[enginoor]

The common term is "pneumatics" and the components are prevalent in all automation and manufacturing. The air required is typically compressed on site.

Pneumatic actuators are relatively inexpensive, have a binary state that is easy to control, and offer a high power density.

[laurent92]

How do they avoid bacteria/mould from growing in tanks and flocking the pipes and releasing in the room? Do such systems ever get cleaned up?

[HPsquared]

The air in industrial pneumatic systems is filtered and dried, which would prevent these issues.

Pneumatic systems often use small orifices and valves to control the air flow which would be quickly clogged by any debris, so cleanliness is important.

An aside: PID control was, back in the day, mostly implemented in pneumatic control systems (using a set of levers, bellows springs and nozzles). Pneumatic control systems were (and still are) used a LOT in industrial control systems where e.g. flammable environments where electrical equipment is too much of a risk.

https://control.com/textbook/closed-loop-control/pneumatic-p...

[diarrhea]

Mechanical, i.e. pneumatic, PID controllers were one of the most incredible things to learn about in university.