The atmosphere is abundant in aerosols, tiny particles floating in air, and we witness their existence constantly. This talk will present the latest studies on how aerosol particles form from trace gases by condensation, forming climatically relevant cloud condensation nuclei (CCN). It is of high importance to understand the details of aerosol formation and growth, since around half of CCN are of secondary origin. CCN sized particles can affect cloud properties such as their reflectivity or precipitation.

What limits our understanding of aerosol formation processes? The composition of neutral aerosol precursor molecules is difficult to measure, because they lack electric charge and their concentrations rarely exceed the detection limits of the current instrumentation (sub-pptV mixing ratios). This is one of the reasons why the first steps of particle formation processes are still partly unsolved after decades of research. This talk will give an overview of the development of highly selective methods for the detection of acidic and highly oxygenated aerosol precursor molecules and clusters, and will also discuss the findings during various field campaigns and laboratory experiment having utilized these instruments to solve the mysteries behind particle formation. Lastly, the future aims in particle formation studies will be presented.

Tuija Jokinen joined the CyI faculty in August 2021 from the University of Helsinki, Finland, where she also completed her Ph.D. in physics and M.Sc. in chemistry. After her dissertation, she joined University of California at Irvine, USA, for a postdoc year and she has also been a visiting researcher at TROPOS, Leipzig, Germany. Before joining CyI she was the Head of Unit for two ACTRIS calibration centers and a group leader for the Polar and Arctic atmospheric research group (PANDA).

She has a long history in working with chemical ionization - atmospheric pressure interface - time of flight mass spectrometers (CI-APi-TOF) and she specializes in field observations of aerosol precursor gases and sub 10 nm particle measurements. She aims at solving how aerosol particles are formed from condensing vapors in the atmosphere and how aerosols effect the climate and ecosystems around the Eastern Mediterranean and Middle East area.

Recently, she has been awarded a Starting Grant from the European Research Council (ERC) for an innovative project proposal exploring “The role of base molecules in Aerosol formation”