Dear authors,

I have walked through your responses and changes to the comments by the reviewers. They are generally adequate and have improved the manuscript. I do, however, agree with one of the review comments that it would be better to link the source contribution to the health risks. Specifically, the Section 3.4 currently is still mostly about source contribution; it would be nice to have a bit more discussion on how different emission sources would lead to different health risks.

In addition, a few more minor comments for you to clarify/consider, as below.

1) What was the criteria to choose 10 degree C to separate cold and warm seasons?

2) If size segregation is something that distinguishes this study with most of other similar studies in literature, would it be better to reflect it in the title? For example, adding “revealed by size-segregated measurements” at the end of the title?


3) A few more minor points/typos:

L323 (in track-changed file): suggest to add “was” in front of “partly”.

L428: “dominate” should be “dominating”.