Atmospheric simulation chambers are the most advanced tools for elucidating processes that occur in the atmosphere. They lay the foundations for air quality and climate models and also aid interpretation of field measurements. EUROCHAMP-2020 will further integrate the most advanced European atmospheric simulation chambers into a world-class infrastructure for research and innovation. A co-ordinated set of networking activities will deliver improved chamber operability across the infrastructure, as well as standard protocols for data generation and analysis. Outreach and training activities will foster a strong culture of cooperation with all stakeholders and users. Collaborative links will be established with other environmental research infrastructures to promote integration and sustainability within the European Research Area. Cooperation with private sector companies will be actively promoted to exploit the innovation potential of the infrastructure by supporting development of scientific instruments, sensor technologies and de-polluting materials. Trans-national access will be extended to sixteen different chambers and four calibration centres. A new, upgraded data centre will provide virtual access to a huge database of experimental chamber data and advanced analytical resources. Joint research activities will enhance the capability of the infrastructure to provide improved services for users. Measurement techniques and experimental protocols will be further developed to facilitate new investigations on climate change drivers, impacts of air quality on health and cultural heritage, while also stimulating trans-disciplinary research. Advanced process models will be developed for interpretation of chamber experiments and wider use in atmospheric modelling. Overall, EUROCHAMP-2020 will significantly enhance the capacity for exploring atmospheric processes and ensure that Europe retains its place as the world-leader in atmospheric simulation chamber research.