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UV-Light Air Purifiers: What Are They And How Do They Work?

If you’re looking for a way to improve the air quality of your home, you might be wondering if a UV air purifier would be effective and a worthwhile investment. Before you decide to jump in and purchase a UV air purifier, let’s dive in and to learn more about this method of air purification and to determine whether or not it would be worthwhile investment.

What is A UV Light Air Purifier?

As mentioned above, UV air purifiers use short-wave ultraviolet light (UV-C light) to kill pathogens and microorganisms that float through the air; viruses, mold, and bacteria, for example. The goal of a UV air purifier is the same as any other type of air purifier: minimizing the level of airborne pollutants. This type of air purification technology is also known as “UV germicidal irradiation” or “UGVI air purifiers”.

UV-C air purifiers are made as stand-alone or free-standing units, or they can be specialized systems that are installed into heating, ventilation, and air conditioning (HVAC) systems. No matter the type, the manner in which a UV air purifier works is pretty simple. As air enters the system, it makes its way past UV lamps, and the UV light the lamps emit try to disinfect the air via germicidal irradiation. Though it is effective, there is a safety concern to be aware of: there is a chance that ozone could be made and emitted during the disinfectant process.

UV-C light air purifiers very rarely function as stand-alone devices; rather, they usually need an additional system in order to reach their full effectiveness. The vast majority are incorporated in large-scale High-Efficiency Particulate Arrestance (HEPA) air filtration systems. According to the United States Environmental Protection Agency (EPA), UV-C air purifier is very rarely effective when used as a stand-alone device, as it is unable to remove or collect airborne particles.

A Brief History of Ultraviolet Light Purification

Ultraviolet (UV) light has long been used as a form of disinfectant for various elements, including surfaces, food, water, and the air. This disinfectant method mimics the natural UV light that the sun generates. In short, it involves utilizing short-wavelength ultraviolet light to breakdown and destroy nucleic acids and thus, disrupting the DNA they contain, rendering them unable to complete essential cellular functions, thereby inactivating or killing microorganisms.

The use of germicidal UV light for disinfectant purposes originated in the middle part of the 20th century, and initially, it was used for medical sanitization and in workplace facilities that require sterile environments; for example, it was commonly used as a way to treat tuberculosis, meat processing plants, and laboratories. Due to the success in these applications, UV light began being used to sterilize both drinking and wastewater. In fact, UV light was used as a way to disinfect municipal water in France as far back as 1908.

An Overview of Different Types of Light

Ultraviolet light, visible light, and radio waves; there are many different forms of electromagnetic light. In order to understand how UV light is used for purification, it’s important to understand how light works.

Light is comprised of minuscule particles known as photons. As those particles travel through the air, they create vibrations and as they do, the trace waves in space. The faster photons vibrate, the shorter the distance is between each wave, and the slower the vibration, the longer the distance between each wave. The distance between waves is known as “wavelength”. The photons in long waves vibrate slower, and therefore, have lower energy levels, while the photons in short waves have higher energy levels.

The manner in which materials reflect and absorb wavelengths of light varies and depends on the molecular makeup of the material. Examples include:

  • The wavelength of visible light ranges from 400 to 700 nanometers long; the range that impacts your eye’s light receptors.
  • The wavelength of infrared light range from 700 to 1 million nanometers, the light that you feel as heat.
  • The wavelength of ultraviolet light, which you can’t see or feel, is much shorter; about 100 to 400 nanometers.

Photons, those tiny particles that light contains, transmit electromagnetic energy when they come into contact with matter. The amount of energy that ultraviolet (UV) light has is quite high, and there are three different types of UV light, which include:

  • UV-A. The wavelength of this type of UV light ranges from 315 to 400 nanometers and the photons vibrate slightly faster than visible light, and therefore carry the lowest amount of energy.
  • UV-B. The wavelength of this type of UV light ranges from 280 to 315 nanometers, with photons that vibrate an even higher rate, and therefore, carry a medium amount of energy.
  • UV-C. The wavelength of this type of UV light ranges from 100 to 280 nanometers, and the photons in UV-C light vibrates the fastest, and therefore, carries the highest amount of energy.

Because UV-C light carries very high energy levels, prolonged exposure can damage the skin and eyes, and as such, safety precautions should be taken when working directly with or within close proximity to lamps that emit UVC light. In regard to disinfection, UV light is used as a way to accent other disinfectant and sterilization methods; for example, it can be used to sanitize medical equipment and facilities, in conjunction with other types of sanitization methods. In recent years, UV light has been used in a new application: as a way to purify indoor air. Equipment that uses UV light to purify air reduces the level of airborne pollutants, thereby improving the cleanliness of the air; it does not eliminate infectious particles from the air.

How is UV-C Light Used in UV Light Air Purification Systems?

