Global climate change impacted by greenhouse gases (GHG) has been the focus of the scientific community together with society and world authorities. GHG measurements applied in mitigation projects or in the construction of local emission factors must be reliable and accurate in quantification. Therefore, such actions yield more effective measurements with metrological approaches. In this regard, it is necessary to encourage the use of certified reference materials (CRMs) that ensure that the results are reliable, comparable and with well-established SI traceability. A suitable CRM can usually be developed with the characteristics of a real atmospheric sample. Considering the relevance of the subject and the innovation in the CRM development research of GHG, this study proposes to present the results of the development of a certified reference material of carbon dioxide in synthetic air at atmospheric level produced for the first time by the Brazilian Metrology Institute, Inmetro. The results of method validation for two analytical techniques to analyze carbon dioxide standards: gas chromatography with methanator catalyst (GC-FIDmeth) and cavity ring-down spectroscopy (CRDS) will also be presented and compared for a produced range of amount of substance from 380 to 580 micromol/mol. This study presents the steps of gravimetric development, analytical verification, stability study and finally the characterization of these CRMs of CO2 in atmospheric synthetic air matrices. The relative expanded analytical uncertainty for the CO2 standard was around 0.1 and 0.5% with a maximum deviation of 0.5% from the reference value for the CRDS technique; for GC-FIDmeth, an average uncertainty of 2% with a deviation ranging from 1.3 to 0.04%. The final certification uncertainty for CO2 in a synthetic atmospheric air matrix is on average of 0.24%. Inmetro has participated in a previous key-comparison of carbon dioxide at ambient levels, and its degree of equivalence was within 0.3% of the KCRV, but the uncertainty obtained by then (2008) was almost three times higher than the one obtained now by the new analytical method for the same type of mixture, ensuring the improving of the analysis of the laboratory with these new batch of CRM. The results presented and the dissemination of the use of these CRMs as quality tools ensure demonstrable metrological traceability on atmospheric research and GHG measurements which will have reliability in the process of compliance with GHG reduction goals, proposals in the mitigation measures of national contributions and in the inventory reports. Thus, this work aims to be a facilitator in the process of metrological control of GHG monitoring, in order to promote the benefits deriving from its use for sustainable development broadening the accuracy and precision of atmospheric measurements not only on national matters but within SIM.
Topic : Theme 1: Atmospheric Chemistry and Physics.
Reference : T1-A45
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