The Particle Size Magnifier (PSM) from AIRMODUS grows nano-sized particles to bigger particles that can then be detected by a Condensation Particle Counter (CPC).
The growth of small particles
The air sample is mixed with a heated clean air flow that is saturated with a fluid (diethylene glycol). Because of the mixing of the two air flows with different temperatures and the saturation fluid, the seed particles start to grow through condensing the fluid onto their surface. Now they have a proper size and can be led to the CPC.
Measuring the grown particles
After leaving the PSM the particles have a size of ~90 nanometers, which is still to small to detect optically. Therefore the particles pass through a second growth process inside the condensation particle counter, CPC. The air flow coming from the PSM is heated and saturated with another fluid (e.g. Butanol). Then the flow is cooled down again which enables the fluid to condense onto the particles and makes them optically detectable.