Authors,

Thank you for your submission to Atmospheric Chemistry and Physics. I am pleased to accept the manuscript for publication. I appreciate your thorough responses to each referee, and I am confident that the manuscript has been improved during the process. I have listed a few very minor technical points below to consider before submitting the final version, but otherwise it is ready for publication.

Best regards,

Alex Huffman

Technical points:
1) Figure 2 requires slight improvements. In particular, the sizes of the panels are different, which should be corrected. The font size of the legends are also too small to read easily.
2) In the caption to Figure 2 and many of the other figures the caption text reads "Soils are ... and (f) kaolinite." While I understand that you mean that you compared several soils and also (pure?) kaolinite, the caption text is somewhat misleading on this point. I suggest adding "pure" before kaolinite as one possibility, or otherwise adding a slight change to disambiguate.
3) The color contrast in the image (Fig. 10d) from the differential interference contrast microscopy is not discussed. The image is tantalizing, but without any comment about why the red and blue regions appear isn't mentioned. Could you add to the text a statement about what these colors likely mean here?
4) The Manitou Experimental Forest is not referenced. You might consider adding Ortega et al., 2014 to page 3, line 11. In addition to this, my understanding is that the research area is officially called the "Manitou Experimental Forest Observatory (MEFO)." You may add the additional word 'Observatory' or may choose not to if you feel it is currently more accurate.
Ortega et al., ACP, 14, 6345-6367, doi:10.5194/acp-14-6345-2014, 2014.