In a recent interview for the University of Maryland’s School of Public Health, Dr. Donald Milton shared his applied environmental health expertise regarding COVID-19 mitigation strategies like mask wearing. When asked what measures public places can employ to help mitigate COVID-19 spread, he explained, “We need to engineer our spaces to be safe. Installing highly effective UV light air sanitation systems is one way to go about it.” He then illustrated his point with this analogy: “We don’t drink water that hasn’t been through a purification system. But we breathe air that’s not purified all the time, and I think that needs to change.” Dr. Milton also shared that he predicts the common cold and the flu will be “big” this coming fall and winter.
With his prediction about the coming cold and flu season, Dr. Martin adds his voice to a growing chorus of experts warning of microbial challenges that lie ahead. Epidemiologist Lauren Ancel Meyers of the University of Texas recently told CNBC, “There is a lot of uncertainty about the 2021-2022 influenza season…Since our COVID mitigation measures prevented influenza transmission last year, there are not a whole lot of people who were recently infected. So we may be entering flu season with a higher level of susceptibility than usual, which could exacerbate the risks.” Lynette Brammer, team lead of the CDC’s Domestic Influenza Surveillance Team, agrees. When interviewed by CNBC, she noted that increases in respiratory syncytial virus (RSV) outside its typical season have led the CDC to prepare “for flu virus circulation to return to pre-pandemic levels…especially as community mitigation efforts continue to be relaxed.”
Applying COVID Lessons to Future Threats
The increasing likelihood of a difficult cold and flu season provides an excellent opportunity to apply lessons learned during COVID in the fight against ongoing threats. Over the course of the COVID-19 pandemic, understanding of virus transmission modes evolved dramatically. In an updated science brief released in May, the CDC noted that exposure to the SARS-CoV-2 virus occurs in three ways:
- Inhalation of fine respiratory droplets and aerosol particles
- Deposition of respiratory droplets and particles on exposed mucous membranes in the mouth, nose, or eye by direct splashes or spays
- Contact between mucous membranes and hands that have been soiled either directly by virus-containing respiratory fluids or indirectly by touching surfaces with virus on them
With the SARS-CoV-2 aerosolized virus, experts now know that the key ways to mitigate exposure risks are by decreasing virus concentration in the air through dilution (e.g., ventilation) and by driving down the number of viable virus samples through environmental factors (e.g., exposure to UV light). These same principles apply when fighting other aerosolized pathogens, like the influenza A virus and the common cold, which can be transmitted in ways similar to SARS-CoV-2.
Despite this understanding of how to manage risk, the reality is that many spaces have inadequate ventilation to produce dilution of the virus. Building HVAC systems also do not provide protection from viral spread in person-to person-transmission. Thus, in enclosed spaces with inadequate ventilation or air handling, the risk of any person-to-person disease transmission remains high. How can organizations, schools, and businesses manage ongoing risks while still operating safely?
Disinfecting Air with Arc Air’s UV Light
Although the CDC recommends making improvements to building ventilation as part of a multi-layered mitigation strategy, these approaches have limitations. Building ventilation improvements can be difficult to implement due to costs, time required, and the design and age of HVAC systems. A more immediate solution is the use of portable air purifiers, which are relatively inexpensive, simple to use, and easy to move from room to room. Two major types of portable air treatment systems are available. One type traps particles and pathogens, while the other type kills bacteria and inactivates viral pathogens. Air purifiers come with the caveat that their reliance on filters results in a catch rather than kill strategy for pathogen management. Furthermore, depending on the effectiveness of the filter, some pathogens can still escape and continue circulating in a space’s ambient air.
With these risks and realities in mind, R-Zero developed the Arc Air – a filter-less, portable air disinfection device that actively destroys airborne pathogens rather than merely capture them. As air passes through the Arc Air’s interior disinfection chamber, it is exposed to three 15-inch (non-ozone-producing) quartz UV-C bulbs. While studies have shown that it is possible for some HEPA to capture particles smaller than 0.3 microns (SARS-CoV-2 is 0.125 microns), Arc Air eliminates any uncertainty regarding effectiveness of a given filter and actively deactivates pathogens in the air, regardless of particle size. Furthermore, because the UV-C bulbs are contained within the Arc Air unit, the device can be placed safely in occupied spaces without risk of UV-C exposure. There is no UV light exposure emanating from the Arc Air, and the device does not produce any ozone.
To underscore the real-world efficacy of the Arc Air device, R-Zero recently completed a laboratory study to measure the effects of the Arc Air on ambient microorganisms in an office environment. While this study is not a substitute for the controlled laboratory testing done on this product, it nevertheless gives an “in situ”/real-world application of how well the Arc Air works.
