Local Air Quality Modeling,
AIM/Air
The 9th AIM International Workshop
12-14, March 2004, at NIES
Graduate School of Global Environmental Studies
Kyoto University

Takeshi Fujiwara

Outline of AIM/Air+ AIM/Air is a program package to calculate thepollutant concentration based on plume and puff
diffusion models.
+ Area source (AS) and Large Point Source ( LPS)
can be dealt with. The emission data from
“AIM/Local” are directly available by using
converter “A-GIS”.
+ Target size is from city to country.
+ AIM/Air has friendly user interface and runs on
both PC’s Windows and Linux.

Characteristics of AIM/Air+ Properties of emission, such as amount per year, gas
temperature, and gas flow, are definable by each LPS orcell of AS.
+ Emission profile is definable. Not only change ofemission in a day, in a week and in year but also specialterms (such as holiday and off-time in equipmentmaintenance) are considered.
+ Standard meteorological data (ECMWF） is available.
Use of the meteorological data locally measured iseffective to increase accuracy of diffusion analysis.
+ An effective algorithm to reduce computational time isadopted.

Model Equations
Plume model (Wind velocity >= 1 m/s)
 y 2    ( z − He) 2  ( z + He) 2 ⋅ exp −・ exp −C ( x, y , z ) = + exp−
22
 2σ 2   
2πσ yσ z u2σ2σy  zz



Qp

Puff model (Wind velocity < 1 m/s)
 u2x2  u2  1 
2π ux
−
 ⋅[ 2 1 +⋅ exp 2 2  ⋅ erfc −⋅C ( x, y , z ) =exp
 2α η  2α 2  η αη −( 2π ) 3 γ−  − Qp u2x2 1 2π ux+ 2 1 +⋅ exp 2 2  ⋅ erfc − 2α η αη +η + + α2η = R + 2 ( z − He )2γ
2−2α2η = R + 2 ( z + He )2γ
2+2erfc(W ) =2∞2αη − ux]
2αη + ux

exp(−t )dtπ ∫W2Emission
projection

AIM/Air General Data Flow Diagram

AIM/Local
A-GIS

Grid databy rasterformat

AGIS.rst

Emissionpatterns

Target areaeditEpat

editGmap

Change in
A day,
A week,A year,And
Special terms

1.2
10.8
0.6
0.4
0.2
0Mon

convAGIS
epat.airgmap.air

TueWedThu

FriSatSun

Meteorological data

agis.air
ECMWF
LPS

AS

Local measurement
local.air

readGRBX
Integrationof LPSemission data

Stability
calculation
for LPS

editLPS

editAS

emitLPS.air

emitAS.air

stabLPS

stabAS

stabLPS.air

stabAS.air

Integrationof AS
emission data

u.air
u.air
u.air

Stability
calculation
for AS
Diffusion
calculation

diffB

diff.airConcentration

viewCont

Viewer(Connect to health impact assessment module)

Emission Pattern Editor

Change in a year
Changein a day
by monthby hour

ChangeinChange
in a week
Specialbywhat terms
day

1.2
10.8
0.6
0.4
0.20Mon

TueWedThuFriSatSun

AS Emission Editor
3) SetTarget Area
2)Load Emission
pattern Database4) (click) Select A
Emission Pattern…..
1) Load Map Data5) (and click) Assign
the Emission Pattern
To This Cell.

LPS Emission Editor3) (click) Select A
Emission Pattern…..

1) Load Emission
pattern database4) (and click) Assign
the Emission PatternTo This Cell.

2) Load LPS data

Application
 AIM/Air was applied to assess healthimpact of SO2 in Beijing.

