Institute for Nuclear Research (ATOMKI) will contribute to collecting flask samples at Hegyhátsál (collaborationwith GUF) in WP 3, house a mobile GC-IRMS facility for measurement of methane isotopologues in WP 4, and willwork with MO and EMPA in developing inverse modelling capability for F-gas and CH4 emissions. ATOMKIbelongs to the Eötvös Loránd Research Network (ELKH) of Hungary. Researchers from two main sections ofATOMKI (Isotope Climatology and Environmental Research Centre [ICER] and International Radiocarbon AMSCompetence and Training Centre [INTERACT]) will be involved in PARIS. The infrastructure of the involvedgroups covers a wide range of trace gas/GHG analyses (several Picarro and Los Gatos CRDS spectrometers), stableisotope mass spectrometers (Thermo IRMSs for δD, δ13C, δ15N, δ18O, δ34S) and radiocarbon accelerator massspectrometer (EnvironMICADAS AMS). ATOMKI will also provide access to the Hegyhátsál tall-tower greenhousegas monitoring station (HUN), which becomes a Class 2 monitoring site of the ICOS atmospheric network in 2022.