UV air purifiers are safe.
Are UV Air Purifiers Safe?
Ultraviolet light from the air purifier is safe, as long as you are not directly exposed to it. Most UV air purifiers use short-wavelength UVC light to destroy pathogenic microorganisms like mold, germs, bacteria, and viruses. It is harmless to use daily, with no chemical byproducts to worry about. You will sleep better, breathe better, and enjoy better air quality throughout the day.
That being said, all UV light will emit insignificant ozone under the 0.070 ppm 8-hour limit approved by the California Air Resources Board (CARB) and EPA. Ozone (O3) is a dangerous, highly reactive gas composed of three oxygen atoms. Through photolysis, air exposed to UV light can create ozone, where nearby oxygen will break apart and attach to other oxygen molecules to form ozone (O3). Exposing to even a small amount of ozone can lead to chest pain, coughing, shortness of breath, wheezing, inflammation, and throat irritation. In the long run, it can aggravate asthma and cause irreversible damage to our respiratory systems, like pneumonia, bronchitis, and lung scarring with reduced capacity. Children, elderly, asthmatic, and sick people with compromised immune systems will be more susceptible to ozone, so use cautiously.
The Hidden Danger With UV Purifiers
Many health agencies, including the FDA and EPA, have reservations about appliances like UVGI, ionizer that emits hazardous ozone gas byproducts. Improper handling of UV air purifiers can worsen indoor air quality instead of improving it. Besides the ozone concern, direct exposure to ultraviolet light can lead to skin burning, eye damage/ photokeratitis, premature aging, and skin cancer.
To prevent the air cleaning appliances from doing more harm than good, here are some easy tips on how to use a UV sanitizing device safely:
- According to World Health Organization (WHO) guideline, never sterilize your hands or any part of the skin with unknown UV light.
- Avoid unreliable, poorly made UV air purifiers that have the tendency to leak mercury and harmful UV during irradiation.
- Do not let children or pets go near a UV air purifier unsupervised.
- Never stare directly at ultraviolet light. Never point the UV light at other people’s eyes as well.
- Avoid purchasing aftermarket UV lightbulbs or lamps that may not follow the FDA Ultraviolet Index (UVI) safety ratings.
- CDC recommends installing UV disinfection in ductwork or at the ceiling to complement the existing air filter rather than replacing it.
- For commercial use, make sure all safety measurements are practiced and properly suited to operate special UV devices.
What Is UV Light?
Ultraviolet light is a form of electromagnetic radiation invisible to the eye. Derived mainly from the sun’s rays, three types of UV light (UVA, UVB, UVC) vary in frequencies and wavelengths. UV-A has the longest wavelength, between 315 to 400 nm, followed by UV-B, with a wavelength between 280 to 315 nm. UV-C has the shortest wavelength, between 100–280 nm, with the fastest vibration and energy level.
UV technology is used in commercial applications such as hospitals, healthcare centers, beauty salons, meat processing plants, factories, and laboratories. Most sterilizing devices, including air purifiers, use broad-spectrum UV-C light because it is the most effective in disinfecting biological pollutants. When indoor air is forced into the air purifier’s internal chamber, the UV-C light irradiates short wavelength 254nm to break down mold, bacteria, and virus DNA/ RNA. The fungi and microbes will be killed and inactivated, therefore incapable of reproducing and spreading allergies. The artificial germicidal light will also genetically damage COVID-19 RNA rendering it harmless.
The Effectiveness Debate
Another setback with UV technology is its efficiency. While there is no doubt UV air purifiers can inactivate germs, bacteria, viruses and stop them from multiplying, it takes around 12.5 seconds to kill 99.9% of the virus under ideal conditions. With the constantly moving airflow, it is unlikely the microbes will remain exposed in the internal UV chamber for minutes. Besides the UV-C Light exposure time, the pathogens will have to be close to the UV light bulb to be fully sanitized. Some microorganisms strain, like mold spores, is highly resistant to UV radiation and may even take longer to kill off. Ultraviolet light is not great in removing large particles like dust, hair, and dirt from the air. It is also ineffective against smoke, odor, and chemical fumes like VOCs. The material of the lightbulb, like phosphor, quartz, and LED, also plays a big part. Avoid any mercury-based lamp that poses hazardous risks. The ultraviolet light intensity/ dosage, the cooling effect of airflow, ACH, and room size, can also affect the UV irradiation performance.
The lack of standardized UV measurement against airborne pollutants is another common issue. Some manufacturers sell inferior products yet make up fake claims on the UV effectiveness to trick people into buying one. You should only purchase a HEPA air purifier with UV light from a reputable manufacturer approved by CARB and AHAM.
The Safer Option: UV + HEPA
Rather than entrusting entirely to UVC light, the better and safer option is to combine conventional HEPA filtration with UV technology, according to EPA. A HEPA air purifier can quickly capture 99.97% of airborne pollutants as small as 0.3 microns. The activated carbon filter will absorb smoke particles, chemicals, and fumes. The UV light will supplement the filtration by destroying 99.9% of trapped allergens, so there is no chance of the microbes multiplying and reintroducing back into the air. This combination can help slow down the spread of COVID-19 viruses, as recommended by CDC. A life-saving device during these unprecedented times.
When searching for a UV air purifier that is genuine, safe, and, more importantly, effective, there are many factors to consider. So instead of manually researching what's available in the market, click here for the best air purifier with UV light designed for home use.
The FDA regulates electronic products (non-medical and medical) that emit UVC radiation through the Electronic Product Radiation Control Provisions. Firms that manufacture, repackage or import medical devices in the United States must meet the definition of a medical device under section 201(h) of the Federal Food, Drug, and Cosmetic Act. Ask the manufacturer about the air purifier's health and safety risks, particularly ozone emissions, to ensure you are getting the real deal. Find out if the UV lamp material contains mercury, which can be hazardous if the lamp is broken. You can read more about UV radiation and disinfection in FDA website. Alternatively, contact 1-888-INFO-FDA, or the Office of Health Technology for more technical information. You can also refer to the complete reports and sources below.
What About Ionizer? Are They The Same?
While both are safe for home use despite creating little ozone, ionizers and UV air purifier use different technology to clean the air. Ionizers or ionic air purifiers release safe negative ions that adhere and pull down airborne pollutants. Do not confuse it with an ozone generator. UV air purifiers sterilize microscopic airborne pathogens leaving no traces behind. It is the superior and effective air cleaning method. You can learn more about the differences between ionic VS UV air purifiers here.