La lumière UV de type C fait partie des trois types de lumières ultraviolettes émises par le soleil. Invisible à l’œil nu, elle fait partie du spectre électromagnétique émis par notre soleil et sa longueur d’onde est comprise entre 400 nm (750 THz) et 100 nm (30 PHz).
Le rayonnement UVC est exploité par la lampe UV des purificateurs d’air, notamment pour ses capacités de stérilisation et de purification de l’air.
What are the different types of ultraviolet radiation?
Ultraviolet rays include :
- UV type A radiation They represent 95 % of the sun's UV radiation. These rays can penetrate deep into the layers of our epidermis. They cause the appearance of wrinkles and the ageing of the skin.
- UV type B radiation UV radiation: this UV radiation is mostly filtered by the atmosphere. They penetrate less deeply into the skin than UV-A. However, they are still dangerous, as they promote skin ageing and the appearance of skin cancers.
- UV type C radiation These rays are dangerous for all forms of life. Completely blocked by the ozone layer, they are capable of damaging DNA and RNA. These rays are very effective in inactivate viruses and bacteria.
What is the purpose of the UV lamp in an air purifier?
The UV lamp is used in air cleaners to kill germs, mould spores, bacteria and even viruses. This air disinfection system is found in high-end and mid-range devices. This technology can be used on its own, but it is not able to capture airborne particles. It is therefore always combined with a HEPA air filter to ensure quality air filtration.
In air purifiers, the UV lamp (with a wavelength of only 256 nm) is able to effectively kill micro-organisms, such as germs, bacteria and viruses. By destroying the cells, the UVC lamp sterilises micro-organisms. However, it only alters their DNA, it does not remove them from the air.
To remove allergens such as dust particles, dust mites, pollen or pet dander, the air purifier should also be equipped with a HEPA quality filter. This filter can be supplemented by an activated carbon filter for odour treatment.
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Is UV light harmful to humans?
Although many brands of air purifiers have stated that the UV lamp is completely harmless to humans, we think you should be aware of the nature of its light. The intensity of UV light decreases dramatically with distance, so the further away you are from the UV light source, the less exposure you have. In addition, the absorption length of UVC rays in human skin is very short, so they cannot reach living cells.
Normally, UVC is not harmful to humans. And most importantly, the UV lamp bulb is completely hidden inside the air purifier, so there is no chance that you will be exposed to ultraviolet light.
Just like the plasma technologyThe UV lamp is able to emit a certain amount ofozone. Ozone is a gas that is harmful to your health, as it causes serious respiratory problems. If you are using an air purifier with a UV lamp and you experience side effects on your health (breathing difficulties, lung irritation, etc.), you should switch it off as soon as possible and dispose of it.
To find out which air purifier is certified by the California Air Resources Board (CARB), see the California Certified Air Cleaning Devices. It should be noted that the Californian (USA) regulations are the strictest known to date on standards related to indoor air purification. The devices listed and validated by this organization (with or without UV lamp) are synonymous with quality and can therefore be used safely.
It should be noted that UVC air filtration and associated standards are likely to evolve in the near future in France. In order to better protect the population, some countries such as Belgium have already started to legislate on the marketing of air purifiers. The aim is to ensure better control of the supply, as many shops offer inadequate or even dangerous systems, depending on the technology used (because they emit ozone).