Li et al. present vertically resolved VOC and oVOC measurements from Beijing, China. The measurements were taken in a 325 m tall tower switching between several heights from near the surface (5 m) to the top of the tower (320 m). The authors then use these measurements to model and calculate a variety of atmospheric parameters including OH reactivity, photochemical ozone production, and vertical gradients in VOC concentrations.

While the analysis performed is not necessarily novel, the authors present fresh measurements and thorough analysis which contributes to our understanding of vertical VOC distributions and the role of boundary layer dynamics and vertical mixing in ozone formation which is desirable.

One of the most important conclusions of the article is the importance of oVOCs at higher altitudes and their ability to contribute to ozone formation which can then affect surface concentrations. Only 35% of the PBL ozone is produced in the first 320 m. The measurements and analysis are sound and support the conclusions of the paper. 

The article is well written and properly referenced. I believe the article can be published as is. However, isoprene plays a significant role in the chemistry observed and the results and yet the mechanism used to model isoprene, the MCMv3.3.1, is significantly outdated. Wennberg et al. (https://doi.org/10.1021/acs.chemrev.7b00439) published an updated mechanism for isoprene and its oxidation products. The mechanism can be retrieved at (https://data.caltech.edu/records/x88rk-wca37) and it is readily integrated with F0AM. The updated mechanism includes isomerization reactions, additional oVOCs, better representation of isoprene derived organic nitrates, updated reaction rates among many changes, which could significantly affect some of the quantitative results of the modeling work. I do not believe the overall conclusions of the article would change, which is why I support publication as is, however, using an updated mechanism would improve the analysis significantly.

Small typos:

Line 79: “the ozone formation regime like undergoes…”

Line 433: “approximately 9.5 ppb at 5 m to 5.0 m ppb at 320 m…”

This paper presented a very comprehensive vertical measurement of air pollutants and analysis of the gradient of ozone and precursors, as well as the response of vertical ozone formation sensitivity on the vertical gradients of VOC and OVOCs， this work provides a good example and new insight to understand the ozone pollution, I would like to recommend this paper publish in ACP subjects some minor suggestions.

1. Lines 27-35, the abstract is very confusing and hard to follow, I suggest the authors try to rephrase these sentences.
2. “The strong production of ozone aloft is primarily driven by high concentrations of OVOCs and hydroxyl radicals”, the OH is modeled rather than observed, thus I suggest removing OH here to make it more conservative.
3. The vertical profile of many VOC species concentrations is estimated and scaled by another site measurement as described by the SI file, I think this part would bring large uncertainty to the box model as well as the following results, I suggest the author add more discussions about the uncertainties.
4. Line 213-215, why the dry deposition rate be set to the value of 0.27cm S-1 at the surface, and the other heights set to zero?
5. Line 338-342，how are these species calibrated?
6. How about the set of HONO in the model, this is critical to the ozone sensitivity and OH field, especially since the HONO may be higher at the ground than aloft, which would decrease the vertical gradient of OH.