Laboratory animals are animals specifically bred for experimental purposes. They mainly refer to animals domesticated, reproduced, and reared for the needs of scientific research, teaching, medical treatment, identification, diagnosis, and manufacture of biological products in fields such as medicine, pharmacy, biology, and veterinary medicine. A laboratory animal facility is a building suitable for the breeding and rearing of laboratory animals. Different requirements are imposed on the design and management of the animal facility for laboratory animals of different grades. Animals that are germ - free, gnotobiotic, and specific - pathogen - free need to be raised in a sterile or as - sterile - as - possible environment.  

Common disinfection, purification and sterilization methods currently used in animal laboratories include vaporized hydrogen peroxide sterilization, ultraviolet disinfection, ozone disinfection, formaldehyde fumigation, etc. 

01 Vaporized Hydrogen Peroxide Sterilization Hydrogen peroxide (hydrogen dioxide) itself is a disinfectant. Judging from its molecular formula, it can be completely free from the suspicion of being toxic or harmful. Moreover, the sterilization process features low temperature, low humidity and high speed, which is fully in line with the development direction of future sterilization equipment. Hydrogen peroxide is a high - density oxidant, with the property of exothermic decomposition into water vapor and oxygen. Hydrogen peroxide sterilizes mainly through oxidation, and leaves no residual toxicity after decomposition. Vaporized hydrogen peroxide (H₂O₂) sterilization is divided into two types: hydrogen peroxide vapor (HPV) sterilization technology and hydrogen peroxide dry fog (VHP) sterilization technology. 

02 Ultraviolet Disinfection The bactericidal ability of ultraviolet rays varies with factors such as ambient temperature, humidity and wind speed. When the ambient temperature is 20 °C and the relative humidity is 40% - 60%, the effect is good. When the ambient temperature is 0 °C, the radiation capacity is less than 60%, and when the relative humidity is > 60%, the radiation capacity decreases. In addition, the bactericidal ability decreases with the increase of usage time, and the average lifespan of an ultraviolet lamp is about 2000 hours. In order to obtain a satisfactory ultraviolet radiation intensity, corresponding requirements need to be put forward for the glass tube, reflector cover and service life of the ultraviolet lamp. Moreover, the radiation intensity of the ultraviolet lamp weakens with the increase of the irradiation distance. Ultraviolet sterilization may cause damage to the human body. For example, direct irradiation on the eyes can cause conjunctivitis or keratitis. The WHO and EU GMP regulations state that due to the limited sterilization effect of ultraviolet rays, they cannot replace chemical disinfection; ultraviolet irradiation cannot be used for sterilization in the final sterilization process. 

03 Formaldehyde Fumigation Sterilization Taking formaldehyde fumigation sterilization as an example, when the humidity is around 65% and the temperature is between 24 - 40 °C, the disinfection effect of formaldehyde is the best. Its disinfection and sterilization principle is mainly that formaldehyde can destroy the active components of microorganisms to achieve the purpose of disinfection. Usually, formaldehyde solution is poured into potassium permanganate to disinfect the air in the clean room. This is mainly because when potassium permanganate encounters formaldehyde, it releases a large amount of heat, causing formaldehyde to evaporate and diffuse into the air. Formaldehyde vapor has a strong pungent odor, is a highly toxic substance and is carcinogenic. 

04 Ozone Disinfection Ozone (O₃) is a toxic, light - blue, unstable and extremely strong oxidant, with a relative gas density of 1.657. Ozone is a broad - spectrum and highly effective disinfectant with a strong bactericidal and disinfecting effect. Ozone is unstable at room temperature and极易 decomposes into oxygen molecules and oxygen atoms. The oxygen atoms are oxidizing and can damage the cell membranes of microorganisms, thus killing them. The excess oxygen atoms will automatically combine into oxygen molecules without producing toxic residues. The raw materials for generating ozone are oxygen and electric energy, and ozone is usually generated by an ozone generator. Ozone is a harmful gas. When the concentration is 6.25×10⁻⁶ mol/L (0.3 mg/L), it can cause a stimulating sensation in the eyes, nose and throat. When the concentration is (6.25 - 62.5)×10⁻⁵ mol/L (3 - 30 mg/L), symptoms such as headache and local paralysis of the respiratory organs will occur. When the ozone concentration is 3.125×10⁻⁴ - 1.25×10⁻³ mol/L (15 - 60 mg/L), it is harmful to the human body.