CHAPTER MANAGEMENT 8.1 OF AIR POLLUTION 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 8.1.2.3 8.1.3 8.1.2.2,2Problems from Area Sources within Urban Areas 8.1.2.2.3Problems from Point Sources in Rural Areas Pollutants Analysis of Problems Related to Photochemical 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 8.1.3.3 8.1.3.4 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 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 Emissions 8.1.3.4.4Management of Area & Point Source of the Population and Traffic Densities esis of Rational Pollution Control Strategies Short Term Air Pollution Problems Annual or Seasonal Pollutants Air Pollution Problems from Photochemical Air Pollution Problems Management of the Air Pollution Episodes Non Reactive 8-2 Approaches for Consideration in Formulating Environmental Control Strategie s 8.2 Air Quality Models 8.2.1 Short Term 8.2.1.1 8.2.1.2 Critical Impact Analysis 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 Example Impact of Point Sources on Any Given 8.2.1.2.1 Introduction 8.2.1.2.2Description of the Model Receptor 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 8.2.2.2 8.2.2.1.3Example A Model for Point Sources in Urban Setting 8.2.2.2.,1Introduetion 8.2.2.3 8.2.2.2.3Example A Model for the Dispersion of Traffic and sions in Urban Setting 8.2.2.2.2 Description of the Model 8.2.2.3.1 Introduction 8.2.2.3.2 Description of the Model 8.2.2.3.3Example 8.3 Bibliography Space Heating Emis- Management of Air Pollution 8.1 Air Pollution 8.1.1 Outline 8-3 Management Approaches 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 model a 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 is thus 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 concise 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 Powered air (LDGP) pollution Vehicle load reductions The Light Duty Gasoline emissions model given in 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 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 8-4 Approaches for Consideration in Formulating Environmental Control Strategies sources, for which air quality or utility boilers, the model cover a significant part of the The stack temperature nient computation stack noted and flue height and diameter, that although the flue gas exit of able the inlet stack-gas in the only models, quality air and temperature as a function (physical variables other conve- allows temperature, exit stack-gas 3.5 in Section presented drop model of the models are applied are industrial presented in Section 3.4 should gas volume data requirements It should be gas volume) temperature is a key vari- inlet gas stack temperature is usually known from literature and/or from direct measurements The model given in Section 3.5 holds for both insulated and noninsulated air quality normally and stacks models available by from properly field input above the addresses the interfacing surveys of requirements raw which data the are 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 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- In relation to the compatibility model with the guideline ing are noted: (a) values of the listed The point and the area source able to predict concentrations hour, a season or a year, Their seen, as we have studies tion of such guidelines or standards constitutes, the typical objective of air pollution management predictions in Appendix from I, the the models used in this book averaged over periods of output can compatible only with the WHO guidelines which are expressed as one hour average, annual mean concentrations or thus be above follow- are one directly local standards, seasonal mean, or There are however, a number of WHO guidelines and local standards, which are based on different averaging periods, e.g 15 mins, 30 mins, hours, 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 equivalent "normalized" model predictions: above ones, guidelines which are or standards compatible with into our Management of Air Pollution ty [p.185 | We = Wi In the above ( 8.1.1-1 ) — Equation, w, 8-5 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 Equation (8.1.1-1) is applied most appropriately for guideJines 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 fair degree of uncertainty Equation (8.1.1-1} is given could be "normalized", but with An example of the application in Section 8.2.1.2.3 a of 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 tion made is that if y, is observed, served, (b) The for urban which annual output area) or centre-maximum are compatible with the model a lifetime risk should be defined The inherent assump- be also ob- carcinogenic risk estimates in Table I.1-3 could be used entire the (over spatial-averaged limiting providing dispersion (c) the then w, will acceptable level, nitrogen of concentration Section in described mean concentrations, of the area source the (NO,) dioxide this, Ozone (05), To 8.2.2.3.2 to local and society, can only be predicted through the used of appropriate photomodels not exist, chemical models Simple photochemical in this book included and for this reason they have not been in the study area, of this book can If photochemical pollution is a problem _the inventory models provided in Chapter be used for generating the necessary data, which can then be inserted into an appropriate photochemical computer model for further analysis Analysis 8.1.2 The objective models