NoiseCapture App is an application to evaluate the sound pollution of your environment. With this app you can make a measurement that will inform you about endured exposure. In addition, you can contribute to create collaborative noise pollution maps by transferring this information completely anonymously.
Download: Android 4.0.3 (2.69MB)
Runs offline: partially (you need a connection to send the data and consult the map)
Last update: Android 31/08/2017 (v. 1.0.1)
Website of the developer: Noise Planet
NoiseCapture supports a citizen science project whose objective is to record the levels of noise endured by users. In addition to discover the noise pollution you suffer, you can share that information and contribute to the creation of collaborative noise pollution maps voluntarily and anonymously.
First of all, it is necessary to calibrate the telephone to be used. To obtain the most reliable measurements possible, a reference value obtained from an already calibrated device is used. However and despite this requirement, the application itself already warns that this utility does not replace in any case a professional sound level meter.
The calibration is carried out as follows:
- Enter in the section Calibration that you will find in the menu in the upper left corner. Confirm that you understand the warning message that will appear on the screen and that indicates the need to use a reference device.
- In the Calibration mode drop-down list, select the frequency in relation to which you want to calibrate the device. To take into account all frequencies, select Global.
- Press the Start button. For a short time, the app performs a heating phase, which you can leverage to prepare the reference device. Then the real calibration begins. In order to obtain the highest accuracy, the measurement duration must be the same on both the telephone and the reference device.
- Once the measurement is complete, enter the value registered by the reference unit in the Reference value field and press Apply. You can also reset the measurement.
- Finally, test the calibration using the Test gain option. You have to compare the results obtained with the previously calibrated apparatus. A difference of 0.5 decibels (dB) between the two devices is considered acceptable.
How noise measurement is performed
Once the device is calibrated, noise measurement can be carried out with certain guarantees. The steps to follow are those:
- Entering in the Measurement option, press the Record button represented by a microphone (you can stop it when you want). On the screen you will see the noise level in dB represented by an oscillating number and a bar graph. You will also be able to observe the maximum, minimum and mean levels, a chronometer or the GPS accuracy, as well as a sound spectrum.
- You can typify the measurement by providing a description, the degree of nuisance generated, the conditions in which the measurement was performed and the predominant sources (recommended, although it isn’t a prerequisite). The measurements are sent by default to the server, although you can disable this in Settings > Data transfer. The logs are also stored locally on your phone and are accessible from the History option. From this last section you can also upload your measurements manually, as well as download the metadata in ZIP format, edit the description, etc.
Considerations for a real measurement of noise pollution levels
Users of NoiseCapture who want to know and share noise pollution information should consider the following good practices:
- Use a calibrated device.
- Keep the phone in your hand, avoid storing it in a pocket, handbag, etc..
- Avoid masking the device’s microphone.
- Use an external microphone (if possible).
Also, if you want to share your data to create noise maps, remember the following:
- Take measurements outdoors (do not send indoor measurements).
- Wait for the GPS signal to be as accurate as possible.
- Complete the description of the measurement.
Images: screenshots 26/09/2017. © Noise Planet
A recent paper of the Barcelona Institute for Global Health affirms that «traffic noise is a major health problem responsible for annoyance and sleep disturbance in many people». In the specific case of the Catalan capital, the daily average to which its citizens are exposed is 65.1 dB during the day and 57.6 dB at night, values that exceed those recommended by the WHO (55 and 40 dB respectively. In fact, Barcelona is one of the noisiest cities in Europe). However, it’s a problem that affects a large percentage of European citizens and for which there is an alarming lack of data, as reported at the 6th Ministerial Conference on Environment and Health held in June 2017 in the Czech Republic (Factsheet 6. Reducing noise to promote health).
Citizen science and initiatives such as NoiseCapture can complement the monitoring work that must be carried out by public administrations, thereby alleviating this lack of information that is key to adopting the most appropriate measures. In this sense and although the application under analysis shows a carefully design, both from the point of view of its operation and the experience intended to be transmitted to the user, the calibration process required to obtain reliable measurements can restrain its use. However, it is a tool that could be perfect as a complement to a citizen science workshop that addresses the issue of environmental noise and the effects of noise pollution on health. In this case, it would be relatively easy to take sound level meters used by the administration or by local police forces and use them for the calibration of the devices of the volunteers. Also, it might be useful to see what possibilities the application offers for the record of indoor measurements (without violating aspects related to data protection), since as Robert E. McGrath states in an interesting article where he analyzes this app, we spend a large part of our time inside enclosed spaces.