Prof. Jose-Luis Jimenez Profile picture
Sep 29, 2020 5 tweets 2 min read Read on X
1/ What does "aerosol" or "airborne" transmission suggest to people?

I am impressed by the accuracy of the responses. Indeed the **most important implication is that transmission occurs in shared room air**, and protecting against that.
2/ Transmission in close proximity is ALSO dominated by aerosols (sciencedirect.com/science/articl…).

But since social distance and masks work well for that, the practical implications of accepting aerosol transmission are much smaller for that.

And indeed many fewer ppl think of that
3/ Trans. beyond shared room ("long range") possible, but much less likely.

Won't be clear till there is low prevalence.

E.g. long range trans. for smallpox could only be proven for an outbreak in complete absence of community transmission: academic.oup.com/aje/article-ab…
4/ Transmission outdoors is possible but FAR less likely than indoors. Overwhelming majority of superspreading is indoors

Trans. can happen outdoors, but very unlikely except for close conversation without masks (there are some documented cases of transmission this way)
5/ Of course many responses to this poll were from people who follow my colleagues & I, and have learned about aerosol transmission through the discussions and materials we provide

But this demonstrates that if we provide accurate info, it can be accurately understood.

• • •

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

Keep Current with Prof. Jose-Luis Jimenez

Prof. 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

Apr 18
1/ @WHO has published a report on updated terminology for disease transmission

I've seen some debate about it. My take:

- Terminology itself is ok. Big progress
- But no recommendations of how to protect!

Report:

Press release: who.int/publications/m…
who.int/news/item/18-0…
2/ The report was likely the result of intense pressure on @WHO during the pandemic:

- They denied that #COVIDIsAirborne on March 2020
- They finally accepted it 2 years later

nature.com/articles/d4158…
@WHO 3/ To their credit, @WHO did invite some of their critics to be part of the committee.

What was the terminology before. In medical circles:

- droplet transmission: if it happened in close proximity, or if particles were > 5 microns

- airborne transmission: if it happened far
Read 34 tweets
Mar 28
1/ New paper in @ScienceMagazine: "Mandating Indoor Air Quality for Public Buildings"

Explaining current status of indoor air quality standards (in short: bad or non-existent), the huge health benefits that would arise from them & proposing a path forward
science.org/doi/10.1126/sc…
Image
2/ "People living in urban & industrialized societies, which are expanding globally, spend more than 90% of time indoors, breathing indoor air (IA)."

"Most countries do NOT have legislated indoor air quality (IAQ) performance standards for public spaces"

science.org/doi/10.1126/sc…
3/ "Few building codes address operation, maintenance, and retrofitting, and most do NOT focus on airborne disease transmission."

"We propose that Indoor Air Quality (IAQ) standards be mandatory for public spaces"

science.org/doi/10.1126/sc…
Read 14 tweets
Oct 4, 2023
1/ Checking the ventilation by measuring CO2 as I travel to the #AAAR2023 conference

@RideRTD bus to Denver airport. Bus route had started 3 min before I got in, already 1500 ppm

Typical of these @RideRTD buses, poor ventilation Image
2/ Not getting any better as time passes in the @rideRTD bus to the airport...

7% of the air is being re-breathed, it has already been in someone else lungs when each of us breathe it. Image
@RideRTD 3/ Given the often poor-to-mediocre ventilation in US transportation systems, I wear N95 masks (not KN95, less good)

In this case @3M VFlex, which I tested at 99.99% filtration for myself

It also stays sealed when I talk, doesn't distort my speech (& add to my Spanish accent) Image
Read 14 tweets
Oct 2, 2023
1/ Video de mi presentación sobre "Transmisión de enfermedades por el aire: cómo funciona, por qué se malentendió, y cómo reducirla"

como parte de la presentación del libro de ventilación de @aireamos

2/ Las diapositivas se pueden bajar de este enlace.

(Son de una charla más larga así que tienen más detalles, pero están todas las de la presentación de @Aireamos)

drive.google.com/file/d/1Bs0RRG…
@aireamos 3/ Miguel Ángel Campano @MA_Campano y @Aireamos han sido los motores del libro de ventilación:

Read 4 tweets
Sep 1, 2023
1/ Measuring CO2 indoors in a 10 day trip from US to Europe & back

Bus @RideRTD to Denver airport, poorly ventilated as usual.

We have not left town yet! In previous trips it kept increasing, we'll see this time. Image
2/ For background on what CO2 indoors indicates and more details, see

TLDR:
- We exhale 40000 ppm CO2
- Outdoors: 420
- Each 400 extra ppm indoors = 1% extra rebreathed air
- CO2 makes us dumber, indicator of virus & pollutants. Does not capture filteringdocs.google.com/document/d/e/2…
3/ Or by reducing recirculation. Some recirculation is ok if well-filtered, saves energy.

Energy-recovery ventilators allow ventilating well with limited energy use.

Read 18 tweets
Aug 17, 2023
1/ Webinar from @PsrColorado on mixing hydrogen (H2) with fossil (aka "natural") gas

- NOT a good idea
- Subsidized by Inflation Reduction Act in US

- Creates problems, but less at the point of combustion, more elsewhere Image
2/ "Brown hydrogen" is made from coal

HUGE CO2 emissions, unacceptable Image
3/ "Gray hydrogen" is made from fossil ("natural") gas

- Leaks of NG (methane) lead to warming
- Making H2 from NG generates CO2, more warming

BAD idea Image
Read 20 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

Don't want to be a Premium member but still want to support us?

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

Donate via Paypal

Or Donate anonymously using crypto!

Ethereum

0xfe58350B80634f60Fa6Dc149a72b4DFbc17D341E copy

Bitcoin

3ATGMxNzCUFzxpMCHL5sWSt4DVtS8UqXpi copy

Thank you for your support!

Follow Us!

:(