| CPC G01N 15/065 (2013.01) [G01N 15/06 (2013.01); G01N 15/075 (2024.01)] | 21 Claims |
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1. A method for measuring a concentration of particles in air, comprising
introducing an air sample into a particle chamber through an inlet;
closing the inlet to isolate the particle chamber;
exhausting the air sample in the isolated particle chamber through a nozzle connected to an optical detector, said exhausting of the flow performed at a flow rate chosen to cause an expansion of any of the air sample inside the particle chamber, reduce a temperature of the any of the air sample inside the particle chamber, increase a relative humidity of any of the air sample inside the particle chamber, and cause vapor to condense on particles suspended in the any of the air sample inside the particle chamber, thereby forming droplets;
counting the droplets in the air sample as it is exhausted through the optical detector;
measuring a pressure from which an amount of air exiting the chamber can be assessed; and
determining a particle concentration as a ratio of a number of droplets detected to the amount of air that has exited the chamber based on the counting and the measuring.
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