The air chamber, a giant Teflon bag in Jimenez’s lab. (Courtesy of Cassie Sherwood)
In a third-floor laboratory at the University of Colorado Boulder is an airtight room whose walls are lined with tanning bed lights. The lights point at a large, cube-shaped, clear bag with what appears to be nothing inside. But there is something inside: air.
In this lab, Jose-Luis Jimenez, a distinguished professor of chemistry, and his graduate students are conducting research that could change the way we fight the spread of deadly diseases like Coronavirus.
Some may know Jimenez for his posts on the social media platform X. He gained an online following by posting about indoor air quality, especially during the onset of the COVID-19 pandemic. Jimenez regularly posts photos of the readings from an Aranet air sensor in different public spaces like buses, airports and school gymnasiums to educate followers about ventilation.
Rebecca Mesburis puts the catalyst inside the air chamber. (Abby O’Brien/ CU Independent)
Jimenez also gained attention online for reposting examples of bad COVID policies by governments and organizations in a list he called the ‘COVID Hall of Shame.’ He was outspoken on social media about how organizations like the World Health Organization gave false statements about how COVID wasn’t airborne, even though research found that it was.
“He got really famous during the pandemic,” said Rebecca Mesburis, a PhD student who conducts research in Jimenez’s lab. “He’s a little embarrassed.”
In his clear Teflon cube, Jimenez measures the effects of ultraviolet light on airborne pathogens like the COVID virus. Research shows that UV light is highly effective at killing pathogens. A type of short-wavelength UV, called germicidal ultraviolet light, promises to drastically reduce those pathogens without causing significant damage to human skin or eyes. The technology has recently gained traction as a possible indoor air sanitizer, especially since the onset of the pandemic.
However, the use of GUV indoors creates ozone, a harmful pollutant. Ozone also leads to the formation of particulate matter and other pollutants that are harmful to humans, especially in poorly ventilated spaces. Jimenez has published research linking GUV lamps to dangerous levels of ozone and other pollutants.
A Germicidal Ultraviolet (GUV) lamp in the lab. (Courtesy of Cassie Sherwood)
“Some medical workers think they should be everywhere: every classroom, every office, every bus,” said Jimenez. “From a disinfection point of view, they’re right. But the problem is that they also make a lot of pollution, and pollution kills people. So you’re saving people from dying one way but killing them softly the other way.”
To some, GUV can seem like a tempting way to combat the spread of airborne disease – especially during a pandemic, for example, when high rates of death caused by viruses like COVID are easy to track and measure. But deaths caused by exposure to pollution, especially any one pollutant in particular, can be harder to measure.
Jimenez used an analogy to explain the potential problems. He proposed a situation in which a person installs a GUV lamp in their home and dies from ozone exposure five years later.
“Of all the things you did in your life, how do you know that it was the lamp that you have in your living room versus you like (to eat) hamburgers, or you smoke or whatever other things you did,” he asked.
In 2023, Jimenez presented his findings – that GUV lamps create unhealthy levels of ozone – at the First International Congress on Far-UVC Science and Technology. He hopes he can discourage other experts and the public from too hastily installing GUV lamps in homes and businesses before more science can be published on the subject.
Now, Mesburis, the PhD student, is studying a possible solution to that ozone problem: a catalytic decomposition material.
The catalytic decomposition material is something that could be used in combination with a GUV lamp to reduce the ozone after it’s formed and keep the air safe to breathe.
PhD student Rebecca Mesburis holds the catalytic decomposition material. (Courtesy of Cassie Sherwood)
The material is aluminum honeycomb, which provides a substrate for air to pass through, coated in manganese dioxide, which is the ozone decomposition catalyst itself. When airborne ozone comes into contact with the catalyst, it’s converted into molecular oxygen.
Mesburis is studying the result of that interaction between airborne ozone and the manganese dioxide catalyst in order to determine whether any harmful compounds are created in the reaction. If no harmful byproducts turn up in her research, she is optimistic about what it could mean for GUV lamps as a health solution.
“The implications would be that this combined with the GUV lamps would be a really great combination for improving indoor air,” said Mesburis. “You’d be reducing disease, you’d be reducing ozone and you’d be reducing a bunch of other indoor air pollutants.”
Rebecca Mesburis holds up the catalytic decomposition material. (Abby O’Brien/ CU Independent)
Mesburis’s research has already found that the manganese dioxide catalyst removes formaldehyde and nitrogen dioxide, two common air pollutants that are dangerous to human health. Another benefit of the material is that it’s relatively cheap, meaning it could be an accessible household solution.
The study is set to be published in 2025. Jimenez is also optimistic about the combination of GUV lamps and manganese dioxide catalysts.
“I’m on the verge of putting one in my home,” he said.
But Mesburis’ and Jimenez’s forthcoming paper won’t necessarily give the green light for GUV lamps to start being used in every hospital and home. Other consequences of the technology, like whether it could be killing anything beneficial in the air, have yet to be studied.
Contact CU Independent Staff Writer Abby O’Brien Abby.o’brien@colorado.edu
