12.10.23 Global experts and stakeholders meet to identify future isotope ratio metrology for sustained, internationally coordinated global greenhouse gas monitoring Project partner NPL chaired the working group for which traceability for amount fraction and isotope ratio of greenhouse gases is a high priority. Capabilities developed within the STELLAR project can be used to pilot key comparisons and improve international comparability. A pilot study on carbon dioxide isotope ratio is ongoing and future plans include methane isotope ratio. High precision isotope ratio measurements have been a key analytical tool in a variety fields, driving fundamental science and contributing to breakthroughs in many applications. Dual inlet isotope ratio mass spectrometry is still the most precise tool for measuring stable isotope ratios, but the introduction of novel spectroscopic techniques has revolutionised the measurement of key greenhouse gas components in air by enabling real-time in-situ field measurements. A recent focus of the metrology community has been on the development of accurate and traceable gas reference materials of carbon dioxide and methane with a range of isotope compositions. This research is aimed at meeting the calibration requirements of laboratories using commercial spectroscopic techniques for atmospheric source apportionment measurements. These help to discriminate anthropogenic emissions from natural contributions, providing important information about the processes involved in the sources, sinks and chemical transformations of these components. Christoph Nehrbass-Ahles with support from colleagues at the National Institute of Science and Technology (NIST) and the Technological Laboratory of Uruguay (LATU), organised and chaired a hybrid workshop on carbon dioxide and methane stable isotope ratio measurements. The two-day event at LATU brought together over 100 delegates from 26 different countries. The workshop outlined the role of metrology in this evolving area of science, what has been achieved and future research. Experts and key stakeholders from the global atmospheric monitoring community, the specialty gas industry and instrument manufacturers discussed the measurement challenges for atmospheric source apportionment of emissions, other environmental applications (e.g. palaeoclimatology and soil analysis) and requirements for energy gases. The outcomes will inform the terms of reference for a new CCQM task group aimed at providing a robust measurement infrastructure to underpin measurements of isotope ratio of carbon dioxide and methane. The event was timely as it followed an international WMO workshop on the development of a comprehensive integrated global observing system to support the implementation of the Global Greenhouse Gas Watch (GGGW). The new CCQM task group will be central to supporting the WMO and the broader greenhouse gas monitoring community develop a framework for sustained, internationally coordinated global greenhouse gas monitoring. The workshop was organised alongside the 48th meeting of the CCQM Gas Analysis Working Group chaired by Paul Brewer and a stakeholder workshop on Green Hydrogen. 28.07.23STELLAR Training at RUG Project partner RUG report on the training given to students under STELLAR. A bachelor’s student got trained in our lab from November 2021 to February 2022 to fill glass sample flasks with reference air from high pressure cylinders, condition our glass sample flasks to remove any traces of water and measure the isotope composition of atmospheric CO2 at our Aerodyne dual laser absorption spectrometer. A bachelor’s student got trained in our lab from April to July 2021 to prepare CO2-in-air samples from pure CO2 reference materials and measure the samples for their stable isotope composition on our Aerodyne dual laser absorption spectrometer. A bachelor’s student got trained in our lab from April to July 2022 to prepare pure CO2 samples from calcite reference materials using the phosphoric acid reaction. A bachelor’s student got trained in our lab from April to July 2023 to conduct an equilibration experiment of CO2 and water with the aim to develop pure CO2 reference material with an oxygen isotope composition linked to the VSMOW scale. Then on the 9th of May 2023 three members of the STELLAR project (Paul Brewer, Heiko Moossen and Nives Ogrinc) were in Groningen to be part of the promotion committee for the defense of my thesis with the title ‘Using laser absorption spectroscopy for the measurement of d 13C, d 18O and d 17O of atmospheric CO2. 