10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Elemental Carbon Observations over Canada (2006-2015): Constraining on Regional Emissions in North America
LIN HUANG, Tak Chan, Knut von Salzen, Richard Leaitch, Sangeeta Sharma, Wendy Zhang, Darrell Ernst, Junhua Zhang, Michael Moran, Jeff Brook, Anne Marie Macdonald, Michael Wheeler, Environment & Climate Change Canada, ASTD, Toronto, Canada
Abstract Number: 1615 Working Group: Aerosols in Earth System
Abstract Due to its unique physical properties, black carbon (BC) plays an important role in Earth climate system from regional to global scales. To contribute to the evaluation of models, which may help constrain regional and global emissions, an observation network of aerosol elemental carbon (EC) as BC mass has been strategically established over Canada since 2006, with most of the sites co-locating with aerosol optical observations, and GHG measurements. These sites represent different geographic locations with various continental source influences, from urban location (as Downsview /Toronto) to rural area (as Egbert, ON), then to boreal forest (as Fraserdale, ON, in eastern Canada, and East Trout Lake, SK, in western Canada) and from a high elevated site (as Whistler Mt. BC) to a remote area (as Alert, NU, an Arctic site). Because of its short atmospheric life-time, the changes in atmospheric EC concentration (specifically in seasonal and inter-annual variability) are largely reflecting the changes of emission source influences at regional scales though the impacts from atmospheric long-range transport could not be underestimated.
Weekly integrated quartz filter samples collected at these sites have been analysed for EC concentrations over the period of 2006 to 2015. Seasonal patterns and inter-annual variability of BC mass have been obtained across the sites. In comparison with several recently published emission inventories, including the historic IPCC emissions of BC for CMIP6 and Canada /US PM2.5 emissions, it is suggested that the trends observed at the sites in eastern Canada (e.g., Downsview/Toronto, and Egbert, ON) have been dominantly caused by anthropogenic emission changes and the influence from US emissions on these sites may be stronger than from Canadian emissions, whereas that the seasonal pattern and inter-annual variability observed at the sites in western Canada (e.g., ETL) have been influenced much more by biomass burning emissions. The decreasing trends (2006-2015) in eastern Canada would imply beneficial effects from clean air policies both from US (Clean Air Act) and Canada (Clean Air Regulatory Agenda) except that there are inconsistencies between seasonal patterns observed in eastern Canada and North American emissions inventories. The inconsistency reveals open questions and may suggest a possible pathway on constraining the seasonal profile of BC emissions in North America via observations.
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