Scope of CARIBIC

Where does the air come from in which we fly ?
This is a very interesting question. In the figure you see how the air has traveled during 5 days before it arrived just there where the LTU CARIBIC aircraft was flying. In the tropics, near the Gulf of Mexico, the air moves slowly. We measure tropical air. This air contained much pollution from very large forest fires. When coming closer to Europe the air we meet has traveled from as far as North East America. This air can contain pollution originating from this continent.