“…Three primary mechanisms can loft pollutants from the boundary layer to the free troposphere: (1) airstreams such as the warm conveyor belt (WCB) that are associated with middle latitude cyclones (Bey et al, 2001;Cooper et al, 2002;Hannan et al, 2003;Kiley and Fuelberg, 2006), (2) orographic lifting (Henne et al, 2004;Chen et al, 2009;Ding610 C. A. Klich and H. E. Fuelberg: Transport of CO in a middle latitude cyclone latitudes (Stohl et al, 2002), distinct maxima are located off the east coasts of North America and Asia (Stohl, 2001;Eckhardt et al, 2004). The long-range synoptic-scale WCBrelated transport of atmospheric pollutants has been studied across both the Pacific Ocean (e.g., Jaffe et al, 1999;Yienger et al, 2000;Bey et al, 2001;Carmichael et al, 2003;Heald et al, 2003;Jacob et al, 2003;Liu et al, 2003;Cooper et al, 2004) and Atlantic Ocean (Stohl and Trickl, 1999;Cooper et al, 2001Cooper et al, , 2002Naja et al, 2003;Li et al, 2005;Fehsenfeld et al, 2006;Singh et al, 2009).…”