UV-C lights are utilized in various industries because of their germicidal effects. The UV-C light inactivates pathogens by destroying their nucleic acids and disrupting their DNA structure, rendering them unable to perform vital cellular functions, including reproduction. Hospitals have been using UV sources for a long time to disinfect surgical suits and reduce the spread of drug-resistant superbugs.
UV-C is not available naturally on earth because it gets absorbed by the earth’s atmosphere and ozone. The human-made sources are used for Air and Surface applications. The effectiveness of sterilization depends on the total energy applied – dosage, which is affected by the exposure time and distance of the light source. E.g., A UV lamp takes 1-2 minutes to thoroughly sterilize an E.coli surface when placed at a distance of 1 inch. It takes 5-10 minutes to sterilize surgical instruments in a medium-sized UV box, and 30 minutes of exposure time is adequate in disinfecting an eight-foot biosafety cabinet in the lab.
In static applications, we can expose UV rays as long as needed to deliver an effective UV does to microbes. In cases where the exposure time is short, the UV intensity should be increased to be effective. Higher UV intensity is needed when the organisms are protected by particles such as dirt, dust, or biofilm as UV only works in its light path. It is essential to make sure the surfaces you want to sterilize are directly in line with UV light. This problem can be solved by using multiple UV bulbs and generating UV lights from different angles in which Aluminium is useful thanks to its high UV light reflectivity.
With the advancement in technology, small-sized, long-lasting UV emitting bulbs are available. Portable UV sanitizing devices are said to kill 99% of disease-causing bacteria, viruses and are used to disinfect water, air, fruits, veggies, surgical utensils, toys, and other contaminated surfaces. UV-C exposure can be dangerous. So it is advisable to use protective shields and avoid direct exposure to UVC, especially skin and eyes.