Advection - Diffusion numerical model of air pollutants emitted from an urban area source with...

7/29/2019 Advection - Diffusion numerical model of air pollutants emitted from an urban area source with removal mechanis

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International Journal of Application or Innovation in Engineering& Management (IJAIEM)Web Site: www.ijaiem.org Email: [email protected], [email protected]

Volume 2, Issue 2, February 2013 ISSN 2319 - 4847

Volume 2, Issue 2, February 2013 Page 251

ABSTRACT

A two-dimensional mathematical model of primary and secondary pollutants of an area source with chemical reaction and dry

deposition by considering point source on the boundary is presented. One of the important atmospheric phenomena is theconversion of air pollutants from gaseous to particulate form. The primary pollutants which are emitted directly to the

atmosphere are converted into secondary pollutants by means of chemical reaction. The governing partial differential equation

of primary and secondary pollutants with variable wind velocity and eddy diffusivity is solved by using Crank-Nicolson implicitfinite difference technique. Consistency, stability and convergence criteria have been tested for the numerical scheme used in

this model. Concentration contours are plotted and the results are analyzed for primary and secondary pollutants in stable and

neutral atmospheric conditions for various meteorological parameters and transformation processes.

Keywords: Primary and secondary pollutants; chemical reaction; variable wind velocity; eddy diffusivity; CrankNicolson implicit scheme.

1.INTRODUCTIONRapid industrialization and urbanization have posed a serious threat to human life and environment in recent years.The toxic gases and small particles could accumulate in large quantities over urban areas, under certain meteorologicalconditions. This is one of the serious health hazards in many of the cities in the world. Over the past three or fourdecades, there have been important advances in the understanding of the actions, exposure-response characteristics, andmechanisms of action of many common air pollutants. A multidisciplinary approach using epidemiology, animaltoxicology, and controlled human exposure studies has contributed to the database. This review will emphasize studiesof humans but will also draw on findings from the other disciplines. Air pollutants have been shown to cause responses

ranging from reversible changes in respiratory symptoms and lung function, changes in airway reactivity andinflammation, structural remodeling of pulmonary airways, and impairment of pulmonary host defenses, to increasedrespiratory morbidity and mortality [1]. Tropospheric ozone is known to be an important pollutant and it has beenestablished that ozone has significant impact on human health globally [2]. The problem of air pollution in cities hasbecome so severe that there is a need for timely information about changes in the pollution level. Today forecasting ofair quality is one of the major topics of air pollution studies due to the health effects caused by these airborne pollutantsin urban areas during pollution episodes [3]. Atmospheric particulate matter (PM) in the micrometer size range followsa bimodal distribution, with a coarse mode including particles produced by mechanical processes, such as soil dust,cloud droplets and many biological particles [4] and a fine mode dominated by both primary anthropogenic pollutionfrom combustion processes and gastoparticle conversion [5]-[7]. The primary pollutants which are emitted directly tothe atmosphere is converted into secondary pollutants by means of chemical reaction. Study of such conversion processin which sulphur dioxide is converted to particulate sulfate, nitrogen oxide to particulate nitrate and hydrocarbons toparticulate organic material would reveal a lot on urban plume characteristics [8]. The study of the secondary pollutants

is important as the life period of the secondary pollutants is longer than that of the primary pollutants and it is morehazardous to human life and environment protection.Several studies have reported in which the downwind measurements of large urban complexes were carried out in orderto obtain material balances on gaseous and particulate pollutants [9]-[12]. Acid precipitation can occur when the

Advection - Diffusion numerical model of

air pollutants emitted from an urban areasource with removal mechanisms by consideringpoint source on the boundary

Lakshminarayanachari K.1, *Sudheer Pai K .L.2, Siddalinga Prasad M.3 and Pandurangappa, C.4

1Department of Mathematics, Sai Vidya Institute of Technology, Bangalore - 560 064, INDIA2Principal, R N S First Grade College, Bangalore - 560 098, INDIA

3Department of Mathematics, Siddaganga Institute of Technology, Tumkur - 572 103, INDIA4Department of Mathematics, Raja Rajeswari College of Engineering, Bangalore - 560 074, INDIA