shown of this in of Air Section Section Problems Quality 8.2 is to for describe the pollution air use of the management air quality purposes Through the use of these models, sources that cause violations of the applicable air quality guidelines or standards can be identified and theseverity of such violations can be assessed Moreover, the effectiveness of pollution control measures’ can be assessed and the necessary 8-G Approaches for Consideration in Formulating Environmental Control Strategies conditions dards can for meeting be established 8.1.2.1 Decoupling the applicable of the Air air Quality quality guidelines or stan- 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 hours The averaging other periods, class which aims at span protecting from a human few minutes health from up long to 24 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 term term if area (seasonal jmpact sources will or are annual) be well made to operate guidelines within the or without standards, relevant violating their guidelines or Tong short stan- ards The for practical ramifications from the above observations are significant, 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- ing the critical hourly concentration from each stack, or group of neighbouring stacks, which emits within the study area The computed critical concentrations provide a valid yardstick, allowing a decision to be made about whether the stack impact is acceptable oy not, and in the latter case it provides a particularly valuable criterion, to judge the effectives of alternative mitigation options This analysis can be achieved in a simple straightforward manner, without even the need of site-specific meteorological data, as the predicted critical concentrations have been maximized 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 the rest, ber els point of simpler of the leaves on any given and area complex problems, each unaccounted receptor, sources following conditions are for the type of analysis overall of the air which possible from multiple While such believed to carried out pollution can be problem tackled compounding point compounding reduce in our sources, of a num- from pollution lev- as well as from of problem generally the severity studies: into separately occurs, this the 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 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 in urban space spatial distribution patterns for point and areas, indicate that area sources (mainly heating) have by far the highest densities area sources traffic and 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 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 sources yield their conditions under which the area and maximum concentrations never coincide The above differences in both the location conditions under which the maximum impacts point and the meteorological of the point and area 8-8 Approaches for Consideration in Formulating Environmental Control Strategies sources are significant context of sources city exerted, make the interaction between them rather for the kind of criticality analysis performed in inthe the the this on centre standards) is book In annual (critical small, the in Section above, 8.2 the for the seasonal location and the pact of area sources on tions from point sources Summarizing other or the use analysis likely of the to of dards, the the applies the for the and short hourly long point at guidelines the critical short of long-term term of the current situation violations especially for impact concentrations term or im- concentra- models given air pollution prob- mitigation options offers significant the following shortcomings, which the existing cause the average computed identification lems and for the formulation of practical advantages, but it has user should be aware of: In the same words, severe of the air ones, most of the quality can sources guidelines be expected that or are stan- to be revealed The existence however, of some additional mild violations, or of violations which are somewhat more intense than these predicted, cannot tion In the be levels excluded, from due to multiple the unaccounted compounding sources of pollu- 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 the above limitations 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 are not considered very restrictive, except in unusual cases (e.g in cases where industries with major sions operate near the city centre, or in industrial zones within areas, from tion should where each 8.2 be many other) should kept in plants be with Thus, the major considered mind emissions application however, sufficient that of after the for the operate in most study models close provided analysis of emisurban distance in purposes the Sec- It 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 of tain picture violations) costly Naturally, tively (e.g and to measures the stable above significance of discussion is justify pollutants, more as this the fully valid compounding the for need the is a prerequisite for effects, frequency implementing dispersion for the of cer- rela- validity of all models in Section 8.2 Photochemical models, not provided in this book, must be used for predicting NO, and 0, levels (see Section 8.1.3 below) and a somewhat different approach must be followed for the development of relevant control strategies (see Section 8.1.4) Management of Air Pollution 8.1.2.2 Analysis