While the subway in Vienna generally has rather low CO2-values (just 1% of the measured journeys are above 1400ppm so far and 70% below 800ppm), there has been a outlier today above 2000ppm and even 2800ppm in it's peak. There are currently construction works going on at the main line
October 27, 2026 at 9:34 PM
While the subway in Vienna generally has rather low CO2-values (just 1% of the measured journeys are above 1400ppm so far and 70% below 800ppm), there has been a outlier today above 2000ppm and even 2800ppm in it's peak. There are currently construction works going on at the main line
It’s an illness, I think. A kind of psychopathy. Very sad for our biosphere & must end sooner rather than later, before the oceans, which are already hypoxic in places, become anoxic. If that happens then all air breathers die. As happened 220 million years ago (CO2 was 800ppm; we’re over half way)
October 20, 2026 at 5:47 PM
It’s an illness, I think. A kind of psychopathy. Very sad for our biosphere & must end sooner rather than later, before the oceans, which are already hypoxic in places, become anoxic. If that happens then all air breathers die. As happened 220 million years ago (CO2 was 800ppm; we’re over half way)
The point being that when atmospheric PPM reaches 800ppm, the oceans turn anoxic, meaning instead of producing oxygen (through algae blooms etc) they produce sulphur. I don’t care how rich you are, you cannot breathe sulphur & we’re already over half way there (430ppm), so JUST THINK a bit.
October 20, 2026 at 7:43 PM
The point being that when atmospheric PPM reaches 800ppm, the oceans turn anoxic, meaning instead of producing oxygen (through algae blooms etc) they produce sulphur. I don’t care how rich you are, you cannot breathe sulphur & we’re already over half way there (430ppm), so JUST THINK a bit.
Le Haut conseil de la santé publique recommande de ne pas dépasser #800ppm afin de se protéger contre la #Covid et contre les épidémies d’infections hivernales. Les 1000 à 1500 ppm de @anses-fr.bsky.social sont beaucoup trop élevés sauf pour des courts moments (10 mns max) !
#AutodefenseSanitaire
#AutodefenseSanitaire
October 18, 2026 at 1:43 PM
Le Haut conseil de la santé publique recommande de ne pas dépasser #800ppm afin de se protéger contre la #Covid et contre les épidémies d’infections hivernales. Les 1000 à 1500 ppm de @anses-fr.bsky.social sont beaucoup trop élevés sauf pour des courts moments (10 mns max) !
#AutodefenseSanitaire
#AutodefenseSanitaire
The health standards for indoor air quality is 600ppm. The CDC set the max at 800ppm. Over 2000ppm means the CO² levels are dangerously high and can cause brain damage.
October 12, 2026 at 12:58 AM
The health standards for indoor air quality is 600ppm. The CDC set the max at 800ppm. Over 2000ppm means the CO² levels are dangerously high and can cause brain damage.
Hampshire children are testing positive for COVID-19
SARS-CoV-2 spreads primarily through respiratory particles in air
✅ Keep unwell children away from school
✅ Ventilate. Monitor CO₂ to know ventilation is good. Below 800ppm is good
✅ Use HEPA filtration where needed
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SARS-CoV-2 spreads primarily through respiratory particles in air
✅ Keep unwell children away from school
✅ Ventilate. Monitor CO₂ to know ventilation is good. Below 800ppm is good
✅ Use HEPA filtration where needed
1/3
October 7, 2026 at 9:10 PM
Hampshire children are testing positive for COVID-19
SARS-CoV-2 spreads primarily through respiratory particles in air
✅ Keep unwell children away from school
✅ Ventilate. Monitor CO₂ to know ventilation is good. Below 800ppm is good
✅ Use HEPA filtration where needed
1/3
SARS-CoV-2 spreads primarily through respiratory particles in air
✅ Keep unwell children away from school
✅ Ventilate. Monitor CO₂ to know ventilation is good. Below 800ppm is good
✅ Use HEPA filtration where needed
1/3
CO2 in an indoor space is a good measure of ventilation -- CO2 goes up when people are breathing and no fresh air is coming in.
Breathing other people's exhalations is a good way to get sick.
Here are 3 Portland performance venues. Two of them are bad. Wear a mask to protect yourself.
Breathing other people's exhalations is a good way to get sick.
Here are 3 Portland performance venues. Two of them are bad. Wear a mask to protect yourself.
October 6, 2026 at 10:45 PM
CO2 in an indoor space is a good measure of ventilation -- CO2 goes up when people are breathing and no fresh air is coming in.
Breathing other people's exhalations is a good way to get sick.
Here are 3 Portland performance venues. Two of them are bad. Wear a mask to protect yourself.
Breathing other people's exhalations is a good way to get sick.
Here are 3 Portland performance venues. Two of them are bad. Wear a mask to protect yourself.
