Appendix

EIA Study Brief No. ESB-102/2002

May 2002

Environmental Impact Assessment Ordinance (Cap. 499), Section 5 (7)

Environmental Impact Assessment Study Brief No. ESB-102/2002

Project Title : Reprovisioning of Diamond Hill Crematorium

Name of Applicant: Architectural Services Department

(hereinafter known as the "Applicant")

1. BACKGROUND

1.1 An application (No. ESB-102/2002) for an Environmental Impact Assessment (EIA) study brief under section 5(1) of the Environmental Impact Assessment Ordinance (EIAO) was submitted by the captioned Applicant on 25^th March 2002 with a Project Profile (No. PP-166/2002).

1.2 The Applicant proposes to construct a new crematorium of 6 cremators with total capacity of 1,260 kg per hour to replace the existing 6 cremators (hereinafter referred as the Project). The location of the Project is shown in Figure No. 1 in the Project Profile. The Project also includes the provision of a full range of ancillary facilities required for the operation of a crematorium, including:

(a) air pollution control systems to control the emission of the cremators

(b) four service halls

(d) emergency generator room

(e) underground fuel tanks

(f) mortuary

(g) office accommodation

(h) store rooms and dangerous goods store

(i) public toilets

(j) parking spaces for coaches and private cars

(k) refuse storage chambers

(l) garden of remembrance

1.3 Pursuant to section 5(7)(a) of the EIAO, the Director of Environmental Protection (the Director) issues this EIA study brief to the Applicant to carry out an EIA study for the Project.

1.4 The purpose of this EIA study is to provide information on the nature and extent of environmental impacts arising from the construction and operation of the proposed project and related activities taking place concurrently. This information will contribute to decisions by the Director on:

(i) the overall acceptability of any adverse environmental consequences that are likely to arise as a result of the proposed project;

(ii) the conditions and requirements for the detailed design, construction and operation of the proposed project to mitigate against adverse environmental consequences wherever practicable; and

(iii) acceptability of residual impacts after proposed mitigation measures are implemented.

2. OBJECTIVES OF THE EIA STUDY

2.1 The objectives of the EIA study are as follows:

(i) to describe the proposed project together with the requirements for carrying out the proposed project;

(ii) to identify and describe elements of community and environment likely to be affected by the proposed project and/or likely to cause adverse impacts to the proposed project, including natural and man-made environment and the associated environmental constraints;

(iii) to describe the considerations given in selecting the proposed site, layout, design (including technology to be adopted for the new cremators), and construction method; to provide reasons for selecting the preferred option and to describe the part environmental factors played in the selection process;

(iv) to identify and quantify emission sources and determine the significance of impacts on sensitive receivers and potentially affected uses;

(v) to identify and quantify waste management requirements and propose measures to mitigate or prevent impacts, and measures to be adopted to avoid introducing land contamination at the new cremators’ site;

(vi) to identify and quantify any potential visual impacts and to propose measures to mitigate impacts;

(vii) to identify the negative impacts and propose the provision mitigation measures so as to minimize pollution, environmental disturbance and nuisance during construction and operation of the project;

(viii) to identify, predict and evaluate the residual (i.e. after practicable mitigation) environmental impacts and the cumulative effects expected to arise during the construction and operation phases of the proposed project in relation to the sensitive receivers and potential affected uses;

(ix) to identify, assess and specify methods, measures and standards, to be included in the detailed design, construction and operation of the proposed project which are necessary to mitigate these environmental impacts and cumulative effects and reduce them to acceptable levels;

(x) to identify constraints associated with the mitigation measures recommended in the EIA study; and

(xi) to design and specify an environmental monitoring program, and if required, other environmental monitoring and audit requirements, to ensure the implementation and the effectiveness of the recommended environmental protection and pollution control measures.

3. DETAILED REQUIREMENTS OF THE EIA STUDY

3.1 The purpose of this study brief is to scope the key issues of the EIA study. The Applicant has to demonstrate in the EIA report that the criteria in the relevant sections of the Technical Memorandum on the Environmental Impact Assessment Process of the Environmental Impact Assessment Ordinance (hereinafter referred to as the TM) are fully complied with.

3.2 The Scope

3.2.1 The scope of this EIA study shall cover the project proposed in the Project Profile and shall include the works and facilities mentioned in section 1.2 above. Figure 1 of this Study Brief shows the location of the new and existing crematoriums. The EIA study shall address the likely key issues described below, together with any key issues identified during the course of the study and the cumulative environmental impacts of the Project, through interaction or in combination with other existing, committed and planned developments in the vicinity of the Project:

(i) the consideration given in selecting the proposed site, layout, design (including technology to be adopted for the new cremators), and construction method for the Project;

(ii) the air quality impacts arising from the construction and operation of the Project;

(iii) the measures to be adopted to avoid introducing land contamination at the new cremators’ site, as well as the waste management for the construction and operation of the Project;

(iv) the visual impacts from the construction and operation of the Project;

(v) the safety requirements related to storage of fuel;

(vi) the construction and operational noise impacts of the Project; and,

(vii) handling of any effluent discharge from the air pollution control/scrubbing systems for the new crematorium during operation stage;.

3.2.2 The Applicant shall also assess all the environmental impacts during the transitional stage of the Project before the existing cremators cease operation, scenarios to include test runs of the new cremators concurrently with the existing cremators remain operative in full service.

3.3.3 Regarding the potential cumulative impacts, other projects under planning to be considered to include, but not necessarily limited to, the construction stage impacts due to the proposed Diamond Hill No. 2 Fresh Water Service Reservoir and any potential developments on the cleared land along Po Kong Village Road near the Project’s site.

3.3 Decommissioning of the Existing Diamond Hill Crematorium

3.3.1 Section 4.2 of the Project Profile stated that the existing Diamond Hill Crematorium will be decommissioned when the proposed new crematorium is in operation. However, section 1.2 of the Project Profile on the project scope only listed out those work items related to the new cremators but did not mention the decommissioning of the existing cremators. The Applicant shall state clearly whether or not the decommissioning of the existing cremators is covered under the EIA Study.

3.3.2 If the Applicant confirms that environmental impacts of the decommissioning and demolition of the existing cremators is covered in the EIA Study, the Applicant shall also address in the EIA the issues stated in Appendix A to this Study Brief related to the decommissioning element.

3.3.3 If the Applicant confirms that environmental impacts of the decommissioning and demolition of the existing cremators is not covered in the EIA Study, the Applicant shall provide information on the future plan on the existing cremators, including any plan on the assessment of the environmental impacts of the decommissioning project.

3.4 Description of Siting, Layout, Design and Construction Methods Considered

3.4.1 The existing operation of the Diamond Hill Crematorium which is located in the urban area surrounded by many residential developments is of concern to the public. There have been environmental complaints against the smoke and odour emissions from the cremators. In addition, several schools located close to the Crematorium are currently under construction.

3.4.2 Given the general public’s concerns on the existing location of the Crematorium, while the Project Profile stated that the Project would provide cremators of advance technology, the Applicant shall state the justifications for continually using the proposed site for the reprovisioning proposal.

3.4.3 The Applicant shall also describe the consideration given to other possible layout(s) within the proposed site, available technology options for the new cremators, and alternative construction method to minimise excessive nuisances during the construction stage of the Project. In particular, such considerations should cover the potential environmental impacts to nearby existing and planned sensitive receivers when different layout, technology or construction method are used. The Applicant shall state the justifications for the selecting the proposed layout, technology and construction method.

Technical Requirements

3.5 The Applicant shall conduct the EIA study to address all environmental aspects of the works and activities as described in the scope as set out above.

