Interactive comment on “Mixing State of Refractory Black Carbon of the North China Plain Regional Aerosol Combining a Single Particle Soot Photometer and a Volatility Tandem Differential Mobility Analyzer” by Yuxuan Zhang et al

The article by Zhang et al. retreads a lot of information already covered in Zhang et al. (AMT, 2016), with some additional analysis. Overall, I find there are potentially some interesting components of this paper that go beyond the authors previous work, but at the same time there are a number of aspects that are presented as novel insights that are either not sufficiently justified or explained, or are simply wrong. I cannot recommend this paper for publication. The authors should work to truly distinguish it from their previous work. My specific comments follow below (in chronological order, mainly).