*corresponding author


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particles and the gases are removed from the atmosphere by (i) rain and snow (wet deposition) (ii) by impaction onwater, soil and vegetation surfaces (dry deposition) and (iii) gravitational settling velocity. The transformation of thegases to the particles in the atmosphere and the deposition rates of the gases and the particles are a function ofmeteorological conditions over a time and the distribution of emission sources. In order to justify controls on theemissions of acid precursors, the relationship between a source and the deposition pattern that it produces needs to be

understood [13]-[14]. The prediction of the concentration of pollutants is difficult to accomplish by field monitoring.Mathematical modeling is the only way to estimate the relative contribution of sources to the total deposition at aparticular receptor over a long period of time.There is an interesting Lagrangian finite difference model, which has been developed using fractional step method by[15]to compute time dependent advection of air pollutants. In this model, the Eulerian grid used for the diffusion partof the pollutant transport equation remains unchanged. The finite difference scheme used avoids the numerical pseudodiffusion and it is unconditionally stable. The numerical solution obtained is compared with the correspondinganalytical solution of steady state case and a reasonable agreement has been found [15]. In this paper he has given abrief discussion of related numerical schemes like puff-in-cell methods by [16] and conservation of momentum modelby [17]. However, the work of [15]does not deal with the secondary pollutant or any kind of removal processes. Lateron, [18] have presented an intermediate range grid model with point source for atmospheric sulpher dioxide andsulphate concentrations. This model deals with the atmospheric transport, diffusion, and wet and dry depositions over aregion of several hundred kilometers. In this long range analytical model, some of the restrictive assumptions likeconstant velocity and eddy diffusivity profiles are imposed. [19] presented a two-dimensional analytical model forturbulent dispersion of pollutants in stable atmospheric layer with a quadratic exchange coefficient and a linear velocityprofile. This model does not take into account any removal mechanisms. A numerical model is developed for thedispersion with chemical reaction and dry deposition from area source, which is steady state in nature [20]. All thesearea source models deal with only primary inert air pollutants. Subsequently, [21] presented a time-dependentnumerical model for both primary and secondary pollutants in order to obtain time dependent contours of pollutantconcentration in urban area. This model has been solved by using the fractional step method taking into account thespecified functional form of vertical eddy diffusivity and velocity ( ) profiles. [22] presented a timedependent area source mathematical model of chemically reactive air pollutants and their byproduct in a protected zoneabove the surface layer with rainout/ washout and settling. But the horizontal homogeneity of pollutants and constanteddy diffusivity are assumed in this model. [23] has presented a time dependent two-dimensional air pollution modelfor both the primary pollutant (time dependent emission) and the secondary pollutant with instantaneous (dry

deposition) and delayed (chemical conversion, rainout/washout and settling) removals. However his model beinganalytical, deals with the uniform velocity and eddy diffusivity profiles. Both [24] and [25] have presented a modelingof the urban heat island in the form of mesoscale wind and of its effect on air pollution dispersal. These numericalmodels deal with only primary inert air pollutants.A numerical model for the primary and the secondary pollutants with more realistic wind velocity and eddy diffusivityprofiles by considering point source on the boundary is proposed in this paper. The effect of removal mechanism i.e,dry deposition velocity on primary and secondary pollutants is analysed. The model has been solved by using Crank-Nicolson implicit finite difference technique. The finite difference scheme used in this model avoids numerical pseudo-diffusion and it is unconditionally stable. Consistency, stability and convergence criteria have been tested for thenumerical scheme used in this model. We have computed concentration residue, obtained after every time step againstthe number of time steps and analyzed. Accuracy depends on the fall in residue. It is seen that the residue settles toaround 10-6. For the grid-independence study we have computed concentration for , ,

and grids and analyzed. The analysis reveals that concentration of the primary and secondary pollutantsfor and grids differ considerably against those on grids. Further, there is no perceptiblechange of values occurring on grids from that of grids. It is therefore reasonable to assume thatthe solution obtained on grids is an independent solution. The above computational cycle is then repeatedfor each of the next time levels. The steady state solution is obtained when the convergence criteria for the residualdefined as

is satisfied. Here, is the concentration which stands for both and , n refers to time, i andj refer to the spacecoordinates.

2.MODEL DEVELOPMENTThe dispersion of chemically reactive pollutant concentration in a turbulent atmospheric medium using K-theoryapproach is usually described by the following equation [26].


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whereC is the pollutant concentration in air at any location (x, y, z) and time t; and are the coefficients of

eddy diffusivity in the x, y and z directions respectively; U, V and W are the wind velocity components in x, y and zdirections respectively and S is the source or sink of the air pollutants.

The physical problem consists of an area source of an urban city with finite downwind and infinite crosswinddimensions with the point source (industrial stack) on the z-axis with and m. The grid points maymiss the source because the source is at an arbitrary point. In this case the grid points have to be taken on the sourcepoint. To overcome this difficulty, one can think of the following two methods. One is to use Gaussian distribution forpollutants source at the initial line which is equivalent to the above point source and the other is distributing the pointsource to its neighboring two grid points. We have used the second procedure in this numerical model for air pollutantsto take into account of a source at an arbitrary point on the z-axis. We have equally distributed the point source to itsneighboring two grid points on z-axis. We assume that the pollutants are emitted at a constant rate from uniformlydistributed area source. The Physical description of the model is shown schematically in Figure 1.

Figure 1. Physical layout of the model

We intend to compute the concentration distribution both in the source region and source free region till the desireddistance =12000 meters in the downwind. We have taken the primary source strength at groundlevel from an area source and the mixing height is selected as 624 meters. We have considered the point sourcestrength as in this model.

