Can ultraviolet lamps kill viruses? The doctor said that medical evidence data is not enough, and it is still necessary to disinfect the environment with frequent hand washing, alcohol or bleach. (Data photo, photo by reporter Luo Qi)
[Health Channel/Comprehensive Report]The Wuhan pneumonia (new coronavirus disease, COVID-19) epidemic has spread, and the sterilization and disinfection equipment has been smashed to the point. Many people are wondering whether the use of ultraviolet lamps and other related products can kill the virus. ? The doctor said that it may be effective, but the current medical evidence is insufficient. It is still necessary to disinfect the environment with frequent hand washing, alcohol or bleach. It cannot be assumed that disinfecting the environment with ultraviolet light is safe. Improper use may cause harm to the human respiratory tract!
Yan Junyu, Director of Pediatrics Department of Taipei Veterans General Hospital Taoyuan Branch, on Facebook fanShuangbao Dad’s Little Universe-Dr. Yan Junyu, Department of Pediatric InfectionsAccording to the article, “UVC” refers to ultraviolet light with a wavelength of 100-280nm. The strong energy can destroy the DNA of microorganisms. It can be used for air disinfection and surface disinfection of objects. It is effective against most bacteria, viruses, and molds. Although sunlight has Most of the UVC that has a sterilization effect is absorbed by the ozone layer, so it cannot be sterilized by sunlight. The same reason can be proved that Southeast Asia, where the sun is shining, cannot escape the clutches of COVID-19. Outdoors in the sun are mainly exposed to UVA. 95% will cause skin aging, wrinkles and UVB 5% will cause skin redness, heat, and skin cancer.
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There is a set of UV lamps, don’t disinfect the human body
Yan Junyu explained the special effects of different wavelengths of UVC, 254nm is the most commonly used, 15.54 (mW/cm2) energy, 1 minute of irradiation to kill most bacteria; 207-222nm is less harmful to human skin and eyes; 185nm will excite oxygen into ozone. UVC has poor penetration and cannot penetrate dust, soil, and body fluids. Paper, glass, and fog will also greatly reduce the intensity of radiation. If germs are hidden on the surface with holes, it will not be illuminated, and the backlit surface of the object will have no effect; Remind the public that UVC may irritate or burn the skin or damage the cornea of the eyes, but due to its weak penetrating power, it rarely causes skin cancer or cataracts.
Yan Junyu said that when the lamp emits UVC with a wavelength of 185nm in ultraviolet light, it will stimulate the oxygen in the air to turn into ozone. The quartz glass tube with special ingredients can effectively control the amount of UVC with a wavelength of 185nm to control the amount of ozone, which can also diffuse Sterilize in places out of light; he also reminded that the average allowable exposure value of indoor ozone for 8 hours is 0.1ppm. If it exceeds, it may cause respiratory irritation, asthma, and respiratory tract fragility, which may increase the chance of respiratory tract infection.
Yan Junyu reminds the public about the precautions for the use of UV lamps for public reference:
●Ultraviolet lamp cannot be used for human body disinfection.
●Do not be in the same room during disinfection.
●For those with ozone function, it is best to ventilate for 30-60 minutes after irradiation.
●Refer to the recommendations for the irradiation time of each UV lamp: preferably 30-60 minutes or more.
●Pay attention to the space range of effective irradiation: 15 watts irradiation range is 2.8 pings, 30 watts irradiation range is 5.6 pings.
●Wipe and clean the lamp tube: so as not to affect the performance of dust, cause the aging of plastic or silicone material, and the discoloration of dyed items.