Identification and characterization of inland ship plumes over Vancouver, BC

There is increasing concern regarding the impact of marine vessel emissions on the air quality of coastal areas and their relative impact is increasing as emissions from other sources decrease and shipping activities increase. Marine vessels contain a variety of large diesel engines and in a relatively large number of areas they are currently not restricted from using fuels with a high sulphur content. In August 2001 during the Pacific 2001 study, which included the port city of Vancouver, British Columbia, a large suite of gas and particle measurements were obtained with high time resolution. Among a total of 29 SO2 episodes observed >5 km inland during a period of 15 days, eight were caused by local emissions sources and four were identified as relatively fresh ship plumes. These ship plumes were indicated by an increase of SO2 above 9 ppbv typically lasting for a few hours. They were accompanied by increases in NOx, NO, CO, VOCs, particle counts (5-200 nm), black carbon and PM2.5. Only one plume occurred when an Aerodyne aerosol mass spectrometer (AMS) was in operation and this event is studied in detail. Ultrafine (