PRESTATION : Stack emissions proficiency testing scheme In the field of stationary-sources emissions, Ineris organises Inter-Laboratory Comparisons (ILC) on a test bench and analytical proficiency testings (PT). Analytical testings ILCs on the test bench are addressed to sampler laboratories and relate to standard reference methods that must be applied to control atmospheric emissions from classified facilities. These are either "automatic methods" implemented using specific gas analyzers, or "manual methods" including a sampling phase on suitable media and an analysis of these media, by an analysis laboratory. Analytical ILCs are aimed at analytical laboratories and focus on the implementation of the analytical part of manual reference methods. Samples doped in real matrices are sent to participants for analysis. This cross-laboratory comparison allows laboratories with accreditation to be able to meet the requirement to prove their competence.