What is an efficient ventilation system? Vad ar ett effektivt ventilations system?

Notes that there is currently no generally accepted term for the efficiency of a system in terms of pollution removal. Different proposals have been suggested. There is now sufficient factual data to determine the difference inability of different systems to evacuate pollution. This is despite the factthat the requirement for minimum flow is the same for all fan-assisted ventilation. The requirement is also unrelated to whether the system is an extract or push-pull system and where the ventilation devices are positioned.