Solar ultraviolet radiation on the ground level of Isfahan

ABSTRACT

Ultraviolet [UV] radiation affects human organs such as skin, eyes and immune system, as well as animals and plants. The main natural source of UV radiation is the Sun. To study the effects of solar UV radiation there is a need to quantify variations of solar energy received on the earth surface at different intervals. To measure UV radiation a broadband fiber optic UV spectrometer was used. With the spectrometer, the energy received at earth surface was measured from wavelength 100 to 400 nm [the UV spectrum]. Measurement duration was from January first to the end of December 2003, and from sunrise to sunset. The received UVC at the ground level was too low to be measured. The measured UVA was between 11 to 21 times higher than UVB energy during the measurement period. The minimum UV received on the ground level was in January and it was 14.5x10[5] J/m[2] while the maximum was in July and it was 80.14x10[5] J/m[2]. Total UV radiation received on the ground level was during the year of measurement period 579 x10[5] J/m[2]. The measurement showed that UVC intensity on the earth surface was negligible. As the wavelength increased the receiving UV energy at the ground level also increased. From the results, it has become clear that the main health consequences of solar UV were related to UVA band. As the intensity of the UVR during summer is too high, a method of UV health risk reduction should be devised