The concept of the tracer gas leak test system is to trace escaped gases that exist at a low concentration in the atmosphere. Tracer gas leak testing method is typically used for refrigerant, hydrocarbon & other gas analyzers.
Tracer gas tests (SF6. etc.) are very useful to determine the ingress or out-flow in-to or out -of the atmosphere under study, even at very low leakage rates.
Atmospheric air (O2, N2, CO2, etc) do not vary appreciably; if you use a gas that is not present in the system being studied, you can obtain very sensitive results.
Further, in real time implementation the atmospheric air is the medium. shall i do the research with atmospheric air. if i used what will be problems would i face.