Halogenated compounds as gaseous meteorological tracers.

Reviews use of tracer compounds to demonstrate the transfer of pollutants from one local area or city to another. A study of gaseous compounds resulted in the selection of three suitable materials:sulphur hexafluoride, bromotrifluoromethan andOctafluorocyclobutane. These materials are all non-toxic, rare in the atmosphere and can be readily dispersed from tanks.Describes two systems developed to detect tracer gases. Sensitivity of 10-5 p.p.m. was achieved for sulphur hexafluoride without concentration of the sample. Gives method for collectingair samples and analysing them.