HKIQEP Study Guide v.2024.0510 for Lau Chin Tung PDF
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This document is a study guide for Professional Assessment (Part 1) of the Hong Kong Institute of Qualified Environmental Professionals Limited (HKIQEP). It details the content of the guide, including its table of contents, which covers topics in environmental science, management and policy.
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This copy is issued to Lau Chin Tung Professional Assessment (Part I) Study Guide...
This copy is issued to Lau Chin Tung Professional Assessment (Part I) Study Guide Version 2024.05.10 Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. This copy is issued to Lau Chin Tung For inquiries: Address: GPO Box 12309, Central, Hong Kong Email: [email protected] Website: www.hkiqep.org/ Warning: No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording or any information storage and retrieval system without the express written permission of the copyright owner. All requests for permission to reproduce the materials from this study guide and purchase copies should be directed to Hong Kong Institute of Qualified Environmental Professionals Limited. V.2024.05.10 Page i Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. Disclaimer This Study Guide serves as a GUIDELINE DOCUMENT in preparation for HKIQEP Professional Assessment (Part I) and other educational purposes. It is not intended to be a complete representation of the syllabus for HKIQEP Professional Assessment (Part I). There may be questions in the Assessment not addressed in this Study Guide and conversely, not everything in this Study Guide will appear in the Assessment. We have taken great efforts to ensure the accuracy of the information contained in this guide. However, the content and interpretation of some environmental topics are subject to change. We assume no responsibilities for any actions as a result of the use or reliance on this Study Guide. We would be grateful if there are any suggestions from readers that would be helpful to us in improving this Study Guide. This copy is issued to Lau Chin Tung V.2024.05.10 Page ii Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. Table of Contents I. Air............................................................................................................ 1 1 Nature of Atmospheric Pollution................................................................................................ 2 1.1 Physical structure and composition of the troposphere and stratosphere....................... 2 1.2 Natural composition of the atmosphere............................................................................ 2 1.3 Air pollutants...................................................................................................................... 3 1.4 Physical and chemical pollutant processes........................................................................ 5 1.5 Local, regional and global air pollution.............................................................................. 9 1.6 Indoor air pollution........................................................................................................... 12 2 Air Pollution Sources and Impacts............................................................................................ 15 2.1 Anthropogenic sources of air pollution............................................................................ 15 This copy is issued to Lau Chin Tung 2.2 Natural sources of air pollution........................................................................................ 16 2.3 Receptors (human, animal, plant, materials, atmospheric processes)............................ 16 2.4 Source / receptor relationships (spatial & temporal)...................................................... 16 2.5 Adverse effects................................................................................................................. 17 2.6 Health impact assessments, economic impact assessments, air toxics and risk assessments...................................................................................................................... 20 3 Air Pollution Modelling............................................................................................................. 22 3.1 Purposes of air quality modelling..................................................................................... 22 3.2 Levels of modelling effort................................................................................................. 22 3.3 Types of air pollution models........................................................................................... 22 3.4 Emission inventory and emission modelling.................................................................... 25 3.5 Model limitations, assumptions, accuracy....................................................................... 26 3.6 Source / receptor relationships........................................................................................ 27 3.7 Air quality forecasting...................................................................................................... 29 4 Air Quality Management Strategies.......................................................................................... 30 4.1 Air pollution prevention versus control........................................................................... 30 4.2 Best practicable means and technology forcing approach.............................................. 30 4.3 Air quality standards approach and criteria pollutants.................................................... 31 4.4 Market-based mechanism, emission trading, emission offsetting.................................. 31 4.5 Cost-benefit approach...................................................................................................... 32 4.6 Socio-economic and political issues, polluter pays principle........................................... 32 4.7 Regulatory and non-regulatory approaches.................................................................... 33 4.8 Air quality and emission limits, air pollutant nuisance, prevention of significant deterioration.................................................................................................................... 35 4.9 Dissemination of air quality information and air quality index / air quality health index37 V.2024.05.10 Page iii Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. 4.10 Education and public awareness of air pollution............................................................. 38 4.11 Ordinances and subsidiary legislations on air quality management................................ 39 5 Air Pollution Control Technology.............................................................................................. 40 5.1 Control of emissions from stationary sources.................................................................. 40 5.2 Control of gaseous pollutants.......................................................................................... 40 5.3 Control of particulate pollutants...................................................................................... 42 5.4 Combustion control, fuel restriction and control, material restriction and control........ 43 5.5 Control of emissions from mobile sources, including vehicles, automotive, vessels, aircrafts............................................................................................................................. 45 5.6 Management and disposal of waste streams (multimedia)............................................. 48 5.7 Emission factors and estimates........................................................................................ 48 5.8 Compliance planning: limits, standards, technology, and documentation...................... 48 6 Ambient Air and Emission Sampling and Analysis.................................................................... 50 6.1 Ambient air quality monitoring........................................................................................ 50 This copy is issued to Lau Chin Tung 6.2 Meteorological monitoring.............................................................................................. 54 6.3 Emission sampling............................................................................................................ 54 6.4 Optical remote sensing..................................................................................................... 56 6.5 Instrumentation, data acquisition systems, data reporting............................................. 57 6.6 Quality control and assurance.......................................................................................... 57 6.7 Real-time monitoring versus intermittent discreet sampling / analysis.......................... 58 6.8 Health and safety precautions......................................................................................... 59 7 References................................................................................................................................ 60 II. Environmental Science, Management, and Policy (ESMP)...................... 61 8 Environmental Science Fundamentals...................................................................................... 62 8.1 An introduction to pollution............................................................................................. 65 8.2 Sources and types of environmental pollution................................................................ 68 8.3 Fate and transport of pollutants in the environment...................................................... 69 8.4 Ecology, health, and ecological effects of pollutants....................................................... 70 8.5 Data collection, analysis and modelling........................................................................... 71 8.6 Pollution control technologies......................................................................................... 74 8.7 Characterization of contaminated sites........................................................................... 