Tài liệu Environmental Technology Series-Part 2: Approaches for Consideration in Formualating Environmental Control Strategies pptx

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WHO/PEF/GETNET/93.2-8 DISTR: LIMITED ENGLISH ONLY #4 SCFL RQ : ore ì | ASSESSMENT OF SOURCES OF Air, WATER, AND LAND POLLUTION

A Gutbe 10 Rapip Source INVENTORY TECHNIQUES AND THEIR Use IN FORMULATING ENVIRONMENTAL

CONTROL STRATEGIES

Part Two:

APPROACHES FOR CONSIDERATION

IN FORMULATING ENVIRONMENTAL

CONTROL STRATEGIES

BY

ALEXANDER P, ECONOMOPOULOS

Democritos University OF THRACE

Wonkrip HEALTH OrGANIZATION, GENEVA, 1993

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CONTENTS

PART Approaches for Consideration in Formulating Environmental Control Strategies

Preface

Introduction

Systems Analysis in Environmental Management Management of Air Pollution

Management of Water Pollution Management of Solid Wastes

Appendix | Environmental Quality Guidelines

Appendix II UN Classification of Industries and Services

Appendix I Conversion Factors and Selected Material Properties Appendix IV List of Abbreviations

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PREFACE

Environmental management is often referred to as an art rather than as a science The past twenty years has seen considerable progress toward re- vising this image Numerous examples can be cited which show that proper planning can significantly reduce the impact of human activities upon the environment (Economopoulos, JAPCA 37:8, 1987) The difficulties in formulating sound environmental management programmes, are especially pronounced in developing countries, and there is a need for practical tools that are suitable for widespread implementation and that permit

the standardization of the critical initial stages of the planning process, This book attempts to address these requirements

Some years ago, WHO published a book entitled Rapid Assessment of Sources of Air, Water and Land Pollution (WHO, offset publication No

62, 1982), which focused primarily on the source inventory aspects of the management process Translated into several Janguages, it has been widely distributed and the procedure described has been the subject of numerous training courses The Rapid Assessment procedure has been found

particularly useful in developing countries in the design of

environmental control strategies and policies using relatively modest resources

More recently, WHO updated and expanded the Rapid Assessment techniques by publishing a book entitled "Management and Control of the Environ- ment" (WHO/PEP/89.1) This book strengthened the inventory portions, provided comprehensive lists of control options for each kind of air or

water pollution source, and introduced some easy to use air and water quality models This book, as well as its predecessor, has been found

valuable in developing countries, and two of its reprints have already been exhausted

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Approaches for Consideration in Formulating Environmental Control Strategies iii

In 1991, WHO initiated the Global Environmental Technology Network (GETNET), which had as its prime objective the strengthening, at the

focal level, of education and training materials on environmental

pollution control technologies This book, which succeeds a previous

publication entitled "Management and Control of the Environment", is linked to the GETNET activities and will hopefully be widely used by developing countries to assess their environmental conditions and lead to making the environmental management process more of a science than an art

The rapid assessment procedure is most useful in making an initial ap- praisal of the sources and levels of emissions from an area that has little or no previous pollution load data It is also useful in select-

ing priority areas to conduct more extensive monitoring surveys; for conducting case studies as part of public health programmes directed at pollution control; and for formulating pollution control policies and regulations for national environmental health activities

Part One of this book updates the rapid pollution assessment factors and

introduces air, water and solid waste inventory and contro] models It describes how to initiate a study, including how to organize study teams, how to define study areas, and how to collect, cross-check, organize and process field data so as to generate air, water and solid waste

inventories, and, how to produce relevant reports to present to decision

or policy makers The necessary models and data for conducting air, water and solid waste inventories, for defining alternative control

measures, and for assessing the pollution load reduction effectiveness

of the latter are provided in Chapters 3 to 5 Study organization and implementation aspects are discussed in Chapter 6

Part Two of the book deals with environmental management problems and

describes how to assess the current quality of air and water and how to identify land pollution problems; it also describes how to formulate

alternative control strategies, how to evaluate their effectiveness and

how to define high priority action programmes The systems analysis approach, which sets the stage in the remainder of this book for the development of rational pollution abatement strategies, is presented in Chapter 7 Management approaches for urban and rural air pollution

problems and selected air quality models are presented in Chapter 8, and for water pollution problems and selected water quality models in

Chapter 9 Management approaches for municipal solid wastes and

hazardous substances are discussed in Chapter 10

While the focus of this new book is on the revision of the rapid assessment process, the model application techniques for air, water and solid wastes are greatly expanded There is considerable discussion of various Management approaches to consider once an environmental assessment of

the area has been completed The listing of all possible control and

prevention strategies would, obviously, constitute an extremely ambitious, if not impossible task Accordingly, the management

approaches described in Chapters 8 to 10 are to be regarded as

suggestions for the development of an environmental control strategy for

an area Many of these techniques to reduce pollution have proven to be very powerful and should be given serious consideration in problem

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iv Preface

of the expanded tools and data for conducting or updating their emission

inventories and then give serious consideration to the approaches suggested herein WHO, through the GETNET and its many experts from aT] fields of environmental technology in over 65 countries, can provide assistance to developing countries in interpreting the results of the

rapid assessment and in the selection of management approaches

Work on this book started before its predecessor, "Management and

Control of the Environment", was published, mainly in the form of research addressing the Tack of suitable models, for the purposes of the present methodology The content was discussed at a consultation held in Geneva in June 1991 The first draft was reviewed during a meeting held in Athens in July 1992 Mr G Ozolins, Manager, and Mr D L, Calkins, Scientist, both from Prevention of Environmental Pollution, Environ-

mental Health Division, WHO Geneva, provided the necessary impetus for the writing of this book and their support and advice throughout the preparation period is gratefully acknowledged

Thanks are also due to Mr 6 0zolins, Dr D Mage, and Mr D, Calkins, from the Prevention of Environmental Pollution, Environmental Health Di- vision, WHO Geneva, for reviewing the source inventory and the section

on air pollution management and for drafting most of the preface; to Dr

R Helmer, from the Environmental Health Division, WHO Geneva, for reviewing the water pollution management; to Mr P Economopoulos, from

the Association of Communities and Municipalities of Attika Region, for

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INTRODUCTION

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vi Approaches for Consideration in Formulating Environmental Controt Strategies

1 Introduction

Environmental pollution affects the air we breathe, the water we drink and the food we consume It also affects the production of food, the

general quality of our surroundings and may pose a risk to our health

and well-being Control of environmental pollution is necessary in almost al] communities and countries to protect the health of the popu- Tation The important question to be answered in each situation, is which pollutants should be controlled, in what way, and to what extent

This book recommends the systems analysis approach and the simplification of analysis procedures in environmental management, both of which can be particularly effective in the analysis of existing

problems and in the synthesis of control strategies:

The systems analysis approach, which is introduced in Chapter 7 of Part

II, is systematically followed in Sections 8.1, 9.1, and 10.1 dealing with the management of the air, water and land pollution problems The essence of this approach lies in the analysis of existing problems and the identification of the most critical ones, in the setting of definite pollution control objectives and

in the development of effective strategies to meet those objectives The above requires the capability to conduct source

inventories, to assess the impact of the released loads into the receivers, to define major control alternatives and to analyze their environmental, economic, and implementation consequences

The systems analysis approach offers the important practical advantages of high cost-effectiveness and fast implementation, and its results can be impressive indeed It creates however, particularly demanding analysis requirements, which have to be simplified

and addressed through special tools and procedures, if it is to be practical and widely used

The simplification of analysis procedures down to practical, and yet meaningful levels, while maintaining at the same time a highly integrated environmental management approach in relation to air, wa-

ter and land pollution, has been the major challenge in the writing of this book,

