Lighting quality evaluation in underground public spaces — An integrated field and simulation study

A well-designed lighting environment is essential for creating comfortable and occupant-friendly underground public spaces. Previous studies have primarily focused on the impact of artificial lighting on occupant comfort in underground spaces, often relying on horizontal two-dimensional illuminance metrics for evaluation.

This study conducted an empirical investigation of the lighting environment in an underground public space in Suzhou, China. Ten measurement points were selected based on daylighting conditions, and subjective evaluation data were collected from 70 participants. A simulation model was calibrated and validated based on field measurements, enabling the analysis of a series of luminance metrics that characterize the lighting environment in three dimensions.

The results indicate that lighting distribution is a key factor influencing the comfort of underground lighting environments. Compared to skylights, sunken courtyards are more effective in enhancing visual comfort. Additionally, the luminance metrics of the 40° horizontal band demonstrate a certain advantage in predicting the lighting quality of underground public spaces. This study is expected to provide valuable data to support the optimization of underground public space design in the future.