07.07.23 Preventing drift of oxygen isotopes of CO2-in-air stored in glass sample flasks: new insights and recommendations STELLAR project partners RUG and the Max Planck Institute for Biogeochemistry have made a new project paper available, Preventing drift of oxygen isotopes of CO2-in-air stored in glass sample flasks: new insights and recommendations. It is known that the oxygen isotope composition of CO2-in-air, when stored over longer time periods in glass sample flasks, tends to drift to more negative values while the carbon isotope composition remains stable. The exact mechanisms behind this drift were still unclear. New experimental results reveal that water already inside the flasks during sampling plays a major role in the drift of the oxygen isotopes. A drying method to remove any water sticking to the inner walls by evacuating the flasks for more than 72 h while heating to 60°C significantly decreases drift of the oxygen isotopes. Moreover, flasks not dried with this method showed higher differences among drift rates of individual flasks. This is explained through the build-up of H2O molecules sticking to the inner walls. Humidity of the air samples in the flasks as well as surface characteristics will lead to differences among flasks. Results also show that permeability of water is higher through Viton O-ring flask seals than through polychlorotrifluoroethylene (PCTFE) shaft seals, and that the stability of flasks sealed with the latter is significantly better over time. You can find the paper here and over on our Documents page. 03-04.07.23 A Successful Final Project Meeting and Stakeholder Workshop for STELLAR A successful M36 final project meeting for the STELLAR project was held at Bushy House in Teddington, England by project partner NPL. Ruth Pearce and Garry Hensey (NPL) welcomed all to the meeting and Paul Brewer – NPL Fellow and Head of Science of the Atmospheric Environmental Science Department provided a short introduction. This was followed by presentations on work progressed under WP1 by Harro Meijer (RUG), a presentation on WP2 was provided by Stefan Persijn (VSL). Jelka Braden-Behrens (PTB) provided an overview of WP3 and the challenges and discussions with partners around the first phases, and upcoming challenges and discussions towards M36. Garry Hensey presented on the Impact Work progressed under WP4 and provided a guide to the project management status under WP5. During the work package presentations and discussions, there was further discussion with the consortium regarding the output of the project and future progress towards M36. For the Stakeholder Workshop, each technical WP Lead provided a ten-minute presentation of highlights from the project to some of the stakeholders. This was followed by a Q&A session. The project stakeholder committee are made up of members of the atmospheric monitoring community, specialty gas industry, gas analyser manufacturers, standardisation organisations and the metrology community. 28.04.23 Validation of Boreas: an instrument for simultaneous measurement of amount fraction and stable isotope ratios in methane Cameron Yeo of project partner NPL took part in a poster session at the EGU General Assembly 2023 that convened in Vienna, Austria & Online, 23–28 April 2023. Cameron presented her work on ‘Validation of Boreas: an instrument for simultaneous measurement of amount fraction and stable isotope ratios in methane’ as part of the STELLAR project. The poster garnered audience with a large blend of scientists from many disciplines and countries, including the opportunity to discuss the future of projects with current collaborators. A copy of the poster displayed at the event can be found here over on our Documents page. NPL chair 47th meeting of the CCQM-GAWG at the BIPM, Paris Paul Brewer chaired the 47th meeting of the Consultative Committee on Amount of Substance Gas Analysis Working Group (CCQM GAWG) at the BIPM in Paris. This is the first meeting to be held at the BIPM since 2019 and only the second in person (hybrid) meeting to be held since 2020. New proposals were presented by NPL for key comparisons on ethanol in air (CCQM-K93.2023; Panayot Petrov, NPL), carbon capture, utilisation and storage (CCUS; Manohara Gudiyor Veerabhadrappa, NPL) and for a new ongoing key comparison on NO2 (BIPM.QM-K6) coordinated by the BIPM that NPL has been helping to establish through a Joint Technical Project. Dave Worton presented updates on progress in two key comparisons, CCQM-K26b.2019 ambient SO2 in air and CCQM-K164 hydrogen purity that NPL is coordinating. The GAWG meeting was preceded by a joint Isotope Ratio Working Group (IRWG) and GAWG meeting which was co-chaired by Paul Brewer (NPL) where the final report of the first key comparison pilot of d13C and d18O of pure CO2 (CCQM-P204) including some of the challenges relating to scale realisation of VPDB