The environmental management requirements were addressed through

the following procedure: complex problems were decoupled into a

series of much simpler ones; inventory and control models, as well

as ambient quality models, capable of providing solutions in an

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Introduction vii

The selection of analysis tools defines to a large extent, on the

one hand the magnitude of resources required (manpower, skills,

study duration, etc.), and on the other hand the reliability of the management results The need thus arises for the screening of

available models for the purpose of carefully balancing issues

such as the accuracy and the reliability of predictions against the importance and relevance of results, ease-of-use and data

requirements, or inter-model-compatibility As ready, off-the- shelf, models meeting the above requirements did not always exist,

some models had to be adapted and expanded (e.g the ECE CORINAIR

model for traffic fuel consumption and air emission calculations), while several new models had to be developed (e.g the air, water and solid wastes inventory and control models presented in Sections 3.2.2, 4.2.2 and 5.2.2, as well as all air quality models

presented in Section 8,2),

For most developing nations, where environmental problems are often critical and available resources scarce, environmental management

approaches based on the best available control technology tend to be too

expensive, while those relying on the imposition of selective controls

through local inspectorate decisions and public opinion feedback, tend to be unworkable (lack of inspector skills and other infrastructure

requirements, long response times, etc, see Section 7.2.) The alternative systems analysis approach for environmental management ,

followed in this book, is believed to be better suited for developing

nations as it offers a practical procedure for formulating cost-

effective strategies, targeted at selected critical problems, as well as

detailed action programmes, which facilitate Strategy implementation It is thus hoped that the described procedure can contribute to better health and environmental quality protection, to conservation of valuable resources, and to unobstructed development in a rational and sustainable

manner

Designed as a work-book, this publication contains all the information

required to analyze the current situation and to develop adequate

management approaches, and additional information, such as conversion factors that facilitate the task However, the measures derived through the recommended procedure, especially the complex and expensive ones, should not be regarded as final or as suitable for direct implementation, but rather as promising, high potential candidates which

require further examination through more detailed feasibility studies

Making assessments of environmental pollution and devising control strategies should not be viewed as a one-off effort, but rather as an on-going process After an inventory of pollution loads has been made in a given area or country, it will need to be kept up-to-date and its accuracy improved Similarly, control strategies will need to be reviewed as to their effectiveness and cost, while the efficiency of implemented measures will need to be monitored and compared with predictions, so as to provide guidance for the future Assignment of these follow-up responsibilities to a specific government department is necessary, but the involvement of other government experts who would provide data and support to the total effort should be encouraged and stimulated Examples of the latter are environmental and public health

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viii, Approaches for Consideration in Formulating Environmental Control Strategies

planning specialists, statisticians with knowledge of industrial and

other economic activities, etc This network of experts could, in a

spirit of fruitful cooperation, develop into a highly competent planning body with far reaching impact

The environmental management techniques described in this book can be

used at different levels: municipal or local, provincial or state, and national At the local and regional level, the management results can be used for addressing the pollution problems in an effective way At the

national level, management plans from various regions can be combined and used in the formulation of a national environmental management

policy, which offers notable advantages such as:

# Rationalization of allocated government funds for protection of the environment through clear national priorities;

# Improved implementation through appropriate distribution of relevant responsibilities among the central and local authorities As a general rule, the implementation of relatively simple measures affecting numerous smal} local sources can best be handled by local authorities, while that of complex measures affecting larger areas, by central government services An example of a measure suitable for implementation by local authorities is the Inspection and

Maintenance of central heating furnaces, and of measures suitable

for implementation by central government are the changes in the fuel type or quality, or the setting of vehicle emission standards Competent central government control and coordination is highly desirable in relation to the formulation, implementation and follow- up of national environmental plans;

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7.1 7.2 7.3 7.4 CHAPTER 7 SYSTEMS ANALYSIS IN ENVIRONMENTAL MANAGEMENT Introduction

Existing Environmental Management Approaches

Environmental Management Through a Systems Approach Bibliography

7-1

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7-2 Approaches for Consideration in Formulating Environmental Control Strategies 7.1 Introduction

The particular system, upon which local and regional authorities base their air, water and Tand pollution control programmes, is affected by many factors, such as nature of the pollution problems, the natural

adherence to techniques used in the past, the enforcement and inspection

infrastructure, the legal environment, the sensitivity of the people,

the priority of environmental issues in political thinking, and, last

but not least, the availability of resources for protection of the environment

Any particular system can be considered effective if it works within the local context and manages to satisfy the environmental sensitivities of

the people by bringing into proper balance the needs for development on

one hand and the allocation of resources for environmental protection on the other

The choice of management system to be used by a developing country has a number of far reaching implications for cost-effectiveness and enforce-

ability of the resultant contro] strategies among other things It 1s

thus fitting to discuss in the following sections some of the systems

used by developed countries, and to outline an approach which appears to best serve the needs of developed countries and which is followed in this book

7.2 Existing Environmental Management Approaches

Most developed countries, having faced acute pollution problems much earlier than the rest of the world, some of them since the dawn of the industrial revolution, have had ample time for developing effective

pollution control approaches

The control approaches used by the developed countries vary, often sig-

nificantly, from country to country as they are affected by the multi- tude of factors mentioned in Section 7.1 Despite these differences, they have two fundamental mechanisms in common:

1 Public Pressure Feedback for Environmental Action

Environmental problems are bound at some stage to cause public con- cern and increased pressures for improved controls In response to such pressures the pollution inspectorates tighten the measures until the situation is brought back to normal

This mechanism is apparently cost-effective, as measures are taken only up to the degree required However, the response is slow, as it takes time for results to appear, and the entire mechanism is better

suited to address pollution problems of Tocal rather than global

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Systems Analysis in Environmental Management 7-3

As far as developing countries are concerned, implementation of

similar approaches is difficult since a key prerequisite for their success is the existence of a highly competent inspectorate

infrastructure, as well as safeguards for the unbiased and smooth

operation of the entire system

2 The Best Practical Control Technology Principle

Strategies based on this principle clearly entail the highest costs, as the best practical control technologies are always implemented, even when this is not directly justified by the local pollution problems They provide however the possibility of swift action, as relevant control programmes are drafted by central planners and become automatically effective over an entire region or country Moreover, transboundary and global pollution problems are best served by these environmentally responsible practices

Approaches of this type, where highly competent central planners define the action programmes, are among the easiest to implement, and

as such they are suitable, in this respect, for developing countries The high cost however, of the resultant environmental programmes may not represent the best allocation of the often limited resources in the developing world

7.3 Environmental Management Through A Systems Approach

A modern environmental management approach, suitable for widespread use,

should be able to produce pollution contro] strategies, which are cost-

effective for the purpose intended, as well as enforceable through the existing government infrastructure As discussed below, both of these requirements can be satisfied by the formulation of detailed action

programmes by competent groups of central planners through systems analysis

The term detailed action programme is used in this book with the un-

derstanding that it comprises specific technical or institutional measures, rather than legislative stipulations and effluent or emission standards An example of such specific measures would be the addition of

multicyclones to the kiln of a lime manufacturing plant, or the addition of a secondary treatment facility for the effluents from a fruit

cannery, or the lowering of the sulfur content of the residue fuel oil to a particular level Such specific measures stand a good chance of

being implemented if properly channelled through existing government

services (Economopoulos, 1987)

The entire approach presented in this book is in line with the above

prerequisites Indeed, the appointed study team is entrusted to identify

the major pollution problems over an entire study area and to develop a

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7-4 Approaches for Consideration in Formutating Environmental Control Strategies

SYSTEMS ANALYSIS OBJECTIVES OPTIMUM SOLUTION IMPLEMENTATION ASSESSMENT OF RESULTS

Figure 7,3-1 Diagram of a systems analysis approach

Definition of the strategy objectives: This is the first major task in

the systems analysis procedure as shown in Figure 7.3-1 In our case the general objective is to safeguard human health, and the

environment in general (e.g maintain an acceptable quality of

fresh water) In the practical context of environmental studies, this implies conformity to specific environmental quality standards A list of selected WHO guidelines for the quality of air and water is given in Appendix I Observance of these standards is the prime objective of most environmental management studies

Occasionally, other objectives may have to be set For example, in

the case of lakes, one may define as one of the objectives of an

environmental strategy the maintenance of a ake in an

oligotrophic state, or the prevention of the development of

eutrophic conditions The terms Oligotrophic and Eutrophic are generic parameters rather than concentrations and they char-

acterize in this case in a more meaningful way the general situa-

tion of the entire lake ecosystem In the case of toxic (black

listed) substances in liquid wastes, the objective may be to re-

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release, may also be set as objectives for particular studies, but the analysis of relevant subjects is outside the scope of this book