76 8.8 Remediation and restoration technologies...................................................................... 76 9 Global and Multi-media Environmental Issues......................................................................... 77 9.1 Atmospheric ozone depletion.......................................................................................... 77 9.2 Global climate change...................................................................................................... 77 9.3 Greenhouse gas emissions inventory............................................................................... 79 9.4 Climate neutrality............................................................................................................. 79 V.2024.05.10 Page iv Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. 9.5 Ecological civilization........................................................................................................ 81 9.6 Indoor air quality.............................................................................................................. 82 9.7 Nutrient enrichment of waters........................................................................................ 82 9.8 Habitat degradation / destruction, biodiversity, endangered species............................. 83 9.9 Bioaccumulative substances............................................................................................ 83 9.10 Unconventional pollutants............................................................................................... 83 10 Environmental Impact, Site Assessment, and Risk Assessment Processes.............................. 84 10.1 Environmental impact assessment processes.................................................................. 84 10.2 Contaminated site assessment process........................................................................... 84 10.3 Risk assessment process................................................................................................... 85 11 Environmental Management Systems...................................................................................... 86 11.1 Organizational environmental policy............................................................................... 86 11.2 Identification of environmental aspects.......................................................................... 87 This copy is issued to Lau Chin Tung 11.3 Establishing goals and objectives..................................................................................... 87 11.4 Environmental performance indicators........................................................................... 88 11.5 Operational controls......................................................................................................... 89 11.6 Emergency response planning......................................................................................... 89 11.7 Incident investigation and corrective / preventive action............................................... 90 11.8 Environment and health................................................................................................... 90 11.9 Environmental auditing and corrective action................................................................. 90 11.10 Environmental due diligence related acquisitions and divestitures................................ 91 11.11 Total quality and environmental management (TQEM).................................................. 91 12 Pollution Prevention and Design for Environment................................................................... 94 12.1 Elements of pollution prevention..................................................................................... 94 12.2 Life-cycle assessment....................................................................................................... 95 12.3 Industrial ecology............................................................................................................. 95 12.4 Product and environmental stewardship......................................................................... 95 13 Sustainability............................................................................................................................. 97 13.1 Introduction and overview............................................................................................... 97 13.2 United Nations Sustainable Development Goals............................................................. 98 13.3 Sustainable business practices....................................................................................... 100 13.4 Energy resources and sustainability............................................................................... 100 13.5 Air quality and sustainability.......................................................................................... 101 13.6 Water resources and sustainability................................................................................ 101 13.7 Sustainable agriculture and food systems..................................................................... 102 13.8 Waste management and sustainability.......................................................................... 103 13.9 ESG and sustainability.................................................................................................... 103 13.10 Climate change and sustainability.................................................................................. 105 V.2024.05.10 Page v Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. 13.11 Environmental policy and governance........................................................................... 105 13.12 Summary and future directions...................................................................................... 105 14 Development and Implementation of Environmental Public Policy....................................... 106 14.1 Role of the public and other stakeholders in policy development................................ 106 14.2 Geopolitical considerations (local, regional, national, international)............................ 108 14.3 Role of science in public policy formulation................................................................... 108 14.4 Role of business to deliver............................................................................................. 109 14.5 Regulatory frameworks and mechanisms...................................................................... 109 15 International Environmental Conventions.............................................................................. 111 15.1 Conservation................................................................................................................... 111 15.2 Atmosphere.................................................................................................................... 115 15.3 Hazardous waste............................................................................................................ 116 15.4 Marine pollution............................................................................................................. 117 This copy is issued to Lau Chin Tung 15.5 Persistent Organic Pollutants (POPs)............................................................................. 123 15.6 Hazardous substances.................................................................................................... 123 16 References.............................................................................................................................. 125 III. Environmental Impact Assessment and Health Impact Assessment (EIA/HA).................................................................................................... 126 17 EIA Legal System..................................................................................................................... 127 17.1 Definition of designated project..................................................................................... 127 17.2 An overview of the statutory EIA process...................................................................... 127 17.3 EIAO statutory time limits.............................................................................................. 133 17.4 Function of the Environmental Study Management Group (ESMG).............................. 134 17.5 Definition of material change......................................................................................... 134 17.6 Vetting authorities.......................................................................................................... 134 17.7 Offences, penalties and appeals.................................................................................... 135 18 Consideration of Alternative & Mitigation Measures............................................................. 136 19 Evaluation of Impact............................................................................................................... 137 19.1 Air quality impact........................................................................................................... 137 19.2 Noise impact................................................................................................................... 141 19.3 Water quality impact...................................................................................................... 143 19.4 Sewerage/sewage impact.............................................................................................. 146 19.5 Waste management....................................................................................................... 147 19.6 Land contamination........................................................................................................ 149 19.7 Ecology........................................................................................................................... 150 19.8 Fisheries.......................................................................................................................... 154 19.9 Landscape and visual impact assessment (LVIA)............................................................ 