I already have a cpap, just got it. I'll see how the appt goes in Nov (with the doc who said I was fine without 🙄)
The thing is more that my room is small and really hard to keep enough oxygen in. We got a CO2 meter, and I'm fine in the 600-800ppm interval (600ppm is like outside here)
The thing is more that my room is small and really hard to keep enough oxygen in. We got a CO2 meter, and I'm fine in the 600-800ppm interval (600ppm is like outside here)
September 19, 2026 at 10:52 AM
I already have a cpap, just got it. I'll see how the appt goes in Nov (with the doc who said I was fine without 🙄)
The thing is more that my room is small and really hard to keep enough oxygen in. We got a CO2 meter, and I'm fine in the 600-800ppm interval (600ppm is like outside here)
The thing is more that my room is small and really hard to keep enough oxygen in. We got a CO2 meter, and I'm fine in the 600-800ppm interval (600ppm is like outside here)
Australia’s coal pits can tell us a lot about the world 34 million years ago when C02 was 7-800ppm. A time when Antarctica was lush and humans didn’t exist. Same level we are headed for by 2100 or earlier.
August 21, 2026 at 9:11 AM
Australia’s coal pits can tell us a lot about the world 34 million years ago when C02 was 7-800ppm. A time when Antarctica was lush and humans didn’t exist. Same level we are headed for by 2100 or earlier.
Valla öyle yıllardır alışığız kötülüğüne ama bu sene ekstra kötü. Arıtma taktırdığım yıl 2000 ppmdi geçen arıtmacıyı çağırdım 8000 ppm, arıtılmış hali 800ppm. Hemen makineyi kapattık. 1-2 haftaya toparlanacak dediler sudan numune falan aldılar da cacık olur o iş
August 13, 2026 at 2:42 PM
Valla öyle yıllardır alışığız kötülüğüne ama bu sene ekstra kötü. Arıtma taktırdığım yıl 2000 ppmdi geçen arıtmacıyı çağırdım 8000 ppm, arıtılmış hali 800ppm. Hemen makineyi kapattık. 1-2 haftaya toparlanacak dediler sudan numune falan aldılar da cacık olur o iş
57% at 800ppm, jesus. 800ppm of CO2 was bandied about as the upper range of ‘acceptable’ for school indoor air, back when the Lab govt was still giving a shit about such things.
What is the COVID-19 airborne infection probability in an outpatient consultation with four individuals in the room ? A Japanese research team estimated this risk based on the CO2 level in the room. Calculations are also useful for measles, chickenpox, flu ...
link.springer.com/article/10.1...
link.springer.com/article/10.1...
April 16, 2024 at 9:46 AM
57% at 800ppm, jesus. 800ppm of CO2 was bandied about as the upper range of ‘acceptable’ for school indoor air, back when the Lab govt was still giving a shit about such things.
“…monitoring indoor CO₂ levels using affordable sensors can empower individuals, schools and businesses to assess the indoor air quality and adjust the ventilation accordingly. If CO₂ levels rise above safe thresholds (…800ppm), it’s time to open windows, use air purifiers…”
🎯 to bookmark, read, and share 👇
Henry Oswin and I had an article published by
@uk.theconversation.com . In it, we discuss the role of CO2 in airborne disease transmission.
Henry was the PhD student on the project, who has since graduated and is now working with Lidia Morawska down under.
theconversation.com/the-role-of-...
@uk.theconversation.com . In it, we discuss the role of CO2 in airborne disease transmission.
Henry was the PhD student on the project, who has since graduated and is now working with Lidia Morawska down under.
theconversation.com/the-role-of-...
April 17, 2025 at 2:47 AM
“…monitoring indoor CO₂ levels using affordable sensors can empower individuals, schools and businesses to assess the indoor air quality and adjust the ventilation accordingly. If CO₂ levels rise above safe thresholds (…800ppm), it’s time to open windows, use air purifiers…”
Dernier screen → 49% des infections sont asymptomatiques 👀 | Les moyens de les prévenir ✊🏼😷
3/3
3/3
May 4, 2024 at 7:02 AM
Dernier screen → 49% des infections sont asymptomatiques 👀 | Les moyens de les prévenir ✊🏼😷
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I went with SwitchBot temp and co2 sensors. The cheap sensors sale for like $32 for a 4 pack (temp & humidity) so they are just everywhere now. This is only half of them.
Just started playing with them more seriously the past couple days too! Expect nerd shit incoming.
Just started playing with them more seriously the past couple days too! Expect nerd shit incoming.
July 28, 2026 at 7:57 AM
I went with SwitchBot temp and co2 sensors. The cheap sensors sale for like $32 for a 4 pack (temp & humidity) so they are just everywhere now. This is only half of them.
Just started playing with them more seriously the past couple days too! Expect nerd shit incoming.
