1

Prediction of Air Quality

over Tokyo Metropolitan Area

by Using the JCAP II

Air Quality Simulation System

Presented at the 6th Annual CMAS Conference, Chapel Hill, NC, October 1-3, 2007

Satoru Chatani1, Tazuko Morikawa1, Midori Ashizaki1,

Hideki Tashiro1, Hitoshi Kunimi1, Hiroshi Hirai2

and Satoshi Yamazaki3

1. Japan Petroleum Energy Center, Minato-ku, Tokyo, JAPAN

2. Japan Automobile Research Institute, Tsukuba, Ibaraki, JAPAN

3. Toyota Central R&D Labs., Inc., Nagakute, Aichi, JAPAN

2

Joint research project(Japanese version of the Auto-Oil program)

to improve air quality

Petroleum industryAutomobile industry

What is JCAP?(Japan Clean Air Program)

3

Objectives of Air Quality Studiesin JCAP II (2002.4 - 2007.3)

Develop the air quality modeling system and data;

- Simulate multi-scale air quality(from Asia to roadside)

- Reflect real-world driving conditions

- Contribute to the policymaking

- Open to the public (de facto standard in Japan)

Analyses using the system were report to the policymaking process.

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Structure of the Modeling System

Details of our system is presented at the poster session in tomorrow evening !!

Macro-scaletraffic flow model

Micro-scaletraffic flow model

Macro-scalevehicle emission inventory model

Micro-scalevehicle emission inventory model

Multiscaleair quality

model

Roadsideair quality

model

Meteorologicalmodel

Secondaryorganic aerosol

model

Emission inventoryexcept for vehicles

Aerosoldynamic model

Measurement of aerosol characteristics

Air pollution including nano-particles for roadside to urban / re

gional area

Evaluation of contribution from

vehicles

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0%

20%

40%

60%

80%

100%

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

Year

0

10

20

30

40

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

Year

Current Status of NO2 in Japan

Average conc. (ppb) NAAQS Attainment

(Polluted area specified by the automobile NOx-PM law)

Some roadside stations still exceed NAAQS of NO2.

Ambient Roadside

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0%

20%

40%

60%

80%

100%

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

Year

0

10

20

30

40

50

60

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

Year

Current Status of SPM in Japan(SPM : Suspended Particulate Matter, equivalent to PM7)

(Polluted area specified by the automobile NOx-PM law)

Average conc. (g/m3) NAAQS Attainment

NAAQS attainment varies (partly due to Asian dust).

Ambient Roadside

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Application of the Modeling System

Air quality model

CMAQ v4.6

Meteorological model

RAMS v4.4

Emission inventory

(Japan)

Vehicle : JCAP II

Other sources : EAGrid-2000 (Kannari, 2007)

(Outside Japan)

REAS (Ohara, 2007), GEIA (Granier, 2005)

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Target Domains of the Simulation

1,088km

1,02

4km

160km

176k

m

7,29

6km

7,296km

AsiaMesh 64 x 64 km

Japan G1Mesh 16 x 16 km

Japan G2Mesh 4 x 4 km

Main target area(Tokyo and surrounding area)

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Estimation of Vehicle Emissions

JCAP II Urban Motor Vehicle Emission Inventory Model

Emission processes : Running, Cold-start, Evaporative (Running loss,

Hot soak loss, Diurnal breathing loss), Road dust

and Tire wear

Pollutants : CO, NOx, SO2, THC, SPM, SO42-, NH3

Emission = Emission Factor * Traffic Amount

Category, model year, speed, deterioration,

temperature and humidity

Category, model year,

speed, mesh and hour< Basic equation (Running) >

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Traffic Amounts in Meshes

Digital Road Map (DRM)

No.

Length Traffic …

1 1.0 10,000 …

2 0.5 3,000 …

… … … …

Census data (by Government)

Matching

10 x 10 km(Whole Japan)

1x1 km(Around Tokyo)

Gridding by GIS

Traffic amountin meshes

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RSD for Identifying High-emitters

Real-world emission

measurement by RSD

(Remote Sensing Devices)

Average conc. and distribution (NO, PC)

Ratio of High-emitters was calculated and used for estimation.

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Distribution of Pollutant Emissions(Whole Japan, NOx in December)

Vehicles Other Anthropogenic

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Distribution of Pollutant Emissions(Around Tokyo, NOx in December)

Vehicles Other Anthropogenic

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Simulation Cases

Vehicle emission Boundary conc.

