As cities are extremely vulnerable to the impacts of climate change, they are fundamental in addressing these changes. However, streets, which are external spaces accessed by citizens in daily life, play an important role in improving the urban environment and public health. This study considered Busan in South Korea as a case study to investigate street canyons, including street canyon geometries and tree configurations, of old, present, and new city centers. The influence of morphological factors on the microclimate and outdoor thermal comfort was evaluated using the ENVI-met program for extremely hot weather. Changes in the street width, street orientation, and street canyon aspect ratio had a significantly higher impact on the microclimate and thermal comfort index (p < 0.01). These results indicated that the orientation of the main street should be consistent with the prevailing wind direction of Busan. Further, the shading of adjacent buildings improved the outdoor thermal comfort and reduced the significance of tree configuration in deeper street canyons. In addition, tree height had a more significant impact on street environment than other tree configuration factors, especially when the tree height increased from 9 m to 12 m. We recommended that the thermal comfort level can be improved by dynamically adjusting the relationship between the planting distance and tree height in streets having shallow street canyons.

Air pollution, such as particulate matter (PM), and extreme weather are causing increasingly complex problems and socioeconomic damage in urban environments year-round. This study predicts extreme weather and air pollution changes that occur in urban street canyons as the basic data necessary for research on energy conservation. Changes in PM and microclimate elements based on the change in floor area ratio are analyzed. In addition, the effects of microclimate elements on the distribution of PM factors are examined. Based on the change in floor area ratio, high-concentration PM was negatively correlated with PM_2.5, PM₁₀, O₃, NO₂, NO_x, T_a, T_mrt, and T_surface. Extreme heat was observed to be negatively correlated with T_mrt and T_surface, and extreme cold negatively correlated with PM_2.5, PM₁₀, NO₂, and NO_x. The higher the floor area ratio, the higher the wind speed (WS), indicating a positive correlation between the two factors. T_a, T_mrt, and T_surface were observed to be negatively correlated with PM_2.5, PM₁₀, NO₂, and NO_x. WS showed negative correlations with PM_2.5, PM₁₀, NO₂, and NO_x. The results of this study can be used as basic data for the derivation of evaluation indices and to determine prediction and response strategies with respect to a combination of extreme weather and air pollution to ensure a suitable and sustainable quality of life. This study helps predict energy loads according to urban street canyon structures and examines whether trees and green walls are effective in reducing extreme weather and air pollution and saving energy.

The purpose of this study is to identify the relationship between weather variables and buildings damaged in natural disasters. We used four datasets on building damage history and 33 weather datasets from 230 regions in South Korea in a decision tree analysis to evaluate the risk of building damage. We generated the decision tree model to determine the risk of rain, gale, and typhoon (excluding gale with less damage). Using the weight and limit values of the weather variables derived using the decision tree model, the risk of building damage was assessed for 230 regions in South Korea until 2100. The number of regions at risk of rain damage increased by more than 30% on average. Conversely, regions at risk of damage from snowfall decreased by more than 90%. The regions at risk of typhoons decreased by 57.5% on average, while those at high risk of the same increased by up to 62.5% under RCP 8.5. The results of this study are highly fluid since they are based on the uncertainty of future climate change. However, the study is meaningful because it suggests a new method for assessing disaster risk using weather indices.

Urbanization has intensified population concentration, and the quality of residential environments has deteriorated owing to the accelerated construction of high-rise and high-density buildings. In this study, a quantitative analysis is conducted regarding the natural lighting and outdoor thermal comfort of apartment complexes, and satisfactory improvement measures for both factors are investigated. Natural lighting and outside microclimate modeling simulations and statistical analyses are performed on 27 cases using the layout planning factors of an apartment complex. In addition, outdoor thermal comfort analysis is performed by applying heat island mitigation factors (greening and reflective asphalt pavement) to cases satisfying the condition of daylight factor (DF ≥ 75%). To improve natural lighting, the azimuth (correlation coefficient −0.812) should be considered, and to improve outdoor thermal comfort, the aspect ratio should be considered (−0.402). The results of applying heat island mitigation factors suggest that greening can improve outdoor thermal comfort to a greater extent than reflective asphalt pavement. The significance of this study is that the measures to improve residential comfort have been determined by considering the factors affecting the residential environment.

Economic growths lead to population increases in large cities. This has brought about the growing necessity for apartment housing which has resulted in higher density populations living in high-rise apartment complexes. Therefore, the urban microclimate is aggravated due to the increasing ratio of artificial coverage and substandard daylight availability. To achieve a comfortable living environment and improve urban microclimates, a process considering the daylight availability and the outdoor thermal environment is required when designing apartment housing complexes. This study selected a total of 27 valid cases using an orthogonal array, L₂₇(3¹³) design of experiments (DOE). As a result of significance probability obtained in DOE analysis, the design factors that have an effect on the outdoor thermal environment and daylight availability were found to be building coverage ratio, distance between buildings, and azimuth. The rankings of the effect of design factors were shown to be in the order of azimuth > building coverage ratio > distance between buildings > floor area ratio > width/depth ratio. The surface temperature of the whole building decreased by 0.3 °C and Mean Radiant Temperature (MRT) decreased by 1.1 °C as a result of applying the greenery coverage ratio to apartment complexes. Heat Island Potential (HIP) also showed a decrease of 5.4 °C (at noon).

Urbanization can increase artificial coverage rates and emissions by causing increases in traffic, which represents a serious health risk to pedestrians. To create pedestrian-friendly environments in urban canyons, this study examined their microclimates and air quality; methods to improve the pedestrian environment were also explored, based on the current street green space practices in Seoul, Korea. Under these current standards, the physiologically equivalent temperature (PET) of the pedestrian roads was predicted to decrease by 1.29–1.44 °C, but this was insufficient to adjust the thermal stress level. The air temperature of the pedestrian road declined slightly; fine dust concentrations increased, and ozone concentrations decreased. The effects of increasing the planting occupancy on the pedestrian environment were then simulated, which resulted in decreases in PET of 3.04–3.49 °C, depending on the floor area ratio, thereby effectively lowering the thermal stress stage. The particulate matter concentrations increased, however, and the air quality deteriorated. Therefore, street greenery planning alone cannot sufficiently improve both the microclimate and air quality of urban pedestrian roads. Thus, it is necessary to plan street greenery spaces in parallel with measures to improve air quality.