The coronavirus spread updated in real time

[_Jersey Girl]

And our school district just announced it is closing for a month. No reported cases.

I wish ours would do this!

Some colleges are switching to distance/remote learning. Meanwhile our K-12 students are still in the classroom and, God knows, jammed in the bus together.

wth

[_Icarus]

Instead of buying masks should we consider buying humidifiers? The science behind it seems pretty solid. Most respiratory diseases spread via tiny droplets when people sneeze or cough. This is the primary method in which coronavirus is passed on to others (touching the virus and then touching our mouths is secondary). The reason more people get sick during the winter is because of the dry air. When the air is more humid during the summer months it becomes heavier and those droplets tend to fall to the ground. With dry air, the droplets are more likely to be inhaled by others.

https://www.livescience.com/27533-flu-t ... nHDbgdrvUk

[_Some Schmo]

Right Wing heads are exploding all over the country right now. They've spent weeks claiming the coronavirus was a Democrat hoax, insisting it was just a mild flu that was overblown by a Liberal media hellbent on destroying Trump's precious economy. And now Trump bans all travel from Europe for 30 days. I wonder when they'll start accusing Trump of being part of the Deepstate intent on destroying his own Presidency.

One would think finding solid proof in your own life that the President has incompetently lied to the American people in a state of emergency would cause his fans to reconsider their allegiance, but one would be wrong. There's been plenty of proof of the moron's incompetence, but people in a cult have stopped thinking (assuming they ever did).

When granny dies of some respiratory complication, they'll blame the deep state (Trump will have had nothing to do with it in their addled minds, despite telling people they could continue to go to work with the virus). That idiot move has made sense to them in all other contexts; why not this one?

[_canpakes]

One would think finding solid proof in your own life that the President has incompetently lied to the American people in a state of emergency would cause his fans to reconsider their allegiance, but one would be wrong. There's been plenty of proof of the moron's incompetence, but people in a cult have stopped thinking (assuming they ever did).

When granny dies of some respiratory complication, they'll blame the deep state (Trump will have had nothing to do with it in their addled minds, despite telling people they could continue to go to work with the virus). That idiot move has made sense to them in all other contexts; why not this one?

Historians would do well to record this statement, for the benefit of generations 1000 years hence.

[_Icarus]

So a virus takes the world by storm in an election year that specifically targets older people and it appears men are more affected than women. If Biden's primary voting demographic was older males, the religious nuts on the Right would be calling the virus a message from God. However, the reality is opposite. Most men over the age of 60 support Trump by wide margins.

Depending on how things pan out, this could be something that gets me back to believing in God.

[_EAllusion]

Those long lines for voting, which are especially prominent in Democratic voting areas, concern me a great deal. Both from a public health and from an election legitimacy perspective.

[Alf'Omega]

Depending on how things pan out, this could be something that gets me back to believing in God.

The only thing that could tempt me to believe in a kind of divine intervention would be to watch Trump cough to death of the virus on live TV. That's the kind of reality TV this nation deserves, and it's far too poetically justified to not be the act of a very biblical god.

But Trump will probably survive this because there is no poetic justice god, and Trump was born with a horseshoe embedded in his lower colon.

[_Chap]

Instead of buying masks should we consider buying humidifiers? The science behind it seems pretty solid. Most respiratory diseases spread via tiny droplets when people sneeze or cough. This is the primary method in which coronavirus is passed on to others (touching the virus and then touching our mouths is secondary). The reason more people get sick during the winter is because of the dry air. When the air is more humid during the summer months it becomes heavier and those droplets tend to fall to the ground. With dry air, the droplets are more likely to be inhaled by others.

https://www.livescience.com/27533-flu-t ... nHDbgdrvUk

I have the sense that the people who wrote that article may not have got that quite right. That sentence "When the air is more humid during the summer months it becomes heavier and those droplets tend to fall to the ground" is both confused and confusing.

From the physical point of view, it's more like this:

1. In any given air conditions, a large drop of fluid released into still air will, other factors being kept constant, fall faster towards the ground than a small one.

2. Why?

(a) The maximum speed of a freely falling droplet will be the speed at which the upwards frictional force exerted on the droplet by the air through which the droplet moves is equal to the downwards force exerted on the droplet by earth's gravitational field (the 'weight') of the drop. (Hence the total force is zero, and the drop neither speeds up nor slows down: Newton's first law of motion, applied to motion in a straight line.)

(b) If you double the diameter of a drop, its volume (hence its mass, hence its weight) will increase by 2^3 = 8, whereas its surface area will only increase by 2^2=4. So the weight increases twice as fast as the friction, and the drop will reach a greater maximum falling speed.

3. If the air is already carrying all the water molecules it can manage (100% relative humidity, 'saturation'), any molecules of water that escape from the surface of the drop will be replaced by other water molecules entering the drop from the surrounding air. So a big drop stays big, and falls fast.

4. But if the air is carrying few water molecules, (low relative humidity), molecules of water that escape from the surface of the drop will NOT be replaced by other water molecules entering the drop from the surrounding air. So a big drop stays big, and falls more slowly. If it gets small enough, its falling speed will be so small that it just gets moved around by air currents, and is unlikely to reach the ground in any reasonable time.

5. What's this got to do with infection? Well, if I sneeze out big drops of water loaded with virus and relative humidity is high, they will not shrink, and will hit the ground quite soon, with less chance of passing infection to someone. But if humidity is low, drops that start off large may shrink quickly enough so that they become small and hang about in the air long enough for someone else to breath them in, together with the viruses they carry.

So ... low humidity raises the chance that the virus will be transmitted by droplets.

For a big dose of relevant science, see:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6364647/

[_EAllusion]

I know you are being tongue in cheek Icarus, but the prospect of lots of old people (and even an alarming number of not old people) getting extremely ill and possibly dying is too real and immediate to joke about celebrating in my opinion.

[Guest]

Chap, thanks for that explanation. It makes perfect sense, that small droplets would necessarily fall slower than large droplets, along with anything enclosed within them. But, if the droplet evaporates completely before hitting the ground, due to warmer, less saturated air, leaving just the dry viral particles floating in the air, how does that effect the viral particles? Does becoming completely dry benefit or harm the viral particle, thus making it more or less infectious? I would guess that would vary according to the type of virus. Does anyone know in the case of the new corona virus? Also, as you well know, humid air (contrary to popular understanding) is less dense and therefore weighs less than an equal volume of dry air, and would tend to rise in relation to dryer air surrounding it at an equal temperature and pressure. This could be yet another reason why the virus particles would tend to sink more slowly as the droplets containing them evaporate, leaving the air immediately surrounding them slightly less dense than before, and with a slight tendency to rise.

ETA: And what about the density of the viral particle itself? I imagine it is probably denser than a water droplet, though much smaller in size than a water droplet large enough to be visible, but having a much larger surface area to volume ratio. Yet, it would certainly fall faster than a water droplet shrunk down by evaporation to the same size as the virus particle or smaller. If corona viruses typically clumped together rather than just existing as individual, isolated viruses, that would also enhance their rate of fall when completely dry.