Modeling the aerosol effects on the light field below a tubular-pipe: A case of clear sky conditions

• Aerosols are recognized as having unknown influence on the light pipe efficiency.
• Diffuse component of luminous intensity solid (LIS) for straight pipe was analyzed.
• Asymmetry parameter plays a crucial role in forming LIS under high aerosol loading.
• Aerosol microphysics is a good platform for optimum designing the light guides.

The question we have postulated is well founded since the air pollution is now recognized as one of the most actual problems of human life in many regions, especially in highly industrialized and densely polluted urbanized areas. Aerosols scatter the light depending on their sizes, shapes, and compositions, so the scattering pattern of a particulate matter appears fairly greatest modulator of the ground reaching diffuse light. Undoubtedly the aerosol optics represents an essential portion of information in modeling the illuminance in the interior spaces. However, the effects of both the diffuse light and the direct sunbeams are difficult to separate experimentally. We analyze the optical behavior of diffuse light field numerically using theoretical models of (a) light scattering in the atmospheric environment (based on mSOS – modified Successive Orders of Scattering) and (b) light propagation through the cylindrical pipe (HOLIGILM). The form of aerosol scattering function is controlled by asymmetry parameter (ASY) which is recognized to be one of the most important factors influencing the luminous intensity solid (LIS) – i.e., the angular distribution of luminous energy at the light tube base. Along with solar zenith angle and aerosol optical depth (AOD), the ASY plays a crucial role in transforming the daylight to the illuminance patterns on a horizontal plane situated below the light guide. The bulk single scattering albedo of aerosol particles – i.e., the overall scattering efficiency of aerosols, has only less impact on LIS.