The primary activity used in UV-C air purification systems, as you can probably guess, is UV-C light. As noted above, of the three different types of UV light, UV-C has the shortest wavelengths, and thus, the highest energy level. That high degree of energy can modify the molecules (the materials) that absorb UV-C light. The DNA the molecules contain is highly susceptible to modifications. UV-C light overruns the microorganisms that surround the lamp that is generating it, and as such, effectively damaged the DNA that those microorganisms need in order to survive.

An easy to understand example of how UV light can damage microorganisms is sunburn. If you’ve ever gotten a sunburn, what you’re actually suffering from is radiation burns as a result of the type of UV light the sun emits. The DNA within your skin cells is damaged by the sun’s UV radiation, and the redness you develop is the result of your skin’s inflammatory response to that damage.

Because bacteria are single-celled, they need DNA in order to survive. This is the basic principle of how UV light purifiers work. When the DNS of a bacteria’s cell is damaged enough, a self-destructive mechanism is activated within that bacteria, and thus, it becomes harmless. There are several UV-C air purifier applications. One scientific study examined germicidal UV lamp placement on the walls of a healthcare setting, and it was found that the UV lamps showed no statistically significant side effects as a result of excessive exposure to UV light. These finding reinforce the benefits of using UV light purification in healthcare settings.

How is the Air Cleaned by a UV-C Air Purifier?

The manner in which UV-C light air purifiers work is actually pretty straightforward. As previously mentioned, these air purifiers are specially manufactured to utilize lamps that emit UV-C light that could possibly chance the DNA that microorganisms contain, and as a result, destroy those microorganisms. The color of the light that the air purifier emits depends on the type of emitter it contains; for example, the light may have a blueish hue, or it may not emit visible light that the human eye can actually see. Typically, UV air purifiers that are designed for residential use contain mercury lamps, and the wavelength of the UV-C light that the lamps emit is about 254 nanometers, as per the US Environmental Protection Agency (EPA).

Also as previously mentioned, UV light air purifiers are usually used to complement other types of air filtration systems; a HEPA filter, for example. In this example, the UV light that the air purifier emits acts in unison with the HEPA filter to purify the air. Ambient indoor air is pushed through the system and is ventilated back out through a chamber that features light bulbs that emit UV-C frequency light. There are several factors that will impact the efficacy and performance of this kind of UV lamp, such as temperature and humidity levels.

The UV-C lamps that UV-C germicidal air purifiers contain are typically whisper-quiet, and usually, the light that is emitted is not visible to the human eye. Usually, they are odorless, too. On average, the UV bulbs will need to be replaced once a year, depending on the manufacturer and the level of use.

Are UV Air Purifiers Dangerous?

Just like any other product, before you start using it, you want to be sure that it’s safe. Given the fact that air is vital to your overall health, well-being, and very survival, ensuring that anything that will impact the quality of your indoor air is safe is essential. With that said, are UV air purifiers safe? There is one concern, and it’s important to note: the UV-C radiation that these purifiers emit have been found to change oxygen atoms that air is comprised of into ozone. This transformation occurs as a result of a process known as photolysis, a process that causes oxygen to split apart into two separate atoms and then combine with other oxygen molecules, creating ozone. There’s a greater chance that photolysis occurs when uncoated UV-C lamps are used in a UV air purifier. In order to reduce the risk of ozone development, some manufacturers of UV air purifiers use UV lamps that are equipped with a specialized coating.

Are UV Air Purifiers Effective?

While UV-C light does have the potential to breakdown microbes, whether or not a portable air purifier that is outfitted with UV-C emitting light bulbs is subject to question. Manufacturers of these air purifiers advertise that they can effectively reduce the presence of allergens in the air, including mold spores and dust mites. While they may be able to do so, it’s important to note that the effectiveness of portable UV-C light air purifiers depends on several factors, including:

  • If the airborne pollutants actually come into contact with the UV light the air purifier emits
  • Whether or not the UV light is inhibited by the cooling effect of the flow of air
  • The material that the bulb emitting UV-C light is made of
  • The dosage of light that is needed
  • The length of time the target pollutant is exposed to  the UV-C light

Schedule a Mold Inspection with A Reputable Professional

If you suspect mold is growing in your home and you’re thinking about investing in a UV light air purifier as a means of improving your indoor air quality, the air purifier might provide some benefit; however, it will not correct the problem. Rather, a UV light air purifier will only mask the problem; if at all. In other words, a UV air purifier may or may not remove airborne mold spores from your indoor air. Therefore, if you really want to improve your home’s indoor air quality, the best solution is confirm whether or not mold growth is actually to blame, and if it is, taking the measures that are necessary in order to eliminate the mold.

If you’re interested in scheduling an appointment for a mold inspection, contact one of the most trusted companies in the country: Mold Inspection and Testing. With years of experience, a proven track record of excellence, and locations throughout the country, our technicians can successfully identify whether or not mold growth is, in fact, a problem in your home so that you can get to the rood of the problem and actually improve the health and safety of your home.