156 V.2024.05.10 Page vi Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. 19.10 Cultural heritage............................................................................................................. 159 19.11 Hazard to life.................................................................................................................. 162 19.12 Health impact................................................................................................................. 163 20 Environmental Monitoring and Audit (EM&A)....................................................................... 164 20.1 Understanding of EP deliverables preparation.............................................................. 164 20.2 Key components of an EM&A programme.................................................................... 164 20.3 Qualified personnel – role of Independent Environmental Checker (IEC) / Environmental Team (ET)........................................................................................................................ 166 20.4 Understanding of implementation schedule and recommended mitigation measures 168 21 Stakeholders Engagement...................................................................................................... 169 21.1 Statutory control............................................................................................................ 169 21.2 Consultation technics..................................................................................................... 169 22 Strategic Environmental Assessment (SEA)............................................................................ 171 22.1 Statutory requirements.................................................................................................. 171 This copy is issued to Lau Chin Tung 22.2 Form and approach of SEA............................................................................................. 172 IV. Noise................................................................................................... 173 23 Fundamentals of Environmental Noise................................................................................... 174 23.1 Physics of sound............................................................................................................. 174 23.2 Psychoacoustics.............................................................................................................. 180 23.3 Descriptors for environmental noise.............................................................................. 183 23.4 Sound propagation and basic noise control concepts................................................... 187 23.5 Soundscape.................................................................................................................... 188 23.6 Equations and algorithms............................................................................................... 189 23.7 Reference....................................................................................................................... 190 24 Noise Pollution Sources and Impacts...................................................................................... 191 24.1 Typical environmental noise sources............................................................................. 191 24.2 Noise receivers............................................................................................................... 192 24.3 Noise standards.............................................................................................................. 192 24.4 Auditory effects (hearing impairment) and non-auditory effects of noise.................... 197 24.5 Exposure-response relationships................................................................................... 198 24.6 References...................................................................................................................... 198 25 Noise Prediction Modelling..................................................................................................... 199 25.1 Reasons for modelling.................................................................................................... 199 25.2 Basic modelling concepts............................................................................................... 199 25.3 Noise prediction methodologies.................................................................................... 200 25.4 Computation software................................................................................................... 207 25.5 Large scale model for city noise mapping...................................................................... 208 V.2024.05.10 Page vii Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. 25.6 Methodologies and software limitations....................................................................... 208 25.7 References...................................................................................................................... 210 26 Environmental Noise Management........................................................................................ 211 26.1 Prevention of noise problem.......................................................................................... 211 26.2 Control............................................................................................................................ 212 26.3 Abatement...................................................................................................................... 217 26.4 Noise mitigation measures............................................................................................. 219 26.5 Soundscape.................................................................................................................... 222 26.6 References...................................................................................................................... 223 27 Noise Monitoring and Measurement..................................................................................... 224 27.1 General principles in noise monitoring and measurement............................................ 224 27.2 Methodologies for noise monitoring and measurement............................................... 224 27.3 Instrumentation for noise measurements..................................................................... 228 This copy is issued to Lau Chin Tung 27.4 Measurements for verification purposes....................................................................... 229 27.5 Measurements for powered mechanical equipment (PME) for determination of sound power levels................................................................................................................... 229 27.6 Artificial intelligence on noise recognition..................................................................... 230 27.7 References...................................................................................................................... 230 V. Waste.................................................................................................. 233 28 Waste Source and Classification............................................................................................. 234 28.1 General........................................................................................................................... 234 28.2 Sources of waste............................................................................................................. 235 28.3 Waste classification........................................................................................................ 235 29 Municipal Solid Waste Composition and Properties.............................................................. 237 29.1 Composition................................................................................................................... 237 29.2 Properties....................................................................................................................... 238 30 MSW Management................................................................................................................. 240 30.1 Functional elements of waste management system..................................................... 240 30.2 MSW monitoring............................................................................................................ 240 30.3 Waste management hierarchy....................................................................................... 241 30.4 Integrated waste management...................................................................................... 241 30.5 Life-cycle assessment..................................................................................................... 242 30.6 Economic tools for waste management......................................................................... 242 30.7 Waste management law................................................................................................. 243 31 MSW Source Separation, Collection, and Transportation...................................................... 246 31.1 Source separation........................................................................................................... 246 31.2 Collection........................................................................................................................ 246 V.2024.05.10 Page viii Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. 31.3 Transportation................................................................................................................ 247 32 MSW Reduction and Recycling............................................................................................... 249 32.1 Chain of recycling operation.......................................................................................... 249 32.2 Types of recyclables....................................................................................................... 250 32.3 Recyclables segregation, material recovery facility....................................................... 