3.6 The EIA study shall include the following technical requirements on specific impacts.

3.6.1 Air Quality Impact

3.6.1.1 The Applicant shall follow the criteria and guidelines for evaluating and assessing air quality impact as stated in section 1 of Annex 4 and Annex 12 of the TM respectively.

3.6.1.2 The assessment area for air quality impact shall be defined by a distance of 500 m from the boundary of the project site, yet it may be extended depending on the circumstances and the scale of the project.

3.6.1.3 The Applicant shall assess the air pollutant concentrations making reference to the relevant sections of the air modelling guideline in Appendices B-1 to B-4 to this EIA Study Brief, or other methodology as agreed by the Director. The Applicant shall make reference to the Guidelines with respect to construction dust impacts, cumulative construction dust impact and stack emissions evaluation. In consideration of construction dust impact, the Applicant shall make reference to the Fugitive Dust Model (FDM) in Appendixes B-1 and B-3; in consideration of cumulative construction dust impact, the Applicant shall make reference to the FDM in Appendixes B-1, B-2 and B-3; in consideration of stack emissions evaluation, the Applicant shall make reference to the Industrial Source Complex Dispersion Model (ISCST3) in Appendixes B-1 and B-4.

3.6.1.4 The air quality assessment shall cover the construction and operation of the Project, and include the following:

Background and analysis of activities

(i) Provide background information relating to air quality issues relevant to the project, e.g. description of the types of activities during construction stage of the project such as site clearance, excavation, material handling and wind erosion that will likely give rise to dust emissions and those activities during operation stage of the project such as operation of the cremators that will give off gaseous emissions.

(ii) Give an account, where appropriate, of the consideration/measures that had been taken into consideration in the planning of the project to abate the air pollution impact. That is, the Applicant should state the considerations given to the use of various potential construction methods/phasing programmes and cremator technologies and modes of operation to minimise the constructional and operational air quality impact respectively. For example, consideration should be given to the use of gaseous fuel to reduce emissions during cremation.

(iii) Present the background air quality levels in the assessment area for the purpose of evaluating the cumulative constructional and operational air quality impacts. Also compare and present the anticipated improvements over the existing level in terms of air emission data.

Identification of ASRs and examination of emission/dispersion characteristics

(iv) Identify and describe representative existing and planned/committed air sensitive receivers (ASRs) that would likely be affected by the project, including those earmarked on the relevant Outline Zoning Plans, Development Permission Area Plans, Outline Development Plans and Layout Plans. The Applicant shall select the assessment points of the identified ASRs such that they represent the worst impact point of these ASRs. A map showing the location and a description including the name of the buildings, their uses and height of the selected assessment points shall be given. The separation distances of these ASRs from the nearest emission sources should also be given. Please also note that the proposed Diamond Hill No. 2 Fresh Water Service Reservoir has been planned for construction in the near future and would be about 150 meters from the proposed new crematorium.

(v) Provide an exhaustive list of air pollutant emission sources, including any nearby emission sources which are likely to have impact on the project based on the analysis of the constructional and operational activities of the project in (i) above. Examples of constructional stage emission sources include stock piling, concrete batching, etc. Examples of operational stage emission sources include cremators, any nearby industrial source, etc. Confirmation of the validity of the assumptions and the magnitude of the activities (e.g. volume of construction materials handled etc.) shall be obtained from the relevant government department/authorities and documented.

Constructional air quality impact

(vi) The Applicant shall follow the requirements of the Air Pollution Control (Construction Dust) Regulation in dust control to ensure construction dust impacts are controlled within the relevant standards as stipulated in section 1 of Annex 4 of the TM. An audit and monitoring program during constructional stage shall be initiated to verify the effectiveness of the control measures and to ensure that the construction dust levels be brought under control.

(vii) If the Applicant anticipates a significant construction dust impact that will likely cause exceedance of the recommended limits in the TM at the ASRs despite incorporation of the dust control measures stated in (vi) above, a quantitative assessment should be carried out to evaluate the construction dust impact at the identified ASRs based on the emission strength of the emission sources identified in (v) above. The Applicant shall follow (x) to (xiii) below when carrying out the quantitative assessment.

Operational air quality impact

(viii) In addition to preparing a list of emission sources required in (v) above, the Applicant shall state the target emission levels for the cremators, and compare them with the standards specified in the latest set of Guidance Note on the Best Practicable Means for Crematoria issued by the Air Management Group of EPD, and other relevant overseas standards. The target emission levels, including but not limited to that for dioxin, should be agreed with the Director prior to the carrying out of the quantitative assessment on operational air quality impact.

(ix) The Applicant shall calculate the expected air pollutant concentrations at the identified ASRs. Calculations for the expected impact shall be based on an assumed reasonably worst case scenario under normal operating conditions and during the testing stage of the new cremators. Special attention shall be placed on the testing stage of the new cremators when there is potential for both the existing and new cremators being operated and emitting air pollutants concurrently. The evaluation shall be based on the strength of the emission sources identified in (v) and (viii) above. The Applicant shall follow (x) to (xiii) below when carrying out the quantitative assessment.

Quantitative Assessment Methodology

(x) The Applicant shall apply the general principles, where applicable, enunciated in the modeling guidelines in Appendices B1 to B-4 while making allowance for the specific characteristic of the Project. This specific methodology must be documented in such level of details (preferably with tables and diagrams) to allow the readers of the assessment report to grasp how the model is set up to simulate the situation at hand without referring to the model input files. Details of the calculation of the emission rates of air pollutants and a map showing the emission sources and the identified ASRs for input to the modeling shall be presented in the report. The Applicant must ensure consistency between the text description and the model files at every stage of submission. In case of doubt, prior agreement between the Applicant and the Director on the specific modelling details should be sought.

(xi) The Applicant shall identify the key/representative air pollutant parameters (types of pollutants and the averaging time concentration) to be evaluated and provide explanation for choosing these parameters for the assessment of the impact of the project. Among the identified parameters, emissions such as toxic air pollutants (including but not limited to dioxins) and odour (if any) shall be included.

(xii) The Applicant shall calculate the cumulative air quality impact at the identified ASRs and compare these results against the criteria set out in section 1 of Annex 4 in the TM. The predicted air quality impacts (both unmitigated and mitigated) shall be presented in the form of summary table and pollution contours, for comparison with relevant air quality standards and examination of the land use implications of these impacts. Plans of suitable scale should be used for presentation of pollution contour for determining buffer distances required. In order to get a full picture of air emissions in particular dioxins from the proposed Project, an inventory figure (in g I-TEQ/year) should be estimated and presented.

Mitigating measures for non-compliance

(xiii) The Applicant shall propose remedies and mitigating measures where the predicted air quality impact exceeds the criteria set in section 1 of Annex 4 in the TM. These measures and any constraints on future land use planning shall be agreed with the relevant government departments/authorities and documented. The Applicant shall demonstrate quantitatively that the resultant impacts after incorporation of the proposed mitigating measures will comply with the criteria stipulated in section 1 of Annex 4 in the TM.

Submission of model files

(xiv) All input and output file(s) of the model run(s) shall be submitted to the Director in electronic format.

3.6.2 Land Contamination Impact & Waste Management

Land Contamination Prevention

3.6.2.1To prevent contamination problems from arising in future, the Applicant shall:

(i) identify the possible sources of contamination, including but not limited to dioxin, in their operations; and

(ii) formulate appropriate operational practices, waste management strategies and precautionary measures for prevention of contamination problems.

