Exposure to noise above-causes permanent hearing loss -

Sound in dB Effect 20 Whispering 40 Quiet library 60 Normal conversation 70 heavy street traffic 80 printing press 85 Recommended maximum 110 Train passing through station 120 Motor car horn 140 Threshold of pain 150-160 Mechanical damage Park's Textbook of Preventive and Social Medicine, 22nd edition, Page No. 688