The lungs are the organs used for breathing. They are responsible for bringing oxygen from the atmosphere into the body through a series of branching air tubes and exchanging it for CO₂. The CO₂ is then released back into the atmosphere. The lungs are constantly exposed to danger from the dusts that are breathed in. Luckily, the lungs have another function; they have a defense mechanism that protects them by removing dust particles from the respiratory system. Even though the lungs can clear themselves, excessive inhalation of dust may result in disease.