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Do UV lights kill COVID-19 in air conditioning systems?

Central Florida governments have already spent hundreds of thousands of dollars

ORLANDO, Fla. – Since the start of the coronavirus pandemic, hundreds of thousands of dollars has been spent by Central Florida government agencies to install ultraviolet light systems inside their heating and air conditioning systems.

“Light has been killing germs since the beginning of time,” said Terrance Berland, CEO of Violet Defense.

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He said his downtown Orlando-based company has been hard at work harnessing that ultraviolet light to fight the coronavirus.

The company’s work in UV sanitization is already being used by the Orlando Magic and the New York City subway system.

“Oh, it definitely kills COVID-19,” Berland said.

Diagram shows how researchers say UV light kills the DNA inside the coronavirus.
Diagram shows how researchers say UV light kills the DNA inside the coronavirus. (Copyright 2020 by WKMG ClickOrlando - All rights reserved.)

Berland said his researchers have shown when UV light is exposed to the coronavirus on surfaces, it can kill its DNA, preventing it from reproducing.

But can it do the same thing in air conditioning systems?

News 6 found at least three public agencies approving funds for UV light installation in their HVAC systems.

Volusia County approved $251,918 for installation and equipment in June.

Marion County approved $216,830 for a similar project the same month.

In September, Orange County Public Schools approved a $13.2 million proposal to install UV lights in HVAC systems in their schools.

“If you’re trying to keep your cooling coils clean, and you’re trying to make sure you don’t have a biofilm that’s built up, it’s fantastic,” Berland said. “If you’re trying to clear the air, it’s really suspect.”

The U.S. Food and Drug Administration took it one step further on its website.

“There is limited published data about the wavelength, dose, and duration of ultraviolet radiation required to inactivate COVID-19,” the website reads.

But within the past few weeks, OCPS altered its plans.

“We changed our mind on what we’re going to do first,” said Orange County School Board Chair Teresa Jacobs.

She said after looking at the research and after having conversations with the Orange County Schools Medical Advisory Board, the district opted to hold off on installing UV lights in the air conditioning system.

Instead, she said the district will install CDC-recommended air filters that are rated MERV 13 and MERV 9.

Marion County defended its decision, but admitted it’s not a silver bullet to killing the coronavirus.

“Marion County was ahead of the curve in implementing UV-C air purification technology at every air handling system in the county,” said county spokesman Alex AuBuchon. “Although at the time these systems had not been specifically tested against SARS-CoV-2 (the newly discovered coronavirus that causes COVID-19), the technology we vetted and chose to implement was proven effective at destroying a wide variety of bacteria and viruses including other coronaviruses. Since then, the system we installed has, in fact, been demonstrated effective at destroying SARS-CoV-2. We do not take the expenditure of taxpayer funds lightly, and we believe this technology is an investment in the long-term health and safety of our residents and our employees.”

Volusia county officials agree, it’s an added layer of protection in the fight with COVID-19.

“At the peak time of the summer spike in new COVID-19 cases, there hadn’t been much study of the effectiveness of Ultraviolet Germicidal Irradiation (UVGI) in inactivating the novel coronavirus SARS-COV-2,” said county spokesman Gary Davidson. "However, studies regarding the effectiveness of UVGI on bacteria, fungi and other coronaviruses such as SARS were available at the time, and they showed that UV-C energy (in the wavelengths from 200 to 280 nm) provide the most germicidal effect, with 265 nm being the optimum wavelength. In short, UVGI inactivates microorganisms by damaging the structure of nucleic acids and proteins – with the effectiveness dependent upon the UV dose and the susceptibility of the microorganism. In addition, the CDC manual for infection control indicated that UVGI could be used as an adjunct air cleaning measure (not to replace HEPA filtration). The information available at the time also indicated that among UV-A/B/C spectrum, UV-C wavelength was the most effective at rapid inactivation and disinfection. Studies also showed an overall improvement in air quality and a reduction in organic matter collection in filters, resulting in improved environmental conditions and lowered maintenance costs.

“We realize that UV-C AHU lighting project wasn’t the total solution in the fight against COVID-19,” he said. “But based on the information cited above, we’re confident that it does serve as an added layer of protection to reduce overall viral load in addition to having added environmental benefits. With so many other health factors to consider, such as cold season, influenza, asthma and mold spores, we strongly believe that providing the public and our employees with high-quality air through the use of UVGI technology was a worthwhile investment.”

The University of Central Florida also installed a similar system.

“UCF’s use of ultraviolet germicidal irradiation within building ventilation systems is just one piece of the university’s comprehensive strategy for limiting the spread of COVID-19," said spokesman Mark Schlueb. "We’ve also increased ventilation to continuously flush buildings with fresh outside air, installed higher-efficiency filters, reduced classroom capacity; mandated facial coverings and social distancing on campus, and enhanced cleaning and sanitizing practices. Based on expert guidance, we are confident the use of UV-C lighting has increased the effectiveness of the university’s multi-tiered approach. To date we have seen no spread of the virus resulting from our classrooms.”

Here are some additional resources studying the effects of UV lights in heating and air conditioning units:


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