[PPT] - Local Air Pollution Modeling Local Air Pollution Modeling AIM/Air PowerPoint Presentation

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Local Air Pollution Modeling Local Air Pollution Modeling AIM/Air AIM/Air

Takeshi Fujiwara and Yuzuru Matsuoka Takeshi Fujiwara and Yuzuru Matsuoka 2003/03/13 2003/03/13 The 8 The 8th

th AIM International Workshop

AIM International Workshop

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AIM/Air AIM/Air

Introduction of an air quality modeling in

the framework of AIM AIM family

One of supplementary models of

AIM/Enduse AIM/Enduse

Consolidated with the emission inventory

and energy bottom-up model, multi-scale multi-species model

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Framework of AIM/Air

Source recepter matrix

Air quality

Receptor models

Human health impacts Soils acidification /eutrophication Forests acidification /eutrophication Water bodies acidification /eutrophication In door receptor model

Source models AIM/Local and Inventory

Residential Transport Commercial Industry Energy

Emission Inventory

Air Model Long range transport (LRT) model LPS model Area Source model

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Characteristics

Sources: Large point sources (tall stack >200m)

and area sources. Line sources are included in area sources.

Target pollutants: SO2, NO2, SPM
Coupling of models: Point source model (LPS),

area source model (AS) and long-range transport model(LRT)

Multi-scale description: x km(LPS) + mx

km(AS) + mnx km(LRT) grids (integer m,n)

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Modeling concept(1)

LPS (plume and puff) model AS(Euler) model Long range transportation model

Height 1 Height 2 Height 3

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3 Layered Euler model 1 Layered AS model (Euler) 10km 50km

Vertical Relation between AS model and LRT model

1st layer (~1000m) 2nd layer (~3000m) 3rd layer (~5000m) 50km LPS model (plume and puff)

Modeling concept(2)

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Modeling concept(3)

50km LRT cell Relation among LPS grid, AS grid and LRT grid 30km 30km 10km 50km 10km AS cell LPS cell

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MASCON Wind velocity is interpolated based on air mass balance ECMWF Meteorology data

f the world.

AS model A diffusion model in the lower mixing layer for pollutants emitted from area sources LRT model A model for Long-Range Transportation of air pollutants. LPS model Plume and Puff model for pollutants emitted from large point sources GIS Geographic Information System LPS data Large point sources data AS data Area sources data

General Flow of AIM/Air

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AIM/Air Data & Process

prep.d wind.lrt wind.as u.d v.d w.d geo.d sg.d rad.d cloud.d temp.d emit.lps emit.as

diffusionLRT diffusionAS diffusionLPS

ECMWF GRIBEX

interpAS interpLRT balanceAS balanceLRT ReadGRIB wind.lps interpLPS stabLPS

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Data & Process (Weather)

prep.d u.d v.d w.d geo.d sg.d rad.d cloud.d temp.d

ECMWF GRIBEX

ReadGRIB

Wind velocity(u,v,w) Geo potential Surface Geo potential Precipitation Total cloud cover Solar radiation Temperature

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Data & Process (LPS)

u.d v.d w.d geo.d sg.d rad.d cloud.d temp.d emit.lps

diffusionLPS

wind.lps interpLPS stabLPS

LPS location Stack height Emission intensity Gas flow rate Interpolation of wind velocity at LPS site and stack height Calculation of atmospheric stability

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Data & Process (AS)

wind.as u.d v.d w.d geo.d sg.d emit.as

diffusionAS

interpAS balanceAS

Emission intensity at each cell Primary interpolation of wind velocity Secondary interpolation of wind velocity using mass balance equation (MASCON)

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Data & Process (LRT)

prep.d wind.lrt u.d v.d w.d geo.d sg.d emit.lps emit.as

diffusionLRT

interpLRT balanceLRT

Primary interpolation of wind velocity Secondary interpolation of wind velocity using mass balance equation (MASCON)

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Primary interpolation

3000m 1000m αhPa βhPa γhPa P r e s s u r e l e v e l 3000m 1000m αhPa βhPa

Surface Geopotential

γhPa P r e s s u r e l e v e l P r e s s u r e l e v e l

Interpolation Geopotential

( ) ( ) ( ) ( ) ( )

