Final report on COOMET.QM-S1 (COOMET project no 483/RU/09): Supplementary comparison of primary standard gas mixtures: Nitrogen monoxide in nitrogen (50 µmol/mol)

Nitrogen monoxide is one of the main contaminants present in the atmospheric air due to emissions of vehicles and power stations. Taking into account the positive experience of VNIIM in the pilot study CCQM-P73 (Nitrogen monoxide gas standards, 30 ?mol/mol to 70 ?mol/mol), a COOMET project (No 483/RU/09) on the subject was decided and registered in the KCDB as supplementary comparison COOMET.QM-S1. This involved six National Metrology Institutes, aiming to consolidate or support their Calibration and Measurement Capabilities in this field. It was found that most of the results were consistent with the reference (gravimetric) values, with observed differences not exceeding ?1.3% and not exceeding either the appropriate assigned expanded uncertainties. There was, however, one exception: the INMETRO difference from the reference value is slightly higher than the expended uncertainty. The mixtures prepared for this exercise were found to be stable during about one year within the uncertainty of the measurements. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by COOMET, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).