exhalation(redirected from Passive expiration)
Also found in: Dictionary, Thesaurus, Medical, Legal, Financial.
The process by which radioactive gases escape from the surface layers of soil or loose rock, where they are formed by decay of radioactive salts.
The giving off or sending forth in the form of vapor; expiration.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.