Model for the Global Irradiance of the Solar Biologically‐effective Ultraviolet‐radiation on Inclined Surfaces

Abstract

The body surface area of man is the relevant receiving surface for solar UV radiation. To consider this body surface geometry, the biologically-effective UV radiation of the solar global radiation was measured. This was done at 26 differently aligned measuring points whose orientation was determined by the angle of inclination (vertical) and the azimuth (horizontal). Approximately eight hundred sets of measurement series were carried out at 33 different sites. A simple model, developed from the data obtained, made it possible to calculate relative irradiance as a function of the angle of inclination and the ground reflection (UV albedo). Thus relative risk of solar UV exposure to different regions of the body can be assessed. In addition to this, if the irradiance on a horizontal plane (measured or calculated by a corresponding model) is taken into consideration, the absolute values for UV irradiance on tilted planes can be determined.

Horizontal and sun-normal spectral biologically effective ultraviolet irradiances

“…Other research has measured the erythemal UV with polysulphone dosimeters on inclined surfaces and on the human face [12,13]. Schauberger [14] has modelled the biologically effective UV on inclined surfaces. However, none of this previous research has measured the UV spectrum with a spectroradiometer on a sun normal and horizontal surface to provide information on the comparison of the UV spectrum and biologically effective UV for the two orientations.…”

Personal UV exposure in high albedo alpine sites

“…The quantification of UV exposure of human skin indeed requires measurements of erythemal doses (Parisi, 2005) on tilted surfaces. Only a few systematic UV measurements for differently oriented surfaces are available (Schauberger, 1990;Webb et al, 1999). Oppenrieder et al (2003) developed and built a new automatic system to measure radiation fluxes in 27 positions at three different altitude sites in Germany in order to have quantitative UV data related to the directions of the oriented surfaces of human body in different environment conditions.…”

Modelling ultraviolet exposures in a school environment

“…46,47,48 These risks are related to vitamin D deficiencies caused by limitations in diet, and the sunlight induced epidermal reaction of 7-dehydrocholesterol into pre-vitamin D 3 . 49 At the latitude examined here, the biological response of vitamin D 3 production in human skin exceeds the predicted erythemally effective UV.…”

“…Often however, the influence of the surrounding environment is neglected, due to the time required, and difficulties in making accurate environmental measurements sufficient to detail all the factors that impact ambient UV. The influence of solar position and its effect on surface albedo 2,3 , variation with sky view 4 , and surface inclination 5,6 have each been investigated and modelled in past research, however no mechanism has yet been developed to take each of these factors into account to model horizontal plane damaging UV in a realistic environment. Additionally, horizontal plane damaging UV does not accurately represent exposure likely to be incident on exposed surfaces of the human body although many studies have been and continue to be conducted to investigate and model this effect.…”