Noise detection involves the identification of sounds and their sources that interfere with people's learning, work, and daily life. This includes: noise detection in various urban functional zones, traffic noise detection, regional environmental noise detection, and noise source detection. Noise is a type of sound, which is a combination of various frequencies of sound waves.

China's "Environmental Noise Pollution Prevention Law of the People's Republic of China" defines environmental noise pollution as any noise that exceeds the national standard for environmental noise emissions, and disrupts others' normal lives, work, and studies. Decibels (dB) are the unit for sound pressure level, used to indicate the loudness of sound. The "Urban Area Noise Standard of the People's Republic of China" specifies the maximum allowable environmental noise levels for five types of urban areas: health resorts, high-end villa areas, high-end hotel areas, with daytime levels at 50dB and nighttime levels at 40dB; residential and cultural and educational institutions-dominated areas, with daytime levels at 55dB and nighttime levels at 45dB; residential, commercial, and industrial mixed areas, with daytime levels at 60dB and nighttime levels at 50dB; industrial areas, with daytime levels at 65dB and nighttime levels at 55dB; and for major urban traffic arteries, inland waterways, main and secondary railway lines, with daytime levels at 70dB and nighttime levels at 55dB (nighttime refers to 10 PM to 6 AM the next morning).

In accordance with national standards, residential noise levels must not exceed 50 decibels during the day and should be below 45 decibels at night; exceeding these levels can be harmful to human health. Article 5, Paragraph 4 of the National "Measuring Methods for Environmental Noise in Urban Areas" stipulates that when noise measurements are taken indoors, the indoor noise limit should be 10dB lower than the standard value of the respective area.

Noise is a type of sound that causes annoyance or is loud enough to harm human health.

From an environmental protection perspective: Any sound that hinders people from resting, studying, or working, or that interferes with the sounds they wish to hear, is considered noise.

From a physics perspective: Noise is the sound emitted by an object during irregular vibrations.

Noise Detection Partial Testing Standards Include:

GB2237-2008 Social Living Environment Noise Emission Standard

GB/T 12348-2008 Industrial Enterprise Boundary Environmental Noise Emission Standard

GB3096-2008 Noise Environment Quality Standard

GB12523-2011 Construction Site Environmental Emission Standard

GB/T17248.3-1999 Acoustics – Noise emitted by machinery and equipment – Measurement of sound pressure levels at work positions and other positions

GB12525-1990 Railway Boundary Noise Limitation Values and Their Measurement Methods