Definition of the criteria of effectiveness: This is the second major task in the systems analysis procedure The criteria need to be compatible with the objectives, so as to enable the user to know when the objectives are fulfilled or how effective a particular set of measures is towards meeting the objectives Based on the above, the criteria of effectiveness are normally the pollutant concentrations in the ambient air or in the water receivers The latter explains the paramount importance of air and water quality

models in environmental management studies, as their prime task is

to translate the released pollutant loads, obtained through tha source inventories, into pollutant concentrations

Criteria of effectiveness may occasionally be other than concentrations In the case of lakes for example, the criterion of effectiveness may be measured through the normalized phosphorus

loading (see Section 9.2.2) It should be noted that in this case the water quality model is used to provide the objective (critical normalized Take loading) rather than to evaluate the criterion of effectiveness In the case of toxic (black listed) substances in liquid wastes, the criterion of effectiveness may be the reduction

in the released loads The latter is obtained directly through the

source inventory model, without the need for any water quality model Other parameters, such as the risk of an accidental major release, may also be used as criteria of effectiveness of a

particular strategy, but these are outside the scope of this book

Application of appropriate air and water quality models: This is the

third major task in the systems analysis procedure, allowing users

to identify the nature and severity of existing pollution problems

and to test the effectiveness of alternative control measures Naturally, the end output from the application of such models should be compatible with the study objectives that have been set and with the accepted criteria of effectiveness This way the user can determine under what conditions the objectives are met and to

measure the effectiveness of any particular strategy

Two types of relevant models are provided in this book One type allows assessment of the released loads under current conditions or under selected control measures (see Sections 3.2, 4.2, and 5.2), while the other employs the source inventory data to compute the pollutant concentrations in the ambient air or in the water receivers (see Sections 8.2 and 9.2)

In the choice of measures and in the formulation of strategy sce- narios the existing constraints have to be considered if the results are to be practical, acceptable and enforceable Such constraints may reflect difficulties in enforcing certain measures, excessive negative impacts on local manufacturing segments,

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7-6 Approaches for Consideration in Formulating Environmental Control Strategies

Testing of control options and analysis of sensitivities: This is the fourth major task in the systems analysis procedure and consists of the systematic screening of all available control options and evaluation of their relative effectiveness from the environmental, cost and enforceability point of view In this way, the sensitivity of the overall] system response to various alternative decisions, as well as to various levels of strictness of selected particular measures (e.g the reduction of the sulfur content in

heating oi1) can be established

The end product of this exercise can be a table listing the effectiveness of selected measures against the set objectives and possibly the assignment of priorities to such measures To facilitate this task, selected source inventory and environmental qual-

ity models are provided in Chapters 3 to 5 and in Sections 8.2 and

Formulation of optimum strategies: This is the fifth major task in the

systems analysis procedure and comprises the selection of a set of

enforceable measures, through which all the set objectives are met with the least cost As explained above, the formulation of rigourously optimized strategies is outside the scope of this book as it necessitates, among other things, more detailed technical analysis, as well as a comprehensive economic analysis for each alternative measure

However, despite the lack of such technical data, one can

formulate rational and truly effective strategies through common

sense, experience, and by observing some simple rules such as assigning high priority to inspection and maintenance programmes (e.g inspection and maintenance of industrial boilers, domestic

furnaces and traffic vehicles), opting for fuel type and quality improvements for small and medium size combustion sources, rather than for the installation of control equipment, or isolating the

largest single sources, as well as those held directly responsible

for environmental quality violations The above go a long way

towards defining truly effective and near optimum management schemes More detailed discussion on the present topic and analysis of specific measures is provided in Chapters 8 to 10 For the formulation of rational strategies two basic approaches

exist, and the choice of the most appropriate one depends each

time on whether suitable air or water quality models are available for the problem under consideration:

If appropriate models are not available, the scheme

illustrated in the diagram of Figure 7.3-2 could be used In this, air or water quality monitoring provides information

on the initial Tevels of pollution If the allowable levels are surpassed, control strategies comprising simple and enforceable measures are formulated and implemented, and

their ultimate efficiency and sufficiency is judged from the environmental improvement achieved, as measured through the on-going air or water quality monitoring If the set objectives are not met, supplemental strategies are formed

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Systems Analysis in Environmental Management 7-7 and implemented and this process continues until the situation is brought under control

Control Approaches Inventor Source

| mm Ì

Figure 7.3-2 Feedback approach for strategy formulation

The strategy formulation process can be assisted each time

through source inventories, which yield the pollution loads

released, identify the major sources, and provide assessment of the impact of alternative control options on the pollu-

tion loads released A valuable picture of the existing sit-

uation is thus produced, which can be used by experienced planners to enhance their strategies Sections 3.2 and 4.2

provide suitable models and data for this purpose

In the above approach, the strategy formulation is based on the planners’ intuition and experience, rather than on a rigorous analysis procedure Perhaps more importantly, the

strategy must be implemented before its environmental

effectiveness can be determined The Jack of strategy testing capability and the need to experiment through implementation can be fairly costly and time consuming shortcomings indeed

A more advanced scheme for the formulation of pollution

management strategies is illustrated in Figure 7.3-3 In this, source inventory techniques are employed to provide input into appropriate air or water quality models, and mon-

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7-8 Approaches for Consideration in Formulating Environmental Controt Strategies

the latter These models can be applied then to provide a clearer picture of the current quality of the environment and to detect possible violations of the accepted set of quality criteria or standards If violations are detected, control approaches can be drawn up and their effectiveness in improving the situation can be conveniently tested through the already calibrated air or water quality models Control approaches drawn and tested this way can be modified

as many times as necessary until a suitable one is found that meets the set environmental, cost and erganizational

requirements and constraints in the most rational way

Existing Situation

Source Inventory | Monitoring/

Calibration

Air/Water Quality Models _

Quality Standards Strategy

No

Control Approaches

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The major advantage offered by the above scheme is its ability to test a control strategy prior to implementation and

to keep testing and improving it in successive iterative steps until a satisfactory level is reached This way, the

need for experimentation through implementation is

eliminated to a large extent, with significant cost and time

savings These advantages however can only be achieved through intensive analysis, and the latter must be assisted

by appropriate and practical tools if the entire exercise is

to be carried out in a comprehensive and time-effective way Selected air and water quality models are provided in

Sections 8.2 and 9.2, while their use in the strategy formulation process is elaborated in Sections 8.1 and 9.1

Implementation of the formulated strategy: This is the sixth major task

in the systems analysis procedure As a general rule, measures se-

Jected through the strategy need further analysis and verification

prior to implementation The statistical validity of the

assessments should always be kept in mind through the use of waste load factors as should significant deviations from predictions for single sources

The extent of such follow-up analysis obviously depends on the

cost of implementation and on the degree of uncertainty we feel in our estimates For example, if the lowering of the sulfur content

of the distillate fuel oil in shown to be necessary for abating

the high S02 levels in an urban study area, the measure can be

promulgated with limited follow-up analysis as the SO emission estimates are generally considered accurate (related

stoichiometrically to the sulfur content of the fuel) If on the

other hand an expensive control system is to be installed, or if a major modification in the height of a large stack is to be made,

additional in-depth analysis is advisable

In addition to follow-up analysis and verification, an implementa-

tion study may be required for some complex measures prior to their execution For example, if LPG is to be used’ for Taxis and other Light Duty Passenger Cars, key implementation aspects must be resolved prior to execution Indeed, the safety of the existing infrastructure (LPG stations, trucks, truck routing etc) must be examined, and regulations for stations, trucks and the conversion of vehicles must be established (Economopoulos, 1987) In another example, if Inspection and Maintenance programmes are to be implemented for external or internal combustion sources, both a feasibility and an implementation study are advisable prior to execu-

tion, Economopoulos (1987, 1991)

The specificity and the relatively small number of measures in the action programmes, using this approach are two important factors that favour implementation Indeed:

Derived strategies comprise, as We have seen, specific tech-

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for reasons explained earlier on in this section, significantly facilitates implementation