Waste Management Implications

3.6.2.2 The Applicant shall follow the criteria and guidelines for evaluating and assessing waste management implications as stated in Annexes 7 and 15 of the TM, respectively.

3.6.2.3 The assessment of waste management implications shall cover the following:

(i) Analysis of Activities and Waste Generation

(a) The Applicant shall identify the quantity, quality and timing of the waste arising as a result of the construction and operation activities, based on the sequence and duration of these activities.

(ii) Proposal for Waste Management

(a) Prior to considering the disposal options for various types of wastes, opportunities for reducing waste generation and on-site or off-site re-use shall be fully evaluated. Measures which can be taken in the planning and design stages e.g. by modifying the design approach and in the construction stage for maximising waste reduction shall be separately considered.

(b) Having taken into account all the opportunities for reducing waste generation and maximising reuse, the types and quantities of the wastes required to be disposed of as a consequence shall be estimated and the disposal options for each type of waste described in detail. The disposal method recommended for each type of wastes shall take into account of the result of the assessment in section (c) below.

(c) The impact caused by handling (including labeling, packaging & storage), collection, and disposal of wastes shall be addressed in detail and appropriate mitigation measures proposed. This assessment shall cover the following areas:

(i) potential hazard;

(ii) air & odour emission;

(iii) noise;

(iv) wastewater discharge;

(v) public transport.

3.6.3 Visual Impact

3.6.3.1 The Applicant shall follow the criteria and guidelines for evaluating and assessing visual impact as stated in section 1 of Annex 10 and in Annex 18 of the TM, respectively. The assessment shall also cover all items classified as Designated Projects under Schedule 2 of the EIAO. Both construction and operational impacts shall be assessed. In particular, the transition stage where both the existing and new crematoriums co-exist shall be covered.

3.6.3.2 The assessment area for the visual impact assessment shall be defined by the visual envelope of the project.

3.6.3.3 The Applicant shall review relevant outline development plans, outline zoning plans, layout plans, other published land use plans, planning briefs, studies and guidelines on landscape framework, urban design concept, designated view corridors, open space network and landscape links that may affect the appreciation of the project. The aim is to gain an insight to the future outlook of the area affected so as to assess whether the project can fit into surrounding setting. Any conflict with published land use plan(s) should be highlighted and appropriate follow-up action should be recommended.

3.6.3.4 The Applicant shall assess the visual impacts of the proposed development. In particular, the cumulative visual impacts of the existing and proposed crematorium shall be assessed and taken into account in the formulation of mitigation measures and the assessment of residual impacts. As some nearby sensitive receivers have direct line of sight to the site, mitigation measures such as proper landscape screening shall be provided. The visual impact assessment shall include the following:

(i) identification and plotting of visual envelope of the project within the assessment area;

(ii) identification of the key groups of sensitive receivers within the visual envelope and their views at both ground level and elevated vantage points;

(iii) description of the visual compatibility of the project with the surrounding, and the planned setting and its obstruction and interference with the key views of the adjacent areas; and

(iv) the severity of visual impacts in terms of nature, distance and number of sensitive receivers. The visual impacts of the project with and without mitigation measures shall also be included so as to demonstrate the effectiveness of the proposed mitigation measures.

3.6.3.5 Alternative layout, design and construction method that would avoid or reduce the identified visual impacts shall be evaluated for comparison before adopting other mitigation or compensatory measures to alleviate the impacts. The mitigation measures proposed shall not only be concerned with damage reduction but should also include consideration of potential enhancement of existing visual quality. The Applicant shall recommend mitigation measures to minimise the adverse effects identified above, including provision of a landscape design.

3.6.3.6 The mitigation measures shall include provision of screen planting, revegatation of disturbed land, compensatory planting, provisioning of amenity areas, design of structures, provision of finishes to structures, colour scheme and texture of material used and any measures to mitigate the impacts on existing land use. Parties shall be identified for the on going management and maintenance of the proposed mitigation works to ensure their effectiveness throughout the operation phase of the project. A practical programme and funding proposal for the implementation of the recommended measures shall be provided.

3.6.3.7 Annotated illustration materials such as coloured perspective drawings, plans and section/elevation diagrams, photographs taken at vantage points, and computer-generated photomontage shall be adopted to fully illustrate the visual impacts of the project to the satisfaction of the Director. The Applicant shall record the technical details in preparing the illustration that may need to be submitted for verification of accuracy of the illustrations.

3.6.4 Hazard to Life

The Applicant shall state the fuel for cremation process of the Project. If fuel gas is used, the Applicant shall confirm that it is provided by direct fuel gas pipeline and there will be no on-site storage of the fuel gas. For other non-fuel gas dangerous goods (DG) defined in the Dangerous Goods Ordinance (Cap. 295) but not covered by the Gas Safety Ordinance (Cap. 51), the Applicant shall confirm that the storage quantity would be similar to that in the existing crematorium or petrol filling stations and that the storage will comply with FSD’s safety requirements.

3.6.5 Noise Impact

3.6.5.1 The Applicant shall follow the criteria and guidelines for evaluating and assessing noise impact as stated in Annexes 5 and 13 of the TM respectively.

3.6.5.2 The noise impact assessment shall include the followings:

(i) Determination of Assessment Area

The noise impact assessment shall include all areas within 300m from the project boundary. Subject to the agreement of the Director, the assessment area could be reduced accordingly if the first layer of noise sensitive receivers, closer than 300m from the project boundary, provides acoustic shielding to those receivers located further away.

(ii) Provision of Background Information

The Applicant shall provide all background information relevant to the project including relevant previous and current studies. Unless involved in the planning standards, no existing noise levels are particularly required.

(iii) Identification of Noise Sensitive Receivers

(a) The Applicant shall refer to Annex 13 of the TM when identifying the noise sensitive receivers (NSRs). The NSRs shall include all existing ones and all planned or committed noise sensitive developments and uses earmarked on the relevant Outline Zoning Plans, Outline Development Plans and Layout Plans.

(b) The Applicant shall select assessment points to represent all identified NSRs for carrying out quantitative noise assessment described below. The assessment points shall be agreed with the Director prior to the quantitative noise assessment. A map showing the location and description including name of building, use, and floors of each and every selected assessment point shall be given.

(iv) Provision of an Emission Inventory of the Noise Sources

The Applicant shall provide an inventory of noise sources including construction equipment for construction and demolition noise assessment and fixed plant equipment for operational noise assessment. Confirmation of the validity of the inventory shall be obtained from the relevant government departments/authorities.

(v) Construction / Demolishing Noise Assessment

(a) The Applicant shall carry out assessment of noise impact from construction (excluding percussive piling) of the project during day time, i.e. 7 a.m. to 7 p.m., on weekdays other than general holidays in accordance with the methodology stipulated in paragraphs 5.3. and 5.4 of Annex 13 of the TM. The criteria in Table 1B of Annex 5 of the TM shall be adopted in the assessment.

(b) To minimize the construction noise impact, alternative construction methods to replace percussive piling shall be proposed as far as practicable.

(c) If the unmitigated construction noise levels are found to exceed the relevant criteria, the Applicant shall propose practicable direct mitigation measures (including movable barriers, enclosures, quieter alternative methods, re-scheduling and restricting hours of operation of noisy task(s) to minimize the impact. If the mitigated noise levels still exceed the relevant criteria, the duration of the noise exceedance shall be given.

