air bath
Exposure of the body to fresh air, often for health or therapeutic purposes. Not a common everyday word; more likely encountered in wellness or medical contexts.
I take an air bath every morning for my health.
森林浴 is forest bathing (immersing oneself in a forest atmosphere), whereas 空気浴 is a more general air exposure, not necessarily in a forest.
Compound of 空気 (air) and 浴 (bath, bathing). The term is a straightforward Sino-Japanese coinage for the concept of an air bath.