Mercury is a toxic pollutant that can travel long distances in the atmosphere before eventually depositing to the ground, where it can enter ecosystems and the food chain. A form of mercury called “reactive mercury” plays a key role in how much mercury ends up in the environment. However, measuring reactive mercury accurately is difficult. Current instruments often produce biased results, making it hard to understand long-term trends and to check if computer models used to predict mercury pollution are correct.

In this study, a new method was created to correct reactive mercury measurements. The method uses local environmental information, such as humidity and ozone concentrations, to adjust for known measurement errors. The correction was applied to 10 years of data collected at monitoring stations around the world. After adjustment, the data showed clearer patterns and matched computer models much better than before.

This corrected dataset provides a more reliable picture of reactive mercury in the atmosphere. It will help scientists and policymakers better understand mercury pollution and its sources. The study also highlights the need for more monitoring stations, especially in Europe and Asia, to improve global coverage and tracking of this pollutant.