Atmospheric Mercury Data from the Italian Reti Speciali National Monitoring Network (2020–2023)

A comprehensive atmospheric mercury measurement dataset, spanning four years from 2020 to 2023, is introduced in this submission. This high-quality data was gathered by the recently established Italian Reti Speciali National Monitoring Network. The network was designed to deliver consistent, long-term environmental monitoring, specifically to meet the requirements of significant national and international accords, notably the Minamata Convention on Mercury. Consequently, this freely accessible dataset offers a vital baseline for characterizing atmospheric mercury concentrations throughout Italy. The acquisition methodology encompassed two main types of measurements across the monitoring stations. Firstly, automated equipment at three strategically positioned sites across the Italian territory recorded extensive time-series data for Total Gaseous Mercury (TGM) or Gaseous Elemental Mercury (GEM) concentrations. Secondly, a dedicated, specialized station within the network performed continuous, detailed speciation measurements, capturing Gaseous Oxidized Mercury (GOM) and Particulate-bound Mercury (PBM). The design, featuring broad geographical coverage and multi-component observations, is intended to enable a fine-grained analysis of mercury dynamics across various environmental contexts on the Italian peninsula. The final dataset is organized into quality-controlled files. These files contain the crucial Mercury Measurement Values alongside Associated Meteorological Data—such as wind speed, temperature, and relative humidity—which are essential for atmospheric modeling. This valuable public resource holds great significance for both the scientific community and governmental decision-makers. It serves to aid in the validation of atmospheric transport and deposition models and facilitates the regional and national evaluations necessary for measuring the success of emission reduction policies.