Unpredictable weather, extreme rainfall or snow increasingly leads to challenges for people and nature. Paradoxically, less air pollution and cleaner clouds could lead to more extreme events. To understand how clouds will respond to changes in pollution, and in a post-fossil world is key for the world’s ability to plan for the future. This is at the heart of the EU-funded research project CleanCloud (Clouds and climate transitioning to post-fossil aerosol regime), comprised of 20 European research institutes with expertise in land- and space-based remote sensing, laboratory and in-situ atmospheric aerosol and cloud chamber experiments, and kilometer and large-scale aerosol, cloud, and climate modelling. CleanCloud, aims to quantify and understand regional and temporal effects of ACI-related processes, and how they will evolve in the transition to the post-fossil regime.

CleanCloud PIANO is a documentary film about the 2025 CleanCloud PIANO (chamber camPaign for studyIng the cloud-relevAnt properties of Natural aerosOl) Environmental Chamber experiments to study the ability of seasalt and dust particles (fresh and aged) to serve as nuclei that make cloud droplets and ice crystals in clouds. The experiments take place at the Center for Chemistry of Clouds at Aarhus University (at Aarhus, Denmark) and the Center for the Study of Air quality and Climate Change at the Institute for Chemical Engineering Sciences at the Foundation Research and Technology, Hellas (in Patras, Greece). This movie shines a light on:

• The Patras Team: Meet more of the dedicated researchers whose diligence and drive brought the PIANO experiments to life at the Foundation for Research and Technology - Hellas (FORTH) in Greece.
• Goals becoming evermore ambitious: What began as a focused chamber experiment on dust ageing is now expanding into something  beyond clouds - and includes public health, ecosystems.
• Trials and Tribulations: Behind every successful measurement lies a history of failed attempts and repeats. This episode reveals the “open secret” of science: progress is built on learning from past failures, and discovery grows from persistence.

Don't forget to check out the other videos related to PIANO and CleanCloud on this channel!

Campaign PIs: Merete Bilde (Aarhus University), Marianne Glasius (Aarhus University), Spyros Pandis (FORTH), Athanasios Nenes (FORTH/EPFL).

Interviews, video editing & montage: Nikitas Diamantopoulos

Acknowledgments: Funding was provided by the European Union’s Horizon Europe project “CleanCloud” (Grant agreement No. 101137639) and the Swiss National Science Foundation (SNSF) projects "LipicAir" and “AAIDI”, and SNSF R'Equip funding. Finally, we acknowledge support from the ETH Domain Joint Initiative ReCLEAN.

For more information, please visit the CleanCloud project website (https://projects.au.dk/cleancloud/cleancloud-project) or contact the CleanCloud coordinators (Ulas Im; ulas@envs.au.dk; Athanasios Nenes; athanasios.nenes@epfl.ch).