The individual measures, which are included in the strategy, are selected, as we have seen, through prioritization The jatter places a clear emphasis for controls in the largest of the sources Indeed, controls on Targe sources are more cost-effective, more reliable, and more easily verifiable because of economies of scale, as well as the availability of improved technical expertise and organization As Figure 7.3-4 shows, the number and the overall complexity of the promulgated measures is an important parameter for the successful implementation of any strategy Ambitious strategies with numerous measures do not necessarily achieve

better end results as the available enforcement

infrastructure is overwhelmed and looses control Experience

shows, many times over, that this is a particularly critical

aspect, and that the results achieved through any strategy are, to a very large degree, controlled in practice by this criterion

OPTIMUM COMPLEXITY OF MEASURES

100 1 = LEGEND 90 — THEORETICAL GAIN ao — IMPLEMENTATION —— REAL GAIN ro 8 8o j 60 40 ao xo 10 b) oO _ COMPLEXITY OF MEASURES

Figure 7.3-4 Optimum complexity of measures as function of the existing infrastructure

Assessment of the end results: This is the seventh and final major task

in the systems analysis procedure and includes the possible ad-

justment of the initial strategy It should be kept in mind in this regard that the process of making assessments of environmen-

tal pollution and devising control strategies is not a single effort, but rather an ongoing process, which builds up from the

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As a concluding remark it should be said that the management of pollu-

tion has been practiced as an art for centuries, but only recently, and to a surprisingly limited degree, as a science Integrated environmental plans designed to maximize cost effectiveness are practically non- existent at national levels, and undoubtedly scarce at study-area level

Yet, experience shows that the potential benefit of such planning is

significant, especially in developing nations, in terms of environmental-, economic-, and time-effectiveness

A rigourous systems approach to environmental management is however a demanding undertaking as it involves, in general, detailed source inventories, a series of sectoral technoeconomic studies analysing the

available control options for all major pollution contributors,

application of environmental quality models, sensitivity analysis and

formulation of optimum strategies in relation to the goals set

(Fconomopoulos, 1987) The above requirements, despite the potential benefits, render the implementation of rigourous systems analysis pro- hibitive in most practical situations Decisions however, to protect the environment have to be made, and systems approach techniques with relaxed analysis requirements, which are easier to implement and which can improve the effectiveness of the promulgated measures, are obviously of practical importance The management approach followed in this book and outtined above combines these advantages

7.4 Bibliography

Economopoulos, A.P., (1987) Development of the Five-Year Air Pollu-

tion Abatement Plan for the Greater Athens Area JAPCA, 37 (8), 889-

97

Economopoulos, A.P., (1991) State of the Art Techniques for Effec- tive Environmental Management 3rd International Symposium on Indus-

try and Environment in the Developing World, High Institute of Pub-

Tic Health/USEPA, Alexandria, Egypt (May 27-29)

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CHAPTER 8 MANAGEMENT OF AIR POLLUTION

8.1 Air Pollution Management Approaches 8.1.1 Outline of Existing Models 8.1.2 Analysis of Air Quality Problems

8.1.2.1 Decoupling of the Air Quality Problem

8.1.2.2 Analysis of Problems Related to Non Reactive Pollutants 8.1.2.2.1 Problems from Point Sources within Urban Areas 8.1.2.2,2Problems from Area Sources within Urban Areas 8.1.2.2.3Problems from Point Sources in Rural Areas 8.1.2.3 Analysis of Problems Related to Photochemical Pollutants 8.1.3 Analysis of Available Control! Options

8.1.3.1 Reduction of Emission Loads at the Source

8.1.3.1.1 Inspection and Maintenance Programmes 8.1.3.1.2Fuel Type and Quantity

8.1.3.1.3S0urce Modification

8.1.3.2 Reduction of Emission Loads Through Controls 8.1.3.2.1 Control Systems for Road Vehicles 8.1.3.2.2 Control Systems for Industrial Sources Reduction of the Emissions impact on Air Quality 8.1.3.3

8.1.3.4 Institutional Measures

8.1.3.4.1 Management of the Vehicle Kilometers Travelled 8.1.3.4.2 Relocation of Industrial Sources

8.1.3.4.3 Temporal Distribution of Area & Point Source Emissions

8.1.3.4.4Management of the Population and Traffic Densities esis of Rational Pollution Control Strategies

Short Term Air Pollution Problems

Annual or Seasonal Air Pollution Problems from Non Reactive Pollutants

Photochemical Air Pollution Problems Management of the Air Pollution Episodes

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8.2 Air Quality Models

8.2.1 Short Term Critical Impact Analysis

8.2.1.1 Impact of Point Sources on the Critical Receptor 8.2.1.1.1 Introduction

8.2.1.1.2Description of the Model 8.2.1.1 3 Example

8.2.1.2 Impact of Point Sources on Any Given Receptor 8.2.1.2.1 Introduction

8.2.1.2.2Description of the Model 8.2.1.2.3Example

8.2.2 Long Term (Seasonal or Annual) Impact Analysis 8.2.2.1 Calculation of the Meteorological Parameters

8.2.2.1.1 Introduction

8.2.2.1.2 The Meteorological Parameters 8.2.2.1.3Example

8.2.2.2 A Model for Point Sources in Urban Setting 8.2.2.2.,1Introduetion

8.2.2.2.2 Description of the Model 8.2.2.2.3Example

8.2.2.3 A Model for the Dispersion of Traffic and Space Heating Emis- sions in Urban Setting

8.2.2.3.1 Introduction

8.2.2.3.2 Description of the Model 8.2.2.3.3Example

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Management of Air Pollution 8-3

8.1 Air Pollution Management Approaches

8.1.1 Outline of Existing Models

The analysis of existing air pollution problems and the formulation of control strategies through the systems approach described in Section 7.3 is facilitated in practice by the use of appropriate tools In this baok a number of such tools are offered:

The source inventory model given in Section 3.2.2 introduces the impact

of all major parameters into the assessment of the air emissions releases, and defines the data requirements from field surveys

This model is thus a valuable tool in air poltution inventory

studies, not only for computing the emission loads, but also for providing guidance on the data to be collected during the field survey work, and for organizing and presenting such data in a con- cise manner (see also Sections 3.2.3 and 3.2.4) The above constitute key elements in the analysis of the existing air pollution

problems

In addition, the model of Section 3.2.2 provides a fairly comprehensive list of the alternative controls for each activity and each source therein, listing both the applicable process alternatives, as well as the established control technologies Further-

more, parameters that exert a particular influence on the emissions are identified and the impact of relevant changes can be quantified (e.g the impact from possible changes in the types and qualities of the fuel used can be easily quantified) The above

provide valuable guidance on the formulation of valid strategies for any given urban or industrial area, and make possible the

quantification of the ensuing air pollution load reductions

The Light Duty Gasoline Powered (LDGP) Vehicle emissions model given in

Section 3.3 supplements the main emission inventory and control model of Section 3.2.2, enabling the user to custom-fit the emission factors to the local and seasonal ambient conditions and driving patterns As both the exhaust and: the evaporative emissions from LDGP Vehicles are variable, the models presented in Section 3.3 deal with both of them The emphasis given on the LDGP vehicle emissions is justified by their particular importance to urban air pollution problems, especially during the ozone peak season, as well as by their significant local and seasonal variability

The flue gas volume model presented in Section 3.4, allows convenient assessment of the actual gas volume’ from external combustion sources as a function of the easily measured (or assumed) CQ concentrations The exit gas volume, along with other information (exit gas temperature, physical stack height, and internal stack diameter) and emission load data, are required for estimating the ambient concentrations from point sources through the application of dispersion models (see Section 8.2.1) As the majority of point

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sources, for which air quality models are applied are industrial or utility boilers, the model presented in Section 3.4 should cover a significant part of the gas volume data requirements

The stack temperature drop model presented in Section 3.5 allows conve-

nient computation of the stack-gas exit temperature, as a function

of the stack-gas inlet temperature and other variables (physical

stack height and diameter, and flue gas volume) It should be noted that although the flue gas exit temperature is a key vari-

able in air quality models, only the stack gas inlet temperature

is usually known from literature and/or from direct measurements The model given in Section 3.5 holds for both insulated and non- insulated stacks and addresses the above input requirements of the air quality models by properly interfacing the raw data which are normally available from field surveys