Air Quality Level in China
The 1st level: Nature protection zone, scenic zone.
Day-averaged SO2 concentration: 50μg/m3
The 2nd level ：Residential area, the area mixed
with commercial, transportation and residentialarea, cultural area , usual industrial area, andagricultural area
Day-averaged SO2 concentration ： 150μg/m3
The 3rd level：Specified industrial area. Dayaveraged SO2 concentration ：250μg/m3

Pollution Level of cities in China
Because of drastic development of economics inChina to identify the health impact caused by SO2
is significantly important.
In 343 cities researched in China,
The number of cities where SO2 concentration isabove the standard value of the 3rd level airquality：
107 cities(31.2%)
Above the 2nd level and below the 3rd level ：120cities(35.0%)
If the 2nd air quality level is achieved 178,000 of death will be
avoided (World Bank)

Procedure
TARGET POLLUTANT
Pollutant

SO2

EMISSION PROJECTION(AIM/Local)
ASLPS
CementNon-Ferrous Metal
Iron & SteelPower Generation

Commerce
Transportation
PublicOthers
A-GIS

Emission patterns(AIM/Air)METEOROLOGY DATAWind velocity
Temperature

Interpolation of
meteorology data
(1km mesh,1hrs interval)

DIFFUSION CALCULATION

Calculation of
atmospheric stability

Diffusion model for AS
Diffusion model for LPS

Solar radiation
Cloud cover
Geo potential
Surface Geo potential

Calculation ofeffective stack height(0.5°mesh, 6hrs interval)
Population map

HEALTH RISK ASSESSMENT
Concentration-Response Function

Target Area
Beijing(China)
1,600km2
Target time extent：
Jan 1, 〜Dec. 31, 2000
Target pollutant：SO212
3456Measurement points
観測点
Che Gong Zhuang
Qian MenDong Si
The Temple of Hea
Olympic Center
Agricultural Museum

516324

Emission Source (AIM/Local)
AS(Area Source)
LPS(Large Point Source)
Cement sector
Steel and iron sector
Non-ferrous metal sector

GDP by secondary industry sectionin each district
Population density in each 30
seconds meshPower generation sector
Commerce sector
Transportation sector

GDP by third industry section ineach district
Population density in each 30
seconds mesh.

Public sector
Other sector

Population density

Emission pattern (1)Change in day

Power generation andpublic sectors

Industry andcommerce sectors

Zero during
19:00〜8:00

0.0 4

Weight
加重Constant during
9:00〜19:00

0.0 6

0.0 2

0.0 00Change in week

612
時刻
Time

1824

Industry sector：constant during Mon. to Fri.
and zero on Sat. and Sun.

Emission Pattern (2)Change in year

Commerce and public sectors(frequent use of heater)
Em issio n r at e by se c t o rCommerce
Pu blic

Emission from heater
Emission from every equipment=39%(public sector)

MonthJan .
Fe b.
M ar .
Apr .
M ay

0.447
0.169
0.0660.011
0.009

0.243
0.121
0.076
0.052
0.051

=89%(commercial sector)

Ju n .
Ju l.
Au g.
Se p.
Oc t .
No v.
De c .

0.009
0.009
0.009
0.009
0.013
0.071
0.178

0.051
0.051
0.051
0.051
0.052
0.078
0.125

Special terms
新年 ：Jan. 1

春節：Feb. 5〜7

労働祭：Apr. 29〜May 5

国慶祭： Sep. 29〜Oct. 3.

Health Impact Assessment
The relationship between SO2 concentration
averaged in 48 hrs and daily mortality

Daily Mortality= [ y0 ⋅ (exp(− β ⋅ ⊿SO2 ) − 1)] ⋅ popy0: rate of death caused by any events except accident

β：SO2 coefficient⊿ SO2 ：The difference between projected SO2 concentration whichis averaged in 48 hrs and the regulation value of the 2nd gradestandard.
Using the daily mortality how many death can be avoided if
the concentration is regulated under the standard value ofthe 2nd level air quality is calculated.

Winter season
Relationcoefficient: 0.769

500400(μg/m 3 )Comparison between
measurement andcomputation of dayaveraged concentration.

