What will cause a pulmonary embolism besides surgery?

Pulmonary embolism: Has also be associated with extended travel (sitting in a car, airplane, train, etc), hospitalization or prolonged bed rest, smoking, birth control pills, cancer, pregnancy, genetic predisposition most commonly factor v leiden deficiency, protein c or protein s deficiencies and Antithrombin iii deficiency.

Immobility: Prolonged immobility i.e. Air travel or other can cause thrombosis and then embolization to the lungs.

Many other things: Genetic predisposition, autoimmune diseases such as lupus, cancer, smoking, birth-control pills to name a few.