Persistent Organic Pollutants in the European Atmosphere

Abstract

Since the beginning of the last century, European air has received increasing amounts of organic compounds. Some of them were released as consequence of combustion processes and others were synthesised for specific applications in industry or agriculture. A group of these organic compounds are semi-volatile, resistant to degradation processes, bioaccumulative and toxic. Because of these properties, they are grouped under the general name of persistent organic pollutants (POPs). These physical-chemical properties are found in polycyclic aromatic hydrocarbons or in organic molecules with 5-12 carbon atoms and a high degree of halogen substituents. The present chapter is devoted to describe these two groups of compounds. However, in other review papers, only the organohalogen compounds are considered under the POP concept.The properties of semi-volatility, bioaccumulation and persistent to degradation processes provide a potential for long-range atmospheric transport of these compounds. They may therefore be deleterious for the ecosystems and human health even in sites located far away from the areas of production and application. Furthermore, nearly all organohalogen POPs are man-made. In nature, there are no compounds with similar chemical structure (or these are in very low concentrations). Thus, human and animal evolution has not had the opportunities to generate specific metabolic ways for their elimination. Thus, they accumulate and remain in the body throughout all life and during all life stages (including in utero development). By the end of the twentieth century, international protocols have been established to reduce the emissions and impact of POPs into the environment and humans.The following chapter describes the changes in concentration of POPs in ambient air in Europe through time, with a focus on current concentrations. It also describes the differences in physical-chemical properties of these pollutants and relates them with the mechanisms of atmospheric transport. Strategies to reduce the ambient air concentrations are discussed. Information is also given on future perspectives in view of "emerging" pollutants and emission sources.