Its Portable Air Conditioner Season right? Well spring is also Air Purifier Time
I will keep it simple. DONT buy just an ionizer. Honestly they are usually worthless for removing particulates (small things in the air that bother us). Now some HEPA air purifiers have option ionizers and thats fine but just make sure you get a HEPA filter. The Airsopure MS-980 is the best model that i know of as it uses a multilevel process.
A HEPA air puifier can usually only clean smaller areas like the bedroom but at least it will clean that area compared to the promises of ionizers cleaning your whole house
So save a few $ on your portable air conditioner purchase so you have enough to get a good HEPA air purifier also, it will last you for years and energy use is usually pretty limited