Atmospheric aerosol has a substantial influence on climate. One of the least studied aspects of aerosols is their vertical structure. For the purposes of this thesis, a measurement campaign was performed, during which vertical profiles of aerosol physical properties were studied using the method of ski lift measurements. Radiative forcing of urban aerosol in infrared was also studied, on the basis of a simple theoretical model. The first part of the thesis discusses theoretical issues concerning aerosols, including their influence on climate, as well as the formation mechanism and types of smog. Next, the methodology and the results of the measurement campaign are presented. The last chapter consists of a theoretical analysis of the radiative forcing of urban aerosol in infrared.