Simulation of Threshold UV Exposure Time for Vitamin D Synthesis in South Korea

Abstract

The threshold exposure time for synthesis of vitamin D was simulated by using a radiative transfer model considering variations in total ozone, cloud, and surface conditions. The prediction of total ozone took the form of an empirical linear regression with the variables of meteorological parameters in the upper troposphere and lower stratosphere and the climatology value of total ozone. Additionally, to consider cloud extinction after the estimation of clear-sky UV radiation using a radiative transfer model simulation, a cloud modification factor was applied. The UV irradiance was estimated at one-hour intervals, and then, to improve the temporal resolution of the exposure time simulation, it was interpolated to a one-minute resolution. Exposure times from the simulation clearly followed seasonal and diurnal cycles. However, upon comparison with observations, biases with large variations were found, and the discrepancy in the exposure time between the observations and simulations was higher in low UV irradiance conditions. The large deviations in the prediction errors for total ozone and the simplified assumption for the cloud modification factor contributed to the large deviations in exposure time differences between the model estimation and observations. To improve the accuracy of the simulated exposure time, improved predictions of total ozone with a more detailed cloud treatment will be essential.

Measurement and Assessment of Occupational Exposure to Solar Ultraviolet Radiation in Makurdi Metropolis, Benue State, Central Nigeria

“…# = 0.9697 (4) = 4509.5 ! " # = 0.9024 (5) respectively to make the dosimeter effectively estimate cumulative UV radiation exposures in J/m 2 . The slope of the calibration equation gives the calibration constant while" # shows the goodness of the calibration fit.…”

“…P3-6510) was used for measuring UV exposures. The UV meter detects both UV-A and UV-B and then calculates the UV index and UV irradiance (solar power density in W/m 2 ) through averaging the readings of the various wavelengths according to the Erythemal Action Spectrum [5].…”

“…Where E is the exposure in (J/m 2 ), I is the measured irradiance (W/m 2 ) and ∆t is the exposure time interval from t 1 to t 2 [5].…”

“…The dark pigmentation in the native Africans shields against the effects of UV in damaging the skin surface, while per-mitting sufficient UV penetration to the epidermis to produce sufficient amounts of vitamin D [3]. Solar UV radiation is responsible for the production and synthesis of vitamin D but over-exposure to it causes sunburn, skin cancer, skin deformation, eye problems (such as cataracts, pterygium), and immune depression [3][4][5]. Human exposure to solar ultraviolet radiation has important public health implications.…”

Niveles de 25(OH)D durante la pandemia de COVID-19: impacto del confinamiento y la radiación ultravioleta

“…[5][6][7] La ponderación biológica de los espectros solares de radiación UV con el espectro de acción anterior a la vitamina D se ha utilizado para predecir la capacidad de sintetizar vitamina D con variaciones por la latitud, estación y hora del día. También se ha utilizado para evaluar el efecto de las nubes en la producción de vitamina D. Por esto último, se aplica un factor de modificación de las nubes a los resultados de la radiación UV para calcular el espectro de acción para la biosíntesis de vitamina D. 8,9 Finalmente, la temperatura ambiente también sería un factor contribuyente al mantenimiento de niveles adecuados de vitamina D. 10 En 2019, en la ciudad de Wuhan, China, surgió un nuevo coronavirus designado como SARS-CoV-2, el cual provocó un brote inusual de neumonía viral. Al ser altamente transmisible, esta nueva enfermedad por coronavirus, también conocida como enfermedad por coronavirus 2019 (COVID-19), se ha propagado rápidamente por todo el mundo.…”