The condition can be fatal if left untreated, but the tetanus vaccine and improvements in treatment mean deaths from tetanus are now very rare in the UK. In 2013, there were only seven recorded cases of tetanus in England and Wales, and no deaths.
Sound pressure is measured in decibels (dB). Like a temperature scale, the decibel scale goes below zero. The average person can hear sounds down to about 0 dB, the level of rustling leaves. Some people with very good hearing can hear sounds down to -15 dB. If a sound reaches 85 dB or stronger, it can cause permanent damage to your hearing. The amount of time you listen to a sound affects how much damage it will cause.
The noise level measures an average of 99 dB. You are wearing ear protection with an SNR of 19. Thus, the acoustic pressure on your ears is on average 99 â 19 = 80 dB. The higher the SNR, the higher the level of noise attenuation provided by the hearing protection.