Aerosols mesurements with Light Optical Aerosols Counter (LOAC) at "Ballon de Paris Generali"

The LOAC aerosol counter measures fine particle concentrations since 2013, across 19 size ranges between 0.2 and about 30 µm. It operates from a small enclosure mounted on the side of the Generali tourist balloon in Paris (Parc André Citroën), as part of a scientific collaboration agreement between CNRS and Aerophile SAS. Measurements are taken at ground level, as well as during balloon flights up to 150 m in altitude, and up to 300 m in some cases.

This instrument is based on the principle of optical detection of particles passing through a laser beam, using diffraction to establish a direct relationship between the intensity of scattered light and particle size. LOAC performs measurements under all weather conditions. These measurements make it possible to characterize different pollution episodes in Paris, as they are conducted in an “urban background” environment, meaning without strong nearby emission sources. They also allow the study of vertical particles transportation.

The concentration of particles smaller than 1 µm remains on average constant with altitude, whereas concentrations of particles of at least a few micrometers decrease due to sedimentation. The measurements also reveal an annual cycle in fine particles, with higher average values in winter than in summer for the smallest particles (likely linked to heating) while larger particles show the opposite cycle, associated with higher pollen concentrations in spring and summer.

This dataset is part of the Dat@OSUC collection in the Recherche Data Gouv data repository

OSUC is a federative structure that brings together three research laboratories: the Earth Sciences Institute of Orléans (ISTO), the Laboratory of Physics and Chemistry of the Environment and Space (LPC2E) and the Radioastronomy Observatory in Nançay (ORN).