Anthropogenic aerosols play a substantial role in the radiative properties of the atmosphere and EarthÕs climate and are thought to be significantly counteracting the radiative forcing of incremental greenhouse gases. Aerosol particles are strongly coupled with gas-phase chemistry and clouds, and these interactions may lead to possible changes in the oxidizing capacity of the atmosphere. One of the most important advances in aerosol research in the past decade has been the realization that it will not be possible to understand (and even less so to be able to predict) the chemical state of the atmosphere without taking into account its multi-component and multi-phase nature. Particle size is central to the description of the radiative effects of aerosols and of their influences on clouds. Composition affects the hygroscopic growth of aerosol particles, again affecting their radiative influences and ability to form cloud droplets. For these reasons the ability to characterize particle size and size-dependent composition and to represent these properties in large-scale chemical transport models is essential. Current climate models, which in most cases consider only sulfur chemistry, cannot be tested adequately for want of accurate treatment of aerosol influences, despite their potential importance. This chapter reviews the substantial progress that has been made over the past decade in characterizing aerosols, their properties and distributions, and in understanding the controlling processes. These developments point to a highly exciting future for aerosol research as a component of integrative studies of atmospheric chemistry.
This page was last updated 2003-08-22.
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