252 32.4 Recycling process............................................................................................................ 254 32.5 Market and outlet of recyclables................................................................................... 256 32.6 Government support to recycling.................................................................................. 257 33 MSW Treatment...................................................................................................................... 259 33.1 Treatment objectives..................................................................................................... 259 33.2 Mechanical treatment.................................................................................................... 259 33.3 Thermal process............................................................................................................. 260 33.4 Biological treatment....................................................................................................... 263 This copy is issued to Lau Chin Tung 34 MSW Disposal......................................................................................................................... 266 34.1 Landfills........................................................................................................................... 266 34.2 Environmental issues...................................................................................................... 266 34.3 Landfill monitoring......................................................................................................... 268 34.4 Landfill restoration and aftercare.................................................................................. 269 34.5 Landfills in Hong Kong.................................................................................................... 270 35 Food and Yard Waste.............................................................................................................. 271 35.1 Sources of food and yard waste..................................................................................... 271 35.2 Food and yard waste characteristics.............................................................................. 271 35.3 Food and yard waste reduction...................................................................................... 272 35.4 Collection, recycling, treatment, and disposal............................................................... 272 36 Construction Waste................................................................................................................ 274 36.1 Source............................................................................................................................. 274 36.2 Composition and characteristics.................................................................................... 274 36.3 Storage, collection, and transportation......................................................................... 274 36.4 Construction waste charging.......................................................................................... 275 36.5 Reuse, public fill reception facilities, sorting facilities, and recycling............................ 275 37 Hazardous Waste.................................................................................................................... 277 37.1 Source............................................................................................................................. 277 37.2 Classification and characteristics.................................................................................... 277 37.3 Storage, collection, and transportation......................................................................... 278 37.4 Treatment and disposal.................................................................................................. 278 38 Clinical Waste.......................................................................................................................... 279 38.1 Source............................................................................................................................. 279 38.2 Classification................................................................................................................... 279 V.2024.05.10 Page ix Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. 38.3 Storage, collection, and transportation......................................................................... 279 38.4 Treatment and disposal.................................................................................................. 280 39 Sludge...................................................................................................................................... 281 39.1 Source............................................................................................................................. 281 39.2 Characteristics................................................................................................................ 281 39.3 Storage and transportation............................................................................................ 281 39.4 Treatment and disposal.................................................................................................. 282 40 Livestock Waste...................................................................................................................... 283 40.1 Source............................................................................................................................. 283 40.2 Characteristics................................................................................................................ 283 40.3 Collection, treatment, and disposal............................................................................... 283 41 Dredged Mud Sediment.......................................................................................................... 285 41.1 Source............................................................................................................................. 285 This copy is issued to Lau Chin Tung 41.2 Classification and characteristics.................................................................................... 285 41.3 Management, treatment, and disposal.......................................................................... 285 42 Radioactive Waste.................................................................................................................. 287 42.1 Characteristics................................................................................................................ 287 42.2 Classification................................................................................................................... 287 42.3 Source............................................................................................................................. 288 42.4 Collection, transportation, and storage......................................................................... 288 43 Contaminated Site Remediation............................................................................................. 289 43.1 Land and soil................................................................................................................... 289 43.2 Causes and hazards of land contamination.................................................................... 289 43.3 Contaminated fate and transport.................................................................................. 290 43.4 Contaminated site characterisation............................................................................... 291 43.5 Investigation methodology............................................................................................ 292 43.6 Remediation standard.................................................................................................... 292 43.7 Remediation technology................................................................................................ 293 44 Facility Siting and Development............................................................................................. 295 44.1 Facility siting................................................................................................................... 295 44.2 Siting considerations...................................................................................................... 295 44.3 Preferred site identification........................................................................................... 296 44.4 Design, build, and operate (DBO) contract.................................................................... 296 45 Occupational Health and Safety............................................................................................. 298 45.1 Health and safety risks................................................................................................... 298 45.2 Means for up-keeping occupational health and safety.................................................. 299 45.3 Legislations..................................................................................................................... 300 46 References.............................................................................................................................. 301 V.2024.05.10 Page x Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. VI. Water.................................................................................................. 304 47 Water Resources..................................................................................................................... 305 47.1 Hydrological cycle of water system................................................................................ 305 47.2 Types of water system.................................................................................................... 305 47.3 Components of water system........................................................................................ 