Friday, July 10, 2020

Aerosols

Presently a paper stirs up the minds. Its title: "It is Time to Address Airborne Transmission of COVID-19" by Lidia Morawska and Donald K. Milton of the Queensland University of Technology.

Red Baron thought everything had already been said or written about the subject. In Germany, the Robert-Koch-Institute (RKI) in the current version of its coronavirus profile, refers clearly to infection through aerosols, "The main transmission pathway for SARS-CoV-2 is the respiratory uptake of virus-containing fluid particles that are produced when breathing, coughing, speaking and sneezing."

"Longer stays in 'small, poorly or unventilated rooms' may increase the risk of infection, even if the minimum distance of two meters is observed. Transmission in the fresh air, on the other hand, is 'rare.' The concentration of virus-laden particles in the air is quickly reduced by the wind."

Aerosols seem to transmit corona much more lustfully than we droplets (©SVLW)
As early as April 29, the Schweizerischer Verein für- Luft und Wasserhygiene (Swiss Association for Air and Water Hygiene) published an article: "Büroluft gibt Coronaviren Aufwind (Office air gives Coronaviruses upwinds)."

According to Lidia Morawska, the World Health Organization (WHO) is reluctant to update its advice. The paper published in the Oxford Academic Journal of Clinical Infectious Diseases recommends new safety measures, including increased indoor ventilation and the installation of high-grade air filters and UV lamps. At the same time, overcrowding in buildings and transport should be prevented.

"There is significant potential for inhalation exposure to viruses in microscopic respiratory droplets (microdroplets) at short to medium distances (up to several meters, or room-scale)," the authors continue.

"Handwashing 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 while breathing, speaking, coughing, or sneezing."

"Those droplets above five to ten micrometers - which is less than the width of a typical human hair - fall to the ground in seconds and within a meter or two."

"On the other hand, droplets under this size can become suspended in the air in what is called an 'aerosol,' remaining aloft for several hours and traveling up to tens of meters."

Cath Noakes, a professor of environmental engineering for buildings at the University of Leeds, who contributed to the paper, said, "COVID-19 doesn't spread in the air as easily as measles or tuberculosis, but is a threat nonetheless."

"COVID-19 is more likely to be 'opportunistically' airborne and therefore poses a risk to people who are in the same room for long periods," she added.

"The WHO says that there is insufficient evidence to prove that the aerosol/airborne transmission of SARS-CoV-2 is happening. We are arguing that there is insufficient proof that aerosol/airborne transmission does not occur," Professor Milton insisted.

In the meantime, the WHO has somehow reacted in a new report about Coronavirus, named SARS-CoV-2, "Airborne transmission of the virus can occur in health care settings where specific medical procedures, called aerosol-generating procedures, generate tiny droplets called aerosols. Some outbreak reports related to crowded indoor spaces have suggested the possibility of aerosol transmission, combined with droplet transmission, for example, during choir practice, in restaurants, or in fitness classes."

Why is the WHO so reluctant? According to conspiracists, this is Chinese influence. 

Due to the information spread by the RKI in Germany, Red Baron observes that people are well aware of aerosols and sit outdoors when taking their meals in a restaurant. I already mentioned that in Freiburg there is too little rain. Subsequently, the now extended surfaces for outside food service are well occupied in the evening. Still, restaurant owners moan that when keeping distances with the present disposition of tables even when filled to full capacity, they do not cover their costs of operation.

Will people go to indoor restaurants coming fall and winter? Will we see a second Corona wave, massive deaths of restaurants, or both?

What we know for sure. The virus is insidious.

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