How Do UV Light Indoor Air Quality Products Work?
UV lamps emit UVC radiation to disinfect nonporous surfaces, air, and water. For many years, UVC radiation has been used to reduce the spread of viruses and bacteria such as tuberculosis. Thanks to their ability to kill microorganisms, these lamps are referred to as germicidal lamps.
What Determines the Effectiveness of UV Lamps?
The ability of a lamp to destroy microorganisms has a few limitations.
For starters, for a lamp to damage the coating of viruses and the DNA of other microorganisms, the organism has to be directly exposed to the light. The lamp needs to shine on the organisms to damage their coat or their DNA. Most of these units install in the HVAC system of your home where they clean air that flows over the coils or through the ducts.
The duration of exposure also determines how effectively the lamp kills microorganisms. Most of the lamps used in homes are of low dose, and they may take longer to inactivate microorganisms. As such, the air needs to circulate through the HVAC system severally for the lamp to inactivate all the microbes.
The wavelength of the UV light emitted also determines the effectiveness of the lamp. Short-wavelength light (UVC) is the most effective as it has the most energy. According to EPA, most lamps emit UV light at about 250 nanometers in wavelength. This is enough to inactivate most microorganisms, but there are some lamps that emit high wavelength light.
Types of UV Light Emitted by Lamps
UV light is in three categories; UVA, UVB, and UVC. Most lights emit UVC as it is the most potent and hence most effective. However, some lamps emit UVA or UVB.
UVA has a wavelength of between 315 and 400 nanometers. The FDA estimates that UVA is 1000 times less effective at inactivating viruses compared to UVB and UVC. UVA is less hazardous and the most abundant form of UV from the sun. When one is exposed to this light, their skin may age and be at risk of skin cancer.
UVB is more effective at inactivating viruses and microorganisms than UVA, but less effective than UVC. This form has a wavelength of between 280 and 315 nanometers. The light can destroy microorganisms, but they need to be exposed to it for longer than they would to UVC to get destroyed. UVB is more hazardous to human beings as the earth’s atmosphere allows up to 5% to penetrate through. When exposed to it for a long time, the light causes sunburn and can also affect the eyes. It also destroys DNA, which is how it inactivates microorganisms and can cause skin cancer.
UVC is short wave light that has enough energy to inactivate microorganisms. The UVC from the sun does not penetrate the earth’s surface. This makes it safer for human beings. Unless you are exposed to UVC from your lamp, the UVC from the sun has no effect on you.
UVC has a wavelength of between 100 and 280 nanometers. Because photons vibrate faster and closer together, the light has enough energy to damage molecules that absorb it.
The FDA notes that the use of UVC lamps can help homeowners damage the coat of the SARS-Coronavirus and bacteria such as tuberculosis.
Are UVC Lamps Safe for Home Use?
UVC lamps are manufactured safely. As long as they are installed right, they are safe for home use. The effects of these lamps will depend on the dose and wavelength of the light they emit and the duration of exposure. However, when they are installed inside the HVAC system and have the necessary coating, they will never cause any harm to users.
They can only harm you if you are directly exposed to the light. If exposed, they cause eye injury and burn-like skin lesions. Our technician at Hoff Heating & AC will install the lamp inside the HVAC system so that you never get a chance to look at it directly. This way, you are safe at all times.
Manufacturers use powerful shatter-proof glass and then add another coat to protect you from radiation. Even if the glass shatters, the coating absorbs the light to protect you.
There are lights that may generate ozone. Again, this only happens if the light doesn’t have the necessary coating to protect you. Ozone irritates your airway. It is produced when the UV light splits the free oxygen in the air.
Most UV lamps contain mercury. The mercury is embedded on the sides of the tube or is free within the tube. Mercury is hazardous even in small amounts, so you need to be careful when cleaning or disposing the lamp. You can also let a professional clean and replace the lamp for you routinely.
The FDA regulates UV lamps through their department, the Electronic Product Radiation Control Provisions. All manufacturers have to meet regulations set by the FDA, and this is how you know the lamps are safe.
Are All UV Lamps the Same?
UV lamps are different, depending on the wavelength of UV they emit. Some emit UV light at 254 nanometers while others emit at 222 nanometers. Most emit invisible UVC, others emit infrared, and others emit visible light.
The wavelength of the light determines its effectiveness and the health and safety risks that come with the lamp. There are also lamps that emit layers of wavelengths, making them effective at inactivating several organisms.
Types of UV Lamps
Low-Pressure Mercury Lamps – These lamps are still very common even though newer lamps are replacing them. They are the original UV lamps that emitted 254-nm UVC radiation. They have mercury embedded or free in their tube and emit UVC radiation when they heat to about 1292 degrees.
Excimer lamps – These are the most powerful lamps with a wavelength of about 222 nanometers. They are also referred to as Far-UVC lamps.
Pulsed Xenon Lamps – These lamps emit a pulse of broad-spectrum, including UV radiation, infrared, and visible light. However, most manufacturers filter the light so that the lamp only gives UVC light. They are common in hospitals and food processing areas where they are used to disinfect surfaces. In most cases, these lamps are switched on when no human being is in the area.
Light-emitting diodes (LEDs) – LEDs are loved for their energy efficiency. They emit a narrow wavelength radiation band. They peak at 256, 273, or 280 nanometers. This means that although they save energy, they are the least effective in inactivating microorganisms. Organisms need to be exposed to the light for a long time to be destroyed. They contain no mercury, and they are ideal when you need to disinfect delicate surfaces such as plastics.
These lamps purify your indoor air. However, they do not replace the HEPA filtration system. Instead, they are installed downward to the HEPA filter so that the air that comes to the UV lamp first goes through the filter. You can install it near the coil to clean it of bacteria, viruses, and fungi that may propagate on it. You can also install it in your air ducts.
Contact Hoff Heating & AC Today!
At Hoff Heating & AC, we offer installation, repair, and maintenance services for your HVACR and plumbing systems in O’Fallon, MO and surrounding areas. Call Hoff Heating & AC and speak to a professional.