A powerful laser (details to be inserted here) and modulator are used to generate a sheet of laser light that crosses the aerosol plume.
A high resolution camera is used to record video of the aerosol plume as it is illuminated by the laser light, filming at 90 deg/perpendicular to the sheet of laser light
Individual aerosol particles can then be tracked as they move through the laser sheet
Statistical analysis determines relative concentrations of particles throughout the light sheet.
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