I have a honeywell air purifier...I got my info from consumer reports...I
also work in a hospital so I have an idea of what is necessary.
 
First, you HAVE to have a filter, in fact two or three different filters
are best.  The least you need is one with a HEPA filter..they last 1-3
years and are what hospitals use to filter their air.  This is about the
only way you'll actually get the smell out of the air, the odor molecules
are sucked into the filter, stick to it and clean air comes out.
 
Mine has 3 filters, there is a pre-filter around the hepa filter, it's
just a thin carbon sheet that encircles the filter to keep the HEPA
filter from pooping out too early...the HEPA's are expensive, so you
want to preserve their life.  Mine also has one called a CPZ filter, it
filters gases like carbon monoxide, cigarette smoke and other stuff...
anyhow.  I replace the prefilter every 3 months and the cpz every 6
months.
 
It is imperative that you get a real filter.  The ones from sharper image
with the metal blade/filters don't work AT ALL...consumer reports bashed
them because they had no measurable removal of particles from the air.
 
An added bonus is a purifier with ionizing affects... that also helps get
rid of odors.  One other thing you'll need to know when buying a filter
is they are sized by the room size they will clean.  You will need to get
one rated for AT LEAST the size of your room or even bigger if you can.
They're pretty much all somewhat noisy, but you get used to the sound.
 
If you want one that works spend the money...they really do improve the
air quality immensely.
 
good luck
HUGS
Angela
[Posted in FML issue 4254]