and incomplete uncertainty budgets were discussed. Resolving these challenges is of critical importance for the success of ongoing key comparison BIPM.QM-K3 that will be used to underpin new and improved capabilities for value assignment of isotope ratio for CO2. A new joint task group entitled ‘Stable Isotope Ratio Metrology for Atmospheric Source Apportionment of Greenhouse Gases’ was proposed to strengthened collaborations between the IRWG and GAWGs. The aim of the task group is to facilitate the development of a robust measurement infrastructure for the accurate and real-time measurement of stable isotope ratios for atmospheric greenhouse gases. The focus will be on the stable isotopes of CO2 and CH4. Abneesh Srivastava (NIST) will act as the chair and Christoph Nehrbass-Ahles (NPL) was appointed Executive Secretary. The initial tasks include engaging with stakeholders such as the instrument manufacturers to develop best practice guidelines for the calibration of optical instruments and review the currently employed calibration hierarchies for d13C-CO2, d18O-CO2, d13C-CH4, and dD-CH4. At the joint IRWG/GAWG meeting Ruth Hill-Pearce (NPL) also presented an overview of the EMPIR project STELLAR. The STELLAR project is providing isotopic CO2 and CH4 reference materials, validation routines and traceability chains for spectroscopic techniques to allow measurements of the isotope ratio of CO2 and CH4 to be made in the field. This will allow improved discrimination between natural and manmade sources of GHGs to aid governmental agencies to better attribute emission sources, help demonstrate compliance to national reduction targets and enhance the effectiveness of future abatement strategies. 26.04.23 Metrology for Stable Isotope Ratio Measurements at the 2nd ISO-FOOD symposium Nives Ogrinc of project partner Jožef Stefan Institute took part in a poster session at the 2nd ISO-FOOD symposium. The poster entitled: Metrology for Stable Isotope Ratio Measurements was presented at 2nd ISO-FOOD symposium held 24.4.-26.4.2023 in Portorož in Slovenia 25.04.23 STELLAR at CCQM – Gas Analysis and Isotope Ratio WG Ruth Hill-Pearce presented an overview of the STELLAR project at the Meeting of the CCQM – Gas Analysis and Isotope Ratio Working Groups at the Bureau International des Poids et Mesures on the 25 April 2023. 21.04.23 Analysis of light stable isotopes in environmental and food samples: technical analysis and validation of methods Nives Ogrinc of project partner Jožef Stefan Institute arranged training entitled: Analysis of light stable isotopes in environmental and food samples: technical analysis and validation of methods. The session occurred April 19-21, 2023, at the Department of Environmental Sciences, Jožef Stefan Institute in Ljubljana. The training covered the techniques, methodology, evaluation of stable isotope results and measurements uncertainty in environmental and food samples. The project and its activities were also presented during the session. 12.12.22 Generation of CO2 gas mixtures by dynamic dilution for the development of gaseous certified reference materials STELLAR project partner INRiM have made a new project paper available, Generation of CO2 gas mixtures by dynamic dilution for the development of gaseous certified reference materials. The use of Certified Reference Materials (CRMs) is of utmost importance to achieve the comparability and traceability of data, which are essential features of measurement results in environmental and climate fields. The present paper focuses on the generation of gas mixtures at known composition of carbon dioxide at atmospheric amount-of-substance fraction in synthetic air by means of a dynamic dilution system, designed and implemented at the Istituto Nazionale di Ricerca Metrologica (INRiM). The validation of the dynamic system in terms of amount-of-substance fraction is presented. The system was also used to verify the carbon dioxide amount-of-substance fraction of a suite of gas mixtures gravimetrically prepared at INRiM in the framework of the EMPIR Joint Research Project 19ENV05 – STELLAR. Dynamic dilution proved to be an effective tool for the preparation and certification of CRMs for gaseous pollutants (i.e., carbon dioxide, nitrogen oxides) relevant for monitoring environmental pollution and climate changes. You can find the paper here and over on our Documents page. 01.11.22 STELLAR project at ECOFIRA Fernando Grau in the ECOFIRA and the Air Liquide stand Project partner, Air Liquide España, S.A., presented STELLAR within the framework of the ECOFIRA “Salón del Sector Químico para la Sostenibilidad y Economía Circular”, on October 4-6, 2022, in Valencia. The STELLAR project was indicated as a research