Social & Preventive Medicine Size range of dust, which is regarded as health hazard: September 2011 A 0.1 to 0.3 microns B 0.3 to 0.5 microns C 0.5 to 3 microns D 3 to 5 microns 💡 Explanation Size range of dust, which is regarded as health hazard: September 2011 ✓ Correct Answer: C. 0.5 to 3 microns