[Solar time--the importance of standard time for the UV-exposure of the skin].
Dermatologists recommend that people avoid exposure to the blazing sun around noontime. In most places in Europe there are considerable deviations between true solar time and standard time: Firstly, during summer the standard time in the European countries is set one hour ahead according to the summer time or daylight saving time. Secondly, in all countries of Western and Central Europe, except Great Britain, Ireland and Portugal, standard time uniformly is Central European Summer Time (CEST). Although this standard central European time zone refers to the longitude 15 degrees East of Greenwich, it is valid for all longitudes up to nearly about 9 degrees West of Greenwich. This leads to a maximum deviation between standard time and solar time of nearly 1 hour and 36 min. Thirdly, a comparably small time shift is due to the equation of time. It amounts up to a maximum of about six and a half minutes at the end of July. Altogether, the shift between standard time and true solar time adds up to about 2 h 40 min at the Spanish coast of the Atlantic Ocean, e.g. noon is not at 12:00 but rather at 2:40 p. m. (14:40 h CEST).A paradoxical situation results for British holiday-makers who go to Spain. Although they move to a more westerly geographical position they do not put back their clocks but set them one hour ahead, since they enter the CEST zone. The recommendations given by dermatologists to the people regarding their exposure to the sun should allow for these geographical and astronomical facts.
Stick
Carsten
C
Institut für Medizinische Klimatologie der Universität Kiel, Germany. c.stick@med-klimatologie.uni-kiel.de
D004781:Environmental Exposure / Q000517:prevention & control*; D005060:Europe; D006801:Humans; D009381:Neoplasms, Radiation-Induced / Q000209:etiology / Q000517:prevention & control*; D011829:Radiation Dosage; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D012878:Skin Neoplasms / Q000209:etiology / Q000517:prevention & control*; D013471:Sunburn / Q000209:etiology / Q000517:prevention & control*; D013997:Time Factors; D014195:Travel; D014466:Ultraviolet Rays