Volatile organic compounds (VOCs) are organic chemical compounds of 15 or less carbon atoms that have a high vapour pressure (> 10 hPa) at ambient temperature (20°C). VOCs are direct and indirect greenhouse gases and precursors of ozone and aerosols, which both contribute to the radiative forcing. Accordingly, long-term, accurate, worldwide measurements of VOCs are essential to understand climate change and to address its effects. Stable traceable references with a low uncertainty along with well-defined measuring methods are therefore indispensable for measuring reliably short and long-term amount-of-substance fractions of VOCs.

The EMPIR project 'Metrology for climate relevant volatiles organic compounds' (MetClimVOC) aims to improve the quality of reference gas standards for priority oxygenated VOCs, terpenes and halogenated VOCs, highly focusing on the dissemination of the standards to the field. Moreover, the measurement techniques will be validated within the framework of the project to ensure traceable measurements and to provide realistic and complete uncertainty budgets of the measurements.