2 2 2 1 1

1 , , , , , z z y y x x z y x u z y x u

i i i i N i i N i i i i i

− + − + − = =

∑ ∑

= =

λ λ λ

( )

( ) ( ) { }

hPa a G hPa G hPa hPa G a G hPa G hPa G

u E E u E E E E a u

α β β α α β

× − + × − × − =

, , , , , ,

1

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LPS model (1)

Corresponding to tall stack emissions (larger than

100～200m). Emission input to this LPS model is not included in the AS model.

A plume model (windy) or puff model (no wind).
Complex terrain modification is similar to EPA’s

ISC3.

Calculate concentration at each cell (1km x 1km),

within 10 km to every directions near the emission sites, hour by hour through a year.

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LPS model (2)

( ) ( ) ( )

                  + − +         − −         − =

2 2 2 2 2 2

2 2 exp 2 exp 2 , ,

z e z e y z y P

H z H z y u Q z y x C σ σ σ σ πσ

Plume model x: downstream coordinate, y: horizontally transverse coordinate, z: vertical coordinate (representative height=1.5m, σy,σz： diffusion coefficients and calculated with the next equations, Qp: emission from LPS, u: wind velocity, He: effective height of stacks γy,γz,αy,αz: parameters given with Pasquill-Gifford diagram. He is given by the next CONCAWE equation. QH is a heat emission (cal/s), and uh is a wind velocity at the outlet

z y

x x

z z y y α α

γ σ γ σ ⋅ = ⋅ = , ( )

4 3 2 1

175 . T T q C Q u Q H H H H

g g p H h H e

− = = ∆ ∆ + =

−

ρ

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LPS model (3)

Puff model in case of no wind/weak wind where α and γ is given with Pasquill stability classification. In this case, He is given by Briggs equation.

( ) ( ) ( ) ( ) ( )

∫

∞ − + − + − + + − − − −

= + + + = − + + =                                  −         ⋅ + +                  −         ⋅ +        − =

W t e e P

dt e W H z y x H z y x ux x u ux ux x u ux u Q z y x C

2

1 erfc 2 erfc 2 exp 2 1 1 2 erfc 2 exp 2 1 1 2 exp 2 , ,

2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 3

π γ α η γ α η αη η α αη π η αη η α αη π η α γ π

8 3 4 1

4 . 1

−

      = ∆ dz d Q H

H

θ

(K/m) gradient re temperatu potential is dz dθ

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Euler Model(AS & LRT)

i i i v i h i h i i i i

Q R z c k z y c k y x c k x z wc y vc x uc t c + +       ∂ ∂ ∂ ∂ +         ∂ ∂ ∂ ∂ +       ∂ ∂ ∂ ∂ + ∂ ∂ − ∂ ∂ − ∂ ∂ − = ∂ ∂ ) ( ) ( ) (

P

C ⋅

･

S

x ∆

S

v

N

v

N

x ∆

･

E

C ⋅

･

W

C ⋅

N

C ⋅

･

S

C ⋅

W

y ∆

E

y ∆

W

u

E

u

Input and output through a cell

Equation

i

c

h

k

v

k

i

R

i

Q

Concentration Diffusion parameters Reaction terms

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Deposition of Sulfur

2 2 2 2 2

, , , , SO SO P SO

ut

SO in SO P

R Q E E z y x t C + + − = ∆ ⋅ ∆ ⋅ ∆ ⋅ ∆ ∆

4 4 4 4 4

, , , , SO SO P SO

ut

SO in SO P

R Q E E z y x t C + + − = ∆ ⋅ ∆ ⋅ ∆ ⋅ ∆ ∆

k: reaction rate of SO2→SO42 –

W: dry deposition ratio

PR: wet deposition rate

( ) { }

z y x kC z y x C PR z W R

SO P SO P SO P SO P SO P

∆ ⋅ ∆ ⋅ ∆ ⋅ − ∆ ⋅ ∆ ⋅ ∆ ⋅ ⋅ − ∆ − =