Ultraviolet light can reduce allergens faster than months of cleaning

Most people expect a deep breath indoors to feel safe. For allergy sufferers, it rarely feels that way. A whiff of dust or cat dander can quickly lead to itchy eyes, wheezing lungs, and restless nights. What makes it worse is that allergens do not leave when their source does.

Tiny proteins float through the air and settle into furniture, rugs, and walls. Weeks later, they still provoke reactions. This stubbornness has long frustrated doctors and patients alike. Cleaning helps but rarely keeps up. Medications reduce symptoms but don’t remove the cause.

A group of researchers at the University of Colorado Boulder has now tested a new approach. Their idea sounds almost futuristic: switch on a light, and allergens lose their power.

Ultraviolet light weakens allergens

“We have found that we can use a passive, generally safe ultraviolet light treatment to quickly inactivate airborne allergens,” said Tess Eidem, a senior research associate in the Department of Civil, Environmental, and Architectural Engineering.

“We believe this could be another tool for helping people fight allergens in their home, schools or other places where allergens accumulate indoors.”

The work shows how a narrow band of ultraviolet light weakens allergens in the air. Unlike dust mites or mold spores, proteins are not alive. They cannot be killed. But their structure can be altered so the immune system fails to recognize them.

Allergies begin with proteins

Allergic reactions start with proteins. Cats, for example, produce a protein called Fel d1 in their saliva. It spreads as they lick their fur and clings to skin flakes that drift through the air.

Once inhaled, the protein’s unique shape tells the immune system to respond. Sneezing, coughing, and swelling follow.

The same story plays out with dogs, dust mites, mold, and plants. Each produces its own protein trigger. These proteins last long after the organisms themselves vanish.

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

Cleaning doesn’t stop all allergens

Vacuuming, air filters, and constant scrubbing can reduce allergen levels, but none provide lasting relief. Many people eventually give up or fall behind on the routines. That leaves exposure unchecked.

Eidem and her colleagues, Professor Mark Hernandez and microbiologist Kristin Rugh, looked for another path. Instead of removing allergens, they tried changing their structure. If a protein’s folded shape is disturbed, the body cannot detect it.

“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,” explained Eidem.

Safe wavelength explored

Ultraviolet light already kills bacteria and viruses. Hospitals rely on it to disinfect equipment. But the standard wavelength, 254 nanometers, is too strong for daily life. Prolonged exposure damages skin and eyes.

Eidem’s group tested a milder wavelength – 222 nanometers. This version, known as UV222, is considered safe for spaces where people are present. It does not penetrate deep into human cells, though it can create small amounts of ozone.

The team filled a sealed chamber with allergens from mold, pollen, dust mites, and pet dander. Four UV222 lamps shone across the room. Samples of the air, taken every ten minutes, showed clear changes.

Allergens reduced quickly

In untreated air, antibodies clung tightly to the proteins. In the treated chamber, many proteins no longer attracted antibodies. After just half an hour, allergen recognition dropped by 20 to 25 percent.

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

The results suggest ultraviolet light doesn’t just disinfect. It can also reshape proteins so they no longer trigger allergic responses.

Practical uses for UV light

UV222 lamps already exist for industrial purposes. Eidem imagines portable versions for homes and workplaces. Someone could carry a small device when visiting a friend with pets or use one before tackling a dusty room.

Workers who handle animals or spend hours in greenhouses could also benefit. In cannabis facilities, where Eidem’s earlier research showed severe allergic reactions, such protection might even save lives.

Allergies affect millions

One in three Americans lives with allergies, according to the Centers for Disease Control. For many, allergies are not minor. They can lead to asthma, a disease that sometimes proves deadly.

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

The study offers a hopeful step. Ultraviolet light, used safely, might give millions a new way to control allergens.

The study is published in the journal ACS Publications.

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