Share this page!

Jose-Luis Jimenez Profile picture
Twitter logo
15 Apr, 9 tweets, 4 min read
1/ Proponents of the droplet / fomite paradigm of transmission have a big problem: how to explain that transmission is x20 lower outdoors than indoors?

- V. easy to explain if #COVIDisAirborne, just huge dilution w/ outdoor air
- Impossible w/ droplets

academic.oup.com/jid/article/22…
2/ Here @CollignonPeter, who seems to be the head of infection control in Australia (ICEG) seems to invoke the "Open Air Factor", some unknown germicidal component of outdoor air.

3/ Does this save the large droplet theory?

Remember, droplets that fall within 1-2 m do so in seconds, as in this video from @WHO:

4/ Looking at some of the papers, they do see decay of microorganisms outdoors. Over AN HOUR. Not over 2 seconds.

nature.com/articles/22039…
5/ So this certainly doesn't help droplet transmission. Viruses in droplets are going to be just as infective indoors or outdoors.

The x20 reduction of transmission outdoors tells us that it is NOT the droplets that are doing the infecting.
6/ Viruses on surfaces outdoors are degraded faster just by solar UV light (and perhaps this outdoor air factor, if it is real). But surfaces transmit poorly as @CDCgov has been telling us since May 2020:

cdc.gov/coronavirus/20…
7/ So then we are only left with one explanation for x20 reduction of transmission from indoors to outdoors:

- droplets can't explain it
- surfaces transmit poorly
- airborne transmission hugely reduced outdoors by dilution

==> Airborne transmission is dominant
8/ So is there something to this "Open Air Factor"? Well, we know a lot more about atmospheric composition now than we did then.

Perhaps some short-lived radical? It can be piped indoors at 30-36 ACH, so it should have a lifetime of 2 minutes.
9/ Perhaps RO2 or HO2? Seems unlikely that those would be strongly germicidal at typical outdoor concentrations.

#AtmChem folks, any comments?

[But this is for our curiosity -- droplets are dead in the water anyway]

• • •

Missing some Tweet in this thread? You can try to force a refresh
　

Keep Current with Jose-Luis Jimenez

Jose-Luis Jimenez Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @jljcolorado

Jose-Luis Jimenez Profile picture
15 Apr
1/ DIEZ RAZONES CIENTIFICAS QUE APOYAN LA TRANSMISION AEREA DE COVID-19

Artículo revisado por pares en @TheLancet

Un honor haber colaborado en un equipo multidisciplinar liderado por @trishgreenhalgh, con @kprather88 @DFisman @zeynep @chipatucsd

thelancet.com/journals/lance…
2/ Primera: muchísimos brotes de superpropagación, q no se pueden explicar por superficies o gotas grandes ("de la OMS"), pero se explican fácilmente por transmisión por el aire

Como p. ej. el caso del coro que estudiamos nosotros (líder @ShellyMBoulder)

doi.org/10.1111/ina.12…
3/ Y recordemos que los casos de superpropagación son muy importantes para propagar la pandemia, como nos dice @nature aquí:

nature.com/articles/d4158…
Read 28 tweets
Jose-Luis Jimenez Profile picture
12 Apr
A mi esas mascarillas me parecen un peligro publico.

Luz UV hace química y puede crear tóxicos, precisamente estamos escribiendo un artículo científico sobre eso. Si lo pones en el techo de una habitación es menos importante pero si está respirando todo el aire que ha pasado...
...por uv yo desde luego no lo haría.

Y además no está cerrado entonces ese tipo de cosas nunca te aíslan completamente del aire de la habitación porque el aire se mueve de forma caótica
Y si la persona está infectada, el virus parece que se expande por la habitación sin control?

O sea que sería un chisme totalmente egoísta?
Read 4 tweets
Jose-Luis Jimenez Profile picture
12 Apr
1/ Presento en el 2o Congreso COVID de España a las 19 h, empezando en 5 minutos.

Inscribirse es gratis, y se puede hacer aqui:

2congresocovid.es
2/ Si quieren ver mis diapositivas (incluyendo muchas mas de las que me da tiempo a ensenar hoy) pueden ir a:

Bit.ly/COVID-aerosols2
3/ Para cosas practicas de como protejernos, no me da tiempo en esta ponencia, pero tiene 65 paginas de preguntas frecuentes contestadas por cientificos punteros aqui:

tinyurl.com/preguntas-espa…
Read 11 tweets
Jose-Luis Jimenez Profile picture
10 Apr
Dr. Conly (@WHO IPC Chair): "COVID is situational airborne"

Thomas Kuhn in “Structure of Scientific Revolutions” uky.edu/~eushe2/Pajare…

"Scientists faced w/ failing theory “devise numerous articulations & ad hoc modifications of their theory to eliminate any apparent conflict”
Last summer's "magical droplets" have not mutated into "situational airborne transmission"

Yes, it is transmitted in situations involving people re-breathing a lot of the same air indoors.

Not in situations outdoors o w/ good ventilation etc. when not re-breathing the same air.

So I guess "situational" is one way to put it...
Read 5 tweets
Jose-Luis Jimenez Profile picture
10 Apr
1/ La principal forma de transmisión del coronavirus es por aire

- T: ¿Qué significa que el virus está en el aire?

- JLJ: No es una definición fantasmagórica, no significa que el virus va a viajar kilómetros...

telam.com.ar/notas/202104/5…
2/ ... y va a venir a infectar; significa que de las personas infectadas sale como un humo invisible que puede contener el virus con capacidad de infectar; ese humo son los aerosoles respiratorios, son partículas muy pequeñas, invisibles, que se quedan flotando en el aire."
3/ "¿Cuándo respiras muchos aerosoles de otro?. En 2 situaciones: cuando estás muy cerca, sobre todo sin mascarilla/barbijo, o cuando compartes el aire en una habitación cerrada, pq el espacio cerrado atrapa el aire q esa persona está exhalando. Son 2 situaciones muy frecuentes"
Read 23 tweets
Jose-Luis Jimenez Profile picture
9 Apr
1/ On Twitter Sociology, Part 2

I've used Twitter extensively only during the pandemic. Most interactions are useful, including open discussions w/ other scientists & professionals, and lots of Q&A with the public.
2/ Then there are the trolls and perhaps bots. More common in Spain's twitter than in other spaces (not sure why).

I hesitated at first, but now when it is clear that they are not listening but just trying to stir idle discussion, I just block them.
3/ I don't block ppl (general public or especially scientists) that disagree with me, but that do so thoughtfully and respectfully. In fact I've learned the most from that kind of ppl.

We scientists know that ppl disagreeing with you is normal, and that's often how we learn.
Read 10 tweets

Did Thread Reader help you today?

Support us! We are indie developers!

This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!

Follow Us on Twitter!

Like this author's thread?

Get emails when @jljcolorado has new unrolls!

Check out other threads from @jljcolorado!

Read all threads by @jljcolorado