case in Air Liquide’s presentation to the general audience. In addition, Air Liquide disseminated more information about the project at its stand, where a project poster was exhibited. A copy of the poster displayed at the event can be found here. 21.10.22 STELLAR at GGMT 2022 Farilde Steur of RUG and Heiko Moossen of MPG presented material on the project at the 21st WMO/IAEA Meeting on Carbon Dioxide, Other Greenhouse Gases and Related Measurement Techniques (GGMT-2022) Wageningen, The Netherlands from 16-21 September. Farilde presented on the Long term performance of a dual-laser absorption spectrometer for the measurement of δ13C, δ18O and Δ17O of CO2: results from measurements of stable isotope composition of atmospheric CO2 using an Aerodyne dual-laser absorption spectrometer over the period 2020- September 2022. Also, first results from primary reference materials measured on the spectrometer were shown. RUG are working on optimising the production and dilution of primary reference materials to realise a direct link to the VPDB(-CO2) scale for our optical measurements. Heiko provided a presentation on the Interlaboratory compatibility of δ13C-VPDB scale realisation. You can find links to the presentations above, and also over on our Documents page. 11.10.22 Successful M27 meeting for STELLAR A successful M27 meeting for the STELLAR project was held at the University of East Finland Kuopio campus and online by project partner VTT. Ruth Pearce and Garry Hensey (NPL) welcomed all to the meeting and noted that this was our first STELLAR in person meeting and that it was is a pleasure to see so many. This was followed by presentations on work progressed under WP1 by Harro Meijer (RUG), a presentation on WP2 was provided by Stefan Persijn (VSL). Javis Nwaboh (PTB) provided an overview of WP3 and the challenges and discussions with partners around the first phases, and upcoming challenges and discussions towards M36. Garry Hensey presented on the Impact Work progressed under WP4 and provided a guide to the project management status under WP5. During the work package presentations and discussions, there was further discussion with the consortium regarding the output of the project and future progress towards M36. Hilary Phillips and Mara Soares Silva from the EMPIR Management Support Unit (MSU), provided a talk on exploitation planning and generating impact from STELLAR developments. 01.10.22 Air Liquide present the STELLAR project to IRMS users (Left) The Air Liquide team: Fernando Grau, Arancha Oca and Antonio Carreira. (Right) The IRMS User Group Project partner Air Liquide España, S.A. participated in an event organised by Thermo Fisher Scientific and the University of Malaga, that gathered almost 50 users of IRMS (Isotope Ratio Mass Spectrometry) equipment belonging to one the most important scientific communities in Spain. The event took place at the University of Malaga in late September. Air Liquide presented the objectives of the STELLAR project, as well as its role within the project and its main commitment to contributing to the research. A copy of the poster displayed at the event can be found here. Isotope Ratio Mass Spectrometry is a specialisation of mass spectrometry, in which mass spectrometric methods are used to measure the relative abundance of isotopes in a given sample. Metrology is required to ensure advances in spectroscopy (i.e. IRMS, and Optical Isotopic Ratio Spectroscopy -OIRS) result in field deployable techniques that have reduced uncertainties in order to meet uncertainty requirements set by the World Meteorological Organisation. 09.09.22 Reference Materials: gas mixtures to support measurements for climate change studies. STELLAR project partner INRiM have made a new project paper available, Reference Materials: gas mixtures to support measurements for climate change studies. This work aims at presenting some activities carried out at INRiM for the development of new reference materials (RMs) of greenhouse gases to support measurements for climate change studies. Since the preindustrial era, greenhouse gases emissions due to human activities have dramatically increased, mostly due to economic and demographic growth and their concentrations in the atmosphere have grown continuously since 2011, reaching highest levels in 2019. The increase of greenhouse gases concentration in atmosphere due to anthropogenic emissions is the main cause of global warming and carbon dioxide (CO2) is one of the main culprits for this phenomenon. In this context, the capability of discriminating between anthropogenic and natural emissions is of utmost importance. The determination of the isotopic composition of CO2 can support the assessment of the uptake