The Effect of UV Light on Microorganisms
Ultraviolet (UV) light is part of the electromagnetic spectrum beyond that provided by the sun and other sources that humans typically can see. Today's society uses UV light as a disinfectant and to study the structure of atoms. Radio waves, microwaves and X-ray machines are also part of the electromagnetic spectrum.
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Ultraviolet Light
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Ultraviolet light consists of four different types: UV-V, UV-A, UV-B and UV-C. The light emitting from black light fixtures are UV-A, while the rays that cause sunburn are UV-B. UV-C light rays are germicidal (which can kill microbes), and UV-V produces ozone in the atmosphere.
UV-C Rays
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UV-C light can penetrate the outer cell membranes of microorganisms such as viruses, bacteria, mold and mildew. The UV-C modifies the DNA, forcing it to replicate incorrectly and subsequently causing the death of the microorganism.
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Effect on Haemophilus Influenzae
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In a study that appeared in the July 1970 "Journal of Bacteriology," low quantities of UV light temporarily blocked cell division in UV-resistant haemophilus influenzae. The rate of DNA synthesis was also slowed under small amounts of UV light.
UV Lamps
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There are germicidal lamps that emit a powerful and concentrated source of UV-C light. The UV light destroys airborne microbes such as tuberculosis, flu and cold viruses, and even smallpox. Germicidal lamps also eradicate many airborne allergens, such as molds, mildew and fungi.
UV Disinfection
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Disinfection of water in the U.S. has been done by UV light since 1916. Similar to the process used by UV lamps for airborne microbes, the water is exposed to UV radiation to render any microorganisms harmless.
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References
Resources
- Photo Credit Image by Flickr.com, courtesy of Steve Jurvetson
