Dear Authors,

Thank you for considering all 4 reviewer comments. After careful re-reading of the revised manuscript, I feel you have clearly addressed these comments. However, upon reading the newest version, I found several minor edits/technical corrections that must be corrected. Once you correct these, I'll gladly accept this for final publication in ACP.

Most sincerely, Jason Surratt

Minor Edits/Technical Corrections:

1.) Page 1, Lines 16-17: change to: "we chemically characterized OSs and nitrooxy OSs (NOSs) formed under the influence of....."

2.) Page 1, Line 18: change "The" to "A ultrahigh-resolution"

3.) Page 1, Line 21: delete the word "the' before "high"

4.) Page 2, Line 42: Insert the word "the" between "in" and "ambient"

5.) Page 2, Line 49:
Change "Many chamber experiments studied try to reveal" to "Many prior chamber experiments revealed the precursors....."

6.) Pages 2-3, Lines 49-51: Please add Surratt et al. (2007, ES&T) to this citation.

7.) Page 3, Line 51: Change ", which remain unclear" to "however, the atmospheric relevance of these remains unclear."

8.) Page 5, Line 101: Please change "environment" to "environmental"

9.) Page 5, Line 118: Should the authors consider adding ", respectively." after "..., China)" ?

10.) Page 6, Line 129: Can the authors clarify how much of the isoprene-derived OSs were not captured by your direct infusion method due to the use of SPE? I know from personal experience that when we analyzed PM2.5 samples collected from the southeastern U.S. and applied SPE, we did not detect isoprene-derived OSs (Gao et al., 2016, JGR). As a result, in Surratt et al. (2017, ES&T), we found that there were indeed present when using LC/MS and not employing an SPE pretreatment step.

Dear Authors, thank you again for submitting this work to ACP. I recommend that this be published as is. Congratulations on your contribution to the organosulfate literature! It is important to note that data such as these are needed from China.

Most sincerely, Jason Surratt