Dust particles and microbial contamination in cleanroom

Cleanroom can be classified into industrial cleanroom, bio-medicine cleanroom, biosafety cleanroom. The industrial cleanroom mainly controls the inactive dust particles and maintains the relative positive pressure on the adjacent room. It is suitable for electronic industry and precision industry and so on. The bio-medical cleaning room mainly controls the pollution of living particles and dust particles to the working objects. Except that the internal materials must be used to withstand the erosion of various fungicides, it is the same as the industrial cleanrooms. Biosafety cleanroom is different from general cleanroom only because its interior need to maintain negative pressure on adjacent room. Obviously, for non-biological drug manufacturing enterprises, the cleanroom should be controlled according to the bio-medicine cleanroom.


The source of dust particles and microorganism in bio-medicine cleanroom is divided into external pollution and internal pollution.

At present, the control of external pollution is mainly accomplished by air conditioning three-stage filtration system and pressure difference control in cleanroom; microorganisms include: virus, rickettsia, bacteria, fungi, protozoa. But the cleanroom is related mainly to bacteria and fungi. Bacteria can not survive alone, generally attached to the dust particles, so the air conditioning three-stage filtration system and pressure difference control not only complete the dust particle barrier, but also complete the bacteria barrier.

Internal pollution sources in cleanroom

Internal pollution sources mainly refer to the amount of dust emitted in a cleanroom. Mainly include: equipment dust, products, materials during the production process , building, craft equipment, piping and other surface dust, human dust.

  1. Dust from equipment can be removed by local exhaust, so that it does not flow into the indoor;
  2. Compared with the amount of dust carried by human body, the amount of dust emitted during transportation of products and materials is generally very small and Can be ignored
  1. Due to the application of color steel sandwich plate, PVC floor, epoxy self-leveling, stainless steel plate, stainless steel pipeline, stainless steel bridge and other materials, the dust from the building surface is also very little, generally accounting for less than 10%.
  2. About 90% of human dust. In terms of the amount of human dust, the amount of human dust can be reduced through the management of personnel dress, the improvement of clothing material style, the control of personnel number and the management of personnel activity area.

Quantity of bacteria in cleanroom

For the quantity of bacteria, the analysis of foreign experimental data can be considered as follows:

  1. When workers wear clean clothes in cleanrooms, the bacterial quantity is generally 10-300 per person per minute at rest. 150-1000 per minute per person during general physical activity and 900-2500 per minute per person during fast walking.
  2. The amount of bacteria per cough is 70-700 per person per minute. And per sneeze is 4000-62 000 per person per minute.
  3. The ratio of bacterial quantity with and without masks is 1:7-1:14.
  4. When wearing ordinary clothes, the bacterial count ranged from 3300 to 62000 per minute per person
  5. The ratio of the amount of bacteria to the amount of dust generated is 1:500 to 1:1000

Therefore, article 20 of Appendix 1 to the new version of GMP (draft for comments) provides that: “the number of persons in the clean area shall be strictly controlled. And the inspection and supervision shall be carried out as far as possible outside the clean area of sterile production;” Article 23 states that high standards of personal hygiene are extremely important. Employees involved in the production of sterile drugs should be instructed to report at any time any anomalies that may cause pollution. Including the type and extent of contamination. When health conditions may increase the risk of microbial contamination, the designated person shall take appropriate measures.

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