Bert Verreyken obtained his PhD in atmospheric physics and analytical chemistry in 2021. He is currently affiliated with the Royal Belgian Institute of Space Aeronomy (Brussels, BE) and the University of Liege – Gembloux Agro-Biotech (Gembloux, BE) where he aims to combine in situ measurements and modelling to study bi-directional exchange and of reactive trace gasses between ecosystems and the atmosphere. Before arriving in Belgium, Bert was an NRC fellow at Chemical Sciences Laboratory of the National Oceanic and Atmospheric Administration (Boulder, CO, USA). During his time in the USA, he focused on quantifying emerging anthropogenic emissions of volatile chemical products (e.g., personal care products, paints, and adhesives) using a mesoscale chemistry and an atmospheric transport model. His expertise lies primarily in the use of the proton-transfer-reaction mass-spectrometry technique to measure reactive trace gasses, as well as the development and application of atmospheric transport models to analyze in-situ measurements.