How does noise affect workers’ health?

In modern life, noise has become an unavoidable part of our daily environment, yet few truly realize the significant impact it has on our health and mental state. In the workplace, noise is a concerning issue; it not only affects work performance but also disrupts the daily life of workers. From the sounds of operating machinery to transportation noise, it impacts not only the ears but also penetrates the human soul.

So, let’s explore in more detail how the negative effects of noise affect workers’ health.

1. What is noise?

Noise refers to mixed sounds that cause discomfort and can be harmful to the body.

Sound or audio is the vibration of objects that propagates through elastic media such as air, liquid, or solids.

Sound frequency is the number of vibrations per second, measured in Hertz (Hz).

Sound pressure: when sound travels through a medium, it creates a compressive force called sound pressure (also called acoustic pressure).

The audible range of human hearing is from 20Hz to 20,000Hz. Sounds below 20Hz are inaudible (infrasound), and sounds above 20,000Hz are ultrasound.

Noise intensity is the energy of chaotic sounds moving through the air in one second across a horizontal plane in the direction of the noise per 1 cm².

• If the noise intensity is too low, humans cannot hear it.
• If the noise intensity is too high, it can cause ear pain and discomfort.

There are two types of noise:

• Stable noise (continuous noise): noise with a maximum intensity higher than the minimum intensity < 7dB.
• Unstable noise: noise with a maximum intensity higher than the minimum intensity > 7dB, including intermittent noise (> 1 second) and impulse noise (< 1 second).

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2. Sources of noise inside manufacturing plants

Inside manufacturing plants, noise can originate from many sources depending on the production process and related activities. Some sources include:

• Machinery and equipment during production often generate high and continuous noise. Engines, compressors, generators, welding machines, metalworking machines, cutting machines, and grinders are major noise sources.
• Production activities such as heat pressing, machining, crushing, transportation, and packaging can also generate noise.
• Ventilation systems, industrial fans, air compressors, and air conditioning systems may also contribute to plant noise.
• If there is transportation activity around the plant, noise from vehicles, tractors, forklifts, and other transport methods may affect the working environment.
• Unexpected factors like breakage, explosions, banging, or collisions during work may also occur.

Identifying specific noise sources and assessing the noise level in the workplace is important to implement effective noise control measures to protect workers’ health and mental state.

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3. Occupations exposed to harmful noise

Many industries produce noise exceeding permissible limits, and prolonged exposure to high noise can reduce hearing ability and even lead to occupational deafness, affecting workers’ health and mental state. Some high-risk occupations include:

• Manufacturing industries like automobile production, metal casting, wood production, plastics, food, and paper industries, which operate in noisy environments.
• Construction: noise from excavators, compressors, drills, and other tools can pose risks. Large construction projects like bridges, highways, and tunnels also generate high noise.
• Aviation and transport: pilots, flight attendants, and airport staff are exposed to noise from aircraft engines, vehicles, and other operational activities, risking hearing and general health.
• Agricultural activities using tractors, harvesters, sprayers, and air compressors can produce significant noise.
• Other industries and jobs exposed to high noise levels.

These are just some examples, but noise exists across many industries. Evaluating and controlling noise is essential to protect workers’ health.

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4. How noise affects workers’ comfort

Noise can affect workers’ comfort and mental state in the workplace. Its effects can be categorized into two main types:

• Direct impact on the auditory system: higher noise levels increase the risk of hearing damage, reduced hearing, and occupational deafness.
• Beyond hearing, noise affects the nervous system, cardiovascular system, digestive system, causing fatigue, reduced health, lower productivity, and higher risk of workplace accidents.

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5. Permissible noise exposure levels in the workplace

According to QCVN 24:2016/BYT National Technical Regulation on noise – Permissible noise exposure levels in the workplace:

• Workers’ noise exposure at the workplace must not exceed the values specified in Table 1.

Table 1. Permissible sound pressure limits by exposure time

Noise exposure duration	Permissible equivalent sound pressure level (LAeq) – dBA
8 hours	85
4 hours	88
2 hours	91
1 hour	94
30 minutes	97
15 minutes	100
7 minutes	103
3 minutes	106
2 minutes	109
1 minute	112
30 seconds	115

At all times while working, the maximum sound pressure (Max) must not exceed 115 dBA.