SO 2 日平均濃度観測値
Computationalvalue

Result from diffusion simulation(1)
30020010000100200300400500

3SO 2 日平均濃度推計値(μg/m )Measurement
value(environmental annual
report of 1998)(μg/m )

503

Summer season
Relationcoefficient 0.892

Computationalvalue
SO 2 日平均濃度観測値

60403020100010203040

3
SO 2 日平均濃度推計値(μg/m)
Measurement
value

5060

Result from diffusion simulation (2)Contribution of the day-averaged SO2 concentration by
sector at a cite of high population density
Cement
セメント

Power

発電
Gen.

Iron

鉄鋼
SteelNon

非鉄金属
Ferrous

Come

商業
rce

Trans

運輸
port

Public民生Others
その他

SO 2 日平均濃度(μg/m 3 )

1000
800
600
400

2nd gradeof air quality
150(μg/m3)

200
01/1

3/1

5/1

7/1
日付

9/1

11/1

Result from Diffusion Simulation (3)Histogram of day-averaged SO2 concentration
全部門
All sectors

Power gen.
発電

Commerce
商業Public
民生

Othersその他

3Day-averagedSO
SO22 日平均濃度(μg/mconcentration)

1200

800

The 3rd level 250μg/m3
400

The 2nd level 150μg/m30060

43days120

91days180
日数days240

300360Result from Diffusion Simulation (4)The number of days which day-averaged SO2 concentration isabove the standard value of the 2nd level air quality# o f d ays
ab o vest an d ar d012345678910111213141517182129

Mo n thJan. Feb. Mar. Apl. May Jun. Jul. Aug. Sep. Oct. Nov. Dec.
86.09 97.09 99.25 99.84 99.78 99.81 99.75 99.91 99.69 99.75 99.37 99.5
8.054 1.88 0.501 0.063 0.157 0.063 0.157 0.031 0.219 0.157 0.439 0.345
3.322 0.282 0.094
00 0.031
0 0.031 0.031 0.031 0.031 0.031
0.721 0.188
0 0.0310 0.0630000
0 0.0310.407 0.157
00 0.031 0.031 0.031 0.031 0.031
0000.501 0.125
00 0.031
0 0.031000 0.063 0.031
0.094 0.031 0.094 0.031
00 0.031
0 0.0310000.094 0.031 0.031
00000
0 0.031 0.031 0.031
0.251 0.063
0000000 0.031000.1250000
00000000.063 0.031
0 0.031000000 0.031
00.0310000000000 0.031
0.063
000000000000.031 0.063 0.031
0000000000000000000 0.031
00.031 0.031
00000000000.031
000000000000.031 0.031
00000000000.031
000000000000.031
00000000000

The maximum number of days which is above the 2nd standard is 104 days.

Result from Impact assessment
The total number of avoidable death in the target area andthe maximum number of the avoidable death in whole cells,
by monthMonthJan .
Fe b.
M ar .
Apr .
M ay
Ju n .
Ju l.
Au g.
Se p.
Oc t .
No v.
De c .

T o t al587.14
22.09
3.57
0.72
0.39
0.79
2.28
0.31
1.15
0.82
6.6
1.79

T h e m axim u m in c e lls
206.78
11.17
2.09
0.72
0.39
0.41
1.38
0.31
0.73
0.82
6.02
1.77

Unit： person’s death

If SO2 concentration in
Beijing is regulated
under the standard
value of the 2nd gradeof air quality in China,
the total number of
avoidable death in year
2000 is approximately

626.9

Conclusion
Air quality modeling and simulation tool AIM/Air wasdeveloped.
 By using this tool concentration of air pollutant can becalculated from the information of emission source thatis resulted from AIM/Local.
 Proposed algorithm for quick calculation and userinterface enables to run diffusion calculation both on
PC’s Windows and Linux.
 This tool was applied to project air quality of Beijing.
Moreover, daily mortality was assessed.
Thank you