Ultraviolet light to reduce the risk of airborne viral transmission in occupied locations
Dr. David Brenner
Monday, October 11, 2021
Zoom Event page*:
For the recording of the presentation, go to the
Most of us have heard of UVA and UVB, two ranges of ultraviolet light waves that should be filtered by sunscreen lotions or sprays to protect the human skin from sunburn. But fewer are familiar with UVC and UVV ranges at the far end of ultraviolet light frequencies emitted by the sun.
UVV has the shortest wavelengths. It interacts with oxygen molecules, creating ozone. Ozone is highly reactive. In elevated concentrations, it is deadly to any living organism. If inhaled, it can cause lung cancer! Fortunately, oxygen is abundant enough in the stratosphere for UVV energy to be depleted before it reaches the troposphere, let alone Earth’s surface.
UVC interacts and gets diffused by a variety of molecules in the atmosphere. UVC also does not reach lower elevations.
Besides the ocean, the spherical layering of the atmosphere is the most important natural life-support system of our planet. The highest concentration of ozone occurs at about 15 miles above the surface, which has become known as the ozone layer. Here, most UVB was interacting with ozone. Relatively little UVB reached us before the middle of last century when we started to release massive amounts of chlorine-containing chemicals such as chlorofluorocarbons (CFCs) into the air.
Chlorinated compounds lighter than air, escaping from air-conditioner refrigerants, aerosol sprays and similar products, disrupted the natural ozone balance in the stratosphere by depleting the ozone layer. UVB causes non-melanoma skin cancer and plays a major role in malignant melanoma development. It also damages plants and marine life, reducing revenues in agriculture and fisheries.
UVA is diffused and reflected to some extent by water vapor, ice crystals and other particles in the atmosphere, but its proportion in the sunlight that reaches the surface has not been altered substantially by human impacts.
Ultraviolet light has been used for decades to disinfect objects; rooms; and heating, ventilation and air conditioning (HVAC) systems. UVC is particularly suitable for that purpose because it disrupts the genetic code of microbes and viruses. Around 222 nm, it barely penetrates the outermost layers of human skin.
CAUTION — During the COVID-19 pandemic many vendors started offering ultraviolet lamp devices to consumers for use at home. Presently there is no certification standard for the safety and effectiveness of such devices. Even when used properly, invisible UV rays may unexpectedly get reflected by a mirror, metal or glass object and focus a beam at an eye. Users risk inadvertent, delayed and permanent harm, including severe burns or eye injury to themselves, children and pets. This has prompted the National Electrical Manufacturers Association (NEEMA), the American Lighting Association and the United Laboratories (UL) to issue a Warning: Consumers currently have no assurance against the risks of UVC over-exposure from consumer oriented UVC devices that do not provide proper containment of the UVC emissions. When used improperly, these types of devices may present an undue health risk. If you have already purchased such a device or believe you must buy one, watch this 7-minute video and watch Dr. Brenners presentation to learn about all the research that has already gone into discovery and verification of the best wavelengths, energy levels, and durations of exposure needed to obtain the desired outcomes and what further must be done to develop safe, reliable and affordable technologies to deliver the expected results at scale.
Dr. Brenner directs the Center for Radiological Research, which is now more than 100 years old. He started his career in theoretical physics — applying quantum mechanics to radiation therapy.
He focuses his work on special UVC lamps for interior spaces to destroy viruses without human injury. Some experts have noted that present prices of such lamps is about $500 each; a cost that would likely decrease if the lamps were mass produced.
His presentation is an opportunity to stimulate regional interest in developing advanced manufacturing technologies to rapidly lower production costs to about $15 per lamp. Market demand for 222 nm lighting devices could reach $24.2 billion by 2025, according to one estimate, with prospects of major R&D funding from government and private companies.
Dr. Brenner thinks, “the market is many-fold: Initially for hospitals, in operating rooms for irradiating above incisions during surgery to reduce surgical site infection rates. For public locations such as schools, hospitals, doctors offices, airports, airplanes and the food preparation industry, to reduce airborne transmission of viruses including influenza and measles, and bacteria such as TB.”
* Virtual event hosted by the Foundation for Global Sustainability (FGS).
FGS facilitates educational events to inform the public and foster better understanding of complex environmental, social and economic issues that impact the resilience of communities and the natural life support systems of planet Earth. Views and opinions expressed by event organizers and participants do not necessarily reflect the views of FGS. FGS neither endorses any product or service mentioned nor warrants for accuracy, completeness or usability of the information.