MILJØ2015-Norsk miljøforskning mot 2015

Persistent Organic Pollutants (POPs) are a subgroup of organic contaminants. POP substances often have 3 characteristics in common (i) one or more cyclical ring structures of either aromatic or aliphatic nature, (ii) a lack of polar functional groups, and (iii) a variable amount of halogen substitutions, usually chlorine. Typically, POPs are long-lived in the environment (persistent), lipophilic (bio-accumulative), occur to a significant extent in both the gas phase and condensed states (semi-volatile), a nd are toxic. To date, two entirely different modelling approaches (multimedia fate models and atmospheric transport models) have been developed and tested to understand and predict the long-range atmospheric transport behaviour of POPs. This project w ill combine the best of both worlds by implementing processes normally treated in multimedia fate models into the atmospheric transport model FLEXPART. FLEXPART is a widely used Lagrangian particle dispersion model that has been developed by one of the ap plicants but has not yet been used for POP modelling. After implementing POP processes into FLEXPART, the model shall be run in a receptor-oriented mode backward in time for a large number of POP samples taken at Norwegian and Canadian measurement statio ns. The model performance will then be evaluated against the measurement data. In order to validate the success of the pure transport part of the simulation, measurements of other pollutants such as carbon monoxide (which is known to be affected mainly by transport) will be considered as well. The remaining differences between the measurement data and the model can then be attributed mainly to errors in the treatment of POP-relevant processes (e.g., re-volatilization, deposition, chemical degradation). Th is will yield new insights into the processes determining the atmospheric transport of POPs. Finally, in order to improve POP emission estimates, the model will be used for inverse modeling of POP emissions