Particle sprites is often needed in production because it's fast, with a good amount of details. But an awkward problem occurs that hard edges intersecting with objects appear when they need to react with the scenes. The illusion of volumetric effect breaks as it's easy for anyone to realize that they're just flat patches.
I developed a method which could soften the intersection edges, works well in most scenes, but a little bit hard to set up. Basically the way it works is by moving all vertices along the normal direction by a length which is driven by a high frequency sin function fed into frame numbers. Then when in render time, some amount of space wrapped around the objects is hold out with the contribution of motion blur, so to say, the softened edge done.