(d) In case the Applicant would like to evaluate whether construction works in restricted hours as defined under the Noise Control Ordinance (NCO) are feasible or not in the context of programming construction works, reference should be made to the relevant technical memoranda issued under the NCO. Regardless of the results of construction noise impact assessment for restricted hours, the Noise Control Authority will consider a well-justified Construction Noise Permit (CNP) application, once filed, based on the NCO, the relevant technical memoranda issued under the NCO, and the contemporary condition/situations of adjoining land uses and any previous complaints against construction activities at the site before making his decision in granting a CNP. This aspect should be explicitly stated in the noise chapter and the conclusions and recommendations chapter in the EIA report.

(vi) Operational Noise

(a) The Applicant shall analyze the scope of the proposed system to identify noise sources for the purpose of noise impact assessment.

(b) The Applicant shall calculate the expected noise using standard acoustic principles. Calculations for the expected noise shall be based on assumed plant inventories and utilization schedule for the worst case scenario. The Applicant shall calculate the noise levels taking into account of correction of tonality, impulsiveness and intermittency in accordance with the Technical Memorandum for the Assessment of Noise from Places other than Domestic Premises, Public Places or Construction Sites.

(c) The Applicant shall present the existing and future noise levels in Leq (30 mins) at the NSRs at various representative floor levels (in mPD) on tables and plans of suitable scales. Quantitative assessment at the NSRs for proposed fixed noise source(s) shall be carried out and compared against the criteria set out in Table 1A of Annex 5 of the TM.

(d) Proposals for Noise Mitigation Measures

The Applicant shall propose direct technical remedies in all situations where the predicted noise level exceeds the criteria set out in Table 1A of Annex 5 of the TM to protect the affected NSRs. Specific reasons for not adopting certain direct technical remedies in the design to reduce the noise to a level meeting the criteria in the TM or to maximize the protection for the NSRs should be clearly quantified and laid down. The total number of dwellings and other noise sensitive element that will be benefited by the provision of direct technical remedies should be provided.

The total number of dwellings and other noise sensitive elements that will still be exposed to noise above the criteria with the implementation of all recommended direct technical remedies shall be quantified.

In case where a number of the NSRs cannot all be protected by the recommended direct technical remedies, the Applicant shall consider alternatives to reduce the impacts.

(vii) Assessment of Side Effects and Constraints

The Applicant shall identify, assess and propose means to minimize any side effects and to resolve any potential constraints arising from the inclusion of any recommended direct technical remedies.

3.6.6 Water Quality

The Applicant shall provide a general description of any air pollution control system and any scrubbing system for the new cremators, and confirm that there will be no effluent discharge from the new cremators or any associated air pollution control/scrubbing system, nor increase in sewage load due to the reprovisioning proposal. Otherwise, the Applicant shall demonstrate that there would be no adverse impact due to the effluent discharges, including an assessment on the discharges on the sewerage system downstream of the Project area and propose mitigation measures, if required.

3.6.7 Summary of Environmental Outcomes

3.6.7.1 The EIA report shall contain a summary of the key environmental outcomes arising from the EIA study, including the population and environmentally sensitive areas protected, environmentally friendly designs recommended, key environmental problems avoided, compensation areas included and the environmental benefits of environmental protection measures recommended.

3.6.7.2 The potential net environmental benefits, in particular from air emission point of view, due to the replacement of the existing crematorium by the new crematorium shall be stated.

3.6.8 Environmental Monitoring and Audit (EM&A) Requirements

3.6.8.1 The Applicant shall present in the EIA study a detailed environmental monitoring program including the frequency of measurements of dioxins and other pollutants for air emissions and ashes. In addition, the Applicant shall also identify in the EIA study whether there is any need for other EM&A requirements during the construction and operation phases of the proposed developments. The scope of the the environmental monitoring program and, if identified, other EM&A requirements for the Project shall be clearly defined in the EIA study.

3.6.8.2 The Applicant shall comply with the requirements as stipulated in Annex 21 of the TM.

3.6.8.3 The Applicant shall prepare a project implementation schedule (in the form of a checklist as shown in Appendix C to this EIA study brief) containing all the EIA study recommendations and mitigation measures with reference to the implementation programme.

4. DURATION OF VALIDITY

This EIA study brief is valid for 36 months from the date of issue. If the EIA study does not commence within this period, the Applicant shall apply to the Director for another EIA study brief afresh before commencement of the EIA study.

5. REPORT REQUIREMENTS

5.1 In preparing the EIA report, the Applicant shall refer to Annex 11 of the TM for the contents of an EIA report. The Applicant shall also refer to Annex 20 of the TM which stipulates the guidelines for the review of an EIA report.

5.2 The Applicant shall supply the Director with the following number of copies of the EIA report and the Executive Summary :

(i) 50 copies of the EIA report in English and 80 copies of the executive summary (each bilingual in both English and Chinese) as required under section 6(2) of the EIAO to be supplied at the time of application for approval of the EIA report.

(ii) when necessary, addendum to the EIA report and the executive summary submitted in 5.2 (i) above as required under section 7(1) of the EIAO, to be supplied upon advice by the Director for public inspection.

(iii) 20 copies of the EIA report in English and 50 copies of the executive summary (each bilingual in both English and Chinese) with or without Addendum as required under section 7(5) of the EIAO, to be supplied upon advice by the Director for consultation with the Advisory Council on the Environment.

5.3 The Applicant shall, upon request, make additional copies of the above documents available to the public, subject to payment by the interested parties of full costs of printing.

5.4 In addition, to facilitate the public inspection of the EIA Report via the EIAO Internet Website, the applicant shall provide electronic copies of both the EIA Report and the Executive Summary Report prepared in HyperText Markup Language (HTML) (version 4.0 or later) and in Portable Document Format (PDF version 4.0 or later), unless otherwise agreed by the Director. For the HTML version, a content page capable of providing hyperlink to each section and sub-section of the EIA Report and the Executive Summary Report shall be included in the beginning of the document. Hyperlinks to all figures, drawings and tables in the EIA Report and Executive Summary shall be provided in the main text from where the respective references are made. All graphics in the report shall be in interlaced GIF format unless otherwise agreed by the Director.

5.5 The electronic copies of the EIA report and the Executive Summary shall be submitted to the Director at the time of application for approval of the EIA Report.

5.6 When the EIA Report and the Executive Summary are made available for public inspection under section 7(1) of the EIA Ordinance, the content of the electronic copies of the EIA Report and the Executive Summary must be the same as the hard copies and the Director shall be provided with the most updated electronic copies.

5.7 To promote environmentally friendly and efficient dissemination of information, both hardcopies and electronic copies of future EM&A reports recommended by the EIA study shall be required and their format shall be agreed by the Director.

6. OTHER PROCEDURAL REQUIREMENTS

6.1 During the course of the EIA study, if there is any change in the name of Applicant for this EIA study brief, the Applicant in this study brief must notify the Director immediately.

6.2 If there is any key change in the scope of the Project mentioned in Section 1.2 of this EIA study brief and in Project Profile (No. PP-166/2002), the Applicant must seek confirmation from the Director in writing on whether or not the scope of issues covered by this EIA study brief can still cover the key changes, and the additional issues, if any, that the EIA study must also address. If the changes to the Project fundamentally alter the key scope of the EIA study brief, the Applicant shall apply to the Director for a fresh EIA study brief.

--- END OF EIA STUDY BRIEF ---

May 2002

Environmental Assessment and Noise Division

Environmental Protection Department

APPENDIX B-1

Guidelines on Choice of Models and Model Parameters

1. Introduction

1.1 To expedite the review process by the Authority and to assist project proponents or environmental consultants with the conduct of air quality modelling exercises which are frequently called for as part of environmental impact assessment studies, this paper describes the usage and requirements of a few commonly used air quality models.

