COVID-19: The Spread

Originally posted 4 June 2020 | Updated 1 Sep 2020

The experts call for ‘social distancing’ of between three and six feet between persons.

Can we talk?

Do you know why droplets are called droplets? The word formed by the first four letters is your clue: they are heavier than air. Gravity causes them to drop. Down. Not up.

The dire warnings cause us to think that beyond those droplets there is little to no risk of inhaling the communist Chinese virus (CCV).

Odor producing aerosols are generally, almost always, invisible to the naked eye. Examples of invisible aerosols are perfumes, the odor of dead animals, fragrant flowers, and cigarette smoke.

Before you correct me through a comment below, allow me to go a little farther.

Is cigarette smoke visible? Yes, close to the smoker. But, it’s also invisible, at least the aerosols that carry the odor of a smoker invisibly through the air. The odor you smell at a distance is from the invisible aerosols exhaled by the smoker.

Although I am an ex-smoker who quit a bad habit back in 1975, I often smell the odor of exhaled smoke between vehicles on the road and on city streets, as much as a block distant from the smoker.

What’s the point? The coronavirus does not require large, visible droplets from an infected person to sicken you. You could inhale a number of coronaviruses from beyond talking distance.

In The News

When the pandemic began, [mechanical engineer Shannon Horn] explained, scientists weren’t sure how the novel coronavirus even spread. Many suspected that it jumped from person to person via surfaces like door handles or tabletops. But a growing body of evidence suggests that the pathogen can also fly—or, at least, float through the air inside the tiny droplets of fluid, or aerosols, that people expel when they breathe or talk.

Consulting Specifying Engineer Magazine 1 Sep 2020 | Why better ventilation is key to limiting COVID-19 spread

CDC finds for 6% of COVID-19 deaths, the virus was the only cause mentioned. For all others there was an average of 2.6 comorbidities

Table 3 shows the types of health conditions and contributing causes mentioned in conjunction with deaths involving coronavirus disease 2019 (COVID-19). For 6% of the deaths, COVID-19 was the only cause mentioned. For deaths with conditions or causes in addition to COVID-19, on average, there were 2.6 additional conditions or causes per death. The number of deaths with each condition or cause is shown for all deaths and by age groups. 

CDC 26 Aug 2020 | Weekly Updates by Select Demographic and Geographic Characteristics

John White
Rockwall, Texas

Published by John White

A lifetime (over 50 years) of experiences with automation and control systems ranging from aerospace navigation, radar, and ordinance delivery systems to the world's first robotic drilling machine for the oil patch, to process-control systems, energy management systems and general problem-solving. At present, my focus is on self-funding HVAC retrofit projects and indoor air quality with a view to preventing infections from airborne pathogens.

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