[SteveFord]

I work in a giant office building where the windows haven't been opened in decades.
More crap rains down on me from the ventilation system than you can believe.
The entire floor smells like a used vacuum cleaner bag.
It's pretty much a given that I'll be having sinus surgery next month.
I can not count on the employer to do very much in the way of improving the air quality.
Can anyone recommend a desktop air purifier that can help keep this crud down to a minimum?

[Elizabeth]

Well, it depends on if you have to be able to make and get telephone calls.
Most good air cleaners make enough noise that a desktop would be out of the question if you really need to  concentrat when talking on the phone.
It is suprising how that little extra noise just creates havoc.
Anyway, go for a floor model. One you can leave on all night under your desk (if possible)
Generally a HEPA design is best.
I own two Honeywell round canister types. I leave one on in my bedroom during the day.
It really cleans out the air, (which moves around more than one  thinks) So my whole apt is cleaned out with just the one in the bedroom running part time.

[SteveFord]

I have two Honeywell units at home but they may be too loud for an office environment which is really saying something as my coworkers can really put out the decibels.

[ptmconsulting]

I picked up a unit for my office desk from Target. Cost about $50. It worked great for the first 2 months, when we moved into our new building and there was just too much new construction dust everywhere. It had a little ultraviolet bulb inside as well as n HEPA air filter.

But then it started making noise - the death rattle. I really don't use it much anymore but it did what it needed to do for those 2 months when I needed it.

[FullRangeMan]

The best filters are those work on Ozone, O3 is a near miraculous gas that kill over 200 bacteria and micro organisms and for this the public is non informed by the great media.

Water filter with ozone generator also is great.
[bhttp://www.amazon.com/Machine-Purifier-Generator-Alpine-Cleaner/dp/B001L4GNLE/ref=sr_1_1?s=home-garden&ie=UTF8&qid=1367335751&sr=1-1&keywords=ozone+air+filter[/b]