Analysis and control of aerosol flow

An aerosol generation system, comprising:

• a flow device (1) for generating an aerosol flow;
• a light source arrangement (6) and a light detector (3) for detecting light which has interacted with the aerosol flow;
• a controller (9) for controlling the light source arrangement and for interpreting the detected light signals;
• wherein the controller is adapted to:
• control the light source arrangement to provide a first signal at a first wavelength and to record a first detected light signal;
• control the light source arrangement to provide a second signal at a second wavelength and to record a second detected light signal;
• process the first and second detected signals to derive a measure of the aerosol particle size by:
• processing the first and second detected signals to determine measurements of the obscuration at each of the first and second wavelengths;
• comparing the measurements of the obscuration at each of the first and second wavelengths to a function relating the modulation on the amount of light scattering by an aerosol flow to particle size variation;
• and
• deriving a measure of the aerosol particle size from the result of the comparison.