Funny you should ask - I do have advanced degrees in Mathematics and Physics.
Ion generation has been around since the beginning of time. Anytime a charge is applied/removed to/from a particle (atom, molecule) - you effectively create an "ion" - a result of having lost or gained one or more electrons.
This has been part of the recent "techno/buzz word" revolution where if it sounds impressive - it must really work. Ion generation has been applied to cleaning the air, improving moods, increasing performance of automobiles. About the same level as those magnets that people snap onto their fuel line to "break apart the molecules and promote a more efficient combustion".
While the principle idea (Physics) behind these devices are sound - the application is far from being anything revolutionary. Except for the amount of revenue they generate. They boast scientific research behind them - but look up the references, they are either bogus, or clinical trials - too many uncontrolled variables to be considered a valid, scientifically.
Anything that you place inside the intake will reduce overall air flow. No amount of ions will help overcome that. Keep in mind that most ion generation - charged plates, coils, rods, etc - there is a chance of ozone being produced. We all know what ozone will do to most components.
Doesn't mean that ion technology isn't viable - just not for this type of application.