A system for detecting particles, including: a first device to measure concentration of particles, including an electrometer measuring device coupled to a charger and/or to an optical particle counter; a second device to measure concentration of particles, including a condensation nuclei counter; a calculation unit configured to calculate a ratio and/or a difference between a first measurement of the particle concentration in an airflow, to be performed by the first measurement device, and a second measurement of the particle concentration in an airflow, to be performed by the second measurement device, and configured to provide a comparison between the ratio and/or the difference between the first and second measurements and a threshold value to determine presence of particles of interest other than ambient air particles.