This project is the demonstrative phase of the larger Aerolab project which is fully in line with the objectives of monitoring atmospheric emissions (GHG, NH3, aerosols...) – in particular, in support of low-carbon technologies, public policies to reduce GHGs on cities/metropolies, carbon storage and waste management and water sanitation – and which aims to position the Grand Est region as an essential leader in anthropogenic emissions issues at national, European and international level. This demonstrator concerns the monitoring of GHGs on the city of Reims and on methanisers in the Grand Est region. The network of observations necessary to monitor the emissions of the city of Reims will be sized. In particular, a first experimental network of fixed sensors will be deployed in and around the city. Estimates of the atmospheric plume made during airborne campaigns will make it possible to understand the extent of emissions and the emission rate on the city of Reims. Thanks to URCA’s ROMEO supercomputer, the city’s emissions can be defined in the space at a finer scale. Therefore, the quantification of GHG emissions from LNG plants will be carried out for the first time. Measurements of these emissions will be carried out using sensors developed at the URCA.