2. Choice of models

2.1 The models which have been most commonly used in air quality impact assessments, due partly to their ease of use and partly to the quick turn-around time for results, are of Gaussian type and designed for use in simple terrain under uniform wind flow. There are circumstances when these models are not suitable for ambient concentration estimates and other types of models such as physical, numerical or mesoscale models will have to be used. In situations where topographic, terrain or obstruction effects are minimal between source and receptor, the following Gaussian models can be used to estimate the near-field impacts of a number of source types including dust, traffic and industrial emissions.

Model	Applications
FDM	for evaluating fugitive and open dust source impacts (point, line and area sources)
CALINE4	for evaluating mobile traffic emission impacts (line sources)
ISCST3	for evaluating industrial chimney releases as well as area and volumetric sources (point, area and volume sources); line sources can be approximated by a number of volume sources.

These frequently used models are also referred to as Schedule 1 models (see attached list).

2.2 Note that both FDM and CALINE4 have a height limit on elevated sources (20 m and 10m, respectively). Source of elevation above these limits will have to be modelled using the ISCST3 model or suitable alternative models. In using the latter, reference should be made to the 'Guidelines on the Use of Alternative Computer Models in Air Quality Assessment'.

2.3 The models can be used to estimate both short-term (hourly and daily average) and long-term (annual average) ambient concentrations of air pollutants. The model results, obtained using appropriate model parameters (refer to Section 3) and assumptions, allow direct comparison with the relevant air quality standards such as the Air Quality Objectives (AQOs) for the relevant pollutant and time averaging period.

3. Model input requirements

3.1 Meteorological Data

3.1.1 At least 1 year of recent meteorological data (including wind speed, wind direction, stability class, ambient temperature and mixing height) from a weather station either closest to or having similar characteristics as the study site should be used to determine the highest short-term (hourly, daily) and long-term (annual) impacts at identified air sensitive receivers in that period. The amount of valid data for the period should be no less than 90 percent.

3.1.2 Alternatively, the meteorological conditions as listed below can be used to examine the worst case short-term impacts:

Day time:
stability class D; wind speed 1 m/s (at 10m height); worst-case wind angle; mixing height 500 m

Night time:
stability class F; wind speed 1 m/s (at 10m height); worst case wind angle; mixing height 500 m

This is a common practice with using the CALINE4 model due to its inability to handle lengthy data set.

3.1.3 For situations where, for example, (i) the model (such as CALINE4) does not allow easy handling of one full year of meteorological data; or (ii) model run time is a concern, the followings can be adopted in order to determine the daily and annual average impacts:

(i)    perform a frequency occurrence analysis of one year of meteorological data to determine the actual wind speed (to the nearest unit of m/s), wind direction (to the nearest 10^o) and stability (classes A to F) combinations and their frequency of occurrence;
(ii)    determine the short term hourly impact under all of the identified wind speed, wind direction and stability combinations; and
(iii)    apply the frequency data with the short term results to determine the long term (daily / annual) impacts.

Apart from the above, any alternative approach that will capture the worst possible impact values (both short term and long term) may also be considered.

3.1.4 Note that the anemometer height (relative to a datum same for the sources and receptors) at which wind speed measurements were taken at a selected station should be correctly entered in the model. These measuring positions can vary greatly from station to station and the vertical wind profile employed in the model can be grossly distorted from the real case if incorrect anemometer height is used. This will lead to unreliable concentration estimates.

3.1.5 An additional parameter, namely, the standard deviation of wind direction, σ_Θ, needs to be provided as input to the CALINE4 model. Typical values ofσ_Θrange from 12^o for rural areas to 24^o for highly urbanised areas under 'D' class stability. For semi-rural such as new development areas, 18^o is more appropriate under the same stability condition. The following reference can be consulted for typical ranges of standard deviation of wind direction under different stability categories and surface roughness conditions.

Ref.(1): Guideline On Air Quality Models (Revised), EPA-450/2-78-027R, United States Environmental Protection Agency, July 1986.

3.2 Emission Sources

All the identified sources relevant to a process plant or a study site should be entered in the model and the emission estimated based on emission factors compiled in the AP-42 (Ref. 2) or other suitable references. The relevant sections of AP-42 and any parameters or assumptions used in deriving the emission rates (in units g/s, g/s/m or g/s/m²) as required by the model should be clearly stated for verification. The physical dimensions, location, release height and any other emission characteristics such as efflux conditions and emission pattern of the sources input to the model should also correspond to site data.

If the emission of a source varies with wind speed, the wind speed-dependent factor should be entered.

Ref.(2): Compilation of Air Pollutant Emission Factors, AP-42, 5^thEdition, United States Environmental Protection Agency, January 1995.

3.3 Urban/Rural Classification

Emission sources may be located in a variety of settings. For modelling purposes these are classed as either rural or urban so as to reflect the enhanced mixing that occurs over urban areas due to the presence of buildings and urban heat effects. The selection of either rural or urban dispersion coefficients in a specific application should follow a land use classification procedure. If the land use types including industrial, commercial and residential uses account for 50% or more of an area within 3 km radius from the source, the site is classified as urban; otherwise, it is classed as rural.

3.4 Surface Roughness Height

This parameter is closely related to the land use characteristics of a study area and associated with the roughness element height. As a first approximation, the surface roughness can be estimated as 3 to 10 percent of the average height of physical structures. Typical values used for urban and new development areas are 370 cm and 100 cm, respectively.

3.5 Receptors

These include discrete receptors representing all the identified air sensitive receivers at their appropriate locations and elevations and any other discrete or grid receptors for supplementary information. A receptor grid, whether Cartesian or Polar, may be used to generate results for contour outputs.

3.6 Particle Size Classes

In evaluating the impacts of dust-emitting activities, suitable dust size categories relevant to the dust sources concerned with reasonable breakdown in TSP (< 30 μm) and RSP (< 10 μm) compositions should be used.

3.7 NO₂ to NO_x Ratio

The conversion of NO_x to NO₂ is a result of a series of complex photochemical reactions and has implications on the prediction of near field impacts of traffic emissions. Until further data are available, three approaches are currently acceptable in the determination of NO₂:

(a)    Ambient Ratio Method (ARM) - assuming 20% of NO_x to be NO₂; or
(b)    Discrete Parcel Method (DPM, available in the CALINE4 model); or
(c)     Ozone Limiting Method (OLM) - assuming the tailpipe NO₂ emission to be 7.5% of NO_x and the background ozone concentration to be in the range of 57 to 68 μg/m³ depending on the land use type (see also EPD reference paper 'Guidelines on Assessing the 'TOTAL' Air Quality Impacts').

3.8 Odour Impact

In assessing odour impacts, a much shorter time-averaging period of 5 seconds is required due to the shorter exposure period tolerable by human receptors. Conversion of model computed hourly average results to 5-second values is therefore necessary to enable comparison against recommended standard. The hourly concentration is first converted to 3-minute average value according to a power law relationship which is stability dependent (Ref. 3) and a result of the statistical nature of atmospheric turbulence. Another conversion factor (10 for unstable conditions and 5 for neutral to stable conditions) is then applied to convert the 3-minute average to 5-second average (Ref. 4). In summary, to convert the hourly results to 5-second averages, the following factors can be applied:

	Stability Category	1-hour to 5-sec Conversion Factor
	A & B	45
	C	27
	D	9

Under 'D' class stability, the 5-second concentration is approximately 10 times the hourly average result. Note, however, that the combined use of such conversion factors together with the ISCST results may not be suitable for assessing the extreme close-up impacts of odour sources.

