Assessing the influence of sky view factor and building shadow ratio on thermal comfort in different local climate zones: Evidence from Beijing, China

Rapid urbanization and climate change have intensified heat-related risks in densely populated megacities, where significant intro-urban variations in thermal environments exist. Although previous studies have explored urban thermal disparities based on the Local Climate Zone (LCZ), the influence of building parameters on thermal environments, particularly their impact on outdoor thermal comfort across different LCZ scenarios, remains insufficiently investigated. This study classified the LCZ across the area enclosed by Beijing's Fifth Ring Road and employed ENVI-met simulations for LCZ 1–9, aiming to analyze spatial disparities in air temperature and outdoor thermal comfort. The impact of key building-related parameters influencing thermal conditions were analyzed, and a generalized additive model was applied to quantify their nonlinear associations with the physiological equivalent temperature. Our findings reveal substantial variations in air temperature and thermal comfort across LCZs, with densely built mid- and high-rise areas (LCZ 1, LCZ 2) consistently exhibiting lower air temperatures. In contrast, open mid- and high-rise areas (LCZ 4, LCZ 5) remained the warmest. However, thermal comfort patterns differed: low-rise areas (LCZ 3, LCZ 6) experienced the highest thermal discomfort, whereas open mid- and high-rise areas maintained moderate comfort levels throughout the day. According to Spearman correlation analysis, air temperature showed the highest correlation coefficients with the sky view factor, roughness element height, and building structure index, indicating their dominant roles in shaping microclimatic conditions. At the same time, thermal comfort showed the highest associations with sky view factor, building shadow ratio, and building density. The findings emphasize the essential role of architectural characteristics in modulating intra-urban thermal environments, thereby informing climate-adaptive planning and design strategies to alleviate heat stress and promote outdoor thermal comfort in high-density urban settings.