Dr. Richard Wade, Chief Scientist for R-Zero, led the study. In explaining the basis for the test, he noted, “I wanted to do this study to see for myself if the unit would be effective for ambient air because most tests on the efficacy of UV light have been laboratory tests. So naturally questions come up when we speak with clients about what happens in the real world when you have ambient air circulating. By performing this study in an office environment, we can see and measure what’s in a real-world environment – what’s in the air going in and what’s in the air coming out.”
Per Dr. Wade’s study design, the test measured input air vs. output air entering and exiting the Arc Air unit to determine the degree of kill of ambient organisms such as gram- negative and gram-positive cocci. These classes of organisms contain some of the most significant human bacterial pathogens, which can include Staphylococcus aureus, Streptococcus pyogenes, and Strep. pneumoniae.
Studying the Arc Air in a Real-World Environment
An Arc Air unit was placed in a 12’x12’ office, in which no active HVAC was running at the time of the test. Viable gram-positive cocci and bacillus bacteria were found in this ambient room air, but no speciation was done on these bacteria. No viable fungal species were detected in the room ambient air.
For the test itself, the Arc Air was run at three different speeds (low, medium, and high). During three-minute sampling periods, the test utilized an Anderson air microbe sampler with a calibrated pump set at 1.5 cubic meter or liters per minute. The sampler device measured input air going into the Arc Air and exit air coming out of the top of the Arc Air.
To capture ambient air samples, laboratory-prepared agar plates were inserted into the sampler device, and the device was then connected to the vacuum pump. During each three-minute test period, the sampling device would deposit ambient air onto the sampling media through a 60-hole air dispersion designed into the sampler. The sampling device was sanitized between runs.
The test used two types of sampling media: one for total bacteria (gram negative and gram positive) and the other for the presence of viable fungal spores. After the completion of each test, the test plates were placed into a shipping container with ice and sent to the analytic laboratory with an accompanying chain of custody.
Proving the Efficacy of Arc Air’s UV Light Disinfection
The air test did not detect any viable fungal spores in the ambient air either at the Arc Air inlet or exhaust.
However, for the bacteria testing, the following findings emerged:
|Low||No ambient bacteria detected||No bacteria detected|
|Medium||Ambient bacteria detected: gram-positive cocci and rods||No bacteria detected|
|High||Ambient bacteria detected: gram-positive cocci and rods||No bacteria detected|
No ambient bacteria were detected on input at the low setting due to the limited air volumes sampled (total air sampled over three minutes: 53.7 ft3). At the medium and high settings, ambient bacteria were detected due to the higher volumes of air sampled over the three-minute sampling period.
The absence of bacteria at the output/exhaust at all settings demonstrates that the Arc Air was able to eliminate all detectable levels of bacteria found in the tested ambient air.
This real-world study reinforces Arc Air’s efficacy as a continuous air disinfection system for occupied indoor spaces. As the results demonstrate, unlike other air purifiers that use filters, Arc Air doesn’t just capture pathogens: it destroys them by leveraging the safe and proven power of hospital-grade, 254nm UV-C disinfection technology. Reviewing the test results, Dr. Wade commented on this distinction between catching pathogens versus killing them by observing, “We can measure and show that when air comes out of the Arc Air, the bacteria have been killed.. This test proved the efficacy of the Arc Air in a real-world environment.”
Crafting a Holistic Disinfection Strategy with Arc Air
These real-world results further strengthen the potency of Arc Air as a component in a layered approach to disinfection. As an FDA-cleared Class II Medical Device, Arc Air is designed to be used in tandem with R-Zero’s Arc. While Arc provides high-power, complete UV disinfection in unoccupied spaces (once to several times per day), Arc Air provides continuous UV air disinfection — offering protection from airborne pathogens while spaces are occupied, in between high-power disinfection cycles with Arc. Together, Arc and Arc Air offer a more comprehensive disinfection strategy for indoor spaces, allowing businesses, schools, government buildings, and other organizations to reopen safely — and continue safeguarding the health of their people in the post-pandemic world.
Indoor air quality has been and will continue to be an issue long after this current pandemic concludes. We know that Americans spend a startling 90% of their time indoors, where concentration of pollutants, including pathogens, can be up to 5 times higher than those outdoors. According to EPA estimates, poor indoor air quality affects up to 50% of commercial buildings in the country and results in over 125 million lost school days and 10 million lost work days each year. These obstacles notwithstanding, solutions like Arc Air that kill rather than merely capture aerosolized threats will continue to play a critical role in facilitating health and safety for all.
Study Lead: Richard L Wade PhD, MPH, Chief Scientist, R-Zero
Omega Environmental: indoor air quality specialist
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