Sunphotometry, supported by TOMS imagery and the NRL-NAAPS global aerosol model, was used to monitor the 2001 springtime Asian dust plume across Canada and the U.S. Comparative analysis between these data sets indicated that the dust plume was remarkable in its extent and persistence and that its evolution could be inferred at western, mid-western and eastern sunphotometer stations for a period of about a week. The dust influence on sunphotmeter monthly statistics is shown to be weak, but systematic.