A new international study, led by The Cyprus Institute’s Climate and Atmosphere Research Center (CARE-C) and published in Nature Communications, provides the first direct molecular-level observations of oxidized mercury species in the atmosphere, challenging long-standing assumptions used in global models. Mercury is a persistent environmental pollutant with serious implications for ecosystems and human health, making its molecular study crucial for accurate environmental assessments.

 

In the study, researchers report direct in-situ observations of oxidized mercury compounds in polar air, including halogen-containing species such as mercury bromide, chloride, and iodide. These observations were achieved using advanced atmospheric pressure chemical ionization mass spectrometry (CI-APi-TOF), combined with ambient ion composition analysis.

 

A key finding of the study is that mercury dibromide (HgBr₂) dominates oxidized mercury speciation in polar regions. This result contradicts widely used atmospheric models, which have assumed different dominant mercury species and reaction pathways. The findings indicate that important chemical processes are currently missing or misrepresented in these models. By providing real-time molecular-level measurements of oxidized mercury in the atmosphere, the study establishes a stronger observational foundation for understanding mercury cycling in the atmosphere. This improved understanding is critical for accurately predicting where mercury deposits and how it impacts sensitive ecosystems. It also bears particular importance in polar regions, as deposited mercury can then enter marine food webs, posing risks to Arctic communities that rely on seafood.

 

According to the study’s lead author, CARE-C Associate Professor Tuija Jokinen: “This approach opens new possibilities for studying mercury chemistry beyond polar regions. Applying these methods to urban, marine, and volcanic environments and reanalyzing existing datasets could significantly refine our understanding of global mercury transport and transformation. Ultimately, these advances support more accurate environmental assessments and strengthen efforts to protect ecosystems and human health from mercury pollution.”

 

The work was carried out as part of the European Research Council (ERC) Starting Grant project BAE.

 

Reference: Jokinen, T., Gómez Martín, J.C., Feinberg, A. et al. Direct observations of atmospheric oxidized mercury speciation in polar areas. Nat Commun 17, 3160 (2026). https://doi.org/10.1038/s41467-026-71146-z