In order to combat the spread of the new coronavirus, people have snapped up various anti-epidemic products. In addition to the continued hot sales of masks, alcohol, and dry cleaners, various home appliances equipped with UVC ultraviolet germicidal lamps have also become the focus of snapping up.
Ultraviolet rays are divided into UVA (320-400nm), UVB (280-320nm) and UVC (100-280nm) according to their wavelengths. Among them, the UVC wavelength ultraviolet lamp emits ultraviolet light to destroy the DNA or RNA molecular structure of the microbial cells, so that the bacteria or viruses die, and the effect of sterilization and disinfection is achieved. According to research, UVC ultraviolet light has the strongest bactericidal effect at a wavelength of about 250-260nm.
At present, the ultraviolet light source used for medical sterilization mainly comes from the ultraviolet mercury lamp. The mercury lamp adds mercury (mercury) to the vacuum quartz tube, and discharges through the voltage difference between the two ends of the electric shock, which excites ultraviolet radiation waves, and then changes the wavelength through the fluorescent paint inside the tube.
The sterilization application of ultraviolet light LED (UVCLED) has gradually attracted attention. UVCLED emits ultraviolet light through power conversion through solid-state semiconductor components, and the wavelength can be adjusted through technology. At present, the radiation intensity of UVCLED is about 2mW to 100mW.
The sterilization effect of UVC ultraviolet light depends on the radiation intensity (and illuminance) of the ultraviolet light and the irradiation time, which are combined into the irradiation dose. The stronger the illuminance, the shorter the required irradiation time. On the contrary, if the illuminance is low, a longer irradiation time is required to meet the same light dose and achieve the sterilization effect.
At present, the main reason why UVCLEDs cannot completely replace medical sterilizing ultraviolet mercury lamps is that the brightness of UVCLEDs is still not strong enough. To achieve the same sterilization effect as mercury lamps, a larger amount of UVCLEDs or more time will be needed. For professional medical units with high frequency of use and a large range of sterilization space required, it is not cost-effective to use UVCLED for sterilization at this stage.
However, UVCLED has gradually begun to play a role in the sterilization of general daily use. Compared with the ultraviolet mercury lamp, the light source of UVCLED is smaller and can be used in different applications. It is embedded in the product and has high portability. At present, the most common applications are mainly air sterilization, static and flowing water sterilization.
As for whether it is useful to use UVC ultraviolet light to combat the new coronavirus COVID-19, which is currently raging around the world, there is currently no clinical trial to prove it. In the past, experiments were conducted on the SARS virus, which is also a coronavirus, and the results indicate that the coronavirus can be eliminated under sufficient UVC ultraviolet light dose irradiation. However, different environmental factors, including humidity, temperature, etc., will also affect the sterilization effect of UVC ultraviolet light. Current experiments have not been able to establish complete data and establish the light dose that can kill the virus. In other words, the effectiveness of UVC ultraviolet light for eradicating the new coronavirus needs to be further confirmed at this stage. When using various disinfection and sterilization lighting products on the market, you should still pay attention to timely hand cleaning and avoid touching your eyes with your hands. Mouth and nose can strengthen epidemic prevention.
