Share this page!

Enter URL or ID to Unroll

You can paste full URL like: https://x.com/threadreaderapp/status/1644127596119195649
or just the ID like: 1644127596119195649

How to get URL link on X (Twitter) App

  1. On the Twitter thread, click on or icon on the bottom
  2. Click again on or Share Via icon
  3. Click on Copy Link to Tweet
  4. Paste it above and click "Unroll Thread"!
  5. More info at Twitter Help
Al Haddrell Profile picture
@ukhadds
Jun 22, 2023 • 3 tweets • 1 min read • Read on X
I’m proud to have our latest research published on how long #SARSCoV2 remains infectious while airborne! We studied the fundamental processes that drive the loss of viral infectivity in the aerosol phase. #COVIDisAirborne

Here’s a thread going over some of the findings. Image
@ParentMishmash Interesting question btw. Actually, all of your questions have been. Thanks!
@J__Doh Here are the specific values. So, about 10 to 20 times faster decay in sunlight (depending on the season). Image

• • •

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

Keep Current with Al Haddrell

Al Haddrell 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 @ukhadds

Al Haddrell Profile picture
Nov 1
A study came out last month looking at how long influenza remains viable in the air.

In the article, it highlights some of my larger concerns in what is happening in the field of airborne viral decay.

First off, here’s the article:

frontiersin.org/journals/micro…
Out of the gate, the article is fine.

My largest critique is the assertion that 99% decay means something. Why 99%? Why not 98%? Or 97… or 92… 87%? 83.5%?
While it sounds like I’m being coy, I’m not. 99% is an arbitrary number. That’s okay, but don’t act like it’s an agreed upon value. It isn’t.

Anyway, this is a minor issue (of someone in the field). The general trends presented by the authors is supported by their work. Image
Read 16 tweets
Al Haddrell Profile picture
Oct 5
How does humidity affect the transmission of SARS-CoV-2?

There's a lot of confusion around this question. Is dry air or wet air better? Somewhere in between? In this explainer video I dive into this and go into what we know, and what we don't.
This is the first part of a (what I expect to be) a two part series. In this video I discuss how humdity affects transmission. In the followup I will dive into why humdity does, or does not, have an effect.
This is the second video on my channel (like and subscribe!).

If you found this one interesting, you may also find my other one interesting as well.
Read 4 tweets
Al Haddrell Profile picture
Sep 16
Are respiratory aerosol liquid, solid, neither or both? What about the virus, where does it go? Let's get into this.
We published some work on this previously where we studied how respiratory aerosol changes once it is exhaled.

tandfonline.com/doi/full/10.10…
Once exhaled, the aerosol will begin to lose water. The rate in which the aerosol loses water will depend on the humidity (loses size faster in dry air). The humidity will also determine both the final size and particle structure. Image
Read 6 tweets
Al Haddrell Profile picture
Sep 15
There's been a lot of discussion about the size of exhaled aerosol that contains the most virus. For the most part, it's thought to be in the ~1 to ~5 micron range. There's a little bit of variation between studies, but that's roughly the size of concern (“Viral”).
Image
If you are curious, this is due to a combination of the size distribution of exhaled aerosol and maximum conc that the virus can grow in the respiratory fluid. Here we looked at aerosol size, others have looked into the viral load as a function of size.tandfonline.com/doi/full/10.10…
So, N95 masks work well in filtering out the aerosol size region that is most associated with airborne viral transmission. The key really does come down to fit.

hse.gov.uk/respiratory-pr…
Read 6 tweets
Al Haddrell Profile picture
Aug 14
Huge paper exploring the relationship between exhalation aerosol counts and CO2 has just been published.

Take home message: CO2 and aerosol strongly correlate in silence. Vocalisation causes this relationship to breakdown (way more aerosol than CO2).
pubs.acs.org/doi/10.1021/ac…
This has huge implications on how CO2 can be used to estimate the aerosol counts in a room. Noise matters!!

I've mentioned this work previously, it's great to see it finally published so everyone can have a good look. Image
I mentioned this work in a previous thread where I discussed the many ways in which CO2 is associated with Covid transmission.

Read 8 tweets
Al Haddrell Profile picture
Aug 5
"How does humidity affect SARS-CoV-2 transmission?"

Whenever this question comes up, the answer I give is along the lines of “it’s complicated”.

So, what exactly do I mean (a 🧵)?

Context: When considering airborne transmission of a respiratory virus, numerous factors are involved.

They ALL matter.

Moreover, they are all independent. Meaning, a certain parameter may affect each factor differently. Image
Since the dawn of the field (1950s/60s), the airborne survival of viruses has been measured as a function of relative humidity (RH) and temperature. There are numerous reasons for this, such as to understand viral transmission and to inform about why the virus decays. Image
Read 15 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!

Send Email!

:(