Ref.(3): Richard A. Duffee, Martha A. O' Brien and Ned Ostojic, 'Odor Modeling - Why and How', Recent Developments and Current Practices in Odor Regulations, Controls and Technology, Air & Waste Management Association, 1991.

Ref.(4): A.W.C. Keddie, 'Dispersion of Odours', Odour Control - A Concise Guide, Warren Spring Laboratory, 1980.

3.9 Plume Rise Options

The ISCST3 model provides by default a list of the U.S. regulatory options for concentration calculations. These are all applicable to the Hong Kong situations except for the 'Final Plume Rise' option. As the distance between sources and receptors are generally fairly close, the non-regulatory option of 'Gradual Plume Rise' should be used instead to give more accurate estimate of near-field impacts due to plume emission. However, the 'Final Plume Rise' option may still be used for assessing the impacts of distant sources.

3.10 Portal Emissions

These include traffic emissions from tunnel portals and any other similar openings and are generally modelled as volume sources according to the PIARC 91 (or more up-to-date version) recommendations (Ref. 5, section III.2). For emissions arising from underpasses or any horizontal openings of the like, these are treated as area or point sources depending on the source physical dimensions. In all these situations, the ISCST3 model or more sophisticated models will have to be used instead of the CALINE4 model. In the case of portal emissions with significant horizontal exit velocity which cannot be handled by the ISCST3 model, the impacts may be estimated by the TOP model (Ref. 6) or any other suitable models subject to prior agreement with EPD. The EPD's 'Guidelines on the Use of Alternative Computer Models in Air Quality Assessment' should also be referred to.

Ref.(5): XIXth World Road Congress Report, Permanent International Association of Road Congresses (PIARC), 1991.

Ref.(6): N. Ukegunchi, H. Okamoto and Y. Ide "Prediction of vehicular emission pollution around a tunnel mouth", Proceedings 4th International Clean Air Congress, pp. 205-207, Tokyo, 1977.

3.11 Background Concentrations

Background concentrations are required to account for far-field sources which cannot be estimated by the model. These values, to be used in conjunction with model results for assessing the total impacts, should be based on long term average of monitoring data at location representative of the study site. Refer to EPD reference paper 'Guidelines on Assessing the 'TOTAL' Air Quality Impacts' for further information.

3.12 Output

The highest short-term and long-term averages of pollutant concentrations at prescribed receptor locations are output by the model and to be compared against the relevant air quality standards specified for the relevant pollutant. Contours of pollutant concentration are also required for indicating the general impacts of emissions over a study area.

Copies of model files in electronic format should also be provided for EPD's reference.

The information contained in this Appendix is only meant to assist the Applicant in performing the air quality assessment. The Applicant must exercise professional judgement in applying this general information for the Project.

Schedule 1

Air Quality Models Generally Accepted by

Hong Kong Environmental Protection Department for

Regulatory Applications as at 1 July 1998*

Industrial Source Complex Dispersion Model - Short Term Version 3 (ISCST3) or the latest version developed by U.S. Environmental Protection Agency

California Line Source Dispersion Model Version 4 (CALINE4) or the latest version developed by Department of Transportation, State of California, U.S.A.

Fugitive Dust Model (FDM) or the latest version developed by U.S. Environmental Protection Agency

* EPD is continually reviewing the latest development in air quality models and will update this Schedule accordingly.

APPENDIX B-2

Guidelines on Assessing the 'TOTAL' Air Quality Impacts

1. Total Impacts - 3 Major Contributions

1.1 In evaluating the air quality impacts of a proposed project upon air sensitive receivers, contributions from three classes of emission sources depending on their distance from the site should be considered. These are:

	Primary contributions:	project induced
	Secondary contributions:	pollutant-emitting activities in the immediate neighbourhood
	Other contributions:	pollution not accounted for by the previous two (Background contributions)

2. Nature of Emissions

2.1 Primary contributions

In most cases, the project-induced emissions are fairly well defined and quite often (but not necessarily) the major contributor to local air quality impacts. Examples include those due to traffic network, building or road construction projects.

2.2 Secondary contributions

Within the immediate neighbourhood of the project site, there are usually pollutant emitting activities contributing further to local air quality impacts. For most local scale projects, any emission sources in an area within 500m radius of the project site with notable impacts should be identified and included in an air quality assessment to cover the short-range contributions. In the exceptional cases where there is one or more significant sources nearby, the study area may have to be extended or alternative estimation approach employed to ensure these impacts are reasonably accounted for.

2.3 Background contributions

The above two types of emission contributions should account for, to a great extent, the air quality impacts upon local air sensitive receivers, which are often amenable to estimation by the 'Gaussian Dispersion' type of models. However, a background air quality level should be prescribed to indicate the baseline air quality in the region of the project site, which would account for any pollution not covered by the two preceding contributions. The emission sources contributing to the background air quality would be located further afield and not easy to identify. In addition, the transport mechanism by which pollutants are carried over long distances (ranging from 1km up to tens or hundreds of kms) is rather complex and cannot be adequately estimated by the 'Gaussian' type of models.

3. Background Air Quality - Estimation Approach

3.1 The approach

In view of the difficulties in estimating background air quality using the air quality models currently available, an alternative approach based on monitored data is suggested. The essence of this approach is to adopt the long-term (5-year) averages of the most recent monitored air quality data obtained by EPD. These background data would be reviewed yearly or biennially depending on the availability of the monitored data. The approach is a first attempt to provide a reasonable estimate of the background air quality level for use in conjunction with EIA air quality assessment to address the cumulative impacts upon a locality. This approach may be replaced or supplemented by superior modelling efforts such as that entailed in PATH (Pollutants in the Atmosphere and their Transport over Hong Kong), a comprehensive territory-wide air quality modelling system currently being developed for Hong Kong. Notwithstanding this, the present approach is based on measured data and their long term regional averages; the background values so derived should therefore be indicative of the present background air quality. In the absence of any other meaningful way to estimate a background air quality for the future, this present background estimate should also be applied to future projects as a first attempt at a comprehensive estimate until a better approach is formulated.

3.2 Categorisation

The monitored air quality data, by 'district-averaging' are further divided into three categories, viz, Urban, Industrial and Rural/New Development. The background pollutant concentrations to be adopted for a project site would depend on the geographical constituency to which the site belongs. The categorisation of these constituencies is given in Section 3.4. The monitoring stations suggested for the 'district-averaging'(arithmetic means) to derive averages for the three background air quality categories are listed as follows:

Urban: Kwun Tong, Sham Shui Po, Tsim Sha Tsui and Central/Western
Industrial: Kwun Tong, Tsuen Wan and Kwai Chung
Rural/New Development: Sha Tin, Tai Po, Junk Bay, Hong Kong South and Yuen Long

The averaging would make use of data from the above stations wherever available. The majority of the monitoring stations are located some 20m above ground.

3.3 Background pollutant values

Based on the above approach, background values for the 3 categories have been obtained for a few major air pollutants as follows:

POLLUTANT	URBAN	INDUSTRIAL	RURAL/NEW DEVELOPMENT
NO₂	59	57	39
SO₂	21	26	13
O₃	62	68	57
TSP	98	96	87
RSP	60	58	51

All units are in micrograms per cubic metre. The above values are derived from 1992 to 1996 annual averages with the exception of ozone which represent annual average of daily hourly maximum values for year 1996.

In cases where suitable air quality monitoring data representative of the study site such as those obtained from a nearby monitoring station or on-site sampling are not available for the prescription of background air pollution levels, the above tabulated values can be adopted instead. Strictly speaking, the suggested values are only appropriate for long term assessment. However, as an interim measure and until a better approach is formulated, the same values can also be used for short term assessment. This implies that the short term background values will be somewhat under-estimated, which compensates for the fact that some of the monitoring data are inherently influenced by secondary sources because of the monitoring station location.

