In Northeast China, most classrooms in primary and secondary schools still use natural ventilation during cold days in winter. This study investigated the thermal comfort and the perceived air quality of children in primary schools in severe cold regions in China. Field measurements were conducted in four typical primary classrooms in two naturally ventilated teaching buildings in the winter of 2016 in the provincial city of Shenyang. Six field surveys were distributed to 141 primary students aged 8 to 11, and 835 valid questionnaires were collected. The results showed that the indoor temperature and the daily mean CO₂ concentrations of the primary school classrooms ranged from 17.06 to 24.29 °C and from 1701 to 3959 ppm, respectively. The thermal neutral temperature of the primary school students was 18.5 °C, and the 90% thermal comfort temperature ranged from 17.3 to 20.1 °C. Children were able to respond to changes in indoor air quality, but there was no significant correlation between the children’s perceptions of air quality and the carbon dioxide levels in the classroom. In general, children have a lower comfort temperature than adults. In addition, children are more sensitive to temperature changes during the heating season than adults. Due to differences in thermal sensation between children and adults, the current thermal comfort standard based on adult data is not applicable to primary school buildings and children. The air quality evaluation during heating season indicates that it is necessary to add indoor air environment monitoring instruments and purification equipment to the naturally ventilated classrooms. At present and in the future, more research based on children’s data is needed to solve the indoor air environment problems in primary school buildings.

Atmospheric particulate matter (PM) pollution has escalated into a critical threat to urban public health and safety. Among urban functional zones, commercial districts—characterized by high human exposure—are simultaneously hotspots of pollutant accumulation. Consequently, PM mitigation in these areas has become an urgent challenge for sustainable urbanization. This study used Computational Fluid Dynamics (CFD) to simulate the diffusion process and vertical concentration distribution of particulate matter in commercial districts. The results showed that the concentration of PM2.5 decreased with increasing height, with the highest concentration in the respiratory zone (1.5 m) and basic diffusion above 50 m; There are significant differences in the concentration changes of pollutants under different combinations of architectural spaces. By establishing a 20 m block wind corridor, changing the relationship between the building and the street enclosure, and adjusting the form of the building podium and overhead design with building height multiples (6–12 m), strategies can effectively alleviate the accumulation of particulate matter in commercial blocks. These findings provide quantitative evidence for evidence-based retrofitting strategies aimed at reducing PM2.5 exposure in high-density commercial areas.

Urban green-space carbon sinks can contribute to reducing urban carbon emissions and supporting carbon-neutrality goals. This study examined the associations between urban green-space landscape patterns and above-ground carbon storage (AGCS) in Shenyang. The spatial distribution of estimated AGCS was mapped using ArcGIS and remotely sensed imagery. Pearson correlation analysis, geographically weighted regression, and an exploratory data-binning approach were used to evaluate associations between landscape pattern metrics (LPMs) and AGCS and to identify their thresholds. At the study-area scale, AGCS exhibited strong positive correlations with class area (CA) and largest patch index, weak negative correlations with patch density and landscape division index, and a weak positive correlation with Connectivity Index (CONNECT). These relationships varied among the three ring zones. Spatially, CA was positively associated with AGCS throughout the study area, whereas positive local coefficients for CONNECT occurred in 51.8% of the study area. The low- and high-carbon-storage thresholds were 7.26 and 10.79 for CA and 8.33 and 12.08 for CONNECT, respectively. Higher CA and CONNECT values above their low-carbon-storage thresholds were associated with a lower probability of a low-carbon-storage zone. These findings provide context-specific evidence that may inform urban green-space planning in Shenyang and offer a methodological reference for comparable case studies.

With the acceleration of urbanization, wind environment problems in high-density blocks have become increasingly prominent. Most existing studies only focus on the identification of influencing factors, lacking a complete closed loop from “diagnosis” to “design verification”. This study takes 174 blocks along the Qingnian Street Metro Line in Shenyang as research objects, uses PHOENICS (2019) software, and clarifies the seasonal distribution characteristics of the wind environment in high-density blocks through field measurement and simulation verification. The XGBoost-Shap method is employed to identify key morphological factors and their nonlinear influence mechanisms. The K-means clustering method is adopted to construct the typology of calm wind zones, which are classified into three categories: Type A (narrow street canyon-comprehensive resistance type), Type B (high-density enclosed type), and Type C (high-rise obstruction type). Multi-scenario simulations are conducted for each type, and differentiated optimization schemes are designed accordingly. The results show that under specific CFD boundary conditions representing typical cold climate urban environments, eight indicators, including enclosure degree (ED), sky visibility (SVF), and windward area ratio (FAI), have significant seasonal sensitivity effects on wind environments. The effect of multi-strategy collaborative optimization is significantly superior to that of a single intervention. This study verifies the effectiveness of the typological approach in bridging wind environment mechanism identification and spatial optimization design. Thresholds for indicators such as enclosure degree (ED), sky visibility (SVF), and building density (BD) can be used as preliminary design-screening tools, providing a reference for ventilation improvement design ideas along high-density subway lines in actual urban construction.