Bilateral comparison of primary reference materials (PRMs) containing methanol, ethanol and acetone in nitrogen

Abstract A range of oxygenated volatile organic compounds (OVOCs) are present in the atmosphere as a result direct emissions and products atmospheric oxidation. Long-term measurements important to understand changes these emission sources oxidation processes. Accurate stable traceable gaseous primary reference materials needed underpin rigorous quality assurance control at monitoring stations such those organised by World Meteorological Organization Global Atmosphere Watch (WMO-GAW) programme. The development capability for providing (PRMs) OVOCs is paramount importance due increasing prevalence urban also because there currently no Central Calibration Laboratory (CCL) components within WMO-GAW This EURAMET bilateral comparison demonstrates measurement compatibility (? 3%) three (methanol, ethanol acetone) nominally 5 µmol mol ?1 between two National Metrology Institutes: Physical (NPL), UK Van Swinden Laboratorium (VSL), Netherlands. shows that gravimetric method value assignment applicable acetone but more complicated procedure must be employed assign methanol corrections adsorption effects, which can large 10 % nominal value. work making appropriate ensure accuracy materials. NPL VSL used different approaches make confidence independent verification. supports new calibration capabilities methanol, 1 ?mol –10 with expanded uncertainties 6.9 (3 %), 7.3 %) 1.7 (2 respectively, realized key database required traceability infrastructure long-term global OVOCs.