Selected dispersion models, short term ones for point sources, and long term ones for point and area sources, are given in Sections 8.2.1 and 8.2.2 These models, despite their notable ease of use, offer prediction accuracies that rival these of sophisticated Gaussian dispersion computer models Moreover, the inputs to these models are streamlined and compatible with the outputs from the inventory models presented in Chapter 3 and introduced above

As mentioned in Section 7.3, the basic function of such dispersion models is to translate the emission loads, as predicted from the source inventory models under current or strategy conditions, into ambient air concentrations The latter constitute the criteria of effectiveness of any strategy, as they can be compared with the WHO air quality guidelines listed in Tables I.1-1 and I.1-2, or with the applicable national air quality standards The observa-

tion of such guidelines or standards constitutes, as we have seen, the typical objective of air pollution management studies

In relation to the compatibility of the predictions from the above

model with the guideline values listed in Appendix I, the following are noted:

(a) The point and the area source models used in this book are able to predict concentrations averaged over periods of one

hour, a season or a year, Their output can thus be directly

compatible only with the WHO guidelines or local standards, which are expressed as one hour average, seasonal mean, or annual mean concentrations

There are however, a number of WHO guidelines and local standards, which are based on different averaging periods, e.g 15 mins, 30 mins, 3 hours, 8 hours, or 24 hours (see Tables 1.1-1 and I.1-2) In such cases Equation 8.1.1-1 below can be

used to convert the above guidelines or standards into

Trang 25

ty [p.185

We = Wi — | ( 8.1.1-1 )

In the above Equation, w, and t, are the limiting value, in

ug/m, and the averaging period, in min, of the applicable guideline or standard, while wy, is the computed equivalent "normalized" standard, in pg/mẺ, for an averaging period of

t,=60 min

Equation (8.1.1-1) is applied most appropriately for guide- Jines or standards expressed over averaging periods, t,, from a few minutes to a couple of hours Guidelines with averaging

periods of up to 24 hours could be "normalized", but with a

fair degree of uncertainty An example of the application of Equation (8.1.1-1} is given in Section 8.2.1.2.3

The computed "equivalent normalized" guideline value or standard w, is compatible with our model predictions and can be

used instead of w, in our analysis, as the inherent assump-

tion made is that if y, is observed, then w, will be also ob-

served,

(b) The carcinogenic risk estimates in Table I.1-3 could be used for providing limiting spatial-averaged (over the entire

urban area) or centre-maximum annual mean concentrations, which are compatible with the output of the area source

dispersion model described in Section 8.2.2.3.2 To do this,

a lifetime risk level, acceptable to the local society, should be defined

(c) The concentration of nitrogen dioxide (NO,) and Ozone (05),

can only be predicted through the used of appropriate photochemical models Simple photochemical models do not exist, and for this reason they have not been included in this book

If photochemical pollution is a problem in the study area, _the inventory models provided in Chapter 3 of this book can

be used for generating the necessary data, which can then be inserted into an appropriate photochemical computer model for further analysis

8.1.2 Analysis of Air Quality Problems

The objective of this Section is to describe the use of the air quality

models shown in Section 8.2 for air pollution management purposes

Through the use of these models, sources that cause violations of the applicable air quality guidelines or standards can be identified and the - severity of such violations can be assessed Moreover, the effectiveness

of pollution control measures’ can be assessed and the necessary

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8-G Approaches for Consideration in Formulating Environmental Control Strategies

conditions for meeting the applicable air quality guidelines or stan-

dards can be established

8.1.2.1 Decoupling of the Air Quality Problem

The air quality guidelines or standards can generally be divided into two classes One class aims at protecting human health from acute air pollution effects, and the relevant guideline values or standards refer

to short averaging periods, which span from a few minutes up to 24

hours The other class aims at protecting human health from long term effects and the relevant guideline values or standards refer to annual and/or seasonal average concentrations Practical experience shows that the point and area sources exhibit distinctly different behaviour as far as the violation of each of the above classes is concerned Indeed: Observance of the short term guidelines or standards dictates to a large

extent the allowable emission rates and release conditions from point sources In other words, if point sources are made to operate without violating any short term air quality standards, their long term impact on any receptor will normally be near-negligible Observance of the long term guidelines or standards dictates to a large

extent the control measures in relation to area sources In other words if area sources are made to operate without violating Tong term (seasonal or annual) guidelines or standards, their short

term jmpact will be well within the relevant guidelines or stan-

ards

The practical ramifications from the above observations are significant, for they allow the effective decoupling of the fairly complex overall

aiy quality problem into a number of simpler problems, each of which can be tackled separately In other words, separate analysis can be carried

out for each point source, or for each group of adjacent point sources, as well as for each type of area sources For the former task, point source models are given in Section 8.2.1, and for the latter task, an area source model is given in Section 8.2.2.3

Based on the above, the dispersion models given in Section 8.2 can be used effectively for the identification of existing violations of the applicable air quality guidelines or standards, as well as for assessing the effectiveness of any desirable control strategy More specifically:

The short term models provided in Section 8.2.1 can be used for predict-

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Management of Air Pollution 8-7 against all credible combinations of wind speed, stability class and mixing height, as well as against all receptor distances in cases where the latter is not fixed by the user

The Jong term model for the dispersion of area sources, which is given in Section 8.2.2.3, can be used for assessing the annual or seasonal spatial-average and centre-maximum concentrations over urban areas Separate assessments can be made for each type of source, and from these, the compounded impact from all sources can easily be computed The analysis can be carried out for both the current situation, as well as for any strategy scenario situation The decoupling of the complex overall air pollution problem into a number of simpler problems, each of which can be tackled separately from the rest, leaves unaccounted the possible compounding of pollution lev-

els on any given receptor, from multiple point sources, as well as from

point and area sources While such compounding generally occurs, the following conditions are believed to reduce the severity of this problem for the type of analysis carried out in our studies:

The critical receptor distance for most industrial point sources js of the order of a few hundred meters and only in few cases (e.g large power plants with stack heights of over 200 m) the critical receptor distance is of the order of 1 km Thus, unless major sources operate within a relatively close distance to each other, the compounding effect is weakened Moreover, the relatively low probability of winds coming from, or going towards, another nearby stack, has to be combined with the generally low probability of occurrence of the critical meteorological conditions for the stack under consideration (combination of the critical wind speed, critical stability class and critical mixing height) to produce situations, where the computed critical concentrations could be significantly exceeded due to impact from other upwind or downwind stacks The joint probability for the latter situation to occur tends thus to be small

The usual spatial distribution patterns for point and area sources in urban areas, indicate that area sources (mainly traffic and

space heating) have by far the highest densities in central areas,

where their concentration impact is also the highest Moreover, in urban areas industrial sources with significant emissions are rarely located near the city centre Thus, the locations where the area ane the point sources yield their peak concentrations do not coincide

It is always under unstable conditions that elevated sources produce critical conditions (stability classes A to C), Tables 8.2.1.1.2-1 and 8.2.1.1.2-2 On the contrary, by far the Tlargest

contribution from area sources is during stable conditions (D to F), Figures 8.2.2.3.2-1 and the example in Section 8.2.2.3.3 Thus

the meteorological conditions under which the area and point sources yield their maximum concentrations never coincide

The above differences in both the location and the meteorological conditions under which the maximum impacts of the point and area

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sources are exerted, make the interaction between them rather in- significant for the kind of criticality analysis performed in the

context of this book In other words, the impact of the point

sources on the annual or seasonal average concentrations at the city centre (critical location for the long-term guidelines or

standards) is small, and the same applies for the short term im-

pact of area sources on the computed critical hourly concentrations from point sources

Summarizing the above, the use of the short and long term models given

in Section 8.2 for the identification of the current air pollution prob-

lems and for the formulation of mitigation options offers significant practical advantages, but it has the following shortcomings, which the user should be aware of:

