Global Anthropogenic Emissions Inventory of Hydrogen and Air Pollutants

This dataset corresponds to deliverable “D2.2 – H2 emission inventory” from the Working Package II – Leakages and Emissions, part of the Climate impacts of a HYdrogen economy: the pathWAY to knowledge (HYway) project.   Version: v1.0  Release date: 28 February 2026  License: Creative Commons Attribution 4.0 International (CC BY 4.0)  The HYway project has received funding from the European Union’s Horizon Europe Research and Innovation Programme under Grant Agreement No. 101137582. Views and opinions expressed are however those of the authors only and do not necessarily reflect those of the European Union or CINEA. Neither the European Union nor the granting authority can be held responsible for them.    Dataset Description  This dataset provides a global, gridded inventory of past and present-day anthropogenic hydrogen (H₂) emissions at a spatial resolution of 0.1° × 0.1°, and monthly temporal resolution. Emissions are reported in kilograms of pollutant per square meter per second (kg/m²/s). Data are provided in NetCDF format, along with a summary file presenting detailed (GAINS regions), aggregated (IEA/WEO regions) and global totals by key sectors.    The dataset includes the following pollutants:  Hydrogen (H₂)  Carbon monoxide (CO)  Ammonia (NH₃)  Nitrogen oxides (NOₓ)  Fine particulate matter (PM₂.₅)  Sulfur dioxide (SO₂)  Volatile organic compounds (VOC)*  *This version reports total VOC emissions only. Future releases will provide speciated emissions.  The sectors for which gridded data are provided (might vary by pollutant, i.e. some layers will be missing) include:  Energy sector  Residential combustion (cooking and heating)  Transportation  Industry (combustion and processes)  Solvent use  Waste management  Agriculture (livestock and fertilizer application)  Open burning of agricultural residues  International shipping  Methodology  Emissions and spatial gridding were estimated using the Greenhouse Gas–Air Pollution Interactions and Synergies (GAINS) modelling framework (Amann et al. 2011), developed by the International Institute for Applied Systems Analysis (IIASA). Estimates are provided for the years 2000, 2005, 2010, 2015 and 2019 and 2025. Emissions for 2020 are not included, as the COVID-19 pandemic led to atypical patterns in energy consumption and associated emissions, making the year unrepresentative for trend analysis and baseline comparisons.  The inventory includes emissions from anthropogenic land-based sources and from national and international shipping but excludes international aviation. Emissions from open burning of biomass cover the burning of agricultural residues only and do not include emissions from forest, peat, or savannah fires. Hydrogen emissions from those sources can be estimated by emission factors and H2/CO ratios provided by Andreae (2019), Ouyang et al. (2025) and Paulot et al. (2024).  In addition to the traditional activities and sectors modelled within GAINS, this dataset incorporates new emission sources defined under the hydrogen module:  H₂ emissions from incomplete combustion and leakages; NOₓ emissions from hydrogen combustion and hydrogen production;  NH₃ emissions from hydrogen storage and handling;  CO, NOx, PM₂.₅, SO₂ and VOC emissions from hydrogen production;  Activity Data and Assumptions  Emission estimates are based on historical activity data from the International Energy Agency’s World Energy Outlook (IEA/WEO 2025) and from international industrial statistics. Waste, VOC-related activities, and agricultural activities originate from the LRTAP_Baseline_v7 scenario within the GAINS framework (Klimont et al. 2025).  The estimates account for emission control strategies, policies, and technologies implemented under country-specific Current Legislation (CLE) scenarios aimed at reducing air pollutants and greenhouse gas emissions.  For hydrogen production, this inventory assumes a current technology mix dominated by fossil fuels (natural gas, coal, and oil), while the electrolysis powered by clean and renewable energy sources contributes approximately 1% of total production.  References Amann, Markus, Imrich Bertok, Jens Borken-Kleefeld, Janusz Cofala, Chris Heyes, Lena Höglund-Isaksson, Zbigniew Klimont, et al. 2011. “Cost-Effective Control of Air Quality and Greenhouse Gases in Europe: Modeling and Policy Applications.” Environmental Modelling and Software 26(12): 1489–1501. doi:10.1016/j.envsoft.2011.07.012.  Andreae, Meinrat O. 2019. “Emission of Trace Gases and Aerosols from Biomass Burning – an Updated Assessment.” Atmospheric Chemistry and Physics 19(13): 8523–46. doi:10.5194/acp-19-8523-2019.  Klimont, Zbigniew, Chris Heyes, Lena Hoglund-Isaksson, Florian Lindl, Younha Kim, Peter Rafaj, Pallav Purohit, et al. 2025. “Global Gridded Anthropogenic Emissions of Air Pollutants and Methane for the Period 1990-2050.” doi:10.5281/ZENODO.14748815.  Ouyang, Zutao, Robert B. Jackson, Marielle Saunois, Josep G. Canadell, Yuanhong Zhao, Catherine Morfopoulos, Paul B. Krummel, et al. 2025. “The Global Hydrogen Budget.” Nature 648(8094): 616–24. doi:10.1038/s41586-025-09806-1.  Paulot, Fabien, Gabrielle Pétron, Andrew M Crotwell, and Matteo B Bertagni. 2024. “Reanalysis of NOAA H2 Observations: Implications for the H2 Budget.” doi:10.5194/egusphere-2023-1602.