Every source with sufficient energy to trigger combustion, i.e. hot surfaces, flames, smouldering pockets, mechanically generated sparks, electrical equipmentAll objects serving the application of electrical energy, either as a whole or in part., electrostatic discharge causing clouds of dustSmall solid particles in the atmosphere, which settle due to their own weight, however, can stay airborne in the atmosphere for some time as a dust/air mixture. or dusts deposits to ignite.
