PhD. Topics

Influence of atmospheric aerosol on the intensity of diffuse daylight

Inorganic technologies and materials

RNDr. Ladislav Kómar, PhD.

Contact:

Faculty of Civil Engineering SUT in Bratislava

In addition to air molecules, small particles with dimensions of hundreds of micrometers to tens of micrometers, so-called atmospheric aerosol, exist in the Earth’s atmosphere. The origin of these particles can be natural (desert storms, fires, volcanic activity, etc.) or anthropogenic (mining, industrial and construction activities, exhaust fumes, etc.). Variability of aerosol particles cause changes in the intensity of daylight, which can manifest as a turbidity of the atmosphere. However, at elevated concentrations, e.g., in smog events in large cities, it can play an important role in reducing the availability of daylight for building interiors. While the scattering of radiation on air molecules we describe by so-called Rayleigh approximation, in the case of aerosols with sizes comparable to the wavelength of visible light, Mie theory is applicable. But this only applies to the simplest case of the spherical particles. However, the problem is much more complicated, as the atmospheric aerosol is generally of irregular shape, its size distribution and concentration, as well as its optical properties, can change over time and space. The basis of modeling the daylight availability is the radiation transfer equation, in which the properties of aerosols and their scattering phase function are usually unknown. From the measurements it is possible to determine the properties of particles and then model the intensity of diffuse light incident on the horizontal or vertical plane (windows of buildings). The aim of the work is to find the relationship between the properties of atmospheric aerosol and the amount of available daylight in interiors, as well as to model extreme atmospheric conditions (smog situations, desert storms, forest fires, volcanic eruptions, ...) and their impact on diffuse light variability.