2.1Primary pollutant

The governing equation of primary pollutant can be written as

(1)

where is the ambient mean concentration of pollutant species, is the mean wind speed in x-direction,

is the turbulent eddy diffusivity in z-direction and k is the first order chemical reaction rate coefficient of primary

pollutant . Equation (1) is derived under the following assumptions:The lateral flux of pollutants along the crosswind direction is assumed to be small i.e.,

where is the velocity in the y - direction and is the eddy-diffusivity coefficient in the y - direction.

Horizontal advection is greater than the horizontal diffusion for not too small values of wind velocity, i.e.,meteorological conditions are far from stagnation. The horizontal advection by the wind dominates over the horizontal

diffusion, i.e., where and are the horizontal wind velocity and horizontal eddy diffusivity

alongx - direction respectively.

Vertical diffusion is greater than the vertical advection since the vertical advection is usually negligible compared tothe diffusion owing to the small vertical component of the wind velocity.We assume that the region of interest is free from the pollution at the beginning of the emission. Thus, the initialcondition is

(2)Where is the length of desired domain of interest in the wind direction and is the mixing height. We assume thatthere is a point source (industrial stack) on , i.e either at the beginning or at the end of the urban city. The winddirection is assumed towards the city from the point source. Thus


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(3)

where z is taken as height. We assume that the chemically reactive air pollutants are emitted at a constant ratefrom the ground level and they are removed from the atmosphere by ground absorption. Hence the correspondingboundary condition takes the form

(4)

where is the emission rate of primary pollutant species, is the source length in the downwind direction and is

the dry deposition velocity. The pollutants are confined within the mixing height and there is no leakage across the topboundary of the mixing layer. Thus

(5)

The term in equation (1) represents conversion of gaseous pollutants to particulate material as long as the process

can be represented approximately by first-order chemical reaction. Bimolecular, Three-body, Photolysis and ThermalDecomposition are some the chemical reactions which take place in the atmosphere to form secondary pollutants andsecondary aerosols.

1.2 Secondary pollutantThe governing equation for the secondary pollutant is

(6)

where, is the mass ratio of the secondary particulate species to the primary gaseous specieswhich is being converted.

In deriving equation (6) we have made similar assumptions as in the case of primary pollutant.

The appropriate initial and boundary conditions on sC are:

(7)

(8)

Since there is no direct source for secondary pollutants, we have

(9)

(10)

where is the dry deposition velocity of the secondary pollutant .

3.METEOROLOGICAL PARAMETERSThe treatment of equations (1) and (6) mainly depends on the proper estimation of the diffusivity coefficient and thevelocity profile of the wind near the ground/or the lower layers of the atmosphere. The meteorological parametersinfluencing eddy diffusivity and velocity profiles are dependent on the intensity of turbulence, which is influenced byatmospheric stability. Stability near the ground is dependent primarily upon the net heat flux. In terms of the boundarylayer notation, the atmospheric stability is characterized by the parameter L [27], which is also a function of net heatflux among several other meteorological parameters. It is defined by

(11)

where *u is the friction velocity, the net heat flux, the ambient air density, the specific heat at constant

pressure, the ambient temperature near the surface, the gravitational acceleration and the Karmans constant 0.4. and consequently represents stable atmosphere, and represent unstable

atmosphere and and represent neutral condition of the atmosphere.

The friction velocity is defined in terms of geostrophic drag coefficient and geostrophic wind such that


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(12)

where is a function of the surface Rossby number , where is the Coriolis parameter due to earths

rotation and is the surface roughness length. [28]Lettau (1959) gave the value of the drag coefficient for a

neutral atmosphere in the form

(13)

The effect of thermal stratification on the drag coefficient [28] can be accounted through the relations:

for unstable flow, (14)

for slightly stable flow and (15)

for stable flow. (16)

In order to evaluate the drag coefficient, the surface roughness length z0 may be computed according to the relationship

developed by [29] i.e., , where is the effective height of roughness elements, a is the frontal areaseen by the wind and is the lot area (i.e., the total area of the region divided by the number of elements).Finally, in order to connect the stability length L to the Pasquill stability categories, it is necessary to quantify the net

radiation index. The following values of fH (Table 1) are used for urban area [30].

