Discover and read the best of Twitter Threads about #Ventilation

Most recents (24)

1/ Public Health @cityofhamilton, to stamp this out fast, you should issue an order requiring off-site air-gapped isolation/quarantine accommodation for those with an active infection.…
2/ Off-site air-gapped isolation can take the form of individual trailers, or a newer hotel that has been tested for dwelling unit compartmentalization.
3/ We know from decades of building science that there is significant unintentional air transfer between suites, especially in older buildings.
Read 7 tweets
❗️@WHO updates on main mode of SARS-CoV-2 🦠 transmission❗️

2021.04.30 Q&A ⤵️ ‘How does #COVID19 spread between people?’

I cannot overstate how seismic this paradigm shift is, and should be, in guiding a revised Risk Assessment & Controls framework.… Image
The virus 🦠 SARS-CoV-2 can spread from an infected person’s mouth or nose in small liquid particles when they cough, sneeze, speak 🗣, sing 🎤, or breathe🧘🏻‍♀️.

[why mask needs to cover👃& 👄]

These particles range from larger respiratory droplets 💧 to smaller #aerosols 💦. Image
The SARS-CoV-2 virus 🦠 spreads *mainly* between people in close (short-range) contact, typically within 1 meter (3 feet) of each other.

When #aerosols or droplets containing the virus 🦠 are INHALED or come into DIRECT CONTACT with the [mucous membranes of] 👀,👃, or 👄. Image
Read 6 tweets
U of T is making all classrooms achieve 6 ACH with #ventilation and #filtration, the same as for health care patient exam rooms. They measured air flow.
THIS should be the target for all Ontario daycare, elementary, and secondary schools too.…
Children will be the last to be vaccinated. Schools & daycares will benefit immensely from reduced cold, flu, seasonal allergies by upgrading to 6 ACH. The time to start was a year ago. The next best time is tomorrow.
Big shout out to @ShellyMBoulder and the UC Boulder team that led the way on this last summer.
Read 4 tweets
ICYMI: Resource page on COVID transmission & prevention (focus on airborne aerosol spread) is up to:
☑️580+ media articles
☑️285+ science articles
☑️tons of videos; infographics; webinars; tweet threads; reports & tools
☑️scientists to follow
☑️more (1/x)
(2/) If you are looking to learn about #COVID transmission & prevention, this curated page is a long & growing set of educ. resources, w/ focus on inhalable #aerosol, #airborne spread.

Lots on aerosol basics, new science, #masks, #ventilation, #COVIDCO2+…
(3/) The COVID page is not meant to be 100% comprehensive (one-person effort; be gracious), but a broad & freely available source for practical & important info.

As always - feel free to send any important articles I've omitted or other suggestions. 🙏…
Read 3 tweets
Naaah, the massive gym outbreak couldn't possibly be lack of #ventilation. That rooftop unit is in excellent condition. 😬😬😬
I don't even know what I'm seeing. Is that charred polyisocyanurate spray insulation?
To be fair it's only one of six units, the others appear to be better.
Read 5 tweets
So today I was lucky enough to get a vaccine.

Now I am eagerly waiting for day 4 to pass uneventfully.

Also wore my lucky shirt for the win.

Before going for my AZ vac I wondered about consent when the choice is either (a) consent to the AZ vac or (b) do not consent to the AZ vac. I thought about VIPIT and my discussion with a med friend about how many people that might be.
Him: if we vax say 10m with AZ and expected rate of VIPIT is 1:500000 (Buttery) then expect 20 cases and 6 deaths (assuming mortality of 30%).

I reflected that it was a risk number I was being asked to consent to, a risk of being one of the 6 in 10m c/f no severe covid/death
Read 13 tweets
1/ Helpful clarification by #CDC w/ important practical implications to avoid wasting energy & money on excessive surface cleaning:
"each contact with a contaminated surface has less than a 1 in 10,000 chance of causing an infection"

HT @JudahWorldChamp…
2/ Important to note that COVID can potentially spread in individual cases via direct/surface contact, via cannonball-like droplets, or inhalation of aerosols.

