Reduction of both atomizing steam and particulate emissions were investigated in a 350 MWe utility boiler. A residual fuel oil was dispersed as a fine mist into the furnace with sixteen atomizers of internal turbulent chamber type. The existing atomizers were replaced by Y-jet type atomizers. To do this, full scale prototypes were designed and tested in a cold model rig using mineral oil as the fuel and compressed air as the atomizing medium. The oil droplet size distribution was measured from a single port of each prototype by using a Malvern particle sizer. The prototype to be tested in the power station was selected based on the smallest oil droplets produced along with lower compressed air consumption. In the power station, the burners were modified to install the new design of Y-jet atomizers. Field tests were conducted at 50, 75 and 100% load. Atomizing steam was measured, as well as particulate emissions and the furnace exist flue gas temperature. With the Y-jet atomizers, the atomizing steam was reduced 55% with respect to the original atomizers; the unburned carbon particles were reduced by a maximum of 50%, the furnace exit gas temperature was similar between the two type of atomizers and no side effects were observed in the boiler.