Nonlinear prediction model of noise reduction by greenbelts

Based on the noise-reduction mechanism of greenbelts, a noise-reduction model of greenbelts is proposed along with their sound-propagation characteristics. Two Populus tomentosa greenbelts suitable for noise experiments were selected. A noise-reduction prediction model was established for P. tomentosa. The parameters for this model were the distances between the measuring point and the sound source and the frequencies of the sound source. The model error was 4.1 dB, approximately 9.8% of the average noise attenuation. When the noise frequency was 500 Hz (frequency equivalent to the road traffic noise), the average error was minimized. The experimental method and the model may be extended to noise reduction studies for other greenbelts and used to provide guidelines for road greenbelt construction.