Noise pollution is a localised problem, and that is how many people regard it. But just how localised it can be is often not apparent to residents until a project has been implemented. Until now, it has been difficult for residents to understand or visualise the likely noise impacts from new proposals using the available tools for assessment. But that is about to change. A new tool has been developed by the EPD that will let people zoom in on their flats on a digital three-dimensional (3-D) image and get a 360-degree picture of the noise impacts from development proposals.

The digital 3-D interactive noise assessment tool is part of a general effort by the EPD to broaden people's understanding about noise pollution and the actions needed to minimise adverse noise impacts. In recent years we have also produced a web-based noise education package for the general public and organised a series of seminars and workshops.

Our efforts apply not only to noise receivers, but those who generate noise. Company directors, for example, may not be generating construction noise directly, but they or their company policies often may not take into account the effects their projects have on nearby residents. A new provision under the Noise Control Ordinance came into force in 2004 that makes them liable for noise violations, thus ensuring they look at the broader impacts of their work. Quieter demolition methods have also been successfully tested by the EPD and Housing Authority.

Noises in our daily lives.

This digital 3-D image visualises traffic noise levels in a city.

The community in Hong Kong sometimes has different reactions to barriers built on roads. The public's understanding of the effects of noise barriers has been constrained by the fact that the prevailing assessment tool could only provide two-dimensional maps and information. Sometimes even professionals struggle to understand these documents, not to mention the general public. Now, with 3-D mapping, it is hoped the public's understanding of proposals and the associated noise control measures can be greatly enhanced. This is especially important given that public support is a crucial requirement for major projects.

This digital 3-D image illustrates the impact of traffic noise levels to nearby residential buildings.

3-D mapping was developed by the EPD in 2004 using digital maps available from the Lands Department that show terrain and existing road networks, buildings, enclosures and other features. Proposed projects can be super-imposed on the maps and the noise impacts calculated for each option. These impacts can be illustrated on the facade of each building, using colour coding to indicate the level of noise. For instance, red is used for levels greatly exceeding 70 dB(A) and green for readings well within that limit.

Users can walk, fly or drive through the proposed project, and look at it from every angle, even their own flat. This is a huge improvement in helping people to understand the impact of projects. Previously, project proponents would produce photos that focused on the best angles and obviously could not include every angle for every affected resident. Also, environmental impact assessments would focus only on the worst affected sensitive receivers because of the time and cost involved in transferring information from hard copies of maps onto computers, and calculating the impacts.

		A road erected with noise barriers in 3-D display. About one million people in Hong Kong endure unacceptable levels of traffic noise every day. Most of this comes from existing roads. A programme to pave low-noise surfaces on 72 existing roads deemed suitable was begun in 2003. And in 2004 work began on noise barriers, the first time they have been retrofitted on existing roads. The barriers are being erected along Fanling Highway to ease traffic noise for about 2 000 dwellings in Fanling and Sheung Shui. About three kilometres of barriers will be built, ranging in height from four to seven metres. Traffic noise is expected to be reduced by up to 17 dB(A). The project will cost $139 million and be completed by the end of 2005. Over 30 other roads have also been identified as suitable for retrofitted barriers.

The public can experience 3-D mapping on the EPD website.

Two examples of 3-D mapping have been posted on the EPD website so the public, consultants and project proponents can see how it works. This online accessibility means people can obtain information from the comfort of their homes or offices. By making it easy for the public and decision-makers to visualise the results and likely impacts of proposed projects, and compare the advantages and disadvantages of various options and mitigation measures, the EPD hopes that a more informed dialogue can be pursued on future developments.

An understanding of a different kind is being promoted to Hong Kong's company directors. Noise from construction and commercial and industrial activities has been a long-standing concern. Controls to limit pile driving and other noisy work were introduced in the late 1980s and 1990s and, while many operators have complied with the new requirements, a few have ignored them. Between 1999 and 2001, 51 companies were convicted five times or more, of whom 18 had more than 10 convictions and two had more than 22 convictions. Even the imposition of heavier fines has not made a difference, with more than 70 per cent of offences being repeated offences. Clearly, the fines have failed to have a deterrent effect. It was felt a more pertinent message needed to be sent to companies to encourage them to change their corporate management philosophy regarding environmental compliance.

