We report a novel technique to generate steady capillary microjets with diameters in the range of micrometric size. The microjet is driven by the aerodynamic suction of a highly accelerated coflowing gas stream. After undergoing capillary instability and breakup, these jets eventually yield remarkably monodispersed size aerosols in the micrometric range. Aerosol generators of this kind may have a wide range of applications in science and technology.