The size of Respirable dust is -: (A) 1-5 microns, (B) 5-10 microns, (C) 15 microns, (D) 20 microns
Answer is A. - dust paicles smaller than 5 microns are directly inhaled into the lungs and are retained there. This fraction of dust is called respirable dust. - it is mainly responsible for pneumoconiosis. Reference : Park's textbook of preventive and social medicine, 23rd edition, pg no:805 <\p>