## 5 Conclusions  
In this work, the dynamic response and separation effect of multi-factor separation of atmospheric particulate matter based on the composite electric field are investigated. A dynamic model for the separation of atmospheric particulate matter considering the effect of a composite electric field was established. In the dynamic model, the changes of the electric field force, basket force, additional mass force, and air resistance are taken into consideration. Through the numerical solution of the model, the dynamic response of the separation of atmospheric particles based on the composite electric field is discussed. Through these responses, in order to separate particles more accurately, it is a feasible separation method to reduce the drag coefficient and control the electric field strength. Compared with other methods, the method proposed in this work is easy to operate and has little environmental requirements. The valuable phenomena obtained are as follows:  
1. In the acceleration room, the velocity of atmospheric particles increases with the increase in particle diameter, and increases with the increase in electric field strength. Particles can pass through the acceleration room faster. The displacement of the particles in the \(Y\)-axis direction is negligible and does not affect the subsequent separation movement.
2. In the separation room, when the composite electric field changes, the displacement of particles in the \(Y\)-axis direction gradually increases from a negative displacement to a positive displacement as the electric field strength increases, which provides the basics of the separation. When the drag coefficient changes, there will be a sudden increase in displacement.
3. When the drag coefficient and the combined electric field work together, as the particle diameter increases, the Y-direction displacement assumes a \"bow\" shape that twists from negative to positive displacement. As the drag coefficient decreases, the shape becomes more prominent. The electric field strength affects the separation direction of the particles.  
Conceptualization, M.W. and S.L.; Data curation Y.W. and H.Z.; Funding acquisition, J.Z.; Methodology, M.W.; Project administration, S.L.; Software, M.W.; Validation, S.L.; Writing--original draft, M.W.; Writing--review & editing, Y.W., H.Z. and S.L. All authors have read and agreed to the published version of the manuscript.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \(\mathbf{PM_{100-10}}\) & \(\mathbf{PM_{10}}\) & \(\mathbf{PM_{2.5}}\) & \(\mathbf{PM_{1}}\) & \(\mathbf{PM_{10-2.5}}\) \\ \hline
8.02 \(\mathrm{\SIUnitSymbolMicro g/m^{3}}\) & 4.98 \(\mathrm{\SIUnitSymbolMicro g/m^{3}}\) & 4.83 \(\mathrm{\SIUnitSymbolMicro g/m^{3}}\) & 4.25 \(\mathrm{\SIUnitSymbolMicro g/m^{3}}\) & 0.15 \(\mathrm{\SIUnitSymbolMicro g/m^{3}}\) \\ \hline \hline \end{tabular}
\end{table}
Table 2: Atmospheric particulate matter concentration.  
Figure 17: Comparison of the particle size distribution of simulated atmospheric particulate matter with experiment result in ref. [18].  
**Funding:** This work was supported in part by the National Natural Science Foundation of China under Grant 11802168, Grant 61603238, and Grant 51575331, in part by project funded by China Postdoctoral Science Foundation (No. 2019M661458), and in part by Science and technology projects in Henan province of China.  
**Acknowledgments:** The authors would like to thank the anonymous reviewers for their constructive and helpful comments.  
**Conflicts of Interest:** The authors declare that there is no conflict of interest regarding the publication of this paper.