Noise Dosimetry: Understanding Noise Pollution and Measurement

This article delves into the topic of noise pollution, providing an overview of noise dosimeter equipment and the process known as noise dosimetry (the measurement of noise radiation). We’ll also touch upon some prominent noise dosimeter vendors.

Understanding Noise

The term “noise” generally refers to any unwanted sound energy produced by a vibrating body. Sound energies can be categorized into two types: audible and unaudible.

Audible sound falls within the frequency range of 20Hz to 20KHz. Sounds with frequencies below 20Hz are known as infrasonic, while those above 20,000 Hz (20KHz) are called ultrasonic.

Noise can be continuous or intermittent, and can also be classified as high frequency or low frequency. In any system, noise can be thought of as having three elements: the source, the transmission path, and the receiver.

Noise originates from various sources, including:

• Domestic: Mixers, utensil movement, etc.
• Commercial: Automobiles, planes, laboratories, etc.
• Industrial: Transport vehicles, generators, boilers, etc.
• Natural: Bird and animal calls, wind, sea tides, etc.

Noise Pollution and Control Techniques

While numerous sources contribute to noise, road traffic is often considered a primary source of noise pollution.

Noise levels are typically measured in decibels (dB) or A-weighted decibels (dB(A)), where dB(A) represents A-Weighted Sound Pressure Levels (SPL). Noise pollution occurs either at the source or along the transmission path before reaching the receiver.

Several techniques can be employed to control noise pollution:

• Reducing noise levels from domestic sources
• Regular maintenance of machines and automobiles
• Controlling vibrating devices
• Reducing sound emitted from loudspeakers
• Speaking in a low voice

Noise Level Measurement Equipment

The following table outlines various noise level measurement equipment and their specific functions:

3M Noise Dosimeter Specifications

Here are some specifications of the 3M noise dosimeter (e.g., model eg5-D):

• Easy USB connection with PC and Detection Management Software.
• Noise measurement range: 70 to 140 dB.
• Supports 5 independent noise dosimeters.
• Displays parameters: L_AVG, L_EQ, SPL, Dose, Min/Max levels, TWA, SEL, etc.
• Indicators: Battery, Dose exposure indicator
• Battery life: 40 hours.
• Meets ANSI S1.25, IEC61252, and other intrinsic safety standards.

Noise Dosimeter Vendors

The table below lists several noise dosimeter vendors and their products: