The larger particles are all I'm worried about. No need here for a hepa filter, the idea is to be able to work on my models without hocing up a lung. I have a ionizing filter and I doubt it would do a good job for very long because it is not designed to handle that much particulate matter. I have had the same furnace filter on my fan for over a year and it still works great, just vacuum it off every now and then.

Jason