Atomization experimentals, motivated by the need to suppress misting of machining oils, were conducted on dilute solutions of polyisobutylene (PIE) in mineral oil using a coaxial air blast atomizer and an optical (Fraunhofer diffraction)) particle sizer. Polymer concentrations (0.1 to 1.0 kg/m(3)) and molecular weight (1.0 to 2.2 million) were varied to determine their effects on aerosol drop-size distributions. The pure oil and PIE - oil solutions were atomized at air/liquid mass ratios near 10 and atomizing air velocities of 150 - 270 m/s, producing droplet-size distributions with mass mean diameters (MMD) in the range of 7-15 mu m for the pore oil. Under identical atomization conditions, the MMDs of PIB solutions were 20 - 200% higher than pure oil. These observed increases in MMD correspond to significant reductions in the fraction of droplets falling below 5 mu m in diameter that constitute the misting problem in industrial machining applications. Observed effects of PIE on atomization are ascribed to the viscoelastic properties of PIE - oil solutions as characterized by the elongational viscosity eta(E) This relationship is examined by correlating the change in MMD caused by PIE additional with the stress-dependent elongational viscosity of PIE-oil solutions as predicted by the FENE-P dumbbell kinetic theory. The increase in MMD due to PIE varies linearly with the predicted eta(E), at constant atomization tensile stress.