SHERPA-Cloud: An open-source online model to simulate air quality management policies in Europe

In this manuscript we present the SHERPA-Cloud online simplified air quality model, which is an evolution of the previous offline SHERPA model. SHERPA-cloud is a meta-model of a full Chemical Transport Model, and can be used to screen how policies would impact air quality. The main advantage of SHERPA-cloud (in comparison to the previous model version) are its speed (5 time faster than the offline version), its accessibility (permanent online availability) and its easier and more cost-effective maintenance (automatic updates can be shared more easily, and tool developments are facilitated). From the IT infrastructure and technologies points of view, the SHERPA-Cloud is based on an in-house cloud system called BDAP (Big Data Analytic Platform) which provides a ’JupyterLab’ service and tools to create dashboards using ’Voilà’ technology. SHERPA-Cloud is a useful easy-to-use tool in the hands of policy makers, citizens, NGOs and industries, that allows for interactive and participative policy developments. Indeed, it allows to quickly identify and quantify changes in air quality resulting from implementing emission reduction strategies, in terms of either geographical or sectoral policies.