In the analysis of the existing situation most of the sources that are

likely to cause violations of the air quality guidelines or stan-

dards, especially the severe ones, can be expected to be revealed

The existence however, of some additional mild violations, or of violations which are somewhat more intense than these predicted, cannot be excluded, due to the unaccounted compounding of pollution levels from multiple sources

In the formulation of mitigation options, all identified violations of the air quality guidelines or standards can be effectively addressed on an individual basis However, some violations, probably

mitd, may still remain due to the unaccounted compounding of pol-

lution levels from multiple sources Based on the above, the derived mitigations options constitute necessary, but not necessarily sufficient conditions for the eradication of all possible violations

In reality the above limitations are not considered very restrictive, except in unusual cases (e.g in cases where industries with major emissions operate near the city centre, or in industrial zones within urban areas, where many plants with major emissions operate in close distance from each other) Thus, the application of the models provided in Sec- tion 8.2 should be considered sufficient for most study purposes It should be kept in mind however, that after the analysis of the current situation is completed and the desirable air poliution control strategy formulated, the use of an integrated computer model with site-specific meteorological data is strongly recommended so as to obtain a more com-

plete picture (e.g significance of the compounding effects, frequency

of violations) and to justify more fully the need for implementing certain costly measures

Naturally, the above discussion is valid for the dispersion of rela-

tively stable pollutants, as this is a prerequisite for the validity of

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Management of Air Pollution 8-9 8.1.2.2 Analysis of Problems Related to Non Reactive Pollutants

8.1.2.2.1 Problems from Point Sources within Urban Areas

The normal criterion, used in the assessment of stack impact, is the

maximum credible one-hour-average concentration on the critical re-

ceptor The critical impact analysis models provided in Section 8.2.1.1 simplify significantly the relevant analysis procedure For the application of these models the necessary input data requirements are listed

below:

The typical maximum hourly pollutant emission rates, The physical stack height,

The internal stack diameter at the exit level, Whether or not the stack is insulated,

The temperature of the gas at the stack exit level, The actual exit gas volume rate

The typical maximum hourly pollutant emission rates can be computed through the emission load model of Section 3.2, but typical maximum hourly activity data are required for this purpose The latter

cannot be deducted directly from the annual activity data, which are normally collected for our annual source inventory calculations (see Section 3.2.3 and 3.2.4), as the activity cannot be assumed to have a constant rate throughout the year Additional information about typical daily activity rates and hourly distribution profiles would normally have to be collected

Information about the physical stack height, the stack diameter and the stack insulation can be collected during each source survey visit

Data about the gas volume can in principle be obtained during each

source survey visit However, reliable information may not always be available, even for major sources, especially in cases where control equipment is not used In such cases one may use informa-

tion collected from other similar sources, and/or search litera-

ture for relevant information If the source under consideration is an external combustion furnace, the model provided in Section 3.3 can be used for estimating the gas volume as a function of the fuel type and consumption In the latter case accurate estimates can be made if the CQ9 concentration in the flue gas can be measured Finally, the gas volume at its reference temperature wil}

have to be converted into the corresponding volume at the stack

exit temperature through the ideal gas law (see example in Section

3.4.3)

The gas temperature is normally available, or can be easily measured, at the source exit level It can thus be collected through the source

survey visits From this temperature, and from the stack size and

the gas volume information, the gas temperature at the exit stack level can be easily computed through the model provide in Section 3.4

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An example of the application of the above critical analysis procedure

for assessing the maximum credible one hour average ground concentration is given in Table 8.1.2.2.1-1 below Table 8.1.2.2.1-2 summarizes the results of this analysis for all industrial boilers in a study area firing residue fuel oi] Boilers burning low sulfur gaseous fuels and

distillate fuel oi] were excluded from the critical impact analysis as

they were not expected to cause violations of the applicable S0; guideline The computed maximum one-hour average SQ, concentrations can

be compared directly with the WHO guideline value of 350 ug/m?, and, as

it can be seen, several violations could be expected to occur For these cases the minimum stack heights required so as to have the WHO guidelines observed have been computed and their values are also listed in Table 8.1.2.2.1-2 A point to be made in relation to the data listed in Tables 8.1.2.2.1-1 and 8.1.2.2.1-2 is that computer printouts tend to list the computed numbers without much rounding, thereby increasing the accuracy Thus for example, the listed maximum one-hour SO concentration of 1185 ug/m? is accurate within + 20 % at best, and coul have been rounded to 1,200 pg/m

An alternative criterion, which may occasionally be used, is the impact on a user-defined receptor This criterion could be used in cases for example where sensitive receptors, such as hospitals or unique ancient monuments, must be protected through the application of more stringent standards Depending on whether the applicable standards are short or Jong term, the short term impact analysis models of Section 8.2.1.2 or the long term point source model of Section 8.2.2.2 respectively can also be used Naturally, there are other situations where the above models can be used For example, if one wishes to assess the long term impact (seasonal or annual mean concentration) of selected point sources

in the city centre (so as to be considered along with the long term

impact of the area sources), the model 8.2.2.2 can be used

The data requirements of the short term impact analysis models in Sec- tion 8.2.1.2 are the same as these of the models in Section 8.2.1.1,

which were described above The exception is the distance from the

receptor, which this time is an additional model input (for the models in Section 8.2.1.1 the critical receptor distance was a model output) The Jong term point source model 8.2.2.2 has somewhat different input data requirements from the models in Section 8.2.1.2 One or more sets of the meteorological parameters mgq(k) (see Section 8.2.2.1) must be provided, while annual activity data instead of the maximum hourly activity data are used The latter relaxes somewhat the data requirements as the annual activity data are collected for the annual source inventory ralculations and are directly available (see Section 3.2.3 and

.2.4)

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Management of Air Pollution 8-11 Table 8.1,2.2.1-1 Example critical impact analysis for an industrial

boiler (Plant # 18 in Table 8.1.2.2.1-2)

Data Collected: (Plant Survey Visit)

FUEL CONSUMPTION (MAX) : 2077.6 kg/hr SULFUR CONTENT IN FUEL : 3.5 weight % STACK PHYSICAL HEIGHT : 20.0 m

INTERNAL DIAMETER : 1.5m THERMAL INSULATION : NO

CO, IN FLUE GAS (DRY BASIS) : 11.0 Volume %

FLUE GAS TEMP AT BOILER EXIT : 240.0 %

AMBIENT TEMPERATURE : 20.0 %C

AREA TYPE (URBAN/RURAL) : URBAN

Set Objective: (Table I.1-1)

MEET WHO GUIDELINE F0R §0; : 350 ug/n 502

Calculation Procedure:

Max S02 Emission Rate (Section 3.2.2) 50, EMISSION FACTOR : 70,000 kg/MT Fuel

50, EMISSION RATE (MAX): 145.434 kg/h

Flue Gas Volume (Section 3.4.2)

FLUE GAS RATE : 16.376 Am3/s at 200°C

Temp Drop Through Stack (Section 3.5.2)

TEMP DROP THROUGH STACK: 2,7 ĐC

EXIT STACK TEMPERATURE : 237.3 °C

Exit Gas Volume (Ideal Gas Law)

EXIT GAS VOLUME : 16.29 Am3/s

Max Allowable Normalized Critical Conc (Equ 8.2.1.1.2-5 & 6)

ALLOWABLE Coy 2406.6 po/m3/t/h

Critical Stack Impact (Section 8.2.1.1)

PLUME RISE MECHANISM : THERMAL CRITICAL STABILITY CLASS (A to F): C WIND SPEED m/s: 9.2 RECEPTOR DISTANCE m: 82.1

CONCENTRATION, g/m?/t/h: 8145.5

MAX POLLUTANT CONCENTRATION, ug/m3: 1184.6

Alternative Mitigation Options (Section 8.2.1.1)

MINIMUM STACK HEIGHT, im: 40

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Table §.2.2,2.1-2 Example summary of critical stack impact analysis results

8-12 Approaches for Consideration in Formulating Environmental Contre! Strategies