Table 1. Net heat flux

Net radiating index : 4.0 3.0 2.0 1.0 0.0 -1.0 -2.0

Net heat flux : 0.24 0.18 0.12 0.06 0.0 -0.03 -0.06

3.1 Eddy diffusivity profiles

Following gradient transfer hypothesis and dimensional analysis, the eddy viscosity KM is defined as

(17)

By using [27] similarity theory, the velocity gradient may be written as

(18)

Substituting equation (18) in equation (17), we have

(19)

The function depends on, where is Monin-Obukhov stability length parameter. It is assumed that the surface

layer terminates at for neutral stability. For stable conditions, surface layer extends to

For neutral stabilitywith (within surface layer)

and (20)

For stable flowwith ,

(21)

(22)

For stable flowwith ,

(23)

It has been shown that by [31]. In the PBL (planetary boundary layer), where is greater than the limits

considered above and , we have, the following expressions for

For neutral stabilitywith ,


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(24)

For stable flowwith , up to , the mixing height,

. (25)

Equations (19) to (25) give the eddy viscosity for the conditions needed for the model. However, the model deals withthe transport of mass rather than the transport of momentum, as implied by the use of viscosity. Since both the massand the momentum are transported by turbulent eddies, it is physically reasonable to assume that the turbulent viscositycoefficient is numerically equivalent to the eddy diffusivity coefficient . Also, there is some experimentalevidence that the ratio remains constant and equal to unity, at least in the surface layer as shown by [31]. Thecommon characteristic of is that it has a linear variation near the ground, a constant value at mid mixing depth anda decreasing trend as the top of the mixing layer is approached. An expression based on theoretical analysis of neutralboundary layer [32], in the form

(26)

whereH is the mixing height.

For stable condition, [33] used the following form of eddy-diffusivity,

, (27)

The above form of was derived from a higher order turbulence closure model which was tested with stable boundary

layer data of Kansas and Minnesota experiments.Eddy-diffusivity profiles given by equations (26) and (27) have been used in this model developed for neutral and stableatmospheric conditions.

1.3 Wind velocity profilesIn order to incorporate more realistic form of velocity profile in our model which depends on Coriolis force, surface

friction, geosrtophic wind, stability characterizing parameter L and vertical height z, we integrate equation (13) fromto for neutral and stable conditions. So we obtain the following expressions for wind velocity:

In case of neutral stabilitywith , we get

(28)

In case of stable flowwith , we get

(29)

In case of stable flowwith , we get

(30)

In the planetary boundary layer, above the surface layer, power law scheme has been employed.

(31)

where, is the geostrophic wind, the wind at , the top of the surface layer, the mixing height and is an

exponent which depends upon the atmospheric stability. The values for the exponent , obtained from the

measurements made from urban wind profiles [34], as follows:


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Wind velocity profiles given by equations (28) - (31) due to [30] are used in this model.

4.NUMERICAL METHODIt is to be noted that it is difficult to obtain the analytical solution for the coupled equations (1) and (6) because of thecomplicated form of wind speed and eddy diffusivity profiles considered in this model. Hence, we have used thenumerical method based on the Crank-Nicolson finite difference scheme to obtain the solution. The dependent variable

is a function of the independent variables and i.e., . First, the continuum region of interest is

overlaid with or subdivided into a set of equal rectangles of sides and , by equally spaced grid lines, parallel to

axis, defined by , and equally spaced grid lines parallel to axis, defined by

respectively. Time is indexed such that where is the time

step. At the intersection of grid lines, i.e. grid points, the finite difference solution of the variable is defined. The

dependent variable is denoted by , where and indicate the value at a

node point and value at time level respectively.

We employ the implicit Crank-Nicolson scheme to discretize the equation (1). The derivatives are replaced by thearithmetic average of their finite difference approximations at the and time steps. Then equation (1) at

the grid points and time step can be written as

(32)

This analog is actually the same as the first order correct analog used for the forward difference equation, but is nowsecond order-correct, since it is used to approximate the derivative at the point .

We use the backward differences for advective term in the primary pollutant equation. i.e

(33)

(34)

(35)

Also, for the diffusion term, we use the second order central difference scheme

Hence,


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(36)

Similarly,

(37)

Substituting equations (34) to (37) in equation (32) and rearranging the terms we get the finite difference equations forthe primary pollutant in the form

(38)

for each , for each

where,

and are the values at and respectively and x is the value of at .Equation (38) is true for interior grid points. At the boundary grid points we have to use the boundary conditions (2) to

(5).

The initial condition (2) is

The condition (3) becomes

The boundary condition (4) can be written as

(39)

for and

(40)

for

The boundary condition (5) can be written as(41)

The above system of equations (38) to (41) has a tridiagonal structure and is solved by [35].


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Similarly the finite difference equations for the secondary pollutant sC can be obtained as

(42)

for ,

where,

The initial and boundary conditions on secondary pollutant sC are

for

for , (43)

-

(44)

Vg is the mass ratio of the secondary particulate species to the primary gaseous species which is being converted.The system of equations (42) to (44) also has tridiagonal structure but is coupled with equations (38) to (41). First, thesystem of equations (38) to (41) is solved for , which is independent of the system (42) to (44) at every time step n.

