Noronha R.I.
Bibliographic info:
Jnl. Inst. Heat. Vent. Eng. vol32 p348-349

Proposes a method for measuring the rate of air change in factories using ammonia as a tracer gas and measuring its rate of decay by a colorimetric method. The advantage is that extremely small quantities can be detected. The method is cheap, easy to use, reasonably accurate and unobjectionable to the occupants.