Near-global mapping of TGM based on aircraft measurements from intercontinental flights*

Atmospheric mercury sources are numerous and complex. Accessing and understanding the strength of each source is important for understanding mercury cycling between the various environmental compartments as it affects atmospheric loadings.In this regard, this study presents an upper tropospheric near-global source evaluation of total gaseous mercury (TGM) and its impacts on atmospheric loadings are therefore examined using TGM measurements from a container aboard intercontinental passenger flights between 2005 and 2016. The trove of measurements performed on board of IAGOS-CARIBIC was exploited through developed receptor models, assuring a high likelihood of extracting the maximal amount of information from the collected data. We reconstructed atmospheric mercury concentrations and assessed the contribution of the major natural and anthropogenic sources, explaining 98% of the observations with a correlation of 82% and a significance level of 0.001 (p-value).The results show that Asia stands out as the main hotspot of TGM, mainly loaded by factors linked to industrial and SO2-related sources. Contribution and geolocation strength of industrial, volcanic, biogenic, biomass burning, and petrogenic-related sources were quantified, identified and presented.The improved data analysis tools as probability mass factorization methods provide additional insights into the nature of the mercury source that can then guide the development of more effective mercury-related management strategies.

Automated summary

This study presents a near-global evaluation of atmospheric mercury sources and their impacts on the atmospheric loadings. The results show that Asia is the main hotspot for total gaseous mercury (TGM), mainly loaded by industrial and SO2-related factors. The improved data analysis tools provide additional insights into the nature of the mercury source, guiding the development of more effective management strategies.