February 25, 2016
February 22, 2016
Ultraviolet Light (UV-C) - No other purification method is more popular at killing Germs and Viruses
We purify drinking water, yet only ingest up to 5lbs of liquid a day. Meanwhile, each person takes 20,000 breathes a day resulting in an intake of 36 lbs of air a day. So why are there laws to ensure we purify our drinking water, yet there are no laws for air purification, and few people purify their indoor air?
History of UV Light and Sterilization Ultraviolet (UV) Light has been a known to be effective at destroying germs, viruses and other the DNA of other harmful contaminants for more than 100 years. In 1878, Arthur Downes and Thomas P. Blunt published a paper describing the sterilization of bacteria exposed to short-wavelength light (UV). In 1903, the Nobel Prize for Medicine was awarded to Niels Finsen for his use of UV against lupus vulgaris, and tuberculosis of the skin.
Filtration and the Role of UV Light Ultraviolet light (UV) possesses just the right amount of energy to break organic molecular bonds. As micro-organisms pass by the UV rays emitted from an ultraviolet lamp, the DNA bonds are broken which results in enough cellular damage to inhibit micro-organisms from harming people. UV light is able to destroy the DNA of germs, viruses, bacteria, fungi, molds and many other harmful pollutants. There are different wavelengths of UV light. The shortest wavelength is UV-C which is considered "germicidal UV".
UV Light and Water Purification UV light has been used to disinfect drinking water dating back to 1910 in Marseille, France. By 2016, countries all over the world have developed regulations that allow municipal water systems to disinfect their drinking water supplies with UV light. For example, there are over 6,000 UV commercial water treatment plants operating in Europe, and even more in North America.
Personal residences that are “off the grid” like cottages, ranches, cabins and island homes also use UV water purification systems. Residential UV systems have seen significant changes over the past 15 years. Not only to the systems and the technology, but to the laws, regulations, and certifications that now apply to residential UV systems. Many jurisdictions
now require NSF Standard 55 Class A UV systems to be installed in all places where the public may get water. The province of Ontario in Canada was one of the early jurisdictions to pass UV regulation as part of the Safe Drinking Water Act (2002). Since then, jurisdictions in the USA like Ohio, New York and many others began to adopt UV as the chosen technology for applications where disinfection of drinking water is needed.
UV Light and Medical Sterilization Many medical instruments are sterilized using germicidal UV lamps. Medical and Dental instruments are inserted into a machine that contains a germicidal UV lamp, and exposed to intense UV light that is 20,000 times stronger than the UV beams emitted from the sun. The UV light kills any residual viruses, bacteria, fungi, or other harmful micro-organisms. Even medical garments, such as hospital gowns and doctors' scrubs can be sterilized using germicidal UV lamps.
UV Light and Indoor Air Filtration More recently, UV lights have been used to ‘clean’ indoor air of harmful pollutants. Indoor air purification systems use a fan to pass air by the UV lights. Key to this form of sterilization is placement of the UV lights, and a good filtration system to remove the dead microorganisms. For an indoor air purifier to be most effective, the passing air should flow by UV-C bulbs in a parallel flow to maximize the exposure times with no shadows or obstructions between the lights and the airflow.
UV-C Technology in Surgically Clean Air Purifiers
All Surgically Clean Air Purifiers use UV-C light bulbs in their 5th stage of filtration within the kill chamber. Each purifier has been designed to maximize the exposure of the air flow to the UV-C bulbs in three ways: (i) the airflow goes parallel to the light bulbs, (ii) the UV-C chamber is an open space with no obstacles that can block the light from striking the air flow, and (iii) there are two UV-C bulbs to fully illuminate the kill chamber.