Copyright Boulder Daily Camera
Imagine switching on a light at home that can disable airborne allergens within minutes. The unstoppable sneezing, itchy skin and swollen eyes finally ease up. Well, a team at the University of Colorado Boulder found that it actually is that easy. The team found that common allergens found in homes, such as allergens from cats, dogs and dust mites, can be disabled by simply switching on a UV light. “The wavelengths of UV light disrupt the protein and denature it, and the body no longer recognizes it as an intruder,” engineering professor Mark Hernandez said. Allergens are made out of protein, Hernandez said, which the body sees as an intruder, thus initiating an immune response even though the allergen won’t actually harm the body. The short wavelength of the UV light is what disrupts the proteins, Hernandez said. “It’s that easy,” he said. UV light is already used widely to disinfect surfaces for bacteria and viruses in hospitals, for example, but the strong wavelength requires people to wear equipment to protect their skin and eyes. The study used 222-nanometer-wavelength lights, or UV222, a less-intense alternative. Vendors such as Amazon also sell less intense UV lights for home use. Anyone could buy one of these UV lights online, Hernandez said, and start using them in their home. For the study, the researchers placed UV lights inside a chamber that’s about 10 cubic meters, or the size of an average home bathroom. They then sprayed in airborne allergens from mites, pet dander, mold and pollen, and analyzed the response. The allergens were either exposed to the UV light or left untreated in a control chamber. After 30 minutes of exposure to the UV light, airborne allergen levels effectively decreased by about 20% to 25% on average, the study showed, compared to the allergen levels in the control chamber. Efficacy depended on factors such as the type of allergen and how long the light was on, but in one condition tested, the cat allergens had decreased by 61% after 40 minutes of UV light exposure. Prior work has been done on surfaces, Hernandez said, but this is the first time a study has worked with UV light and airborne allergens. That is just one project of many in Hernandez’s indoor air quality lab. Through the Colorado Department of Public Health and Environment’s Clean Air for Schools Program grant, the lab has put air filters with high-efficiency particulate air, or HEPA, filters in about 30,000 classrooms across the state. The CU Boulder team has partnered with CU Anschutz to see if improved air quality will help with student absenteeism. “I prioritize work in public schools and late-life care facilities where folks don’t have an option to be there, they’re there a lot and they’re exposed to whatever is in the setting,” Hernandez said. “We can measure and manage that with engineering interventions.” Postdoctoral researcher Emily Kraus is working on a study about respiratory viruses on desktops in Colorado elementary schools. She’s looking at the prevalence of viruses like COVID, flu and RSV and trying to determine if HEPA filters are making a difference in classrooms. Using the same chamber as the allergy research, Kraus also studies pathogens in the air. She tries different methods to kill them while they’re in the air or analyzes their genetic sequence while they’re in their airborne state. When microbes are challenged, they have a genetic response, and she deciphers that. The lab is unique by having that chamber, which allows for microbial testing under controlled temperature and humidity. It’s a capability rarely available in academic labs, according to Hernandez. The lab can simulate, in the chamber, what happens when a sick person coughs out bacteria in their lungs. The person coughs it out, the bacteria go flying, and while they’re flying, they are changing what they do to survive in the air. Kraus is trying to figure out what those changes are. Scientists can see that the bacteria change their activity pattern, but no one has been able to figure out what, exactly, the bacteria is doing. “And it’s on the order of five to 20 seconds,” Kraus said. “They can respond, they know they’re being coughed out, they switch their molecular mechanisms internally, and then they are prepared to survive the airborne state until they land in a host, basically.” Scientists don’t know or agree on whether microorganisms can survive and thrive in the air. Most people think they just travel through the air until they end up on a surface or a person, Kraus said. She wants to know if they can survive and thrive in their air, if they can be fed or even reproduce. “This is a fundamental biology question of trying to understand how pathogens move between humans,” she said. It’s hard to study airborne particles because everything in the air has a low biomass, Kraus said, meaning it’s easily contaminated with cells from the researcher or from the lab. Sampling well and without contamination is difficult, and she specializes in doing so very cleanly.