of CO2 in the environmental compartments, i.e. atmosphere and hydrosphere, and can help to distinguish natural from anthropogenic carbon in the atmosphere. The possibility to establish metrological traceability of the measurements of CO2 isotopic composition is a key aspect, and greatly relies on the availability of gaseous reference materials having compositions and uncertainties that are fit for purpose. In the past years, INRiM participated in the EMPIR project 16ENV06 SIRS “Metrology for stable isotope reference standards”, and is now taking part in the EMPIR project 19ENV05 STELLAR “Stable isotope metrology to enable climate action and regulation”. INRiM has experience in the preparation of gas standards by primary methods, namely gravimetry and dynamic dilution, which can be applied to the realisation of reference materials of CO2 at known isotopic composition. The present work describes the preliminary results obtained by INRiM in the preparation of pure CO2 RMs and at atmospheric amount fraction. Examples of uncertainty budgets and identification of the uncertainty sources are also given. You can find the paper here and over on our Documents page. 10.08.22New Thermo Scientific 253 plus 10 kV Isotope Ratio Mass Spectrometer at NPL Christoph Nehrbass-Ahles,Senior Research Scientist at NPL with the IRMS Project partner NPL have acquired a new Thermo Scientific 253 plus 10 kV Isotope Ratio Mass Spectrometer (IRMS). The IRMS will be able to measure δ13C-CO2 and δ18O-CO2 In pure CO2 samples. After a period of method development in 2023, NPL will look to expand their capabilities to measure atmospheric δ13C-CO2 and δ18O-CO2 as well as δ13CH4 and δ2H-CH4 in air. For the STELLAR project, the IRMS will be able to further work currently progressing under WP1 and WP2. The aim WP1 is to considerably improve gas reference materials of carbon dioxide that were developed as part of the EMPIR project 16ENV06 SIRS. These reference materials have target uncertainties of 0.1 ‰ for δ13C-CO2 and 0.5 ‰ for δ18O-CO2 measurements and must be strengthened to make them meet requirements for underpinning global monitoring. The aim of WP2 is to develop gas reference materials of pure methane and at 1.85 µmol mol-1 in an air matrix on a large scale and with a repeatability in the preparation process of 0.02 ‰ for δ13C-CH4 and of 1 ‰ for δ2H-CH4 and with target uncertainties of 0.2 ‰ for δ13C-CH4 and 5 ‰ for δ2H-CH4. The stability of the isotopic composition reference materials should be more than one year. The δ13C-CH4 and δ2H-CH4 isotope ratio reference materials will be traceable to the VPDB and VSMOW/SLAP scales, respectively. 10.07.22 Comparison of laser sources and driver electronics for optical isotope ratio spectroscopy Project partners VTT presented Comparison of laser sources and driver electronics for optical isotope ratio spectroscopy, a poster at the joint 10th International Symposium on Isotopomers (ISI) and 12th Isotopes Conference. The conference highlighted the latest developments and applications for the use of stable isotopes and brought together leading experts from a wide range of disciplines. 10.06.22 STELLAR Presented at Gas Analysis 2022 Eric Mussell Webber of project partner NPL recently presented at the Gas Analysis 2022 conference, held in Paris, France. The title was Stable Isotope reference materials of carbon dioxide, presenting progress from WP1 in STELLAR and the results of the SIRS project. The conference was attended by experts from across the gas analysis field, including those from industry, metrological institutes, and research laboratories. The aim of WP1 is to considerably improve gas reference materials of carbon dioxide that were developed as part of the EMPIR funded SIRS project (16ENV06). These reference materials have target uncertainties of 0.1 ‰ for δ13C-CO2 and 0.5 ‰ for δ18O-CO2 measurements and must be strengthened to make them meet requirements for underpinning global monitoring. 10.05.22 BIPM-WMO Workshop, Metrology for Climate Action, Registration and abstract submission open The BIPM-WMO Workshop on Metrology for Climate Action to be held as an online meeting on 26-30 September 2022. BIPM-WMO are very happy to announce that registration and abstract submission is now open at https://www.bipmwmo22.org/ The deadline for abstract submission is 31 May 2022 The workshop is open to experts and stakeholders active in the fields of climate science, observations, GHG mitigation and measurement, modelling and measurement science willing to contribute to the development of recommendations on key technical challenge areas for metrology in these fields. Abstracts for pre-recorded presentations and posters can now be submitted. Presentations