Modeling of Solar UV Reaching Ground Level for the Purpose of Antipsoriatic Climatotherapy in Poland

The antipsoriatic effectiveness of artificial UV light ,emitted by fluorescent tubes, has been supported by many authors. Nowadays, the climate therapy is carried out rather sporadically; only at a very few southernmost holiday resorts (the Dead Sea, the Canary Islands) with intense solar radiation throughout almost the whole year. Statistical analysis of the daily course of exposures to TL-01 tube radiation for 93 psoriatic patients from the Medical University of Łódź during 20-day phototherapy shows that the dose of 1J/cm2 represents a unit of single exposure necessary for psoriasis healing. This value is converted to the antipsoriatic effective dose of 317.9 mJ/m2 using the TL-01 lamp irradiance spectrum and the antipsoriatic action spectrum. It is proposed that the daily exposure of 317.9 mJ/m2 serves as the standard antipsoriatic dose (SAPD) providing a link between the cabinet and the out-door exposures. This value could be used for planning heliotherapy at any site.

A model is proposed to calculate ambient antipsoriatic doses for 3 h exposures around the local noon (9-12 GMT) based on satellite (OMI) measurements of ozone and the radiative cloud fraction. The model constants are determined by a comparison with pertaining antipsoriatic doses measured by the Brewer spectrophotometer in central Poland. It is found that 3 h exposures to solar radiation in the period 15 May-15 September provides the mean (2005-2013) doses in the range 2.7 -3.1 SAPD over Poland. The most effective site for antipsoriatic heliotherapy is the south/east part of Poland (the Bieszczady Mountains). The regional differences in the antipsoriatic potential of solar radiation are quite small, i.e. 15% difference between the site with the highest and lowest doses. Thus, heliotherapy could be treated as an alternative to the cabinet phototherapy for almost 4 months.

To help a patient with planning next day sunbathing schedule we prepare a numerical prognostic model to inform of optimal starting time and necessary sunbathing duration at any site in Poland. The prognostic map is available at web page. The model uses the forecasted column amount of ozone (by GFS High Resolution model) and the cloud cover (by WRF model) to calculate duration of sunbathing to take 1 SAPD. The duration of sunbathing in the upright body position is provided for next day every full hour between 6 am and 3 pm. We hope that for some patients self-controlled sunbathing will be more effective than standard indoor therapy as the psychological stress usually involved with medical treatment will be not present during individual heliotherapy.