Assessing the impact of shipping emissions on air pollution in the Canadian Arctic and northern regions: current and future modelled scenarios

Abstract

Abstract. A first regional assessment of the impact of shipping emissions on air pollution in the Canadian Arctic and northern regions was conducted in this study. Model simulations were carried out on a limited-area domain (at 15 km horizontal resolution) centred over the Canadian Arctic, using the Environment and Climate Change Canada's on-line air quality forecast model, GEM-MACH (Global Environmental Multi-scale – Modelling Air quality and CHemistry), to investigate the contribution from the marine shipping emissions over the Canadian Arctic waters (at both present and projected future levels) to ambient concentrations of criteria pollutants (O3, PM2.5, NO2, and SO2), atmospheric deposition of sulfur (S) and nitrogen (N), and atmospheric loading and deposition of black carbon (BC) in the Arctic. Several model upgrades were introduced for this study, including the treatment of sea ice in the dry deposition parameterization, chemical lateral boundary conditions, and the inclusion of North American wildfire emissions. The model is shown to have similar skills in predicting ambient O3 and PM2.5 concentrations in the Canadian Arctic and northern regions, as the current operational air quality forecast models in North America and Europe. In particular, the model is able to simulate the observed O3 and PM components well at the Canadian high Arctic site, Alert. The model assessment shows that, at the current (2010) level, Arctic shipping emissions contribute to less than 1 % of ambient O3 concentration over the eastern Canadian Arctic and between 1 and 5 % of ambient PM2.5 concentration over the shipping channels. Arctic shipping emissions make a much greater contributions to the ambient NO2 and SO2 concentrations, at 10 %–50 % and 20 %–100 %, respectively. At the projected 2030 business-as-usual (BAU) level, the impact of Arctic shipping emissions is predicted to increase to up to 5 % in ambient O3 concentration over a broad region of the Canadian Arctic and to 5 %–20 % in ambient PM2.5 concentration over the shipping channels. In contrast, if emission controls such as the ones implemented in the current North American Emission Control Area (NA ECA) are to be put in place over the Canadian Arctic waters, the impact of shipping to ambient criteria pollutants would be significantly reduced. For example, with NA-ECA-like controls, the shipping contributions to the population-weighted concentrations of SO2 and PM2.5 would be brought down to below the current level. The contribution of Canadian Arctic shipping to the atmospheric deposition of sulfur and nitrogen is small at the current level, < 5 %, but is expected to increase to up to 20 % for sulfur and 50 % for nitrogen under the 2030 BAU scenario. At the current level, Canadian Arctic shipping also makes only small contributions to BC column loading and BC deposition, with < 0.1 % on average and up to 2 % locally over the eastern Canadian Arctic for the former, and between 0.1 % and 0.5 % over the shipping channels for the latter. The impacts are again predicted to increase at the projected 2030 BAU level, particularly over the Baffin Island and Baffin Bay area in response to the projected increase in ship traffic there, e.g., up to 15 % on BC column loading and locally exceeding 30 % on BC deposition. Overall, the study indicates that shipping-induced changes in atmospheric composition and deposition are at regional to local scales (particularly in the Arctic). Climate feedbacks are thus likely to act at these scales, so climate impact assessments will require modelling undertaken at much finer resolutions than those used in the existing radiative forcing and climate impact assessments.

Local Arctic Air Pollution: A Neglected but Serious Problem

“…More recent Arctic‐wide simulations using the Winther et al () emissions investigated the impacts of future shipping and found significant increases in ozone concentrations particularly along the northern Norwegian coast, the Barents Sea, and off the northern coast of Alaska (Law et al, ) in line with prior estimates (Dalsøren et al, ; Granier et al, ). A recent study focusing on the impacts of Canadian shipping along the NWP found limited present‐day effects on aerosols and ozone but potentially large effects based on a business as usual scenario for 2030 with up to 5% increases in ozone and 5 to 20% in PM 2.5 along shipping corridors (Gong et al, ). Browse et al () investigated the deposition of BC from future Arctic shipping in 2050 based on the scenarios from Corbett et al ().…”

Space‐Based Observations for Understanding Changes in the Arctic‐Boreal Zone

“…There may be an increase in future pollution emissions within the ABZ given the likely increase in wildfires, agricultural fires, and anthropogenic activities (e.g., shipping, oil and natural gas extraction, fishing) in the warmer and increasingly accessible ABZ (e.g., Arnold et al, ; Corbett et al, ; Gong et al, ; Hegg et al, ; Law et al, ; Marelle et al, ; McKuin & Campbell, ; Peters et al, ; Schmale et al, ). There are several international efforts that have as part of their design to observe these changes.…”

The Atmospheric Imaging Mission for Northern Regions: AIM-North

“…The compounds thought to be responsible for the majority of these deaths are ground level ozone, NO 2 , and particulate matter (PM). It is this realization that prompted Canada to formulate an Air Quality Health Index (AQHI) (Gillett et al 2004), which uses the concentrations of these three pollutants to define a scale (ranging from 0 to 10þ) to help Canadians understand what the air quality around them means to their health. These pollutants, along with others such as SO 2 , formaldehyde, and carbon monoxide (CO), result (directly or indirectly) from combustion.…”

“…Wildfires are particularly intense sources of air pollution in the spring and summer. While variable from year-to-year, there has been an increase in the number and severity of fires in Canada over the past half-century and this is expected to continue with the warming climate (Gillett et al 2004;Kirchmeier-Young et al 2017. Changing fire regimes in Canada's boreal forests are expected to result in increasing fire frequency and severity (Veraverbeke et al 2017) as well as a northward march in large fires with associated impacts to air quality, human health and decreased carbon storage (Bond-Lamberty et al 2007;Brandt 2009;Kurz et al 2013).…”

“…Further, with the accelerating disappearance of multi-year ice, Arctic sea routes are more readily negotiated by large container ships. In the coming years, increased marine traffic through the Arctic, in an attempt to reduce fuel used in long journeys, could impact air quality by increasing ozone, NO 2 , SO 2 , and increasing the abundance of aerosols (Gong et al 2018) which will likely affect cloud formation.…”