## 1 Introduction  
The metropolitan area of South Korea includes Seoul, Gyeonggi-do, and Incheon and accounts for 11.8% of the South Korean area. The population of the metropolitan area included over 26 million people in 2019, accounting for 50.03% of the total population. Seoul occupies a small area of 605 km\({}^{2}\) but has a population of 10 million people [1]. Seoul already has a saturated population, and economic losses due to traffic congestion continue to increase. In addition, demand for transportation is increasing due to the rapid construction of new cities around the metropolitan area. However, congestion costs are expected to increase, as traffic volume in some zones, especially during rush hour, exceeds the capacity due to the lack of transportation facilities. Also, the congested road zones in the metropolitan area are concentrated on the road connecting Seoul and Gyeonggi-do, which is 159.8 km long, as shown in Table 1. Accordingly, as of 2019, the average commuting time by public transportation in the Seoul metropolitan area was 81 min: 2.8 times higher than the OECD average of 29 min [2]. Therefore, to overcome this traffic issue, many companies are actively working on urban air mobility (UAM), i.e., air public transportation rather than ground. Although helicopters are commonly used in urban areas, helicopters are not suitable for UAM, such as air taxis, due to the noise, emissions, and high costs of operation. Thus, electric vertical take-off and landing (eVTOL) vehicles have emerged as an alternative. Many eVTOL vehicles are under development, such as Airbus Vahana, Cityairbus, Lilium Jet, Bell Nexus, Joby S4, Hyundai SA-1, etc., and Uber has announced Elevate, a project that will allow commuters to use flying cars by 2026 [3]. According to a UAM survey of major specific cities conducted by Booz Allen Hamilton, more than 50% of commuters responded positively to UAM boarding [4], and if UAM becomes commercialized, many commuters would use eVTOL when commuting. Therefore, the locations of the vertiports should be in a place that is conveniently accessible to commuters. UAM will minimize traffic congestion on ground roads, and it is believed that this change will be positive for most of the population. In addition, we must consider that this is a new transportation method that has never existed before, so infrastructure is needed to support it. In other words, eVTOL should be designed not only for take-off and landing but also for service infrastructure, such as vertiports, which allow passengers to stand by and board. The problem of emissions and noise should also be considered because the air transport is being operated in urban areas. Moreover, in the case of the Seoul metropolitan area in South Korea, where the area of land is limited, and the residential area is excessively concentrated, these issues are exacerbated. In addition, since the noise level is relative to people, it is important to first analyze it with indicators of standard noise intensity and later create a sustainable system under mutually beneficial conditions for all stakeholders. As UAM emerges as an alternative transportation in the near term, adverse energy and environmental impacts, particularly noise, may impact community acceptance and potentially persist as the market matures into larger-scale operations. Of the concerns raised, the potential for noise was one of the most commonly raised concerns. However, people were less concerned about individual aircraft noise and more concerned about total ambient noise from multiple aircraft operating in close proximity. People indicated a preference for limiting aircraft operations overnight, particularly in residential neighborhoods. The most common bothersome noises experienced by the respondents were noise from motor vehicles and neighboring properties, and they tended to be most bothered by noise at home. Overall, respondents preferred that UAM technology have no noticeable noise. The noise levels of the technology could affect support for UAM.