What is Ultraviolet Light (UV)?
Ultraviolet light is invisible to the human eye. It is part of the electromagnetic spectrum that lies beyond the purple range of the visible spectrum. The ultraviolet (or UV) spectrum has wavelengths between 100 and 400 nanometers (nm). The UV spectrum is further divided into wavelength ranges named UVA, UVB, UVC:
- UVA: sun tanning, testing, inspection, insect traps, stage effects, blacklight, phototherapy* (315-400nm)
- UVB: sun burning, inspection, analysis, testing, phototherapy* (280-360nm)
- UVC: germicidal (253.7nm), ozone producing (185nm)
*Phototherapy for treatment of skin diseases uses bulbs emitting in the UVA and UVB spectral range. There is also non-UV phototherapy for treatment of infant jaundice. These bulbs, "bili lights", are low or non-UV emitting fluorescent or halogen sources with strong blue light in the visible spectral range of 425-475nm.
Warning: UV radiation is harmful to skin and eyes.
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What are the Different Types
of Ultraviolet Bulbs?
UV-A Blacklight Bulbs
Low-Pressure Mercury Arc Lamps
UVA wavelength range: 315nm - 400nm
Peak: 352nm
Used for: photosensitization and photochemical reaction applications and insect traps. Output includes visible light.
UV-A Blacklight Blue Bulbs
Low-Pressure Mercury Arc Lamps
UVA wavelength range: 315nm - 400nm
Peak: 352nm or 368nm
Used for: tests, inspections, examinations, stage illumination. Deep blue filter glass absorbs visible light, transmits near UV.
UV-B Bulbs
Low-Pressure Mercury Arc Lamps
UVB wavelength range: 280nm - 360nm
Peak: 306nm
Used for: inspection, analysis, testing (UV resistance of paints, plastics, rubbers), dermatology phototherapy
UV-C Germicidal & Ozone Bulbs
Low-Pressure Mercury Arc Lamps
Germicidal Peak: 253.7nm
Germicidal plus Ozone Peaks: 253.7nm and 185nm
Used for: sterilization of surfaces, materials, air and water
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| Introduction of UV |
| There are no micro-organisms known to be resistant to UV, unlike chlorination. UV is known to be highly effective against bacteria, viruses, algae, molds and yeasts, and disease causing oocysts like cryptosporidium and giardia. In practice, bacteria and viruses are the cause of most major waterborne pathogenic diseases. Of these enteric viruses, hepatitis virus and Legionella pneumophila have been shown to survive for considerable periods in the presence of chlorine, but are readily eliminated by UV treatment. For most microorganisms, the removal efficiency of UV for microbiological contaminants such as bacteria and virus generally exceeds 99.99%. Specifically, the following are moved to an efficiency of greater than 99.99%: E-coli, Salmonella typhl (Typhoid fever), Salmonella enteritidis (Gastroenteritis), Vibrio cholerae (Cholera), Mycobacetrium Tuberculosis (Tuberculosis), Legionella pneumophila (Legionnaires' Disease), Influenza Virus, Polio virus, and Hepatitus A Virus (better than 90%). |
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| Introduction of UV |
| There are no micro-organisms known to be resistant to UV, unlike chlorination. UV is known to be highly effective against bacteria, viruses, algae, molds and yeasts, and disease causing oocysts like cryptosporidium and giardia. In practice, bacteria and viruses are the cause of most major waterborne pathogenic diseases. Of these enteric viruses, hepatitis virus and Legionella pneumophila have been shown to survive for considerable periods in the presence of chlorine, but are readily eliminated by UV treatment. For most microorganisms, the removal efficiency of UV for microbiological contaminants such as bacteria and virus generally exceeds 99.99%. Specifically, the following are moved to an efficiency of greater than 99.99%: E-coli, Salmonella typhl (Typhoid fever), Salmonella enteritidis (Gastroenteritis), Vibrio cholerae (Cholera), Mycobacetrium Tuberculosis (Tuberculosis), Legionella pneumophila (Legionnaires' Disease), Influenza Virus, Polio virus, and Hepatitus A Virus (better than 90%). |
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