Public Health Messages Associated with Low UV Index Values Need Reconsideration.

Overexposure to ultraviolet (UV) radiation is the main modifiable risk factor for skin cancer. The Global Solar Ultraviolet Index (UVI) was introduced as a tool to visualize the intensity of UV radiation on a certain day, which should enable and encourage people to take appropriate protective measures. The 'low' exposure category of the UVI, defined by a rounded UVI value of 0, 1 or 2, was linked to the health message 'No protection required' by the World Health Organization and partner organizations.

Erythemal UV Radiation on Days with Low UV Index Values-an Analysis of Data from the German Solar UV Monitoring Network over a Ten-year Period.

According to the World Health Organization and partner organizations, no protection against ultraviolet (UV) radiation is required on days with "low" values (i.e., values <3) of the Global Solar Ultraviolet Index (UVI).

Implications of Low Levels of the UV Index for Sun Protection.

A Global Solar Ultraviolet Index (UVI) value of 2 is generally linked to the health message 'You can safely stay outside!' To examine whether this is sound advice for all skin types and even for prolonged periods spent outside we used erythemal irradiance data of all 136 days during the study period from 2014 till 2016 with such a UVI measured by the German Federal Office for Radiation Protection (BfS) in Munich, Germany. A comparison between the ambient erythemal doses calculated for various time intervals and minimal erythemal doses (MEDs) of the Caucasian skin types I-IV led us to a critical reappraisal of the above health message. Specifically, the message might be misleading if people with a fair complexion want to spend several hours outside, because without any protective measures the doses received can be sufficient to induce erythema.

UV Index monitoring in Europe.

The UV Index was established more than 20 years ago as a tool for sun protection and health care. Shortly after its introduction, UV Index monitoring started in several countries either by newly acquired instruments or by converting measurements from existing instruments into the UV Index. The number of stations and networks has increased over the years.

Spectral and Spatial UV Sky Radiance Measurements at a Seaside Resort Under Clear Sky and Slightly Overcast Conditions.

Spatial measurements of the diffusely scattered sky radiance at a seaside resort under clear sky and slightly overcast conditions have been used to calculate the sky radiance distribution across the upper hemisphere. The measurements were done in the summer season when solar UV radiation is highest. The selected wavelengths were 307, 350 and 550 nm representing the UVB, UVA and VIS band.