Effects of tree plantings and aspect ratios on pedestrian visual and thermal comfort using scaled outdoor experiments

The effects of brightness and prominent colors on outdoor thermal perception in Chongqing, China

Outdoor thermal comfort has become an important factor affecting human mental and physical health due to rapid urbanization. This study aimed to investigate the influence of brightness and prominent colors on thermal perception in hot summer and cold winter regions. Meteorological measurements were conducted accompanied by subjective thermal and visual questionnaires (n = 2020) during summer and winter. The physiological equivalent temperature (PET) was applied as thermal indices to evaluate the influence of visual conditions on thermal perception. The results showed that (1) the neutral PET is 20.2 °C with a range of 14.8 ~ 25.7 °C in Chongqing and neutral illumination range is 0 ~ 8663 lx. (2) Thermal sensitivity is most great in neutral brightness than bright and too bright groups. The influence of outdoor prominent colors in winter supports hue-heat hypothesis. However, in summer, result only supports the hypothesis under low thermal stress. Both cool and warm colors can reduce the thermal sensitivity of visitors compared to neutral colors (gray and white). (3) The interactions between colors and brightness are more obvious under low thermal stress levels. (4) Thermal perceptions of females are more greatly affected by brightness and prominent colors compared with males. These results could help landscape designers better understand the correlation between the thermal and visual environments and provide a reference for comprehensive designs of urban open spaces.

The impact of tree species and planting location on outdoor thermal comfort of a semi-outdoor space

Previous studies have shown that tree arrangement provides effective regulation of the outdoor thermal environment and combats the urban heat island (UHI) effect. To further explore semi-outdoor thermal environment improvement using tree arrangement, we selected two common arbor species from Guangdong Province, namely, Lagerstroemia speciosa and Bombax ceiba. We discuss the influence of courtyard tree arrangements on the thermal environment of semi-outdoor spaces (courtyards and overhead spaces) of a teaching building in a hot-humid area. The ENVI-met model was used and verified with field measurements; the universal thermal climate index (UTCI) was used as an index to evaluate the thermal environment of semi-outdoor spaces. We found that (1) adjusting the distance between trees and buildings reduced the UTCI values by 0.4 (overhead spaces) and 0.8 ℃ (courtyards); and (2) when the distance between the arbor and the building is fixed, the UTCI values of arranging Lagerstroemia speciosa can be reduced by up to 0.5 (overhead spaces) and 1.0 ℃ (courtyards) compared to that of Bombax ceiba; this study provides practical suggestions for the layout of trees in semi-outdoor spaces of teaching buildings in the hot-humid areas of China.

Evaluating the Annual Effect of the Sky View Factor on the Indoor Thermal Environment of Residential Buildings by Envi-met

The effect of the sky view factor (SVF) on outdoor thermal comfort has been extensively explored, while its impact on the indoor thermal environment is ignored. This research combined Envi-met and kriging models to explore the annual effect of the sky view factor on the indoor thermal environment. Different from previous studies, this study explored the effect of the sky view factor on indoor temperature rather than outdoor temperature, and from the perspective of a full year instead of a typical summer day. The analytical results reveal that an increase in the sky view factor raised the indoor air temperature every month. Although a low sky view factor was beneficial to the insulation of the built environment at night, it was proven that in Chenzhou city, the indoor air temperature was still higher in a built area with a high sky view factor than with a low sky view factor. In addition, the sky view factor was shown to have a nonlinear relationship with indoor thermal comfort throughout the year. When the sky view factor increased from 0.05 to 0.45, the indoor temperature increased by around 10 °C at 16:00 and increased by about 4 °C throughout the night for each month, and from the view of the annual cycle, the cooling demand duration increased by 1611.6 h (18.4%), and the heating demand duration decreased by 1192.3 h (13.61%).

The mental health of children and young people living in big cities in a revolving postpandemic world

PURPOSE OF REVIEW

The world's population is increasingly urban, with most children and young people growing up and living in cities. Evidence suggests that urbanicity is linked to an increased risk for the development of mental health disorders. Rather than an accumulation of risk factors, urbanization is a complex process that profoundly structures living conditions. In this sense, it is timely to discuss what are the social and structural determinants of mental health of children and young people in such settings.

RECENT FINDINGS

Three domains of determinants of mental health were selected for discussion: economics and living conditions, crime and violence, and urban layouts. For each, we debated realities faced by urban children and young people, providing an overview of recent evidence on implications for mental disorders and well being. We also discuss the potential impacts of the covid-19 pandemic on each domain, as well as recommendations for future action.

SUMMARY

Structural factors are of major relevance for the mental health of children and young people living in cities. The agenda of mental health promotion and prevention must include whole-of-society interventions aimed at improving living conditions, including economic and social capital, violence prevention and urbanistic planning.