The aim of this study is to suggest planning strategies for managing comfortable thermal environments in urban areas by local cold air generated in mountains, which finally contributes to making sustainable and eco-friendly cities. For this purpose, we selected urban areas in the Honam Jeongmaek in Korea and analyzed the nighttime cold airflow and altitude of the cold air layer generated in mountains, by using the KALM (Kaltluftabflussmodell) model which calculates the amount of cold air generated during the nighttime without winds. The results of analysis found that the local airflows generated in Mt. Chuwol, Mt. Mudeung, Mt. Cheonun, Mt. Byeongpung and Mt. Geum influenced the entire study site from across Gwangju Metropolitan City to adjacent areas. Therefore, the mountains generated major cold airflows should be designated as the management area for securing cooling function. As a result of detailed analysis, most developed areas, such as Buk-gu, Seo-gu and Nam-gu, as well as industrial areas, did not have a smooth flow, so management strategies were needed. In particular, Mt. Mudeung and Mt. Cheonun were the source areas of the local cold air generation and the generated flows from the mountains could influence into developed areas of Gwangju Metropolitan City. Thus, thorough preservation policies are required for Mt. Mudeung and Mt. Cheonun from development that causes damages to mountainous terrain and topography. This study could support the establishment of systematic management plans of the Honam Jeongmaek in preparation for climate change. In addition, it is expected to be used to develop policies related to the quantitative expansion of mountain areas with cooling functions and the conservation of sustainable mountain areas.

Under the growing threat of urban heat stress, street canyons play a critical role in shaping the pedestrian thermal environment. While street greenery is an effective mitigation strategy, its performance varies substantially with physical characteristics—such as aspect ratio, street width, and sidewalk width—highlighting the need for spatially adaptive design. This study evaluates the effects of sidewalk width, street orientation, and planting structure on thermal conditions in a humid subtropical climate in Daegu Metropolitan City, Republic of Korea. The analysis focuses on open low-aspect-ratio street canyons (H/W = 0.86 for E–W and 0.43 for N–S orientations). Using a validated ENVI-met (Version 5.6.1) model based on field measurements from Daegu, Republic of Korea, 56 street-greening scenarios were simulated by systematically varying sidewalk width, street orientation, planting rows, spacing, and planting structure. Results show that multi-row planting served as the primary structural framework governing thermal performance. Optimal configurations varied with sidewalk width, with two-row planting for 6 m sidewalks and three-row planting for 10 m sidewalks providing the most effective cooling. The greatest cooling (−2.02 °C) was achieved when optimized multi-row configurations were combined with multi-layer planting. Once optimal multi-row configurations were established, the presence of understory vegetation had a greater influence on thermal improvement than its specific composition, allowing flexibility in understory design. Clear spatial asymmetries were identified, with the highest thermal stress occurring on the north-side sidewalk in E–W streets and the west-side sidewalk in N–S streets. Targeted planting in these locations produced greater cooling benefits than uniform strategies. These findings provide a spatially grounded framework for climate-responsive street greenery and offer practical design guidance, highlighting the need for context-specific, optimized multi-row planting strategies adapted to local urban and climatic conditions.

Rapid urbanization and increasing particulate matter (PM) pollution have heightened public health risks in high-density urban environments, highlighting the need for effective nature-based solutions. Although urban green infrastructure (UGI) is widely recognized for its potential to improve air quality, existing classification systems, particularly those based on development purposes, remain inadequate for capturing the functional mechanisms necessary for effective PM mitigation. This limitation hinders the development of context-sensitive planning strategies that account for spatial conditions, emission sources, and human exposure. To address this gap, this study develops a PM-oriented functional planning framework for high-density cities by reclassifying UGI according to PM mitigation functions rather than conventional purpose-based categories. Drawing on 8 Korean institutional/policy documents and a systematic review of 139 academic studies (124 international and 15 Korean), four functional classification criteria, namely development purpose, proximity to emission sources, receptor vulnerability, and physical structure, were identified and used to establish an evidence-informed typology comprising ten PM-oriented UGI types. These types were contextualized and operationalized within the Korean urban system as a representative model for complex, high-density urban development. The findings indicate that type-specific strategies emphasizing deposition, blocking, and dispersion are essential for effective PM mitigation. Structurally diverse vegetation can enhance particle deposition in residential areas, whereas optimized vegetation porosity improves performance in roadside environments. The proposed framework offers a decision-support tool for policymakers and urban planners; however, further empirical validation is required to assess its effectiveness and applicability across diverse urban contexts.

Climate change has intensified urban heat wave issues, particularly in Daegu, South Korea, which experiences the highest number of heat wave days nationally over the past 10 years. This study developed the app “The Warm” utilizing the Living LAB methodology to collect field information at the citizen level.The app, "The Warm," collects personal information such as gender and age of participants, as well as real-time personal thermal sensation information (on a four-point scale) from participants in the field. Based on the collected individual-level information, a personal thermal sensation prediction map is generated and provided.The Living LAB was conducted over two years in 2021 and 2022. In 2021, 31 citizens participated in testing and improving the app “The Warm” and establishing operational guidelines for the Living LAB. In 2022, 152 citizens were involved in comprehensive data collection. For the Living LAB, researchers, citizens, and public-private partnership organizations in Daegu collaborated. The Living LAB process included meetings for citizen training, activity monitoring, and result sharing. Citizens using the app “The Warm” collected 4,285 personal thermal sensation data points across Daegu for two years.Using the personal thermal sensation data collected through the app "The Warm," a heat prediction map for Daegu was developed. The prediction map was developed by analyzing the relationship between personal thermal sensation data and air temperature, green coverage ratio, road coverage ratio, sky view factor, and mean building height.The results of this study can contribute to collecting high-resolution, accurate field data at the citizen level. Furthermore, an analysis of the relationship between thermal comfort and urban factors was conducted in this study. This study serves as foundational research for future studies into the effectiveness of thermal adaptation strategies, such as providing urban shading network, in areas with thermal discomfort.