Development of a technique for spectral solar ultraviolet albedo measurements of building materials

Abstract

For the solar elevation angles of 33 to 39 degrees in this research, the erythemal UV measured in the direction of the wall material was of the order of 0.4 MED/h where an MED is defined as a minimum erythemal dose. The UV albedo calculated as the ratio of the irradiance in the direction of the wall and the solar irradiance on a horizontal plane for human erythema was 0.27, 0.24, 0.22 and 0.19 for the MDF, black plastic, grey colourbond and green colourbond respectively. In comparison, employing the photoconjunctivitis action spectrum, the albedo was 0.23, 0.21, 0.20 and 0.15 for the MDF, black plastic, grey colourbond and green colourbond respectively. The measured UV albedo may be due to the UV albedo from the material and the diffuse component of the UV solar radiation. This is shown by the albedo of 0.15 and 0.20 for the UVA (320 to 400 nm) and UVB (280 to 320 nm) respectively for the green colourbond. At the shorter wavelengths, there is a greater fraction of diffuse radiation.