Assessing the impact of shipping emissions on air pollution in the Canadian Arctic and northern regions: current and future modelled scenarios
Wanmin Gong, Stephen R. Beagley, Sophie Cousineau, Mourad Sassi, Rodrigo Munoz-Alpizar, Sylvain Ménard, Jacinthe Racine, Junhua Zhang, Jack Chen, Heather Morrison, Sangeeta Sharma, Lin Huang
(+5 others)
2018
Atmospheric Chemistry and Physics Discussions
<p><strong>Abstract.</strong> 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), to investigate the contribution from the marine shipping emissions over the Canadian Arctic
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... waters (at both present and projected future levels) to ambient concentrations of criteria pollutants (O<sub>3</sub>, PM<sub>2.5</sub>, NO<sub>2</sub>, and SO<sub>2</sub>), atmospheric deposition of sulphur and nitrogen, atmospheric loading and deposition of black carbon 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 O<sub>3</sub> and PM<sub>2.5</sub> 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 well the observed O<sub>3</sub> and PM components 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<span class="thinspace"></span>% of ambient O<sub>3</sub> concentration over the eastern Canadian Arctic and between 1 and 5<span class="thinspace"></span>% of ambient PM<sub>2.5</sub> concentration over the shipping channels. Arctic shipping emissions make a much greater contributions to the ambient NO<sub>2</sub> and SO<sub>2</sub> concentrations, at 10&ndash;50<span class="thinspace"></span>% and 20&ndash;100<span class="thinspace"></span>%, respectively. At the projected 2030 business-as-usual (BAU) level, the impact of Arctic shipping emissions is predicted to increase to up to 5<span class="thinspace"></span>% in ambient O<sub>3</sub> concentration over a broad region of the Canadian Arctic and to 5&ndash;20<span class="thinspace"></span>% in ambient PM<sub>2.5</sub> 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 population-weighted concentration of SO<sub>2</sub> and PM<sub>2.5</sub> would be brought down to below the current level. The contribution of Canadian Arctic shipping to the atmospheric deposition of sulphur and nitrogen is small at the current level, <<span class="thinspace"></span>5<span class="thinspace"></span>%, but is expected to increase to up to 20<span class="thinspace"></span>% for sulphur and 50<span class="thinspace"></span>% 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, <<span class="thinspace"></span>0.1<span class="thinspace"></span>% on average and up to 2<span class="thinspace"></span>% locally over eastern Canadian Arctic for the former, and between 0.1 and 0.5<span class="thinspace"></span>% 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<span class="thinspace"></span>% on BC column loading and locally exceeding 30<span class="thinspace"></span>% 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.</p>
doi:10.5194/acp-2018-125
fatcat:sakqbs7hlnd7fhyivbhdcsiy2m