306 48 Water Quality Standards......................................................................................................... 310 48.1 Beneficial use and water quality requirement............................................................... 310 48.2 Water quality objectives................................................................................................ 310 49 Water Quality Impact Assessment.......................................................................................... 312 49.1 Assimilative capacity and water pollution...................................................................... 312 49.2 Sources of impact........................................................................................................... 314 49.3 Assessment and prediction of impact............................................................................ 316 49.4 Impact prevention and mitigation.................................................................................. 318 This copy is issued to Lau Chin Tung 49.5 Impact monitoring.......................................................................................................... 320 50 Water Quality Monitoring....................................................................................................... 321 50.1 General........................................................................................................................... 321 50.2 Ambient monitoring....................................................................................................... 321 50.3 Specific Monitoring........................................................................................................ 322 50.4 Quality assurance and control........................................................................................ 323 51 Collection, Treatment, Reuse, and Disposal........................................................................... 324 51.1 Objectives of prevention, control, and treatment......................................................... 324 51.2 Pollution prevention methods....................................................................................... 324 51.3 Pollution control and treatment methods..................................................................... 325 52 Policy and Legislation.............................................................................................................. 337 52.1 Policy, strategy, and plan............................................................................................... 337 52.2 Water pollution control related regulations.................................................................. 338 52.3 Total water management............................................................................................... 339 53 References.............................................................................................................................. 340 V.2024.05.10 Page xi Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. List of Tables: Table I-1: Hourly concentration of air pollutants in 2022....................................................................... 3 Table I-2: Atmospheric stability categories............................................................................................. 7 Table I-3: 2019 IAQ objectives for Hong Kong...................................................................................... 13 Table I-4: Change of air pollutants emissions in Hong Kong from anthropogenic sources in tonnes.. 15 Table I-5: Source-oriented models accepted by the EPD..................................................................... 28 Table I-6: Revised Hong Kong Air Quality Objectives............................................................................ 36 Table I-7: VOCs removal efficiencies comparison................................................................................. 41 Table I-8: Spatial scale, spatial representativeness, and applications of air quality monitoring stations.............................................................................................................................................................. 50 Table I-9: Commonly used FRMs/FEMs for gaseous air pollutants...................................................... 52 Table I-10: Examples of continuous emission monitoring (CEM) techniques...................................... 56 Table II-1: Main wastewater pollution control technology and the scope of processing object......... 75 This copy is issued to Lau Chin Tung Table II-2: Examples of waste treatment and control technologies..................................................... 75 Table II-3: SOx and particulate matter emission limits....................................................................... 120 Table III-1: DEP, public, and ACE response time limits....................................................................... 133 Table III-2: Authorities providing advice to the DEP........................................................................... 134 Table IV-1: Sound pressure level of events expressed in Pa and µPa................................................. 175 Table IV-2: Some common sound or noise in terms of µPa................................................................ 175 Table IV-3: Recommended one-third octave bands and.................................................................... 182 Table IV-4: Addition of sound levels................................................................................................... 189 Table IV-5: Typical environmental noise sources in Hong Kong......................................................... 191 Table IV-6: Major sensitive uses as defined in the Hong Kong Planning Standards and Guidelines.. 192 Table IV-7: Types of areas containing NSR.......................................................................................... 193 Table IV-8: Area Sensitivity Rating (ASR)............................................................................................ 194 Table IV-9: Night-time noise limits of general power mechanical equipment................................... 194 Table IV-10: Night-time noise limits of specified power mechanical equipment in designated area 194 Table IV-11: Noise limits of percussive piling..................................................................................... 194 Table IV-12: Noise limits of industrial and commercial activities....................................................... 195 Table IV-13: Noise standards for constructing or decommissioning of designated projects under the EIAO..................................................................................................................................................... 195 Table IV-14: Noise standards for various noise sources as set out in the HKPSG and stipulated under TM-EIAO.............................................................................................................................................. 196 Table IV-15: Comparison of engineering and scientific methods....................................................... 200 Table IV-16: Reference to approved EIA reports for various noise sources....................................... 207 Table IV-17: Models available for noise calculation and prediction................................................... 207 Table IV-18: Noise reduction from quiet construction methods........................................................ 220 Table IV-19: Structure-borne noise reduction from quiet powered mechanical equipment............. 220 V.2024.05.10 Page xii Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. Table V-1: Typical MSW constituents................................................................................................. 237 Table V-2: Recyclables recovered from MSW in 2022........................................................................ 256 Table V-3: Construction Waste Disposal Charging Scheme summary................................................ 275 Table VI-1: WQO for Victoria WCZ...................................................................................................... 311 Table VI-2: WQO for bathing beach and secondary contact recreation subzones............................. 311 Table VI-3: Parameters measured in EPD's Marine Water Quality Monotoring Programme............ 322 This copy is issued to Lau Chin Tung V.2024.05.10 Page xiii Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. List of Figures: Figure II-1: The earth system................................................................................................................ 62 Figure II-2: The water cycle................................................................................................................... 63 Figure II-3: Zones of the oceans............................................................................................................ 64 Figure II-4: The Lithosphere.................................................................................................................. 64 Figure II-5: The scientific method......................................................................................................... 65 Figure II-6: Product life cycle................................................................................................................. 68 Figure II-7: Impact of pollutants on the environment.......................................................................... 69 Figure II-8: Overview of scopes and emissions across a value chain.................................................... 79 Figure II-9: Hong Kong's Roadmap to Carbon Neutrality...................................................................... 80 Figure II-10: United Nations Sustainable Development Goals.............................................................. 98 Figure II-11: Sustainability reporting guidance and standards compared with financial reporting... 104 Figure II-12: Roles of business and communities, governments, and the scientific community....... 106 This copy is issued to Lau Chin Tung Figure II-13: Government-business interactions................................................................................ 