This result at every time step is used in equations (38) to (41). Then the system of equations (42) to (44) is solved forat the same time step n. Both the systems of equations are solved using Thomas algorithm for tri-diagonal

equations (38) to (41) and (42) to (44). Thus, the concentration for primary and secondary pollutants is obtained.An important question concerning computational solutions is what guarantee can be given that the computationalsolution will be close to the exact solution of partial differential equation and under what circumstances thecomputational solution will coincide with the exact solution. The second part of this question can be answered byrequiring that the approximate or computational solution should converge to the exact solution as the grid spacing

x , and t shrink to zero. However, convergence is very difficult to establish directly and therefore an indirectroute as indicated below can be adopted.

Figure 2Solution of partial differential equationsThe indirect route requires that the system of algebraic equations formed by the discretization process should beconsistent with the governing partial differential equation. Consistency implies that the discretization process can bereversed through Taylor series expansion to recover the governing partial differential equations. In addition, the

algorithm is said to be convergent, if the approximate solution approaches the exact solution of the partial differentialequations, for each value of the independent variable as the grid spacing tends to zero. Convergence can be establishedby Lax Equivalence theorem Given a properly posed linear initial value problem and a finite difference approximationto it that satisfies the consistency condition, stability is the necessary and sufficient condition for the convergence


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Consistency is necessary if the approximate solution is to converge to the exact solution of the partial differentialequations under consideration. Stability is the tendency for any spontaneous perturbation (such as round-off error) inthe solution of the system of algebraic equations to decay. The concept of stability is concerned with the growth ordecay of errors introduced at any stage of the computation. In this context, errors referred to are not those produced byincorrect logic but by those which occur because the computer cannot give answers to an infinite number of decimal

places. In practice each calculation made on the computer is carried out to a finite number of significant figures whichintroduces a round-off error at every step of the computation. A particular method is stable if the cumulative effect ofthe entire round off errors produced in the application of the algorithm is negligible. Therefore we will now carry outconsistency and stability analysis of the finite difference scheme to solve the partial differential equation.

4.1 Consistency analysis of the governing equation

We assume that the pollutants do not undergo removal mechanisms, chemically inert, constant eddy diffusivity andwind velocity. Under these assumptions the governing partial differential equation (1) reduces to

(45)

We have applied a forward difference scheme for time derivative and backward difference for advective term. For thediffusion term we have used second order central difference scheme for the above equation. Thus we get

(46)We have

(47)

(48)

(49)

(50)

(51)

Substituting equations (47) to (51) in equation (46) and as we have

We get the original partial differential equation. Hence the implicit finite-difference Crank-Nicolson scheme used for

this model to obtain the solution is consistent.4.2 Stability analysis of the governing equation

Now we shall discuss the stability analysis of the governing equation


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We have used the implicit Crank-Nicolson scheme to discretize the equation (45). The derivatives are replaced by thearithmetic average of their finite difference approximations at the nth and (n+1)thtime steps. Then equation (45) at thegrid points(i, j) and time stepn+1/2can be written as

We have used forward difference for time derivative, backward difference for advection term and second order centraldifference scheme for the diffusion term.

(52)

Each Fourier component of the solution is written as

where, is the amplitude function at time-level n of the particular component whose wave numbers are (wave

length ), (wave length ) and .

Define the phase angles, and , .

Then

Similarly,

Substituting in equation (52) we have

Canceling the common term jiIe , we get

On simplification we obtain

(53)We evaluate the amplification factor G from the equation

where

i.e (54)


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Note that, i.e., the amplitude factor varies for each Fourier components. If solutions are to remainbounded, we must have

for all and. (55)

From equations (54) and (55), we have, which is satisfied for all possible and i.e for all possible

Fourier mode. Thus the scheme is unconditionally stable.We have analysed the above numerical scheme for consistency and stability. Consistency is investigated for the implicitdiscretization of the governing diffusion equation. The derivatives are replaced by the arithmetic average of its finitedifference approximations at thenth and (n+1)thtime steps. The resulting equation coincides with governing diffusionequation as tends to zero. Hence the implicit finite difference scheme used for the solution of this model isconsistent. We have used the Von Neumanns method to study the stability analysis. Using Fourier mode analysis it isshown that the employed numerical scheme is unconditionally stable. Therefore the whole scheme is unconditionallystable for equations (1) and (6).

