Former New York City Mayor Rudolph Giuliani is breathing on his own after being hospitalized with pneumonia and placed on a ventilator. Giuliani's spokesperson said Monday that the 81-year-old remains in critical but stable condition at a Florida hospital and is being monitored as a precautionary measure. Spokesperson Ted Goodman said Giuliani’s condition was exacerbated by restrictive airway disease attributed to his exposure to dust and toxins from the Sept. 11, 2001, attack on the World Trade Center. Giuliani’s hospitalization, near Palm Beach, Florida, came after he was heard coughing Friday on his nightly online talk show and hoarsely told viewers that his voice was “a little under the weather.”