Instead of having a massive particle system that encompasses the whole level, you can make it just a bit larger than the camera view, and attach it to the camera. There is also a neat way to retain the parallax effect.
Setting the simulation space to “local” will make the particles follow you whilst the camera is following you. This is certainly not what we want. Setting it to “world” is better as the particles will not move relative to the camera, but the downside is no parallax effect. The solution is setting this to “custom”, and choosing the canopy (or any game object with the parallax script attached). The emitter will still follow the camera, but the particles will move in some negative direction to the camera to create the parallax effect.