Text this: Tracer gas measurement of airflow rates in spaces with several air-handling units, recirculation, or large time constants

  _  __     ___      ____      _____    _    _   
 | |/ //   / _ \\   |  _ \\   |  ___|| | \  / || 
 | ' //   / //\ \\  | |_| ||  | ||__   |  \/  || 
 | . \\  |  ___  || | .  //   | ||__   | .  . || 
 |_|\_\\ |_||  |_|| |_|\_\\   |_____|| |_|\/|_|| 
 `-` --` `-`   `-`  `-` --`   `-----`  `-`  `-`