Metrological Traceability for Volatile Organic Compounds (VOCs)
The European project MetClimVOC (Metrological Traceability for Volatile Organic Compounds “VOCs“), funded under the EMPIR – European Metrology Programme for Innovation and Research, aimed to develop new metrological references for the measurement of volatile organic compounds (VOCs) of environmental relevance, including oxygenated species, terpenes, and halogenated VOCs.
Although present in the atmosphere at very low concentrations, these compounds play a significant role in tropospheric ozone formation, climate change, and air quality.
A Project to Ensure SI Traceability
Before the start of the project, no SI-traceable reference gases were available for several VOCs at low concentrations, limiting the ability of European monitoring networks to compare data with full metrological reliability.
The MetClimVOC consortium, coordinated by METAS (Switzerland) and involving national metrology institutes and industrial partners from across Europe, developed new primary SI-traceable gas mixtures and calibration protocols in accordance with ISO 6145-10.
Fine Metrology’s Contribution
Fine Metrology contributed its industrial expertise to the project by supporting the production and characterization of permeation tubes used for generating reference mixtures of selected halogenated VOCs (including HFC-32, HFC-365mfc, CH₂Cl₂, CCl₄, HFO-1336mzzZ, and 1,2-dichloroethene).
Using its proprietary WaferCAL® and ELCAL® product lines, the company developed and supplied permeation tubes with high thermal stability, constant emission rates, and high compound purity, verified through long-term stability and reproducibility tests conducted in collaboration with METAS.
These devices enabled the generation of reference flows at low molar fractions (< 10 nmol/mol) with uncertainties below 3% and stability up to 18 months, ensuring SI traceability and comparability of the produced reference gases across Europe.
Impact and Results
Thanks to Fine Metrology’s contribution, the project was able to rely on stable and reproducible emission sources for the validation of calibration protocols.
The knowledge gained on polymeric membrane materials, permeation parameter optimization, and temperature control allowed the company to further improve its production processes and integrate the metrological requirements identified by the consortium into its next-generation products.
The MetClimVOC project represents an important step toward more accurate and harmonized atmospheric monitoring at the European level, supporting the implementation of EU Directive 2024/2881 on air quality and contributing to the reduction of environmental and climate impacts associated with VOCs.
