Course announcement: 15th School on Atmospheric Aerosol Physics, Measurement, and Sampling will take place in Hyytiälä Forestry Field Station in Juupajoki, Southern Finland, from May 17th to 24th, 2019. This summer school is mainly intended for doctoral students (5 etc), young scientist, and personnel from aerosol measuring stations and research institutes, involved in ACTRIS, CRAICC, GAW, GUAN, and EMEP, but also from national metrology institutions involved in EMPIR projects. The lectures will be given and discussed interactively in English. The applications for the course should be done electronically using the following link: https://elomake.helsinki.fi/lomakkeet/94500/lomake.html. For further information on the course contents, travel and accommodation, please see the course announcement or contact: katrianne.lehtipalo (at) helsinki.fi and juha.kangasluoma (at) helsinki.fi. Dated 4 March 2019.