What is infrasound?
Infrasound refers to sound waves with frequencies below 20 hertz (Hz). These frequencies fall below the normal range of human hearing and are therefore often not perceived as conventional sound. Nevertheless, under certain conditions, they can be felt as a sensation of pressure, vibration, or a hum.
Since infrasound and low-frequency sound are often not clearly audible, those affected frequently find it difficult to identify them. This makes it all the more important to identify potential exposure through appropriate measurement.
Where is infrasound produced?
Infrasound occurs naturally in our environment. Natural sources include, among others:
- Wind and Storms
- Thunderstorm
- Ocean surf
- Waterfalls
- Earthquake
- Volcanoes
In addition, there are numerous technical sources of infrasound and low-frequency sound:
- Heat Pumps
- Ventilation and Air Conditioning Systems
- Compressors
- Transformers
- Industrial facilities
- Traffic
- Airplanes
- Speaker Systems
- Large Engines and Machinery
Building services systems or poorly decoupled equipment can also generate vibrations and humming noises. Since low frequencies travel relatively far and can cause structural components to vibrate, these disturbances do not occur only outdoors. They can also be detected in living spaces, offices, or technical facilities.
How is infrasound assessed?
Unlike many air pollutants, there is no universally applicable limit value for infrasound.
The evaluation is frequency-dependent and takes various factors into account:
- Sound pressure level
- Frequency spectrum
- Exposure time
- Time of day
- Measurement location
- Environmental Conditions
In Germany, low-frequency noise emissions are assessed based on, among other things, the TA Lärm and DIN 45680.
A particular challenge is that traditional sound level measurements in dB(A) only capture low frequencies to a limited extent. As a result, relevant infrasound components or low-frequency noises may sometimes be underestimated in conventional measurements. Appropriate measurement methods are therefore necessary for a meaningful assessment.
What effects can infrasound have?
Infrasound is often associated with health problems. However, the scientific evidence paints a more nuanced picture.
Based on current knowledge, no confirmed adverse health effects have been demonstrated for infrasound levels below the threshold of perception.
However, if infrasound or low-frequency sound is perceived, it can be experienced as disturbing or distressing. Those affected report, for example:
- A sense of tension in the room
- Humming
- Sensitivity to Vibration
- Noises that are difficult to pinpoint
- Vibrations in furniture or structural components
In cases of noticeable or more severe stress, the following symptoms may also occur:
- Concentration disorders
- Sleep disorders
- Fatigue
- Headache
- Malaise
- Stress Responses
At extremely high sound pressure levels, pain when listening or hearing damage is always a possibility.
Why a measurement might be useful
Subjective perception is often difficult, especially with low-frequency sound. Many people affected describe an unpleasant sensation but are unable to clearly identify the cause.
Taking a measurement helps to
- To objectively record sound events,
- to reveal temporal patterns,
- to identify technical sources of noise,
- To substantiate findings with specific measurement data.
This is particularly helpful when symptoms occur only at certain times of the day or may be related to heat pumps, ventilation systems, industrial facilities, or traffic.
Measuring infrasound with the air-Q
The air-Q enables the continuous monitoring of infrasound and other environmental parameters. This allows not only the detection of sound events and potential disturbances, but also their analysis over time.
One particular advantage is that noise measurements can be combined with other environmental data. This makes it possible to identify potential correlations between complaints and factors such as
will be examined.
This provides a more comprehensive picture of the environmental conditions than a sound measurement alone.
Conclusion
Infrasound is a natural part of our environment and is also generated by numerous technical systems. Although infrasound is often not directly audible, low-frequency sound events can be perceived as disturbing under certain conditions.
Since the assessment is complex and conventional sound measurements often have limited ability to detect low frequencies, targeted measurements play an important role. The air-Q allows for the continuous monitoring and analysis of infrasound, sound events, and other environmental parameters. This enables potential sources of noise pollution to be better understood, documented, and classified.
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