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The antibacterial effects of ultraviolet (UV) light were first discovered over 140 years ago by Downes & Blunt in 1878. They observed that sunlight prevented the growth of microorganisms inside a tube and, upon increased exposure durations, the test tubes remained bacteria-free for several months. Following this they determined that shorter wavelengths of the solar spectrum were more effective at neutralizing bacteria. 

With some fantastic advancements in science, we now know much more about the germicidal effects of UV-C, UV-B, UV-A and violet blue light. Modern day UV-C lamps are highly effective for air purification, water disinfection, and surface sterilisation in a range of different applications. As specialist suppliers of UV lamps and germicidal lamps, we’ve put together this guide to answer the question ‘how does UV light kill germs’? 


How UV Light Kills Germs 

UV light kills cells by damaging their DNA. The light initiates a reaction between two molecules of thymine, one of the bases that make up DNA. DNA is the genetic material that makes up all living organisms, controlling their growth, development, functioning and reproduction. UV light produces electromagnetic energy that can destroy the ability of microorganisms to reproduce and cause inactivation of microbes by causing mutations and/or cell death. 

So what’s the science behind this? Well UV light causes damage to the nucleic acid of microorganisms by forming covalent bonds between certain adjacent bases in the DNA. When these bonds form, the organism is incapable of reproducing – In fact when the organism does try to replicate, it dies. The most effective wavelengths to achieve this effect are found between 263nm to 275nm, and the peak wavelength distribution is dependent on the target organism.

The effectiveness of UV light for killing germs depends on the length of time a microorganism is exposed to UV, the intensity and wavelength of the UV radiation, the presence of particles that can protect the microorganisms from UV, and a microorganism’s ability to withstand UV during its exposure.


Is UV Light Safe For Killing Germs? 

If UV light is not used or implemented correctly, direct exposure can have damaging effects on both materials and people. Overexposure to UV-C lighting and improper usage can harm humans in a variety of ways, such as eye and skin damage. It can also cause damage to materials, such as the erosion of rubber gaskets or plastics. Always follow the guidance from the manufacturer to ensure you are using UV light safely.

Due to these potential negative side effects of UV-C disinfection lighting, it is vital that appropriate products are utilized in the right applications where they can provide benefits. Special equipment and training is required to use UV lighting professionally in public settings. Generally, the purchase of the special equipment will provide you with the instruction needed.


ELC Lamps Online

ELC are specialist suppliers of Philips and Osram UV-C light bulbs and lamps. Osram and Philips have a strong reputation for producing high-quality UV lamps and germicidal lamps. They provide almost constant uv output over the useful lifetime of the lamp – ideal for highly effective sterilisation and purification. We supply UV lamps for homes, businesses, hospitals, GPs, schools, and much more.

Click here to browse our full range of UV lamps, or shop by category using our dropdown menu at the top.

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