Table 3.
Light measurement characteristics and devices
| Individual or environment | Light measurement technology | Light parameter measured | Study ID |
|---|---|---|---|
| Individual | HOBO Pendant Pendant temp/light Part # UA-002–64 | Intensity only | Dharani et al. 2012 [21], Wu et al. 2018 [17], Li et al. 2022 [22] |
| Actiwatch 2 | Intensity only | Read et al. 2014 [23], Read et al. 2015 [24], Landis et al. 2018 [25] | |
| Actiwatch Spectrum (model not specified, Pro or Plus in photo) | Intensity only | Gordon-Shaag et al. 2021 [26] | |
| Actiwatch Spectrum Plus | Intensity only | Mirhajianmoghadam et al. 2021 [27], Shneor et al. 2023 [28] | |
| Actiwatch Spectrum Plus | Intensity and spectral composition | Ostrin et al. 2018 [29] | |
| Clouclip | Intensity only | Wen et al. 2020 [30] | |
| Clouclip | Intensity and duration | Li et al. 2020 [31], Zhang et al. 2023 [32] | |
| FitSight wrist-worn watch (patent WO2015152818A1) | Intensity only | Li et al. 2021 [33] | |
| Akeso sensor | Intensity only | Fan et al. 2022 [34] | |
| Smart watch ‘Mumu’ equipped with a light sensor, accelerometer and GPS receiver | Illuminance, UV irradiance | He et al. 2022 [16], Chen et al. 2024 [35] | |
| Eye-wear transmittance measured with UV-2600 spectrophotometer | Spectral composition only | Torii et al. 2017 [18] | |
| MyLyt Tracker | Intensity and duration | Dakhal et al. 2024 [36] | |
| Environment | Luxmeter Lutron LX-101A, Lutron Electronics Co Inc | [Horizontal illuminance inferred] in lux in the centre of the nursery room in April 2017 between 10 am and 12 noon | Cohen et al. 2022 [37] |
| HOBO Pendant Pendant temp/light Part # UA-002–64 [not worn; used for classroom daylight factor assessment] | Intensity only | Suh et al. 2022 [38] | |
| Lux meter TES 1330 | Average illuminance (intensity) and illuminance uniformity (minimum to average ratio) for desks and blackboards from evening measurements of electric light | Hua et al. 2015 [39] | |
| spectral measurement instrument (Model OSP-350S, Hangzhou Ouhong INTELLIGENT Technology Co. Ltd, http://www.ohomesmart.com/) | Intensity, spectral composition | Cai et al. 2024 [40] | |
| Meteorological data | local daylight hours using astronomical table (include intensity, timing, duration, solar elevation; hours of darkness), regardless of actual exposure | Cui et al. 2013 [41] | |
| annual sunshine duration | city-level 10-year climatic data | Leng et al. 2021 [19] | |
| meteorological data; for analysis: season only taken into account (summer, winter) | local daylight hours | Hecova et al. 2023 [42] | |
| China Meteorological Data Sharing Service (http://Data.cma.cn/) data from 2018–2020 | average monthly sunshine duration for 103 areas, defined as duration of direct sunlight from sunrise to sunset (> 120 W/m2), unaffected by shading (clouds, fog), measured in hours | Ma et al. 2024 [20] | |
| NASA/NOAA’s Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) low-light imaging data | Artificial Light at Night: Radiance, nW/cm2/sr (at satellite) which is proportional to reflected irradiance (at surface level) | Liu et al. 2024 [43] |
Where studies include terms “lux”, “(light) intensity” and “(light) exposure” to refer to illuminance, the approach here is to use the same term in quotations. Some devices reporting illuminance measurements at the level of the child may not be generally accurate, e.g. due to instrument limitations spectral, directional or dynamic sensitivity characteristics, even for a calibrated device [44]