Design and Evaluation of a Condensation Particle Counter with High Performance for Single-Particle Counting

A full-flow butanol-based condensation particle counter (CPC) with a concentration range from 0 to 2 x 10(5) particles/cm(3) was developed to measure nanoparticles down to 4.5 nm. Good single-particle counting performance was achieved by developing a high-speed optical particle detection module. The pulse width of single particle was approximately 1.2 mu s at a flow rate of 0.3 L/min. By establishing a heat and mass transfer model using the COMSOL simulation software, the effects of temperature and aerosol sampling flow on the condensation growth of nanoparticles were studied. The performance of developed condensation particle counter was evaluated through a series of experiments to determine the coincidence probability, concentration range, and detection efficiency (cutoff diameter). At concentrations of 1.5 x 10(4) particles/cm(3) and 2 x 10(5) particles/cm(3), the coincidence probabilities of the developed condensation particle counter were 9.5% and 55%, respectively. A 99.9% (R-2) statistical correlation was obtained between the pulse-time corrected concentration of the developed condensation particle counter and the standard reference concentration. Finally, the experimental results showed that the developed condensation particle counter cutoff diameter, at which the detection efficiency was 50%, for sucrose aerosol particles was 4.5 nm.