Disclaimer: The GMOS Mercury Modelling Task Force (GMOS MMTF) is a scientific cooperative initiative aimed at the application of chemical transport models (CTMs) supplemented by comprehensive monitoring data for improvement of current understanding of the key mercury atmospheric processes and evaluation of present and future levels of mercury pollution. GMOS MMTF is organized on the base of GMOS project and with support of the UNEP Mercury Air Transport and Fate Research Partnership (UNEP F&T) and the Group on Earth Observation (GEO, Task HE-02-C1). Participation in the Task Force is open to all experts involved in model assessment of mercury fate and transport in the environment. The work of MMTF will be organised in the form of multi-model experiments aimed at answering particular scientific questions related to mercury atmospheric chemistry, speciation, anthropogenic and natural/secondary emissions etc. The simulation results will be evaluated against observations from the GMOS land-based network as well as measurement network of external partners, aircraft and ship-based measurements.