Environmental Hong Kong 2003
Environmental Protection Department

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| Hong Kong's Environment | Community Awareness | Partnership | Environmental Assessment and Planning | Air | Noise | Waste | Water | Enforcement |


Noise

 
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Mission

To prevent, minimise and resolve environmental noise problems through intervention in the planning process, implementation of noise abatement measures and enforcement of the Noise Control Ordinance.

A Sound Understanding

In crowded Hong Kong, everybody is inevitably affected by noise. Whether in the home, school or on the street, the roar of traffic, construction noise or noisy air-conditioners is inescapable. The difficulty in Hong Kong is that there is no perfect solution to noise and there are many physical constraints. Many people do not understand these constraints and get frustrated.

Photo - Hong Kong is a crowded and densely developed city

The Environmental Protection Department (EPD) is trying to address the lack of public understanding about the problem. A dedicated noise website and CD-ROM are being created to inform the public about all the issues surrounding noise and explain the efforts to make Hong Kong a quieter place. Noise comes from many different sources, such as construction sites, garages, restaurants, airports and roads. The department hopes to make people more aware of the successes and challenges in tackling this persistent problem, as described below.

The Basics of Noise

Photo - Measuring the impacts of noise

Noise is caused by the vibration of air particles in the atmosphere. It can be measured on a decibel scale. For instance, a jackhammer 10 metres away is about 95 decibels, a diesel freight train 25 metres away is more than 80 decibels, while a soft whisper in a library is about 40 decibels. The government aims to contain road traffic noise in residential areas to 70 decibels and has laid down different limits for other stationary sources. But clearly, noise remains a problem in Hong Kong, despite the efforts and various successes of the past.

Noise pollution usually attracts a large number of complaints, making it one of the most prominent pollution problems. In 2002, there were over 12 000 noise complaints, about half of which concerned noise from domestic neighbours. The rest were mostly against stationary sources, such as construction sites, noisy air-conditioners in commercial complexes or restaurants. In addition, excessive traffic noise continued to affect one million people each day. Excessive traffic noise is caused not only by the occasional loud vehicle that passes by, but also by prolonged loudness. This is measured in L10 (1 hour) to reflect noise nuisance, rather than just the decibel levels of individual vehicles. Noise that exceeds 70 decibels for six minutes in one hour - one-tenth of the time - is considered excessive.

Whether from a stationary source or moving vehicle, noise problems may need complicated solutions. Noise usually cannot be eliminated, only contained or moved out of earshot. The latter happened with airport noise when the old Kai Tak airport, which affected 380 000 residents, was moved to relatively isolated Chek Lap Kok in 1998. But roads and buildings cannot be moved so easily. It is necessary to find other means of protecting residents from the worst excesses of noise.

Controlling Noise

Photo - Noise levels in Kowloon dropped dramatically when the airport moved from Kai Tak to Chek Lap Kok

The main legislation on noise is the Noise Control Ordinance, which was enacted in 1988. It applies largely to stationary sources and construction sites. Restaurants, for example, often have large ventilation and air-conditioning units which can be very noisy. If these are enclosed or fitted with silencers, the noise can be reduced by 6 to 20 decibels. The ordinance gives the EPD the power to issue abatement notices ordering operators to stop the noise or install noise-reducing devices. In 2002, the EPD handled about 6 000 stationary noise complaints and issued 4 000 pieces of advice or warnings, as well as about 160 abatement notices. Many problems were resolved promptly, without the need to issue legal notices or prosecute. If recipients fail to obey warnings or notices, they may face prosecution.

The ordinance also applies to construction noise, which is a bit more complicated to control. Builders can only carry out noisy work, such as pile-driving, during certain hours and they have to use quieter equipment. But violations continue to occur, often at odd times of the day or on public holidays. More worryingly, a number of operators have been repeat offenders. A few years ago, the EPD proposed that corporate directors be held personally liable for repeat noise offences on their construction sites. After extensive consultation with the industry, the proposal was passed by the Legislative Council in June 2002 and will be applied after a code of practice has been issued, hopefully in 2003.

