Activity such as manufacturing or research is conducted inside the clean room and hence, maintaining the required cleanliness may be difficult even after satisfying the conditions such as current sending method or ventilation frequency.
Pollutants causing lowering (of cleanliness) must be appropriately managed for maintaining the quality of cleanliness.
As is understood from the above table, the biggest source of pollution inside the clean room is workers. As the concrete examples, particles generated from insulation part such as clothes etc., particles generated by activity such as breathing etc. can be given. It is said that humans generate 100,000 fine particles having diameter of 0.3 μm when standing still and about 500,000 fine particles when lightly moving an arm etc.
It is important to reduce coming – going inside empty room that requires cleanliness, to reduce unnecessary operation, to create layout design where there is no operation near work and to create entry – exit manual, in order to prevent pollution by workers.