109 Figure II-14: The geographical boundary of the PRD DECA................................................................ 121 Figure III-1: The statutory EIA process................................................................................................ 128 Figure III-2: Public participation under the EIA Ordinance................................................................. 129 Figure III-3: A material change to an exempted project..................................................................... 132 Figure III-4: Determination of survey duration................................................................................... 152 Figure III-5: Societal risk guidelines for acceptable risk levels............................................................ 162 Figure III-6: Management and reporting relationship between various parties for EM&A............... 166 Figure IV-1: Refraction of sound waves.............................................................................................. 178 Figure IV-2: Sound pressure level vs frequency.................................................................................. 181 Figure IV-3: A graphic representation of the A and C weighting network.......................................... 183 Figure IV-4: Fluctuating noise profile over time................................................................................. 184 Figure IV-5: Leq profile over time......................................................................................................... 185 Figure IV-6: Illustration of barrier height, source, and receiver......................................................... 188 Figure IV-7: Sound pressure level for various noise sources.............................................................. 191 Figure IV-8: Exposure-response relationships.................................................................................... 198 Figure IV-9: Basic noise modelling concept........................................................................................ 199 Figure IV-10: Statutory controls on noise from various construction activities................................. 214 Figure IV-11: Noise source and path................................................................................................... 219 Figure IV-12: Masking of unwanted sound by a favourable sound.................................................... 222 Figure V-1: Solid waste classification.................................................................................................. 236 Figure V-2: MSW composition............................................................................................................ 238 Figure V-3: Waste management system functional elements flowchart........................................... 240 Figure V-4: Waste management hierarchy......................................................................................... 241 V.2024.05.10 Page xiv Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. Figure V-5: Refuse transfer stations in Hong Kong............................................................................. 248 Figure V-6: Major stakeholders in the chain of recycling operation.................................................. 250 Figure V-7: The plastic coding system................................................................................................. 251 Figure V-8: Modern incineration technology process flow diagram.................................................. 261 Figure V-9: Process diagram of anaerobic digestion plant in Siu Ho Wan, Lantau............................. 265 Figure V-10: Landfill bottom liner and cap system diagrams............................................................. 267 Figure V-11: Example of chemical waste label................................................................................... 278 Figure VI-1: The Water Control Zones in Hong Kong.......................................................................... 310 Figure VI-2: Harbour Area Treatment Scheme................................................................................... 338 This copy is issued to Lau Chin Tung V.2024.05.10 Page xv Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. Introduction Hong Kong Institute of Qualified Environmental Professionals Limited (HKIQEP) was established in 2015 to support Hong Kong’s reputation and position as an international leader in environmental management and ensure the quality of work conducted across the growing environmental field in Hong Kong. One of the key objectives is to develop and maintain a qualification process for environmental professionals in Hong Kong. The qualification process involves two main parts – Professional Assessment (Part I) and Professional Assessment (Part II). Professional Assessment (Part I) is a 3-hour multiple-choice examination covering 6 areas: i. Air ii. Environmental Science, Management & Policy (ESMP) iii. Environmental Impact Assessment and Health Impact Assessment (EIA & HA) iv. Noise This copy is issued to Lau Chin Tung v. Waste vi. Water After passing Professional Assessment (Part I), candidates may apply for HKIQEP Professional Membership. Professional Assessment (Part II) will be arranged for eligible candidates. Candidates who have passed both Professional Assessment (Part I) and (Part II) will be considered for election as Professional Members by the HKIQEP Council. A qualified environmental professional shall demonstrate a high level of environmental knowledge, understand the cross disciplinary nature of environmental management, and possess skills to protect and enhance the environment in a sustainable way. He/she must also behave and conduct his/her work with integrity, adhering to the HKIQEP Values, Code of Ethics, and Code of Conduct. This Study Guide is intended to assist individuals preparing for Professional Assessment (Part I), as well as to serve as a reference for environmental professionals in Hong Kong. This guide consists of six topic areas corresponding to the syllabus for Professional Assessment (Part I). Despite being presented in separate sections, the six topic areas are closely related. The intention of this Study Guide is to refresh and sharpen the readers’ concepts and awareness on topics related to the environment. Therefore, instead of giving a detailed explanation in each area, it is expected that readers already have been exposed at the basic level. Readers are also advised to read the recommended materials at the end of each section and in the Professional Assessment (Part I) syllabus. For more information, please visit our website at www.hkiqep.org. V.2024.05.10 Page xvi Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. Acknowledgement The preparation, review, and revision of this Study Guide would not have been possible without the support of different subject-matter experts. We appreciate the time and effort they spent in developing and reviewing the guide. We would also like to acknowledge the valuable sources from the Hong Kong Environmental Protection Department (EPD) in this study guide content. Specifically, we would like to express our gratitude to the following people for their contribution. Chapter on Air Dr. Vincent T.F. Cheung, FHKIQEP Prof. Alexis K.H. Lau, FHKIQEP Dr. Kenneth K.M. Leung, MHKIQEP Ir S.W. Pang, CChem., CSci, CEng, FHKIQEP, MRSC, MEI, MHKIE Mr. Wilson B.C. Tsui, FHKIQEP, CEMAHK This copy is issued to Lau Chin Tung Chapter on Environmental Science, Management and Policy Dr. Billy C.H. Hau, MHKIQEP, CEMAHK Prof. Alexis K.H. Lau, FHKIQEP Dr. Peter K.K. Louie, FHKIQEP Dr. Jeanne C.Y. Ng, FHKIQEP, CEMAHK Mr. Wilson B.C. Tsui, FHKIQEP, CEMAHK Prof. Wang Tao, FHKIQEP Chapter on Environmental Impact Assessment and Health Impact Assessment Mr. Freeman C.M. Cheung, FHKIQEP, FHKIEIA, CEMAHK Dr. Vincent T.F. Cheung, FHKIQEP Mr. Henry H.Y. Leung, FHKIQEP, FHKIEIA Ms. Clara K.W. U, FHKIQEP, FHKIEIA Mr. David Yeung, FHKIQEP, HHKIEIA Chapter on Noise Ms. Anna Y.M. Chung, MHKIQEP, MHKIOA, MHKIEIA Ms. Grace M.H. Kwok, FHKIQEP, FHKIOA, MHKIEIA Dr. C.W. Law, CEng, MHKIQEP, MHKIOA, MIMechE Ir C.K. Lee, CEng, FHKIQEP, FHKIE, FIMechE, MHKIOA Mr. Alfred Wong, MHKIQEP, MHKIOA, MHKIEIA Chapter on Waste Mr. P.H. Lui, FHKIQEP Professor C.S. Poon, FHKIQEP Mr. Frank Wan, MHKIQEP Professor Jonathan W.C. Wong, FHKIQEP Mr. Steven H.L. Wong, FHKIQEP Chapter on Water Mr. P.H. Lui, FHKIQEP Ir Dr. Anthony Y.W. Ma, FHKIQEP, CEng, C.WEM, CEnv, FCIWEM, MHKIE, MIMechE Coordinator Ms. Sarah W.C. Mak, FHKIQEP, CEMAHK V.2024.05.10 Page xvii Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. I. AIR This copy is issued to Lau Chin Tung I. Air V.2024.05.10 Page 1 Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. I. AIR 1 NATURE OF ATMOSPHERIC POLLUTION 1.1 PHYSICAL STRUCTURE AND COMPOSITION OF THE TROPOSPHERE AND STRATOSPHERE The atmosphere serves as the medium into which air pollutants are released. The knowledge on how it functions is essential in understanding the fate and transport of air pollutants. Temperature, Pressure, Density, Spatial and Temporal Relationships The structure of our atmosphere is often defined in terms of the variations in temperature, pressure, and density with height. Pressure and density are controlled by the concentrations of gases in the air. They drop exponentially with height as the air thins. The temperature structure is controlled by the vertical distribution of gases that absorb UV and thermal-IR radiation. Its gradient defines the layers of our atmosphere – troposphere, stratosphere, mesosphere, and thermosphere. The troposphere and stratosphere are more relevant to air pollution. The troposphere extends to about 8-16 km from the poles to the equator above ground. It can be This copy is issued to Lau Chin Tung broadly divided into background troposphere and boundary layer (extending to ~0.5-3 km above ground) which is most relevant as it is where constant air movement occurs. The stratosphere, which protects us from harmful UV radiation, is also relevant in that ozone depletion is caused by human emissions (e.g., chlorofluorocarbons (CFCs)). Radiation In virtually all atmospheric processes, the energy expended is originally derived from solar radiation. The earth absorbs short-wave solar radiation and emits longer wavelength terrestrial radiation. Clouds, water vapor, and carbon dioxide (CO2) absorb thermal IR radiation, which causes the atmosphere to warm. The air around the earth is not heated directly by solar radiation but by terrestrial radiation and convective heating from the ground warmed by the solar radiation, thereby causing a general reduction of temperature from ground to higher altitude. The differential heating of the earth's surface results in different weather patterns. 