UV light air purifiers are those purifiers that use short-wave ultraviolet light or UV-C light so as to disable the microorganisms like bacteria, viruses, mold, and fungi, along with pathogens that are airborne. This technology is similar to UVGI air purifiers or UV Germicidal Irradiation as the primary motive is to eliminate pollutants that infect the indoor environment. However, UV light Air purifiers use technology different from conventional air purifiers that use UV radiation indirectly against air contamination.
How Do UV Air Purifiers Work?
They are available as stand-alone clean air devices or devices installed in the systems already fitted into commercial or residential HVAC units in the market. Proper air filtration is effective against the microbes already present in the HVAC units. Here, the air is passed through the device where it travels through UV lamps.
These UV lamps are responsible for killing the microorganisms, thereby disinfecting the air by germicidal irradiation. In the process, ozone may be produced that might affect the health of the individuals. In the case of stand-alone air purifiers, supplementary systems are required to produce effective results. These clean air devices are inserted in more enormous, High-efficiency Particulate Arrestance (HEPA) air filtration systems for that to happen.
But as per Environmental Protection Agency (EPA), stand-alone air purifier devices are not as effective as the pre-installed versions because these lack the ability to trap abolish particles altogether. In another study, it was found that when germicidal UV lamps were placed on the walls of healthcare dwellings, they performed disinfection without any side effects of overexposure.
What is the history of UV light?
Since time immemorial, UV light has been extensively used to disinfect hospitals, chemical laboratories, meatpacking industries, etc. It was also used to treat diseases like tuberculosis and disinfection of water bodies in France in 1908. UV light has a wavelength between 100 to 400 nanometers, and photons transmitted through it have high energy levels. UV light is divided into three categories -
1) UV-A having a wavelength between 315 to 400 nanometers
2) UV-B having a wavelength between 280 to 315 nanometers
3) UV-C having a wavelength between 100 to 280 nanometers
Out of all these, UV-C has photons that vibrate at a faster rate and produces more energy, followed by UV-B and then UV-A.
Because of the ability of UV to sterilize any material that falls under it, it has been used for disinfection purposes for a very long time for residential and commercial purposes. But on the other hand, prolonged exposure to UV light can cause skin damage and even cause temporary eye loss.
What Can UV Air purifiers collect/clean?
UV Air cleaners clean all the pollutants that get accumulated indoors, causing harm to the health of the individuals. These purifiers produce UV light that removes microorganisms like bacteria, viruses, molds, and fungi. These collect all the toxicity produced in the environment and maintains clean and fresh air to breathe.
How do UV light air purifiers use UV-C light?
UV-C light in UV light air purifiers performs the disinfection process using the extra energy that has a range greater than visible light. This mechanism changes the molecule that is absorbed by it, and it affects the Deoxy Ribonucleic Acid (DNA), which is sensitive to all these changes. UV light kills the minute organisms present in the air and attacks their DNA. The example can also explain that when people spend some time on the beaches, then they experience radiation burns or, in simple terms sunburn, the next day. This happens due to the UV light produced by the sun, and the redness on the skin is the inflammatory response indicating the DNA being damaged under the direct UV light. Excessive UV light can harm the skin causing skin cancer. As bacteria are single-celled organisms, they rely on DNA to survive. If the bacteria's cell gets damaged to a greater extent, it exhibits self-destruction, becoming harmless. This is the main principle of a UV light air purifier.
How do UV air purifiers clean the air?
UV air purifiers implement UV lamps in changing the DNA of microorganisms. This, in turn, kills or disables the organisms, thereby cleaning the air in the process. The color of the light being emitted may be different depending upon the material of the emitter, like phosphor, quartz, and so on. The color may sometimes be blue or colorless, indicating that's it not in the visible range. In residential places, mercury lamps are widely used that emit UV-C light in the range of 254 nanometers as per Environmental Protection Agency (EPA).
These UV air purifiers combine forced air systems and filters like High-efficiency Particulate Arrestance (HEPA) filter systems. This helps UV light to act together with the plan to clean the air. Clean air is forced into the indoors, and ventilation occurs through chambers consisting of bulbs emitting light in the UV-C frequency. The UV lamp is placed in such a way that it is downstream of the filter in a portable air purifier. Other factors that are responsible for the cleaning process are UV lamps, humidity, and temperature. However, in the case of UV germicidal cleaners, the UV-C light is silent as it produces light invisible to the human eye and its glow depends on the casing that is mounted around it. It is also odorless, and the bulbs used need to be changed every year depending on the model, type, and company.
