The Influence On The Acoustic Environment Of The Street Building By The Green Belts

The green belt can not only reduce traffic noise pollution, but also purify the air incities, improve the image of the city. Paper from the perspective of ecological noise withartificial recorded analog noise, road forest and hedges on traffic noise attenuation thataffect the green belt sound insulation noise factors, and proposed use of green belt toreduce traffic noise pollution optimize the design. Paper the main conclusions are asfollows:Firstly, taking two typical streets in Chongqing City as examples, their acousticenvironments were evaluated through two methods: objective monitoring andsubjective questionnaire survey. Meanwhile, the personnel comparative effects of trafficnoise to the people in the street shops and residential buildings. Then, with the help ofthe artificial noise source recording, the attenuation effects on the traffic noise of theroad belts and three typical hedgerows (Photinia, the lobular boxwood and cedar) wereresearched. Finally, the noise reduction optimizational designs of the road landscapewere proposed based on the noise reduction features of green belt. The mainconclusions in this paper are as follows:1) The noise pollution of the San Yang Road and the Sha Nanjie Street is serious ofthe daytime: the traffic noise value is higher and the equivalent continuous soundpressure level74dB above at7:00-9:00and17:00-18:30; At13:30-14:30, the trafficnoise value is lower by71.5dB. They are higher than70dB——the daytime noise levelof acoustic environmental quality standards required;2) It is shows that there are44%of the first class respondents(street housingresidents) who think the traffic noise pollution is the first source of pollution, followedby indoor thermal environmental impact, accounting for41%; while there are78%ofthe second class respondents(staff in street shops) who think the traffic noise pollution isthe first source of pollution, followed by indoor air pollution, accounting for13%;3) The effect of the forest noise reduction depends on some factors such asvisibility, width and foliage characteristics. Experimental studies have shown that whenusing the width of40m forest to reduce noise, the total attenuation and insertionattenuation of the poor visibility shrub forest is respectively17.6dB and4.8dB, but thehigh visibility arbor forest is respectively10.1dB and2.2dB, this indicates that the capabilities and visibility of the forest noise reduction is a negative correlation;4) The total noise attenuation and insertion attenuation of the3types of the forestsA, B, C were positively correlated with the forest width, and the reduction effect of thethree kinds of forests is different with each band noise;5) The effect of the hedges noise reduction depends on the plant species and theform of the hedgerow: the noise attenuation effect of the single plant, cross-planting arebetter than the parallel, the arrangement of the three typical hedge plants’noisereduction capabilities is as follows: Photinia> Buxus microphylla> Cedar;6) The noise attenuation effects of different types of hedges band were different:broad-leaved hedge like Photinia has a good noise reduction on the high frequencynoise(f>2000Hz), needles hedge like the lobular boxwood has a good noise reductionon the frequency noise(500Hz<f<2000Hz), while the coniferous cedar hedges has agood noise reduction on the low frequency noise (f<500Hz). So, coniferous andbroadleaf hedges with proper plantings can improve the whole brand frequency noiseattenuation effectively.