How Does UV Light Kill Bacteria?

Shares & Saves


Who Uses UV Light Sterilization

  • Ultraviolet radiation is used to kill microorganisms, molds and fungi in various environmental applications. UV sterilization is used for air-purification systems, water purification, aquarium and pond maintenance, laboratory hygiene and food and beverage protection.

When to Use UV Light Sterilization

  • Ultraviolet sterilization is useful for targeted elimination of microorganisms in air and water. UV sterilization leaves no residual chemical or radiation in the air or water and does not harm untargeted animals and plants. The treatment works well with waterborne pathogens but does not remove chemical or heavy metal impurities. Water should be filtered prior to UV exposure to improve the sterilization effect. Sterilized microorganisms remain in the air or water.

Where to Use UV Light Sterilization

  • Because direct exposure to strong ultraviolet light can cause blindness and skin burns to people and animals, sterilization generally takes place in shielded UV hoods or light-proof UV chambers. UV treatment works well in applications where bacterial contamination poses a problem in air or water in aquariums, ponds, laboratories and clean rooms.

How UV Light Sterilization Works

  • Ultraviolet light kills microorganisms by damaging their DNA. UV radiation disrupts the chemical bonds that hold the atoms of DNA together in the microorganism. If the damage is severe enough, the bacteria cannot repair the damage and the cells die. Prolonged exposure to UV light helps ensure complete kill-off of all microorganisms. Unlike chemical treatments, however, UV-treated air or water does not resist re-contamination.

Why Use UV Light Sterilization

  • Ultraviolet light penetrates the cells, but does not alter the water, air or food being treated. Nothing is added to the medium except energy. Dead bugs also are not removed from the sterilized medium. Nor are organic or inorganic particles in the water or air. Some organisms, like certain molds, are not as affected by UV radiation. UV radiation is indicated in situations where chemical residue after sterilization is not acceptable



  • Photo Credit Aleksdem/iStock/Getty Images

You May Also Like

Read Article

3 Tips to Get Better Beauty Sleep