Emerging environmental substances are not necessarily new chemicals. They are substances that have often long been present in the environment but whose presence and significance are only now being elucidated. NORMAN has identified a list of the currently most frequently discussed emerging substances and emerging pollutants. These substances are selected by the NORMAN Prioritisation Working Group, based on citations in the scientific literature, and taking into account the definition of "emerging substances" and "emerging pollutants" given in the NORMAN Glossary of terms.

NORMAN systematically collects in the EMPODAT database monitoring data and information on effects and hazardous properties for these substances. On the basis of this information, the substances are assigned to priority action categories by the NORMAN Prioritisation Working Group.  "Emerging substances" can be defined as substances that have been detected in the environment, but which are currently not included in routine monitoring programmes at EU level and whose fate, behaviour and (eco)toxicological effects are not well understood. "Emerging pollutants" can be defined as pollutants that are currently not included in routine monitoring programmes at the European level and which may be candidates for future regulation, depending on research on their (eco)toxicity, potential health effects and public perception and on monitoring data regarding their occurrence in the various environmental compartments. Examples from the LIST OF EMERGING SUBSTANCES are surfactants, flame retardants, pharmaceuticals and personal care products, gazoline additives and their degradation products, biocides, polar pesticides and their degradation products and various proven or suspected endocrine disrupting compounds (EDCs). The NORMAN experts regularly revise the list of emerging substances.