This paper presents an experimental study of aerosol/mist formed from emulsions of metalworking fluids (MWF) under laboratory conditions. Three different commercial MWFs were investigated at three different oil-in-water emulsion concentrations, I, 6, and 10% (v/v). The aerosol was generated by novel rotary aerosol generator at a constant rotating speed excluding heat generated by friction. In this way evaporation/condensation mechanism of aerosol generation was minimized. The emulsion was pumped at a constant flow rate. The aerosols characteristics were measured by an optical particle size analyzer. The data for particulate matter less than 2.5 mu m, (PM2.5), aerosol size distribution, Sauter mean diameter (SD), mass median diameter (MMD) and mass concentration are reported and discussed. Our data show that with increase of the oil concentration in the emulsion, the aerosol droplet sizes increase although the emulsions viscosity does not change significantly. (C) 2013 Elsevier Ltd. All rights reserved.