Ultraviolet light was discovered in the late 19th century. There are several types of UV. UV-A and UV-B occur naturally from the sun's rays. AirSteril technology generates UV-C otherwise known as ultraviolet germicidal irradiation (UVGI). UVGI is effective in destroying the nucleic acids in microorganisms so that their DNA is disrupted by the UV radiation, leaving them unable to perform vital cellular functions. This was first used commercially in the USA in the 1920's to control TB outbreaks, but fell out of favour when antibiotics developed mainly because direct exposure to UV-C can be harmful and its use is subject to regulation. However, the effectiveness of antibiotics is being challenged by resistant pathogens so the interest in the use of UVGI has recently increased.
An AirSteril air purifier utilises dual lamp ultraviolet light operating at the peak UVC wavelengths, creating germicidal irradiation, hydroxyl radicals, superoxide ions, plasma quatro and optional Ozone. This process freshens the air by killing airborne pathogens, viruses, bacteria, fungi, mould spores, dust mites, allergens and by decomposing odours and harmful gases.
An AirSteril unit uses five independent mechanisms. Each mechanism can be individually controlled to create tailor-made solutions to meet specific air purification requirements.
The five technologies are:
- Germicidal irradiation (UV light)
- Heterogeneous catalysis
- Triatomic oxygen sterilization (ozone)
- Plasma quatro
- Super oxide ion generation
In September 2009, the Health Protection Agency's laboratories at Porton Down performed efficacy testing of the AirSteril MP20 unit's ability to reduce aerosol and surface microbial contamination. Tests showed a reduction of airborne microorganisms of up to 98.11% within five minutes of exposure and a reduction of surface contamination up to 59.47% in one hour, the surface tests included MRSA. The full HPA report is available free of charge on request.