Advanced laminar flow water condensation technology for ultrafine particles

A method for creating water vapor supersaturation in an airflow, comprising:

• introducing an airstream in a laminar flow into a wet-walled condenser, the airstream having an inlet temperature T1 at the inlet of the condenser, the condenser having an outlet;
• controlling a first portion of the condenser having a length and being adjacent to the inlet to a first temperature T2 greater than T1 by at least 5° C.;
• and
• controlling a second portion of the condenser between the first portion and the outlet at a second temperature T3 lower than T2;
• wherein the first portion and the second portion of the condenser define a volume, and the airstream flows through the condenser in a laminar manner, wherein introducing the airstream into the condenser creates a volumetric air flow rate within the volume, the volume having a cylindrical geometry or a multiple plate geometry wherein each plate has a width and a separation between plates;
• wherein for a cylindrical geometry the length of the first portion divided by the volumetric flow rate is less than 0.5 s/cm2 and for a multiple plates geometry a quantity of the length of the first portion divided by the volumetric flow rate multiplied a quantity of the width divided by the separation is less than 0.5 s/cm2.