150 reasons to celebrate - and to be careful
Rex Banks, Au.D., Doctor of Audiology
Director of Audiology
Canada is turning 150 years old this month! Such a momentous occasion usually brings celebrations full of food, music and good times. 150 is a big number for Canada, but can you guess what else is 150? The average firecracker explodes at about 150 decibels (dB) – with some as loud as 170 dB! At close range, 150 dB of sound is loud enough to rupture your eardrums and/or cause permanent hair cell damage in your inner ear. So, before you light that fuse, take a moment to learn how to safely enjoy fireworks on Canada’s birthday or any holiday.
How loud is too loud?
When evaluating whether a sound can cause hearing loss, there are always three things to consider:
- How loud is the sound?
- How close is the person to the sound source?
- How long was the person exposed to the sound?
We already know that a firecracker can ring in at at least 150 dB. The World Health Organization recommends that adults not be exposed to more than 140 dB of peak sound pressure level. For children, the recommendation is not to exceed 120 dB of exposure. Infants should not be exposed to firecrackers at all, since their ear canals are small which increases the sound pressure that hits their ear drums.
Loud sound from a firecracker is less likely to affect your hearing the further you are from the explosion. The recommended distance for adults is 15 to 20 metres away, while children should stand 50 to 60 metres away. A firecracker explosion is an impulse sound – so just a few seconds of 150 dB at close range can cause hearing loss.
You might be surprised to learn that explosions which occur hundreds of feet in the air at big fireworks shows can affect your hearing differently depending on the venue. For example, sound bounces off glass skyscrapers and other flat surfaces in a city environment. This reflected sound amplifies the noise that eventually reaches your ears. However, a fireworks show in a big open space - where the soundwaves don’t have anything to bounce off - results in weaker sounds ultimately reaching your ears. So, if you have a choice of fireworks venues, consider attending one at a park, beach or other large, open space.
Reducing noise impact with hearing protection
You should always wear some form of hearing protection when exposing your ears to fireworks. The two basic types of hearing protection are ear plugs and ear muffs. Both will have what’s called a Noise Reduction Rating (NRR). The highest-rated ear plugs have an NRR of 33 dB. This means that if the earplugs fit you perfectly, they would reduce the level of the sound going into your ear canals by 33 dB. Because most over-the-counter earplugs don’t fit your ears perfectly, they usually reduce sound by about half of the advertised NRR. For best results, see an audiologist at the Canadian Hearing Society to have custom-made ear plugs to ensure an optimal fit and maximum reduction of noise.
What to do after noise exposure
If you have been exposed to fireworks, you may experience tinnitus or ringing in the ears. You could also experience a slight, temporary decrease in your hearing that could last up to 24 hours. A permanent hearing loss is also possible. If you feel that your hearing may be been affected by fireworks, the “remove, reduce, rest” strategy is recommended:
- Immediately remove yourself from the noisy situation
- Reduce all sounds around you
- Give your ears some quiet time to rest so that they can recover
You should also contact us at CHS and see one of our audiologists for a hearing test. An audiologist can help you understand what could be happening to your hearing and determine if the hearing loss is likely temporary or permanent.
Fireworks are exciting, but it’s important to understand they can be dangerous to your hearing. However, with the right precautions, you can enjoy Canada’s 150th birthday safely and soundly.