4.3 Residual

The difference between the exact solution and the approximate solution is called the residual. We discuss the residualwhen the concentration of the pollutant reaches the steady state. When the system has reached the steady state, the timederivative of the physical quantity tends to zero. When the numerical solution obtained is not exactly steady, the time

discrete derivatives will not be precisely zero. The non zero value is called residual. The magnitude of the residualindicates the accuracy of the method. When Computational Fluid Dynamics experts are comparing the relative meritsof two or more different algorithms for a time marching solution to the steady state, the magnitude of the residuals andtheir rate of decay are often used as figures of merit. The algorithm which gives the fastest decay of the residuals to thesmallest value is usually looked upon most favorably.In this problem we obtain the steady state residual to indicate the accuracy of the Crank - Nicolson method. Theconcept of residual can be understood from the following procedures.Consider the governing equation,

(56)

When an upwind version of the Crank - Nicolson method is applied to this equation, we get

(57)

When the steady state is reached the time derivative of the physical quantity should approach zero if the solution isexactly steady. Since the numerical values of the derivative are not precisely zero, the non zero value of the timederivative is called the residual. This is the left hand side of the equation (56) which is computed from

(58)

As time progress and as the steady state is approached , the time derivative (58) should approach zero. Since the

numerical value of the left hand side of equation (57) are not precisely zero they are called residuals [36]. We havecomputed the residuals obtained after every time step against the number of time steps and analyzed in figure 3. It isseen that the residuals settle to around 10-6.

0 2 0 0 0 4 0 0 0 6 0 0 0 8 0 0 0 1 0 0 0 0

1 E -7

1 E -6

1 E -5

1 E -4

1 E -3

0 . 0 1

0 . 1

1

Residual

T im e

Figure 3. Plot of residual versus time.

5.RESULTS AND DISCUSSIONA numerical model for the computation of the ambient air concentration of the pollutant along the down-wind and thevertical directions emitted from an area source along with the point source on the boundary with the removal


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mechanism and the transformation process has been presented. The numerical model permits the estimation of theconcentration distribution for more realistic meteorological conditions. An area source is an emission source which isspread out over the surface of the city with finite downwind and infinite crosswind dimensions where major sourcebeing vehicular exhausts due to traffic flow. We have taken a point source arbitrarily at the beginning of the city. Thegrid lines are not passing through the point source and it is difficult to adopt point source in numerical method.

Therefore we have distributed the concentration of point source equally to its two neighboring grid points. We haveconsidered grid size as along -direction and along -direction.Figures 4 and 5 demonstrates the concentration of the primary pollutant with respect to height for different values ofdistance with varying values of chemical reaction rate coefficient for the stable and the neutral atmospheric conditions.Since we have considered the point source at and at , the concentration of the pollutant is maximumaround 20.5 m height in both the atmospheric conditions. As the distance increases, the concentration of the pollutantdecreases due to removal mechanisms or transformation processes. In the stable atmospheric condition, near the groundlevel the initial concentration of the pollutant is around 30 and then it slowly decreases. It reaches zero around15 m height and then again increases up to 20.5 m height and then rapidly decreases in the stable case. From Figures4(a) and 4(b), it is understood that as the value of chemical reaction rate coefficient increases there is no much changein the concentration of primary pollutant near the point source for stable atmospheric condition This behavior isbecause the increase in the value of the chemical reaction rate coefficient is too smaller when compared to thecontinuous emission of the point source strength. The similar effect is observed in the neutral atmospheric condition. Inthe neutral case, the concentration of the primary pollutant is less comparing to the stable case for the same values ofdistance. The concentration of the pollutant reaches zero in stable case around height and

0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0

0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

3 5 0

Concentration

H e ig h t

P r im a ry p o l lu ta n t

k =0 .0 0 0 0 8 x =7 5

x = 1 5 0

x =2 2 5

Vd=0 .0 0 5

( a )

0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0

0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

3 5 0

Concentration

H e ig h t

P r im a ry p o llu ta n t

x =7 5

x =1 5 0

x =2 2 5

k =0 .0 1V

d=0 .0 0 5

( b )

Figure 4. Concentration of primary pollutant with respect to height for different distances with varying values of

chemical reaction rate coefficient for stable case.

0 2 0 4 0 6 0 8 0 1 0 0 1 2 0

0

2 0

4 0

6 0

8 0

1 0 0

1 2 0

1 4 0

1 6 0

Concentration

H e ig h t

x =7 5

x =1 5 0

x =2 2 5


k =0 .0 0 0 0 8

Vd=0 .0 0 5

( a )

0 2 0 4 0 6 0 8 0 1 0 0 1 2 0-2 0

0

2 0

4 0

6 0

8 0

1 0 0

1 2 0

1 4 0

Concentration

H e ig h t

x =7 5

x =1 5 0

x =2 2 5

P ri m a ry p o llu ta n t

k =0 .0 1V

d=0 .0 0 5

( b )

Figure 5. Concentration of primary pollutant with respect to height for different distances with varying values of

chemical reaction rate coefficient for neutral case.

0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0

0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

3 5 0

Concentration

H e ig h t

x =7 5

x =1 50

x=2 2 5


Vd=0 .01

k=0 .00 0 08

0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0

0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

3 5 0

Concentration

H e ig h t

x =7 5

x=1 5 0

x =2 2 5


V d =0 .2 5

k =0 .0 0 0 0 8

Figure 6. Concentration of primary pollutant with respect to height for different distances with varying values of dry

deposition velocity for stable case.around height in the neutral case. This behavior is because the neutral atmospheric condition enhances thevertical diffusion of the pollutant to the greater heights.

