This study investigated the different impacts of short duration (SD) and long duration (LD) El Nino on the aerosol pollution in China. The authors found that SD El Nino exerts more significant influences on the PM2.5 concentrations in winter, which increase in northeastern and southern China and decrease in central-eastern China. The anomalous atmospheric circulation induced by SD El Nino is the dominant reason for PM2.5 concentration changes. These findings are interesting and useful to air quality prediction and improvement. The logic of this article is good. However, there are some major concerns about the physical mechanism that I doubt. The comments below that I expect are helpful for improving the manuscript.

Major comments:

1. The anomalous atmospheric circulation induced by El Nino plays a vital role in changing the PM2.5 concentration distribution. The authors should give the observed atmospheric circulation conditions induced by SD and LD El Nino using the reanalysis data. Then, the authors can compare the observed atmospheric circulation with the simulated circulation, and can further evaluate whether the model simulates a reasonable atmospheric circulation. This check is very important, because atmospheric circulation induced by El Nino determines the conclusion of this study.
2. It is known that the anticyclone over the western North Pacific is the key atmospheric circulation system that El Nino exerts its impact on East Asia. Certainly, the southeasterly winds on the western side of this anticyclone lead to increase of the PM2.5 concentration. However, the authors reported that the decrease of the PM2.5concentration in central-eastern China is attributed to the anomalous northerly winds of the cyclone over the East China Sea (Figure 7a). This anomalous cyclone is rarely reported. I doubt whether this anomalous cyclone indeed exists in observation, or it only appears in simulation? So, I suggest the authors should check the observational circulation condition using the reanalysis data to verify the simulated result.

Minor comments:

3. Please pay attention to the singular and plural in English grammar, for example:

Line 45, “have” should be changed into “has”

Line 77, “have” should be changed into “has”

Line 170, “is” should be changed into “are”

Line 188, “are” should be changed into “is”

4. Line 172-176, please rewrite this sentence
5. Line 191, plus “anomaly” after “SST”

As mentioned in the review of this article, many scholars have conducted the relevant studies on the impact of El Niño events on winter aerosol pollution over China. However, there are some uncertainties in those studies and thus it is necessary to continue to carry out In-depth research to reduce the uncertainty. The ingenuity of this research is that the classification method is distinguished according to the life cycle (i.e. SD and LD) method instead of the traditional El Niño such as intensity, CP or EP of the El Niño. So this study is very meaningful, but it can still be further improved in the following aspects:

1. The author can try to discuss the relationship and difference between the SD and LD classification methods and the intensity classification in previous studies or the CP and EP classification.
2. Although the authors focused on the analysis of events in different seasons throughout the year when distinguishing between the SD and LD types of El Niño, when studying the impact of different types of El Niño on aerosol pollution, DJF is selected as the researched season, so I recommend the title of this article should be revised to Intensified modulation of winter aerosol pollution in China by El Niño with short duration.
3. Previous study has shown (Sun et al., 2018) that GCM models have certain limitations to capture climate anomalies generated by El Niño, so there are usually some inconsistencies between the simulation results and the observation results. It is recommended that the author face up to these problems and discuss the uncertainty of the study.

Reference:

Sun, J., Li, H., Zhang, W., Li, T., Zhao, W., Zuo, Z., Guo, S., Wu, D., and Fan, S.:Modulation of the ENSO on Winter Aerosol Pollution in the Eastern Region of China, J. Geophys. Res. Atmos.,123, 11,952-11, https://doi.org/10.1029/2018jd028534, 2018.

Title: Intensified modulation of aerosol pollution in China by El Niño with short duration

The El Niño (ENSO) is an irregular periodic variation in sea surface temperature in the tropical Pacific Ocean, affecting the Walker Circulation and displacing the convective area. It can lead to significant anomalies in atmospheric general circulations and weather conditions, which may further impact on haze pollutions in China. In this article, authors used the state-of-the-science Energy Exascale Earth System Model version 1 (E3SMv1) to estimate the impacts of El Niño with short and long durations on PM_2.5 during winter in China. They further investigated underlying mechanisms of PM_2.5 variations controlled by ENSO-related circulation and precipitation changes. The results are helpful to improve the understanding of modulation of aerosol pollution in China by El Niño over the study region. I think the manuscript can be accepted after the following concerns are addressed.

General Comments:

1. The Introduction should be more concise. The authors should work further to reduce the main text to exclude any unnecessary contents like “clean air actions”, and explain how spatiotemporal variations of aerosol in China controlled by ENSO-related changes in not only in wind speed and precipitation, but Walker Circulation and convections as well in more detail.
2. The authors intended to show the difference of El Niño with short and long durations in section 2.2, where the background climates are quite different. Thus more discussion on their difference in climatological means (e.g. general circulation, temperature, precipitation, humidity and wind) are recommend.

Minor suggestions:

1. Line 92, “Based on haze day counting mainly using atmospheric visibility, many studies found” may be replaced with “Many studies counted haze days based on atmospheric visibility and found”.
2. Line 96, “several studies … from satellite retrievals”. Insert some references there.
3. Line 141, “… have different impacts on the aerosol distribution in China”. Insert a suitable reference at this point.
4. Why not used the observed PM₅ data during 2014-2017? Please check whether the number of stations is 1657.
5. Please identify the simulation period in this study.
6. It is recommended to list a table to introduce the experiments.
7. Precipitation can exert notable scavenging effects on PM₅ concentrations, whilst weak precipitation might increase PM_2.5 concentrations by hygroscopic increase associated with increased humidity. Therefore, it is recommended to examine the relative humidity anomalies in section 3.2, which might be able to explain opposite pattern of precipitation and wet deposition anomalies.
8. It is recommended to show probability density distributions of PM₁₀