Dear author,

I just have two minor suggestions.
(1) In the introduction on high O3 and low CO associated with stratospheric air (page 2, line 49-52), I suggest to cite previous findings of this phenominon at Waliguan. For example, Wang et al., JGR 2006 and studes from your group. This is to show that some Chinese scientists had also studied this topic, in addition to the cited papers for other regions.
(2) On summer peak O3 at WLG (page 3, line 87-88), you may want to mention that transport of anthrogenic emission from the east may also contribute to the summer O3 ozone at WLG (e.g., Xue et al., JGR, 2011). This is to give a more complete picture on the source of summer ozone there.

Tao Wang