Mercury (Hg) is a toxic element with adverse effects on humans and wildlife. Cross-border export of atmospheric Hg emissions makes Hg a global pollutant. In 2013 the UNEP Minamata Convention on Mercury was signed by over 100 countries and aims to reduce future Hg emissions. Implementation of environmental Hg policy requires environmental monitoring efforts. Hg monitoring networks such as GMOS and AMNet typically gather data on atmospheric Hg concentrations, but do not provide information on the Hg emission source. In the ERC StG MERCURY ISOTOPES we have developed dual Hg isotope signatures as fingerprints for Hg sources and transformations. Our observations suggest that most, but not all, anthropogenic Hg emission sources are isotopically distinguishable. The goal of the ERC POC MIMO project is to develop, together with Tekran Inc., the largest global Hg instrument developer, a commercial Mercury Isotope MOnitor (MIMO) that is compatible with current Hg monitoring equipement and programs. Successful development of the MIMO will generate (a) patent(s), drive sales of MIMO and consumables, opens up worldwide opportunities for environmental monitoring companies, and addresses a globally important societal issue.