The main aim of this abstract is determine associations between intermodal fraction of atmospheric aerosol and two fundamental fractions - fine and coarse aerosol. The particle size of intermodal fraction (PM2,5-1) is located between fine (PM1) an coarse (PM10-2,5) particles.
These two fundamental and most studied particel sizes ovelap in the size interval of intermodal fraction and they have not only different size, behaviour, residence time in atmosphere and chemical composition but they have different sources. The associations between these fractions are identified outdoors, indoors and in urban and rural locations.