Indeed, if good quality on-site sampling data which cover at least one year period are available, these can be used to derive both the long term (annual) and short term (daily / hourly) background values, the latter are usually applied on an hour to hour, day to day basis.

3.4 Site categories

The categories to which the 19 geographical constituencies belong are listed as follows:

DISTRICT	AIR QUALITY CATEGORY
Islands	Rural/New Development
Southern	Rural/New Development
Eastern	Urban
Wan Chai	Urban
Central & Western	Urban
Sai Kung	Rural/New Development
Kwun Tong	Industrial
Wong Tai Sin	Urban
Kowloon City	Urban
Yau Tsim	Urban
Mong Kok	Urban
Sham Shui Po	Urban
Kwai Tsing	Industrial
Sha Tin	Rural/New Development
Tsuen Wan	Industrial
Tuen Mun	Rural/New Development
Tai Po	Rural/New Development
Yuen Long	Rural/New Development
Northern	Rural/New Development

3.5 Provisions for ‘double-counting’

The current approach is, by no means, a rigorous treatment of background air quality but aims to provide an as-realistic-as-possible approximation based on limited field data. 'Double-counting' of 'secondary contributions' may be apparent through the use of such 'monitoring-based' background data as some of the monitoring stations are of close proximity to existing emission sources. 'Primary contributions' due to a proposed project (which is yet to be realised) will not be double-counted by such an approach. In order to avoid over-estimation of background pollutant concentrations, an adjustment to the values given in section 3.3 is possible and optional by multiplying the following factor:

(1.0 - ESecondary contributions/ETerritory)

where E stands for emission.

The significance of this factor is to eliminate the fractional contribution to background pollutant level of emissions due to 'secondary contributions' out of those from the entire territory. In most cases, this fractional contribution to background pollutant levels by the secondary contributions is minimal.

4. Conclusions

4.1 The above described approach to estimating the total air quality impacts of a proposed project, in particular the background pollutant concentrations for air quality assessment, should be adopted with immediate effect. Use of short term monitoring data to prescribe the background concentrations is no longer acceptable.

APPENDIX B-3

Guidelines on the Use of Alternative Computer Models
in Air Quality Assessment

1. Background

1.1 In Hong Kong, a number of Gaussian plume models are commonly employed in regulatory applications such as application for specified process licences and environmental impact assessments (EIAs). These frequently used models (as listed in Schedule 1 attached; hereafter referred to as Schedule 1 models) have no regulatory status but form the basic set of tools for local-scale air quality assessment in Hong Kong.

1.2 However, no single model is sufficient to cover all situations encountered in regulatory applications. In order to ensure that the best model available is used for each regulatory application and that a model is not arbitrarily applied, the project proponent (and/or its environmental consultants) should assess the capabilities of various models available and adopt one that is most suitable for the project concerned.

1.3 Examples of situations where the use of an alternative model is warranted include:

(i) the complexity of the situation to be modelled far exceeds the capability of the Schedule 1 models; and
(ii) the performance of an alternative model is comparable or better than the Schedule 1 models.

1.4 This paper outlines the demonstration / submission required in order to support the use of an alternative air quality model for regulatory applications for Hong Kong.

2. Required Demonstration / Submission

2.1 Any model that is proposed for air quality applications and not listed amongst the Schedule 1 models will be considered by EPD on a case-by-case basis. In such cases, the proponent will have to provide the followings for EPD's review:

(i) Technical details of the proposed model; and
(ii) Performance evaluation of the proposed model

Based on the above information, EPD will determine the acceptability of the proposed model for a specific or general applications. The onus of providing adequate supporting materials rests entirely with the proponent.

2.2 To provide technical details of the proposed model, the proponent should submit documents containing at least the following information:

(i) mathematical formulation and data requirements of the model;
(ii) any previous performance evaluation of the model; and
(iii) a complete set of model input and output file(s) in commonly used electronic format.

2.3 On performance evaluation, the required approach and extent of demonstration varies depending on whether a Schedule 1 model is already available and suitable in simulating the situation under consideration. In cases where no Schedule 1 model is found applicable, the proponent must demonstrate that the proposed model passes the screening test as set out in USEPA Document "Protocol for Determining the Best Performing Model" (Ref. 1).

2.4 For cases where a Schedule 1 model is applicable to the project under consideration but an alternative model is proposed for use instead, the proponent must demonstrate either that

(i) the highest and second highest concentrations predicted by the proposed model are within 2 percent of the estimates obtained from an applicable Schedule 1 model (with appropriate options chosen) for all receptors for the project under consideration; or

(ii) the proposed model has superior performance against an applicable Schedule 1 model based on the evaluation procedure set out in USEPA Document "Protocol for Determining the Best Performing Model" (Ref. 1).

2.5 Should EPD find the information on technical details alone sufficient to indicate the acceptability of the proposed model, information on further performance evaluation as specified in Sections 2.3 and 2.4 above would not be necessary.

2.6 If the proposed model is an older version of one of the Schedule 1 models or was previously included in Schedule 1, the technical documents mentioned in Section 2.2 are normally not required. However, a performance demonstration of equivalence as stated in Section 2.4 (i) would become necessary.

2.7 If EPD is already in possession of some of the documents that describe the technical details of the proposed model, submission of the same by the proponent is not necessary. The proponent may check with EPD to avoid sending in duplicate information.

Schedule 1
Air Quality Models Generally Accepted by
Hong Kong Environmental Protection Department for
Regulatory Applications as at 1 July 1998*

Industrial Source Complex Dispersion Model - Short Term Version 3 (ISCST3) or the latest version developed by U.S. Environmental Protection Agency

California Line Source Dispersion Model Version 4 (CALINE4) or the latest version developed by Department of Transportation, State of California, U.S.A.

Fugitive Dust Model (FDM) or the latest version developed by U.S. Environmental Protection Agency

Ref. (1): William M. Cox, "Protocol for Determining the Best Performing Model" Publication No. EPA-454/R-92-025; U.S. Environmental Protection Agency, Research Triangle Park, NC.

* EPD is continually reviewing the latest development in air quality models and will update this Schedule accordingly.

APPENDIX B-4

Guidelines on Estimating Height Restriction and
Position of Fresh Air Intake Using Gaussian Plume Models

1. Introduction

1.1 Two situations in Hong Kong call for an assessment of ambient pollution concentration as a function of height, namely, the determination of

(i) height restriction for new buildings in areas subject to poor air quality aloft as a result of elevated emission sources nearby; and

(ii) optimum / acceptable location of fresh-air intakes for centrally air-conditioned buildings.

1.2 Simple Gaussian plume models like the Industrial Source Complex Dispersion Model - Short Term Version 3 (ISCST3) have been commonly used in Hong Kong for predicting air quality with a view to addressing the two situations above. This guideline provides a practical approach to applying the ISCST3 model to these two situations in order to safeguard air quality. The application limits of the ISCST3 model must, however, be observed (refer to its User's Guide). Suitable alternatives such as wind tunnel modelling or more sophisticated numerical modelling may have to be used instead if the situation warrants.

2. Approach

2.1 The concentration pattern at sensitive receivers produced by emissions from a single stack is different from that produced by multiple stacks. However, in most cases, the emission characteristics of one particular stack can be used to approximate the concentration pattern at sensitive receivers due to its dominance. An exception to this generalisation occurs when there exist a number of stacks concentrating in a small area but having large differences in emission characteristics such as emission height, stack dimensions, efflux velocity and temperature.

