The sample air is led directly into the measuring cell via the aerosol inlet or other custom-designed air
inlets, e.g. for high wind speeds or overpressure. The particles in the sample air are being detected by
light scattering inside the measuring cell. The scattering light pulse of every single particle is being
counted and the intensity of its scattering light signal classified to a certain particle size. The measuring
principle is schematically shown in figure 1.