[whatevertrevor]

As pointed out in another comment HEPA filters don't work well for VOCs (Volatile Organic Compounds), which are gaseous in nature. They're intended to filter particulate matter.

For VOCs you need activated charcoal/carbon filters usually and replace them from time to time.

[jopsen]

Or a ventilation system I'm guess?

Where I live all new houses are pressure tested and have a ventilation system, replacing all air once every 1-2 hours or something (I think).

[sneak]

TFA is specifically about how they attach to porous surfaces and how simple ventilation is way less useful than originally assumed.

[whatevertrevor]

The GP comment is talking about active ventilation though, through an ERV/HRV system. Also the article states this:

> The lifetime of these compounds indoors can be extended via partitioning to the surface reservoir as modulated by ACR. Higher ACR, which may be achieved by opening windows or through mechanical ventilation, leads to shorter t_half_surf because once indoor compounds partition from the surface reservoir to the gas phase as controlled by gas diffusion across the boundary layer, they would be removed from indoor air more quickly before repartitioning to the surface reservoir.

So they do state active ventilation can help, as you reduce the vapor pressure of VOCs allowing them to partition back into the gaseous env, where they can be promptly ejected. How much exactly is hard to ascertain from their graph since I don't have the exact data they used in the plots. But from squinting at it, it seems 1 OOM change in ACR gives you close to 1 OOM change in the VOC half life, which seems substantial to me.

So adding an active ventilation system might be a good idea for this particular concern. Of course it will add to your energy bill.

[jopsen]

Modern ventilation systems, like the one I have will recover a lot of heat, when exchanging air.

[whatevertrevor]

I know, I have one too. It's still energy negative because they're not 100% efficient and you're paying energy to run them in the first place.

Still worth it for better air quality.

[fuzzfactor]

True, but simply using a low volume exhaust like a bathroom fan can give you a phenomenally greater effect than zero.

And that's for the entire house, zero is such a small number.

Then when you run it 24/7 it's 24 times as effective compared to a single hour. That's an impressive multiple itself, on top of bumping the baseline above zero to begin with.

This can really add up to a lot more ventilation than commonly assumed from some of the crummiest fans.

If you can't tell the difference when you walk in, between zero and running one of these all day before you get there, you're gonna need a bigger fan.

But you may be surprised and you never know until you try.

[jopsen]

But when stuck inside the porous surfaces isn't the problem mostly when they become airborne again?

Most of us don't eat wooden furniture -- granted my toddler didn't get the memo :)

Thus, continuous ventilation (while not perfect) is hopefully still a decent alternative. Probably better than active charcoal filter.

Granted I should probably out a charcoal filter on the ventilation intake to reduce pollutants coming in from nearby traffic. (All depending on your level of paranoia)

[whatevertrevor]

If the porous surfaces are saturated then you'll basically be maximizing the vapor pressure of these gases in the air you breathe. Check out my sibling comment, extrapolating just from the data in the article an active ventilation system should help.

EDIT: And yes, charcoal filters aren't as effective if they're not part of your critical airflow/ventilation path. :D

[Gigachad]

Every air purifier I’ve seen has both a hepa filter and carbon filter.