2017 Yes https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5536284/ Zhou, Zhongqiang Asia Exposure Study Teachers Students Elementary (K-5) Temperature The median (Inter Quartile Range) light intensity in the BC (2,540 [1,330–4,060] lux) was greater than the TC (477 [245–738] lux, P < 0.001), though less than outdoors (19,500 [8,960–36,000] lux, P < 0.001). A prominent spectral peak at 490–560 nm was present in the BC and outdoors, but less so in the TC. Teachers and children gave higher overall ratings to the BC than TC, and light intensity in the BC in summer and on sunny days (>5,000 lux) was at the upper limit of children’s comfort for reading. In summary, light intensity in the BC exceeds TC, and is at the practical upper limit for routine use. Children and teachers prefer the BC.