Does the onset of new particle formation occur in the planetary boundary layer?

The planetary boundary layer (PBL) is chemically and physically the most active and complex part of the atmosphere as it has high loading of both aerosols and gaseous precursors. To detect directly the first steps of new particle formation in the atmosphere, we are measuring chemical and physical processes within the PBL (altitudes up to 1 km). Our study consists of both airborne Zeppelin measurements and ground based in-situ measurements. Using Zeppelin, we measured vertical profiles of aerosol particles and chemical compounds during the growth of the PBL from sunrise until noon. These measurements are part of the PEGASOS project. It aims to quantify the magnitude of regional to global feedbacks between the atmospheric chemistry and physics, and quantify the changing climate. The Zeppelin flights are observing radicals, tarce gases, and aerosols inside the atmospheric layers up to 1 km height over Europe. The main nucleation campaigns are performed in Po Valley, Northern Italy (summer 2012), and Hyytiala, Southern Finland (spring 2013). The results will support the numerical air-quality and climate modelling.