of Problems 8.1.2.2.1 Problems from The normal maximum criterion, credible Related Point used to Non Sources in the Reactive within Urban assessment one-hour-average of Pollutants Areas stack concentration 8-9 on the impact, is 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 The physical stack The internal stack Whether or not the The temperature of The actual exit gas The hourly height, diameter stack is the gas volume pollutant emission at the exit insulated, at the stack rate rates, level, exit level, 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 are tions sumed be deducted normally directly collected from for (see Section 3.2.3 to have a constant our the annual annual source activity data, inventory which calcula- and 3.2.4), as the activity cannot be rate throughout the year Additional formation about typical daily activity rates and hourly tion profiles would normally have to be collected asin- distribu- Information stack about the physical stack height, the stack diameter and the insulation can be collected during each source survey visit Data the about source gas volume survey visit collected from can in principle However, reliable be obtained information during may not each always be available, even for major sources, control equipment is not used In such especially in cases where cases one may use informa- ture source tion is for an relevant external other similar information combustion If furnace, sources, the the and/or model under search litera- consideration 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 have exit to Finally, be temperature 3.4.3) The gas temperature the source the gas survey level 3.4 the converted exit visits can volume be gas volume into through the is normally level From It this can its ideal thus gas be temperature, computed reference corresponding available, information, easily at the the gas through law (see or can be and from collected temperature the model temperature volume at example easily through the at stack in Section measured, stack the provide wil} the the size exit in at source and stack Section 8-10 An Approaches for Consideration in Formulating Environmental Control Strategies example of the application of the above critical analysis the critical impact 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 they were guideline be compared it can be cases the oi] were excluded from analysis not expected to cause violations of the applicable The computed maximum one-hour average SQ, concentrations directly seen, with several minimum guidelines the stack observed WHO guideline violations have could heights been value be required computed and of 350 expected so to as their ug/m?, and, occur to For have values are also the as S0; can as these WHO 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 on alternative a example where monuments, standards Jong sensitive the long short term (seasonal impact of the city source or annual centre (so area were model mean as to sources), The data requirements tion 8.2.1.2 are the which may occasionally criterion impact Naturally, there used For example, impact the This receptors, term point also be used models can be in which receptor must be protected through Depending on whether the term, the criterion, user-defined such as data of Jong term the provided, tivity as tory point the data annual are annual activity analysis of models Section concentration) be considered 8.2.2.2 exception model the of 8.2.2.2 of can is the for ancient 8.2.1.2 respectively used or can the above long term point the has distance input (for was a model somewhat activity data instead of data collected parameters The latter are are mgq(k) relaxes directly it (see Section somewhat for available appears evaluated, need to general procedural analysis be 8.2.1.2 discussion impact impact cases Section with Section Indeed, all large-, as well as normally surveyed and only these ical the in unique selected along in the preceding 8.2.2.2 models and which is to be line with the or is are other situations where if one wishes to assess the The ralculations 2.4) From source from used used the application of more stringent applicable standards are short or the model above meteorological while used, sources long term of the short term impact analysis models in Secsame as these of the models in Section 8.2.1.1, described requirements be hospitals receptor, which this time is an additional model in Section 8.2.1.1 the critical receptor distance The be could that the the the (see all from different One or 8.2.2.1) maximum data annual input more must hourly sets be ac- requirements source Section sources, the the models output) the inven- 3.2.3 impact and of be surveyed This requirement is in aspects discussed in Section 2.3 a number of medium-, size sources are sources are normally subjected to crit- ... summary of critical stack impact analysis results (Page of 2) f= | Stack Height of PLANT of PLANT of PLANT Sk of PLANT of BOILER of of PLANT PLANT PLANT of PLANT of PLANT of PLANT of of of PLANT... Emis- Management of Air Pollution 8.1 Air Pollution 8.1.1 Outline 8-3 Management Approaches of Existing Models The analysis of existing air pollution problems and the formulation of control strategies... 16.4 Management of Air Pollution Table 8.1.2,2,1-2 Continued (Page 8-13 of 2) " Stack Height m BOILERS of PLANT # of Boiler # Analysis of Boiler # BOILER of PLANT # 51 BOILERS of PLANT # 52 of