Just started playing with them more seriously the past couple days too! Expect nerd shit incoming.
These fossil-fuel-funded dipsticks really show their critical-thinking ignorance by only focusing on vegetable growth without telling you the obvious downsides.
600-800ppm CO2 might aid crop growth, but at what cost?
- coastal cities underwater.
- mass migrations, chaos & wars
- ecosystem breakdown.
600-800ppm CO2 might aid crop growth, but at what cost?
- coastal cities underwater.
- mass migrations, chaos & wars
- ecosystem breakdown.
February 14, 2026 at 7:36 AM
These fossil-fuel-funded dipsticks really show their critical-thinking ignorance by only focusing on vegetable growth without telling you the obvious downsides.
600-800ppm CO2 might aid crop growth, but at what cost?
- coastal cities underwater.
- mass migrations, chaos & wars
- ecosystem breakdown.
600-800ppm CO2 might aid crop growth, but at what cost?
- coastal cities underwater.
- mass migrations, chaos & wars
- ecosystem breakdown.
I initially assumed that older buildings would be bad, but by experience that theory has not held.
Our optometrist is in a medical building that appears to be similar style and age to family doc, but its ventilation has been fine (<800ppm) even in exam room with door closed.
Our optometrist is in a medical building that appears to be similar style and age to family doc, but its ventilation has been fine (<800ppm) even in exam room with door closed.
May 1, 2025 at 9:45 PM
I initially assumed that older buildings would be bad, but by experience that theory has not held.
Our optometrist is in a medical building that appears to be similar style and age to family doc, but its ventilation has been fine (<800ppm) even in exam room with door closed.
Our optometrist is in a medical building that appears to be similar style and age to family doc, but its ventilation has been fine (<800ppm) even in exam room with door closed.
I have presented this to GW transport committee in Feb/24 and suggested some easy and cost effective work arounds while engineering solutions are being developed
July 4, 2025 at 4:06 AM
I have presented this to GW transport committee in Feb/24 and suggested some easy and cost effective work arounds while engineering solutions are being developed
MoH also recommend a target of <800ppm CO2 or 5ACh for procurement of new buses and reminded Metlink of the 'Hierarchy of control measures'.
July 4, 2025 at 4:06 AM
MoH also recommend a target of <800ppm CO2 or 5ACh for procurement of new buses and reminded Metlink of the 'Hierarchy of control measures'.
Planes routinely when engines not running have horrible air quality! Rise to 2500-3000ppmCO2
over 800ppm CO2?Respirator and glasses good idea!
15% less Covid found to full time glasses wearers.
Must work for other Viruses too?
Best practice to not be sick when you get to where you are going.
👍🏻
over 800ppm CO2?Respirator and glasses good idea!
15% less Covid found to full time glasses wearers.
Must work for other Viruses too?
Best practice to not be sick when you get to where you are going.
👍🏻
May 30, 2026 at 4:21 PM
Planes routinely when engines not running have horrible air quality! Rise to 2500-3000ppmCO2
over 800ppm CO2?Respirator and glasses good idea!
15% less Covid found to full time glasses wearers.
Must work for other Viruses too?
Best practice to not be sick when you get to where you are going.
👍🏻
over 800ppm CO2?Respirator and glasses good idea!
15% less Covid found to full time glasses wearers.
Must work for other Viruses too?
Best practice to not be sick when you get to where you are going.
👍🏻
If Flying or inside.
Know the Air!
800ppm CO2 or less is good!
1500ppm CO2 you lose cognitive ability and yawn a lot!
Not great for learning.
Test the air.
Easy fix!
Out of 100’s of weddings
Open a few windows at top
Doors pegged open few inches! Under 800ppm
But if no meter?
How would you know?
Know the Air!
800ppm CO2 or less is good!
1500ppm CO2 you lose cognitive ability and yawn a lot!
Not great for learning.
Test the air.
Easy fix!
Out of 100’s of weddings
Open a few windows at top
Doors pegged open few inches! Under 800ppm
But if no meter?
How would you know?
March 25, 2026 at 7:14 PM
If Flying or inside.
Know the Air!
800ppm CO2 or less is good!
1500ppm CO2 you lose cognitive ability and yawn a lot!
Not great for learning.
Test the air.
Easy fix!
Out of 100’s of weddings
Open a few windows at top
Doors pegged open few inches! Under 800ppm
But if no meter?
How would you know?
Know the Air!
800ppm CO2 or less is good!
1500ppm CO2 you lose cognitive ability and yawn a lot!
Not great for learning.
Test the air.
Easy fix!
Out of 100’s of weddings
Open a few windows at top
Doors pegged open few inches! Under 800ppm
But if no meter?
How would you know?
Smarter in UK?
The classrooms air is better!
They monitor CO2 in each room!
