Asthma experts no longer recommend moving to another location to control your asthma, as new medicines work wonders for controlling asthma.  Ideally you should be able to work with your physician to determine what you are allergic (or what she's allergic to), and then her physician will have an appropriate recommendation.  Obviously, if you know what you're allergic to and can avoid it, then do it.  But, otherwise, there are some options.  One is allergy shots.  Another is asthma controller medicines such as Advair or Symbicort.  Another great medicine for asthma and allergies is Singulair.  I personally am taking Advair and it works wonders to control my asthma.  And Singulair is actually the first medicine to really control my allergies.  Yet, your daughter will want to work with her asthma doctor to determine which therapy regimine works best for her.  The same for her children. 

Sorry for the late response.  I hope this is still useful to you and your duaghter.