Dangers of UV air purifiers
Apart from skin cancer caused by excessive UV light, some other dangers are significant to note. UV-C radiation in the UV air purifiers changes the oxygen present in the air into ozone. This occurs because when photolysis occurs, light triggers the oxygen to break down into two separate atoms and attract other oxygen atom to form ozone. This is due to the uncoated UV-C lamps, and to overcome this, companies are using special coatings on lamps.
How effective are UV air purifiers?
UV air purifiers disable or kill microorganisms and reduce allergens and dust mites that are commonly found indoors. This functionality depends on various components like -
1) The amount of light required
2) The duration of the pollutant being exposed to light
3) Whether the UV light has come across the pollutants
4) The material of the light bulb emitter
5) Whether the colling effect of airflow impedes light
Usually, microbes are resistant to UV radiation, and to deactivate them, a higher range of light or radiation is required. As per Environmental Protection Agency (EPA), more prolonged exposure duration and a higher degree are needed to kill microbes effectively. Regarding other particles like allergens, clouds of dust, smoke, fumes, etc., UV light cannot eliminate these. Also, poisonous gases and minute solid particles are insusceptible to UV light. UV light cannot altogether disable mold particles, and because of this, skin allergies may occur in some individuals. Hence, it is not adequate for patients having asthma and allergies.
UV light is also ineffective to volatile compounds (VOCs) commonly encountered indoors in varnishes and solutions. Due to the enormous frequency of UV light, VOCs vaporize quickly into the air, transforming into poisonous gases.
UV or Not UV: What Is the Difference in Air Purifiers?
UV air purifiers use high-frequency UV lamps that kill or disable the microorganisms like mold spores, bacteria, viruses, and fungi. This light alters the DNA of microorganisms that deactivates or destroys them. When UV radiation neutralizes the microbes, these microbes lose their ability to harm humans and become inert to the surroundings.
When this UV light is used in an air purifier, a particular bulb is used that is responsible for this radiation. These bulbs produce UV-C that constitute the germicidal range of wavelengths in the UV spectrum. To protect humans from harmful rays of UV light, the UV light is contained uniquely within the purifier. Thus by this principle, the air is passed through the UV-C that kills pathogens present in the air. This principle is effective by 99.9% and is used widely across the world.
Some of the points that bring out the disadvantages in the purifier systems are -
1) The addition of a UV bulb to the air purifier setup costs a lot of money with regards to the initial purchase and maintenance of the system.
2) Care must be taken to ensure that the microbes are exposed for a prolonged duration under the UV-C light and are positioned so that all the microbes are affected by this.
3) As bulbs in the purifier wear out frequently, constant vigilance should be maintained so that the process keeps going on.
4) Air purifiers should be constructed carefully so that insulated wires and plastic materials do not come into contact with UV-C light. This is because high-intensity UV light can damage the plastic material like the plastic bodies of the purifier, releasing toxic gases into the atmosphere. This could lead to airborne contamination.
5) High-efficiency Particulate Arrestance (HEPA) filtration systems are accurate enough to trap 99.97% of particles or particles having a diameter as small as 0.3 microns. This shows the filtration system's effectiveness, and this effect is because of the process called diffusion. HEPA filters trap the tiniest particles by this diffusion, implying that it is more effective and advantageous than UV light air purifiers.
UV Air Purifier vs. HEPA Filters
UV Air Purifier: These air purifiers use UV-C lamps to disinfect the air polluted by airborne viruses, bacteria, mold spores, fungi, allergens and dust mites. These are installed as stand-alone clean air devices or are installed into the HVAC in residential or commercial units. UV-C light destroys the microbes that pass through the UV-C light waves. The UV-C produces a light of wavelength 254 nanometers, and when shielded properly is completely safe to use in occupied spaces. Unlike HEPA filter units, UV-C destroys airborne pathogens while HEPA filtered units trap the pathogens leaving the user with the responsibility to dispose of them safely.
