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How UV Light is Used in Air Purification

When you think about air purification, most think of HEPA filter based media. This is no coincidence, as these air filters are the foundation of quality air cleaning and still the gold standard for air purifiers. 

High efficiency air filters and a strong motor are the most effective technology in catching airborne viruses and removing them from the air that you breathe resulting in mitigating viruses being spread.

But there are other technologies that can be used for many different air cleaning purposes. UV Light only air purifiers, in comparison to air purifiers that also have HEPA filter based media, typically target and sterilize mold and mildew growth within 15-30 minutes of exposure to be truly effective.

UV-C light, one of three types of ultraviolet light, is commonly used in air purification. When properly utilized and given enough exposure, this invisible form of light can safely target and kill mold and mildew.

So, what is UV-C light, and how can purifiers safely use this technology to purify the air?

Let’s find out...

What is UV Light?

You’ll hear about it all through the summer. It’s ultraviolet light, and it’s a big enemy of swimmers, beach-goers, and sun lovers everywhere.

But what is it?

UV light, like radio waves and X-rays, is an invisible form of electromagnetic radiation.

It causes sunburns by destroying cells, and this cell-destroying ability is what makes it effective for destroying air impurities, specifically mold and mildew.

Ultraviolet light is a form of light that rests just outside the visible spectrum for humans. The wavelength of UV light is shorter than visible light, but longer than X-rays. It’s estimated that UV light makes up about 10% of the sun’s output.

Of course, UV light is also created artificially, by technologies that include arc welders, tanning beds, black lights, and some forms of air purifiers.

UV Light: The ABC’s

UV light is a part of the light spectrum, a part of it that we can’t see, but can certainly feel after a full day in the sun.

However, UV light is actually divided into three different subcategories.

UV-A: The Most Common

UV-A accounts for 95% of the sun’s radiation that reaches the earth. It is the type of light used in tanning beds but also causes skin wrinkles and premature aging.

UV-B: The Biggest Concern

The second type is UV-B, and this is largely the type that causes the most sunburns. It affects the top layer of your skin and damages DNA. UV-B is strongly linked to skin cancer.

UV-C: The Most Harmful

The bad news is that UV-C light is the most dangerous to living organisms and cells. The good news is that the earth’s atmosphere blocks 100% of UV-C radiation from the sun.

However, UV-C can be made artificially. When used properly, the harmful nature of UV-C can be harnessed to purify air. That’s right: the most harmful type of UV light is actually our ally in air purification.

So, while UV light (specially A and B) from the sun harms our skin, it’s actually a different but closely-related type that is used to clean the air.

How UV Light Purifies Air

So, how can UV-C light, a natural product of the sun, help purify indoor air?

It all has to do with the UV-C light’s ability to destroy cells. UV light harms cells by destroying nucleic acids and disrupting their DNA, which either kills them or leaves them incapacitated. After prolonged exposure to UV light, cells are unable to perform their vital functions.

With an air purifier with UV-light technology, air is pulled into the appliance and passes through a fine high efficiency air filter. The air then passes through a small internal chamber where it is exposed to UV light.

The key here, though, is prolonged exposure. UV-C light needs direct and prolonged exposure to be effective and doesn't work well as the main cleaning method.

That's why we rely on the scientifically proven method of pleated HEPA filter based media filtration in an air purifier as a main defense and only ever use UV as a supplement to it. Because UV light needs prolonged exposure to clean contaminants in the air, and air purifiers are designed to move air quickly to properly clean and ventilate a room, it can render the UV-C light less effective than a mechanical form of filtration. 

UV can be harmful if you look at the light, so it must be contained to be in an air purifier. The UV-C light is not released into the room, so you won’t see it nor will you be exposed to it. Depending on the model, the air will then go through another filter before being released into the room.

The Best Uses for UV Light

Various air purifiers serve different purposes and achieve different goals.

While many are versatile, removing multiple types of contaminants, some are specialized for dust, pollen, pet dander, viruses, or even odors.

So, what about UV light?

Because UV light is effective in killing cells, it is therefore effective at eliminating living airborne organisms. Namely, mold and mildew.

Mold reproduces through spores that are released into the air, much like pollen from a flower. The mold spores float in the air and eventually land in places where they can grow into new mold.

With the use of germicidal UV-C light in air purifiers, you not only trap mold spores, you effectively destroy them, keeping the spores from forming new mold.

UV light is effective at destroying airborne contaminants such as mold spores, but if mold has already taken hold, it will need to be cleaned by direct methods.

Air purifiers can only eliminate the spores floating through the air, they can’t do anything about the mold hiding in walls or underneath carpet.

Another use for UV light is the elimination of viruses and bacteria. While more research and development is needed, UV light, when properly utilized and given direct, prolonged exposure to the contaminants, has been shown to reduce the amount of viruses and bacteria in the air.

UV light will sterilize viruses and bacteria faster, but a  high efficiency air filter and a strong motor will filter out airborne viruses and they will naturally die on their own. It's most important to have a high-grade filter and strong air flow in a purifier because achieving the contact time UV light needs to be truly effective is difficult when pushing all of your air through the purifier.

UV Light Air Purification Compared to Other Methods

So how does UV light compare to other methods? Let’s look at a few of the most common strategies and technologies that are used in air purification to discover how UV light compares.


Many room air purifiers use filters to trap particles in the air. This strategy, which includes advanced HEPA filter based media, is extremely effective for removing large particles, such pollen or pet dander, but may struggle with extremely small particles, depending on the filter efficiency.

However, a filter alone does not kill germs and mold spores quickly, it traps them and they die on their own. A combination of a real  high efficiency air filter and UV light works as the filter catches particles and gives the light enough time to completely sterilize and kill the harmful particles. Just a UV light on its own is not as efficient because the particles need to be captured in the air purifier for the UV light exposure to have enough time to succeed in effectively killing the harmful particles.

Activated Carbon

This is an advanced type of filter that uses highly-porous charcoal to trap gases like odors or smoke. Because of all the pores, activated charcoal has a massive surface space, which can be utilized to hold large amounts of gases. While a key technology in smoke removal, it does not sanitize or destroy germs or other living organisms. 

Electrostatic Precipitators

This type of purification is used extensively to clean industrial fumes, steam, and gas before it is released into the atmosphere. Essentially, it creates static cling which traps particles, but the process creates a small by-product of ozone, which is harmful to health, making contained UV-C light a safer alternative.

Ozone Generators

Ozone generators are used to “shock” a room with ozone, a harmful substance that must be used with extreme caution. While ozone generators can be used for mold remediation and odor removal, they should generally be used only by trained professionals operating under meticulous safety procedures. 

Oransi has industry-leading air purifiers that can be used to reduce mold spores, pollen, dust, and odors. If you need help choosing the right air purifier, please contact us today; we would be happy to help you choose the right product for your specific needs.

From bedrooms to commercial offices, we have the right air purifiers to create a healthy space for everyone!