• Permissible sound pressure limits at specific work positions are shown in Table 2.

Table 2. Permissible sound pressure limits at work positions across octave bands

Work position	General or equivalent sound pressure level not exceeding (dBA)	Sound pressure in octave bands with center frequency (Hz) not exceeding (dB)
		63	125	250	500	1000	2000	4000	8000
1. At direct production work positions	85	99	92	86	83	80	78	76	74
2. Remote monitoring and control rooms without telephone communication, laboratories, experimental rooms, and machine equipment rooms with noise sources.	80	94	87	82	78	75	73	71	70
3. Remote monitoring and control rooms with telephone communication, coordination rooms, precision assembly rooms, typing rooms.	70	87	79	72	68	65	63	61	59
4. Functional rooms, administrative, accounting, planning offices.	65	83	74	68	63	60	57	55	54
5. Intellectual labor rooms, design research, statistics, programming, theoretical labs, and experimental data processing.	55	75	66	59	54	50	47	45	43

At all times while working, the maximum sound pressure (Max) must not exceed 115 dBA.

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6. Occupational diseases caused by long-term exposure to harmful noise

Prolonged exposure to high-intensity noise can cause health problems and occupational diseases such as:

• Harmful noise can cause gradual hearing loss, affecting the ability to perceive sounds, communicate, and reducing quality of life.
• Loud and continuous noise can cause tinnitus, a ringing or buzzing in the ears, which may affect sleep, concentration, and in severe cases lead to prolonged auditory disorders.
• Cardiovascular diseases such as hypertension, coronary artery disease, and heart disease.
• Stress and psychological issues: continuous noise may cause stress, leading to anxiety, depression, irritability, reduced work productivity, and tension.

To protect health, it is important to minimize exposure to harmful noise by using ear protection (earplugs or noise-canceling headphones) and following occupational safety regulations.

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7. Measures to reduce the impact of noise on workers’ health

Harmful noise can negatively affect workers’ health and performance. Measures to reduce noise impact include:

• Technical solutions such as installing soundproof materials, using noise barriers, and periodically checking, maintaining, and servicing noise-generating equipment to minimize noise levels.
• Providing appropriate ear protection such as earplugs or noise-canceling headphones to workers to reduce direct noise exposure and protect hearing.
• Compliance with noise safety regulations set by labor authorities, including establishing permissible noise limits, providing protective measures, and training employees on noise-related safety and health.
• Training workers: Train employees on health protection measures to enable them to protect themselves when working in noisy environments.
• Periodically conducting occupational environment monitoring in factories, collecting and analyzing harmful factors to adjust and reduce hazards, preventing occupational diseases.

These measures help reduce noise impact on workers’ health and improve work efficiency.

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8. National labor environment monitoring center

Nam Viet Labor Environment Monitoring Center is a professional unit for monitoring and measuring occupational environment quality across all provinces in Vietnam. With experienced monitoring specialists, the center uses modern measurement equipment ensuring accuracy and reliability.

REGISTER FOR LABOR ENVIRONMENT MONITORING SERVICE

In addition to monitoring services, the center supports clients in planning, handling, and following up on labor environment issues. With the motto “customer-centered,” the center ensures client satisfaction and provides optimal solutions for businesses.

With investment in technology and manpower, Nam Viet’s monitoring center has become a reputable unit in occupational environment monitoring in Ho Chi Minh City with objectives such as:

• Maintaining brand reputation and service quality.
• Providing clients with the best and most suitable solutions.
• Working with experienced Masters and Engineers to protect the environment and benefit businesses.

• With Nam Viet Environmental Monitoring, your company will receive professional service and the best cost advantages.

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9. Labor environment monitoring service pricing

To help businesses conduct professional and efficient labor environment monitoring, Nam Viet provides clients with a pricing table for labor environment monitoring services with quality and reasonable cost.

• The pricing table provides detailed information about the monitoring services, including travel, measurement, analysis, and reporting costs. Clients can trust the accuracy and reliability of the monitoring reports.
• We commit to offering competitive and reasonable prices and are ready to provide professional consultation and support for any service-related questions.
• With Nam Viet’s pricing table, clients can easily select service packages that suit their needs, ensuring maximum satisfaction with professional service quality.