[throw0101a]

> There are so many rooms, classrooms, movie theaters and other places with poor ventilation where you just feel dizzy, or fall asleep, not knowing it was just due to lower oxygen levels in your blood. Raising awareness is the only real solution.

Not wrong, but it is perhaps worth noting that there are already standards for proper ventilation. Generally you're looking at 5–10 cfm/person (2.5-5 L/s), depending on the facility and purpose of the room; see Table 6.2.2.1 in ASHRAE Standard 62.1 for the US:

* https://www.ashrae.org/file%20library/technical%20resources/...

Maybe set up a monitor, but if the room/facility has recently been renovated and meets modern (>2013) building codes, this 'should' have already been taken into account.

[josephg]

Should…

Whenever I travel, I bring a CO2 meter with me. It’s amazing how often the air is bad. Often in unexpected places. My meter hit 3100 in an uber once. I didn’t even notice until I got to my hotel room and looked at the data log. It was a fresh, hot day outside. The uber had windows closed and AC on. I bet he had no idea - but he was driving with significant cognitive impairment. Takeoff and landing in planes are always the worst. If you get sleepy as the plane is taking off, it’s not you. The plane’s ventilation doesn’t work properly when the plane is stationary. So before a plane is in the air, they often hit 2500.

[sarchertech]

He’s not driving with significant cognitive impairment. Submarines and the ISS routinely operate at 5000 ppm. 60 years of studies and almost a century of operating submarines has shown no impairment at 5000 ppm.

Then all of the sudden Satish 2012 comes along and shows serious cognitive impairment at 1000 ppm. The only studies that have replicated this involved Satish. Studies without Satish as a coauthor fail to replicate their findings.

If you think about it for a second, the levels of impairment Satish shows don’t make sense at all. You’d expect to see differences on SAT scores of hundreds of points between test centers with good ventilation and bad. You’d expect to see massive differences between regions where AC is more or less common. Or even between seasons.

[jerlam]

Cars have a "make the air bad" button, the recirculation button. Some people always have it on. I wonder if it's a factor in road rage.

[fingerlocks]

Sounds like you need to change your cabin filter.

[dnemmers]

I think the 'make bad air' part, is that it allows carbon dioxide levels to build up...not that the air is unpleasant to the senses to breathe.

[josephg]

Perhaps a lot of people should change their cabin filters.

Air quality should be good everywhere. But its not. You can't tell if you don't measure it.

[hansvm]

Interesting. I can barely stay awake in typical commercial planes, and I always attributed it to the lower partial oxygen pressure.

[quickthrowman]

When was the last time you had that sensor calibrated properly with a can of test gas and a multimeter?

[colechristensen]

Take it outside, as long as it measures 400-450 it's probably good.

Metrology calibration is necessary if you want accuracy better than 10%, but most of us don't care at all about that, instead we care about increments of 200ppm or more.

[jameshart]

Haha yes. 400-450ppm is fine. We’re doing just fine here. Everything is okay.

https://www.co2levels.org/

[jaapz]

The comment was about the accuracy of the sensor, not about raising CO2 levels across the globe.

[jameshart]

Sure. It just draws attention to the fact that a throwaway piece of advice for checking calibration of a CO2 sensor is ‘it should read 400-450ppm outside’ when a few short decades ago that advice would have been ‘it should read 300-350ppm outside’.

It’s like if someone said ‘you can check if your chatbot’s news feed is complete and up to date by asking it for ‘recent mass shootings’. There should be two or three in the past seven days’. It’s true and a valid methodology but holy crap does it say something dark about where we are.

[ShinyLeftPad]

Local factors can make your CO2 fluctuate by 200ppm. If you're near a busy road with not a lot of wind 600 ppm is possible. But it's not that important if you open your window at 1000 ppm or 1200 ppm.

[II2II]

Building codes that address this are wonderful, however:

- Plenty of people live or work in older buildings, where are not up to standard. For example: my office probably violates the air quality sensibilities of the Victorian era, which is when it was originally built.

- Equipment breaks down, isn't operated properly, or wasn't installed correctly. Having monitors that measure air quality is an extra check. While you may not be able to get direct action upon a consumer sensor, it can help you push for action.

I've been in buildings of varying quality over the years. I've seen how it takes time to get people in to do air quality testing. Heck, I saw the government claim that the air quality was acceptable in schools during the pandemic because the schools had passive ventilation systems. That meant they could open windows. (To be fair, the air quality in most of those buildings was probably fine since that was how the buildings were designed. That said, such standards make it easy for some buildings to slip through the cracks.)

