Cleanroom Monitoring
A cleanroom is a controlled environment with an installation that removes airborne particles by air flow and does not introduce particles by this air flow. Not all particles > 5 µm are removed by air flow because of deposition on all surfaces. The number of particles that are not removed because of deposition increases with particle size (50 % for particles > 80 % for particles > 25 µm and >90 % for particles > 40 µm).
The resulting air cleanliness for all particle sizes during operation (when people are working in the cleanroom) can be monitored by measuring the concentration of airborne particles up to 5 µm and by measuring the particle deposition of particles > 5 µm and the resulting surface cleanliness at critical locations.