and posters will be made available for online viewing before the workshop week and will be open for comment and questions by other participants. All with accepted submissions will be able to present and discuss these with other participants as posters in an interactive session on the Gather.Town Platform over 2 days of the Workshop. Those submitting abstracts should also independently register for the event. We look forward to contributions to the Workshop and inputs that will develop recommendations on key technical challenge areas for metrology in support of the physical science basis of climate change and climate observations and as an integral component of operational systems to estimate greenhouse gas emissions based on accurate measurements and analyses. Any queries on the workshop can be sent to firstname.lastname@example.org 25.02.22 Nordsol and Gasum supply biomethane samples for the Stellar project Global warming is one of the greatest current risks to humanity. Emissions of the major contributing greenhouse gases methane and carbon dioxide must be reduced to prevent even more severe climate changes. Both gases are currently at record high levels in the atmosphere, and this is mainly due to anthropogenic (human) activities. To determine the effectiveness of emission reduction policies it is essential to discriminate between anthropogenic sources and natural contributions. This can be done by measuring the stable isotopic composition of carbon dioxide and methane. The Stellar project will fill the existing traceability gap in the measurement of the isotopic composition of both gases by providing a new infrastructure for delivering gaseous carbon dioxide and methane reference materials and methods. Within the Stellar project, VSL is leading the development of isotopic methane reference materials. To make these reference materials, methane from fossil origin is mixed with methane from biogenic origin. Methane of fossil origin has been supplied by project partner Air Liquide. Methane from biogenic origin was recently supplied by Nordsol from a newly constructed bio-LNG installation in a partnership with Shell and Renewi. This bio-LNG installation is located in Amsterdam and was officially put into service by the Dutch king Willem-Alexander last October. In this installation, biogas is made from organic waste like out-of-date peanut butter, then purified to obtain biomethane and finally cooled down to obtain bio-LNG. Samples for VSL were taken after purification but before the cooling step. Filling of the cylinders with biomethane at the Nordsol bio-LNG installation by Jerom van Roosmalen, CEO of Nordsol. Another source of biogenic methane was supplied by the Finnish Gas company Gasum. Gasum is the main processer of biodegradable waste and supplier of biogas in the Nordic countries. They kindly supplied biomethane from their Lohja plant by filling 3 cylinders with gas for the Stellar project. The 3 cylinders filled by Gasum with biomethane from their Lohja plant. 15.02.22 Successful M18 meeting for STELLAR A successful M18 meeting for the STELLAR project was held online by project partner NPL. Ruth Pearce and Garry Hensey (NPL) welcomed all to the meeting held online due to the pandemic. This was followed by presentations on work progressed under WP3 by Javis Nwaboh (PTB) with presentations and contributions from Farilde Steur (RUG), Jan Conrad Petersen (DFM), Francesca Rolle (INRIM), Ville Ulvila (VTT), Joachim Mohn (Empa), Chris Rennick (NPL) and Christina Biasi (UEF). A presentation on WP2 was provided by Stefan Persijn (VSL). Garry Hensey presented on the Impact Work progressed under WP4 and provided a guide to the project management status under WP5. Heiko Moossen (MPG) presented on the progress made under WP1 with contributions from Christina Biasi (UEF) and Francesca Rolle (INRIM) During the work package presentations and discussions, there was further discussion with the consortium regarding the output of the project and future progress towards M27. You can find a copy of the meeting agenda here. 10.02.22JESIUM 2022, Kuopio, Finland 10–14 October 2022 Project partner UEF have organised the Joint European Stable Isotope Users group Meeting (JESIUM) to be held in Kuopio, Finland – and online, on the 10–14 October 2022. Stable isotopes have become a crucial research tool in a wide range of scientific fields. The purpose of the meeting is to bring together a broad range of stable isotope scientists from all over the world, to encourage communication across disciplines and country boundaries. The meeting aims to reflect on ideas and technologies through oral and poster presentations, informal discussions and debates, and during great social events. For