Prof. Jose-Luis Jimenez Profile picture
Apr 7, 2022 31 tweets 18 min read Read on X
1/ CO2 during international airplane travel

Will tweet the levels in different parts of the trip from the US to Spain with @lufthansa

Not great in the check-in area. Lots of mediocre masks (poorly fitting surgical or cloth), also some N95s

#covidCO2 Image
2/ Waiting at the security line @DENAirport

Ok, not bad given the number of people Image
3/ Departure Gate at @DENAirport. Not bad, despite lots of people.

#covidCO2 Image
4/ Still waiting to board. Impressed with @DENAirport terminal ventilation, despite crowding Image
5/ Settled at our seats, we were able to board early.

Improperly masked @lufthansa flight attendants asked us to remove our elastomeric N95 masks and put surgical masks instead (!!). We refused and were able to convince them that these are real N95.

#covidCO2 Image
6/ Boarding is progressing, and CO2 is rapidly climbing. Poor ventilation, does not seem to be at full speed.

Not impressed with @lufthansa so far.

#covidCO2 Image
7/ CO2 during the flight hovered around 1200-1600 ppm. Not as bad as what others have repo on other airlines, and with the filters the risk is lower than it would appear w/ CO2 alone. ImageImageImage
8/ Munich airport @MUC_Airport. CO2 ok, although we are in an area with very few people.

We'll see as we go to more crowded areas.

#CovidCO2 Image
9/ Another part of @MUC_Airport by our departure gate. Not bad.

#covidCO2 Image
10/ Boarding our last @lufthansa flight at @MUC_Airport to Spain.

Going up, we'll see how high it gets.

#covidCO2 Image
11/ Finished boarding, pretty high. Image
12/ Getting pretty bad as we taxi towards takeoff

#covidCO2 Image
13/ the terminal at @Aeropuerto_BCN is ok as well. Image
14/ I'll continue to document indoor CO2 in this thread as we travel around Spain.

At the @CosmoCaixa museum of science in #Barcelona:

Lots of people, but good ventilation

#CovidCO2 Image
15/ Planetarium at @CosmoCaixa, at the end. Half full, good ventilation Image
16/ Checking that the CO2 mitor is well calibrated with the outdoor concentration. Makes sense since today is pretty windy in Barcelona. Image
17/ Starting a 2 hrs train trip on the Spanish high speed train (AVE @AVEMadBcn) from @Renfe. 70% occupancy.

Increasing, we'll see how high it gets Image
18/ I try to eat at a different time than others, ideally before. I have a water bottle with a straw type connection (pic) that I can slip under the mask.

But you have to accept some risk while traveling (or not eat and drink, that'd be too much for me)
Image
19/ Later into the train trip on @Renfe @AVEMadBcn. CO2 has increased, but less bad than what I have seen others post in other trains.

Presumably there is filtered recirculating air, so overall the risk is not too high. Image
20/ @elcorteingles departament store in #Zaragoza (Independencia).

Quite a few people, but very good ventilation. Image
21/ @Movistar mobile phone shop in Zaragoza. 12 people in a large shop. Not great given few ppl, but not too bad. Image
22/ From the same @Movistar phone shop. Ventilation wasn't great, but they had signs on the phone displays that you should not touch the phones before someone disinfects them for you...

Stuck in 2020, despite ZERO demonstrated cases of surface transmission & DOMINANT airborne... Image
23/ Checking the comparison with a similar meter, which is an easy way to check that the measurement is likely correct.

Normally within 30-50 ppm would be good, these 2 being so close is great but better than typical.

#covidCO2 Image
24/ En @CosmoCaixa en #Zaragoza en una actividad para niños. Ni bien ni mal. Image
25/ Climbing Gym @bulderland in #Zaragoza, Spain.

Definitely too high for a gym.

Also signs saying that it is ok to remove the mask when climbing, when that's the most important time to wear it! Higher aerosol emissions and inhalation when exercising... Image
26/ Same gym, completely outdated protocols, with high emphasis on disinfection. Despite ZERO proven cases of surface transmission.

Nothing about airborne transmission, other than masks. No specification of type. Many mediocre masks.

Just an example, same almost everywhere... Image
27/ Restaurant El Lienzo in Ávila, Spain. Eating outdoors w/ family. Indoor well ventilated 625 ppm.

But bathroom doesn't have ventilation, seems to be a problem in many places. Image
28/ @aeropuertoMAD, good ventilation as in other airports.

But the still emphasis in useless disinfection measures Image
29/ In the tramway in Zaragoza @tranviadezgz

Not rush hour, but quite a few people. Some small windows are open. I think there is some filtration, so Ok but not great.

Everyone masked, although many poorly fitting surgical or KN95 (nose esp.). Few ppl talking. Overall low risk Image
30/ At the Zaragoza @zaragoza_es train station. Huge building, good ventilation due to openings for trains to go in and out (plus other systems). Same levels as outside, very safe. Image
31/ Just jumped into the train @Renfe @AVEMadBcn. Completely full, plenty of mediocre masks such as surgical band even cloth. Some masks below the nose.

And horrible ventilation... Image

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More from @jljcolorado

May 26
1/ Survey of CO2 indoors during trip

CO2 (above ~400 ppm outdoors) indicates the amount of exhaled air (& virus) trapped in a space

Also per recent scientific results by @ukhadds, CO2 helps SARS-CoV stay infectious in air much longer

@united flight boarding, pretty terrible! Image
2/ This is the trip so far:

-Low outdoors
-Pretty high ~2000 in @RideRTD bus to airport
- ok ~800 at @DENAirport, except restroom ~1500. Not sure why restrooms at this airport are so often poorly ventilated
- Then boarding on @united, ventilation OFF, so huge increase till ON Image
3/ For details of the recent results on how and why CO2 makes SARS-CoV-2 stay infectious much longer in the air, see this recent thread by @ukhadds

Read 9 tweets
May 8
1/ "After four years of fighting about it, @WHO has finally proclaimed that viruses, including the SARS-CoV-2 virus that causes COVID, can be spread through the air"



By @maggiemfoxscientificamerican.com/article/a-figh…
2/ "It took four years to get here because some leaders in public health, medicine and science clung too tightly to precision and semantics"

"One particular moment of shame came on March 28, 2020, when WHO tweeted: “FACT: #COVID19 is NOT airborne.”

3/ "Words matter. When people heard that COVID might spread on surfaces, they wasted time wiping down groceries. People who misunderstood airborne spread needlessly wore masks on outdoor walks and veered off sidewalks to avoid their neighbors."
Read 7 tweets
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

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