What is Ultraviolet Light?
Ultraviolet light is a type of naturally present electromagnetic radiation that is in sunlight and actually makes up approximately 10% of the total light generated by the sun. UV light is electromagnetic energy with wavelengths shorter than visible light but longer than x-rays. The wavelength of this light ranges from 10nm to 400nm and is classified into three sub-bands; UV-A (near), UV-B (middle), and UV-C (far).
UV light with wavelengths less than 290nm are considered to have “germicidal” properties (more on this later). Earth’s atmosphere absorbs ultramagnetic radiation with wavelengths less than 290nm, meaning that most of the UV-C and UV-B generated by the sun is blocked by our planet’s ozone.
How does UV Light Kill Viruses and Bacteria?
Ultraviolet light kills cells by damaging their DNA. Exposure to the electromagnetic radiation (light) at certain UV wavelengths modifies the genetic material of microorganisms and destroys their ability to reproduce. The UV energy triggers the formation of specific thymine or cystosine dimers in DNA and uracil dimers in RNA, which causes the inactivation of microbes by causing mutations and/or cell death as well as failure to reproduce.
According to this from the Centers for Disease Control (CDC), “UV can kill all bacteria, including drug-resistant bacteria because UV light is actually attacking the DNA and RNA of microbes. While the amount of UV needed to kill a microbe may vary as there is a relationship between the size of DNA molecules and the effect of UV radiation, there have been no reports of microbes demonstrating an ability to build an immunity to light-based methods.”
Will it work on Coronavirus?
COVID-19 is a new breed, and as such there is a dearth of studies on its resistance to UV. That hasn’t stopped people from rolling out UV devices to thwart the virus, a concentrated form of UV is now on the front line in the fight against Covid-19, Companies that produce UV devices are seeing a notable boost in sales, In China, whole buses are being lit up by the ghostly blue light each night, UV-emitting robots have been cleaning floors in hospitals and banks have even been using the light to disinfect their money.
Although UV is effective in killing the virus indoors, UV lamps should not be used to sterilize hands or other areas of skin, as the radiation can cause skin irritation.
