[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