Responses are quite detailed and answer the reviewer's questions. Two points appear to need a somewhat better response:

1. Reviewer #1 comment: "P35085, L16‐17: “Ox is used here to indicate HNO3 production, although N2O5 chemistry can also influence the formation of HNO3”: Please elaborate. It is not clear how Ox would be a direct surrogate for HNO3."

Answer is given in terms of a set of chemical reactions, but no change is made to the paper and it is still not clear why the given reactions make Ox a tracer for HNO3. Either remove the reference to Ox as an HNO3 tracer, or provide a better rationale that is included in the text of the paper.

2. Reviewer #2, comment: "Page 35070, line 10 (as well as on pages 35085 and 35086). In this and other locations in the manuscript, the importance of boundary layer dynamics is discussed. This is suppositional and based on temporal profiles of pollutants. However, some effort should be made to consider what the BL heights are, as well as their temporal dynamics. Were any soundings made? LIDAR? "

Response includes a reference to Pusede (2016) which gives specific numbers for BL height, but no change to the manuscript is indicated. These numbers should be included as part of the revised manuscript.