LOAC (Light Optical Particle Counter): a new aerosols counter for the determination of their sizes and their main nature under meteorological balloons

LOAC is light particle counter/sizer of 400 grams. Including the gondola and the battery, the total weight is around 1 kg. The measurements are conducted at two scattering angles: the first one, at 10°, is insensitive on the nature of the aerosols, and is used to determine the particle concentrations in 20 size classes within a diameter range of 0.4-100 mm. The second angle is at 60°, where the scattered light is strongly dependent on the nature of the aerosols. The ratio of the measurements at the two angles is used to discriminate between different types of particles dominating the nature of the aerosol. Several flights under meteorological balloons have been already conducted successfully.

The instrument was developed in a frame of a collaboration between French national research laboratories, the Environnement-SA company and the MeteoMODEM company.