Pulsed condensation particle counter

Abstract

A method and apparatus to create water vapor supersaturation and particulate counts from an air sample. The method and apparatus include introducing an air sample into a chamber by passing a flow into the chamber through the inlet by pumping at the outlet. The method further includes closing the inlet while continuing the pumping to exhaust the air sample from the chamber through the outlet. The pumping is performed at a rate operable to reduce pressure inside the chamber such that the air sample in the central portion of the chamber cools, and water vapor from walls of the chamber has time to diffuse into the air sample in the chamber from the walls. The cycles are repeated by continuously repeating the introducing and closing. The walls of the chamber may be wetted or dry.

Description

[0001] Cross References to Related Applications [0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 830,346, filed April 5, 2019. [0003] government rights [0004] This technology was made with support from the U.S. Department of Energy, STTR grant number DE-SC0020496 and the National Institutes of Health grant number OH10515. The government has certain rights to the technology. technical field [0005] The technique involves the measurement of particles suspended in air or other gases. Background technique [0006] Atmospheric particles in the ultrafine size range (roughly defined as particles with diameters between 5nm and 100nm) are ubiquitous in urban air. Inhalation of these particles is considered a health risk and has been linked to shortened human lifespan. Furthermore, ultrafine particles are a major contributor to the total number of particles found in the atmosphere. Some ultrafine particles grow so rapidly that they c...

AI Technical Summary

Problems solved by technology

The method includes introducing an air sample into the particle chamber via an inlet and closing the inlet to isolate the particle chamber

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