A study of the accuracy of mobile technology for measuring urban noise pollution in large scale participatory sensing campaigns
Résumé
The study reports on the relevancy and accuracy of using mobile phones in participatory noise pollution
monitoring studies in an urban context. During one year, 60 participants used the same smartphone
model to measure environmental noise at 28 different locations in Paris. All measurements were performed
with the same calibrated application. The sound pressure level was recorded from the microphone
every second during a 10-min period. The participants frequently measured the evolution of the
sound level near two standard monitoring sound stations (in a square and near a boulevard), which
enables the assessment of the accuracy and relevancy of collected acoustic measurements. The instantaneous
A-weighting sound level, energy indicators such as LA,eq, LA10, LA50 or LA90 and event indicators such
as the number of noise events exceeding a certain threshold La (NNELPLa) were measured and compared
with reference measurements. The results show that instantaneous sound levels measured with
mobile phones correlate very well (r > 0.9, p < 0.05) with sound levels measured with a class 1 reference
sound level meter with a root mean square error smaller than 3 dB(A). About 10% of the measurements
for the boulevard location (respectively 20% for the square) were inaccurate (r < 0.3, p < 0.05).
Nevertheless, mobile phone measurements are in agreement for the LA50 and the LA90 acoustic indicators
with the fixed station (4-m high) measurements, with a median deviation smaller than 1.5 dB(A) for the
boulevard (respectively 3 dB(A) for the square).