		An engineer follows a manual to establish traffic noise models on computer. Noise is subjective, so the EPD is constantly trying to enhance stakeholders' understanding of noise and how to reduce it. In 2004, a six-month staff exchange programme with the Highways Department was completed. Officers from both departments got hands-on experience in dealing with the factors at play outside their areas of expertise, such as traffic impacts, engineering constraints and the handling of noise complaints. The EPD was also able to help Highways Department staff develop procedures on establishing traffic noise models.   Noise levels being measured in a domestic flat. The EPD also pushed ahead with a study to help it better understand the levels and impacts of noise in Hong Kong. The study began in December 2003 and is measuring typical noise levels at homes, restaurants, karaoke bars, game centres, concert halls, beaches, barbecue sites, urban parks, country parks and undeveloped areas. It will also evaluate the effectiveness of measures to reduce traffic noise, such as barriers and architectural features. The study will be completed in 2005 and it is hoped the information can be used in formulating new policies and measures to control noise.

Codes of Practice help company directors understand their liability regarding compliance with the Noise Control Ordinance.

Under an amendment passed by the Legislative Council in 2002, company directors can be held liable for repeated noise offences committed by their firm, unless they hold non-executive posts or are not involved in corporate management. The government agreed not to enforce the amendment until Codes of Practice for the construction industry and commercial and industrial operators were devised, explaining how company directors could comply. The Codes were finalised in 2004 and on 8 October, the amendment came into effect.

Directors will be given a warning letter on a first offence, telling them to take steps to avoid future violations or be held liable. If another offence occurs within two years of the letter being issued, the director will be charged. Defendants can put forward a due diligence defence if they demonstrate they have established an environmental management system (EMS) and ensured its effective operation - the first time EMS has been explicitly made a defence in law.

A seminar addresses queries and misunderstandings about directors' liability under the Noise Control Ordinance.

The aim here is not to rely on prosecutions, but to try to prevent violations in the first place. The Codes of Practice have been placed on the EPD webpage and seminars were held in October to answer queries and clarify any misunderstandings, attended by more than 500 people. By increasing directors' awareness of their responsibilities, and pointing them in the right direction, it is hoped the nuisance of noise from construction and other stationary activities can be reduced.

The benefits of encouraging directors to avoid prosecutions and adopt an EMS are much wider than a reduction of noise at specific sites. Environmental management systems encourage operators to aim for the best possible practices, even those that go further than the legal requirement. One example is the hydraulic crusher.

The EPD has been actively promoting the use of quiet construction methods and equipment, particularly with the Housing Authority (HA), which is the biggest residential developer in Hong Kong. The hydraulic crusher can be more than 15 dB(A) quieter than excavator-mounted breakers, which are in common use. The HA has tested the device and found it was effective at reducing noise from demolition works. It has prepared guidelines for the construction industry on hydraulic crushers, and will use them in areas near sensitive receivers. Although the crushing takes longer and costs a little more - adding about five per cent to the cost of a demolition project - the HA accepts this trade-off for a quieter environment (see box).

The importance of the crusher, of company directors' liability, and of public understanding of the noise impacts of major projects must be seen against the broader canvas of Hong Kong's development. A lot of older urban areas will likely be re-developed in the next 20 years. New projects will be built to meet demand for greater integration with our neighbours, and to meet population increases. The choices will never be noise-free. But the EPD believes they can be made more acceptable if everyone understands the consequences, if developers live up to their responsibilities and if the quietest available technologies are used to keep the noise to a minimum.

		The excavator-mounted breakers commonly used to break up concrete in Hong Kong are among the noisiest pieces of construction equipment around, with noise levels reaching 122 dB(A). The EPD has worked with the Housing Authority to promote hydraulic crushers as a quieter alternative - more than 15 dB(A) quieter. These crushers operate as their name says. Instead of striking the concrete in a percussive action, they have large jaws that open and shut, thereby crushing the concrete. The Housing Authority has carried out several trials with crushers and although they increase demolition time by eight to 16 per cent and add about five per cent to the cost, the extra expense is considered worth it. The Housing Authority will use crushers in projects next to sensitive receivers, such as schools and hospitals.     Hydraulic crushers can operate more than 15 dB(A) quieter than excavator-mounted breakers in demolition works.

Promote wider application of the three-dimensional noise assessment tool to enable the public to better understand the noise impacts from proposed development projects and be more engaged in the planning and design stages. Enforce the new provisions of the Noise Control Ordinance holding company directors liable for repeated noise offences. Continue to promote the use of new and quieter technologies for construction work. Continue to assist in the implementation of practicable engineering measures to redress traffic noise from existing roads, including barriers and low noise road surfacing.