characterize source emissions from measurements, and continue to reduce emissions uncertainties.

The conference showed an increasing number of “top-down” emissions studies since the last GEIA conference. This was in part thanks to the coordination of the conference with the AMIGO IGAC activity workshop. These presentations and posters demonstrated the promise of satellite-inferred emissions as a check on bottom-up emission inventories. The conference underlined the importance of recognizing challenges related to satellite observation and model errors when inferring emissions. A future goal is to move towards multi-species / sectoral emissions inversions especially with next-generation geostationary observations.

The conference also pointed out the interest of GEIA to develop integrated studies of air pollutants and greenhouse gas emissions. With a good spread in research across continents, the presenting studies showed how the multispecies analysis can be beneficial for quantifying AQ / GHG co-benefits, the inference of fossil CO2, and source attribution. The integrated emission inventories provide potential for mitigation, and baselines for predictions and projections.

An important question raised deals with the responsibility of scientists to engage with stakeholders. The last theme of the conference presented GEIA community mitigation efforts including: the need of better targeting and documenting the different sectors of activities and their relative emissions as a first step for possible mitigations; the development of mitigation tools to support efficient mitigation strategy design; and estimates of mitigation actions’ impacts on air quality, health and climate.

In the years ahead, GEIA will continue its mission to improve emissions understanding in dealing with issues around megacity air pollution, regional and international air quality, and long-term climate change. The GEIA working groups, central to addressing these challenges, will be expanding to better incorporate regional (Asia, Africa, Latin America/Caribbean) and urban analyses.



Auditorium 490, Fine Arts Museum, Museumplein, Rue du Musée 9, 1000, Brussels,4.3563547,19z/data=!4m6!3m5!1s0x47c3c5d82b04be77:0xaaaad99edb65d248!8m2!3d50.8424479!4d4.3570035!16s%2Fg%2F11h00d4z33?entry=ttu



Photo of Venue and Map of Venue Location




AMIGO Workshop

June 19-20, Brussels

AMIGO Workshop occurred right before the GEIA 2023 Conference.