BIOLOGICAL AND PHYSICAL DOSIMETERS FOR MONITORING SOLAR UV-B LIGHT

A biological dosimetry system for measuring solar UV-B light was established using bacteriophage T1 with E. coli Bs-i as the host cell. Also a new physical UV-B dosimeter was developed which can specifically detect the UV spectral region related to inactivation of phage Tl. Phage Tl is very stable in liquid suspension and it has adequate sensitivity to measure the intensity of solar UV-B. In addition, the survival of phage Tl responded linearly to UV fluences when plotted semi-logarithmic ally. Thus Tl seemed to have characteristic features making it suitable material as a biological dosimeter for sunlight. Outdoor experiments throughout one year showed that the mean amount of solar UV light in summer was about 6 fold larger than that in winter at Isehara (139.5°E, 35.5°N), Japan. A novel physical dosimeter which responds faithfully to UV-B light under atmospheric conditions on the ground was developed as well. The spectral response was very close to that of biological materials. Readings of this UV-B dosimeter could be converted into the efficiency of sunlight upon biological materials. This instrument is compact; it can also be used as an erythemal dosimeter. © 1990, Journal of Radiation Research Editorial Committee. All rights reserved.