The air finally dried back out so I thought I would test out my particle counter.  I placed it behind my air filter fan, between the laser and fan, and on the far side of the laser cutter as a double check to make sure the smoke is not just clearing up near the fan.

You can see that between the laser and fan we have a very high particle count, plenty of smoke is generated.

On the far side of the fan things are much improved, not nearly as low as the base reading of 0-2 when not cutting, but more than 10x better.

And on the far side things are even better, the fan is definitely pulling the smoke towards itself rather than just cleaning the air around itself.  

Still in all cases things could be better.  When I produce enough smoke that you can see a steady trail it is clear that not all is being pulled into the fan.  A lot of the smoke is going down to the ground.  And there is still a smell of smoke in the air, although it does not linger for long. 

I'm sure a more focused collector near the laser cutter would help, and having an activated charcoal filter would be good as well.  It is something I need to spend more time playing with, but it is good that we are seeing numbers and some benefits of the filter I have on there now.