There are actually no volume lighting effects in those promo renders. It's all based on z-depth, not volume.

You can get fast z-depth "fog" effects in Poser using the Depth Cue feature in the Atmosphere node. It's much quicker than Volume.

Edit: there is also a Python script that will output a z-depth mask. I can't recall who wrote it.

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)