Accurate measurement of the aerosols concentration is important in many applications of aerosol science. Here we compare the adequacy of a peak function with the profiles distribution given by a particle counter (CPC) classified in the size range 5 to 500 nm, issued in a machine shop. The particle counter uses a laser source and an optical system for the detection of particles. Our experiments lead to some underestimation of the profile. This underestimation corresponds with the parasitic phenomena of air bubbles and water droplets which are recorded by default as particles. The results of this study underscore the compatibility of a function Gaussian modified by exponential with the distribution profile given by the particle counter (99%).