eprintid: 10204586 rev_number: 13 eprint_status: archive userid: 699 dir: disk0/10/20/45/86 datestamp: 2025-03-13 12:36:02 lastmod: 2025-03-13 12:36:02 status_changed: 2025-03-13 12:36:02 type: thesis metadata_visibility: show sword_depositor: 699 creators_name: Zhao, Chengpeng title: The effects of spectral power distribution with high melanopic efficiency on visual and atmosphere perceptions of offices ispublished: unpub divisions: UCL divisions: B04 divisions: C04 divisions: F34 note: Copyright © The Author 2025. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. abstract: Recent investigations into the effects of spectral power distributions (SPD) have largely kept separate the impact on the human’s circadian system from impressions of interior lighting. When daylight is insufficient, blue-enriched electric light sources are considered as an alternative to deliver a stronger stimulus to circadian system of occupants in offices. However, such light sources may not always be desired. At present, it is still not clear how to balance the non-visual effects of light on circadian rhythm and user satisfaction of office lighting. Therefore, this research aims to explore the influences of SPD with high Melanopic Daylight Efficacy Ratio (M-DER) on visual and atmosphere perceptions in the context of Integrative Lighting design for offices. Three objectives were proposed to achieve this aim. The first objective seeks to test can cold white light sources be more acceptable if they have SPDs closer to the daylight. The second objective is to examine if increasing melanopic efficiency by shifting peak wavelength of blue primary affects visual and atmosphere perceptions. The third objective is to explore how Duv affects atmosphere perceptions of office lit by SPDs with melanopsin stimulating peak wavelengths. Three psychological experiments were conducted with a multi-channel LED lamp which can closely resemble the SPD of daylight. The results suggest neither using SPD of daylight nor changing Duv improve user satisfaction of electric lighting. Metameric approaches can increase melanopic efficiency of SPD without significantly affecting visual and atmosphere perception, but the colour matching functions should be selected with care. There was evidence suggesting melanopsin may play a role in colour vision. It is anticipated that these results will assist lighting designers and manufacturers in selecting the most beneficial light spectra for the health and well-being. date: 2025-02-28 date_type: published oa_status: green full_text_type: other thesis_class: doctoral_open thesis_award: Ph.D language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 2359947 lyricists_name: Zhao, Chengpeng lyricists_id: CZHAO97 actors_name: Zhao, Chengpeng actors_id: CZHAO97 actors_role: owner full_text_status: public pages: 242 institution: UCL (University College London) department: Bartlett School Env, Energy and Resources thesis_type: Doctoral citation: Zhao, Chengpeng; (2025) The effects of spectral power distribution with high melanopic efficiency on visual and atmosphere perceptions of offices. Doctoral thesis (Ph.D), UCL (University College London). Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10204586/2/Thesis%20-%20Chengpeng%20Zhao.pdf