AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Receptor Modeling of Ambient PM2.5 Collected at the National Air Pollution Surveillance (NAPS) Speciation Sites in Ontario for the Years 2005 -2010
UWAYEMI SOFOWOTE, Yushan Su, Ewa Dabek-Zlotorzynska, Ankit Rastogi, Jeff Brook, AQARU, EMRB, Ontario Ministry of the Environment
Abstract Number: 256 Working Group: Source Apportionment
Abstract The Canadian National Air Pollution Surveillance (NAPS) network operates five fine particulate matter (PM2.5) speciation sites in Ontario all of which are located in the southern part of the province. Data from these speciation sites from 2005 to 2010 were subjected to positive matrix factorization (PMF) to obtain factors of particulate matter pollution. Up to eight factors were found to be common across two or more sites. These factors were identified with sulphate-rich emissions, nitrate-rich emissions, metal works emissions, crustal matter, calcium-rich emissions, arsenic-rich emissions, wood combustion and oil processing and combustion emissions. On average, sulphate and nitrate related emissions contributed 56% of the total PM2.5 mass across these speciation sites and their temporal variations showed summer and wintertime enrichment respectively. The sulphate factor which is largely energy-related has been on a decline since its peak in 2007. A 10 – 35% reduction in average sulphate contribution observed from 2007 to 2008 across four of the 5 speciation sites may be an indicator of the downturn in the global economy in 2008. Simplified quantitative transport bias analysis (sQTBA) was used to reveal potential source regions of contributions of factors that were common to all five speciation sites in the province. Local areas were dominant sources of contributions from the sulphate factor but regional source areas including the US Midwest, east coast as well as areas in southern states were also observed while the nitrate factor had its strongest source areas around the southernmost parts of Lake Erie. This work shows that the hybrid PMF-sQTBA receptor modeling approach is an effective source apportionment tool for regional pollutants affecting multiple sites.