The brief clarifies that surfaces are statistically very unlikely to cause many infections; so focus most on the air.
3/ From CDC brief today:
"However, based on available epidemiological data and studies of environmental transmission factors, surface transmission is not the main route by which SARS-CoV-2 spreads, and the risk is considered to be low."
Read 5 tweets
Partial good news out of @CDCgov today.…
Recognition that fomites are a minor route, and stop the #hygienetheatre . Also good, and pathbreaking that they cite #QMRA studies in support. 1/N
Interesting that they use a 1/10,000 from a surface contact as being indicative of low risk from fomites (many of us have seen that number before). But, still some problems in this updated science brief. 2/N
Opening sentence: "The principal mode by which people are infected with SARS-CoV-2 (the virus that causes COVID-19) is through exposure to respiratory droplets carrying infectious virus." While they don't use the word #aerosol in the body 3/N
Read 5 tweets
(1/8) Time for engineering solutions.
Can we reopen #hotels #restaurants #bars on 1 May 2021 (or even before)? Taking into account measures below, answer is YES. Based on peer-reviewed published research & solid arguments. Scientific evidence & arguments below.
(2/8) We did STRESS-TEST: worst-case scenario in #aerosol production: full #gym with all persons exercising vigorously. We tested combination #ventilation & #aircleaning: cost- & energy-efficient solution to reduce aerosol particle concentrations. See:…
(3/8) Movie of this experiment: 35 test persons exercising; different settings #ventilation & #aircleaning:
Work by @TUeindhoven @plasmamade supported by @Sportinnovator & @gem_Eindhoven Ongoing #CFD simulations supported by @Microsoft @ANSYS
Read 8 tweets
What do we mean by #UseAirbornePrecautions? There are clear guidelines in health care settings, but what do we mean by it for the public? A 🧵 of 🧵(met-thread) on this. Strap in, this will be long 1/
2) First, this is not the first #airborne problem we have faced, and it won't be the last. And not all of them are exotic pathogens. Some could be as mundane as dust, smoke, pollens, volatile/semi-volatile organic compounds. They are all around our living space
3) Not all #airborne troubles are created equal. For example, I am a lot more allergic to cigarette smoke than incense. This varies from person to person and trouble to trouble. Some do not have any smell and can still be a "headache".
Read 41 tweets
1) Morning @GavinWilliamson, just reading the update from @PHE_uk @GOVUK below ⬇️.…
2) Wondering how this particular bit of advice ⬇️ will play out in schools & early years settings after #Easter?

Crowded poorly ventilated classrooms w/ up to 30 kids from different households are the very essence of HIGH RISK spaces. Dining rooms/PE halls could even be worse!
3) If I’ve understood it correctly anywhere in the RED AREAS needs extra attention?

Read 13 tweets
New pre-print: “Respiratory aerosols and droplets in the transmission of infectious diseases”

Happy to contribute to this deeply detailed review paper by Mira Pöhlker et al. & colleagues at the Max Planck Institute for Chemistry.


A 🧵summary (1/x)
2/ Preprint review is very detailed: 50 pgs, 20 figures, 7 tables, >360 references.

☑️Reviews literature:
- Respiratory particle size distributions (rPSDs)
- Physical properties
- Emission & shrinkage mechanisms
☑️New multimodal parameterization of rPSDs
☑️Practical perspective
3/ The review ends by showing a parameterized size distribution of respiratory particles & the risks in different parts of a room using #masks, #ventilation, and #filtration. Broad application to SARS-CoV-2 other respiratory viruses.

Read 16 tweets
Daily Bookmarks to GAVNet 03/30/2021…
Complex Systems: Volume 30, Number 1 (2021)

#complexity #journal #CurrentIssue
The Law of Regression to the Tail: How to Survive COVID-19, the Climate Crisis, and Other Disasters…

#RegressionToTheTail #risk #FatTailedRisk #COVID19 #pandemics #ClimateCrisis #RiskMitigation
Read 8 tweets
1/ Airborne transmission, and the 3 feet vs. 6 feet question: A 🧵 with links for policy advocates trying to sort through the science...

