My Husband has COPD We live in Alaska and with Mt. Redoubt erupting.It really been hard on him lately An October 2008 report by the Department of Environmental Health at the Harvard School of Public Health reports that people with COPD "have substantial mortality risks associated with exposure to particles." According to the study, particles may impair ventilation in COPD patients by causing airway narrowing and increasing the work of breathing. So while air purifiers are certainly not a cure for COPD, they can provide cleaner air, which according to the Harvard study, is paramount to people with COPD. And after doing research The Honeywell HEPA captures 99.97 percent of pollutants from the air. So We ordered one at first we thought it would be a problem to install. We Were Wrong. IT WAS SO EASY TO INSTALL We do not have a forced air system But the Honeywell Whole-House HEPA Air Cleaner Also can stand alone. So we just independently ducted it. Also to replace the filters there is a Indicator to let you know when it needs to be done. I would highly recommend The Honeywell to ANYONE.