Adriaan van der Veen studied Chemistry in Utrecht, the Netherlands, and obtained in his PhD in physical chemistry in 1997 at the same university. He has been working since 1994 at VSL, the Dutch National Metrology Institute, first as scientist, currently as chief scientist in Chemistry and Data Science & Modelling. He is an expert in gas analysis, interlaboratory comparisons, reference materials, measurement uncertainty and standardisation. He has organised numerous key comparisons in the gas analysis area. He has contributed to several standards related to certificates, including ISO 6141 for calibration gas mixtures and ISO Guide 31 for reference materials. He is the chairman of ISO/TC193 Natural gas and was chairman of ISO/TC158 Analysis of gases until 2022.