Technical comments attached: Jia et al....

This is an important paper. CHBr3 is a potent ODS and is produced in substantial quanties in the production of seaweed supplements to the diets of ruminants to suppress their CH4 production. If adopted widely, this technologhy could substantially reduce ruminant CH4 emissions which are a significant component of global CH4 emissions. The paper address the important concept for short-lived ODSs that the impact on the ozone layer is dependent on the location of the emissions. The paper demonstrated the production of the necessary supplements to feed the global ruminant levels does not significantly deplete stratospheric ozone - the technology is 'ozone safe'.

I have a technical issue with the assumed/calculated levels of CHBr3 resulting largely from coastal regions and natural seaweeds. I think the Zafra et al. data, which are a compendium of CHBr3 data from several laboratories, and are not intercalibrated (Zaffra et al. recognize this problem and have indicated it will be addressed in future studies) and potentially underestimate background levels of CHBr3 in coastal regions. This seems to be the case in Tasmania (one of the study regions) where measured bachground CHBr3 levels from the AGAGE program (not part of the Zaffra data, but arguable the best measured/calibrated CHBr3 data set available) seem to be up to a factor of 3 higher than the Zaffra et al. data. Is this important? - the authors need to address this.

The authors need to review information on CHBr3 atmospheric lifetime data and ozone impacts in the latest (2021) assessments of climate change (IPCC) and ozone depletion (UNEP) 

The paper presents modeling experiment to evaluate how one of the proposed feeding management alternatives to reduce CH4 emissions from ruminant livestock (i.e., Aspargopsis farming) could impact on the stratospheric ozone layer due to the by-product formation of  bromoform (CHBr3). This species is a very short-lived species (VSLS) with a mean lifetime of 17 days in the atmosphere, and consequently, the CHBr3 impact on stratospheric ozone depends on the superposition of source strength and location with the efficiency of convective transport. The paper propose a multiple set of realistic local and global scenarios, as well as the occurrence of some improbable extreme episodes affecting the Australian coast, to evaluate a representative range of the overall ozone depletion potential (ODP) of bromoform emissions from oceanic and terrestrial cultivation approaches, and compare them with the impact of coastal natural bromoform emissions. The work is very well-planed and provides a realistic and clear evaluation of the magnitude of one of the environmental consequences of promoting Aspargopsis production in Australia, and determine that even in the worse possible scenario, the negative impact of the additional farming-released bromoform are very small in comparison with the natural contribution from the ocean. The methodology and results are generally well presented, although some clarification is required as described below. I suggest the paper is accepted for publication after the issues/comments in the attached file have been solved.

Jia et al. presented a modeling analysis on the potential environmental impact of bromoform from Australia Asparagopsis farming on atmospheric ozone depletion.  This is an interesting environment impact analysis, and the results would be of great interest to the Asparagopsis farming community and some environmental policy makers in Australia. Overall, the experiment is adequately designed, and the paper is well written, and should be accepted for publication on ACP. I have only some very minor comments.

1. Change “long-lived halogens” to either long-lived halogen-containing compounds or long-lived halocarbons. ODP is not defined for long-lived halogens. 
2. ->varies, depending on
3. -> emitted into the atmosphere
4. Here and later in the text: To cite the WMO assessment chapters, you should use “Engel and Rigby et al, 2018”
5. I would recommend rephrasing of “the aim of this study was elucidation of …” to “… to assess the impact/contribution …”. Elucidation seems to be too much of an assertion in the context of this paper.
6.  an effective
7. L305-307. Is there a published reference for trajectory-based ODP? Brioude et al. (2010) and Pisso et al. (2010)??
8. L326 & L329. May be this is a personal habit thing, but I would prefer “the OPD values applied here” and “the comparison presented here”
9. L520, 527, 532, 542, CHBr”3” should be subscript.