Natural surface emissions dominate anthropogenic emissions contributions to total gaseous mercury at Canadian rural sites

<p>The Canadian Air and Precipitation Monitoring Network (CAPMoN) measures total gaseous mercury (TGM) at three rural–remote sites. Long-term TGM measurements, ancillary measurements, and the positive matrix factorization (PMF) model were used to assess temporal changes in anthropogenic and na...

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Main Authors: I. Cheng, A. Cole, L. Zhang, A. Steffen
Format: Article
Language:English
Published: Copernicus Publications 2025-08-01
Series:Atmospheric Chemistry and Physics
Online Access:https://acp.copernicus.org/articles/25/8591/2025/acp-25-8591-2025.pdf
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author I. Cheng
A. Cole
L. Zhang
A. Steffen
author_facet I. Cheng
A. Cole
L. Zhang
A. Steffen
author_sort I. Cheng
collection DOAJ
description <p>The Canadian Air and Precipitation Monitoring Network (CAPMoN) measures total gaseous mercury (TGM) at three rural–remote sites. Long-term TGM measurements, ancillary measurements, and the positive matrix factorization (PMF) model were used to assess temporal changes in anthropogenic and natural surface emission (wildfires plus re-emitted Hg) contributions to TGM and examine the emission drivers of the observed TGM trends between 2005 and 2018. TGM showed decreasing trends at all sites; the magnitudes (ng m<span class="inline-formula"><sup>−3</sup></span> yr<span class="inline-formula"><sup>−1</sup></span>) were <span class="inline-formula">−</span>0.050 at Saturna for 2010–2015, <span class="inline-formula">−</span>0.026 at Egbert for 2005–2018, and <span class="inline-formula">−</span>0.014 at Kejimkujik for 2005–2016. The increasing contributions from natural surface Hg emissions at Saturna (1.8 % yr<span class="inline-formula"><sup>−1</sup></span>) and Kejimkujik (0.3 % yr<span class="inline-formula"><sup>−1</sup></span>) resulted from declining anthropogenic Hg emissions and increasing oceanic re-emissions. The mean relative contributions of natural surface emissions to annual TGM were 71 %, 77.5 %, and 64 % at Saturna, Egbert, and Kejimkujik. TGM at Saturna was mainly from the Hg pool (50 %), terrestrial re-emissions (26 %), and shipping (10 %); at Egbert, from the Hg pool (66 %), terrestrial re-emissions (24 %), and crustal/soil dust (5 %); and at Kejimkujik, from the Hg pool (81 %), regional Hg emissions (11 %), and oceanic re-emissions (8 %). Local combustion contributed a few percent of the annual TGM, while the oceanic re-emission contribution was 6 %–8 % for the two coastal sites. Wildfire impacts on annual TGM were 3.7 % for Saturna and 1.6 % for Egbert. The Hg pool contributions to TGM were greater in the cold season, whereas wildfire and surface re-emission contributions can be significant in the warm season.</p>
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spelling doaj-art-b290fc9e6df0479eb42646779468df482025-08-20T03:45:11ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242025-08-01258591861110.5194/acp-25-8591-2025Natural surface emissions dominate anthropogenic emissions contributions to total gaseous mercury at Canadian rural sitesI. Cheng0A. Cole1L. Zhang2A. Steffen3Measurements and Analysis Research Section, Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, M3H 5T4, CanadaMeasurements and Analysis Research Section, Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, M3H 5T4, CanadaMeasurements and Analysis Research Section, Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, M3H 5T4, CanadaProcesses Research Section, Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, M3H 5T4, Canada<p>The Canadian Air and Precipitation Monitoring Network (CAPMoN) measures total gaseous mercury (TGM) at three rural–remote sites. Long-term TGM measurements, ancillary measurements, and the positive matrix factorization (PMF) model were used to assess temporal changes in anthropogenic and natural surface emission (wildfires plus re-emitted Hg) contributions to TGM and examine the emission drivers of the observed TGM trends between 2005 and 2018. TGM showed decreasing trends at all sites; the magnitudes (ng m<span class="inline-formula"><sup>−3</sup></span> yr<span class="inline-formula"><sup>−1</sup></span>) were <span class="inline-formula">−</span>0.050 at Saturna for 2010–2015, <span class="inline-formula">−</span>0.026 at Egbert for 2005–2018, and <span class="inline-formula">−</span>0.014 at Kejimkujik for 2005–2016. The increasing contributions from natural surface Hg emissions at Saturna (1.8 % yr<span class="inline-formula"><sup>−1</sup></span>) and Kejimkujik (0.3 % yr<span class="inline-formula"><sup>−1</sup></span>) resulted from declining anthropogenic Hg emissions and increasing oceanic re-emissions. The mean relative contributions of natural surface emissions to annual TGM were 71 %, 77.5 %, and 64 % at Saturna, Egbert, and Kejimkujik. TGM at Saturna was mainly from the Hg pool (50 %), terrestrial re-emissions (26 %), and shipping (10 %); at Egbert, from the Hg pool (66 %), terrestrial re-emissions (24 %), and crustal/soil dust (5 %); and at Kejimkujik, from the Hg pool (81 %), regional Hg emissions (11 %), and oceanic re-emissions (8 %). Local combustion contributed a few percent of the annual TGM, while the oceanic re-emission contribution was 6 %–8 % for the two coastal sites. Wildfire impacts on annual TGM were 3.7 % for Saturna and 1.6 % for Egbert. The Hg pool contributions to TGM were greater in the cold season, whereas wildfire and surface re-emission contributions can be significant in the warm season.</p>https://acp.copernicus.org/articles/25/8591/2025/acp-25-8591-2025.pdf
spellingShingle I. Cheng
A. Cole
L. Zhang
A. Steffen
Natural surface emissions dominate anthropogenic emissions contributions to total gaseous mercury at Canadian rural sites
Atmospheric Chemistry and Physics
title Natural surface emissions dominate anthropogenic emissions contributions to total gaseous mercury at Canadian rural sites
title_full Natural surface emissions dominate anthropogenic emissions contributions to total gaseous mercury at Canadian rural sites
title_fullStr Natural surface emissions dominate anthropogenic emissions contributions to total gaseous mercury at Canadian rural sites
title_full_unstemmed Natural surface emissions dominate anthropogenic emissions contributions to total gaseous mercury at Canadian rural sites
title_short Natural surface emissions dominate anthropogenic emissions contributions to total gaseous mercury at Canadian rural sites
title_sort natural surface emissions dominate anthropogenic emissions contributions to total gaseous mercury at canadian rural sites
url https://acp.copernicus.org/articles/25/8591/2025/acp-25-8591-2025.pdf
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