Chart - Number of offenders convicted five times or more under the Noise Control Ordinance between 1999 and 2001

Repeat Offenders

Laws to control noise are well-established, but some offenders, particularly in the construction trade, see the fines they receive as the cost of doing business. Between 1999 and 2001, 51 companies were convicted five times or more of noise violations. Eighteen were convicted more than 10 times. It was felt a stronger deterrent was needed. In June 2002 the Legislative Council passed an amendment to the Noise Control Ordinance, which holds company directors liable for noise offences.

The amendment applies if a second offence or more is committed at the same construction site and if it occurs after directors have received written warning from the EPD. The department will issue that warning after the first offence, to alert management to the problem, then prosecute if the problem persists. There is a two-year time limit to the warning letter. A code of practice is being drafted and the law will be applied after that is issued. At the same time, the EPD is pursuing a partnership programme with the industry to raise awareness and offer general advice and support.


At the same time as creating deterrents, the EPD is also trying to be more helpful. One concern has been that the construction industry and others were not well-informed about how to reduce noise. Partnership programmes therefore have been enhanced over the past three years to raise awareness, offer general advice and share views. The programmes initially are targeted at the construction, restaurant, garage and property management trades. So far they appear to have been effective. Noise prosecutions dropped from a peak of 523 cases in 2001 to 273 cases in 2002.

But while enforcing the ordinance and developing partnerships have helped to reduce noise from stationary sources, a different approach is needed to address traffic noise. Once a busy road has been built next to a residential building, or vice versa, it is very difficult to solve the noise problem. And many busy roads and buildings were built next to each other when Hong Kong was undergoing rapid development in the 1960s, 1970s and 1980s.

Photo - Noise-reducing installation for construction machinery

Photo - EPD staff explained noise control measures at a construction site


Traffic Noise

A total of 650 existing roads in Hong Kong have excessive noise, affecting one million people. There are two obvious solutions: erect barriers or enclosures, or cover the roads with a quieter, absorbent surface. Unfortunately, both measures are hampered by constraints.

Barriers are good at containing noise, but there are several constraints in using them. They require space, they cannot compromise traffic safety and they cannot block vehicle or pedestrian access to buildings, ground floor shops and - most importantly - fire exits. Only about 30 existing roads are considered suitable for barriers, which will be installed progressively.

Photo - A typical noisy traffic route

Photo - Barriers block out noise from receivers


Low-noise surfaces can reduce noise by a few decibels, but they are not suitable on every road. Open-texture pavement is being used to reduce noise on high-speed roads, such as the Island Eastern Corridor, and is now a standard for new highways. Since 1987, 11 kilometres of highways have been resurfaced, benefiting about 16 000 homes. But the application of this pavement on local roads is more difficult. It wears down easily so roads with a lot of heavy traffic, on an incline or with lots of stop-start and turning actions are not considered suitable. Only 72 local roads can be re-surfaced with this material. Work began on the first batch of 24 in 2002. The rest will be resurfaced by the end of 2004, bringing a noise reduction of one to three decibels and benefiting another 40 000 homes.

Low-noise Road Surfaces

The material used for paving roads can contribute to traffic noise. Materials that are too rigid or too flexible are not able to absorb noise and it bounces back into the environment. The EPD has worked with the Highways Department to try and find materials that can help to reduce road noise.

Photo - Low-noise road surfacing on a section of West Kowloon Corridor

Open-texture pavement cuts traffic noise by one to five decibels. It also enhances road-tyre friction and safety through better water drainage during wet weather. The material is now a standard requirement for all high-speed roads where traffic flows over 70 kilometres an hour. The government has also initiated a programme to apply open-texture pavement to existing local roads where possible. Only roads without a lot of heavy vehicles, incline or start-stop actions are suitable, because these types of conditions will significantly affect the pavement's lifespan, creating other problems. Seventy-two existing local roads could meet the requirements and will be resurfaced by 2004. The EPD and Highways Department are also continuing to investigate other noise-reducing road materials.

