title: Defenses of the lung.
mesh_terms: D000397:Air Pollution; D006801:Humans; D008168:Lung / Q000276:immunology / Q000502:physiology*; D010587:Phagocytosis; D011650:Pulmonary Alveoli / Q000502:physiology; D012119:Respiration; D012141:Respiratory Tract Infections / Q000209:etiology