A major milestone reached on the way to AIDAc2

The AIDA facility was built during the years 1995 to 1997. The former reactor building 322 at KIT Campus North was modified to host the new aerosol chamber (see our history series). On 16 July 1996, the large aluminum vessel with a diameter of 4 m and a height of 7.5 m was moved into the modified building. During the following year, AIDA was equipped with technical systems and a comprehensive set of instrumentation for trace gas, aerosol and cloud measurements (see our virtual tour for more details). The new facility came into operation on 22 May 1997, with a research program focusing on heterogeneous chemistry and polar stratospheric clouds during the first years of operation. A few years later, the AIDA team further extended the instrumentation and by that also experimental capability. Thanks to this development, the AIDA facility was operated until 2025 as a worldwide unique aerosol and cloud simulation chamber. Many campaigns were planned, organized and conducted in close collaboration with national and international partners. A broad range of research topics were covered including aerosol formation, chemistry and optical properties, as well as the important role of atmospheric aerosols to induce the formation of the ice phase in clouds and by that also markedly influence the formation of precipitation and the radiative properties of clouds in the climate system.

In 2019, we decided to replace the existing “classic” AIDAc facility with a new and improved atmospheric simulation chamber we call AIDAc2, where “c2” stands for “cold and clean”. Major new features will be an temperature range to -100 °C, a full metal-sealed, vacuum-tight stainless steel chamber for experiments at low pressures and under ultra-clean conditions, an extended LED-based sunlight simulator, an extended set of up-to-date and more sensitive in situ and sampling instruments for trace gases, aerosols, cloud droplets and ice crystals, and a cold room underneath the main chamber for vertical sampling of large particles to instruments operated at sub-zero temperatures, e.g. for measuring and characterizing ice crystals or thermo-labile aerosol particles. The AIDAc2 project started on 1 August 2021 with funding from the Federal Ministry of Research, Technology and Space in the framework of the ACTRIS-D project.

A major milestone of the AIDAc2 project was reached on 29 September 2025 with the removal of the AIDAc vessel from the building. During October 2025, the vessel was finally segmented for proper disposal, and all other components from the AIDAc facility were demolished and removed from the laboratory to make room for the new Atmospheric Simulation Chamber AIDAc2. The laboratory will then be refurbished and prepared for the installation of AIDAc2, which will start in March 2026, according to the current project plan. Our main contacting partner for the engineering and constructing AIDAc2 is the Bilfinger Nuclear and Energy Transition GmbH in Würzburg, Germany. The new AIDAc2 vessel is currently constructed by the Cadinox company in Spain and is expected to arrive at KIT during the first week of April 2026. The cooling system is engineered and constructed by ILK Dresden.