In this paper we consider the properties of fractal aggregates suspended in the Earth atmosphere. Fractal aggregates (FA) are now well established to appear in numerous natural and anthropogenic processes. Their role in the atmosphere is immense, for FA possess anomalous physico-chemical, mechanical and optical properties making them extremely effective atmospheric agents. The main goal of this paper is to overview the mechanisms of FA formation, their properties, to discuss sources and sinks of the atmospheric FA and their possible contribution into intra-atmospheric processes and influence on the public health.