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A universal virus-killer?

By Vox

Discover the historic and potential future uses of UV light in infectious disease prevention in this intriguing episode of "Unexplainable," featuring insights from speakers Noam Hassenfeld, Dylan Matthews, David Brenner, and Jose-Luis Jimenez. The episode delves into the pioneering experiments of William and Mildred Wells from the 1930s, whose work with UV irradiation chambers in classrooms paved the path for contemporary research in combatting airborne pathogens. With the COVID-19 pandemic fueling a renewed interest in air disinfection, this timely discussion explores the viability and safety of far-UVC light as a modern-day mitigation strategy.

The narrative weaves through the complexities and debates surrounding the use of UV light against viruses, touching on both the promising advantages of this technology and the potential risks, such as ozone production and air quality concerns. The presence of Kim Moss brings additional depth to the conversation, while the speakers collectively emphasize the importance of further research and large-scale studies. This episode of "Unexplainable" invites listeners to consider the evolving science behind disease control and the critical examination of novel methods in our ongoing fight against airborne illnesses.

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A universal virus-killer?

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A universal virus-killer?

1-Page Summary

The Experiment of William and Mildred Wells in the 1930s

In the 1930s, William and Mildred Wells conduct experiments using ultraviolet (UV) light to combat airborne infectious diseases in classrooms. They create irradiation chambers equipped with UV rays with the hypothesis that these could eliminate pathogens lingering in the air after being expelled by an infected person. Their work shows a reduction in the transmission of airborne diseases like measles, effectively establishing a foundation for future environment-based disease control research.

Renewed Interest in Air Disinfection

The COVID-19 pandemic brings a resurgence of interest in air disinfection, specifically the potential of ultraviolet (UV) light, with scientists investigating the use of far-UVC light for this purpose. Kim Moss and David Brenner find that far-UVC light, particularly at 222 nanometers, kills pathogens including viruses effectively and may be safe for human exposure. Dylan Matthews compares its efficacy favorably to traditional ventilation systems. However, concerns arise about the production of ozone from far-UVC light, which can be harmful and lead to indoor air pollution when it reacts with volatile organic compounds. Debates ensue on the risks and mitigation strategies for ozone production, with experts like Jose-Luis Jimenez calling for careful implementation in high-risk settings to avoid indiscriminate use due to concerns about air quality.

Need for Further Research

The ongoing debate underscores the need for further research to assess the safety and effectiveness of using low wavelength UV light for air disinfection. Large-scale studies are required to provide direct evidence and address concerns about the impact on air quality and human health. Early small-scale studies report no significant discomfort in eye health, and extended tests on mice have not shown detrimental effects, but challenges like increased air pollution deaths and ozone production need empirical data. Trials in controlled environments such as oil rigs, where health and air quality can be closely monitored, are proposed. Participants would need to be fully informed of the risks, especially possible exposure to contaminants like ozone. Matthews emphasizes the necessity for more data on possible side effects and the importance of evaluating the cost-effectiveness of UV light use in pandemic control compared to its benefits, suggesting a pressing demand for detailed insights into its economic and health impacts.

