CIPM MRA COMPARISON REPORTS

PILOT STUDY

CCQM-P239

CO2 isotope ratios in CO2 in air mixtures

J. Viallon , E. Flores , T. Choteau , R. Wielgosz , A. Hillier , C. Nehrbass-Ahles , K. Hong , H.J. Eun , J.H. Kang , S. Lee ... , F. Rolle , S. Pavarelli , F. Durbiano , F. Pennecchi , F. Camin , X. Xu , B. Krajnc , P. Vreča , N. Ogrinc , K. Harris , A. Srivastava , N. Jawis , A. Simsek , I. Chubchenko , A.V. Kolobova , H. Moossen , L. Huang , P. Steur , S. Michel

Citation J. Viallon et al 2026 CIPM MRA Comparison reports 08022

https://doi.org/10.59161/LBWR2688

Authors

Joële Viallon

https://orcid.org/0000-0001-8934-9484 Bureau International des Poids et Mesures (BIPM) BIPM - International Organization

Edgar Flores

https://orcid.org/0000-0003-1910-7265 Bureau International des Poids et Mesures (BIPM) BIPM - International Organization

Tiphaine Choteau Bureau International des Poids et Mesures (BIPM) BIPM - International Organization

Robert Wielgosz

https://orcid.org/0009-0001-3803-0825 Bureau International des Poids et Mesures (BIPM) BIPM - International Organization

Aimee Hillier

https://orcid.org/0000-0003-0436-9246 National Physical Laboratory (NPL) United Kingdom

Christoph Nehrbass-Ahles

https://orcid.org/0000-0002-4009-4633 National Physical Laboratory (NPL) United Kingdom

Kiryong Hong Korea Research Institute of Standards and Science (KRISS) Korea, Republic of

Han Jun Eun Korea Research Institute of Standards and Science (KRISS) Korea, Republic of

J. H. Kang Korea Research Institute of Standards and Science (KRISS) Korea, Republic of

Sangil Lee Korea Research Institute of Standards and Science (KRISS) Korea, Republic of

Francesca Rolle

https://orcid.org/0000-0002-0315-3315 Istituto Nazionale di Ricerca Metrologica (INRIM) Italy

Stefano Pavarelli

https://orcid.org/0009-0005-9574-1657 Istituto Nazionale di Ricerca Metrologica (INRIM) Italy

Francesca Durbiano

https://orcid.org/0000-0002-4781-519X Istituto Nazionale di Ricerca Metrologica (INRIM) Italy

Francesca Pennecchi

https://orcid.org/0000-0003-1328-3858 Istituto Nazionale di Ricerca Metrologica (INRIM) Italy

Federica Camin

https://orcid.org/0000-0003-0509-6745 International Atomic Energy Agency (IAEA) IAEA - International Organization

X. Xu International Atomic Energy Agency (IAEA) IAEA - International Organization

Bor Krajnc

https://orcid.org/0009-0008-4264-9664 MIRS/Jozef Stefan Institute/Low and Medium Energy Physics F2, Environmental Sciences O2 (MIRS/IJS/F-2,O-2) Slovenia

Polona Vreča

https://orcid.org/0000-0002-3972-4001 MIRS/Jozef Stefan Institute/Low and Medium Energy Physics F2, Environmental Sciences O2 (MIRS/IJS/F-2,O-2) Slovenia

Nives Ogrinc

https://orcid.org/0000-0002-5709-1594 MIRS/Jozef Stefan Institute/Low and Medium Energy Physics F2, Environmental Sciences O2 (MIRS/IJS/F-2,O-2) Slovenia

Kimberly Harris

https://orcid.org/0009-0004-4082-8483 National Institute of Standards and Technology (NIST) United States

Abneesh Srivastava

https://orcid.org/0000-0002-8527-112X National Institute of Standards and Technology (NIST) United States

Nwaboh Jawis

https://orcid.org/0000-0001-5251-5215 Physikalisch-Technische Bundesanstalt (PTB) Germany

Adnan Simsek

https://orcid.org/0000-0003-1783-8646 TÜBITAK Ulusal Metroloji Enstitüsü (UME) Tükiye

Ian Chubchenko

https://orcid.org/0000-0002-3408-5116 D.I. Mendeleyev Institute for Metrology, Rosstandart (VNIIM) Russian Federation

Anna V. Kolobova

https://orcid.org/0000-0001-9030-446X D.I. Mendeleyev Institute for Metrology, Rosstandart (VNIIM) Russian Federation

Heiko Moossen

https://orcid.org/0000-0003-4768-2603 Max Planck Institute for Biogeochemistry (MPI-BGC) Germany

Lin Huang

https://orcid.org/0000-0002-8200-4632 Environment and Climate Change Canada (ECCC) Canada

Pharilda Steur

https://orcid.org/0000-0002-2958-392X University of Groningen (RUG) Netherlands

Sylvia Michel

https://orcid.org/0000-0002-5651-1163 Institute of Arctic and Alpine Research (INSTAAR) United States

Abstract

The pilot study CCQM-P239 aimed at evaluating the level of compatibility of laboratories' measurement capabilities to value assign isotope ratios (expressed as isotope delta) of CO₂ (δ ¹³C vs. VPDB and δ ¹⁸O vs. VPDB-CO₂) in carbon dioxide in air gas mixtures. Such capabilities have been in development at: National Metrology Institutes (NMIs) and expert laboratories that have been developing CO₂ (isotope ratio) in air cylinder standards for calibrating optical spectroscopic techniques; the atmospheric community laboratories measuring isotope ratios of CO₂ in air, traditionally by mass spectrometry techniques (linked to the standards of the WMO-GAW Central Calibration Laboratory or other systems); and NMIs and expert laboratories developing CO₂ in air amount fraction standards that need CO₂ isotope ratios values for accurate amount fraction measurements.

The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

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