Unexpected anthropogenic emission decreases explain recent atmospheric mercury concentration declines

Feinberg, Aryeh; Selin, Noelle E.; Braban, Christine F. ORCID: https://orcid.org/0000-0003-4275-0152; Chang, Kai-Lan; Custódio, Danilo; Jaffe, Daniel A.; Kyllönen, Katriina; Landis, Matthew S.; Leeson, Sarah R.; Luke, Winston; Molepo, Koketso M.; Murovec, Marijana; Nerentorp Mastromonaco, Michelle G.; Aspmo Pfaffhuber, Katrine; Rüdiger, Julian; Sheu, Guey-Rong; St. Louis, Vincent L.. 2024 Unexpected anthropogenic emission decreases explain recent atmospheric mercury concentration declines. Proceedings of the National Academy of Sciences, 121 (42), e2401950121. 11, pp. https://doi.org/10.1073/pnas.2401950121

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Official URL: http://dx.doi.org/10.1073/pnas.2401950121

Abstract/Summary

Anthropogenic activities emit ~2,000 Mg y−1 of the toxic pollutant mercury (Hg) into the atmosphere, leading to long-range transport and deposition to remote ecosystems. Global anthropogenic emission inventories report increases in Northern Hemispheric (NH) Hg emissions during the last three decades, in contradiction with the observed decline in atmospheric Hg concentrations at NH measurement stations. Many factors can obscure the link between anthropogenic emissions and atmospheric Hg concentrations, including trends in the reemissions of previously released anthropogenic (“legacy”) Hg, atmospheric sink variability, and spatial heterogeneity of monitoring data. Here, we assess the observed trends in gaseous elemental mercury (Hg0) in the NH and apply biogeochemical box modeling and chemical transport modeling to understand the trend drivers. Using linear mixed effects modeling of observational data from 51 stations, we find negative Hg0 trends in most NH regions, with an overall trend for 2005 to 2020 of −0.011 ± 0.006 ng m−3 y−1 (±2 SD). In contrast to existing emission inventories, our modeling analysis suggests that annual NH anthropogenic emissions must have declined by at least 140 Mg between the years 2005 and 2020 to be consistent with observed trends. Faster declines in 95th percentile Hg0 values than median values in Europe, North America, and East Asian measurement stations corroborate that the likely cause is a decline in nearby anthropogenic emissions rather than background legacy reemissions. Our results are relevant for evaluating the effectiveness of the Minamata Convention on Mercury, demonstrating that existing emission inventories are incompatible with the observed Hg0 declines.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1073/pnas.2401950121
UKCEH and CEH Sections/Science Areas:	Atmospheric Chemistry and Effects (Science Area 2017-)
ISSN:	0027-8424
Additional Information. Not used in RCUK Gateway to Research.:	Open Access paper - full text available via Official URL link.
Additional Keywords:	mercury trends, anthropogenic emissions, atmospheric observations, Minamata Convention on Mercury, chemistry-transport model
NORA Subject Terms:	Ecology and Environment Atmospheric Sciences
Related URLs:	Dataset
Date made live:	15 Oct 2024 15:25 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/538246

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1073/pnas.2401950121

UKCEH and CEH Sections/Science Areas:

Atmospheric Chemistry and Effects (Science Area 2017-)

ISSN:

0027-8424

Additional Information. Not used in RCUK Gateway to Research.:

Open Access paper - full text available via Official URL link.

Additional Keywords:

mercury trends, anthropogenic emissions, atmospheric observations, Minamata Convention on Mercury, chemistry-transport model