All combustion engines emit a wide range of toxic emissions. On one hand, the gaseous fraction contains mostly nitrous gases (NOx), carbon monoxide, hydrocarbons and sulfur dioxide. Thanks to ICAO regulations, NOx emissions have substantially decreased in recent years, especially by optimizing the combustion process. On the other hand, characteristics of the non-volatile particulate matter fraction (nvPM) changed significantly, as the mean aerodynamic diameter decreased from large fractions (1-10 µm) to an ultrafine fraction (< 100 nm). The currently established measurement principles, regulated in ICAO Annex 16, Volume 2, are therefore becoming more and more useless when measuring nvPM. To this end, the Swiss Mobile Aircraft Engine Emissions Measurement System SMARTEMIS, a new, robust, industrial-grade nvPM and gaseous emission measurement system has been developed jointly between Empa and FOCA. SMARTEMIS can quantify nvPM emissions to a hitherto hardly reached degree. This made it possible to define a new nvPM certification standard, which will come into action for all turbofan engines with thrust > 26.7 kN from 2020 on. Yet, smaller turbofan, all turboprop and all turboshaft engines still lack any stricter regulation. Moreover, the exhaust characteristics of such engines is still largely unknown. As well, the detrimental effects of engine deterioration onto exhaust composition has not yet been quantified.AGEAIR I and II wants to address these two problems: During the project AGEAIR I (06/2016-03/2020), SMARTEMIS will be used to gather first data quantifying the engine deterioration effects of large turbofan engines (> 26.7 kN thrust) on pollutant emissions. This measured data will be used to develop a first version of an engine deterioration model predicting changes in the engine exhaust. During AGEAIR II (01/2020-12/2022), we will validate the model with further measurements and start assessing the exhaust gas composition of turboprop and turboshaft engines of small to medium-sized helicopter and turboprop planes. The findings will i) complement engine emission datasets to generate a comprehensive aviation emission inventory, ii) generate a base of discussion for future regulatory actions for small turbine engine emissions and iii) help understanding the combustion processes of small turbine engines