Takes 3 minutes to make sure under 800ppm CO2
If not easy fix add room filters or more fresh air!
Wish we were the UK
At 1500ppm or higher you can lose 50% of brain ability! Yawning a lot!
www.hse.gov.uk/ventilation/...
The classrooms air is better!
They monitor CO2 in each room!
Takes 3 minutes to make sure under 800ppm CO2
If not easy fix add room filters or more fresh air!
Wish we were the UK
At 1500ppm or higher you can lose 50% of brain ability! Yawning a lot!
www.hse.gov.uk/ventilation/...
Using CO2 monitors - Ventilation in the workplace
Carbon dioxide (CO2) monitors can help you identify poor ventilation so you can improve it.
www.hse.gov.uk
January 4, 2026 at 7:26 PM
Smarter in UK?
The classrooms air is better!
They monitor CO2 in each room!
Takes 3 minutes to make sure under 800ppm CO2
If not easy fix add room filters or more fresh air!
Wish we were the UK
At 1500ppm or higher you can lose 50% of brain ability! Yawning a lot!
www.hse.gov.uk/ventilation/...
The classrooms air is better!
They monitor CO2 in each room!
Takes 3 minutes to make sure under 800ppm CO2
If not easy fix add room filters or more fresh air!
Wish we were the UK
At 1500ppm or higher you can lose 50% of brain ability! Yawning a lot!
www.hse.gov.uk/ventilation/...
Add glasses. 15% less Covid to glasses wearers!
Plane air is that bad!
When engines not turning the CO2 spikes past 2000ppm easy!
800ppm or less is recommended!
Plane air is that bad!
When engines not turning the CO2 spikes past 2000ppm easy!
800ppm or less is recommended!
December 30, 2025 at 1:41 PM
Add glasses. 15% less Covid to glasses wearers!
Plane air is that bad!
When engines not turning the CO2 spikes past 2000ppm easy!
800ppm or less is recommended!
Plane air is that bad!
When engines not turning the CO2 spikes past 2000ppm easy!
800ppm or less is recommended!
Told him portable CO2 NDIR sensor meters were recommended systems monitoring not recommended! Test fully occupied!
I used to fire alarm sprinkler test my schools!
Would find fusible kinks in ducts failed! Supply duct dampers closed but not in trouble!
800ppm CO2 max and 5ACH a must! 6 is better!
I used to fire alarm sprinkler test my schools!
Would find fusible kinks in ducts failed! Supply duct dampers closed but not in trouble!
800ppm CO2 max and 5ACH a must! 6 is better!
October 20, 2025 at 8:55 PM
Told him portable CO2 NDIR sensor meters were recommended systems monitoring not recommended! Test fully occupied!
I used to fire alarm sprinkler test my schools!
Would find fusible kinks in ducts failed! Supply duct dampers closed but not in trouble!
800ppm CO2 max and 5ACH a must! 6 is better!
I used to fire alarm sprinkler test my schools!
Would find fusible kinks in ducts failed! Supply duct dampers closed but not in trouble!
800ppm CO2 max and 5ACH a must! 6 is better!
Schools are failing! 800ppm 5 Air Exchanges an hour? Nope
Checking rooms occupied with a CO2 meter? Nope!
If you do not test you are all good!
Most schools low bid contractor!
Not a Reader or believer of the ASHRAE.org
Guidelines!
1500ppm u lose up to 50% cognitive ability! Great for learning?
Checking rooms occupied with a CO2 meter? Nope!
If you do not test you are all good!
Most schools low bid contractor!
Not a Reader or believer of the ASHRAE.org
Guidelines!
1500ppm u lose up to 50% cognitive ability! Great for learning?
Home | ashrae.org
Learn more about Home at ashrae.org
ASHRAE.org
October 20, 2025 at 5:39 AM
Schools are failing! 800ppm 5 Air Exchanges an hour? Nope
Checking rooms occupied with a CO2 meter? Nope!
If you do not test you are all good!
Most schools low bid contractor!
Not a Reader or believer of the ASHRAE.org
Guidelines!
1500ppm u lose up to 50% cognitive ability! Great for learning?
Checking rooms occupied with a CO2 meter? Nope!
If you do not test you are all good!
Most schools low bid contractor!
Not a Reader or believer of the ASHRAE.org
Guidelines!
1500ppm u lose up to 50% cognitive ability! Great for learning?
800ppm is recommended
And 5 Air Exchanges an Hour! Planes are bad whenever engines are not turning!
And 5 Air Exchanges an Hour! Planes are bad whenever engines are not turning!
October 20, 2025 at 5:34 AM
800ppm is recommended
And 5 Air Exchanges an Hour! Planes are bad whenever engines are not turning!
And 5 Air Exchanges an Hour! Planes are bad whenever engines are not turning!