(Page 1 of 2) f= BOILER BOILER BOILER BOILER BOILER BOILER BOILER BOILER BOILER BOILER BOILER BOILER BOILER BOILER BOILER BOILER BOTLER BOILER BOILER BOILER BOTLER BOILER BOILER BOILER BOILER BOILER BOILER BOILER BOILER BOILER BOILER BOILER BOILER BOTLER BOTLER BOILER BOILER BOILER BOTLER of of of of of of of of of of of of of of of of of of of of of of of of of of of of of of of of of BOILERS of Analysis of Boiler # Analysis of Boiler # of of of of of of PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT PLANT ee ee es Be Sk Sổ Sạ # # Sh OAR SR SRR 4 5 8 9 10 11 12 13 15 16 17 18 18 20 22 23 ¿4 25 26 27 28 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 46 47 48 49 |

Max 1hr-Ave Min Stack Stack Height 502 Stack Exit Stack Exit $0 Concent Height m kg/h max An /s deg ug/m> m

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Table 8.1.2,2,1-2 Continued (Page 2 of 2)

"

Max Ihr-Ave Min Stack

Stack Height $02 Stack Exit Stack Exit $09 Concent Height m ka/h max An? /s deg C g/m m

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8.1.2.2.2 Problems from Area Sources within Urban Areas

The normal criteria, fer assessing the impact of the area sources is the long term (annual or seasonal) city-centre maximum concentration, but, occasionally, the long term spatial-average concentration may also be used, The former is directly compatible with long term guidelines on standards, such as those listed in Tables I.1-1 and 1.1-2 Tables I.1-3

and 1.1-4 could also yield compatible limiting values if the maximum

lifetime risk for an individual, which is acceptable by the society, is

defined The latter better characterizes the exposure of the entire

urban population and can be compatible with relevant guidelines or standards Tables I.1-3 and I.1-4 could for example yield compatible

limiting values, if the average lifetime risk, which is acceptable by the society, for the urban population is defined

The area source model given in Section 8.2.2.3, allows convenient compu-

tation of both the long term city-centre maximum and spatial-average concentrations for each type of area source separately, as well as the

compounded total from all area sources The required data inputs include the set of meteorological parameters »(k) (see Section 8.2.2.1), the

effective diameter of the city, the annual or seasonal mean emission density, and the ratio of the city centre over the spatial average emission densities

The effective radius of the city (radius of an ideal circular city with

area equal to that of our study area) can be computed from the

following Equation:

R = (A/n)-5, (8.1.2.2.2-1)

where R is the effective radius in km and A is the actual area of

the city in km2

The mean emission density Qmean for each type of source (e.g space heating furnaces or Light Duty Diesel Powered cars) and for each

pollutant can be computed by dividing the total annual or seasonal

emission loads (as computed through the source inventory procedure, see Section 2.3) by the known area of the city Qmean 78

normally expressed in t/km2-y

The ratio of the centre maximum over the spatial average emission densi-

ties, P=Qnax/Gmean> characterizes the emission density profile

over the city The raw data, which are normally available for the

emission inventory (e.g the total distillate fuel of] consumption for space heating furnaces, or the annual average milage for a

particular type of vehicle) normally refer to the entire study area allowing one to compute Qnean Rarely however, can separate sets of such data be found for the city centre Therefore, for the

assessment of Qmax additional information is required

Two approaches are generally available for the assessment of P

One is based on the calculation of Qmax by collecting the raw

Trang 35

area, annual fuel consumption data for the space heating furnaces

can be collected on a building-by-building basis) The second ap-

proach is based on a direct assessment of P through the use of appropriate indicators For example, it may be assumed in certain

situations that the density of emissions from space heating is proportional to the density of the population or to the building volume The factor P can then be estimated directly as the ratio

of the known city centre to spatial average population or building

volume densities

The area source model given in Section 8.2.2.3 is usually applied for the calculation of the annual average concentrations and for this pur-

pose the annual emission rates and meteorological data are used as inputs In certain cases however, seasonal concentrations may have to be estimated instead For the latter purpose the meteorological data, upon

which computation of the parameters @(k) are based, as well as the emission density, Qmean» and the ratio P=Qnay/Qmean, must be representative of the season under consideration it is interesting to

note in this regard that the "season" need not be a continuous time period, such as the winter months It can also be the morning shift of all working days, or hour 06 of each day of the year This way, the model of Section 8.2.2.3 becomes an extremely potent tool for analysing the impact of temporal distribution of emissions on air quality

8.1.2.2.3 Problems from Point Sources in Rural Areas

The normal criterion, for assessing stack impact, is the critical, one hour average concentration on sensitive user-defined receptors Typical receptors of this sort are the closest residential areas, hospitals etc, over which guidelines or standards for the protection of human health, such as those in Table I.1-1, must be observed The critical, one hour average concentration on the critical receptor might also be used in certain cases as a screening criterion in relation to the health of workers or to the protection of terrestrial vegetation (see Table I.1- 5)

The appropriate point source models for the analysis are those given in

Sections 8.2.1.1 and 8.2.1.2 The entire data collection and analysis procedure is identical to that described in Section 8.1.2.2.1, except that, the urban rather than the rural part of the models must be used 8.1.2.3 Analysis of Problems Related to Photochemical Pollutants The level of the photochemical pollutants (mainly NQ» and 03) is generally more difficult to predict through the use of photochemical models than that of non reactive pollutants through the use of Gaussian dispersion models

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8-16 Approaches tor Consideration in Formulating Environmental Control Strategies

Because of the uncertainties involved, a typical procedure is to measure the hourly NOg and 03 levels through the monitoring network and apply an appropriate photochemical model during selected episodic events so as to

have its predictions verified The verified model can then be used to

predict the required reduction in the VOC emissions, which would be necessary to prevent violation of the relevant guidelines or standards As each VOC reduction prediction applies to a specific episodic event, a number of such events must normally be simulated so as to obtain a more valid overall picture

Simple photochemical models do not exist, and for this reason they have not been included in this book The emissions load models however, provided in Section 3.2 and 3.3, are valuable for the preparation of the necessary inventory inputs to the photochemical models, in cases where the use of the latter appears necessary

8.1.3 Analysis of Available Control Options

8.1.3.1 Reduction of Emission Loads at the Source

The present category comprises measures, which rely on the reduction of

the generated Toads at the source, rather than on their contro] after-

wards Some of the measures in this category have significant impact, are highly cost effective, and easy to implement Thus, some of the highest priority measures in rational air pollution control strategies are likely to belong in this category Reduction at the source represents a promising approach for air pollution control

8.1.3.1.1 Inspection and Maintenance Programmes

Proper inspection and maintenance (I/M) programmes are beneficial for

reducing the emissions generated from most types of sources In this

section the discussion will be limited to the I/M programmes for external and internal combustion sources, as they are particularly

effective and exert a significant impact on the quality of air,

especially over urban areas

Industrial boilers firing fuel oi] are common in both urban and rural

areas They emit significant loads of TSP (black smoke), 509, and NO, A number of parameters, which include excess air used, burner and boiler design, preheating of the fuel, as well as age and state of maintenance of the burner and boiler, affect both the fuel consumption and the rate of emissions Proper maintenance and

frequent regulation goes a long way towards reducing fuel

consumption, and at the same time emissions of SO and especially

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Management of Air Pollution 8-17 proportionally to fuel consumption Smoke however, exhibits a far

greater sensitivity and can be reduced by up to 80%

As an example, in the Greater Athens Area, a feasibility study carried out in 1983-1984 showed that the average smoke emission

factor for the residue oil fired boilers was 2.25 kg/tn of fuel consumed and that this could be lowered to 1.1 kg/tn of fuel consumed through proper I/M procedures (Economopoulos, 1987) A more

recent study demonstrated that the above objective was surpassed, as the average 1991 smoke emission factor was 0.86 kg/tn of fuel,

and that a further decrease was possible down to 0.73 kg/tn of

fuel (Economopoulos, 1991) In addition, the measured increase in

the internal boiler efficiencies, resulted in about 7 % lower fuel

consumption and this was translated into a further 7 % decrease in

black smoke emissions and another 7 % decrease in S502 and NOy emissions As black smoke and SQ constituted in 1985 the prime air pollution problem of Athens, the environmental benefits were

considered significant Along with them, the fuel consumption savings resulted in net economic gains to both the industries

involved and the national economy in general

I/M programmes for industrial boilers are easy to implement, and can be quite successful if properly planned for a smooth start A feasibility study can indicate the potential environmental and

economic benefits for the boilers in the study area, can define an inspection programme and the manpower requirements for its implementation, can set acceptable operating ranges and reporting procedures, and can recommend fines for violations A properly

planned programme can be successfully implemented with only a

smal] number (e.q 2 to 5) of properly trained inspectors

Central space heating furnaces are often fired with distillate fuel oi] and can be important contributors to the air pollution problem (mainly black smoke, SOe, and NOx) Indeed, emissions densities

are high in densely populated areas, the effective release height

is lower than that from industrial boilers, and the temporal dis-

tribution is highly irregular with most of the annual emissions

released within the coldest winter months and in some cases the daily emissions released within a few hours of the day

