In partnership with the environment and space physics and chemistry laboratory at orleans and CNES (National Space Research Centre), we have started the development ofa ‘LOAC’ measurement system, that will count and size grade aerosols, for balloon-carried stratospheric measurement applications. The first flight of the LOAC was organised by the CNES, from the ESRANGE/Kiruna base (Northern Sweden), on 1st April 2011. Values were measured between ground level and an altitude of 25 km. an analysis of the data obtained has already confirmed that liquid aerosols and solid particles can be detected, together with droplets and crystals in the clouds, with particle sizes between 0.5 and 40 μm. this first flight also confirmed the presence of solid particles of a few μm in the stratosphere, at an altitude of around 20 km. Further tests will be conducted to enhance both scientific knowledge and the performance of the new measuring instrument.