In Figures 6 and 7, the concentration of the primary pollutant with respect to height for different distances with varyingvalues of the dry deposition is analysed for the stable and the neutral atmospheric conditions. As the point source isconsidered at the beginning of the city region and at 20.5 m height, the concentration is maximum at that height andthen the concentration decreases as the distance increases. It reaches zero at 35 m height in the stable case. In the stable


14/18




case, the ground level concentration of theprimary pollutant at is around 35 for . But when, the ground level concentration of the primary pollutant becomes zero at . This clearly indicates that

as the value of the dry deposition velocity increases, the ground level concentration of the pollutant decreases. Similareffect is observed in the neutral case. But the concentration of the primary pollutant becomes zero at 100 m height inthe neutral atmospheric condition. The concentration of the primary pollutant is less in the neutral case comparing to

the stable case for the same values of distance. Also as the value of the dry deposition velocity increases there is nomuch variation in the concentration of the primary pollutant near the point source for the stable and the neutralatmospheric conditions. This behavior is because the increase in the value of the dry deposition velocity is negligiblewhen compared to the continuous emission of the point source strength and we have considered the dry depositionvelocity at the ground level.

0 2 0 4 0 6 0 8 0 1 0 0 1 2 0

0

2 0

4 0

6 0

8 0

1 0 0

1 2 0

1 4 0

1 6 0

Concentration

H e ig h t


x =7 5

x =1 5 0

x =2 2 5

Vd=0 .0 1

k =0 .0 0 0 0 8

0 2 0 4 0 6 0 8 0 1 0 0 1 2 0

0

2 0

4 0

6 0

8 0

1 00

1 20

1 40

1 60

Concentration

H e igh t

P r im a ry p o llu ta nt

x = 7 5

x = 1 50

x = 22 5

Vd=0 .2 5

k =0 .00 0 08

Figure 7. Concentration of primary pollutant with respect to height for different distances with varying values of dry

deposition velocity for neutral case.

0 5 10 15 20 25 30 35 40

0.0000

0.0004

0.0008

0.0012

0.0016

0.0020

0.0024

0.0028

Concentration

Height

S econ dary pollutant

x=75

x=150

x=225

Vd=0.01

k=0.00008

0 5 10 15 20 25 30 35 40

0.0000

0.0004

0.0008

0.0012

0.0016

0.0020

0.0024

0.0028

Concentration

Height

Se condary pollutant

Vd=0.25

k0.00008x=75

x=150

x=225

Figure 8. Concentration of secondary pollutant with respect to height for different distances with varying values of dry

deposition velocity for stable case.

0 20 40 60 80 100 120

0.0000

0.0004

0.0008

0.0012

0.0016

0.0020

0.0024

Concentration

Height

S econdary po llutant

V d=0.0 1k=0.00008

x=75

x=150

x=225

0 20 4 0 60 80 100 120

0.0000

0.0004

0.0008

0.0012

0.0016

C

oncentration

H ei ht

S econdary pol lutant

Vd=0.25

k=0.00008x=75

x=150

x=225

Figure 9. Concentration of secondary pollutant with respect to height for different distances with varying values of dry

deposition velocity for neutral case.Figures 8 and 9 represent the concentration of the secondary pollutants versus height for varied distance with differentvalues of the dry deposition velocity for the stable and the neutral cases. In the stable case, when , initially asthe height increases the concentration of the secondary pollutant decreases. Again the concentration increases up to theheight 20.5 m and then it decreases and reaches zero at 38 m height. When the value of the dry deposition velocityincreases to 0.25, the ground level concentration of the secondary pollutant becomes zero at the beginning. Theconcentration increases in the downwind distance up to 20.5 m height and then it decreases. It is observed that theconcentration of the secondary pollutant decreases as the distance increases in both the stable and the neutralatmospheric conditions. In the neutral case, the ground level concentration of the secondary pollutant is low ascompared to that in the stable case when . When , the concentration increases up to 20.5 m height


15/18




then it decreases and reaches zero around 110 m height. Therefore comparing to the stable case, the concentration ofthe secondary pollutant reaches zero at the greater heights in the neutral case. Also as the value of dry depositionvelocity increases there is no much effect of the secondary pollutant near the point source for the stable and the neutralatmospheric conditions. This behavior is because the dry deposition is introduced at the ground level and increase inthe value of the dry deposition velocity is too smaller when compared to the continuous emission of the point source

strength.From Figures 10 and 11, the concentration of the primary and the secondary pollutants with respect to distance fordifferent heights for the stable and the neutral atmospheric conditions is studied. In the stable case the concentration ofthe primary pollutant increases up to and it decreases outside the city because there is no area source beyondthe city region. As the height increases, the concentration of the primary pollutant decreases. The concentration of theprimary pollutant is maximum near the point source and at the end of the city region. The concentration of thesecondary pollutant is zero at the beginning of the city region and it increases with respect to distance. Theconcentration of the secondary pollutant is more in the outskirt of the urban city at the ground level when compared toinside the city region. In the neutral case the similar effect is observed as in the case of the stable atmosphere for boththe primary and the secondary pollutants. But the concentration of the pollutants is less in the neutral case whencompared to the stable case for the same values of height.

