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COVID-19 -

In 2020, people became acutely aware of the dangers posed by invisible threats like viruses and bacteria. The COVID-19 pandemic reminded us of the importance of understanding and combating these pathogens to avoid widespread illness and fatalities.

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Ultraviolet light -

Despite being known for over a century, ultraviolet (UV) light remains underutilized as a disinfectant. UV light has proven its ability to kill pathogens, but its regular integration into everyday tools and spaces is still inconsistent.

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The electromagnetic spectrum -

The electromagnetic spectrum is the range of all types of radiation that exists, from low-energy radio waves to high-energy gamma rays. It includes visible light, microwaves, X-rays, and more, each with different wavelengths and frequencies. This radiation is measured in nanometers.

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Visible light -

On the electromagnetic spectrum, visible light has a measurement of between approximately 380 and 780 nanometers.

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UV on the spectrum -

Ultraviolet light occupies a small but potent part of the electromagnetic spectrum, between 100 and approximately 400 nanometers. There are three different types of UV light: UV-A, UV-B, and UV-C, all occurring at different wavelengths.

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The sun -

Most of the light that reaches the Earth from the sun consists of UV-A and UV-B rays, but UV-C is particularly useful in disinfection and has been studied for its pathogen-killing capabilities.

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UV-A and UV-B -

UV-A and UV-B rays are harmful to humans. They cause skin and eye damage, including cancer, by damaging DNA in our cells. This makes these types of UV light unsuitable for direct exposure to humans.

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A double-edged sword -

Ironically, the same DNA-damaging properties that make UV light dangerous to humans are what also make it effective against viruses and bacteria. It disrupts their replication process, making it an effective tool for infection control.

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Early discoveries -

Researchers discovered the germicidal properties of UV-C light in the late 19th century. This led to decades of experimentation with using low-wavelength UV light as a disinfectant, specifically for killing bacteria and viruses. UV-C became a key area of research in public health.

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Classrooms -

In the 1940s, UV irradiation chambers were installed in classrooms to combat airborne viruses. The UV light was projected safely into the air above the students, preventing direct exposure.

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Results -

Studies conducted in classrooms with UV irradiation showed that fewer than 15% of students were infected with measles, compared to over 55% in classrooms without UV light. UV-C clearly had the potential to be a powerful tool for controlling the spread of airborne viruses.

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Tuberculosis -

Subsequent studies tested UV light’s effectiveness against tuberculosis. Using rodents, researchers found that irradiated air prevented the animals from contracting the disease.

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Installation -

While UV-C light is effective against pathogens and operates at a low wavelength, it still has the potential to harm humans. It also has to be installed carefully using an expensive process known as upper room UV.

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Hospitals - Upper room UV systems are still used today, particularly in hospitals where infection control is critical. Paired with proper ventilation, these systems reduce the spread of pathogens in the air.

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Limitation -

Although UV lights are effective, having them installed at the top of a room does very little in preventing the spread of germs between people on the ground.

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The search for safer solutions -

Recent research has focused on finding safer ways to use UV light in public spaces. Scientists have been studying how to maximize UV-C's ability to kill bacteria and viruses while minimizing the harm to human health. This has led to the development of a safer form of UV-C called far-UV, which sits at about 222 nanometers on the spectrum.

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Far-UV -

Far-UV is a form of UV-C with an even lower wavelength that cannot penetrate human skin deeply enough to cause damage. Research shows that far-UV light is effective at killing pathogens while being much safer for humans.

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Effectiveness -

Research conducted in 2020 during the COVID-19 pandemic demonstrated that far-UV could kill 99% of coronaviruses in controlled test chambers. This makes far-UV a highly effective tool in fighting airborne pathogens.

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Other bacteria -

Far-UV has also proven effective against other bacteria, such as the one responsible for staph infections. Studies have shown that far-UV can reduce these bacteria by as much as 98%.

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Risks -

Despite its effectiveness, there are still concerns about far-UV’s potential risks. Even though far-UV cannot cause cancer, UV light can cause chemical reactions in the air and produce ozone, which is harmful to breathe.

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Human health -

Exposure to high levels of ozone can lead to respiratory problems and exacerbate existing health conditions, although scientists are still uncertain as to how much ozone is actually produced by UV lights.

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Protective measures -

Far-UV is not intended to replace existing protective measures like HVAC systems or air filtration. Instead, it is designed to work in tandem with these systems, enhancing the overall ability to reduce the spread of pathogens.

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HVAC systems -

HVAC systems primarily control climate, with the secondary benefit of helping reduce the viral load in the air. While they don’t eliminate all pathogens, they are an essential part of maintaining air quality.

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Filtration -

Filtration systems help remove inorganic pollutants like smog and wildfire smoke, but far-UV is unmatched in its ability to eradicate living pathogens in the air. Combining these technologies would certainly offer a more comprehensive approach to improving air quality.

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Costs and benefits -

Experts warn against rushing to install far-UV lights in all settings without first considering the costs versus the benefits. While it may be invaluable in high-risk environments like hospitals, it may be costly or unnecessary in less hazardous places.

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Potential future -

It may take time before far-UV is widely adopted in public spaces. Researchers and public health experts emphasize that while far-UV has great potential, its role in everyday environments must be carefully considered to ensure safety.

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Damages -

It’s also important to remember that UV light, no matter where it lies on the spectrum, can be damaging to non-living things as well. Ultraviolet light breaks down chemical bonds, which could cause unforeseen repair costs for computers, appliances, paint on walls, and even artwork.

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Pandemics -

Experts agree that another future pandemic is more a matter of "when" than "if." As a result, having a variety of tools (including far-UV technology) will be critical for managing future outbreaks.

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Caution -

While far-UV is promising, public health experts caution against overreliance on any single technology as a "miracle cure." Disease prevention requires a multi-layered approach, combining far-UV with other measures like vaccines, masks, and disinfectants.

Sources: (Vox) (Healthline) (Scientific American) (National Institutes of Health) (Britannica) (Nature)

See also: Destinations with the highest UV levels

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