<p>CiGas provides support to the NFs and users for achieving traceability of measurements, quality assurance and quality control of the measurements and the data before submission to public databases. Therefore, data quality and compatibility of ACTRIS trace gas measurements as defined in the MG are ensured by station performance tests as parallel offline measurements, side-by-side intercomparisons, on-site reference measurements, round robins, and by reviewing the data. CiGas provides working standards and target gas to NFs and users, links the measurement of ACTRIS reactive trace gases to primary standards and ensures the state-of-the-art traceability international scales.</p>