ventilation

noun

1. the act of supplying fresh air and getting rid of foul air
2. a mechanical system in a building that provides fresh air"she was continually adjusting the ventilation"
3. free and open discussion of (or debate on) some question of public interest"such a proposal deserves thorough public discussion"
4. the bodily process of inhalation and exhalation; the process of taking in oxygen from inhaled air and releasing carbon dioxide by exhalation