239 Scientists: Health Experts Must Focus On Aerosols, Potential Airborne Coronavirus Transmission
Last edited Wed Jul 8, 2020, 07:46 PM - Edit history (1)
"Coronavirus can float in air and WHO and CDC should tell people that, experts say." By Maggie Fox, CNN, 1 hr. ago. July 6, 2020. - Excerpts, Ed:
Imagine a noisy, crowded bar. Music is pounding, and people are clustered close together, talking loudly or even shouting to be heard. If it's cold out, doors and windows are shut tight and the heat is on, or if it's hot out, everything is shut and the air conditioner is recirculating the air. This, in Donald Milton's opinion, is the perfect situation for spreading coronavirus. Not only could people pass the virus directly from one to another in the little droplets that we all spray to one degree or another when we talk, laugh or sing; but those little droplets also go up into the air where, Milton says, they can float around for at least some time. Milton, a professor of environmental health at the University of Maryland who studies how viruses are transmitted, has helped lead a group of 239 scientists who wrote an open letter to appeal for better recognition of the potential airborne transmission of coronavirus. Agencies seem to be afraid to talk about the airborne nature of the virus, Milton said. The current guidance from numerous international and national bodies focuses on hand washing, maintaining social distancing, and droplet precautions," he and colleagues wrote in the letter, published in the journal Clinical Infectious Diseases.
"Most public health organizations, including the World Health Organization, do not recognize airborne transmission except for aerosol-generating procedures performed in healthcare settings [such as intubation that can spew large quantities of the microscopic particles.] "Hand washing and social distancing are appropriate, but in our view, insufficient to provide protection from virus-carrying respiratory microdroplets released into the air by infected people," they added.."I guess we are hoping that WHO will come around and be more willing to acknowledge the important roles of aerosols, whether they want to call it airborne transmission or not." Milton studies the airborne transmission of viruses. He and and other similar experts have been discussing the potential airborne transmission of coronavirus since February. - "They don't want to talk about airborne transmission because that is going to make people afraid," he said. There's also an element of worry that if people think the virus is airborne, they'll stop doing other things they need to do to prevent transmission, such as washing hands, staying apart and cleaning surfaces.
"The best vaccine against fear is knowledge and empowering people to take care of themselves," Milton said. "I want them to understand to what extent washing their hands is important. Why wearing a mask is important is because it blocks the aerosols at their source, when it is easy to block them." It's harder to block aerosols once they are floating in the air, he said. The virus is carried on droplets that come out of people's mouths and noses, and the sizes of those droplets vary. Large droplets fall onto surfaces rapidly and can be picked up on fingers and carried to the eyes, nose or mouth. Smaller droplets can stay in the air longer, and can be inhaled more deeply into the lungs. "Studies have demonstrated beyond any reasonable doubt that viruses are released during exhalation, talking, and coughing in microdroplets small enough to remain aloft in air and pose a risk of exposure at distances beyond 1 to 2 meters (yards) from an infected individual," they added.
"For example, at typical indoor air velocities, a 5 nanometre droplet will travel tens of meters, much greater than the scale of a typical room, while settling from a height of 1.5 metres (about five feet) to the floor." What's not clearly understood is how important droplet size is to coronavirus transmission, Milton said. But studies show it's a factor, Milton added. "A lot of people crowded close together indoors where it is poorly ventilated -- that is what drives the pandemic,"..
- Advice to avoid coronavirus transmission: "I am very much concerned about the general public and schools and ventilation in school buildings and in dorms on college campuses and in bars and in churches and where people sing and where people congregate," he said. The group gives practical advice in its letter: * Provide sufficient and effective ventilation (supply clean outdoor air, minimize recirculating air) particularly in public buildings, workplace environments, schools, hospitals and age care homes. * Supplement general ventilation with airborne infection controls such as local exhaust, high efficiency air filtration, and germicidal ultraviolet lights. (These would be placed high up in the ceiling to avoid damage to people's eyes and skin) * Avoid overcrowding, particularly in public transport and public buildings. "For example, simple steps such as opening both doors and windows can dramatically increase air flow rates in many buildings."...
More, https://www.msn.com/en-us/health/health-news/coronavirus-can-float-in-air-and-who-and-cdc-should-tell-people-that-experts-say/ar-BB16on6e
- Related: "Scientists Say WHO Ignores The Risk That Coronavirus Floats In Air As Aerosol," Los Angeles Times, July 4, 2020. https://democraticunderground.com/1016260983
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