1-Page Summary

Additional Materials

Clarifications

  • Irradiation chambers are enclosed spaces equipped with UV rays used to disinfect air by exposing it to ultraviolet light. In the context of the Wells' experiment, these chambers were designed to eliminate pathogens in the air, such as those causing airborne diseases like measles. The UV light in these chambers targets and deactivates harmful microorganisms present in the air, reducing the transmission of infectious diseases. This method laid the groundwork for future research on using UV light for air disinfection in controlled environments.
  • Far-UVC light is a type of ultraviolet light with a wavelength of 222 nanometers. It has been found to effectively kill pathogens, including viruses, while potentially being safe for human exposure. However, concerns exist regarding the production of ozone when far-UVC light reacts with volatile organic compounds, which can lead to indoor air pollution. Researchers are exploring the use of far-UVC light for air disinfection, balancing its effectiveness against potential risks like ozone production.
  • Ozone production from far-UVC light can occur when the light interacts with volatile organic compounds in the air, leading to the creation of ozone molecules. Ozone, when present in indoor environments, can contribute to air pollution and pose health risks, especially when produced in significant amounts. Experts are concerned about the potential negative effects of ozone on air quality and human health, prompting discussions on how to mitigate these risks while harnessing the benefits of far-UVC light for air disinfection.
  • Mitigation strategies for ozone production involve implementing measures to reduce the formation of ozone when using far-UVC light for air disinfection. This can include optimizing the design of UV light systems to minimize ozone generation, ensuring proper ventilation to disperse ozone, and monitoring ozone levels to maintain indoor air quality standards. Additionally, using air purification technologies that can neutralize ozone and implementing protocols for safe operation and maintenance of UV light systems are essential mitigation strategies.
  • The economic and health impacts of UV light use in air disinfection involve assessing the costs of implementing UV technology against the benefits of reduced disease transmission. This evaluation includes considerations such as initial setup costs, maintenance expenses, and potential health benefits from improved air quality. Understanding these impacts helps decision-makers determine the feasibility and effectiveness of incorporating UV light into disease control strategies.

Counterarguments

  • The effectiveness of UV light in reducing airborne diseases in classrooms during the Wells' experiments may not directly translate to modern settings due to changes in building design, ventilation standards, and the nature of pathogens.
  • The reduction in disease transmission observed by the Wells could be influenced by other factors such as natural immunity or concurrent public health interventions, not solely UV light.
  • The safety of far-UVC light at 222 nanometers for human exposure, despite early studies, remains uncertain until long-term effects are thoroughly researched.
  • The comparison of far-UVC light's efficacy to traditional ventilation systems may not account for the benefits of ventilation beyond pathogen control, such as reducing CO2 levels and other indoor pollutants.
  • Concerns about ozone production from far-UVC light may be valid, and the potential health risks could outweigh the benefits of using UV light for air disinfection if not properly managed.
  • The call for large-scale studies to provide direct evidence is important, but such studies can be costly, time-consuming, and may face ethical considerations regarding the exposure of participants to potential risks.
  • The proposal for trials in controlled environments like oil rigs may not be representative of typical public settings where UV light disinfection would be applied, limiting the generalizability of the results.
  • The reliance on animal studies, such as those on mice, to infer safety for humans may not always accurately predict human health outcomes due to biological differences.
  • The emphasis on the need for more data on side effects and cost-effectiveness is crucial, but it may delay the implementation of potentially beneficial technologies in urgent situations like a pandemic.
  • The economic and health impacts of UV light use in pandemic control must be balanced against other interventions that may be more immediately feasible and less technologically complex.

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A universal virus-killer?

The Experiment of William and Mildred Wells in the 1930s

In the 1930s, William and Mildred Wells conducted pioneering experiments to combat airborne infectious diseases in school classrooms using ultraviolet (UV) light.

Using UV light to kill airborne pathogens in school classrooms

The Wellses theorized that infectious diseases could linger in the air long after being expelled from an infected person and sought a way to eliminate these pathogens. They engineered a method to purify the air by placing irradiation chambers equipped with UV rays in classrooms.

Evidence it reduced measles transmission

Their innovative approach provided evidence ...

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The Experiment of William and Mildred Wells in the 1930s

Additional Materials

Clarifications

  • UV light can be used to kill pathogens like viruses and bacteria by damaging their genetic material. When UV light is used in irradiation chambers, it can effectively sterilize the air and surfaces in a room. This method is particularly useful for combating airborne diseases as it can target pathogens suspended in the air. The effectiveness of UV light in reducing the transmission of diseases like measles has been demonstrated through research and practical applications.
  • Irradiation chambers are enclosed spaces where UV rays are emitted to kill pathogens in the air. UV light damages the genetic material of microorganisms, rendering them unable to replicate. These chambers are designed to ensure that the UV light effectively reaches all areas within the space. The process helps in purifying the air by eliminating harmful airborne pathogens.
  • UV light has germicidal properties that can destroy the DNA of pathogens like viruses and bacteria, rendering them unable to replicate and cause infections. When UV light is used to irradiate the air in a space like a classroom, it can kill airborne pathogens, including those responsible for diseases like measles. By reducing the concentration of infectious agents in the air, the likelihood of transmission from person to person is decreased, thus helpin ...

