indoor walls and ceiling (Web picture)
The truth is that these walls emit toxicity at various levels. Silent, silent, but dangerous. Building materials, wall primers and paint , have improved over the years; and yet we're constantly advised, and rightly so, to keep windows slightly open during most of the year.
(Air conditioning, which requires closed windows and doors for its efficacity, has worsened things for many people, including me, causing various allergic reactions and dry skin).
I don't trust any wall stuff. We don't really know what's in it despite regulations. The use of lead in paint ( lead - a metal that can be very toxic) was banned in 1978, but it still exists in walls of older homes. Asbestos (silicate minerals)- based materials, are banned in most countries and yet they are not completely out of use.
The bottom line - we should keep the windows open (not all the way, just a few inches) for as long as possible. Of course, not during the night or in very nasty weather.