Optical and chemical properties of atmospheric organic aerosols

In the light of recent field and laboratory measurements we developed a str uctural and chemical model for organic atmospheric aerosols. The model orga nic aerosol consists of an aqueous core surrounded by a hydrophobic organic layer of biological origin. The role of organic aerosols is to concentrate organic materials at the surface and transport these organic molecules in the atmosphere. The nascent hydrophobic organic aerosol is not expected to nucleate clouds efficiently. Processing by atmospheric radicals creates hyd rophilic sites on the surface. The processed, aged organic aerosol is expec ted to accommodate water and form cloud condensation nuclei. Processing of organic atmospheric aerosols implicates them in atmospheric radiative trans fer. (C) 2000 Elsevier Science Ltd. All rights reserved.