Dioxins I. Dynamics and legal directives in Europe.

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans are a group of aromatic hydrocarbons, emitted mostly from anthropogenic sources, that have negative effects on human health. Chlorine and carbon compounds, in combination with temperature and combustion processes, are the main factors in the production of these products that, depending on their structural configuration and formation conditions, may have higher or lower impact in the environment, along the different phases of emission, ambient distribution, final deposition and absorption. Given their potential negative effect on human health, the importance of gaining better knowledge and analysing emission patterns of dioxins from different sources is critical in order to observe the actual trend of transmission of dioxins around the world and take measures to reduce their emission and minimize their impact in the atmosphere. For these reasons, the main objective of this chapter is to provide a basic outline about the dioxin situation, going briefly through the historical evolution of dioxin emissions in order to understand the change in perception towards this chemical agent, followed by a description of the main sources of these pollutants, as well as the typical emission patterns and the most important factors that can affect ambient distribution. The production and formation of these compounds has been followed by important research on different minimization and abatement technologies, to reduce the formation and emission of dioxins to the atmosphere, in order to meet legal emission standards that become more restrictive over the years.