Patent ID: 7549318

Claim:
A method for measuring an integral total number concentration of particles in an aerosol, wherein the aerosol contains particles of an unknown size distribution, the method comprising the steps of: electrically charging the aerosol by way of diffusion charging to create charged aerosol particles; measuring a diffusional precipitator current which is caused by at least some of the charged aerosol particles being precipitated in a single diffusional precipitator or in a plurality of diffusional precipitators connected electrically in parallel or in a plurality of diffusional precipitators arranged in parallel with regards to an aerosol flow, and evaluating a value for the integral total number concentration based on a result from said measurement, wherein the said diffusional precipitator current is measured from a single diffusional precipitator and is the only diffusional precipitator current used in said step of evaluating the value of the integral total number concentration.