Ear protection

Ear protection refers to the use of personal protective equipment (PPE) to protect and preserve an individual's hearing. The PPE, in this case, tend to be different types of ear devices that block sound from entering the ear. Depending on the environment, different types of ear protection may be required. Any environment where sound above 85 decibels (dB) can damage hearing, especially with repeated or prolonged exposure.

Generally, the best method to reduce the effects of noise on an individual and their hearing is to reduce or eliminate the noise at the source. This can be done through engineering but can be expensive, complicated, and in some cases, impossible. Where not possible, workers are often, depending on the jurisdiction, required to wear ear protection to reduce or eliminate the amount of noise that reaches the ears.

Example of the tiny hairs in the inner ear which can be damaged by excessive noise.

Noise-induced hearing loss (NIHL) and tinnitus occur when the tiny hairs inside the cochlea of the inner ear are damaged. This damage is typically due to exposure to excessive noise. Once damaged, these hairs cannot be repaired by the body, surgery, or other medical intervention, which is partially why ear protection is important at every age. The two biggest impacts of hearing loss are aging and noise exposure. While aging remains the largest reason most people lose their hearing, noise exposure is the next biggest reason and a controllable reason.

Hearing protection is, as noted above, required when a person is exposed to over 85 dB. Depending on the source of the sound, damage can be a result of prolonged exposure to these sound levels or can come from sudden, explosively loud sounds. The following are common circumstances sounds are found above these thresholds:

• Busy streets, auto races, motorcycles, dirt bikes, snowmobiles, and tractors
• Sporting events, fireworks displays, and band and orchestra rehearsals or performances
• Industrial, warehouse, farm, landscaping, and loud workplace settings
• Emergency vehicle sirens
• Shooting sports

Much of what is noted above, especially the damage to the ears, is reason enough to wear ear protection in loud environments. Still, often individuals do not understand the importance of hearing and preserving their hearing until they experience hearing loss. Along with this comes an understanding of how important hearing is to an individual's lifestyle. Some reasons to use ear protection include the following:

Diagram of the delicate inner workings of the ear.

The ears are delicate, and the parts of the ear that play an important part in hearing are even more delicate. Sounds are collected from the outer ear and funneled into the eardrum, where they are amplified in the middle section of the ear as vibrations. They are then sent to the cochlea, or inner ear, where they are turned into an electrical impulse that travels along an auditory nerve to the brain, which ends in the sensation of hearing a sound. Any damage to this process causes drastic changes to one's ability to hear. And once the ear and its hearing capabilities are damaged, they cannot be fixed. An individual can wear hearing aids to cope with the damage, but the damage is permanent.

Protecting an individual's hearing can save them from spending significant money in the long run, as they could later have to cope with the expense of hearing damage. Monetary considerations seem frivolous compared with the concern of permanent hearing loss, but compared with ear protection, it is significantly more expensive to pay for hearing aids, the long-term health impacts, and other related health needs that occur from hearing damage.

Hearing, as noted above, is important to an individual's way of life—from answering the doorbell or hearing the bleat of a car's horn—and it is important to be able to hear to navigate the world. And when an individual fails to hear correctly, they tend to compensate by speaking loudly or asking people to repeat themselves, which can lead to miscommunication, accidents, and confusion. Hearing loss can also cause an individual to miss emergency sounds, such as alarms, sirens, or other auditory notices of danger.

Tinnitus is a common hearing complaint in which an individual experiences a buzzing or ringing in their ears on a near-constant basis. It has been described as similar to hearing a fire alarm going off constantly in the background. For some, this can last for weeks or months at a time, and for others, it is permanent. Tinnitus is frequently caused by being exposed to overly loud noises, such as drilling, explosions, and loud music. Ear protection can reduce the chance an individual develops tinnitus.

Similar to tinnitus, individuals who have damaged their hearing can develop vertigo, as the ears are required to help maintain an individual's balance. This can be more difficult to live with than tinnitus.

Some workplaces, such as construction sites, industrial sites, manufacturing sites, stamping plants, and garages, can be noisy environments. They are often noisy enough that unprotected exposure to common equipment can lead to damage in an individual's ears sooner than an individual may assume. Other professions, such as musicians, are exposed to loud noises during practices, rehearsals, and performances, which can require ear protection to help keep their hearing—which for musicians is a part of their career. In all of these cases, finding the right level of ear protection is important, especially in an industrial setting where ear protection that is too good can cause an individual to miss safety cautions or alarms and put them in increased danger.

And whether at work or at home, loud noises can occur at random, which can cause hearing damage, which gets more significant the older one gets. Wearing appropriate ear protection, even when working around the house, can help prolong an individual's hearing.

Examples of types of ear protection in different noisy work environments.

If exposed to noise at work or home, which is unavoidable, an individual may wonder what type of hearing protection to use to reduce the noise while also being comfortable and easy to use. Ear protectors fall into three main categories: earplugs, earmuffs, and canal caps. Generally, to understand whether there is a need for hearing protection in a given environment, the rule is that if an individual has trouble hearing or understanding a "normal" tone of voice at a distance of around three feet, then ear protection is required.

