Ensuring that there is proper ventilation in a space is crucial for maintaining good air quality and preventing the buildup of harmful substances. Synonyms to describe having adequate ventilation would be well-ventilated, properly aired out, adequately circulated, sufficiently aired, properly ventilated, properly aired, and adequately fanned. Each of these synonyms implies that the air is moving and circulating appropriately throughout the space, which helps to remove pollutants, bacteria, and other harmful substances. Proper ventilation also helps to reduce the risk of respiratory problems, allergies, and other health issues that can result from poor air quality.