Environmentally safe areas and routes in the Baltic proper using Eulerian tracers

► We model oil spills using a large ensemble of passive Eulerian tracers. ► A number of measures are designed to evaluate the severeness of spill locations. ► Environmentally optimal maritime routes through the Baltic proper are constructed. ► Ships should follow a route south of Bornholm and not north of as today. ► There are seasonal cycles but their effect on the studied routes are minor.