Destroying Germs with the Power of Light

By WPG AmericasJanuary 8, 2019

The disinfecting powers of sunlight have been known to mankind for ages. Over the last century, it has been proven, time and again, that sunlight — particularly the ultraviolet (UV) rays — can kill a wide range of bacteria.

The disinfecting properties of sunlight lie specifically in the UV spectrum, which makes up nearly 10% of the total solar light output. UV rays are also the part of sunlight that’s associated with sunburn and skin cancers. 

Interestingly, UV light is invisible to the naked eye. Its wavelength ranges from 10nm and 400nm, which is shorter than visible light but longer than X-rays. UV light is divided into three sub-bands — UV-A, UV-B, and UV-C. It is the UV-C wavelength that has sterilizing powers and is used to kill germs in water and air, as well as on surfaces. UV-B also has some germicidal properties, while UV-A is used in curing and printing.

Why UV Disinfection?

Chemical treatments, using chlorine and ozone, have been the most prevalent disinfection method, and continue to be the primary means of general disinfection and water purification in many parts of the world. Chemical treatments, however, can have adverse effects because of their toxic and corrosive nature. Most importantly, chemical disinfection is not effective against all pathogens (for example Cryptosporidium is a waterborne parasite which is extremely resistant to chlorine).

UV disinfection is a chemical- and toxin-free alternative that works just as well, or even better than chemical treatments (UV water purification can effectively destroy 99.9% of waterborne microorganisms). Furthermore, there are many industries (like food and beverage, for instance) where it is critical to meet high levels of surface disinfection without the use of chemicals. UV light provides a safe and effective sterilization solution in such cases. 

Demand for Artificial UV Sources

Although natural sunlight has remarkable germicidal capabilities, thanks to unpredictable weather conditions, it is not a fully reliable source of UV light. This is where artificial UV sources such as UV lamps come in. Just like the visible portion of the spectrum, UV light can be generated by artificial means such as UV lamps – which can be deuterium gas discharge lamps, mercury arc or vapor lamps – and of course, LED luminaires. Because they are more precise, effective, and consistent than natural solar light, artificial UV sources are being used in most applications that rely on UV light.  

While mercury arc lamps have been the most widely-used artificial UV lamp sources, they are now being outperformed by UV LEDs. By switching to LED, OEMs of water purification systems and sterilization equipment are enjoying the standard benefits of LEDs — namely, energy efficiency, longer lifespan, compact form, and mechanical robustness. Plus, they can circumvent the financial, legal, and ethical liabilities that may arise from using hazardous materials like mercury in their products. 

To know more about the major UV LED applications and supporting LED modules brought to the market by LG Innotek, download our new white paper.