Using AI denoiser on render passes

Hi,
I’m a total noob in Blender and I have a question regarding the render passes. Is it possible to make denoiser work for passes (not only final image)? I have a Volume.direct pass that I want to add 2 times on top of my composite to make the atmosphere more dense, but the layer is full of noise. I compose in AE using extractor. This is not a static frame but animation, so I need the solution that works for multiple frames.

What result do you get when you plug the volume pass directly into the denoise node? Could you perhaps composite the frames, then use the denoise of the composite image afterwards? If the volume pass is for something like atmosphere, you could also consider denoising it with a simple blur filter!