Go with the Trane Clean Effects. Obviously her health is important to you so you will set aside the time to regularly clean the thing, unlike most people. When it is clean it is the most efficient in the industry, the only problem is people who actually keep theirs clean are the minority. Also go with a variable speed blower and 2 stage condenser. This will keep the air moving over that filter for long periods of time, so you get more filtered air.
In addition, Trane claims their electronic one doesn't produce ozone.