The standard covers flue gas cleaning processes for the removal of inorganic trace species (e.g. metals like mercury and their compounds) and organic trace species (e.g. PAHs, PCDD/F, PCBs). The descriptions apply primarily to combustion flue gases from large combustions plants (LCP) for energy conversion and waste incinerators as per the 13th or 17th BImSchV (German Federal Immission Control Ordinance). Following a detailed description of the physical and chemical fundamentals of these substance groups or selected individual species, state-of-the art process techniques for their removal from combustion flue gases are presented and explained in more detail by practical examples. The standard applies to plant operators and manufacturers, methods engineers as well as to controlling and surveillance authorities.