Background: Ultraviolet (UV) radiation is divided
into three regions: UVA, UVB, and UVC. Both the quality
and quantity of solar UV radiation vary with various
factors including the elevation of the sun above the
horizon, as well as absorption and scattering of UV
photons by molecules in the atmosphere, notably
ozone and clouds. It is clear that whereas a moderate
amount of UV exposure is beneficial, too much is
detrimental, so there is a need to quantify variations
of solar UV on the earth surface, at different time
intervals. Materials and Methods: The measurement
of solar UV radiation in Yazd city was achieved by two
radiometers: 1) a special UVA light meter with
maximum sensitivity to 365nm in the range of 320-
390nm and 2) a radiometer with a probe for 280-320
nm in UVB radiation. Measurement duration was from
1st January to the end of December 2008 and from
sunrise to sunset, every one hour. Results: Daily
integral UVA radiation in December with the lowest
(0.38×105Jm-2) and July with the highest intensity
(5.26×105Jm-2) were found. The minimum and
maximum monthly UVA radiation on the ground level
of Yazd city were 25.8×105Jm-2 in December
and 128.7×105Jm-2 in July, respectively.
Conclusion: Based on UVB /UVA ratio the UVB
intensity at 12 o'clock is 25 times lower than the UVA.
Therefore, the integrated hourly UVB in this time is
equal to 3.13 kjm-2 and almost the effective UVB is
1.56 kJm-2 so the minimum required exposure time of
UVB radiation for one SDD and MED by hands and
head are about 22 and 110 minutes respectively.
Iran. J. Radiat. Res., 2012 10(3‐4): 187‐191
Bouzarjomehri F, Tsapaki V. Measurement of solar ultraviolet radiation in Yazd, Iran. Int J Radiat Res 2012; 10 (3 and 4) :187-191 URL: http://ijrr.com/article-1-988-en.html