Ultraviolet Light Can Reduce Allergens Better Than Months of Cleaning

Allergy sufferers take every step possible to alleviate the misery caused by allergens. They install air filters, vacuum, scrub floors, and eliminate dust, all in an effort to avoid allergic reactions.

Allergy sufferers take extra precautions because they know that a brief inhalation of airborne allergens can cause swollen eyes, skin, wheezing lungs, and difficulty breathing. Repeated exposure to allergens can even lead to asthma, a life-threatening lung condition.

What allergy sufferers may not realize is that, no matter how hard they try to keep their spaces clean, allergens do not disappear when their source is removed. While cleaning helps, it isn’t easy to do it every day, especially for those with busy schedules.

All is not lost, however. A research team at the University of Colorado Boulder (CU Boulder) developed a method to help allergy sufferers with a simple flip of a switch. And, it all has to do with ultraviolet light.

“We have found that we can use a passive, generally safe ultraviolet light treatment to quickly inactivate airborne allergens,” Tess Eidem, the study’s author and a senior research associate in the Department of Civil, Environmental and Architectural Engineering, said in a news release. “We believe this could be another tool for helping people fight allergens in their home, schools, or other places where allergens accumulate indoors.”

How Do Allergies Develop?

Allergies begin with allergen proteins. Unlike dust mites or mold spores, which can be eliminated through various methods, proteins are not alive and cannot be killed. This is why allergic reactions occur in response to the proteins. For instance, some people say they are allergic to cats because they sneeze whenever they are near the animal. However, it’s really not the cat that they are allergic to; it’s more likely the airborne flecks of a protein that cats produce.

Cats produce a protein called Fel d1 in their saliva, and it spreads when they lick themselves and clings to microscopic flakes of dead skin that drift through the air, more commonly known as “dander.” When these particles are inhaled, the immune system creates antibodies that attach to the protein’s unique 3D shape and trigger an allergic reaction, according to researchers.

Similarly, dogs, mice, and plants all produce their own proteins, each with their own distinct structure. However, these allergens cannot be killed because they were never alive, unlike bacteria, viruses, and the cat-produced protein.

“After those dust mites are long gone, the allergen is still there,” Eidem explained. “That’s why, if you shake out a rug, you can have a reaction years later.”

What the CU Boulder researchers did was change the structure of the proteins to prevent the immune system from recognizing them.
“If your immune system is used to a swan and you unfold the protein so it no longer looks like a swan, you won’t mount an allergic response,” Eidem explained. UV light can do this, according to the study, which was published in August in the journal ACS ES&T Air.

The Power of UV Light

Previous studies have shown that UV light can eliminate airborne microorganisms, including the virus responsible for COVID-19.
It is already widely used to disinfect equipment in hospitals, airports, and other places. However, the bandwidth (a wavelength of 254 nanometers) is usually so strong that users must wear protective gear to prevent damaging their skin and eyes.

According to the CU Boulder study, researchers used UV 222-nanometer-wavelength lights, a less-intense alternative considered safe for occupied spaces because it doesn’t penetrate deep into human cells. Eidem noted that there are risks to using the UV lights, including ozone production, so exposure should be limited.

The team pumped microscopic aerosolized allergens from mites, pet dander, mold, and pollen into an unoccupied and sealed 350-cubic-foot chamber. Then they turned on four UV222 lamps, about the size of lunchboxes, on the ceiling and floor.

They collected air samples every 10 minutes and compared them to untreated, allergen-filled air through laboratory tests, and saw significant differences. In the treated samples, immunorecognition decreased, meaning the antibodies no longer identified many of the proteins and stuck to them.

The study showed that airborne allergen levels dropped by about 20% to 25% on average after just 30 minutes.

“Those are pretty rapid reductions when you compare them to months and months of cleaning, ripping up carpet, and bathing your cat,” Eidem said.

The Possibility of Portable UV Lamps One Day

While UV222 lamps are already in use, primarily for industrial antimicrobial purposes, Eidem envisions portable versions for homes and workplaces. For instance, someone could take the UV222 lamp when visiting a friend with a cat or use it when cleaning a dusty room. The lamps could also benefit workers who care for animals or work long hours in greenhouses. Not only that, but UV222 lights might even save the lives of people who work in cannabis facilities, where Eidem’s earlier research showed severe allergic reactions.

The Centers for Disease Control and Prevention report that 1 in 3 adults and children in the United States have allergies. Eidem hopes her research, and more to come, can offer them some relief —or even save lives.

“Asthma attacks kill about 10 people every day in the United States, and they are often triggered by airborne allergies,” Eidem said. “Trying to develop new ways to prevent that exposure is really important.”

Source Links:

https://www.earth.com/news/ultraviolet-light-can-reduce-allergens-faster-than-months-of-cleaning/
https://www.sciencedaily.com/releases/2025/09/250922074945.htm#:~:text=09/250922074945.htm