Can UV light be used to disinfect hands?

May 07, 2020   Myth Vs Truth

Can UV light be used to disinfect hands?

Everyone is looking for easier and comfortable ways to keep their hands clean and virus free now. And a new technique has come up and is spread a an easier way than washing hands with soap or rubbing hand sanitizers. The method is to sanitize hands with UV light. Can UV light sanitize your hands and make it germ or virus free?


Let us take a look at UV light in detail. UV light is the band of light whose wavelength comes shorter than violet in the visible spectrum. The wave length varies from 10nm to 400nm and is not visible to the human eye.

There are 3 separate spectrum of UV light. Ranges below that are absorbed by the atmosphere.

UVA (400nm - 315nm)                                                                                                                    

UVB (315nm - 280nm)                                                                                                                   

UVC (280nm - 100nm)

UVA light is what mostly makes up the UV radiation reaching Earth’s surface from sun. These are not immediately harmful to human skin. But these are responsible for skin again and spots.

UVB can damage our skin, causing sunburn and eventual skin cancer. These can be blocked by using good suncreams.

UVC is more energetic spectrum of UV. These does not reach the Earth surface owing to the  ozone layer in atmosphere. But these are capable of destroying genetic material, be it human or germicides. In 1878, scientists discovered that they could harness UVC rays to destroy germs/ bacteria and viruses. But these are extremely harmful to humans. Any contact to skin or eyes could have the same effect in seconds as exposure to UVB for hours. It is dangerous to humans.

UVC are being extensively used in hospitals, airplanes and factories for sterilization and needs to be handled with extreme care.

Now, what is the UV light that makes thing glow at parties? It is UVA that causes fluorescence in objects. These have no germicidal properties.

A variation of this UV spectrum has been used for fast drying in manicure and hand wash facilities but, these again does not kill germs on your hand.

New research speaks about far UVC spectrum that comes between 200nm and 122nm that is said to kill germs and viruses, but not powerful enough to penetrate human skin. Research is still in progress.

Normal UVA light can be produced with a flash light passed through some materials like fused quartz or fluorite. These has the fluorescent features but not germicidal.

The only disinfecting UV rays are UVC and these are harmful to humans.

Please be extremely careful handling these equipments and avoid exposure to skin or eyes.


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