[kellyhound]

1 August 2023. Indoor airflow patterns and the spreading of respiratory air were studied using the large-eddy simulation (LES) computational fluid dynamics (CFD) approach. A large model room with mixing ventilation was investigated.

The model setup was motivated by super-spreading of the SARS-CoV-2 virus with a particular focus on a known choir practice setup where one singer infected all the other choir members.

The room was heated with radiators at two opposite walls in the cold winter time. The singers produced further heat generating buoyancy in the room.

The Reynolds number of the inflow air jets was set to RE=2750, corresponding to an air-changes-per-hour (ACH) value of approximately 3.5. The CFD solver was first validated after which a thorough grid convergence study was performed for the full numerical model room with heat sources.

The simulations were then executed over a time of
T=20 min to account for slightly more than one air change timescale for three model cases: (1) full setup with heat sources (radiators+singers) in the winter scenario, (2) setup without radiators in a summer scenario, and (3) theoretical setup without buoyancy (uniform temperature).

The COVID-19 pandemic has raised the general level of awareness on the indoor air quality due to the transmission of the SARS-CoV-2 virus as small airborne particles i.e. aerosols [1], [2], [3].

In fact, several key international organizations, such as the World Health Organization (WHO) and the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), mention the improvement of indoor air quality via ventilation and air filtration as major mitigation measures for virus transmission.



Meaning one infected person can contaminate an entire group under the right circumstances which are: a room humidity of 40% or lower like in late fall, winter and early spring and with heating on and windows more or less closed and the person speaking/singing loudly. This was already known during the Spanish flu but during the corona pandemic largely neglected especially in School classrooms, churches, bars, indoor sports events etc.
More:https://www.sciencedirect.com/scienc...60132323004894

[b0g]

The lower the room humidity, the less a virus in aerosol (a water particle) can survive, as it ll be killed by sunrays or drought.
That lower end of the spectrum is not featured in this setup.

Moreover Covid virus strains are now endemic,
unless you were living in a remote cave or deep under a large stone.

KH, maybe do a study on excess deaths?

[houseoftechno]

Everybody and everything not only lives in germ soup, but we are germ soup:

PLoS Biol. 2016 Aug; 14(8): e1002533.; Published online 2016 Aug 19. doi: 10.1371/journal.pbio.1002533; PMCID: PMC4991899; PMID: 27541692; Revised Estimates for the Number of Human and Bacteria Cells in the Body, Ron Sender et al; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4991899/

...the typical adult human body consists of about 30 trillion human cells and about 38 trillion bacteria.