more information, please visit the website: https://www.jesium2022-kuopio.org/ 09.02.22 Joint 10th ISI and 12th Isotopes Conference Project partner Empa have announced details for the joint 10th ISI and 12th Isotopes Conference, 29 May – 3 June 2022. The meeting will highlight the latest developments and applications for the use of stable isotopes and bring together leading experts from a wide range of disciplines. The topics and aims of the conference are to highlight the latest developments and applications for the use of stable isotopes and will bring together scientists from a wide range of disciplines to help foster knowledge exchange and collaboration. The target audience includes scientists, postdocs, PhDs and students from multiple research fields related to stable isotope sciences. Further information, is available here: 10th ISI and 12th Isotopes Conference, flyer 10th ISI and 12th Isotopes Conference, website 08.02.22 NPL illustrate project progress to the CCQM-IRWG Paul Brewer of project partner NPL recently provided a presentation to the CCQM-IRWG (CCQM Working Group on Isotope Ratios) on work progressed within the 16ENV06 SIRS and 19ENV05 STELLAR projects. Report from SIRS and STELLAR can be found here and also on our Documents page. The overall objective of the SIRS project was to fill a traceability gap by providing a new infrastructure for stable isotopes to deliver international gaseous CO2 reference materials to meet the increasing demand and international gaseous N2O reference materials with stated uncertainties to underpin measurements. The STELLAR project builds on this work. The CCQM (Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology) is responsible for developing, improving and documenting the equivalence of national standards (certified reference materials and reference methods) for chemical and biological measurements. It advises the International Committee for Weights and Measures (CIPM) on matters related to chemical and biological measurements including advice on the BIPM scientific programme activities. The BIPM is the international organization established by the Metre Convention, through which Member States act together on matters related to measurement science and measurement standards. It is also the home of the International System of Units (SI) and the international reference time scale (UTC). 26.01.22 Testing at NPL Aimee Hillier of project partner NPL and the testing of the CH4 to CO2 combustion system with ppm level CH4 and measuring the output on the CRDS (Cavity Ring-Down Spectroscopy). This forms part of an activity where NPL will develop a facility to convert the methane reference materials developed to carbon dioxide. In developing the facility, a full assessment of the sensitivities of the conversion process will be made in order to inform the uncertainty budget. Project partners RUG and MPG will also conduct a comparison of the pure carbon dioxide generated by combustion to the pure carbon dioxide reference materials from the 16ENV06 SIRS project using IRMS (Isotope Ratio Mass Spectrometry) and NPL will provide the reference materials. This work falls under WP2 of the project. The aim of WP2 is to develop first time gas reference materials of pure methane and at 1.85 µmol mol-1 in an air matrix on a large scale and with a repeatability in the preparation process of 0.02 ‰ for δ13C-CH4 and of 1 ‰ for δ2H-CH4 and with target uncertainties of 0.2 ‰ for δ13C-CH4 and 5 ‰ for δ2H-CH4. 01.08.21 Optical Isotope Ratio Spectroscopy – Complementing Isotope Ratio Mass Spectrometry Project partners from PTB, VSL, Empa, INRIM, RUG and DFM have collaborated together on the following paper, Optical Isotope Ratio Spectroscopy – Complementing Isotope Ratio Mass Spectrometry. Isotope ratio measurements and scale definitions are typically related to mass specectroscopy. This work discusses the challenges of optical isotope ratio spectroscopy and its prospects to significantly complement isotope ratio mass spectrometry. The paper was part of the OSA Optical Sensors and Sensing Congress 2021 and forms part of the session Isotopes and Metrology (EW5D) that occurred online and in Washington, DC United States 19–23 July 2021. You can find the paper here and over on our Documents page. 14.07.21 Boreas: A Sample Preparation-Coupled Laser Spectrometer System for Simultaneous High-Precision in Situ Analysis of δ13C and δ2H from Ambient Air Methane Project partner NPL have collaborated with the Department of Earth Sciences, Royal Holloway, University of London on the following paper for Analytical Chemistry (Anal. Chem. 2021, 93, 29, 10141–10151). Boreas: A Sample Preparation-Coupled Laser Spectrometer System for Simultaneous High-Precision