This relates to the abovementioned Playground code.
There is no leakage if you use the source code properly - https://playground.babylonjs.com/#X37LS1#86
(there was some in the past but it is corrected for some time now - Fix memory leak for particle sub emitter Ā· BabylonJS/Babylon.js@1c97c9a Ā· GitHub )
Let me make it clear.
This function create a ParticleSystemSet, and then dispose it.
But the disposing canāt work properly, since after disposing, 2 ParticleSystem stay in the Scene.
This is because nested subEmitters havenāt been dispose correctly.
function Firework(position)
{
// Create default particle systems
var parentSystem = BABYLON.ParticleHelper.CreateDefault(position, 1);
// Sub emitters
function createFireworkSubEmitter(color, name) {
var particleSystem1 = new BABYLON.ParticleSystem(name, 2000, scene);
particleSystem1.particleTexture = new BABYLON.Texture("https://minio.cnbabylon.com/public/Assets/Flare.png", scene);
particleSystem1.subEmitters = [[ createFireSubEmitter()],
[createFireSubEmitter()]];
var se = new BABYLON.SubEmitter(particleSystem1)
return se;
}
function createFireSubEmitter() {
var fireSubEmitter = new BABYLON.SubEmitter(new BABYLON.ParticleHelper.CreateDefault(position,200));
fireSubEmitter.particleTexture = new BABYLON.Texture("https://minio.cnbabylon.com/public/Assets/Flare.png", scene);
return fireSubEmitter;
}
parentSystem.subEmitters =[[createFireSubEmitter(new BABYLON.Color4(1, 0, 0), 0.4, 0.6, 2.4, 1), createFireworkSubEmitter(new BABYLON.Color4(0, 1, 0, 1.0), "first")]]; //blendMode and the order subEmitters will effect the result
parentSystem.start()
parentSystem.dispose()
}
So as far as I understand your question is how to dispose subemitters with parent system, am I correct?
As you see, both subemitters are not disposed and leave in the scene a transform node and a particle system.
Thatās right.
Seems that particleSystem1 is just not disposed.
Hereās a little PR to fix this issue by making sure that the internal array _subEmitters has been created and populated when disposing. 
You rock!