Light is made up of tiny discrete amount of particles or quantum of electromagnetic radiation called photons. Photons will transmit a high level of electromagnetic energy when they encounter matter. As the light travel, they will send vibration back and forth creating a trace of light wavelength. The shorter the wavelength, the quicker the vibration thus the higher the energy released. Different forms of light have different wavelengths and different energy levels. Ultraviolet light has a short wavelength between 100 to 400 nanometers. Visible light has a wavelength between 400-700 nanometers. Infrared light has a longer wavelength between 700 nanometers to 1 millimeter.
What Is Ultraviolet Light?
Ultraviolet light is a type of invisible electromagnetic radiation with a wavelength from 10 nm to 400 nm. As part of the sunlight spectrum, UV light is shorter than visible light but longer than X-rays. UV radiation contributes about 10% of the total sun’s output. Historically, ultraviolet light is only used to disinfect water and surfaces. Now, you can find UV in black light (backdrop), tanning beds, arc welder, bottle sterilizer, medical equipment, and air cleaner.
How Does UV light Clean Air?
UV light works as how natural sunlight would. Disrupt microorganisms DNA cell thus killing or inactivate them from functioning. With the nucleic acids destroyed, microbes that are exposed to the UV-light would be left incapacitated. Most UV light bulb is made with phosphor or quartz materials. The emitted light may be invisible to us or with a slight blueish tint. With continuous application, UV light bulb efficiency will degrade over time. Most UV light bulb has a lifespan of 5,000-10,000 hours that requires replacing on a yearly basis. The durability of the lamp, temperature. humidity and design will also have an impact on UV performance.
What is UV air purifiers?
UV air purifiers are a single technology, stand-alone device used to clean the indoor air. When air is pulled into the devices, it will pass through a small internal chamber exposing to UV light. Through the sole power of ultraviolet light, the air cleaner will kill off microorganisms like mold, bacteria, and viruses. It is poor against pollutants like dust, smoke, and odor due to the lack of mechanical filter. Most UV air cleaners are compact and slim because there is only one filtration and it uses a thin light-bulb.
As for HEPA air purifier with UV light, it uses multiple filtrations to purify the air. When air is pulled into the filtration, the initial pre-filter, HEPA filter or carbon filter will trap all bypassing particles. This includes dust mites, pet dander, mold, pollen, tobacco smoke, bacteria, and viruses. The UV-light will then proceed by eliminating all trapped microbes on the filter so only clean air will be released out. HEPA air purifier with UV light is much more effective than a single UV purifier because it covers a wide array of pollutants.
Ultraviolet Light: UV-A, UV-B and UV-C
The shorter bands UV light has, the stronger energetic UV radiation will be produced by the Sun. Generally, Ultraviolet light is subdivided into 3 categories:
- UV-A – The least dangerous ultraviolet light here. Long-wavelength 315–400 nanometers photons that vibrate the slowest. It is closest to surface area and covers around 95% of the sun’s radiation. Commonly used in tanning booths or disinfection tools. Overexposed to UV-A can cause the skin to wrinkles and age quicker.
- UV-B – Medium-wavelength, 280–315 nanometers photons that vibrate slightly faster. It is often used in plant development to alter plant hormones. Overexposed to UV-B ray can cause skin cancer and damage your DNA. Good news is about 95% of the UV-B light is absorbed by Earth’s atmosphere.
- UV-C – The most harmful UV light to living organisms and cells. Short-wavelength, 100–280 nanometers photons that vibrate the fastest. Prolonged exposure to UV-C light can cause permanent damage to DNA, eye, and skin cancer. Fortunately, 100% of UV-C radiation will be absorbed by Earth’s ozone layer. UV-C light is commonly used in sterilizing devices to clean and disinfect germs. All air purifier with UV light would be using type C as it is the most effective in killing bacteria and viruses.
Is UV C Light Safe In Air Purifier?
UV technology existed since 1908 and it is proven to be safe and reliable. There are reports suggested that UV-C radiation from an air purifier can be transfer out through oxygen in the air if the UV-lamp is uncoated. Through photolysis, the oxygen is broken apart and combine with other oxygen molecules to create ozone.
Exposing to UV-C lamp can cause sunburn and damage your eyes. In long-run, it can cause skin cancer, destroy your DNA and skin cell resulting irreversible damage. To prevent being directly exposed to UV-C lamp, avoid staring at the UV-light when it is active. Also, make sure the UV-light is properly installed in an air purifier with the cover closed.
What Is The Best Air Purifier with UV light?
There are many types of air purifiers with UV light in the market designed for different target audiences. It may be the devices main purification or as a subsidiary to its other filtration. So what we are looking for its the overall strength of an air purifier in dealing with all kinds of airborne pollutants. This includes dust, mold, pollen, mildew, spore, pet dander, bacteria, smoke, and viruses. Here is our best pick.
- Winix HR900
- PureZone 3-in-1
- Rabbit Air BioGS
- GermGuardian AC5250PT
- GermGuardian AC4100
- GermGuardian AC9200WCA
Whether is HEPA filter, carbon filter, Ionizer or UV-light, the air purifier filtration must be at the top of its game. To learn more, go to our best air purifier for germs with UV light page.