HEPA Filters: High-efficiency Particulate Arrestance (HEPA) filter systems are constructed of randomly oriented fibers or glass designed to trap particles from bacteria, viruses, pollens, allergens, etc. As per International Organization for Standardization (ISO), HEPA filters must remove 99.95% of contaminants, and as per US Standards, HEPA filters must remove 99.97% of pollutants. The standards for HEPA are based on the Most Penetrating Particle Size (MPPS) of 0.3 microns implying that the filter must eliminate 99.97% of contaminants that are greater than or equal to 0.3 microns. Since HEPA filters trap every particle that comes into contact, it is recommended that Personal Protective Equipment (PPE) be used when replacing the filters in the filter system.
UV Air Cleaner vs. HEPA Air Cleaner: Which Do You Need?
As per Environmental Protection Agency (EPA), the indoor environment is 2 to 5 times more polluted than the outdoor environment. Thus, air cleaners prove effective in this case. Some of them are -
UV Air Cleaners - These air cleaners follow the basic principle of eliminating pathogens, allergens, and harmful particles present in the air using ultraviolet light. It can be installed over the air conditioning system so that it kills the microbes and collects them. This is mainly done as the coils' coolness allows water to condense and generates a humid environment for bacterias and other microbes to grow. This will collect them and dispose of them off through ducts. UV Air Cleaners are mainly required for homes that are humid in summer, for people who prefer energy efficiency as disposal of the microbes decreases energy efficiency and for someone who is allergic to microbes.
HEPA Air Cleaners - High-efficiency Particulate Arrestance (HEPA) filter systems consist of a series of filters with fans and can remove the tiniest of particles that harm the environment. It can remove 99.97% of the pollutants from the environment and microbes having a minor diameter of 0.3 microns. Some HEPA air cleaners also contain UV light to remove bacteria and viruses. HEPA Air Cleaners are mainly required for families with high allergies, for people concerned about the air quality of their homes, and for people who want hospital clean air in their homes.
How much area can a UV Air Cleaner clean?
UV Air Cleaner comes in four sizes, and customers buy these based on the sizes of their homes measured in square feet. These are -
1) Small UV Air Cleaner - Such cleaners are best suitable for homes having sized up to 200 square feet. It is also best for personal spaces.
2) Medium UV Air Cleaner - Such Cleaners have the capacity to clean homes having a size between 200 square feet to 400 square feet.
3) Large UV Air Cleaner - Such Cleaners have the capacity to clean homes having a size between 400 square feet to 1500 square feet.
4) Whole-House UV Air Cleaner - Such Cleaners have the capacity to clean every room in the house, be it a villa or a farmhouse.
What makes the RXair400 the best air purifier on the market?
RX air400 is the best in the market because of its ability to clean the air as fast as eight times per hour, killing the microorganisms that contaminate the air. In this way, even if the asymptomatic patient carrying the disease doesn't wear masks, then RXair400 eliminates the pathogens released from the infected patient. RXair400 is certified both by Environmental Protection Agency (EPA) and Food and Drug Administration (FDA). RXair400 kills 99.99% of pathogens and removes bacteria and viruses that cause diseases like influenza, streptococcus, whooping cough, allergies, tuberculosis, etc. Apart from this, RXair400 is smaller in size and contains an ergonomic handle that offers portability.
Are UV air purifiers better?
Compared to traditional air purifiers, UV air purifiers are better in many ways. Traditional ones need a constant level of airflow to eliminate pathogens and are less efficient than UV air purifiers. Traditional ones pull air through filters and dispose of it through the vent. This variates the airflow in the room while a UV air purifier keeps the airflow constant without harming the environment. Also, the tiniest of particles like bacterias, viruses, fungi get removed with the help of UV air purifiers, while traditional air purifiers are less effective.
Are UV air filters safe?
Most commonly, it is said that UV air purifiers transform oxygen into ozone and produce poisonous gases. But it's not true as modern air purifiers are designed to handle and dissipate ozone without harming the environment. These are typically marketed as “ozone-free” UV light purifiers. These UV air purifiers dispose of germs and viruses and clean the air to breathe.
Are UV air purifiers dangerous in any way?
UV air purifiers are helpful as well as dangerous at the same time. UV rays do not entirely kill the pathogens as constant air circulation occurs through ducts and vents, so not much contact time is there for the complete removal of the allergens, bacterias, viruses, and molds. In some UV air purifiers, it is seen that the oxygen is converted into ozone. Since air circulation occurs within the room, it's possible to leak ozone gas into the atmosphere making the environment harmful. Airborne pathogens are not killed thoroughly, so the air is cleaned to some extent only.
What is the difference between air filtration and purification?
