In this paper, the relation of cloudy skyluminance with particle scatter and air mass is discussed by using the results of atmospheric and geometrical optics.
The louvers may be adjusted so that they reject summer radiation, admit overcast skyluminance or act as light shelves, depending on the nature of day and the requirements of each storey.
This paper suggests a zenith luminance converting factor. By means of multiplying outdoor horizontal sky illuminance by this factor, the value of zenith luminance of the sky can be obtained.