DestinE-AQ: High-resolution air quality forecast, analysis, and scenario simulations coupled to the Digital Twin of DestinE

<p>Extreme air pollution events of high concentrated surface ozone (O₃) or particulate matter (PM) pose a lethal threat to humans worldwide. To investigate air quality under extreme atmospheric situations, the DestinE-AQ use case develops a comprehensive user interface that enables high resolution air quality forecasts and analysis by combining numerical simulations, machine learning approaches and observations. The core of the system encloses access to the open database of global air quality observations (i.e. the Tropospheric Ozone Assessment Report data base, TOAR), innovative machine learning workflows (e.g. MLAir, IntelliO3-ts) including downscaling modules, and high resolution numerical simulations using the state of the art chemistry transport model EURAD-IM (EURopean Air pollution Dispersion- Inverse Model). The aspired air quality forecasts and analyses will dynamically be driven by the DestinE Digital Twin for weather extremes. Thus, the pursued horizontal resolution of the air quality simulations is identical to the resolution of the DestinE digital twin (< 1 km²).</p> <p>To provide reliable air quality analyses, the system makes use of observational data in both the machine learning tools and EURAD-IM by enabling 3D-var data assimilation. While focusing on Europe, the system will demonstrate how observations and physics-based and data-driven models can be woven together to achieve enhanced realism and finer resolution of air pollution information and thus provide better support to decision makers. The system is complemented by an efficient ensemble module that enables emission scenario simulations to test and develop air pollution mitigation strategies for future extreme events under realistic conditions. The development of the user interface is done in close cooperation with the German and North Rhine-Westphalian Environment Agencies to meet the end users&#8217; needs. The system will provide detailed information about air quality, its underlying chemical processes, the influence of meteorological extreme events, and the impacts of anthropogenic emissions on air quality. Hence, it will also serve the scientific community to answer questions on air quality and atmospheric chemical processes under extreme weather conditions that are expected to increase in future. To allow for the investigation of the human impact of extreme events, the DestinE-AQ focuses on the key air pollutants PM_2.5, nitrogen oxides (NO_x), and O₃ in the planetary boundary layer. The potential combination of the system with socio-economic and medical models will be evaluated.</p>