Air Filtration: It is the method of separating airborne particles like dust, mites, pollens, etc., from the atmosphere with the help of filters installed over the air conditioners present in residential or commercial complexes. The filter attracts and disposes of the particles before the air is dispatched through the duct to every room in the unit. Two primary filters are -
1) High-efficiency Particulate Arrestance (HEPA) filters - These filters have the efficiency of removal up to 99.97% and even tiniest particles up to 0.3 microns. Only air conditioners rated to work at 16 or higher efficiency levels can render HEPA filters victorious. However, good quality low rated filters can also cause HEPA filters successful. HEPA filters can also be accommodated with vacuum cleaners to clean household items like carpets, floors, and many more.
2) Minimum Efficiency Reporting Value (MERV) filters - These filters work in the efficiency range of 1 to 16, with 1 being the lowest and 16 being the highest. It depends upon the size of the room where it is to be installed.
Air Purification: It is the method of disinfecting the air by counterbalancing pathogens such as bacterias, viruses, molds, and fungi. In this method, the purification system some chemicals to kill, nullify, or alter the DNA of the pathogens to make them harmless. One of the frequently used Air Purification systems is UV air purifiers that kill pathogens using UV light rays. This mechanism resembles the action of the sun that utilizes UV rays in killing germs. Here, the toxins or odors produced by the pathogens are eliminated by the UV rays, thereby giving out clean and fresh air. Two primary types of air purifiers are -
1) Portable units - These units are designed to clean the environment of a small room less than 900 square feet. However, in large rooms or offices, installation of portable units is required separately.
2) Central units - These units are designed to work with HVAC and furnace systems. Mostly these are installed on air conditioners or air ducts to clean the air accumulated on them. The unit size cleaned by them ranges from 1700 square feet to 4000 square feet.
Do all air purifiers use UV light?
No, all purifiers don't use UV light for disposing of microbes. One such purifier is High-efficiency Particulate Arrestance (HEPA) filters that use filters to remove pathogens from the atmosphere. Another one is Activated Carbon Air Purifiers use carbon to absorb all the dirt present in the atmosphere and clean the air. These are very effective in removing odors and smells. The Ionic Air Purifier is another type that emits negative ions into the atmosphere that combines with positive ions like dust, mites, and other particles, making these particles heavy to dispose of quickly through ducts.
Are UV air purifiers effective?
UV air purifiers are very effective as they clean the air by using ultraviolet light rays to kill the microbes present in the air. These cleaners effectively keep the environment odor-free as they alter the DNA of microbes, making them entirely harmless. These cleaners are usually installed over air conditioners that collect microbes and pass through vents.
Do UV air purifiers really work?
As per studies, UV air purifiers really work well in cleaning the air. It has been observed that UV-C light works well for a particular duration and intensity that helps in disabling pathogens by altering their DNA. It also helps in preventing allergies by removing all the allergens from the air. One type of UV air purifier is RXair, which provides accurate killing pathogens as certified by Environmental Protection Agency (EPA) and Food and Drug Administration (FDA). RXair removes pathogens, microbes, and VOCs (Volatile Organic Compounds). It is a powerful purifier as it kills 99.99% of pathogens that cause diseases like influenza, H1N1, multiple Coronavirus strains like SARS and the common cold, tuberculosis, measles, and many more. It removes bacteria that cause respiratory problems and strengthens the immune system.
Can you see the uv light at night in the air purifier?
UV light rays are far away from the visible spectrum, and so it is not visible to the human eye. Retina's photoreceptors are conscious near-UV. Since humans lack a lens to see the UV rays, we can perceive near-UV as whitish blue or whitish-violet colors. Near-UV rays are visible to birds, some mammals, and insects.
How can I find the best air purifier for home use?
Home purifiers come in various ranges depending upon the size of homes. UV air purifiers effectively remove airborne pathogens by inactivating, neutralizing, or killing them with UV light rays. These cleaners are placed on air conditioning systems that circulate the airflow and keeps the air clean. But if a person has severe allergies, then HEPA filters can be used as it has an efficiency of 99.99% and can eliminate particle size as small as 0.3 microns. For small rooms, portable UV air purifiers effectively clean the air.
In contrast, centralized air purification systems can be installed to circulate clean air throughout the house. UV air purifiers have germicidal UV lamps that attract pathogens and kills them. It eliminates the smell and odor from the atmosphere keeping the air fresh.