I'm still trying to understand your reasoning as to why you would not want the ion switch left on? You evidently are already convinced the filter unit's ion switch does not corrupt the Geiger Counter performance (due to, for example, Electromagnetic Interference), and it does improve the performance of the filtering unit (which is to collect more 'stuff', radioactive or not, from the air), so why would you not want it on?

It is located on the first floor of my home, not the basement. I will leave ionization switch "OFF" until that debate get's settled

The manual for this unit says the hepa filter is good for about 4 months. For this application usage, is that statement still true?

Yes, I would throw it away after 4 months but I would not leave the filter in for 4 months straight. You can take it out and make sure all the radioactive readings decay away back to normal background levels (this means it was likely mostly radon) before you bang it on the front step set it aside to be used again. Of course do not inhale this dust/particles. Remember that when you replace the filter, it will take hours before the filter returns to the same level the previous filter was at.

I suggest only attempting to replace your filter during times when your readings are in your stations normal levels. If your readings are high, I suggest not touching it! You wouldn't want to screw up a trend pattern that you could be collecting like my stations pattern vs. the Seattle WA. EPA gamma graph.

I'm wondering if some of what is assumed to be radon is instead noble gases? If so, is it possible then that some of the eventual reduction in measurements off a filter are due to the gasses (at sub-micron size particulate level) being slowly exasperated from the filter material? Maybe this phenomena explains some of these spurious 'radon progeny' assumptions that don't seem to decay away in their expected time frames.

I believe it is not fair to say 100% one way or another what it is other than it is radioactive and I consider it all bad.

I think radon is attributed as the second leading cause of lung cancer, after smoking. But I'm curious if this issue is clouded by the additional release of noble gases from the nuke industry. If indeed the so-called 'cancer factory' nuke plants are releasing tremendous quantities of ionized noble gases, what effect does that have on the ozone, and thus potentially, to 'global warming'/'climate change'?

Maybe some of the radon test kits, where you collect samples and send them off to a lab would answer those questions. It might be worth a call to the lab in advance to see if their tests would be useful. I have no experience here, but there seem to be kits which include the lab fee for $10 - $15.

I agree John! In fact, during hurricane Sandy many of the East Coast nuclear plants had to SCRAM "EMERGENCY SHUTDOWN" and as I watched (wind map link below) the hurricane winds over the next couple days reach me in Illinois, I seen my inside pancake geiger counters background level average increase. I only wish I had my outside unit then!

http://hint.fm/wind/

I would save your money and just buy a Safety Siren radon only detector like I own. I own two of them. Your radon levels change due to weather and season. Those cheap little charcoal can tests are not worth your time or money.

http://www.amazon.com/Safety-Siren-Series3-Radon-Detector/dp/B000CEAY64/ref=sr_1_1?ie=UTF8&qid=1389203501&sr=8-1&keywords=safety+siren