> Abundant houseplants help naturally purify the air.
apparently the effect is grossly overstated. You'd need to cram the place (in all dimensions) so tightly with plants there'd be no room for humans or furniture of any kind for any appreciable difference.
Given that the planet is not crammed in all dimensions so tightly there'd be no room for humans, and yet we have fresh air outside, I'm doubting your statement a bit.
The GP is not talking about removing CO2 from the air.
Even though no, it's not as simple as they put it, plants do remove particles from the air, humidify it, and emit plenty of stuff on their own (what may or may not be good). You don't need a lot of them to have a large impact.