Windows not Windex

Science News: Though no one solution works for all places, public spaces need to focus on proper ventilation, air filtration, germicidal ultraviolet lights and air quality monitoring rather than rigorously disinfecting surfaces, say many scientists who cite evidence that the virus lingers in the air.

“This is what’s really frustrating,” says Jose-Luis Jimenez, an aerosol scientist at the University of Colorado Boulder. “We’ve wasted billions and billions of dollars on disinfecting, which doesn’t serve any purpose whatsoever, yet things like having a $50 filter in every classroom, we haven’t done.”

Similarly, in an excellent piece Derek Thompson writes:

Too many U.S. institutions throughout the pandemic have shown little interest in the act of learning while doing. They etched the conventional wisdoms of March 2020 into stone and clutched their stone-tablet commandments in the face of any evidence that would disprove them. Liberal readers might readily point to Republican governors who rejected masks and indoor restrictions even as their states faced outbreaks. But the criticism also applies to deep-blue areas. Los Angeles, for instance, closed its playgrounds and prohibited friends from going on beach walks, long after researchers knew that the coronavirus didn’t really spread outdoors. In the pandemic and beyond, this might be the fundamental crisis of American institutions: They specialize in the performance of bureaucratic competence rather than the act of actually being competent.

The CDC’s announcement should be curtains for theatrical deep cleanings. But until companies, transit authorities, retailers, and magazines embrace the value of scientific discovery and the joy of learning new things, the show, and the soap, will go on.

Fortunately, there has been some recent learning. The Indian government now advises:

Aerosols could be carried in the air for up to 10 metres and improving the ventilation of indoor spaces would reduce transmission…“Ventilation can decrease the risk of transmission from one infected person to the other. Just as smells can be diluted from the air through opening windows and doors and using exhaust systems, ventilating spaces with improved directional air flow decreases the accumulated viral land in the air, reducing the risk of transmission. Ventilation is a community defense that protects all of us at home or at work,” it stated.

One thing which puzzled me even before the pandemic was the lack of interest in UVC even though there is credible evidence that it reduces hard to kill superbugs.

The large study, published in The Lancet, finds machines that emit the UV light can cut transmission of four major super bugs by a cumulative 30 percent. The finding is specific to patients who stay overnight in a room where someone with a known positive culture or infection of a drug-resistant organism had previously been treated.

“Some of these germs can live in the environment so long that even after a patient with the organism has left the room and it has been cleaned, the next patient in the room could potentially be exposed,” said Dr. Deverick J. Anderson, MD, an infectious disease specialist at Duke and lead investigator of the study. “Infections from one of these bugs are tough to treat and can be truly debilitating for a patient.”

The attentive reader will note that this also implies airborne transmission.

Even the FDA is moderately supportive of UVC:

UVC radiation is a known disinfectant for air, water, and nonporous surfaces. UVC radiation has effectively been used for decades to reduce the spread of bacteria, such as tuberculosis. For this reason, UVC lamps are often called “germicidal” lamps.

UVC radiation has been shown to destroy the outer protein coating of the SARS-Coronavirus, which is a different virus from the current SARS-CoV-2 virus. The destruction ultimately leads to inactivation of the virus. (see Far-UVC light (222 nm) efficiently and safely inactivates airborne human coronavirusesExternal Link Disclaimer). UVC radiation may also be effective in inactivating the SARS-CoV-2 virus, which is the virus that causes the Coronavirus Disease 2019 (COVID-19).

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