通気

通気

Ventilation.

Here, '通気' is used to describe the general airflow or ventilation within a space (the room).

部屋の通気が悪いので、窓を開けて空気を入れましょう。

The ventilation in the room is poor, so let's open the window to let air in.

In this sentence, '通気性' specifies the breathable quality of the material, indicating how easily air can pass.

この素材は通気性が良いため、汗をかいても快適です。

This material is breathable, so it's comfortable even when sweating.

Here, '通気' is used to refer to a system pertinent to airflow or ventilation, such as an architectural or technical aspect.

新しい通気システムを設置して、より良い空気環境を作りましょう。

Let's install a new ventilation system to create a better air environment.