I have Ionic breeze machines in the master bedroom and DD's room. And in the bathroom that houses the cat's litter box, I use a filter that plugs into an outlet and has charcoal filtering. I got it at Target and it is called TrueAire. It really keeps the kitty odor away! The ionic breezes really trap a lot of dust, etc, and I felt like they really helped a lot last winter during flu season to help us breathe well while sleeping.

andry: You might want to read this article on filtration. Be careful about your choices. There is a lot of confusion on air cleaning and the usefulness of it.....in some cases a waste of money. Use this link: http://www.epa.gov/iaq/pdfs/residential_air_cleaners.pdf and this one: http://www.epa.gov/iaq/pubs/airclean.html This post was edited by audiomixer on Fri, Feb 8, 13 at 0:42

I have an earlier model of the one in the link below. Bought it in 2002, and just before they were discontinued I bought 6 filters. Since I am only on the second filter since this year, I am covered for a while, if the unit doesn't peter out on me. I got mine because of allergies. It lives in my bedroom. I only turn it on at night, and only during allergy seasons. Allergy seasons are twice a year for me. February because of cedar tree pollen and September till a killing frost because of ragweed. I have other allergies, but those two triggers are the WORST for me. Moni Here is a link that might be useful: honeywell air cleaner

Update: Today the building owner brought in a air-duct cleaning person to take a look and prepare an estimate. I didn't make a great first impression. I didn't know it was the owner. When they came in, I made a face and said I thought we were going to do testing first and that I wanted new ducts rather than duct cleaning that makes a mess. The owner retorted "i've been doing this for 50 years...I have many buildings. I know what I'm doing...". Jeez. Building owner does not make an HVAC expert. And not updating a 30-year old system and letting the building get to this state doesn't speak to his landlord credentials! Although, I do commend the responsivness and willingness to fix the problem. I tried to make nice when I figured out who he was. I had told my boss earlier air-duct cleaning was the last thing I wanted after stories I read about it making a mess of the office, but I guess he didn't mention it to the owner as I requested. So the 4 of us (owner, boss, me, airduct rep) had in depth conversation about the issues. The airduct cleaning guy said it is very rare to find mold in this type of scenario but they do look for it and will clean it if it is minor or stop and report it otherwise. When I told him I had read multiple stories about office air-duct cleaning leaving a mess behind, he replied that those companies failed at their job. He assured us there is no mess or disturbance left behind. He described the process in detail, but I zoned out in the tech talk. I didn't hear that they cover or clean all surfaces. They claim the technique cannot generate extra dirt. hmmppph. We talked about air-quality testing (which he does not do), and they were unclear if it would serve a purpose. To me, test then treat seems to be the natural order. One would want to know the particulate count b4 and after cleaning, right? I surely do. It is still up in the air what we will do. My boss said maybe he will pay for the testing if the owner won't. He seemed to agree with me that testing first was the right thing to do, but yet he still seems inclined to use dust on surfaces as a metric. I said its the stuff you can't see that the testing is for. Is it? I don't really know. Meanwhile, I bought an air purifier for my bedroom. Its on order. I can't wait to see if I wake up less congested. Meanwhile, the heater hasn't kicked on much or maybe at all this week. I stopped taking my inhaler last week to see if coughing came back this week. The temps have picked up a bit and we get a lot of afternoon solar heating. I almost wanted to put the A/C on today it was so warm. So it might be difficult to assess anything once heating season dies down.