WARNING: Nuance Ahead
2/ COVID-19 is mainly spread by inhaling small particles.

Timeline with illustrations, articles, studies:
#COVIDisAirborne #masks4All #bewareOfSharedAir #ventilation. See:… via @AerosolizedC19

Airborne Transmission FAQ by experts:
3/ In addition, here's Dr. @linseymarr and Dr. @jljcolorado's bibliography regarding "Transmission of COVID-19." They're top experts.

"What We Know" 2021 summary: Respiratory plumes/short-range "close" exposure are <1.5 m (4.92 ft)
Read 27 tweets
[Thread] Chicago didn’t have a second wave of Spanish Flu.. so what did they do, & how did the city re-open when there was no vaccine? #Ventilation #COVID19 1/ are the public health measures that Chicago took on the autumn of 2018
‘open window ventilation in all school rooms.. pupils warmly dressed.. daily check on pupils & absentees in schools.. use of masks.. landlords required to heat homes.. ’ 2/
..’isolation & quarantine.. home nursing provided (see my thread on home nursing).. churches required to improve ventilation.. 150 city health officers on full time service’ 3/
Read 17 tweets
💈One Year On. Our scrapbook.

Kids do get #COVID19
Kids can be #Asymptomatic or #Atypical.
Kids can have a mild infection, or get #PIMS
Kids can get #LongCovid

2000 kids NOT yet better.
Families disbelieved.

⚠️Contains graphic images. #MothersDay
The numbers of children with #LongCovid are rising with every #COVID19 infection.

⚠️1 in 8 primary age children will get Long Covid
⚠️1 in 7 secondary age children will get Long Covid.

It appears to makes no difference if a child has a pre-existing condition or not.
Tragically children can die.

Thankfully the numbers are low compared with adults.

Every family that has lost a child will be devastated, the fact the numbers are low will have no bearing on their grief.

#LongCovidKids #MakeSchoolsSafe
Read 6 tweets
🧵1/ The #CDC update today (2/26) on "Ventilation in Schools and Child Care Programs" looks like good progress.

Details on #ventilation, #filtration, #bettermasks, w/ helpful links. Seems they're listening to @kprather88 @j_g_allen @CorsIAQ and others?…
2/ The relatively short #CDC page seems to have more succinct, yet clear #K12 guidance & connection to other pages of support.

Though I admit, I haven't digested yet fully. What are your takes? (also e.g. @jljcolorado @linseymarr @ProfCharlesHaas @Don_Milton @ShellyMBoulder)
3/ I was pleased to see early mention that "Wearing a well-fitting, multi-layer mask helps prevent virus particles from entering the air or being breathed in by the person wearing the mask."

(BTW, need for good fit implies aerosols)

Links (twice) here:…
Read 17 tweets
#SARSCOV2 & #VariantsOfConcern
#B117 #B1351 #P1
SARS-CoV-2▪︎Genetically related to 2003 SARS virus▪︎Named Feb 11 2020 #COVID19▪︎Feb 24 2021 Global Cases 112,409,584, Deaths 2,492,420▪︎Feb 24 2021 US Cases 28,313,003, Deaths 504,295

