## Materials and Methods
### Methods
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Specimens** & \begin{tabular}{c} **Porous** \\ **Material Type** \\ \end{tabular} & \begin{tabular}{c} **Dilution** \\ **Solution Type** \\ \end{tabular} & \begin{tabular}{c} **Epoxy** \\ **Contents (\%)** \\ \end{tabular} & \
\begin{tabular}{c} **Number of** \\ **Washings** \\ \end{tabular} &
\begin{tabular}{c} **Freezing–Thaw** \\ **Cycles** \\ \end{tabular} \\ \hline Z-D-C & & & & & 0 & 0 \\ (Control) & & & & & 1 & 0 \\ Z-D-0-1 & & & & & 0 & 0 \\ Z-D-1-1 & & & 1 & 1 & 0 \\ Z-D-1.5-0 & Zeolite & Deionized & & & 0 & 0 \\ Z-D-1.5-1 & & water & 1.5 & & 1 & 0 \\ Z-D-2-0 & & & & & 0 & 0 \\ Z-D-2-1 & & & & 1 & 0 \\ Z-D-2-10 & & & & & 10 & 1 \\ Z-I-C (Control) & & & & & 0 & 0 \\ Z-A-0-1 & & & & & 1 & 0 \\ Z-A-1-0 & & & & & 0 & 0 \\ Z-A-1-1 & & Zeolite & & alcohol & 1 & 1 & 0 \\ Z-A-2-0 & & & & & 0 & 0 \\ Z-A-2-1 & & & & & 1 & 0 \\ Z-DA-1-0 & & 90\% deionized & & & 0 & 0 \\ Z-DA-1-1 & & water and 10\% & & & 1 & 0 \\ Z-DA-2-0 & & isopropyl & & & 0 & 0 \\ Z-DA-2-1 & & alcohol & & & 1 & 0 \\ C-D-C & & & & & 0 & 0 \\ (Control) & Coconut shell & Deionized & & & 1 & 0 \\ C-D-2-1 & activated & water & & & 10 & 0 \\ C-D-2-10 & carbon & & & & 10 & 1 \\ \hline \hline \end{tabular} Note: the specimen notation includes five parts except for control specimens, which are Z-D-C, Z-I-C, and C-D-C; the first and second parts indicate the types of porous material and dilution solution for coating on the textile fabrics, the third part represents the ratio of the epoxy resin content in the dilution solution, and the fourth and fifth parts represent the number of washing and freeze–thaw cycles, respectively.  
\end{table} 
Table 3: Main parameters for evaluating the NO\({}_{\text{x}}\) and SO\({}_{\text{x}}\) removal rates of the textile fabric specimens. The fine dust particles on the textile fibers were measured using a machine that counted the number of fine dust particles with a laser [20]. As shown in Figure 4a, the counting machine comprised a laser counter, a chamber, and a fan. The octagonal chamber had a dimension of 405 mm \(\times\) 405 mm \(\times\) 120 mm. The dimension of the textile fabrics specimen was 115 mm \(\times\) 115 mm \(\times\) 10 mm. The fabrics were attached onto plywood, which is not considerably affected by the static electricity, to fix it in the chamber (Figure 4b). To circulate the fine dust particles in the chamber, the fan was operated with a constant wind velocity of approximately 9.78 m/s during the experiment. The variation of the number of fine dust particles with respect to time was measured by counting the fine dust particles reflected by the laser. The fine dust particles used was A1 ultrafine test dust (ISO 12103-1, Arizona Test Dust), which is commonly used for the testing air purification filters [21]. The sizes of most of the A1 dust particles ranged between 0.97 and 5.5 \(\upmu\)m, which is similar to that of the ultrafine dust particles (2.5 PM) in the air [21]. Most of the A1 dust was circulated continuously by the airflow generated from the fan, whereas only some dust was attached to the chamber. Since the number of fine dust particles decreased even without the textile fibers in the chamber, the number of fine dust particles obtained from the chamber containing the textile fabric specimen was compared with that without the textile fabric specimen. Figure 3: Washing and freeze–thaw process of the textile fabrics with porous materials. Figure 2: Coating method of the textile fabrics. **(a)** Producing dilution solution for coating. **(b)** Coating and drying. Figure 5 shows the measurement machine for the removal of SO\({}_{\rm x}\) and NO\({}_{\rm x}\) by the textile fabrics coated with the porous materials. The measurement machine was composed of a chamber, a velocity and flow controller, a gas inlet and outlet, and a gas analyzer. The chamber had shape of a rugby ball with a 90 mm inner diameter and 178 mm length. The textile fabric specimen was placed on the circular platform in the center of the chamber.