When selecting ear protection devices, it is important to ensure the level of noise protected against is adequate without having over-protection. Over-protection can cause other difficulties, such as communicating, hearing warning signals, and isolating workers from their environment. Therefore, there is a protective factor considered suitable for different decibel levels, which is based on the single number rating (SNR) value provided with ear protection. This information is best understood as a guide rather than a substitute for other methods of calculating hearing protection performance which, depending on the jurisdiction, may be required for evaluating the noise of a work environment and dictating the level of ear protection required.

To ensure a piece of ear protection is used effectively, the following are best practices:

• Make sure protectors give enough protection, aiming to get noise levels below 85 dB at the ear
• Target the use of protectors to the noisiest tasks and jobs during a work day
• Select ear protection suitable for the working environment, including how comfortable and hygienic they are
• Consider how they will be worn with other personal protective equipment (some are built to be integrated in other PPE, while some PPE can interfere with the proper functioning of ear protection)
• Provide a range of ear protection from employees
• Do not provide ear protection that overprotects or leads employees to not wear the protection
• Do not make use of ear protection where it is not required either by noise levels or the law
• Do not have a "blanket" approach to the use of ear protection in a work environment, as it can be better to target their use to only noisy environments

When using ear protection, it is important to keep the protective equipment in good condition to ensure it continues to work effectively. This can include maintaining the equipment in good and clean condition, ensuring any seals are undamaged, keeping tension in headbands, making sure the hearing protection has no unofficial modifications, and keeping compressible earplugs soft, pliable, and clean.

With earplugs, there are different types of noise reduction, based partly on the type of ear protection. These include conventional attenuation, which provides the same level of noise reduction regardless of the level of noise, designed to provide a consistent amount of ear protection throughout the wearing day. Or level-dependent attenuation, which provides noise protection based on the level of the noise in the environment. The latter type of ear protection can increase the noise reduction at high-noise levels, which can be effective for variable noise conditions to help workers maintain situational awareness without needing to remove hearing protectors. Level-dependent earplugs are also effective for impulse noises—short, loud sounds that occur for brief periods and at random.

Example of expandable foam plugs.

Expandable foam plugs, as their name suggests, are made of a formable material designed to expand and conform to the shape of a person's ear canal. These plugs tend to be rolled into a thin, crease-free cylinder, intended to fit easily into the ear canal. Some individuals with a small ear canal will have difficulty with typical plugs that may not be small enough for them, but more manufacturers are making smaller sizes.

Common type of pre-molded, reusable earplugs.

Pre-molded plugs are typically made from silicone, plastic, or rubber. They are manufactured to be "one-size-fits-most" or are available in several sizes for small, medium, or large ear canals. Sometimes those wearing these types of plugs need two different sizes for each ear, as the right ear can be a different size than the left. They should seal the ear canal without being uncomfortable, which requires trial and error through different sizes. Also, depending on the manufacturer of the plugs, different models may have different fit directions, but they are typically inserted by pulling up on the ear with one hand and inserting the plug with a gentle rocking motion with the other hand until the ear canal is sealed.

Capable of being used when workers do not need full protection, speech-perceiving earplugs are rated at lower attenuation and allow spoken words to be heard, which can be an advantage in some work environments. These plugs have strategic and integrated cavities that provide softer acoustics and absorb disruptive noises while allowing speech perception.

Common type of canal caps.

Canal caps resemble earplugs and are on a flexible plastic or metal band, with an earplug tip that can be a formable or pre-molded material. They can be worn over the head, behind the neck, or under the chin. Some models include jointed bands to increase the proper seal of the earplug. Canal caps offer greater convenience than other types of ear protection, as they can hang around an employee's neck when quiet or can be quickly inserted when the loud noises begin again. However, some find the pressure from the bands uncomfortable, and not all canal caps adequately block all types of noise.

Various examples of earmuffs.

Earmuffs block out noise by covering the outer ear. They come in many models designed to fit most people and can be low profile, with smaller ear cups, or large to hold extra materials for use in extreme noise. Some can include electronic components to help users communicate or to block impulsive noises. However, with earmuffs, people who have heavy beards or sideburns or those who wear glasses will have difficulty with earmuffs, as the hair or the arms of the glasses will break the seal of the earmuff cushions around the ear. Also, some people find earmuffs to be hot and heavy in some environments. To get around this, some earmuffs are being developed with newer materials to reduce the weight and bulk while still blocking noise, and others are built with two-way communication capabilities.

Another development in earmuffs has been noise-canceling features, developed off similar technology used in noise-canceling headphones. These earmuffs provide cover and protection for the wearer with sound canceling features to block out unwanted or damaging noise, and a wearer can turn the noise-canceling off when needing to hear the environment around them or someone speaking to them. However, the same difficulties that can be encountered with regular earmuffs can be had with these.

Much of the research into ear protection has focused on two main concerns: whether ear protection can effectively protect the ears while giving the user adequate sound localization ability and speech perception, and how to use behavioral science to encourage workers to wear ear protection.

