Hey, Which is More "Laggy", Emissives or Particle Systems?

The modeller on my team has suggested we use particle systems to make some of our lights “appear bright” with rays of the same color that just float or shoot out from around them,
while I believe we should just make the material the lights use an emissive to give them a glow effect.
What we’re wanting to know, is which one eats up performance more so we know which one not to use.
Appreciate your wisdom.