As mentioned above, the levels of cleanrooms are generally divided into four levels: M3.5 (100), M4.5 (1000), M5.5 (10000), and M6.5 (100000). However, the necessary levels are different depending on the different work processes in each industry. For example, in semiconductor manufacturing plants, cleanrooms of M1 (10)-M5.5 (1000) are required according to the work content. Moreover, in pharmaceutical factories, cleanrooms of a wide range of levels from M3.5 to M6.5 (100,000) are required according to the purity of the product and the work process. Therefore, the cleanrooms required by various industries have different cleanliness requirements.
| Fields and Industries | Cleanliness standard (level) | content | ||
| SI | English Unit | |||
| Semiconductor industry (IC\LSI, etc.) | Mask template alignment process | M3.5 | 100 | |
| Etching process | M3.5 | 100 | Etching processing | |
| Dispersion process | M3.5 | 100 | High-purity diffusion | |
| Evaporation process | M3.5 | 100 | High-purity electroplating | |
| Coating process | M3.5 | 100 | Photosensitive agent coating | |
| Electronic equipment | Calculator manufacturing; | M5.5 | 10,000 | Magnetic head |
| cathode ray tubes; | M5.5 | 10,000, | Shielding | |
| magnetic tapes; | M5.5 | 10,000 | Preventing noise | |
| Precision instruments | gyroscopes, miniature bearings; | M5.5 | 10,000 | Improving precision |
| missile parts, relays; | M5.5 | 10,000 | Preventing malfunction | |
| clocks, small measuring instruments | M5.5 | 10,000 | Assembly, packaging, repair | |
| Optics, printing | Cameras, printed circuit boards; | M5.5 | 10,000 | Manufacturing |
| Lenses, films; | M4.5 | 1,000 | Connection | |
| Electronic plate making; | M5.5 | 10,000 | Manufacturing, inspection | |
| Chemicals | Filling of injections; | M3.5 | 100 | Blending, filling |
| Sterile animal breeding; | M3.5 | 100 | SPF | |
| Chemicals | Antibiotics; | M5.5 | 10,000 | Filling, inspection |
| General medical products; | M6.5 | 100,000 | Manufacturing | |
| Food | Brewing, fermentation; | M5.5 | 10,000 | Preventing soy sauce and soybean paste from spoiling |
| Dairy products, raw foods; | M5.5 | 100,000 | Preventing yogurt from spoiling | |
| Meat processing; | M6.5 | 10,000 | Ham and sausage | |
| Blending (mixing into paste) foods; | M5.5 | 10,000 | Prevent bacteria from adhering to cylindrical or semi-circular fish, fish and sweet potato balls that are stirred and baked during refrigeration. | |
| Medical | Operating rooms; | M3.5 | 100 | Hip joint surgery, organ transplantation |
| Special treatment rooms; | M3.5 | 100 | Leukemia, burns | |
| Recovery, neonatal rooms; | M3.5 | 10,000 | Premature infants, postoperative infection prevention | |
| Clinical examinations; | M5.5 | 10,000 | Fungus cultivation, inspection | |
| Agriculture and animal husbandry | Mushroom cultivation; | M5.5 | 10,000 | Preventing mushrooms from being infected by foreign bacteria |
| Plants; Farming; | M6.5 | 100,000 | Orchid cultivation (sterile plants for experiments, strong cultivation plants) | |
| General pathogens; | M5.5 | 10,000 | Preventing fish and silkworms from dying from bacterial invasion | |
| Microorganisms | Common virus pathogens | M3.5 | 100 | Marburg virus, Lassa fever, Ebola hemorrhagic fever (exhausting air) |
| Gene conversion | M3.5 | 100 | Escherichia coli (exhausting air) | |
