Which of the following is false regarding repairable dust: March2010

Ans. D: Soluble dust remains in the lungs for a long time Respirable dust can enter respiratory system easily and can cause pneumoconiosis. Paiculate matter is generally sized as PM10 and PM5, the number indicating its size in microns. PM10 is inhaleable but is generally trapped in the upper lung/nose and can be expelled. PM5 is much finer and can travel deeply into the respiratory tract and lungs and is not expelled. They can be divided into two types: Insoluble-remains more or less in the lungs permanently Soluble-dissolve slowly, enter the systemic circulation and are eventually eliminated from the body Most common dust diseases are silicosis and anthracosis. Ans. D: Soluble dust remains in the lungs for a long time