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1. The impact of color correlated temperature and illuminance levels of office lighting on stress and cognitive restoration

   https://doi.org/10.1016/j.jenvp.2025.102628  

   Awada, Mohamad; Gerber, Burcin Becerik; Lucas, Gale M; Roll, Shawn C (June 2025, Journal of Environmental Psychology)

   In modern workplaces, the well-being and productivity of employees are increasingly recognized as essential for organizational success. This study explores the impact of lighting interventions—specifically, Correlated Color Temperature (CCT) and illumination intensity—on stress and cognitive function restoration among office workers. A between-subjects experimental design involving 100 participants assessed the effects of various lighting conditions on stress responses and cognitive performance after exposure to stress-inducing and cognitive fatigue tasks. Five experimental conditions were studied: 100 lux & 7000 K, 100 lux & 3000 K, 1000 lux & 7000 K, 1000 lux & 3000 K, and a baseline condition of 500 lux at 3700 K. Results indicated that lighting conditions significantly influence both physiological stress markers (such as skin conductance level and heart rate) and cognitive performance. Specifically, warm, and dimmed lighting (3000 K, 100 lux) effectively reduced stress markers and perceived stress levels, aligning with theories suggesting the calming effects of warmer white light tones. Conversely, cooler lighting (7000 K) was associated with enhanced cognitive performance and reduced cognitive fatigue, potentially due to its similarity to natural daylight, stimulating an alert state conducive to mental tasks. These findings suggest that lighting interventions offer a non-intrusive strategy to improve well-being and productivity in office environments, particularly addressing acute symptoms. 

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2. Advancing Human-Centric LED Lighting Using Na₂MgPO₄F:Eu²⁺

   https://doi.org/10.1021/acsami.1c00909  

   Hariyani, Shruti; Brgoch, Jakoah (March 2021, ACS Applied Materials & Interfaces)

   null (Ed.)

   The proliferation of energy-efficient light-emitting diode (LED) lighting has resulted in continued exposure to blue light, which has been linked to cataract formation, circadian disruption, and mood disorders. Blue light can be readily minimized in pursuit of “human-centric” lighting using a violet LED chip (λem ≈ 405 nm) downconverted by red, green, and blue-emitting phosphors. However, few phosphors efficiently convert violet light to blue light. This work reports a new phosphor that meets this demand. Na2MgPO4F:Eu2+ can be excited by a violet LED yielding an efficient, bright blue emission. The material also shows zero thermal quenching and has outstanding chromatic stability. The chemical robustness of the phosphor was also confirmed through prolonged exposure to water and high temperatures. A prototype device using a 405 nm LED, Na2MgPO4F:Eu2+, and a green and red-emitting phosphor produces a warm white light with a higher color rendering index than a commercially purchased LED light bulb while significantly reducing the blue component. These results demonstrate the capability of Na2MgPO4F:Eu2+ as a next-generation phosphor capable of advancing human-centric lighting. 

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3. Exploring the Limitations of Environment Lighting on Optical See-Through Head-Mounted Displays

   https://doi.org/10.1145/3385959.3418445  

   Erickson, Austin; Kim, Kangsoo; Bruder, Gerd; Welch, Gregory F. (October 2020, ACM Symposium on Spatial User Interaction)

   null (Ed.)

   Due to the additive light model employed by most optical see-through head-mounted displays (OST-HMDs), they provide the best augmented reality (AR) views in dark environments, where the added AR light does not have to compete against existing real-world lighting. AR imagery displayed on such devices loses a significant amount of contrast in well-lit environments such as outdoors in direct sunlight. To compensate for this, OST-HMDs often use a tinted visor to reduce the amount of environment light that reaches the user’s eyes, which in turn results in a loss of contrast in the user’s physical environment. While these effects are well known and grounded in existing literature, formal measurements of the illuminance and contrast of modern OST-HMDs are currently missing. In this paper, we provide illuminance measurements for both the Microsoft HoloLens 1 and its successor the HoloLens 2 under varying environment lighting conditions ranging from 0 to 20,000 lux. We evaluate how environment lighting impacts the user by calculating contrast ratios between rendered black (transparent) and white imagery displayed under these conditions, and evaluate how the intensity of environment lighting is impacted by donning and using the HMD. Our results indicate the further need for refinement in the design of future OST-HMDs to optimize contrast in environments with illuminance values greater than or equal to those found in indoor working environments. 

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4. A dataset from a coordinated multi-site laboratory study investigating the Hue-Heat-Hypothesis

   https://doi.org/10.1038/s41597-025-05962-1  

   Bavaresco, Mateus; Cureau, Roberta Jacoby; Pigliautile, Ilaria; Barna, Edit; Deme_Belafi, Zsofia; Belussi, Lorenzo; Chinazzo, Giorgia; Chiucchiù, Agnese; Danza, Ludovico; Deng, Zhipeng; et al (December 2025, Scientific Data)

   Abstract Understanding cross-modal environmental perception is essential for improving occupant well-being and human-centric building design. This paper presents an open-access, multi-site database developed under the IEA-EBC Annex 79 project to test the Hue-Heat Hypothesis (HHH), which hypothesizes that light hue may influence thermal perceptions. The database comprises 543 experimental rounds conducted in eight laboratories across six countries and diverse climate zones, following a shared, rigorously designed protocol. During summer and winter campaigns, participants were exposed to controlled thermal environments and counterbalanced lighting conditions (neutral, reddish, bluish). The database includes detailed metadata on environmental variables, physiological measurements (i.e., heart rate and skin temperature), and self-reported perceptual responses. It also provides standardized technical documentation for each test room, including the detailed experimental protocol and translated survey instruments. All materials are available on the Open Science Framework under the “Multi-site Hue-Heat-Hypothesis Testing” repository. This resource supports research into multi-domain human comfort, enabling analysis of cross-modal and combined effects on human perception and physiological reactions. 

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5. Cognitive performance, creativity and stress levels of neurotypical young adults under different white noise levels

   https://doi.org/10.1038/s41598-022-18862-w  

   Awada, Mohamad; Becerik-Gerber, Burcin; Lucas, Gale; Roll, Shawn (December 2022, Scientific Reports)

   Abstract Noise is often considered a distractor; however recent studies suggest that sub-attentive individuals or individuals diagnosed with attention deficit hyperactivity disorder can benefit from white noise to enhance their cognitive performance. Research regarding the effect of white noise on neurotypical adults presents mixed results, thus the implications of white noise on the neurotypical population remain unclear. Thus, this study investigates the effect of 2 white noise conditions, white noise level at 45 dB and white noise level at 65 dB, on the cognitive performance, creativity, and stress levels of neurotypical young adults in a private office space. These conditions are compared to a baseline condition where participants are exposed to the office ambient noise. Our findings showed that the white noise level at 45 dB resulted in better cognitive performance in terms of sustained attention, accuracy, and speed of performance as well as enhanced creativity and lower stress levels. On the other hand, the 65 dB white noise condition led to improved working memory but higher stress levels, which leads to the conclusion that different tasks might require different noise levels for optimal performance. These results lay the foundation for the integration of white noise into office workspaces as a tool to enhance office workers’ performance. 

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