## 3 Noise Analysis
### Noise Analysis
#### 3.5.2 Predicting the Effect of Measured Noise on Population  
To determine the number of people affected by noise, population data distributed in each hexagon were obtained. The population data were assumed by the number of people living in each administrative district minus the number of people moving to another administrative district for commuting at working time. Table 9 represents the distribution of the number of residents in each hexagon based on population data provided by the Ministry of the Interior and Safety and Statistics Korea.  
Figure 15 shows the overlapped image of the noise map obtained through AEDT and the administrative districts in the Seoul metropolitan area composed of hexagons. Table 10 represents the number of hexagons through which receptors pass each administrative district from the results in Figure 15. The results above 65 dB are the same for both paths since both occur on vertical take-off and landing. In other words, the effect of noise depends on the cruise section in which 60 dB receptors are distributed. Therefore, from the results in Table 10, the population residing in the 60 dB to 65 dB range was multiplied by the  
Figure 14: Noise maps for two different scenarios.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Region** & **Total Population** & \begin{tabular}{c} **Moving** \\ **Population** \\ \end{tabular} & \
\begin{tabular}{c} **Living Population** \\ \end{tabular} &
\begin{tabular}{c} **Population on** \\ **Each Cell** \\ \end{tabular} \\ \hline Gangeo-gu & 572,377 & 182,963 & 389,414 & 7489 \\ \hline Yangcheon-gu & 449,208 & 161,693 & 287,512 & 13,069 \\ \hline Yeongdeungpo-gu & 373,285 & 118,455 & 254,830 & 8220 \\ \hline Dongiak-gu & 384,076 & 145,204 & 238,872 & 11,944 \\ \hline Gwanak-gu & 485,826 & 182,685 & 303,141 & 7977 \\ \hline Seecho-gu & 415,629 & 135,668 & 279,961 & 4745 \\ \hline Gangnam-gu & 526,046 & 148,672 & 377,374 & 7702 \\ \hline Songpa-gu & 656,548 & 195,736 & 460,812 & 10,717 \\ \hline Mapo-gu & 363,789 & 123,102 & 240,687 & 8023 \\ \hline Yongsan-gu & 220,239 & 68,852 & 151,387 & 5407 \\ \hline Seongnam-si & 927,886 & 236,255 & 691,661 & 3908 \\ \hline Gwacheon-si & 66,420 & 24,530 & 41,890 & 931 \\ \hline \hline \end{tabular}
\end{table}
Table 9: Residents in each hexagon of metro county.  
noise-exposure ratio in the Miedema curve [22], and the number of people affected by high levels of noise in each scenario is shown in Table 11.  
As a result, the number of people affected by noise decreased by about 76.9% in a noise priority scenario compared to in a business priority scenario.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Region**} & \multicolumn{2}{c}{**Business Priority**} & \multicolumn{2}{c}{**Noise Priority**} \\  & **60 dB** & **65 dB** & **Above70 dB** & **60 dB** & **65 dB** & **Above 70 dB** \\ \hline Gangseq-gu & 11 & 3 & 1 & 5 & 3 & 1 \\ \hline Yangcheon-gu & 2 & - & - & - & - \\ \hline Yeongdeungpo-gu & 3 & - & - & - & - \\ \hline Dongjak-gu & - & - & - & - & - \\ \hline Gwanak-gu & - & - & - & - & - \\ \hline Seecho-gu & - & - & 1 & - & - \\ \hline Gangnam-gu & 6 & 4 & 1 & 2 & 4 & 1 \\ \hline Songpa-gu & - & - & - & - & - \\ \hline Mapo-gu & 2 & - & - & - & - \\ \hline Yongsan-gu & 10 & - & - & - & - \\ \hline Seongnam-si & - & - & - & - & - \\ \hline Gwacheon-si & - & - & - & - & - \\ \hline \hline \end{tabular}
\end{table}
Table 10: The number of hexagons per administrative district passing the noise area for two scenarios.  
Figure 15: Noise analysis results for two different scenarios in the modeled area.