Wavelength-specific urban nighttime light modulates expressed sentiment across China

Zhang, C, Meng, M, Chen, Z, Du, W ORCID: https://orcid.org/0000-0002-5115-7214, Dong, W, Wang, J, Gao, B, Yi, F, Zhu, K, Hu, J, Fu, Y, Yang, J, Li, M and Wang, Q, 2026. Wavelength-specific urban nighttime light modulates expressed sentiment across China. Nature Cities. ISSN 2731-9997

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Abstract

As cities brighten under rapidly expanding lighting infrastructure, residents face increasing sentimental risks at night. While artificial light at night (ALAN) is linked to mental health risks, its wavelength-specific effects remain poorly understood. Here we integrate satellite observations of ALAN and sentiment analysis of geotagged social media posts to quantify wavelength-specific associations between urban light exposure and expressed sentiment across China. We find that exposure to blue light (424–526 nm) increases negative sentiment by 15.9%, while moderate green light (506–612 nm) enhances positive sentiment by 5.0%. Spatial mapping further reveals pronounced disparities both within and between cities, with elevated sentiment risk concentrated in commercial areas and eastern cities of China. Notably, optimizing correlated color temperature reduces sentiment risk by 89.7% compared to intensity reduction alone. These findings provide evidence-based guidance for urban lighting design to promote public mental well-being through spectral optimization, not just brightness control.

Item Type:	Journal article
Publication Title:	Nature Cities
Creators:	Zhang, C., Meng, M., Chen, Z., Du, W., Dong, W., Wang, J., Gao, B., Yi, F., Zhu, K., Hu, J., Fu, Y., Yang, J., Li, M. and Wang, Q.
Publisher:	Nature Publishing Group
Date:	2 February 2026
ISSN:	2731-9997
Identifiers:	Number Type 10.1038/s44284-025-00384-x DOI 2568317 Other
Rights:	This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use (https://www.springernature.com/gp/open-research/policies/accepted-manuscript-terms), but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: http://dx.doi.org/10.1038/s44284-025-00384-x
Divisions:	Schools > School of Social Sciences
Record created by:	Laura Borcherds
Date Added:	06 Feb 2026 11:44
Last Modified:	06 Feb 2026 11:44
URI:	https://irep.ntu.ac.uk/id/eprint/55198

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