How the understanding of atmospheric new particle formation has evolved along with the development of measurement and analysis methods

The chain of chemical and physical processes leading to formation of new aerosol particles from gaseous precursors vapors is often called new particle formation (NPF). Although first observations of atmospheric NPF date back to more than a century ago, many aspects of the phenomenon and its importance on global climate remained unknown for a long time. Along with the development of more robust measurement techniques enabling continuous field measurements of particle size distributions down to the size of recently formed particles and their precursors vapors, NPF research has taken leaps forward in the past decades. In this article we review how the new measurement methods has enabled us to observe, analyze and classify atmospheric new particle formation events and how this has changed our understanding of the process and its significance in the atmosphere.