The place was chosen for sampling because air masses there are unaffected by landmasses, with wind coming from the Southern Ocean.

"[2] Cape Grim was chosen as a location for sample collection because air there is transported from the Southern Ocean and is "unaffected by local pollution".

The first cylinders were originally beverage containers that were used by the US military to store breathing oxygen on aircraft during World War II.

[2][4] Samples are collected using cryogenic assisted filling (liquid nitrogen bath) under 'baseline' conditions,[3] "with winds coming from the south-west sector".

[2] After collection, every sample is analyzed and amounts of trace gases are recorded and verified with concurrent Cape Grim data.