Following the comments from the two referees and the detailed responses from the authors this paper should be published following further minor revisions. The results are important and interesting for scientists working on sampling and measurement of halocarbons, and this manuscript will provide a basis for further work and publication of results from halocarbon measurements using HIRES.

There are some further points to consider in a revised manuscript:

1) "Whole" should be removed from the title as this is not strictly true. I would suggest "Stability of halocarbons in simulated air stored in stainless steel canisters"
2) P2 L 32 - spell out which GHGs it has been used for to save confusion with halocarbons as GHGs
3) P3 L15 - more details on the molecular sieve needed and conditions under which this is done. What is removed in this step?
4) Can you relate Figure 1 to Figure 2? The valves in Fig 1 are the valves labelled g in Figure 2. From Figure 2 there doesn't appear to be any references to the lettered labelling of the valves. If this is the case please remove unnecessary letter labelling from the figure.
5) Page 6 line 19 - use "L", not "l" - check throughout
6) In relation to possible blank issues (initially raised in relation to the AC system) - were lab blanks measured as routine throughout this test period?
7) P7 L21 and elsewhere - there is description of the plotting detail within the actual text. This should be clear from the figure caption and the legend. Particularly on page 9 line 27 where colours are mentioned - some readers won't be able to connect a colour to a description e.g. I think this looks more orange than brown!
8) I think it would be good to reiterate in the figure caption of Fig 4 the difference in how sampling was done between the short term and long term experiments (different canisters or same canister). If the reader hasn't read the text they can then instantly make sense of the results.
9) Why were % changes removed in Table 1? Given lack of supporting data these numbers might be quite informative? Table title needs changing if numbers removed.
10) The last paragraph could do with more explaining e.g. welding under vacuum. Is this different to before and why is this an improvement? Will there be any opportunities to do a new set of tests with the new canisters any time soon?
11) Given point 10 can ore detail be provided on the origin of the canisters used here? This detail is given in response to the reviewer 2 but not in the revised text
12) In reply to reviewer 2 you explain why these tests are difficult to repeat. Some mention of this in the text would be worthwhile. It sounds like you really made the most of a period when the sampler was on a break from flights.

Well done on a producing a very thorough piece of work to quantify the stability of halocarbons in your sampling system. The minor improvements made after review are appreciated and make clearer the results of this important work.