From Virus to Protection #7: Distance -Receiving a Virus Through the Air
A blog series on SARS-CoV-2 (the virus that causes COVID-19) and how spread can be eliminated.
This blog series was inspired by the many questions people ask on this topic (see our FAQ links for more)
As distance decreases, risk increases (but that may not be a linear relationship). Virus particles can be concentrated into droplets or spread out in aerosol clouds. Droplets drop, and clouds spread out, linger, and dissipate.
As a refresher, here is what was presented earlier:
Infectious virus particles, perhaps millions of them are encased in other bodily fluids. Few of these can be seen with the naked eye, and most cannot.
The concentration of virus (viral load) you will be exposed to decreases significantly with distance generally. However, in enclosed spaces with inadequate ventilation, the smaller particles, which may be the most dangerous because of their quantity and the ease with which they enter the body (aerosols) can both linger and build up to levels that a person can be infected at significant distances. This is where it is most important for people to keep their bodily fluids to themselves.
Important: From a cough, a sneeze, from loud talking, shouting or screaming, the risk is much higher because:
- the amount of infectious bodily fluids projected can increase greatly,
- they are projected at a greater force, and can more easily penetrate poor quality face coverings,
- they are much more likely to infect those facing them,
- and they can travel much further than the ‘6-foot safe distance’ commonly recommended.
Common sense then says: the most effective protection method is to stay outside in the fresh air where a little breeze can keep the air clear. This is why so many outdoor restaurants have been moved outdoors so people can eat safely because they cannot wear respirators while eating.
An important consideration is the ventilation of rooms to dissipate and exhaust viral clouds quickly to prevent a build-up of aerosols. Some method recommendations made by experts around the world are to increase ventilation by upgrading HVAC equipment, open doors and windows or to add room air purifiers to combat build-ups.
With a little common sense, we can see that the size of the viral load a person receives would depend on three things:
- Their distance from the source,
- Whether they are wearing a face covering,
- the time of exposure (a build-up of viral load occurs from each inhale),
- the concentration of virus in the stream of bodily fluids being sent their way (including un-dissipated aerosols), and
- the concentration of aerosols in the environmental air they breathe (high levels of dissipated aerosols which have built up the room they are in because of poor ventilation.)
As the virus is passed our direction, we don’t want to receive it. To reduce the risk of receiving the virus into our bodies directly from droplets and aerosols we can employ protective devices. These can range from face coverings, face shields, goggles and protective hoods to full body suits with or without internal air purifiers or external purified air sources. The most important protection is a face covering.
"As the virus is passed our direction, we don’t want to receive it. To reduce the risk of receiving the virus into our bodies directly from droplets and aerosols we can employ protective devices. -The most important protection is a face covering."
Just a cheap face covering goes a long way in keeping bodily fluids to oneself. By now, it should be clear why (as common-sense dictates) everyone in an area where the virus is infecting people needs to wear a mask whenever they come into a situation where they might be exposed.
Disclaimer: We make no claim that these teachings are up-to-date. Researched by a scientist, they are current understanding, to the best of our knowledge. Consult medical professionals before making medical decisions for yourself or others, just to be sure. Be safe, be careful. SARS-CoV-2 (the virus that causes COVID-19) is a serious enemy that can kill.
The next blog discusses: Transfer -Infection by Picking Up a Virus off Contaminated Surfaces.