Research project measures air quality and drone noise in Athens

The ImAFUSA research project has been measuring air quality with the use of drones. The project is funded by the Horizon Europe Programme and managed by the SESAR 3 Joint Undertaking initiative. 

Researchers from Delft University Faculty of Aerospace Engineering (TUDelft) participated in the psychoacoustic experiments carried out by the project in May 2024 in Athens by providing the drone equipment, which simultaneously recorded the air quality data, and measuring drone noise. 

The DJI Mavic 3E drone was used for this experiment with the Sniffer 4D air quality sensor as a payload. The microphone array used to measure the sound is the CAE Bionic M-112 array, with 112 microphones, an optical camera, and a tripod. The system has a sampling rate of 48 kHz, and it is placed at a 45-degree angle from the ground to best capture the flight trajectories.

The measurements took place over the full one minute that the participants were listening. To synchronise the clocks from the University of Salford’s recording equipment and those of TU Delft, a clap was performed, so the measurements could be aligned from there. 

The recorded data from these microphones is used in a process called ‘beamforming’ to localise the acoustic source, creating the strength of a source map on top of the recorded optical image. It is also used in more traditional noise metrics such as frequency versus time and sound pressure levels. 

Combined with the responses from the participants, this noise data can provide a direct correlation between these metrics to human annoyance.

Additionally, a B&K Sound Level Meter was used to capture the precise sound metrics necessary for psychoacoustic analysis. These metrics were recorded across the full minute in which the participants were observing the noise.

Air quality measurements were carried out throughout the drone flights to record the local air quality across the park, creating a 3D map of the concentrations. Due to the presence of a busy road nearby, higher air pollutant concentrations were obtained near this area. The measurements will be compared to air quality measurements taken in February to see how the concentrations change throughout the year.