Pupils' use of school outdoor play settings across seasons and its relation to sun exposure and physical activity.

Background: Long outdoor stay may cause hazardous exposure to ultraviolet radiation (UVR) from the sun even at high latitudes as in Sweden (Spring to Autumn). On the other hand, long outdoor stay is a strong predictor of primary school children´s free mobility involving moderate to vigorous physical activity (MVPA). UV-protective outdoor environments enable long outdoor stay.

Solar Ultraviolet Radiation Exposure Proxy-estimated by Sky View Fish-eye Photography-Potentials and Limitations from an Exploratory Correlation Study.

Potentials and limitations of sky view fish-eye photography and calculation of the percentage of free sky (sky view factor, SVF) as a proxy to estimate solar ultraviolet radiation (UVR) exposure in shade settings are investigated using controlled situations. SVF and measured solar UVR exposure correlated at high mid-latitude (56.65°N) near autumnal equinox in September.

Suberythemal Sun Exposures at Swedish Schools Depend on Sky Views of the Outdoor Environments - Possible Implications for Pupils' Health.

More scheduled outdoor stay is increasingly advocated for school children. This study measured 2(nd) , 5(th) and 8(th) graders' erythemal UV-exposure in September, March and May at four Swedish schools. We related those exposures, as fractions of total available ambient radiation, to the schools outdoor environments differing in amount of shade, vegetation, and peripheral city-scape quantified as percentage of free sky view calculated from fish-eye photographs.

Vitamin D levels after UVB radiation: effects by UVA additions in a randomized controlled trial.

Background: Ultraviolet B (UVB) radiation increases the serum level of 25-hydroxyvitamin D [25(OH)D]. However, the impact of UVA on vitamin D synthesis by UVB is poorly understood clinically.

Objective: To examine how different combinations of UVA and UVB radiation affect S-25(OH)D for the same vitamin D-weighted exposure.