1.2 NATURAL COMPOSITION OF THE ATMOSPHERE Typical Concentrations of Common Species in the Natural Background Our atmosphere is a mixture of gases and particulates. Some gases (e.g., nitrogen (N2; ~78%), oxygen (O2; ~21%) and other inert gases (e.g., argon (Ar; ~0.93%), helium (He; ~5 ppm)) in the bottom 10 km are well mixed because of their low loss rates. Others are variable gases with concentrations change in time and spaces. Water vapour, CO2, and methane (CH4) are the most abundant varying gases (about 4-5%, 400 ppm, and 1,850 ppm, respectively). The concentrations of other varying gases are generally low in natural background but are high in urban cities and polluted environment. Typical Concentrations of Common Pollutants in Polluted Environments In 2022, the hourly concentrations of sulphur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), respirable suspended particulates (RSP, PM10), and fine suspended particulates (FSP, PM2.5) in Hong Kong could be as high as the values in Table I-1 on the next page. In general, the concentrations of PM10, PM2.5, SO2, NO2 in Hong Kong are decreasing but O3 is still on an upward trend. Also, although CO has the highest mass concentration, its health concern is no higher than others. V.2024.05.10 Page 2 Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. I. AIR Table I-1: Hourly concentration of air pollutants in 2022 Air Pollutant Concentration (μg/m3) Sulphur dioxide (SO2) 59 Nitrogen dioxide (NO2) 290 Carbon monoxide (CO) 2,390 Ozone (O3) 363 Respirable suspended particulates (RSP, PM10) 150 Fine suspended particulates (FSP, PM2.5) 118 1.3 AIR POLLUTANTS Definitions & characteristics (physical & chemical) This copy is issued to Lau Chin Tung Air pollutants are airborne substances that could threaten the health of people and animals, and harm vegetation, structures, and the environment. They can be gaseous air pollutants and particulates and are classified as primary and secondary. Primary air pollutants (e.g., CO, SO2, NOx, VOCs, particulate matters) are those which are emitted to the air directly from the sources. Secondary air pollutants are those formed in the atmosphere by chemical reactions (e.g., acid-base reaction, oxidation, photochemical reaction) among primary air pollutants known as “precursors”. Examples include sulphates, NO2, O3, peroxyacetyl nitrate, etc. Not being directly emitted in the exhaust gas streams, secondary air pollutants are usually more difficult to control. Particulates Particulates are a complex mixture of solid particles and aerosols (liquid particles) of a wide range of chemical, size, and physical characteristics. Particulates may also carry other pollutants dissolved in or adsorbed to their surface. Some common particulates include road dust, soot, oily fumes, nitrates, sulphates, organic aerosols, metallic compounds, dioxins, polycyclic biphenyls, pesticides, asbestos (e.g., chrysotile, crocidolite, actinolite, tremolite, anthophyllite), etc. Particulates can also be viable (e.g., bacteria, spores, pollens) and they are also called bioaerosols. Particles with aerodynamic diameters of about 75 µm or less can suspend in air for prolonged periods and are called total suspended particulates. Those with 10 µm or less in diameter, which are known as respirable suspended particulates or PM10, are sufficiently small that they can penetrate to the thoracic region. The fine fraction with 2.5 µm or less is referred as fine suspended particulate or PM2.5. They may even deposit in the smaller conducting airways and alveoli. Other than primary particulates, secondary particulates may be formed in the air and they can make up quite a significant percentage of PM2.5. Ammonium sulphates, nitrates, and secondary organic aerosol (SOA) are their major components. Gaseous pollutants Hundreds of different gas-phase substances are emitted to the atmosphere from both natural and anthropogenic sources. Common gaseous air pollutants include CO and CO2, sulphur oxides (SO2 and SO3), nitrogen oxides (N2O, NO and NO2), O3 and photochemical oxidants, NH3, CFC, methane, volatile organic compounds (VOCs, which are organic chemicals with high vapour pressures at ambient temperature, such as benzene, toluene, ethylene, formaldehyde, etc. and many of them are precursors of photochemical smog). Most gaseous pollutants, other than CFC and other stable air pollutants, are likely degraded chemically before reaching the stratosphere. V.2024.05.10 Page 3 Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. I. AIR Toxic air pollutants Toxic air pollutants (TAP) (or hazardous air pollutants (HAP)) are those air pollutants that are known or suspected to cause serious and irreversible adverse health or environmental effects. In the USA, 187 HAPs have been designated for protection of public health. Among them, 30 TAPs are identified as posing the greatest potential health threat in urban areas. They include a) Metals (As, Be, V, Cr, Pb, Mn, Hg and Ni) and their compounds b) Organics: acetaldehyde, acrolein, acrylonitrile, benzene, 1,3-butadiene, chloroform, dioxins, 1,3- dichloropropene, ethylene dichloride, ethylene oxide, formaldehyde, hydrazine, methylene chloride, propylene dichloride, quinoline, 1,1,2,2-tetrachloroethane, tetrachloroethylene, trichloroethylene, vinyl chloride and persistent organics (i.e., dioxins, polycyclic aromatic hydrocarbons (PAH) or polycyclic organic matter (POM), and hexachlorobenzene) Threshold and non-threshold pollutants The pollutant level below which no ill effects are observed is called the threshold level. The typical example of air pollutants with a threshold is CO. For these air pollutants, an exposure level, which is known as “no observed adverse effect level (NOAEL)” that at which there are no statistical increases in the frequency or severity of adverse effects can be identified. Other air pollutants (e.g., PM2.5, PM10, This copy is issued to Lau Chin Tung O3), however, are found to have no or very small health thresholds. A risk assessment approach is taken for determining the tolerable or acceptable levels: a) Risk ≦10-6: acceptable b) Risk between 10-4 and 10-6: best effort, with the consideration of cost, technical feasibility and other factors, should be taken to reduce the risk c) Risk > 10-4: not acceptable Radionuclides Radioactivity is a form of radiation that is emitted when a radioactive element decays emitting energy (γ-ray, α-, β-particles) in an attempt to gain nucleus stability. The use of nuclear energy, including power generation, nuclear fuel processing, medical uses, nuclear weapons, can be the sources of radioactive pollution. Releases of radioactivity (e.g., radionuclides include I-131, Sr-90, Pu239) during major disasters (e.g., fallouts of the Three Miles Island, Chernobyl, and Fukushima reactors) are major concerns. A more important radioactive pollution is the elevated indoor levels of radioactive radon (Rn-222) gas. It is a colourless, odourless noble gas produced from the radioactive decay of radium, which is naturally found in common minerals, such as granites. Its progenies are radioactive particles with long half-lives and may stay in the lung and respiratory system for even more prolonged period. Due to the extensive use of granites as building materials, Hong Kong’s indoor radon levels could be high, especially in poorly ventilated premises. Biological contaminants The common biological contaminants include pollens, moulds, bacteria, or viruses that adversely affect health. They are a major concern indoors, but the spread of biological contaminants can also be severe in poorly ventilated tall building clusters, e.g., SARS and COVID-19 virus episodes. Odour Odour is our perception of smell. It is induced by inhaling airborne volatile organic or inorganic materials. Most common odorous substances include hydrogen sulphide (H2S; rotten egg smell), O3 (fishy smell), NH3 (sharp pungent smell), carbon disulphide (CS2; ether like smell), products of decomposed proteins, phenols, and some petroleum hydrocarbons. The concentration of odour is determined by olfactometry, i.e., by human noses (and in some cases, by chemical methods and electronic nose) with the odour threshold taken as 1 odour unit (ou). V.2024.05.10 Page 4 Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. I. AIR 1.4 PHYSICAL AND CHEMICAL POLLUTANT PROCESSES 1.4.1 Transport, dispersion, dilution, transformation, scavenging, and atmospheric lifetimes The dispersion of air pollutants is the result of transport of the air pollutants away from the sources by air motion or wind and dilution or mixing by diffusion due to atmospheric turbulence and concentration difference. There are different scales of air motion which affect air pollutant transport and dispersion in different manners: a) Global and synoptic scales: wind patterns are set up due to differential heating of the earth's surface by solar radiation (e.g., at the equator and polar regions), rotation of the earth and the difference between the heat capacities of land and ocean masses b) Mesoscale: wind patterns develop because of the regional or local topography (mountain ranges, water bodies, deserts, forestation, etc.) c) Microscale: wind patterns are created by local temperature and turbulence conditions This copy is issued to Lau Chin Tung During dispersion and dilution, the air pollutants may be removed from the atmosphere. Chemical reaction, in particular, oxidation, is a prime removal mechanism. The important naturally occurring scavenger is the hydroxyl radical, which is formed by reaction of water with free oxygen atoms created by the photochemical breakdown of tropospheric ozone. It oxidizes many air pollutants to products (e.g., sulphuric acid, nitric acid) that can be brought down from air by precipitation. Also, humidity and rainfall (or precipitation) play important roles in removing air pollutants, in particular, the particulate matters, by (i) “in-cloud” process: in which particulates in the air act as nuclei for the condensation of rain droplets and when the droplets become heavy enough, they will precipitate; and (ii) collision with raindrops that dissolves or bring the pollutants to the ground. The place where the air pollutant is removed from atmosphere is called the “sink”. Sinks include the soil, vegetation, structures, and water bodies, particularly the oceans, as well as the substances that react and remove the air pollutant from the air (e.g., NO for O3). The time it takes for half of the quantity of pollutant emitting from a source to disappear into its various sinks is referred to as the “half-life”. Most pollutants have a short half-life (from hours to days), but CFCs and other chemically stable compounds can have half-lives from tens of years to over 100 years. 