Validation of multi-model decadal simulations of present-day central European air-quality

Abstract

Although air quality has improved in Europe, most of its population is still exposed to levels of pollutants that are harmful to health, such as nitrogen dioxide (NO${}_2$) or sulphur dioxide (SO${}_2$). Studying the processes that drive atmospheric chemistry is key to understanding their contribution to air quality. However, since many pollutants are secondary, since meteorology influences the chemical evolution of pollutants, disperses them and transport them and their precursors, among other factors, this task is extremely difficult. This makes thus the use of models essential for the study of air quality. In this work, we present the first long-term validation of air quality simulations in Central Europe for the 2010–2019 decade. The simulations were carried out using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and the Comprehensive Air Quality Model with Extensions (CAMx). Using the AirBase dataset, stations inside the model domain were classified into three categories according to their pollution burden, and the validation of the models was performed independently in each group. Our research shows that, generally, simulations underestimate pollutant concentrations – except ozone (O${}_3$) – most likely because of an incorrect monthly and hourly emissions profile and an overestimation of vertical mixing.