Abstract: A nanoparticle size classifier comprising a variable flow rate system with a single diffusion element 3 placed inside a cell 2 containing inlet 1 and outlets 6 and 7, an aerosol filter 8, flow meter 9, pump 10 and pump controller 11, which enables a plurality of measurements to be obtained by means of passing an aerosol through the diffusion element 3 at various flow rates. Preferably, outlet of the diffusion cell is connected to a particle counter 5 via a three-way valve 6. The diffusion element has a net or screen that permit air through but capture some particles. In a preferred embodiment, the nanoparticle size classifier is connected to a PC 12 (a notebook or a palm-size computer) to acquire and process data.

Abstract: The invention provides an apparatus for increasing the size of gas-entrained particles in order to render the gas-entrained particles detectable by a particle detector, the apparatus comprising an evaporation chamber (2) and a condenser (7); the apparatus is configured so that vapour-laden gas from the evaporation chamber can flow into the condenser and condensation of the vaporisable substance onto gas-entrained particles in the condenser takes place to increase the size of the particles so that they are capable of being detected by a particle detector.