China's standard on the classification of clean operating departments clearly indicates that its control objects include four aspects:

(1) Both bacterial concentration and air cleanliness class must be controlled, i.e., both must meet the standard.

(2) For bacterial concentration, either airborne bacterial concentration or settling bacterial concentration may be selected for control, i.e., meeting the standard in either one is accepted.

(3) For air cleanliness class, both particle sizes of ≥0.5μm and ≥5μm are controlled, i.e., if either particle size fails to meet the standard, it is not accepted.

(4) Static data are used for acceptance control, and dynamic data are used for routine supervision control.