turning particle systems off

could i make an input to turn on particle emitters on then another to turn it off, thanks :D

If you just need to enable/disable specific ones, you can set the 'active' property on the gameobject containing them, or the 'emit' property on the particle emitter component of the game object.

var pe : ParticleEmitter;

  pe = GameObject.Find("myparticles").GetComponent(ParticleEmitter);

   if (Input.GetKeyDown("e"))
     pe.emit = false;

You can add all your particle emitters to a specific layer in Unity.

Then based on specific input in your update method, such as a specific key being pressed, you can simply disable all the particle emitters.