This paper was a pleasure to read. The results are not particularly profound or unexpected, but are a very nice presentation of how to think about particle trajectories and histories. The writing is clear and straightforward and the graphics are generally well chosen to get the points across. Most of my thoughts while reading were about how nice it would have been to extend the work farther rather than about whether I trusted the reasoning. I don't actually have a lot of substantive comments.

I was a bit confused by figure 6. The legend describes panels b through d as "the time-height evolution of the column count normalized deposited particle concentration"  whereas the text described those plots as "the probability of a deposited particle’s maximum altitude reached, given a particular lifetime". I don't understand the first phrasing at all, but the second makes some sense to me.

I was surprised not to see explicit mention of an apparent pattern that the slightly unstable plots would look a lot like the unstable ones if the x-axis were T_eddy.  Yes, Figure 8 shows that some details would differ, but the overall impression is that characterizing mixing in the MBL simply with T_eddy would be useful.

I'm trying to think of to whom this information would be really valuable. After all, a sudden release of low-altitude 10 µm particles is not a common occurrence! I wind up thinking about time scales of mixing: how long after a front passage or scavenging event (a rain storm) do I have to wait before I can assume that aerosol in the mixed layer is well-mixed? How often is a a particle likely to have encountered clouds in stratocumulus or trade wind cumulus regimes? What do I need to know to make those estimations? These questions would be relevant to sampling expeditions or modeling.

Line 163--4: "The particle sizes are set to 10μm in aerodynamic diameter to represent coarse mode particles, which is much smaller than the smallest turbulence scales of the flow" Well, yes, but any realistic particle size is smaller than the turbulence scale. I expect you're referring to stopping distance for the particle being much smaller than turbulence scales or terminal velocity much less than typical vertical winds.

Equations 2 and 3: Inconsistent use of boldface to indicate vector quantities

Line 210: Is Q_* supposed to be Q₀?

Line 283: "There is a slight crossover in wind speeds at the top of the mixed layer, with neutral having a lower wind speed at 9.2 m/s, and unstable at 10.7 m/s" That crossover is at something like 30 meters, hardly the top of the mixed layer. Seems to be more at the transition between a surface layer and the bottom of the central mixed layer.

The lower x-axis in Figure 2b is paradoxical. A log scale can't go to zero. Is it linear between -10^-4 and +10^-4? That would explain the kinks in the blue and orange lines and the smooth passage through 0. Makes it hard to imagine dividing the blue lines by 10. Not sure I know of a better way to present the data though.

Figure 3: It is gorgeous, but since the w' color scale is biased, it looks like there are net downdrafts since a 0.4 m/s downdraft looks just as saturated as a 0.8 m/s updraft. Does it not work with a symmetric color scale, leaving the strongest downdrafts unsaturated?

Figure 6a: It appears that the most probable lifetime is much shorter than the 1000 s you mention. If the data are saved every 5 s, you could have shown even shorter periods at the beginning of the run. Does that not work? I'd be interested to see something like 6a, but with fraction of original particles remaining. It wouldn't have the nice dips in the unstable cases that you point out, but a flattening of the curve, so it wouldn't be as striking a plot, but would be easier to understand.

Line 593: "spatially" is missing the y

Line 627: "Even for neutral conditions, it can take over 90 minutes" implies that unstable conditions take longer! Perhaps just ditch the "Even"