Will tar in lungs disappear over time?

Vitamin A: Take vitamin a to keep your lungs healthy. Two studies involving mice, "vitamin a deficiency injures lung and liver parenchyma and impairs function of rat type ii pneumocytes" and "retinoids have differing efficacies on alveolar regeneration in a dexamethasone-treated mouse, " show that cigarette smoke depleted the lungs of vitamin a and that the lungs' air sacks healed once given vitamin a.