Laser Granulometry At the Core of Aerosol Performance

Particle size is an essential parameter for characterizing the behaviour and performance of spray aerosol products. Whether it is an inhaled medicine, a cosmetic spray, a disinfectant or a pesticide, the particle size distribution of the droplets directly determines the product’s efficiency, safety and quality of application.

Particle size analysis of an aerosol spray by laser diffraction.

At LEREM, this distribution is measured using a Malvern Spraytec SP 2000 laser granulometer, a reference instrument for real-time analysis of liquid particles suspended in air.

Based on the principle of light diffraction, this instrument makes it possible to accurately determine droplet sizes according to the Fraunhofer model, in compliance with ISO 13320:2020.

During the test, a helium-neon laser beam (633 nm) passes through the generated spray. The intensity and diffraction angle of the laser are then analysed to determine the spray’s particle size distribution.

The respirable fraction is particularly important for toxicological and inhalation studies.

This analysis helps optimise the formulation, the choice of propellant, the design of the valve and actuator, and the quality control of production batches.

Our team’s expertise ensures reliable and independent interpretation of the data, particularly in complex cases involving liquefied propellants, where specific corrections must be applied to compensate for so-called “beam steering” effects.