in Situ Analysis of δ13C and δ2H from Ambient Air Methane . The paper presents a new instrument, “Boreas”, a cryogen-free methane (CH4) preconcentration system coupled to a dual-laser spectrometer for making simultaneous measurements of δ13C(CH4) and δ2H(CH4) in ambient air. Excluding isotope ratio scale uncertainty, we estimate a typical standard measurement uncertainty for an ambient air sample of 0.07‰ for δ13C(CH4) and 0.9‰ for δ2H(CH4), which are the lowest reported for a laser spectroscopy-based system and comparable to isotope ratio mass spectrometry. We trap CH4 (∼1.9 μmol mol–1) from ∼5 L of air onto the front end of a packed column, subsequently separating CH4 from interferences using a controlled temperature ramp with nitrogen (N2) as the carrier gas, before eluting CH4 at ∼550 μmol mol–1. This processed sample is then delivered to an infrared laser spectrometer for measuring the amount fractions of 12CH4, 13CH4, and 12CH3D isotopologues. We calibrate the instrument using a set of gravimetrically prepared amount fraction primary reference materials directly into the laser spectrometer that span a range of 500–626 μmol mol–1 (CH4 in N2) made from a single pure CH4 source that has been isotopically characterized for δ13C(CH4) by IRMS. Under the principle of identical treatment, a compressed ambient air sample is used as a working standard and measured between air samples, from which a final calibrated isotope ratio is calculated. Finally, we make automated measurements of both δ13C(CH4) and δ2H(CH4) in over 200 ambient air samples and demonstrate the application of Boreas for deployment to atmospheric monitoring sites. 26.05.21 Successful M9 meeting for STELLAR A successful M9 meeting for the STELLAR project was held online by project partner NPL. Dave Worton and Garry Hensey (NPL) welcomed all to the meeting held online due to the pandemic. This was followed by presentations on work progressed under WP1 by Harro Meijer (RUG), a presentation on WP2 was provided by Stefan Persijn (VSL). Jelka Braden-Behrens (PTB) provided an overview of the WP and the challenges and discussions with partners around the first nine months, and upcoming the challenges and discussions towards M18. Garry Hensey presented on the Impact Work progressed under WP4 and provided a guide to the project management status under WP5. During the work package presentations and discussions, there was further discussion with the consortium regarding the output of the project and future progress towards M18. 16.04.21 A New Collaborator for STELLAR The STELLAR project consortium would like to welcome on board Dr. Ian Chubchenko, Senior Research Scientist of the Physical and Chemical Metrology Department within the D.I. Mendeleev All-Russian Institute for Metrology (VNIIM). VNIIM is the successor of the Main Chamber of Measures and Weights which was the first in Russia and one of the oldest in the world among metrological institutions. Today, VNIIM is one of the largest world centers of scientific and practical metrology. It is the leading Russian organization in the field of precise measurements in metrology and the major centre of national measurement standards in Russia. VNIIM works under the auspices of the Federal Agency of Technical Regulation and Metrology. 02.03.21 Successful Stakeholder Catch-Up Meeting for STELLAR A successful stakeholder catch-up meeting for the STELLAR project was held last week. Project Co-Ordinator Ruth Pearce (NPL) took the stakeholders through an introduction to the project, and this was followed by presentations on WP1 (Next generation carbon dioxide isotope ratio gas reference materials) by Harro Meijer, RUG; WP2 (First time isotope ratio gas reference materials for δ13CH4 and δ2H-CH4) by Stefan Persijn, VSL; WP3 (Advancing optical isotope ratio spectroscopy for carbon dioxide and methane) by Jelka Braden-Behrens, PTB and WP4 (Creating Impact) by Garry Hensey, NPL. After the work package presentations and discussions, there was further discussion with the stakeholders regarding the output of the project and future opportunities. The stakeholders attending was from a diverse range of sectors (metrology, academia and industry) with notable contributions to the discussion from members of institutes BIPM, NOAA Global Monitoring Division, Licor and INSTAAR, University of Colorado. You can watch detail from the meeting above. The presentations from the meeting are available from our Documents & Publications page. 17.09.20 A successful Kick Off meeting for STELLAR A successful Kick Off meeting for the STELLAR Project was held by NPL on the 17 September. Due to the current pandemic situation, the meeting was held online with all project partners in attendance.