1.4.2 Meteorological effects: Influence of solar radiation and wind fields, lapse rate and stability conditions The concentrations of air pollutants are affected by winds, temperatures, vertical temperature profiles, turbulence, solar radiation, clouds, rainfall, and relative humidity. These meteorological parameters are influenced by both large- and small-scale weather systems in which the solar radiation and local topography play important roles. Large scale weather systems are controlled by vast regions of high and low pressure. The differential heating of earth’s surface by solar radiation and unequal absorption creates a dynamic system with differences in barometric pressure. Air flows counter clockwise and vertically upward in low pressures systems (cyclones) in the north hemisphere and, in the opposite in high pressure systems (anticyclones). The rising air in low pressure systems, together with the associated cloudy skies, fast surface winds, and low penetrations of solar radiation help disperse air pollutants. On the other hand, the sinking air, slow surface winds, cloud free skies, and high penetrations of solar radiation associated with high pressure systems favour the accumulation of air pollutants. V.2024.05.10 Page 5 Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. I. AIR Wind is the most significant meteorological element that controls day to day variation of air pollution over a city. It is characterised by both wind speed (velocity) and direction. It affects the dispersion in the way that the: a) Air pollutant concentration is inversely proportional to the wind speed b) Mechanical turbulence, which is created by wind, increases with wind speed c) Plume rise of the emissions decrease with wind speed In general, wind speed increases with height above the ground level (u(z) = u(z0)(z/z0)p ; p an exponent varying with the surface roughness and stability from about 0.1 (open country) to about 0.4 (urban area)), as frictional drag, which depends on surface roughness decreases. Wind direction depends on the prevailing air flow in the general global circulation, cyclonic and anticyclonic flows associated with migrating low pressure and high-pressure systems, monsoons, and local topography. Wind direction and its variability have significant effects on air quality. The irregular air movements over the main current of wind flow are called turbulent eddies. They are produced by: a) Mechanical turbulence, which is induced by wind moving over or around surfaces or structures This copy is issued to Lau Chin Tung and increases with wind speed and surface roughness b) Thermal turbulence, which is larger than mechanical eddies and resulted from the heating and or cooling of air and the convection of heat near the earth’s surface. Turbulence, other than the building downwash effect, enhances atmospheric mixing and helps air pollution dispersion Vertical air motion is equally important in air pollutant dispersion as it affects the height of the air layer where dispersion can take place and the amount of air available for air pollutant mixing. The change in temperature with elevation is key parameter that affects the vertical dispersion. Under ideal condition, the rate of temperature decrease with height (lapse rate; dT/dz) equals to the adiabatic lapse rate (Γa) of 9.8oC/km. The actual rate of temperature change with elevation is the ambient lapse rate or environmental lapse rate. If the lapse rate is greater than Γa, i.e., superadiabatic, air becomes buoyant and such condition is characterised as unstable atmospheric condition. This is usually common during daytime conditions when the sun heats the ground surface. Because of the greater degree of turbulence, it provides a good dispersion condition for air pollutants. On the contrary, stable atmospheric conditions which is unfavourable for dispersion occur if the lapse rate is less than Γa, i.e., subadiabatic. Neutral atmospheric condition occurs if the lapse rate equals to Γa. In extreme cases, the lapse rates increase with height and such atmospheric conditions are temperature inversion which is most susceptible to high and serious air pollution due to the suppression of the vertical mixing of air pollutants. Temperature inversions include the following: a) Radiation inversion: Resulting from the radiative cooling air near the ground surface during calm and cloud-free nights. Air pollution episodes in Hong Kong during wintertime (e.g., 19.1.2003, 31.12.2003) could be associated with radiation inversion. b) Subsidence inversion: Occurs within high-pressure system over large geographical areas. The descending air compresses and warms up an air layer aloft. In Hong Kong, subsidence inversions may also be formed as a result of air subsidence associated with tropical storms several km away (e.g., near the Taiwan Strait). The air pollution episode of Hong Kong in 2.11.2003 is an example. V.2024.05.10 Page 6 Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. I. AIR c) Frontal inversion: The cold, dense air of the cold front forces air in warm area to rise. Based on meteorological conditions and time of day, the atmospheric stability can be grouped into 6 categories, namely, A (very unstable), B (unstable), C (slightly unstable), D (neutral), E (stable), and F (very stable). The different categories and their relevant parameters are shown in Table I-2 below. Table I-2: Atmospheric stability categories Day Night Wind speed at Incoming solar radiation Thin overcast 10 m/s Strong Moderate Slight ½ low cloud ⅜ cloud 6 B D D D D The point at which the air parcel cooling at the dry adiabatic lapse rate intersects the ambient temperature profile represents the mixing height (MH), which is the height of the vertical volume of air above the earth’s surface where relatively vigorously mixing and pollutant dispersion occurs. MH varies both diurnally and seasonally, usually greater during afternoon or in summertime. It is also affected by topography and macro-scale air circulations, e.g., high pressure systems. The plumes from point sources (stacks) rise buoyantly because they are hotter than the surrounding air and that they exit upward with a vertical velocity. Plume rise, therefore, depends on the difference of stack and ambient temperature (Ts – Ta) and exit velocity (vs), and stack downwash (downdraught) occurs if vs < 1.5 x wind velocity. The vertical and horizontal air motions also influence the behaviour of plumes, such as: a) Looping plume, which occurs in highly unstable conditions associated with strong turbulences and rapid overturning of air b) Fanning plume, which occurs in stable conditions which discourage vertical motion without prohibiting horizontal motion c) Coning plume, which is characteristic of neutral or slightly stable conditions d) Lofting plume, which occurs when the plume is above an inversion e) Fumigation, which occurs when the plume is released just under an inversion layer and serious air pollution situation can develop Topography also influences air pollutant levels. For example, the area near the seashore may be affected by sea land breezes, which are resulted from the differential heating and cooling air over land and sea surface. The circulation sea land wind patterns may allow air pollutants to be recirculated and accumulated. In Hong Kong, sea land breezes are significant to the low-level wind convergence in early afternoon in western part of the territory in autumn and winter. The air pollution episode in 14.2.2004 is an example. The other topographical effect includes the valley mountain breezes resulting from the differential heating and cooling of air on the mountain slopes. Valleys are more susceptible to air pollutant accumulation and for this reason, Hong Kong has been requiring the use of gaseous fuel only in the Sha Tin area. V.2024.05.10 Page 7 Copyright @ 2024 Hong Kong Institute of Qualified Environmental Professionals Limited. All Rights Reserved. I. AIR Urbanization is another factor that could influence the local meteorology and air pollution levels. In urban cities, concrete buildings absorb heat during the day and radiate it at night, creating a heat island, which sets up a self-contained circulation for the air pollutants. The urban heat island effect causes an increase in the temperature gradient between the land and sea surface, resulting in a strengthening of the sea land breeze circulation in the Hong Kong and PRD region. Urban cities are often suffering from street canyon effects. Street canyon is a relatively narrow street with tall, continuous buildings on both sides. Those with aspect ratios (height to width) greater than 2 are deep canyons in which air pollutants are likely be trapped and recirculated. It is a reason why Des Voeux Road and Queens Road Central in Hong Kong have significantly higher air pollutant levels than the nearby Connaught Road which has about 5-10 times more traffic. 1.4.3 Spatial and temporal variation of air pollutant concent
