System and method for analyzing size distribution and chemical composition of neutral clusters below 3 nm

A system for analyzing the size distribution and chemical composition of neutral clusters below 3 nm, comprising a sampling device, a unipolar charging device, a first coupling transport device, a nanoparticle electrical mobility size classification device, a second coupling transport device, a mass spectrometer, an aerosol number concentration measuring device, and a system control device,

• wherein the sampling device, the unipolar charging device, the first coupling transport device, the nanoparticle electrical mobility size classification device, the second coupling transport device, and the mass spectrometer are sequentially connected along a particle inlet direction,
• the second coupling transport device is connected with the aerosol number concentration measuring device, and
• the system control device is in signal communication with the sampling device, the unipolar charging device, the nanoparticle electrical mobility size classification device, the mass spectrometer, and the aerosol number concentration measuring device,
• wherein the first coupling transport device is configured to establish a stable and uniform reverse electric field so as to suppress interference caused by a local high-intensity electric field at an inlet of the nanoparticle electrical mobility size classification device on charged particles;
• and
• wherein the second coupling transport device is configured to provide a particle transfer passage having an inner diameter the same as that of an outlet of the nanoparticle electrical mobility size classification device, so as to reduce particle loss caused by a mismatch in tube dimensions and/or flow field disturbances.