The workgroup 'Tropospheric Aerosols' investigates physical and optical particle properties under laboratory and field conditions. Our goal is to improve the understanding of tropospheric aerosol processes, spatial and temporal aerosol trends, and the assessment of human particle exposure (ultrafine particles and soot) in urban areas. We are a center of competence for the technical development of physical and optical particle instrumentation, and their quality assurance.

The working group 'Experimental Cloud Physics' examines the interactions between aerosol particles and clouds. The main focus of the research is on the formation and freezing of cloud droplets. Furthermore, investigations are carried out on the interactions between turbulence in clouds and its effects on cloud droplets. These investigations are conducted in the laboratory as well as during ground-based and airborne field experiments, and are accompanied by instrument developments and model simulations.

The tasks of the WCCAP and the associated working group include audits of aerosol measurement programs of national and international observatories, calibration workshops for in situ aerosol measurement instruments, training of young scientists through training courses, consulting on the implementation of aerosol measurement programs, partnerships with international GAW observatories and the development of guidelines and recommendations for microphysical and optical in situ aerosol measurements.