Studies of individual devices and meta-analysis studies have found ear protection to be effective. A meta-analysis (Kwak and Han, 2021) looked at both conventional and level-dependent earplugs capable of attenuating input sounds from 21 to 49 dB and 5 to 22 dB, respectively. Findings suggest the ear protection developed so far is able to attenuate the correct level of noise in the environment. The results from the meta-analysis also found that customized earplugs, when compared to non-customized earplugs, showed better attenuation of noise, suggesting the fit of the ear protection is important to get the best benefits.

Sound localization while wearing ear protection has also been analyzed. Sound localization is defined as the ability to determine what direction a sound is coming from. Sound localization is important for environmental and situational awareness, and the loss of sound localization can cause an individual to enter into danger without meaning to. A study on the impact of hearing protection devices on sound localization performance (Zimpfer and Sarafian, 2014) showed that ear protection did nothing to improve sound localization and interfered with the ability of an individual to localize incoming sounds. This was regardless of wearing passive or active noise reduction ear protection.

Similar to sound localization, the effect of ear protection was studied in the meta-analysis, with many studies and their reported function on the speech perception ability controversial. Many studies have shown that wearing ear protection did not improve speech perception ability. And contrary to some suggestions, ear protection was shown to increase the amount of listening effort required in speech perception, producing cognitive fatigue, which increased in noisy circumstances. However, active noise reduction ear protection has been shown to offer better benefits for speech recognition performance compared to passive noise reduction.

Understanding the potential impact on sound localization and speech perception in a military setting is emphasized, as the loss of sound localization or speech perception can cause a loss of situational awareness and put soldiers at increased risk. Further, a lack of ear protection in military contexts can cause temporary and permanent hearing loss, which can also damage the soldier's situational awareness. Passive versus active earplugs have been tested to find that active earplugs, especially non-linear or selective-to-shooting earplugs, work best, as they selectively reduce high-intensity weapon noise while allowing better speech and environmental hearing. This has been the basis of their popularity in the military.

One development in ear protection specifically designed for the military has been an active approach that uses active noise reduction algorithms to actively cancel noise and enhance the signal-to-noise ratio. The ear protection includes a passive component and an active component, which uses a pre-amplifier and a tiny microphone that can increase the desired signal and increase noise protection to protect the wearer's hearing. These devices have been found effective at lower frequencies, yet ineffective in providing protection from noise higher than 150 decibels. Another issue is with only forward-facing microphones, they can reduce situational awareness and sound localization.

There have been various studies in behavioral science approaches to ear protection, specifically to help encourage workers to wear ear protection and protect their hearing. Many of these studies focus on musicians, as they tend to be self-employed and, therefore, in charge of their own ear protection use, without employers enacting on-the-job rules for ear protection use. Based on some studies, 37 to 58 percent of classical musicians and 46 to 49 percent of rock or pop musicians have hearing loss, while the general population has around 17 percent experiencing hearing loss. Further, 51 percent of musicians, compared with approximately 13 percent of the general population, report experiencing tinnitus. A 2021 Finnish survey of musicians found that only 6 percent reported consistent use of ear protection devices.

Notable interventions for musicians have focused on education and environmental restructuring. But these have been met with limited success, which has led to other potential intervention approaches, including persuasion, incentivization, coercion, training, enablement, modeling, or restriction to increase ear protection use and adherence. These potential interventions are based on the behavioral change wheel, which uses an evidence-based approach to identifying what needs to change within a specific target behavior, which could be extended past musicians.

Along with the increase in studies of and understanding of behavioral approaches to encouraging hearing protection use, there have been advances in understanding noise exposure, the damage it can cause, and the limitations on current measurement situations. Some of these studies have suggested that not all types and causes of hearing loss have been properly identified. Nor has the understanding of the impact of each type of damage and what combinations of damage can do to an individual's hearing. Common medical conditions, such as diabetes, hypertension, and renal disease, need to be explored in relation to their impact on ear damage or protection.

There have been several technological improvements in ear protection. A lot of these improvements have focused on increasing the fit and comfort of ear protection and integrating them with other pieces of PPE, as these are the most frequent complaints about wearing ear protection. Another key advancement in ear protection has been the integration of communication and respiratory protection devices to help workers communicate while wearing ear protection without removing them and to protect them from environmental hazards.

Some advancements in ear protection have included custom-fit earplugs at affordable prices. These are considered an important advancement, as they tend to protect hearing better and are also more comfortable. Ear protection pieces have also been developed with "intelligent" features, which are designed to offer adequate passive hearing protection and can include microphones to detect ambient noise to increase or decrease protection, allow voices to come through for communication, and offer built-in communication. And there have been developments in personal sound exposure monitoring devices that can be integrated into other ear protection devices or related PPE to provide measurements of the levels of noise a worker is exposed to during their day, including ambient and peak noise levels. Measurement capabilities can ensure employees are wearing adequate ear protection.

Another potential development in ear protection, based on research conducted at the University of Iowa in 2020, looked at the potential of identifying molecular receptors that cause hearing loss and using a drug to prevent hearing damage while allowing the individual to hear. The drug selectively blocked the GluA2-lacking receptors in mice, which prevented the mice from experiencing synaptopathy when exposed to noise. This produced similar results as earmuffs, leading them to be called chemical earmuffs.