A method and an apparatus are described for generating a concentrated aerosol. A first heated volume flow of pressurized gas a second volume flow of pre� heated dilution gas and a third volume flow of fluid are provided. After creating a droplet aerosol from a solution the aerosol solvent is quickly evaporated for creating a powder aerosol that then concentrated with a virtual impactor. The apparatus comprises a low flow resistance and achieves a high evaporation rate. The apparatus comprises a flow conditioner nozzle nozzle holder and a concentrator.