Counterarguments

  • The effectiveness of UV light in reducing airborne pathogens may vary depending on the intensity and wavelength of the UV light, as well as the duration of exposure, which could affect the generalizability of the Wellses' findings.
  • UV light can be harmful to human skin and eyes, raising concerns about the safety of using UV irradiation in occupied spaces like classrooms.
  • The Wellses' experiments were conducted in the 1930s, and the technology and understanding of infectious diseases have evolved since then, possibly limiting the applicability of their findings to modern settings.
  • The use of UV light as a disinfection method does not address the source of infection and may not be as effective as strategies aimed at preventing the spread of pathogens at the source, such as vaccination or improved hygiene practices.
  • The cost and maintenance of UV irradiation systems could be prohibitive for widespread implementation in schools, especially in resource-limited settings. ...

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A universal virus-killer?

Renewed Interest in Air Disinfection

Since the COVID-19 pandemic highlighted aerosol transmission of diseases, there is a renewed emphasis on air disinfection methods, including UV irradiation.

Using far-UVC light to kill viruses

Scientists are currently experimenting with far-UVC light as a method for air disinfection.

Evidence it effectively kills viruses in air

Kim Moss states that far-UVC light, specifically at a wavelength of 222 nanometers, is highly effective at eliminating a range of pathogens including viruses, bacteria, mold, and allergens. Medical physicist David Brenner has been at the forefront of this research, indicating that this type of UV light may be safe for human exposure while effectively killing microorganisms. Research has shown that low doses of far-UVC light can kill 99.9% of the coronavirus and is approximately 95% effective against swine flu.

Dylan Matthews notes that far-UVC light could potentially reduce the spread of respiratory illnesses better than traditional ventilation systems due to its ability to purify the air at a rate comparable to numerous air changes per hour.

Debate around potential downsides like ozone production

However, the use of far-UVC light is not without its potential drawbacks. One concern is that its interaction with oxygen may produce ozone, which can be detrimental when inhaled. Ozone can also react with volatile organic compounds (VOCs) such as those emitted during cooking or from personal care products, potentially leading to indoor ...

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Renewed Interest in Air Disinfection

Additional Materials

Clarifications

  • Far-UVC light is a type of ultraviolet light with a wavelength of 222 nanometers. It has shown effectiveness in killing various pathogens like viruses and bacteria. Far-UVC light is being researched for its potential to disinfect air without harming human skin or eyes. Its ability to kill microorganisms makes it a promising tool for reducing the spread of diseases in indoor environments.
  • Ozone production from far-UVC light can be a concern due to its potential negative effects on indoor air quality. When far-UVC light interacts with oxygen, it can lead to the creation of ozone, which can be harmful when inhaled. Ozone may also react with volatile organic compounds (VOCs) present in indoor environments, potentially contributing to indoor air pollution. This issue has sparked debate among experts regarding the risks and appropriate usage of far-UVC light for air disinfection.
  • Debate among chemists regarding ozone production and its effects stems from concerns about the potential health risks associated with ozone exposure indoors. Some argue that the risks of ozone production might be overstated and could be managed through various methods, such as absorption into room furnishings. However, others are more cautious, highlighting the potential for ozone to react with volatile organic compounds (VOCs) and create indoor air pollution. The discussion revolves around balancing the benefits of far-UVC light for air disinfection with the ...

Counterarguments

  • Far-UVC light's effectiveness may vary depending on the type of virus or pathogen, and some microorganisms may be more resistant than others.
  • The safety of far-UVC light for human exposure, while promising, may require more extensive long-term studies to fully understand potential risks.
  • The comparison of far-UVC light to traditional ventilation systems may not account for the benefits of fresh air exchange beyond pathogen removal, such as reducing CO2 levels and other indoor pollutants.
  • The mitigation strategies for ozone production, such as absorption by room furnishings, may not be effective in all settings or may introduce other risks, such as the release of other harmful compounds.
  • The recommendation to use far-UVC light only in high-risk settings may not consider the potential benefits of wider implementation in reducing overall disease transmission in the general population.
  • The focus on ozone production as a downside may overshadow other potential negative effects of UV ...

