Reducing Urban Noise Pollution: Strategies For Quieter Cities

Noise pollution is a serious issue in cities, with road traffic being the primary source. It can cause a range of problems for residents, including discomfort, disturbed sleep, and adverse effects on mental and physical health. To reduce noise pollution, cities can implement various measures such as sound barriers, noise-reducing road surfaces, electric vehicles, and vegetation alongside roads. Individuals can also play a part by keeping noise levels low, using noise-canceling devices, and being considerate of others.

Vegetation surrounding roads

Natural vegetation, if high enough, wide enough, and dense enough, can effectively decrease road traffic noise. The density of leaves and the thickness of the vegetation play a crucial role in noise reduction. Reports have shown that the noise-screening effect of vegetation is usually considered low unless the planting is dense and the belt of vegetation is deep. When effective, noise barriers consisting of vegetation have been reported to reduce noise levels by 10-15 dB.

The type of vegetation also matters. For example, coniferous plants that do not lose their leaves during the cold season are preferable to deciduous trees, as they provide consistent noise reduction throughout the year. Additionally, trees and bushes with waxy and/or hairy leaf surfaces are better at removing particulates from the air compared to those with smooth leaves.

When implementing roadside vegetation, it is essential to consider the maintenance required to keep the vegetation healthy and effective as a noise barrier. This includes watering, fertilization, trimming, and overall plant care. It is also crucial to ensure that the vegetation does not obstruct drivers' lines of sight or create safety hazards.

In conclusion, vegetation surrounding roads can significantly reduce noise pollution in cities. By choosing the right types of plants and ensuring proper maintenance, this method can provide both functional and aesthetic benefits to urban areas.

Noise barriers/soundwalls

Noise barriers, also known as soundwalls, noise walls, sound berms, acoustical barriers, or acoustic walls, are exterior structures designed to reduce noise pollution from roads, railways, and industrial sources. They are particularly effective at mitigating roadway noise, which is the main source of noise pollution in Europe, according to the European Environment Agency.

The use of noise barriers to block out high-intensity traffic noise was first tested in the United States in the 1960s and became popular in the 1970s with the introduction of environmental laws. The extensive use of noise barriers in the US began after noise regulations were introduced in the early 1970s.

Noise barriers can be constructed from various materials, including masonry, earthwork (such as earth berms), steel, concrete, wood, plastics, insulating wool, composites, or even active materials such as solar photovoltaic panels. The choice of material will determine how sound is mitigated. Walls made of absorptive material, for example, will reduce sound differently from hard, reflective surfaces like masonry or concrete.

One advantage of noise barriers is that they can be effective tools for noise pollution abatement. However, they may not be suitable for all locations and topographies. Other considerations include cost and aesthetics. Additionally, noise barriers can create blocked vision for motorists and rail passengers, and they may become targets for graffiti and vandalism.

One innovative type of noise barrier is the sound-diffracting wall, which bends sound waves and directs them away from homes. These walls have grooves of varying depths, reducing horizontal noise by bending it upwards in the vertical direction. This allows for the use of smaller barriers to deflect more noise away from surrounding residents.

Quiet asphalt

There are several types of quiet asphalt being developed and implemented worldwide. One type is the single-layer porous asphalt, which has been adopted in the Netherlands, France, and Germany. This mix consists of a 30 to 40 mm thick gap-graded mix with 20 to 30 percent air voids, providing a 3 to 5 dBA noise reduction. While this type of mix is more expensive than conventional dense-graded asphalt, it typically lasts 8 to 10 years.

Another type is the two-layer porous asphalt, which has been implemented in Denmark, France, Italy, and is being developed in the Netherlands. This system uses two layers of aggregate mix, with the top layer acting as a filter and the lower layer providing drainage. The two-layer system offers a more significant noise reduction of 8 or 9 dBA compared to conventional asphalt mixes. It also lasts longer, with a pavement life of 8 to 10 years, and is more cost-effective than constructing sound barriers.

The key to the effectiveness of quiet asphalt lies in its ability to absorb sound. Generally, increasing the air voids within an asphalt pavement reduces the noise level. The open-graded or porous nature of quiet asphalt allows it to absorb more sound energy, resulting in reduced noise levels. Additionally, the use of rubber-modified mixes, such as asphalt rubber friction courses, can further enhance noise reduction.

The benefits of quiet asphalt go beyond just noise reduction. It also improves skid resistance, reduces vehicle spray on wet surfaces, enhances drainage, increases durability, and improves resistance to cracking. The smoother surface of quiet asphalt can also provide a more comfortable ride for vehicles, reducing the impact of friction on tires.

While quiet asphalt shows promising results, there are some considerations to be made. One challenge is the public acceptance of quiet pavement as a substitute for other noise mitigation tools. Additionally, policy changes may be required to include quiet pavements in noise abatement strategies. Despite these challenges, quiet asphalt presents a viable option for reducing noise pollution in cities, improving the quality of life for residents.

Electric vehicles

The benefits of adopting EVs go beyond just noise reduction. Firstly, they improve public health by lowering stress levels, enhancing sleep quality, and reducing the risk of cardiovascular problems and mental health issues associated with chronic noise exposure. Secondly, EVs create enhanced urban livability, providing a more tranquil and enjoyable environment for residents in parks, public spaces, and residential areas, fostering a stronger sense of community. Thirdly, quieter cities are more attractive for businesses, tourism, and real estate development, increasing property values and contributing to urban revitalisation efforts. Finally, the adoption of EVs aligns with sustainable and eco-friendly practices, helping to mitigate climate change and improve air quality.

To maximise the potential of EVs in reducing noise pollution, policymakers and city planners should implement incentives for EV adoption, such as financial incentives and rebates. Additionally, planning for robust and well-distributed charging infrastructure is crucial to support the widespread adoption of EVs. Furthermore, addressing challenges related to pedestrian safety, especially for visually impaired individuals, is essential. This can be achieved by adding external sound emitters, known as Acoustic Vehicle Alerting Systems (AVAS), to alert pedestrians of approaching EVs. Public awareness and education campaigns about the benefits of quieter cities and the role of EVs are also important to facilitate this transformative shift.

The transition to electric vehicles and fleet electrification is a promising solution to the problem of noise pollution in cities, offering a quieter and more environmentally friendly future for urban residents.

Sound-friendly furniture

One example of sound-friendly furniture is the INTO the Nordic Silence concept. Their furniture solutions include POD rooms, semi-open workstations, and couches that allow people to hold conversations without being overheard. A study by architect-acoustics consultant Alpo Halme found that these designs dramatically cut down noise, achieving near-total silence in POD spaces and effectively blocking sound in semi-open areas.

Sound-absorbing furniture can take many forms, including room dividers, architectural systems, wall systems, flooring systems, ceiling systems, table systems, and objects. These pieces can be strategically placed in a space to reduce noise levels and create a more pleasant acoustic environment.

In addition to furniture, other sound-absorbing elements can be incorporated into a space, such as acoustic paneling, soundproof curtains, and noise-absorbent materials in machinery and vehicles. These solutions, combined with sound-friendly furniture, can help mitigate the negative health effects of noise pollution, which can include stress, fatigue, sleep disturbances, and increased blood pressure.

By implementing sound-friendly furniture and other noise-reducing measures, cities can work towards creating healthier and more comfortable environments for their residents and visitors.

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