Emit from Edge in Script

Hi there,

I'm trying to create an "area of effect" particle system that has the particles appear along the border of box shaped location.

Here is my code:

 // Set area of effect ring
         ParticleSystem particle = GameObject.Find("location").AddComponent<ParticleSystem>();
         ParticleSystem.MainModule main = particle.main;
         main.startSize = (float)0.5;
 
         ParticleSystem.EmissionModule emission = particle.emission;
         switch (location.size_identifier) {
             case 'S':
                 emission.rateOverTime = (float)25;
                 break;
             case 'M':
                 emission.rateOverTime = (float)50;
                 break;
             case 'L':
                 emission.rateOverTime = (float)100;
                 break;
         }
 
         particle.GetComponent<ParticleSystemRenderer>().material = new Material((Material)Resources.Load("Materials/Default-Particle"));
         particle.GetComponent<ParticleSystemRenderer>().sortingOrder = 1;
 
         ParticleSystem.ShapeModule box = particle.shape;
         box.shapeType = ParticleSystemShapeType.Box;
         box.enabled = true;
         // TRYING TO SET THE VALUE HERE
         box.box = new Vector3((float)(location.size * 1.28), (float)(((float)location.size) * 1.28), (float)(((float)location.size) * 1.28));

Everything works fine, I just need to know how to access the "Emit from:" value within the shape module and set it to "Edge" like I can do in the Unity editor. There doesn't seem to be a member variable for this and I'm having trouble finding any info for it online.