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A universal virus-killer?

Need for Further Research

The discussion highlights the necessity for comprehensive research to establish both the safety and effectiveness of using low wavelength UV light for air disinfection.

Large-scale studies to confirm safety and effectiveness

There is an urgency for direct evidence through large-scale studies that can confirm the safety and effectiveness of low wavelength UV light deployment, especially regarding its impact on air quality and human health. So far, ongoing smaller-scale studies, such as one in a classroom setting using a shorter wavelength UV light, have not reported any noticeable difference in eye comfort. Similarly, long-term experiments on mice exposed to lower wavelength UV light have shown no effects on skin or eyes, yet questions about the air remain.

One concern raised by Jimenez involves the possibility of increased air pollution deaths due to low wavelength UV usage, a hypothesis that awaits empirical data from a large-scale application. A proposed method for acquiring such data is piloting the technology on an oil rig, an environment ideal for controlled testing due to isolation, staggered shifts, and the capability for regular health and air quality monitoring. Any such pilot program would require informed consent from participants, who must be aware ...

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Need for Further Research

Additional Materials

Clarifications

  • Low wavelength UV light is being studied for its potential to disinfect air, but its impact on air quality and human health is not yet fully understood. Research is ongoing to determine if using low wavelength UV light for air disinfection is safe and effective, especially in terms of its effects on air quality and human health. Concerns include the potential for increased air pollution deaths and the need for large-scale studies to confirm safety and effectiveness. Further research is needed to assess any potential risks and benefits associated with the use of low wavelength UV light for air disinfection.
  • Concerns about increased air pollution deaths due to low wavelength UV usage stem from the potential of UV light interacting with air pollutants like ozone, which could lead to the formation of harmful byproducts. This hypothesis suggests that the use of low wavelength UV light for air disinfection might inadvertently create compounds that could worsen air quality and pose risks to human health. The impact of these interactions on overall air quality and human health needs to be thoroughly studied through large-scale research to assess the safety and effectiveness of this technology. The concern is that without proper understanding and mitigation strategies, the deployment of low wavelength UV light could have unintended consequences on air quality and public health.
  • Piloting low wavelength UV technology on an oil rig involves testing the effectiveness and safety of using UV light for air disinfection in a controlled environment. The unique conditions of an oil rig, such as isolation, staggered shifts, and the ability to monitor health and air quality regularly, make it an ideal setting for such testing. This pilot program would require participants' informed consent and aims to gather empirical data on the impact of UV light on air quality and human health. The goal is to assess the feasibility of using UV technology in real-world scenarios like oil rigs before considering broader implementation.
  • In UV light pilot programs, informed consent from participants is crucial to ensure they understand the potential risks involved in the study. This consent ensures that participants are fully aware of the purpose, procedures, and possible outcomes of the research before agreeing to take part. It is a standard ethical practice in research to protect the rights and well-being of individuals involved in experimental studies. Informed consent allows participants to make voluntary and informed decisions about their participation in the study.
  • Low wavelength UV light is being considered for air disinfection, but conc ...

Counterarguments

  • The urgency for large-scale studies might be overstated if existing data from smaller studies and other applications of UV light suggest a reasonable level of safety and efficacy.
  • The lack of noticeable effects in smaller-scale studies and long-term experiments on mice might not warrant the level of concern suggested, as these findings could indicate that low wavelength UV light is indeed safe for use in air disinfection.
  • The concern about increased air pollution deaths could be mitigated by existing knowledge of UV light interactions with air contaminants, and the risk might be lower than suggested if proper mitigation strategies are employed.
  • The proposal to pilot the technology on an oil rig might not be the most representative environment for the general population, and results from such a study might not be generalizable.
  • The demand for more verifiable information before widespread implementation could delay the use of a potentially beneficial technology in urgent situations, such as duri ...

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