As an audiologist in Nashville, I work with patients with hearing loss every day. With each new patient, I begin our conversation with a series of questions about his or her hearing history. I want to know about family history, ear disease, medications and of course, noise exposure. Noise-induced hearing loss is one of the leading causes of permanent hearing loss among my patients. While some sources of potentially detrimental noise levels are obvious, like shooting, loud music and machinery, others are a bit more insidious.
Noise Induced Hearing Loss
Let’s talk briefly about noise-induced hearing loss. Hearing damage due to loud noise is about exposure. Exposure is a term that combines how loud a sound is multiplied by how long a person’s ears are exposed to the sound. Exposure is what determines how potentially-detrimental a noise can be to hearing. The chart below is taken from the Occupational Safety and Health Administration.
This table shows that a level of 90-dBA is permissible for up to eight hours per day. However, as the noise level increases, the amount of time an individual is allowed to be exposed without hearing protection decreases significantly. There are some levels (115-dBA and above), that any degree of exposure is not permissible. That is because sounds this loud can cause damage even in very short durations. As a reference, this chart from noisehelp.com shows average levels for loud sounds we might encounter:
Here is a practical example that many of us may have experienced as child: you and friend are lighting fire-crackers. If you light a firecracker and stand back 10 feet, the level is probably pretty safe for your hearing- let’s say 85-dB. If your friend lights one five feet from you, the distance is half, so the sound level is four times more intense.
Without going into too much detail on decibel mathematics, this results in a new level of 97-dB at your ear. But, what if, you are lighting a fire-cracker and it unexpected explodes only 2 feet from your ear? According to the inverse square law, the sound source is now 5 times closer, so the intensity is 25 times louder! At your ear, that sound pressure level might now be as high as 160-dBA and enough to cause instant hearing damage.
3 Rules to Help Prevent Hearing Loss
- Limit Your Exposure to Loud Sounds. The louder a sound, the shorter the time we can safely be around it without permanently damaging our hearing. So, if a noise or environment is loud—think chainsaw, concert, music, equipment, etc.—limit your exposure time!
- Maintain a Safe Distance from Loud Noises. The more distance you can put between your ear and a loud noise source the better. Get further away from a speaker at a concert. Don’t use power equipment close to your head/ears. Maintain a safe distance from machinery.
- Use Hearing Protection. When in doubt, use hearing protection. Cheap, foam earplugs, when installed properly, decrease sound pressure levels 15-20-dB. If you were paying attention to my math earlier, that is lowering the sound intensity by a factor of 6-7 times. That is enough to protect your hearing from most any noise at least for short term exposure.
Think You May Be Experiencing Hearing Problems?
If you think you may be experiencing symptoms of hearing loss, call Advanced Hearing Solutions to schedule a consultation today. We will test and explain your hearing levels to help you better understand your individual hearing needs.