Effects of neighbourhood morphological characteristics on outdoor daylight and insights for sustainable urban design

Urban daylight significantly affects the physical and mental health of urban residents. Many previous studies focused on how outdoor daylight conditions affect indoor daylighting of buildings, whereas the design of outdoor daylighting conditions, which also exerted an equally significant part, was relatively overlooked. There are also few studies empirically explored the outdoor daylight in various forms of mature urban neighbourhoods. Through investigating the outdoor pedestrian daylight performances of 11 representative open urban neighbourhood units in inner-city Shenzhen, this study aims to identify the influence of urban design factors. Through field investigation, mapping and on-site measurement, this study explored and analysed the horizontal illuminance level and site illuminance uniformity of 84 outdoor spaces. As the results revealed, urban morphological characteristics significantly affected the daytime pedestrian illumination. Specifically, the high-density mid-rise urban villages and the urban park demonstrated the best daytime outdoor visual comfort conditions. The multivariate regression test demonstrated that sky view factor exerted the greatest influence on the daytime outdoor illumination, followed by the mean building height, ground surface albedo and vertical uniformity. Hence, urban morphological patterns have great potential in optimizing urban design for outdoor daylighting behaviours and energy use, which is of great reference value in setting specific standards to achieve the goals of the initiatives of Healthy Cities.

Automated summary

Urban daylight has a significant impact on the physical and mental health of urban residents. The study found that urban morphological characteristics, such as high-density mid-rise urban villages and urban parks, play a key role in providing the best outdoor visual comfort conditions. Sky view factor was identified as the most influential factor impacting daytime outdoor illumination.