Polycyclic aromatic compounds (PACs) in the Canadian environment: Sources and emissions

• Published in: Environmental pollution (1987) 2021-01, Vol.269, p.116008, Article 116008
• Main Authors: Berthiaume, A., Galarneau, E., Marson, G.
• Format: Article
• Language: English
• Subjects: Air Pollutants - analysis; Canada; Ecosystem; Emissions; Environmental Monitoring; Humans; Pollutant inventories; Polycyclic aromatic compounds (PACs); Polycyclic aromatic hydrocarbons (PAHs); Polycyclic Aromatic Hydrocarbons - analysis; Polycyclic Compounds; Sources
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2020.116008

Twenty-five years after the first look at polycyclic aromatic compounds (PACs) in Canada, this article presents current knowledge on Canadian PAC emission sources. The analysis is based on national inventories (the National Pollutant Release Inventory (NPRI) and the Air Pollutant Emissions Inventory (APEI)), an analysis of Canadian forest fires, and several air quality model-ready emissions inventories. Nationally, forest fires continue to dominate PAC emissions in Canada, however there is uncertainty in these estimates. Though forest fire data show a steady average in the total annual area burned historically, an upward trend has developed recently. Non-industrial sources (home firewood burning, mobile sources) are estimated to be the second largest contributor (∼6-8 times lower than forest fires) and show moderate decreases (25%–65%) in the last decades. Industrial point sources (aluminum production, iron/steel manufacturing) are yet a smaller contributor and have seen considerable reductions (90% +) in recent decades. Fugitive emissions from other industrial sources (e.g. disposals by the non-conventional oil extraction and wastewater sectors, respectively) remain a gap in our understanding of total PAC emissions in Canada. Emerging concerns about previously unrecognized sources such as coal tar-sealed pavement run-off, climate change are discussed elsewhere in this special issue. Results affirm that observations at the annual/national scale are not always reflective of regional/local or finer temporal scales. When determining which sources contribute most to human and ecosystem exposure in various contexts, examination at regional and local scales is needed. There is uncertainty overall in emissions data stemming in part from various accuracy issues, limitations in the scope of the various inventories, and inventory gaps, among others. [Display omitted] •PACs in Canada are from forest fires, home firewood burning, vehicles and industry.•Priority sources at regional scales often differ from national/provincial scales.•PAC inventories are shaped by scope, timing, inputs, and granularity, among others.•Future directions to improve understanding of PAC sources are suggested. Capsule: This review assesses emission sources and trends of polycyclic aromatic compounds (PACs) in Canada.