From the Guidelines
Permitted occupational noise exposure levels should not exceed 85 decibels (dBA) averaged over an 8-hour workday, with a 3 dB exchange rate, as recommended by recent studies 1. This is crucial in preventing occupational noise-induced hearing loss (NIHL), which is an irreversible condition. The study by M. Sliwinska-Kowalska 1 highlights the importance of preventing NIHL, as it is a priority due to its irreversible nature.
Key Points to Consider
- Daily noise exposure (LEX,8h) in noisy environments, such as nightclubs and pubs, can be estimated at 92–95 dB(A), which is approximately 4 times higher than the legally accepted limits 1.
- The risk of developing NIHL is very high for individuals exposed to such high noise levels, especially if they do not use hearing protection devices.
- Occupational hearing loss is preventable through the use of engineering and administrative controls, hearing protection devices, and the monitoring of hearing with audiometric testing 1.
Recommendations for Employers and Workers
- Employers should implement a hearing conservation program when noise levels reach or exceed 85 dBA.
- Workers exposed to high noise levels should wear appropriate hearing protection devices, such as earplugs or earmuffs, which can reduce noise by 15-30 dB when properly fitted.
- Regular audiometric testing is recommended for workers in noisy environments to detect early signs of hearing loss, using methods such as pure-tone audiometry 1.
Importance of Prevention
- Prolonged exposure to excessive noise can cause permanent hearing damage, as well as other health effects, including increased stress, hypertension, and reduced productivity.
- Impulse or impact noise should not exceed 140 dBA at any time, regardless of duration, to prevent further hearing damage.
From the Research
Permitted Occupational Noise Exposure Levels
- The permitted occupational noise exposure levels are not explicitly stated in the provided studies, but the studies suggest that repeated overexposure to noise at or above 85 dBA can cause permanent hearing loss, tinnitus, and difficulty understanding speech in noise 2.
- The studies also mention that exposure to hazardous noise is one of the most common occupational risks, and about 22 million U.S. workers are currently exposed to hazardous occupational noise 2.
- The American National Standards Institute (ANSI) and the Occupational Safety and Health Administration (OSHA) have established guidelines for occupational noise exposure, but these guidelines are not mentioned in the provided studies.
Noise Exposure Limits
- The study by 3 measured sound pressure levels emitted by communication headsets or headphones and found that the diffused-field-related A-weighted equivalent-continuous SPLs reached values of 67-86 dB.
- The study by 4 found that reported occupational noise exposure was higher in the 2010s than in the 2000s, but hearing protection use remained low.
- The study by 5 found that earplug use is effective in preventing temporary hearing loss after loud music exposure, with a time-averaged, equivalent A-weighted sound pressure level of 100 dBA during the festival.
Hearing Protection
- The studies suggest that hearing protection is essential to prevent noise-induced hearing loss, and that earplugs, earmuffs, and headphones can be effective in reducing noise exposure 2, 3, 5.
- The study by 6 found that there is uncertainty among stakeholders about the benefits and possible negative effects of ear protection device use by individuals with autism spectrum disorder.
Occupational Noise Exposure Prevention
- The study by 2 recommends an integrated public health approach that emphasizes noise control over reliance on hearing protection, illustrates the full impact of hearing loss on quality of life, and challenges the cultural acceptance of loud noise.
- The study by 4 suggests that significant education and reinforcement of appropriate hearing protection use for workplace noise exposures is necessary to preserve workers' hearing.