I have worked in electronics manufacturing all my life, where ESD is a real problem. I have trained 100's of people in the problem, but I never really considered it an issue in the Workshop.
My first though is that the dust density in the workshop is no where near enough for air ignition. With dust extraction running it will be even lower.
I use a blow torch for decorating with no fires (yet!), so a spark from ESD is even less likley.
The science bit...
The trick with ESD is to elimiante disimilar materials from rubbing / pulling apart from each other. By disimilar I mean in terms of the Triboelectric series.
http://www.trifield.com/content/tribo-electric-series/The further away the two materials are on this scale the more likely the risk of spark. (Rabbit fur in non stick frying pans = not good !)
High velocity air streams are also a problem, as the air is "moving" over the internal surface of the PVC pipe it gathers charge. Luckily dust and fume extraction systems are very low (relativly speaking) velocity. The charge in the air discharges as it exits the tube, so if you really want a belt and braces approach, wrap so tin foil around the end of the pipe and run a wire to the closest grounded surface (pipes, bolted down lathes etc). Or you could disassemble a plug top and just use the earth pin.
Frankly I think we have more important stuff to worry about.