## 3 Results and Discussion
### Field Survey Results and Analysis
#### 3.2.1 Physical test results and analysis
Figure 7 shows the performance of the physical environment of the tube entrance space approach to one end of a shopping mall. All of the environment's temperatures and most of the humidity index values for the three test points exceeded the comfort zone. The maximum value of tp3 was 32.3 \({}^{\circ}\)C, while the mean outdoor temperature was 29 \({}^{\circ}\)C. The average illuminance levels of the three test points in the tube entrance (connection to building) did not reach the national standard; tp3 and tp7 were especially low. Both of the test points located at the indoor and outdoor junctions had light  
Figure 6: diagram of the physical test results from the middle tubular space. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Site**} & **Test** & \multirow{2}{*}{\begin{tabular}{c} **Temperature** \\ **Point** \\ **Number** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Humidity** \\ **(\({}^{\circ}\)C)** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Illuminance** \\ **(\({}^{\circ}\)C)** \\ \end{tabular} } & \multicolumn{2}{c}{**Air**} & \multirow{2}{*}{**PM2.5**} & \multirow{2}{*}{**PM10**} & \multirow{2}{*}{**HCHO**} & \multirow{2}{*}{**CO\({}_{2}\)**} \\  & & & & & & & & & \\ \hline W1 & Tp1 & 32.1 & 47.7 & 990 & 0.196 & 47.9 & 67.2 & 0.022 & 681 \\ W2 & Tp4 & 28.1 & 70.2 & 72.0 & 0.265 & 45.4 & 64.3 & 0.030 & 1163 \\ W3 & Tp8 & 25.5 & 76.8 & 19.0 & 0.0 & 66.1 & 92.0 & 0.057 & 1000 \\ W4 & Tp11 & 28.3 & 57.4 & 153.6 & 0.307 & 52.0 & 73.1 & 0.044 & 892.1 \\ \hline \hline \end{tabular} Note: The data in the grey background indicate that it is beyond comfortable zone.  
\end{table} 
Table 5: Average values for the physical test results in the middle tubular space. levels that would require human eyes a significant amount of time to adjust to the darkness. This can cause sensations of insecurity and discomfort when entering from a strong outdoor light environment. The concentration of CO\({}_{2}\) in these spaces was also high, with maximum values for tp3 and tp7 reaching 1761 ppm and 1690 ppm, respectively. To sum up, because most of the tube entrance space was connected to a shopping mall and was close to the outdoors, the thermal environment and humidity levels were low, light problems were obvious, and concentrations of CO\({}_{2}\) were high. According to Figure 8, the thermal and humidity environments at the tube entrance space near the subway were obvious. The temperatures at the four test points all exceeded the comfort level. The average temperature at tp5, with an elevation depth of 14.4 m, was 2.5 \({}^{\circ}\)C lower than that of tp10 and tp13, which were at an elevation depth of 9.2 m. The higher wind speed relieved the high humidity and CO\({}_{2}\) concentrations at the tube entrance space (connection to subway). Generally, the average humidity was lower than 70% and both the average and maximum values of CO\({}_{2}\) were greatly reduced. However, due to the influence of the subway piston wind, the wind speed presented a sinusoidal fluctuation and the direction of the wind speed changed periodically. Thus, the wind environment became the most unfavorable factor with regards to comfort. To sum up, ventilation was one of the most detrimental comfort factors at the tube entrance space (connection to subway). It was affected by the piston wind so that cold air (from the air conditioning) was sometimes sucked out of the subway platform layer and hot air was pumped out of the tubular space. People who stayed at that location for long periods of time were frequently affected by two