Case 1 Year 1999

Case 2 Year 2015

Case 3 Year 2015 + New regulation from year 2008 1

Case 4 Year 2015 + Excluding HE 2

Case 5 Year 1999 -50%

in Japan G1

Case 6 Year 1999 +50%

in Japan G1

1 : -50% and -25% of diesel NOx and PM EF from year 2008

Target period of the simulation : Nov. 1st to Dec. 10th, 1999

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Estimated NOx Emissions

0 100 200 300 400 500

Case 1

Case 2

Case 3

Case 4

NOx Emission (ton/day)

-44%

-52%

-59%

0 200 400 600 800 1000NOx Emission (ton/day)

-23%

-28%

-31%

Vehicles All Sources

Gasoline RE Diesel REGasoline ST Diesel ST

Stationary DomesticMobile Vehicles

Emission is largely reduced by replacement.

Excluding High-emitters are effective than new regulations.

(Summed over the target area)

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0 10 20 30 40 50 60

Case 1

Case 2

Case 3

Case 4

SPM Emission (ton/day)

-45%

-46%

-45%

0 20 40 60 80SPM Emission (ton/day)

-30%

-31%

-30%

Estimated SPM Emissions

Vehicles All Sources

Road dust Diesel RETire wear Diesel ST

Road dust and tire wear become major SPM sources.

New regulations have negligible effects.

Stationary DomesticMobile

VehiclesRoad dust

Tire wear

(Summed over the target area)

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Simulated NO2 Distribution

0 70 (ppb)

Observation Simulation

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Simulated SPM Distribution

0 80 (g/m3)

Observation Simulation

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Time Series of Concentrations

0

50

100

150

SP

M ( g

/m3)

SPM Kanda

0

50

100

150

12/90AM

12/912PM

12/100AM

12/1012PM

SP

M ( g

/m3)

SPM Shirokane0

20406080

100

NO

2 (

ppb)

NO2 Kanda

020406080

100

12/90AM

12/912PM

12/100AM

12/1012PM

NO

2 (

ppb)

NO2 Shirokane

(At stations within Tokyo metropolitan area)

Observation Simulation

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50% +50% -50%

Performance of NO2 SimulationMNE : Mean Normalized Error

MNB : Mean Normalized Bias

MNE MNB > 0 MNB < 0

Average within the target area

MNB : -17.9%, MNE : 21.1%

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100% +100% -100%

Performance of SPM SimulationMNE : Mean Normalized Error

MNB : Mean Normalized Bias

MNE MNB > 0 MNB < 0

Average within the target area

MNB : -51.4%, MNE : 53.3%

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34.5

28.5

27.2

26.3

0 10 20 30 40

Case 1

Case 2

Case 3

Case 4

Daily NO2 (ppb)

-17%

-21%

-24%

26.1

21.4

21.4

21.4

0 10 20 30Daily SPM (g/m3)

-18%

-18%

-18%

Predicted Pollutant Concentrations(Dec. 10th, 1999, Averaged over the target area)

NO2 SPM

Reduction of concentration is smaller than emission.

Why?

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Predicted Concentration of PM Components

(Dec. 10th, 1999, Averaged over the target area)

0 5 10 15 20 25 30 35

Case 1Case 2Case 3Case 4

Case 5Case 6

Daily SPM (g/m3)

SO42- NO3

- NH4+ EC OC Other PM2.5 SPM-PM2.5

Secondary components

Changes in vehicle emissions influence on primary components.

Secondary components are affected by transboundary transport.

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0

10

20

30

40

50

60

70

NOx Emission

NO

x (p

pb)

1,5,6

2

34

0

10

20

30

40

50

NOx Emission

NO

2 (

ppb) 2

4

3

1

5

6

0

5

10

15

20

25

NOx Emission

O3 (

ppb)

2

34

1

5

6

NOx Emission and Pollutant Concentrations

NOx NO2 O3

NO2 is partly limited by O3 within the metropolitan area.

O3 may increase when NOx emissions are reduced.

O3, and NO2 are affected by transboundary transport.

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Summary

Following future directions toward improving air quality in Tokyo metropolitan area were implied ;

• Additional regulations on new vehicles may not be effective. High-emitters running in the real-world should be eliminated.

• Reduction of NOx emissions may cause increase of O3. Overall strategies including NMVOC are necessary.

• Most of SPM emission would be consisted of road dust and sources except for vehicles.

• Strategies on the transboundary transport are necessary from the viewpoint of urban NO2 as well as O3 and PM.

Developed JCAP II system is feasible for various analyses.

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Acknowledgement

This study was done in Japan Clean Air Program (JCAP) II.

JCAP II was conducted by Japan Petroleum Energy Center

and supported by the Ministry of Economy, Trade and

Industry, Japan.