0 2 0 0 0 4 0 0 0 6 0 0 0 8 0 0 0 1 0 0 0 0 1 2 0 0 0

0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

Concentration

D i s ta n c e

z = 2

z =1 2

z =2 2

z =3 0

P r im a ry p o llta n t

0 2 0 0 0 4 0 0 0 6 0 0 0 8 0 0 0 1 0 0 0 0 1 2 0 0 0- 0 .0 2

0 .0 0

0 .0 2

0 .0 4

0 .0 6

0 .0 8

0 .1 0

0 .1 2

0 .1 4

Concentration

D is ta n c e

S e c o n d a ry p o llu ta n t

z = 2

z =1 2

z =2 2

z =3 0

Figure 10. Concentration of primary and secondary pollutants with respect to distance for different heights for stable

case.

0 20 0 0 4 00 0 6 00 0 8 00 0 10 00 0 12 00 0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

10 0

11 0

Concentratio

n

D istance

z=22

z =2

z=12

z=30

P rim ary po llutan t

0 2 0 0 0 4 0 0 0 6 0 0 0 8 0 0 0 1 0 0 0 0 1 2 0 0 0

0 . 0 0 0

0 . 0 0 2

0 . 0 0 4

0 . 0 0 6

0 . 0 0 8

0 . 0 1 0

0 . 0 1 2

0 . 0 1 4

0 . 0 1 6

0 . 0 1 8

0 . 0 2 0

Concentration

D is tan ce

z =2

z =1 2

z =2 2

z =3 0

S e c o n d a r y p o l lu t a n t

Figure 11. Concentration of primary and secondary pollutants with respect to distance for different heights for neutral

case.The concentration contours of the primary and the secondary pollutants are drawn in Figures 12 and 13 for both thestable and the neutral atmospheric conditions. It is noted that the concentration of the primary pollutant attains peakvalue at the downwind end of the source region. Whereas, the concentration of the secondary pollutant attains its peakvalue at the outside of the city region in the downwind direction. The secondary pollutants are more concentrated awayfrom the ground and are spread out evenly throughout the region. This is due to the chemical reaction taking place inthe atmosphere converting the primary into secondary pollutants. The magnitude of the concentration of the primaryand the secondary pollutants is higher in the stable case and lower in the neutral case. This behavior is because theneutral atmosphere carries the pollutants to the greater heights and thus the concentration is less.

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

1 . 76 . 07 0 .5 7

6 2 .7 3

6 2 .7 3

5 4 .8 94 7 .0 5

3 9 .2 0

3 1 .3 6

2 3 .5 2

1 5 .6

7 .8 4 1

2 0 0 0 4 0 0 0 6 0 0 0 8 0 0 0 1 0 0 0 0

1 0

2 0

3 0

4 0

5 0

6 0

Height

D is ta n c e

P r im a ry p o l lu ta n t

( a )

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

6 . 23 8 .4 13 1 . 3 4 2 7 .8 0

2 4 .2 62 0 .7 3

1 7 .1 9

1 3 .6 5

1 0 .1 1

6 .5 7 5

2 0 0 0 4 0 0 0 6 0 0 0 8 0 0 0 1 0 0 0 0

2 5

5 0

7 5

1 0 0

1 2 5

1 5 0

1 7 5

2 0 0

Height

D is ta n c e

P r im a ry p o l lu ta n t( b )

Figure 12. Concentration contours of primary pollutant for (a) stable and (b) neutral atmospheric conditions


16/18




2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 .6 E -02 .4 E - 0 2

2 .2 E - 0 2

1 .9 E -0 2

1 .7 E - 0 2

1 .4 E - 0 21 .2 E -0 2

9 .6 E - 0 3

7 .2 E - 0 3

2 .4 E - 0 3

2 0 0 0 4 0 0 0 6 0 0 0 8 0 0 0 1 0 0 0 0

1 0

2 0

3 0

4 0

5 0

Height

D i s ta n c e

S e c o n d a ry p o llu ta n t

( a )

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

4 .3 E -0 3

3 .6 E -0 3

2 .9 E -0 32 .1 E - 0 3

1 .4 E - 0 3

7 .9 E -0 3

7 .2 E -0 36 .4 E -0 3

5 .7 E -0 3

5 .0 E -0

Advection - Diffusion numerical model of air pollutants emitted from an urban area source with...

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Transcript of Advection - Diffusion numerical model of air pollutants emitted from an urban area source with...