Photo - A close look of the low-noise road surface showing the open-texture finish


That still leaves many noisy roads unabated. The government is exploring the use of other materials for paving roads that can reduce noise and are durable. It will also report to the Legislative Council in 2003 on a trial of proposed traffic management measures for controlling noise. The trial was carried out earlier on the West Kowloon Corridor and was found to have impacts on other roads. Therefore, in terms of doing something with the roads to reduce traffic noise, no magic bullet solution yet exists.

Photo - Traffic management is being used to restrict access of heavy vehicles to this flyover during the night time to control noise.

Vehicles themselves can be made less noisy, although the sheer volume of traffic and different driving styles mean the impact will be small. Vehicle noise regulations were amended in 2002 to bring them in line with the latest standards in Europe and Japan. The effects will not be felt for some time because it will take several years to replace the existing fleet. But traffic noise is expected to be reduced by one or two decibels through this measure.

Chart - Noise Standards under the Noise Control (Motor Vehicles) Regulation

In situations where it is not possible to reduce noise at source to an acceptable level, insulating the noise receiver is a last resort. The government has insulated more than 10 000 classrooms since 1987. But insulation can only reduce noise when the windows are kept tightly closed and the air-conditioning is running. And people still complain about noise pollution even when their classrooms or buildings are insulated.

In fact, the best solution to traffic noise is the one that cannot apply to existing roads: good planning. The EPD is heavily involved in ensuring that new developments and new roads do not create new, insoluble problems.

There are many examples of how good planning can reduce noise. The integrated planning of Tung Chung New Town, for example, has ensured homes and other sensitive noise receivers are kept at a distance from roads, or are screened by commercial blocks, natural earth bunds and other attractive barriers. The principle of keeping people and noise separated is also applied through the Environmental Impact Assessment Ordinance, which assesses the impacts of new projects to prevent noise problems.

A Need for Understanding

Everybody is affected by noise and everybody wants something done about it. The EPD has an extensive programme but, as described above, it faces constraints in controlling the problem. This is not always understood by the public which, understandably, wants immediate solutions to the annoying problem of noise.

The department is trying to clear up misconceptions and improve understanding through a dedicated noise website http://www.epd.gov.hk/epd/noise_education and CD-ROM, which will be released in 2003. These are targeted at both the general public and children and explain what noise is, what the government is doing to reduce it and what individuals can do to reduce their noise. Noise is a difficult problem to solve because it involves many different sources and factors. Hopefully, greater understanding of the problem - and a commitment by everyone to do what they can to reduce noise - can help to make Hong Kong's noise levels more bearable.

Photo - Good planning has helped to control traffic noise in Tung Chung new town

Photo - The EPD produces publications and pamphlets to inform people about noise

Photo - An education package has been produced on environmental noise

Photo - The EPD's noise website


Reaching Out


A dedicated noise website has been set up by the EPD to help improve the public's understanding about noise. By visiting http://www.epd.gov.hk/epd/noise_education, people can find out what noise is, how humans perceive noise, what the noise problems are in Hong Kong, what the government is doing to control them, how noise is assessed and how noise can be prevented. A CD-ROM version has also been prepared, including a version targeted at primary and secondary students.

One of the interesting features of the package is that it lets people "trying out planning to avoid noise problem". Users can type in different information - such as the height of a building, its distance from the road, traffic speed and percentage of heavy vehicles - and see what the noise levels will be in different flats in the building. The bilingual package was prepared in 2002, for release in early 2003. The CD-ROMs will be distributed to schools and District Offices, and briefing sessions have been organised for teachers to help them understand the package's special features.

Highlights of 2002

Amended the Noise Control Ordinance to deter repeated offences. New provisions hold company directors liable for offences committed by their companies.

Tightened the vehicle noise emission standards to tie in with the latest internationally recognised standards.

Launched a programme to promote community understanding of environmental noise.

Looking Ahead

Explore suitable materials to reduce traffic noise on local roads.

Formulate codes of practice to guide the trade on good management practices.

Enhance partnerships with a variety of industry and trade groups to raise noise awareness and help them improve their environmental performance.

Promote the use of new and quieter technologies for construction works.



| A Sound Understanding | Resource Materials on Noise |