Wht causes haziness on a chest x-ray?

Ah, "haziness".....: Anything that increases density--which in lungs would usually be fluid or infection--either pulmonary edema (excess fluid in the lungs) or infection (like pneumonia).

Many things: General term is haziness. Volume loss, pneumonia, contusion, scarring and fibrosis, interstitial disease are possibilities. Clinical information, physical exam, and results of other tests have to be correlated.