ParticleEmitter.emit

Description

Should particles be automatically emitted each frame?

function Start() {
	var emitter = GetComponent.<ParticleEmitter>();
	
	// Emit particles for 3 seconds...
	emitter.emit = true;
	yield WaitForSeconds(3);
	
	// ...then stop.
	emitter.emit = false;
}

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    IEnumerator Start() {
        ParticleEmitter emitter = GetComponent<ParticleEmitter>();
        emitter.emit = true;
        yield return new WaitForSeconds(3);
        emitter.emit = false;
    }
}