By: Ryan Glover
As part of the ACSD seminar series work, AirZone presented its work on POPs research on November 25th, 2003 at the McTaggart-Cowan Auditorium. For more information visit the website at .
By: H. Hung(1), P. Blanchard(1), C. Halsall(2), J. Ma(1), P. Fellin(3), H. Li(3), G. Stern(4), B. Rosenberg(4) and S. Friesen(4)
1: Meteorological Service of Canada, Downsview, Canada
2: Lancaster University, Lancaster, U. K.
3: AirZone, Mississauga, Canada
4: Fresh Water Institute, Winnipeg, Canada
Date: Tuesday, November 25, 2003
Location: McTaggart-Cowan Auditorium
Abstract:
The Northern Contaminants Program (NCP) baseline monitoring project was established in 1992 to monitor for POPs in Arctic air. Under this project, weekly samples of air were collected at four Canadian and two Russian arctic sites, namely Alert, Nunavut (1992-ongoing); Tagish, Yukon (Dec 1992 – Mar 1995); Little Fox Lake, Yukon (2002-2003); Kinngait, Nunavut (Mar 1994 – Feb 1996, Oct 2000 – Sep 2002); Dunai Island, Russia (Apr 1993 – May 1995) and Amderma, Russia (1999-2001). Selected POPs, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticides, were analyzed in both the gas and particulate phases.
Various studies have been conducted to analyze and interpret the results obtained under this project. These studies include (1) the development of temporal trends for atmospheric PCBs and OCs, (2) the measurement of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in arctic air, (3) the use of a global distribution model to interpret observed PCB air concentrations, (4) the spatial variabilities in OCs seasonal cycles observed at four Arctic stations, and (5) the correlation of POP air concentrations with large-scale climate variation patterns.
(1) The digital filtration technique (Nakazawa et al., 1997) was used to develop temporal trends and seasonal cycles for PCBs and OCs measured at Alert in the Canadian High Arctic, between 1993 and 1999. Different PCB congeners showed different rates of decline in arctic air which may be related to the physical chemical properties of the congeners. As for the OCs, pesticides that have been banned in western industrialized countries, e.g. a-hexachlorocyclohexane (a-HCH), generally showed declining or steady trends in arctic air while current-use pesticides, such as Endosulfan I, showed very slight decline in concentrations.
(2) PCDD/F concentrations in air at Alert were measured under a special study conducted in the winter of 2000/2001. Back-trajectory analysis revealed that high concentrations of these compounds observed in Alert air probably originated from Siberia.
(3) Using the global emission inventory of PCBs and the GloboPOP model, which is a zonally-averaged global transport model for POPs, the
relative rates of decline of atmospheric PCBs observed at Alert and Eagle Harbour, Lake Superior, were reproduced. It was found that the half-life profiles observed at Alert and Eagle Harbour mimic the half-life profile of emission extremely well. This implies that air is only a transport medium and POP levels in air at remote locations vary according to the rate of emission.
(4) Four sites, Kinngait and Alert in Nunavut, Tagish in Yukon and Dunai Island in Russia, were operating simultaneously between 1993 and 1994. The seasonality of selected OCs was examined during this period. Spring high concentration “events” were observed for both “past-” and “current-use” pesticides at Dunai and Kinngait but not at Tagish and Alert.
(5) Measured air concentrations of selected POPs at Alert were found to be strongly associated with atmospheric low-frequency fluctuations, notably the Pacific North American (PNA) pattern, the West Pacific pattern (WP), Scandinavia pattern (SCA) and the East Atlantic/West Russia pattern (EA/WR)
Plans for future studies were be presented at the seminar.
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