the.com/mustiness
The smell of time getting comfortable in places fresh air forgot.
means A stale, damp, slightly moldy odor that builds up in poorly ventilated or long-closed spaces.
from From must, the stale-air sense rooted in moist and Latin mustum, the young unfermented wine that, left alone, quietly soured into something less charming.
Actual culpritMicrobes called geosmin and 2-MIB off-gassing.
Nose nerdHumans detect geosmin at five parts per trillion.
Old booksThat beloved smell is paper slowly decomposing.