Surface Particle Measurements
A cleanroom is classified as controlled on air cleanliness in terms of the concentration of airborne particles. In a cleanroom large quantities of clean air are used to remove airborne particles. The result leads to certain air cleanliness (Air cleanliness by particle concentration, ISO 14644-1:2015). This air cleanliness is used to classify a cleanroom. The classification is based on the number of particles larger or equal to >= 0.1 µm per m3.
The ISO 14644-9 document describes the classification of particle contamination levels on solid surfaces in cleanrooms and associated controlled environment applications.