As in the case of the industrial boilers, the emissions and the

fuel consumption are highly dependent on the type and age of the equipment used and on the quality and frequency of the maintenance provided For example, in the Greater Athens Area, a feasibility

study carried out in 1983-1984 showed that the average smoke emis-

sion factor for distillate oil fired boilers was 1.64 kg/tn of fuel and that this could be lowered to 0.46 kg/tn of fuel though proper I/M procedures (Economopoulos, 1987) In addition, the

measured increase in the internal boiler efficiencies, indicated that about 10 % lower fuel consumption was feasible and this would be translated into a further 10 % lowering of the black smoke

emissions and another 10 % lowering of the SOo and NO, emissions

In a study currently underway (Economopoulos, 1992), the situation

appears to have improved since 1985, due to mandatory annual

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8-18 Approaches for Consideration in Formutating Environmental Control Strategies

boiler maintenance requirements However, as the number of boilers in the study area is large, about 250,000, and the inspection inadequate, the 1985 target has not been achieved The latter is at- tributed to infrequent maintenance of the boilers and to the low quality of the maintenance work In relation to the latter, most of the boilers maintained over the current winter season could be readjusted to achieve several percentage points higher internal thermal efficiency and a drastic reduction in smoke emissions Overall statistics are not yet available, but the differences were so significant that the impact of improper maintenance emerged as a factor of prime importance

Based on the above, the 1/M programmes for central heating boilers are important both for environmental and economic reasons, but their implementation is hampered by the large number of boilers in the study area Inadequate inspection was found to result from both infrequent boiler maintenance and from improper quality of maintenance To address the above problems, the following I/M implementation strategy was developed, and is in the process of being implemented within the Municipality of Athens (Fconomopoulos, 1991 & 1992):

Inspection over a large metropolitan area or region is carried out through a Central Computerized Enforcement Unit, which relies on axternal licensed mechanics to regularly inspect and maintain the boilers and to issue the boiler maintenance reports, on a few internal inspectors to check the quality of work of the licenced

mechanics, and on a computer system to keep tight control of the

boiler maintenance progress and of each licensed mechanic’s performance record

More specifically, building superintendents are asked to send by mail the reports produced by the licensed mechanics upon comple- tion of the boiler maintenance, and the received data are entered in the computer for analysis Warning letters are automatically

printed to building superintendents failing to abide, and fines

are issued if no corrective action is taken An inspection

programme is automatically generated aimed at checking the quality of work of, and the accuracy of the information supplied by, each

licensed mechanic

The central points in the philosophy of the above scheme are the following:

1 The building superintendents are responsible only for the

timely maintenance of their boilers and not for the quality of maintenance work performed For the latter the responsibility

rests with the licenced mechanic, who issues the maintenance report

2 The central computerized enforcement unit, needs not enforce the law through periodic inspection of hundreds of thousands

of buildings, but rather to ensure that the quality of work of a Few hundred licenced mechanics is up to acceptable stan-

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8-19

Management of Air Pollution

Road vehicles are responsible for most of the NO,, CO and VOC, as well

as for a fair fraction of the black smoke and S02 emissions in ur-

ban areas As in the case of industrial and space heating boilers, emission loads and fuel consumption are highly dependent on the type and age of the vehicle and on the quality and frequency of the maintenance provided

The effectiveness of I/M programmes depends to a Targe extent on the age of the vehicles and the pollution control technology used As a general rule the older and the more polluting the vehicle, the more effective the I/M programme For example, a feasibility

study carried out in 1983 showed that for the aging fleet of Light Duty Gasoline Powered (LDGP) cars of Athens at that period a strict I/M programme could be expected to reduce CO emissions by

25-40 %, VOC emissions by 15-25 % and gasoline consumption by about 7 % (Economopoulos, 1987) Somewhat lower effectiveness of 1/M programmes can be expected for modern conventional LDGP cars according to a recent study by TNO (1990) Indeed, for the

category of modern conventional (non catalytic) cars the anticipated reduction of CO is about 25 %, of VOC about 15% and of fuel consumption about 3 % It is interesting to note that the

emissions from LDGP cars equipped with 3-way open loop catalyst show the highest sensitivity to proper tuning with the CO and VOC

emissions reduced by 40 % and 35 % respectively while the NO,

increased by about 12 % On the other hand emissions from LDGP

cars equipped with 3-way controlled catalysts were found to be

practically unaffected by maintenance

The implementation of effective 1/M programmes for Diesel Powered vehicles is relatively simple, since visual observation can be used for screening the passing vehicles and for identifying those likely to be untuned (high black smoke emissions are clearly visi- ble), and a short test on the road can be used for testing the

compliance of the latter to relevant regulations Through the

above system, and with only a few mobile inspection teams, it was

possible to achieve effective implementation of I/M programme for

Diesel Powered vehicles in the Greater Athens Area This, along with the I/M programmes for industrial and space heating boilers, contributed to the lowering of the annual mean levels of black

smoke in the city-centre from 185 pg/m? in 1985 to its present

level of about 100 ug/m

Effective I/M programmes for LDGP vehicles are more difficult to implement as the number of vehicles is usually far larger, visual screening on the road is not feasible, short tests have serious limitations, and finally the general public is affected It should be noted in this regard that short tests are more suitable for conventional cars with carburettors and, in any case, can only be used to distinguish gross violations Proper tests on the dy- namometer on the other hand are far too expensive for they involve costly equipment and require time to be completed To get around this problem, the maintenance procedure is based on the periodic checking of all engine components that affect the emissions and

their adjustment according to the car manufacturer recommenda-

tions The implied assumption in this case is that if all compo-

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nents function as specified by the manufacturer, the emissions will be at the manufacturer certified level The above procedure solves, aven though indirectly, the maintenance part of the problem, but leaves unanswered the inspection part of it In view of

the above limitations the following implementation strategy has

been formulated and proposed for the city of Athens (Economopoulos et al, 1992):

1 The owners are responsible only for the periodic maintenance of their vehicles and for not tampering with the emission control systems (removal of catalyst and lambda sensors, if any) Compliance of the owners can easily be established through sporadic on-the-road checks, of valid maintenance certificates and through visual inspection of the physical existence of control systems

2 Maintenance certificates are issued by authorized garages,

which are solely responsible for the quality of their work The latter is verified through a small number of inspection teams, which, on a random basis and without prior notifica- tion, check the tuning of certified cars on the spot, upon their exit from the garage

This way, the inspectors need not measure the emissions from a very large number (e.g several hundred of thousands) of vehicles, but rather can ensure that the quality of work of a very small

number (e.g a few hundred) of authorized garages is satisfactory

Centralized government-operated testing stations provide an alternative approach for emission testing and the issuing of valid maintenance certificates This may be particularly advantageous in situations where periodic testing of the vehicle road safety systems already takes place This approach however is not without disadvantages, as the capacity of the existing facilities, where they exist, may not be sufficient for the periodic inspection of all vehicles, and as the maintenance and adjustment required, especially for older cars, is normally carried out elsewhere, for example in private garages from where the maintenance certificate could be directly issued

Undoubtedly, effective I/M programmes exist for many types of sources and proper implementation strategies that suit local conditions in each particular study area need to be formulated The discussion above was necessarily restricted to only a few types of sources The purpose of describing the above implementation strategies is to illustrate a suitable procedure rather than to define or recommend particular approaches

8.1.3.1.2 Fuel Type and Quantity

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