Six feet is the wrong model

A friend sent me this paper on Arxiv.org – “A physicist view of the airborne infection” by Luis A. Anchordoqui and Eugene M. Chudnovsky. They used SimScale to model airflow in an office and included a couple of nice visualizations:

The paper is quite concise and worth your time, just under 2.5 pages. Short version? Six feet ain’t enough and your office is a Petri dish.

From the physics point of view, we cannot find a good justification for a stationary 6-feet separation in a situation when people spend long time together in a room. Droplets containing the virus move in the air via convection. The convection pattern in a room can be very complex; see Fig. 1. It depends on the location of air conditioners, radiators, windows, and all items in the room, as well as on people producing vortices by moving around. The existing vortices in the air can make a location far away from the source of droplets more dangerous than the location 6 feet away. This applies to meeting rooms, office spaces, supermarkets, department stores, etc. The airflow pattern should be studied for all such facilities to avoid the spread of infection to large distances from a single infected person. The safest rooms must be those equipped with the air sucking ventilator at the top, like hospital surgery rooms

Luis A. Anchordoqui and Eugene M. Chudnovsky

https://arxiv.org/pdf/2003.13689.pdf?referringSource=articleShare

What’s the Evidence on Face Masks? What You Heard Was Probably Wrong

Although most of the studies in the Cochrane Review were on medical workers in a hospital setting, one study followed community transmission of SARS in Beijing. It found that consistently wearing a mask in public was associated with a 70% reduction in risk of catching SARS. Additionally, the authors of the paper noted that most people in the community wore simple surgical masks, not N95 respirators.

What’s the Evidence on Face Masks? What You Heard Was Probably Wrong

Yep, early advice was wrong – get masks and wear them. Can’t find them in stock? Sites are popping up with instructions on how to DIY: