Rodney Taylor, Doctor of Audiology, Advanced Studies in Tinnitus and Hyperacusis, Certified by the American Institute of Balance for Concussion and Vestibular Rehabilitation.
Noise is a serious hazard in many workplaces and environments. Over an extended period of time, if hazardous exposure to noise from machinery and equipment is not eliminated or controlled, it may cause permanent hearing loss and tinnitus.
Many professions put individuals at risk for ear damage from noise including: firefighters, military personnel, disc jockeys, subway workers, construction workers, musicians, farm workers, industrial arts teachers, highway workers, landscapers, factory workers, and cab, truck, and bus operators, among others. The U.S. Environmental Protection Agency (EPA) estimated that approximately nine million workers are exposed to work noise. Recreational activities such as hunting, target shooting, motorboating, waterskiing, jetskiing, snowmobiling, motorcycle riding, woodworking, listening to rock music, and wearing stereo headsets are also sources of potentially hazardous noise. Other sources include movie theatres, home entertainment centers, car stereo systems, health clubs, nightclubs, bars, and amusement centers. An individual may also be exposing themselves to excessive noise with a long daily commute in heavy traffic, or by using household appliances for extended periods.
Exposure to higher levels of noise in the workplace not only results in hearing loss, but also physical and psychological stress, and can result in reduced productivity. It can interference with communication, and contribute to accidents and injuries by making it difficult to hear potential warning signals. Hearing loss can have a significant impact on the quality of life for individuals affected in addition to their families. There has been a recent interest in noise exposure and hearing loss. A recent study from 2014, has shown that even chronic exposure to moderate levels of noise (60-80 dB) can have a significant effect on hearing. This contradicts current National acceptable noise exposure levels in both Canada and the U.S.A.
What is Hazardous Noise?
Sounds that exceed 80 dB are considered potentially dangerous. The determining factors in noise-induced hearing loss are the amount of noise that an individual is exposed to, in addition to the duration of the exposure.
The National Institute for Occupational Safety and Health (NIOSH), an organization of the Centers for Disease Control and Prevention in the U.S., recommends that workers and others in loud environments should not be exposed to sounds over 85 dB over an eight hour period. Industries such as mining, construction, oil-gas well drilling, and servicing and agriculture, as well as the U.S. Air Force and the U.S. Army, use this exposure limit of 85 dB for an eight-hour workday. European Union Standards recommend the same. The Workplace Safety and Insurance Board of Ontario is less conservative and recommends 90 dB over an eight hour period.
Sensory cells in the auditory system can be damaged by intense brief impulse sounds such as an explosion, or by continuous and repeated exposure to noise. For a list of common sounds, please see the section on the website entitled How Loud is Loud?. More recent research shows that even chronic exposure to moderate levels of noise have a significant effect on hearing levels. In such a case, it is more difficult to assess the risk factor as individuals may not suffer from any type of temporary threshold shift.
Warning Signs of Hazerdous Noise
Below is a list of signs that you may be causing damage to your hearing due to hazardous noise.
- You must raise your voice in order to be heard
- You cannot hear someone that is two feet away from you
- Speech around you sounds muffled or dull after leaving a noisy area
- You have pain or tinnitus after exposure to noise
For the more current research on moderate level noise exposure, an individual may remain without the above symptoms.
How Damage Occurs
The current general consensus is that sounds of less than 80 dB, even after longer periods of exposure, are unlikely to result in hearing loss. More recent research has refuted this, indicating that moderate level sounds that and individual is exposed to chronically, may have a deleterious effect on hearing levels. Individual’s sensitivity to noise vary greatly, so it is impossible to predict how an individual will respond to noise. It is well documented that exposure to a one-time-only or continuous noise, if hazardous enough, can cause temporary hearing loss. A Temporary Threshold Shift is defined as a temporary decrease in hearing levels after hazardous noise exposure that recovers approximately 16 to 48 hours after the exposure.
Hearing loss occurs when loud sounds cause damage to the cilia located in the cochlea. Once destroyed, these cells do not regenerate and permanent damage occurs. Once damaged, the transmission of the electrical impulses becomes permanently altered. Although much current research is being dedicated towards the regeneration of Inner and Outer Hair Cells, results are questionable and it has certainly not advanced to a treatment stage.
Protecting your Hearing from Damage
Healthy hearing habits can help to prevent hearing loss and/or tinnitus. Without proper measures, the effects of hazardous noise can result in the degradation of an individual’s hearing and worsen existing tinnitus. If you have one of these two conditions, protect your ears from further damage. Better yet, take immediate measures to protect your hearing
regardless if these conditions exist.
The general consensus is that individuals should utilize effective ear protection when they are exposed to sounds above 85 dB. Properly fitted or custom ear protective devices are essential. Some researchers are advocating the use of some minimal protection for those that are exposed to moderate levels of sound on a continual basis.
Most individuals do not carry around a sound level meter, and it becomes difficult to be sure when the environment is too loud. A general rule of thumb is if you are standing two to three feet away from an individual and you are unable to understand what they are saying, the noise level has the potential to cause damage to your hearing. A few other indicators of exposure to hazardous noise levels include: if you must raise your voice in order to be heard, speech around you sounds muffled or dull after leaving a noisy area, or if you have pain or tinnitus after exposure to noise.
Prevention is the key in dealing with hazardous noise. It is not always possible to eliminate or control the noise in the workplace or environmentally, so it is important to keep it as low as possible.
What Can I do to Limit my Exposure
Wear ear protection when exposed to loud or potentially damaging noise. Environments to be conscious of include; a noisy workplace, heavy traffic, rock concerts, hunting, mowing the lawn, snow blowing the driveway, using a chainsaw, etc. Cotton in the ears will do nothing to protect your hearing from loud noises. Effective hearing protection includes ear muffs and custom ear protection. Advanced Hearing Aid Clinic and Advanced Hearing and Balance Institute offers a wide variety of ear protective devices, both custom and over-the-counter. Ear protective devices are a wise investment. Audiologists at our clinics assess the effectiveness of the earmolds that we sell by measuring the true noise reduction values at each frequency with Real Ear Measurements. See the section Custom Ear Protection on this website for further information.
It is essential that you limit your periods of noise exposure. Try to avoid sitting next to the
speakers at concerts, nightclubs, or auditoriums.
One in three individuals owns an iPod or MP3 stereo. When using stereo headsets or listening to music on a stereo, try to decrease the volume and keep it at a safe level. If a friend can hear the music from your headphones and they are standing three feet away, the volume is too loud. You are more likely to keep the sound at a manageable level using iPods or MP3s with a custom made plug as it blocks out the ambient background noise.
When purchasing recreational equipment, children’s toys, household appliances, power tools, MP3/iPods, hairdryers, etc., look for a noise rating. Choose quieter models, especially for the equipment that is most often used. It is especially important to check for noise level ratings on children’s toys. Children often hold toys close to their ears. There is much current research on the increased susceptibility of hearing loss in younger ears. Interestingly, Advanced Hearing Aid Clinic did a cursory study of Noisy Toys in conjunction with the Ottawa Sun, which made front-page news. We have remained staunch advocates for the passing of acceptable limits for children’s toys in Canada.