Experimental study of the influence of hydrogen as a fuel additive on the formation of soot precursors and particles in atmospheric laminar premixed flames of methane

•Impact of H2 is investigated in atmospheric sooting premixed methane flame.•H2 insignificantly modifies the maximum mole fraction of aliphatic species.•Hydrogen strongly influences aromatics and soot volume fractions.•Hydrogen has no effect on the aromatics enabling the inception of soot particles.