Like Tater said, for distance you don't need to use a Proximty block, there is a Proximity field directly on the Particle Emitter block.
For Field of View, I considered adding this in 2.5 but decided against it because it caused popping to the point it wasn't useful.
i.e. The particles only start emitting once the emit position is in view, so what happens is you can see them start to emit (they pop in), then you look away, they stop, then you look back, they start again. This causes popping. And in the case of say a smoke stack, it leaves holes in the stack. The immersion was constantly being broken.