#UKvariant #B117▪︎Discovered Sept 2020▪︎80+Countries▪︎1st US Dec 2020▪︎Feb 24 2021 US Cases 1,881 across 45 States▪︎Estimated 30-50% more transmissible (spreads easier&faster)▪︎UK suggests the strain may cause more severe cases & 30% increased risk of death. /2
#SouthAfricanVariant #B1351▪︎Appx same time as #B117▪︎Feb 24 2021 US Cases 46 across 14 States▪︎Dominant strain in Zambia Dec2020▪︎Estimated 50% more transmissible▪︎No evidence yet of increased severity▪︎Mutated Spike Protein allowing latch to human cells easier/3
Read 9 tweets
Hey Tucker Carlson: #BillGates called, he has #proof for your #crossfit gym owner.
HINT: #ItsScience
@CDCMMWR #COVID19 cases among attendees of indoor high-intensity classes at a gym where many attendees did not wear masks consistently during exercise /1
Increased respiratory exertion facilitates #SARSCoV2 transmission; outbreaks linked to indoor activities have been reported. /2
Aug 2020, 55 #COVID19 cases were identified among 81 attendees of indoor high-intensity classes at exercise facility. 22 (40%) persons w/COVID-19 attended on or/after the day symptoms began. Most (76%) wore masks infrequently, including persons w/(84%) & w/o COVID-19 (60%). /3
Read 5 tweets
One of the most bizarre & troubling bits of the #ReopeningSchools saga is that @educationgovuk & @BorisJohnson have ignored every single plea from teachers, early years staff, pupils & their families to #MakeSchoolsSafe & wasted all the months they have had to do so. 1/14 🧵
2)They’ve turned their backs on plentiful advice from #SAGE, @IndependentSage & @NEU.
Even @CMO_England has made his reservations as clear as he can from a rather difficult position.
But they’ve put their collective fingers in their ears & metaphorically said “La La La La”!
3) @GavinWilliamson & @halfon4harlowMP CLAIM the motivation for a speedy full opening of all school & early years facilities is the WELFARE OF CHILDREN!
They repeatedly cite educational, emotional, social & psychological needs.
Read 14 tweets
1/ Here's a quick bite (< 2.5 minutes) of overview on infectious respiratory aerosol emissions, #ventilation, and using #CO2 monitors as a tool in the fight against COVID & for healthy indoor air.

Thx to @KateM_NYC @YahooNews for the interview. #COVIDCO2…
2/ I recently gathered several interesting stories from recent CO2 measurements as well as a simple example of how I had fun measuring the ventilation rate in my house.

Peruse #COVIDCO2 for many more examples.
3/ Measuring #CO2 to estimate ventilation rate is a quick way of approximating the amount of "rebreathed air" (the portion of air you breath that has already been in someone else's lungs).

See thread by @CorsIAQ for good details here.
Read 6 tweets
1/14 Morning @SophyRidgeSky, just watched the interviews w/ @DominicRaab @annelongfield @timspector & @bphillipsonMP re #schoolsreopening fully on 8th Mar.

Discussions focused on dates, primary vs secondary, catch up plans, mental health concerns, vulnerable children....

Has the MSM been banned from mentioning mitigation measures?
Are British children/teaching staff different to those across the world?
3/NO FIGURES on how many children get #COVID19?
NO MENTION of how many become seriously ill, are hospitalised or die?
Absolutely NO WORD about the 1 in 7 or 8 children who get #LongCovid!
NO ADVICE for parents of children w/ diseases like Diabetes, severe Asthma etc.
Read 14 tweets
@dgurdasani1, you are a legend 👏!

PLEASE please listen to this from 07.20-40.30.
You will not regret it.

It clearly demonstrates the dangers of those without any CLINICAL knowledge & expertise being able to make crucial decisions that effect so many lives.
1/15 a thread.
Questions for the MODELLERS & MPs...

Have you actually seen a child poorly w/ #COVID19? It can be extremely frightening for both child & parents.

Have you seen/spoken to the parents of any children suffering w/ #LongCovid?
Why not listen to what parents & Drs are saying? 2/
#COVID19 is a multi-system disease with w/ many negative outcomes other than hospitalisation or death.



#LongCovid in both adults & children can be v debilitating & there’s currently v little knowledge about the long term prognosis. 3/.
Read 15 tweets
1. @JoeNBC @morningmika @Morning_Joe Former teacher here: Once again everyone wants to put in their 2 cents w/o input from those who have to deal w/implementing the policies. You, the politicians, the parents, the scientists, the doctors et al want #AmericanSchools to #Reopen!
2. You need to consider that most school bldgs are more than 50 yrs old. A local HS built circa 1970 has narrow slit like windows that don't open. So much for #Ventilation! #Classrooms are small & don't allow for social distancing. This is further complicated by having....
3. 20-25 #Students per class. Several yrs ago a friend had 32 students in her K-class due to budget cuts! I don't know the number in her class now but I doubt there's been a great change in the number. The kids who take buses to school are on top of each other all the time.
Read 7 tweets

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