This study makes a full investigation about connection between snow cover/EU teleconnection and O3 pollution in north China. The April-May snow cover in West Siberia was proposed as a preceding climate driver that influenced the summer surface O3-related meteorology in North China during 1980–1998, and the associated physical mechanisms were also explained by comparing the periods before and after the mid-1990s. The results of this study could provide a reference for the seasonal prediction of O3. This paper is well written and organized. I recommend it to be published in ACP after several minor corrections.

1. Based on the content in the main text, the O3-related meteorology (OWI) is focus on summertime. I would suggest to clarify the specific season in the title, which will give a more direct expression about the seasonal prediction mechanism.
2. The high level O3 concentrations before mid-1990s are considered to be connected with the positive phase of EU teleconnection. While, after mid-1990s, the northward shift of snow cover results to the insignificant connections between snow anomalies, EU pattern and O3. What is the possible reason for the change point of mid-1990s? That is, why 1990s was selected as the turning point in this study. Is it based on the statistical analysis or some physical mechanisms?
3. Some detailed information about the calculation of OWI index in Line 105 are suggested to add. E.g., how to normalize the meteorological variables. The absolute value of observed O3 concentration and OWI should be included to indicate the robust of OWI.

Yin et al. examined the possible impacts of snow cover over west Siberia on Eurasia teleconnection and ozone pollution meteorology in North China at the decadal timescale.  They found that 1980-1998 changes in snow cover over west Siberia could modulate ozone pollution weathers over the North China through affecting the Eurasia teleconnection, but after that this connection tends to be insignificant. They also demonstrated that snow cover as well as sea ice could be the effective predictors for ozone pollution meteorology over the North China.

Overall, this is a timely study with interesting results. It fits well within the scope of ACP journal. I hope it can be published in the near future while the following concerns should be addressed.

Fig3a: There is no doubt that snow cover over west Siberia is linked with ozone pollution in North China. However, I am wondering if OWI and SC_ws are still significantly correlated over 1980-1998 if the authors remove the 1997/1998 El nino years, which could have driven these evident interannual anomalies at a large scale. Similar question also for correlation between NHFws and EU/OWI in Fig.6a.

L97: Is Yin et al. (2020a) the first one to devise the EU index? If not, the original reference should be added.

L111-112: I don’t think winds at 10m can be used to represent the transport from Yangtze River Delta to North China. Moreover, lifetimes of O3 precursors are generally within a few hours in summer. Any reference to support this argument?

L113: Rain shouldn’t be effective to remove ozone. You also confirmed this in L127.

L130-132: How about emissions outside of China? Are they fixed at a certain year or changing over time?

L141&L217: The subtitles are not clear.

L169&Fig1c: Why is ozone strongly enhanced over the whole domain? There should be weak ozone formation over the high-latitude region with few emissions.

L211-212: Should be corrected.

L218: Please add “of” before “how to…”.

Discussion: Further studies using climate-chemistry model to verify the role of snow cover should be highlighted.