Abstract <p>The experimental and calculated results of the study of formation and growth of soot particles in a standard flat ethylene/air flame with the addition of dimethyl ether (DME) are presented. Two-dimensional laser-induced incandescence (2D-LII) was used as an experimental method to obtain data on the soot volume fraction in the flame. The time-resolved LII signal allowed us to obtain information on the mean size of soot particles depending on the height above burner (HAB). Kinetic modeling was carried out using a modern kinetic mechanism of pyrolysis and oxidation of hydrocarbons, including a sectional model of soot particle growth. DME additives have been shown to reduce soot volume fraction without significantly affecting final particle size. In addition, DME additives slow down the initial stages of soot particle formation but accelerate their subsequent growth.</p>