Hi all. Thanks so much for responding to all of the reviewers comments. Im very happy to proceed to publication once a minor detail has been dealt with. In the code availability policy found here: https://www.geoscientific-model-development.net/for_authors/code_and_data_policy.html We have a summary that states:

"Preferably, this section should contain the instructions for obtaining the model code and/or data, either from the supplement or from an archive with a digital object identifier (DOI). Suitable repositories can be found at the Registry of Research Data Repositories, e.g. ZENODO for model code. After the paper is accepted, a link to the GMD paper should be added to the metadata of the archive.
Although not recommended, and authors will typically be requested to improve on this, it is also possible to provide the code and/or data only upon request via a given point of contact.
If the authors cannot or do not wish to make the code and/or data public (e.g. copyright or licensing restrictions), the reasons must be clearly stated. Note that, for the purpose of the review, topical editors and referees must still be given access to the code and/or data (whilst preserving the anonymity of the referees)."

we need a little more information than the text now given: 'Upon completion of expanded user testing, the CMAQ Adjoint code will be hosted and distributed by the U.S. EPA. ' Can you please expand using the above guidance?

Cheers
Dave

Hi there. Many thanks for your minor revisions. We are good to go now...many congratulations!!