Figure 1. Cooling centers in senior center and government buliding

Seoul, the capital city of Korea, operates cooling centers to protect residents from extreme summer temperatures. These shelters provide air-conditioned spaces where vulnerable populations, especially the elderly, can rest safely during heatwave periods. The city designates public facilities, such as community centers, senior centers, and libraries, as official cooling shelters each summer.

We aimed to conduct a spatial assessment to identify areas that may be underserved or lacking in cooling centers.

Figure 2. Variables related to cooling centers

Fig 2 shows variables that we used to identify heat-risk areas: (a) the annual average number of heatwave days, (b) tropical nights, and  (c) the average daily maximum temperature, as well as (d) the number of Basic Livelihood Security recipients and (e) the senior daytime population.

Figure 3. Heat-risk index

All variables were aggregated to 50 × 50 m grid cells and standardized using min–max normalization (Fig 3a). A heat-risk index was then computed by multiplying the standardized variables, and the top 20% of grid cells with the highest index values were classified as high heat-risk areas (Fig 3b). We used these top 20% areas as the basis for evaluating the suitability of cooling center locations.

• Results: areas in need of cooling centers 

Seoul, Korea, is a highly walk-friendly city. Most people rely on public transportation and walk as part of their daily routines. However, in midsummer, temperatures often rise to around 30 °C (86 °F) or even higher, and the average relative humidity stays around 70–80%. Citizens are exposed to intense heat, which makes walking difficult. To address this problem, local administrative offices provide shade canopies around crosswalks, so pedestrians can avoid direct sunlight (Fig 6). Seodaemun-gu is a densely populated and vibrant district in Seoul, filled with active shopping streets, trendy cafés, and plenty of places to explore on foot.

We wanted to (1) assess whether the shade canopies are installed in appropriate locations and (2) identify where additional shade canopies are needed.

Using DEM data, a hillshade analysis was conducted to identify the areas of shade that would have formed between 1:30 PM and 3:30 PM on August 1, 2018, historically the hottest day at 39.6°C (≈103.3°F). The analysis used a solar azimuth of 213.49° to 254.46° and a solar elevation of 67.47° to 47.84°. Higher cell values (shown in red) indicate areas that receive more sunlight (Fig 7).

Figure 8 presents the results of the shade canopy location assessment. In the map, red indicates the locations of existing shade canopies, while blue represents the proposed locations.

Near Sinchon Nonghyup Bank is a good example of shade canopies. There are no tall buildings to the southwest of the crosswalk, causing strong sunlight to fall on the area in the afternoon. As a result, the current installation is appropriately placed (Fig. 8a). In contrast, near Hongeun Bridge, the construction site barriers block the sunlight, creating shade on the opposite side of the crosswalk. Therefore, relocating the shade canopy to that shaded side appears to be a better option (Fig. 8b). Lastly, the Sinchon Rotary is one of the most crowded areas in Seodaemun-gu and is surrounded by many tall buildings, yet the crosswalk remains unshaded during the afternoon. Thus, it is recommended as a location for installing a shade canopy (Fig. 8c).