UV light is electromagnetic radiation having a wavelength between that of visible light and X-ray. It reaches us through sunlight and can be produced artificially through specific lights and electric arcs by adjusting the wavelengths. UVC has mixed effects on humans, both good and bad. UV light kills bacteria, viruses, germs, and other harmful microorganisms by scrambling the nucleic acid and hindering further reproduction and replication. But it is also detrimental to human skin and eyes; it causes skin cancer, cataracts, and other skin sensitivities when it comes to direct contact for a long time with human skin.
Initially, after the realization that sunlight contains such radiation, which is useful for purifying and disinfecting water and other objects, UV light was used in different ways but without precautions and knowledge of how it works and other benefits. Then scientists discovered a certain wavelength that can be used to quickly and effectively kill germs without harming human skin. UV light was used mainly in hospitals and important public places, but with the advanced discoveries and easy availability of new technology, UV is used commonly at homes to decontaminate household objects and at offices for safety purposes.
Many people do not know how UV evolved to the form and shape of today and how it gained popularity as a chemical-free disinfection method. UV sterilization has a long and interesting history, and people of old times even admitted its effectiveness. In ancient times, it was culturally and traditionally rooted in people that sunlight is a symbol and source of health, warmth, and cure. They had no understanding of the scientific basis of this mythology.
In the late 17th century, people tried to find some scientific basis to explain this phenomenon of sunlight and its effects. With the scientific revolution, people became restless in finding out the answer to this curative nature of the sun. With the beginning of the 19th century, the multiple experiments led to the realization that sunlight is not composed of single radiation, but the combination of different lights with distinct wavelengths.
In 1803, a German physicist, Johann Wilhelm Ritter, discovered UV light while observing its unique property of darkening silver chloride-soaked paper speedily than violet light and determine the wavelength of this invisible light shorter than violet light. In order to differentiate this newly discovered light from heat rays and because of high reactivity, he named them as oxidizing rays. After a few years, people gave it a simpler name as chemical rays, which remained popular throughout the 19th century. This invisible light was eventually given the name of Ultraviolet light, which is retained until now. In 1878, two scientists Arthur Downes and Thomas P. Blunt, explained how UV light with short wavelengths could perform sterilization by attacking the DNA of the bacteria through the publication of their papers.
In 1903, Niels Finsen was awarded a Nobel Peace prize for treating tuberculosis and lupus vulgaris with UV light. At the same time, different effects of different wavelengths were determined, and UVC was declared harmful but the most penetrative and powerful type of UV. In 1910, UV sterilization was used to purify drinking water in Marseille, France. During and after the 1920s, there was rapid and extensive researches and studies on UV light. In the 1930s, tubular lamps were introduced for convenience and easy use.
1995 saw the rapid and fast spread of UV water disinfection in Europe when in Austria and Switzerland, this new technology was employed. By the 1960s, UV water treatment became commercial, and markets were flooded with UV devices.
Now UV devices come in different and unique shapes to be used in homes, schools, hospitals to avoid contraction of diseases through viruses and germs present on surfaces.