Atmospheric polycyclic aromatic hydrocarbons in the Canadian Athabasca oil sands region: emission database update and assessment of contributions of oil sands sources to ambient concentrations

Environ Pollut. 2025 Dec 13:127535. doi: 10.1016/j.envpol.2025.127535. Online ahead of print.

ABSTRACT

An existing emission database for 16 polycyclic aromatic hydrocarbons (PAHs) covering the Athabasca oil sands region (AOSR) of Alberta, Canada was updated using the latest knowledge reported in literature and then validated using ambient concentration measurements through dispersion modeling. The revised domain-total emission of the total of 15 PAH species (∑15PAHs, excluding naphthalene) was 25.3 tonnes/yr, of which phenanthrene (9.4 tonnes/yr), fluorene (4.2), acenaphthene (2.9), pyrene (2.4), and fluoranthene (1.9) were the dominant species. Emission source sectors quantified in this study include point sources (7.9 tonnes/yr), mine fleet (6.5), residential and commercial (3.7), local traffic and airport (3.4), tailings ponds (1.8), fugitive dust (1.6), and agriculture controlled burning (0.4). The revised domain-total naphthalene emission was 56.3 tonnes/yr. With this emission database as input, the dispersion model-predicted concentrations were comparable with passive-sampling measurements; specifically, modeled annual concentration of ∑15PAHs was only ∼4% lower than measurements at seven local sites and ∼17% lower at nine remote sites. The emission sectors were regrouped into Oil Sands (OS) sources and non-Oil Sands (non-OS) sources to conduct dispersion model sensitivity tests. OS sources contributed ∼70% to the domain-averaged ambient concentration of ∑15PAHs. Areas north of Fort McMurray, especially those close to or downwind of tailings ponds and active mining pits, had OS source contributions exceeding 50%, while areas south of Fort McMurray were mainly impacted by non-OS sources.

PMID:41397494 | DOI:10.1016/j.envpol.2025.127535