## Materials and Methods
### Methods  
Tables 2 and 3 summarize the main parameters studied in the experiments. The adsorption of fine dust particles by static electricity was investigated in the uncoated textile fabrics. The length and number of layers of uncoated textile fabrics were selected as the main parameters. The length of the uncoated textile fabrics was set as 3.5, 7, or 12 mm, which correspond to the densities of 0.08 g/cm\({}^{2}\), 0.13 g/cm\({}^{2}\), and 0.22 g/cm\({}^{2}\), respectively. The number of layers was set as 4 or 8. Static electricity was introduced into all the textile fabrics artificially by rubbing their top surfaces. In the textile fabrics coated with zeolite, the epoxy content and dilution solution were selected as the main parameters. Additionally, the numbers of washings and freeze-thaw cycles were selected as the main parameters to consider the effects of rain and temperature in the external environment. Deionized water and isopropyl alcohol were used for the dilution solution. Based on the previous test results performed by [PERSON] et al. [17], resins and crosslinkers were incorporated at a mass ratio of 4:1 and then used as an adhesive to enhance the effectiveness of the cross-linking. The ratio of the epoxy content in the diluted solution was varied from 0 to 2%. The number of washings was set to 0, 1, or 10, and the number of freeze-thaw cycles to 0 and 1 cycle. The number of washings and freeze-thaw cycles used for the textile fabrics coated with coconut shell activated carbon were identical to those selected for textile fabrics coated with zeolite. The optimum epoxy content and solution determined from the coating process of zeolite were used for the coating the textile fibers with coconut shell activated carbon. Figure 1: Internal microstructure and pore distribution of each material used. (**a**) Textile fabrics. (**b**) Zeolite. (**c**) Coconut shell activated carbon. \begin{table}
\begin{tabular}{c c c c c} \hline
**Specimen** & **Length (mm)** & **Layers** & **Density (g/cm\({}^{2}\))** & **Details** \\ \hline C (Control) & - & - & - & \\
3.5–4 & 3.5 & 4 & 0.08 & \\
3.5–8 & 3.5 & 8 & 0.08 & \\
7.0–4 & 7 & 4 & 0.13 & \\
7.0–8 & 7 & 8 & 0.13 & \\
12–4 & 12 & 4 & 0.22 & \\
12–8 & 12 & 8 & 0.22 & \\ \hline \end{tabular} Note: the specimen notation includes two parts except for specimen C. The first and second parts indicate the length and number of layers of uncoated textile fabrics, respectively.  
\end{table} 
Table 2: Main parameters for evaluating the fine dust particle removal rate of the textile fabric specimens. Figure 2 shows the coating method of zeolite or coconut shell activated carbon and the epoxy on the textile fibers. The considerably high viscosity of epoxy results in a high possibility of forming entangled lumps with the zeolite or coconut shell activated carbon powder [18]. Hence, to reduce the formation of entangled lumps, the epoxy needs to be diluted to a high-flow solution [19]. As shown in Figure 2, the deionized water or isopropyl alcohol for dilution was mixed with the epoxy resin for 3 min. Subsequently, the zeolite or coconut shell activated carbon powder was added and mixed for 5 min. The epoxy hardener was finally added and mixed for 2 min. The textile fibers were fully dipped into the combined dilution solution and stirred continuously. The dipping time was 30 min. The dipped textile fibers were dried under a shade at 20 \(\pm\) 2 \({}^{\circ}\)C and 60% \(\pm\) 2% humidity. Figure 3 shows the washing and freeze-thawing process of the textile fibers coated with porous materials. In the washing process, the textile fibers coated with porous materials were washed by running water with the water drop velocity of 3 m/s, which is the maximum water velocity in rain. In the freeze thawing process, the textile fibers were placed in a chamber with a temperature below \(-\)14 \({}^{\circ}\)C for 24 h after washing, and then thawed under the shade at 20 \(\pm\) 2 \({}^{\circ}\)C and 60% \(\pm\) 2% humidity. Before testing, the processed textile fibers were dried under the shade.