These literal "green walls" act as both filters and central aesthetic features of buildings. They're centrally controlled via the building's HVAC system, pulling air through the walls regardless of whether or not the system is in operation.
The natural air filter removes VOCs and CO2 from the air as it passes through the wall into the building's office spaces.
For an amazing 3D graphic of the system in operation, check out this link.
I was slightly sceptical about the necessary size application needed for industrial structures, but it looks as if Naturaire has every base covered:
Given most residential and office conditions, a ratio of at least 1 to 100 for the area of the biofilter to floor area to be treated will give desired affect. Given typical operating conditions, this will mean that one square metre of biofilter will treat 100 square metres of floor space (or 1 square foot of biofilter will treat 100 square feet of floor space). This will give the desired improvement to the indoor environment.
The majority of this post comes via the Queens University Live Building virtual lab. There is a TON of information available at their website and I encourage you to take a gander for yourself.