So yeah, sensors to the people!

[bloomingeek]

And let's not forget unscrupulous building owners/renters who will not employ the at least 10% fresh air intake rule on their HVAC system. This fresh air is outside air temperature, so their system has to change it's temp according to the thermostat setting, which costs money.

[account42]

Fresh air doesn't have to be outside temperatures as you can heat exchange most of the energy from exhaust to intake without putting in additional power.

[bloomingeek]

True, but the vast amount of buildings don't have this technology.

[xyzzy_plugh]

This is correct, but there's still a lot of opportunity to do better.

I've been involved with the build out of several office spaces in new and old buildings. We always took this sort of thing seriously and measured each room independently for a week (many at a time) ensuring we accounted for periods of high occupancy.

This let us tune the HVAC systems to operate more efficiently, ensuring comfortable temperatures and air circulation. Every time I've seen this done there were structural deficiencies that required remediation, some times it meant adjusting duct work.

Most modern office buildings are designed to be a platform for constructing spaces, as spaces usually evolve and change between leases and tenants. They're designed to accommodate this sort of thing.

However I've found that no build out nails this the first time. It's very hard! Often times things look fine but once you get people in the space things change drastically. It requires time and effort to address.

Several of my offices had such good air that I'd prefer being there over pretty much anywhere else -- even outside on poor AQI days.

I've also found that a lot of offices don't do any of this and their air quality is noticeably poor. And lastly I've found that the oldest buildings, including schools -- and I'm talking really old -- have very good air because they are so incredibly leaky. They're usually harder to cool and heat, though.

[wouldbecouldbe]

I think modern domestic houses its the opposite. At least in Netherlands insulation is such a strong focus, due to climate change I think, that modern appartments have terrible ventilation

[hydevito]

Stayed at a beautiful new house in Finland, with five people instead of the usual two, the CO2 detector intermittently went off while we were sleeping. Which the hosts assured us was a faulty detector. They also spoke to how extremely energy efficient the house was, to us it seemed like there wasn't enough ventilation, to improve the insulation. Against their wishes, I slept with all windows fully cracked, which was only ~2 inches due to the "efficient" design.

[pieterhg]

This was probably CO not CO2? A CO2 monitor doesn't "go off", it just silently reports. CO would go off because it's deadly to have a CO leak.

[317070]

My portable CO2 monitor goes off. You can set a levels of warning on the aranet. It is a very quiet, non-disruptive alarm, but an alarm nonetheless.

I agree with OP. I don't always carry it along, but it has been a massive boost to my productivity.

[jltsiren]

Poor ventilation is mostly an issue in homes built or renovated in the 1970s, when the oil crisis led to ill-considered efforts to save energy. New homes typically achieve energy efficiency by using heat pumps in the ventilation system.

[OptionOfT]

How modern? We built or house in Belgium in 2016, and it was completely sealed, very well insulated, but the air quality was good because we had mechanical ventilation. Clean air blown in, stale air extracted which then went through a heat exchanger.

The only issue this house had was it overheated. We had glass facing south. Even in winter it instantly became too hot.

[throw0101a]

> I think modern domestic houses its the opposite. At least in Netherlands insulation is such a strong focus, due to climate change I think, that modern appartments have terrible ventilation

The link I pointed to is all about ventilation, so just because people ignored an important component of building science, and focused on one aspect, does not invalidate it.

And while climate change is important and using efficiency to deal with it is useful, the thermal control layer is actually the least important of the four:

* https://buildingscience.com/documents/insights/bsi-001-the-p...

'Bulk' water (precipitation) and moisture can cause deterioration of the building materials (rot, crumbling), and also mold, which has its own health effects. Leaky houses can often blow conditioned air at much faster rates than thermal leakage.

[avhception]

A friend of mine recently moved to a modern apartment, built only a few years ago to a very high isolation standard (Germany). I stayed over night and slept on his couch, the air got really really dry and stuffy. It was really uncomfortable.

[HPsquared]

Heat recovery ventilation is the answer to this. You also get the benefit of being able to filter it.

[throw0101a]

Energy recovery ventilation is the answer to this.

HRVs only deal with temperature, but then you have humidity that is non-controlled: moisture coming in during the summer, and getting vented out in the winter (too-dry air coming in).

ERVs handle both.