Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Idiopathic Pulmonary Fibrosis ?
    ### Response:
    Sometimes doctors can find out what is causing pulmonary fibrosis (lung scarring). For example, exposure to environmental pollutants and certain medicines can cause the disease.
                
Environmental pollutants include inorganic dust (silica and hard metal dusts) and organic dust (bacteria and animal proteins).
    