Noise Maximum Value Measure Sound Level Meter Icon

Noise maximum value (Lp_max)

The noise maximum value, unlike the basic stressful "normal" noise value, reflects acute noise events - such as a short loud bang in the night. These events documented by the noise maximum value can abruptly interrupt rest phases and cause stress.

Can be measured with:

✓ Measurable with air-Q light, air-Q basic and air-Q pro as well as air-Q science


The air vibration generated by sound can be measured and is referred to as sound pressure level. The human ear can perceive sound pressure in a range between 20 µPa and 200 Pa. The loudness of sound is measured in decibels (dB).

The main cause of noise in Europe is traffic noise caused by road, air and rail traffic. Around 40 % of people in European countries are exposed to road noise of over 55 dB (decibels).

The maximum noise - value indicates the maximum sound level within a 2-minute period. If there is a loud bang (e.g. by a slamming door), this will be seen in the historical data of the noise (max-value). While in the normal noise measurement value this very short loud noise is lost, because in live data it is only seen briefly or averaged over a 2-minute period.

Limit values for noise:

In the Federal Immission Control Act TA Lärm, maximum limits are set for indoor areas (25 dB at night, 35 dB during the day). In outdoor areas, different limits apply to different areas. In spa and recreation areas 45 dB (day) and 35 dB (night) apply, in pure residential areas 50 dB (day) and 35 dB (night), in mixed areas 60 dB (day) and 45 dB (night), in commercial areas 65 dB (day) and 50 dB (night).

In order to prevent health impairment, the WHO sometimes makes stricter recommendations for maximum sound levels of certain noise sources. Accordingly, the limit for a long-term noise level is 40 dB (at night) and 65 dB (during the day). For traffic noise the recommendation is a maximum of 53 dB (day) and 45 dB (night), for rail traffic 54 dB (day) and 44 dB (night), for air traffic a maximum of 45 dB (day) and 40 dB (night). According to the WHO, the noise level caused by wind turbines should be less than 45 dB during the day. In general, noise at the same sound pressure level is perceived as having different levels of impact - rail noise, for example, is the least sleep-disturbing, aircraft noise the most.

The Noise Vibration Workplace Protection Ordinance (LärmVibrationsArb SchV) applies to protection against noise effects at the workplace. Depending on the type of activity, duration and specific location of the noise exposure or the volume of noise occurring for a short time, various limit values are specified.

Designationning Bordervalues noise
Federal ImmissionprotectionTA Noise Act - Indoor Daytime 35 dB
Nighttime 25 dB
Federal ImmissionprotectionTA Lärm - Spa Areas During the day 45 dB
At night 35 dB
Federal ImmissionprotectionTA Lärm - Pure residential areas During the day 50 dB
At night 35 dB
Federal ImmissionprotectionTA Lärm - Mixed areas Daytime 60 dB
Nighttime 45 dB
WHO recommendation Wind turbines near residential areas During the day 45 dB

Consequences of too much noise:

High sound peaks and continuous sound stress the hearing. The hair cells in the inner ear are permanently damaged by noise, which limits acoustic perception. Since these hair cells do not grow back, noise-induced damage is irreparable and ultimately leads to hearing loss. In addition, temporary or even chronic ringing in the ears (tinnitus) can develop.

As a psychosocial stress factor, sound pollution can also severely reduce well-being and thus the quality of life. If noise is perceived as a disturbance or nuisance, dissatisfaction and irritability arise. Since communication and attention suffer, performance decreases. Especially at night, sleep disturbances can occur. Mental illnesses can also be triggered by noise.

Physical stress reactions to noise affect the entire organism, the nervous system and the hormonal system. This leads, among other things, to changes in blood pressure and heart rate and has an influence on blood lipids, sugar and coagulation. The impaired regulation of the circulatory and metabolic systems can lead to cardiovascular diseases or arteriosclerosis.

Emergence from noise:

Inside living and working spaces, air conditioning, ventilation systems and various machines and devices are often causes of noise. External factors include traffic noise, construction sites and other public works, sporting and cultural events. In addition, schools, kindergartens, public places as well as animals and catering facilities contribute to noise generation.

The assessment of when sound is perceived as noise depends on various factors (so-called moderators). These include the distance as well as the visibility of the sound source, the time or the significance of the noise problem in public perception. Subjective aspects also play a role, such as individual sensitivity to noise, age, type of activity or location.

Sensor used:

Noise is measured in the air-Q by means of an RMS converter. A microphone transmits the vibrations into an RMS converter, which creates a voltage level from the incoming power, which can be converted into a decibel value. The advantage of our sensor is that there is no audio recording and actually only the sound pressure is measured. This makes the Noise Sensor much more accurate than various smartphone apps that fake this accuracy. The noise maximum value, unlike the normal noise value, always reflects the maximum value over two minutes. This means that even short noise events can be detected in the historical data.

The small fan of the particulates sensor built into the air-Q itself generates a low noise level, which is, however, filtered out and is no longer measurable in the night mode of the air-Q (fan deactivated).

Measure noise, noise level and loudness:

Measure noise, noise level and volume as well as pollutants in the indoor air of the office or home in real time - with the air-Q air analyser, which can be ordered here.

air-Qs, which use the sensor for

Noise maximum value (Lp_max)


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air-Q Air Quality Meter

Monitor air quality, all air components and environmental influences with the air-Q. For your health and performance.