Multiple studies have documented that the transport of Asian pollution is initiated by cold frontal passages over eastern Asia, which lift continental boundary layer air to the free troposphere where it is then
carried toward North America by the westerlies [Jacob et al., 1999; Jaffe et al., 1999]. Transpacific transport is highly episodic but most frequent and rapid in spring [Yienger et al., 2000], evidence also suggests that Asian influences are present throughout the year [VanCuren et al., 2004].