Thread by @DrNikkiTeran

If any conference was going to do it right it would be #CHSIAQ2022

I’m super appreciative that I can safely be in person and even sip my coffee!

That lamp kills germs that float above our heads. The building has MERV15 filters. Everyone is masked. Everyone tested this morning.

And these little lamps shine low-wavelength light that is safe for people but can kill germs.

Way to go @JHSPH_CHS

Fun facts from the speakers:

There’s a linear relationship between co2 levels and cognitive function. More co2 makes it harder to think. The same is true for particulate matter.

Clean air is good for students and employees beyond protecting against infectious disease.

Current building indoor air quality standards are design based, not performance based.

That’s like your landlord ensuring your house has a heater, but not that it still works, much less that it pumps out more warm air when it’s colder outside.

One of congress’s plans for helping to improve IAQ via improved ventilation and filtration would be done through tax credits.

R’s aren’t much in to government spending but they are against taxes, making tax credits a more palatable option.

It’s important to not overfit the improvements to our built environment to COVID.

Children are less vulnerable in this pandemic but that doesn’t mean they will be for the next one.

It’d be cool if buildings had an obvious rating for their indoor environment quality like restaurants have letter grades from the health inspector.

Live measurements would be even ideal, but right now we’ve got squat.

CFM vs CADR: Cubic feet per minute is total air moved through a device. Clean air deliver rate measures how much clean air comes out of a system.

If all of the air going through the system goes through a filter, CFM=CADR. If air can go around, CFM>CADR.

If you know the size of the room (including ceiling height!) you can calculate the air changes per hour (ACH).

The number of ACH you should have really depends on how many people are in the room.

I missed taking a photo of the slide, but the recommended number of ACH has gone down from 30 to 5 due to energy use concerns, but more would be better for preventing indoor disease transmission.

Using something like upper room germicidal UV you can get the equivalent of 100s or even 1000s of ACH equivalents.

But obviously you need to get some good air mixing.

Gotta use those ceiling fans!

“Don’t buy wine in clear bottles… even the fluorescent lights in grocery stores will denature it to some measurable level.”

New speaker is pushing back against the idea of 1000s of ACHe because air doesn’t typically mix that fast. He’s skeptical of anything over ~12 ACHe.

Zhu et al looked at how long exhaled air hung around in a space like a bus. How crowded the bus is makes a big difference.

More ACH numbers: supposedly, given how contagious BA.5 is, you’d need 31.8 ACH to (completely?) prevent transmission.