Walking has a positive impact on people’s emotional health. However, in the case of serious air pollution, it is controversial whether walking exercise can still improve individuals’ emotional health. Using data from the 2014 wave of the China Labor-Force Dynamics Survey, this study explored the relationship between walking and emotional health with different levels of environmental pollution. The results indicated that respondents who took regular walks had better emotional health than those who did not walk regularly. For those whose main mode of physical exercise was walking, the average number of walks per week was significantly and positively correlated with their emotional health; however, the average duration of the walk had no significant impact on their emotional health. Moreover, for those whose main mode of physical exercise was walking and who lived in neighborhoods with a polluted environment, regular walking still had a positive impact on their emotional health. This suggests that even if environmental pollution is serious, walking still plays an important role in regulating individuals’ mental health. We propose that in order to promote the emotional health of residents, it is necessary to create more public spaces for outdoor activities and simultaneously increase efforts to control environmental pollution.

The built environment is among the critical factors in older adults’ travel behavior, and a favorable built environment can encourage them to travel and engage in various activities. Existing studies have mostly focused on exploring the correlation between the built environment and travel behavior, ignoring the heterogeneity between the two at different times of the day. In this study, we conducted structured, face-to-face interviews in the Nanjing (China) metropolitan area to investigate the time consumed per trip by older adults using various travel modes and used the structural equation and random forest models to explore the relationship between the built environment and older adults’ travel time. The results demonstrated that older adults had different perspectives on travel during different time periods. Different environments and the convenience of destinations affected their overall satisfaction during travel. We found a nonlinear relationship between the built environment and travel time. Metropolitan street connectivity initially had a positive effect on travel time until a certain threshold or peak, whereafter a gradual decline ensued. This nonlinear relationship also existed between the proportion of green space and the distance to subway stations. These results can guide the retrofitting and construction of age-friendly metropolitan infrastructure facilities that promote older adults’ mobility.

Integrated energy supply service stations (IES) are a new type of transportation energy infrastructure offering the advantages of comprehensive functions and intensive land use while providing more convenient and efficient energy supply services. Through the analysis of service station characteristics, this study regards the IES as a spatially superimposed combination of various energy supply services, proposes a layout method from the perspective of combination optimization, and establishes a station optimization model for energy supply stations. This method aims to further coordinate and optimize the combination of various energy supply stations to achieve global optimization of the energy supply service system. Finally, this study uses a hypothetical situation for example analysis to verify the validity and rationality of the method. The layout plan proposed in this study has important theoretical and practical significance for how to achieve the optimal layout of an IES.