General Situation

2.2 A case can be considered general if it belongs to one of the following categories:

(i) Vertical concentration profile at receptors is contributed solely by emissions from one stack with diameter less than or equal to 1m;

(ii) Vertical concentration profile at receptors is dominated by emissions from one stack with none of the contributing stacks having tip diameter larger than 1m and the stacks are not clustered in space (i.e. not of similar distance nor in the same direction from the receptor);

(iii) Vertical concentration profile at receptors is dominated by emissions from more than one stack with no contributing stack(s) having tip diameter larger than 1m and the stacks are not clustered horizontally; and

(iv) Vertical concentration profile at receptors is dominated by emissions from more than one stack with no contributing stack(s) having tip diameter larger than 1m and the dominant stacks clustered horizontally, but the stack gas characteristics and emission heights of these dominant stacks are not significantly different.

2.3 Since only fewer than 3% of stacks registered in Hong Kong have tip diameter larger than 1m, these "large" stacks are treated individually as suggested in section 2.5.

2.4 For the general case, we have performed a sensitivity study (Annex I) based on a single stack to determine the uncertainty associated with plume heights arising from input data of limited accuracy. On the basis of these findings, we recommend the followings:

(i) Conduct an air quality modelling exercise using the stack emission characteristics dictated by the situation.

(ii) The restricted height range will be the region of unacceptable air quality with a 10m safety margin added to both ends. The modelling exercise should therefore address the full receptor height range and 10m beyond.

Special Situation

2.5 For all other situations not covered by those in Section 2.2 above, the following procedures are recommended:

(i) Conduct an air quality modelling exercise using the minimum values of stack gas exit velocity and stack gas temperature (i.e. 6ms^-1 and 373K, respectively).

(ii) Conduct a second modelling exercise based on the maximum (or calculated, whichever is higher) values of stack gas exit velocity and stack gas temperature of the respective ranges (Table 1).

(iii) The results from the first and second runs above are then used to delimit the upper and lower end of the range of unacceptable air quality, respectively.

2.6 In conducting the air quality modelling exercise, background pollutant concentrations should also be allowed for. The "Guidelines on Assessing the 'TOTAL' Air Quality Impacts" can be referred to.

Annex I

Sensitivity Study on the Height of Maximum Impact at a Receptor

A. Approach

A.1 In assessing the impact of emission from a point source using ISCST3, the following parameters would affect the plume rise:

a. stack height;
b. stack diameter;
c. stack gas temperature;
d. stack gas exit velocity;
e. ambient temperature; and
f. stack tip wind velocity.

A.2 The first two parameters above are clearly specified and not subject to change. The last two parameters are part of the meteorological input independent of plume characteristics. Uncertainty in the plume rise calculation is introduced through:

a. the limited ability of the plume rise algorithm to replicate nature; and

b. the uncertainty in the effluent's characteristics as represented by the stack gas temperature and stack gas exit velocity.

A.3 The first type of uncertainty attends all mathematical representation of complex reality. Users of model results will have to come to terms with this limitation. However, in modelling air quality for general environmental assessment (e.g. ground level concentration, safe set-back distance, ..., etc.), attempts are usually made to produce a 'conservative' estimate. Though this conservative estimate does not address the accuracy of the algorithm, which varies from case to case and cannot be determined without an unrealistic amount of monitoring in most cases, it is generally practiced and accepted as sufficient to safeguard the air quality at sensitive receivers.

A.4 In the same vein, we are attempting to specify procedures that would produce 'conservative' results to safeguard air quality at air sensitive receptors that are dependent on the vertical position of the plume. The complication in this attempt is the definition of 'conservative' results. For the case of height restriction, estimation based on a lower plume rise would be conservative. For determining the optimum locations of fresh-air intakes, enough margin would have to be allowed for at both the upper and lower ends of the acceptable locations.

A.5 Since the values of the stack gas temperature and stack gas exit velocity affect the plume rise, a sensitivity test was conducted to delimit the uncertainty in plume rise due to these two parameters.

B. Sensitivity Study

B.1 The base case of the sensitivity test is selected such that the plume rise due to buoyancy (represented by the stack gas temperature) and momentum (represented by the stack gas exit velocity) is at a minimum. This corresponds to choosing the minimum values of the stack gas exit velocity and temperature in the respective ranges. Performing sensitivity tests on this base case would amplify the resulting deviation, thus producing conservative results.

B.2 By studying the emission characteristics of the industrial stacks in Hong Kong, it is found that exit velocities and stack gas temperatures for most industrial stacks vary between 6 - 10 ms^-1 and 373 - 573K. For the sensitivity tests, the values of the exit gas velocity and exit gas temperature are varied within these ranges to determine the maximum uncertainty in plume rise. The details of the parameters used in the base case are given in Table 1.

B.3 The same procedure was repeated for different values of the stack tip diameter (between 0.1 and 1m) and for different ambient temperatures (between 0 and 40^oC).

C. Results

C.1 Within a horizontal distance of 20 to 1,000m from the stack, the sensitivity tests’ results show that the plume centre line height will not differ by more than 10m from that of the base case for the specified ranges of parameter values. Also, within the ranges tested, this plume centre line height is not significantly affected by the ambient temperature and stack tip diameter. Furthermore, the maximum concentration at a certain distance from the stack is not sensitive to the changes in the stack gas exit velocity and stack gas temperature.

C.2 Further tests show that some plume rise values resulting from the specified ranges of parameters may deviate from the base case plume rise by more than 10m if the stack tip diameter is larger than 1m.

Table 1

Input Parameters in the Base Case

Chimney Characteristics	Rationale
height of emission - 100m	the height was chosen to represent the typical height of emission for chimneys in industrial areas
stack tip diameter - 1m	approximate 97% of the stacks have diameters less than 1m according to EPD's Enforcement Management System (EMS)
exit velocity - 6 ms^-1	the minimum exit velocity required by the licence
exit gas temperature - 373K	the minimum of the range typical of those stacks servicing industrial boilers
emission strength - 1gs^-1	a reference emission strength

Meteorological Conditions	Rationale
(included in a meteorological file) wind speed & stability class	follows the USEPA's meteorological conditions for screening procedure, i.e. A: 1, 2, 3 ms^-1 B: 1, 2, 3, 4, 5 ms^-1 C: 1, 2, 3, 4, 5, 8, 10 ms^-1 D: 1, 2, 3, 4, 5, 8, 10, 15, 20 ms^-1 E: 1, 2, 3, 4, 5 ms^-1 F: 1, 2, 3, 4 ms^-1
mixing height - 500m	as the emission height of the source is at 100m, the predicted concentration and the height of maximum impact are insensitive to this value
ambient temperature - 298K	a typical ambient temperature used in Hong Kong

Receptor
receptor distance
- 20, 40, 60, 80, 100, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000m downwind from the source
receptor height
- 80 - 200m of 10m intervals

Other Options
(following typical choices in modelling exercises)
dispersion coefficient - urban
wind profile exponents - default
vertical temperature gradient - default
gradual plume rise option
stack tip downwash option
no building downwash option

The information contained in this Appendix is only meant to assist the Applicant in performing the air quality assessment. The Applicant must exercise professional judgement in applying this general information for the Project.

EIA Ref.	EM&A Ref.	Recommended Mitigation Measures	Objectives of the Recommended Measure & Main Concerns to address	Who to implement the measure ?	Location of the measure	When to implement the measure ?	What requirements or standards for the measure to achieve ?