I found these articles to be interesting, possibly useful:

http://scienceblogs.com/effectmeasure/2006/11/how_does_flu_spread.php

http://scienceblogs.com/effectmeasure/2009/03/flu_virus_in_the_air_of_an_eme.php

http://scienceblogs.com/effectmeasure/2009/09/flu_handwashing_and_disinfecti.php

Interesting how much we know. What we think we know based on logical inference. What we are guessing at but assume based on a lack of other options.

They were interesting but a bit technical for me.
I think they say you should cover your mouth when you cough, and that UV light helps, so try to get out in the sun more .

As one of those people with a "compromised immune system" I found the articles very interesting. Thanks for taking the time to post the links!