Modeling and Assessment of Air

Pollutants Emission from Vehicular

Sources in Tehran

Mohammad Arhami

Acknowledgement

• Mohammad H. Askariyeh

• Maryam Delavarrafiee

• Mohammad Nayebyazdi

• Mohammadreza Momeni

• Reza Salimian

• Dr Khosro Ashrafi

Background

• Air Pollution in Tehran

• Significance of Vehicular Sources

• Importance of Modeling & Assessing Emission

• Necessity of Modeling the Effects of Prospective Policies

Objectives

▫ Developing road link-based emissions estimation model for LDV’s

▫ Estimating emission reductions from prospective policies

▫ Assessing effect of different factors on road link-based emission

▫ Mapping road links’ emission

▫ Modeling the effects on pollutants concentration

Scope

▫ Tehran’s Network of More Than 12000 Links

▫ Different Links’ Characteristics Such as Speed

▫ Meteorological conditions

▫ LDVs of 2010 Tehran’s road network

▫ Pollutants of concerns: CO, HC and NOx

• Implemented Estimation Approaches

▫ Top-Down

▫ Bottom-Up

Road Link-based Emission Model

Network General Information:· Average Speed in Network

· Total Traveled Distance

Link-based Information:· Link Speed

· Link Volume

· Link Length

Vehicular Emission Estimation in a Specific Network

Bottom-Up ApproachE= ∑(e(v)×L×T)

Top-Down ApproachE=e(v)×Total Distance

Vehicle Emission Function:

E = e (Technology, Speed, Age, Fuel

consumption, Ambient air condition)

Pollutant Emission Model:

· COPERT

GIS Data and Travel Demand Models (EMME 2)

Existing Condition

▫ Tailpipe emission measurements under operating conditions (not available)

▫ Chassis dynamometer tests Existing measurement of sample vehicles Total mass of pollutants in a ECE cycle

▫ Field Measurements Tunnel Studies Roadside Measurements

Alternative Vehicles Policies

▫ Environmental Certifications: Pre-ECE, ECE 15-04, Euro 1 to Euro 4

▫ Enforcement of 2004 Certification Plan

▫ Gasoline, LPG, Diesel and Hybrid LDVs

Prospective Policies

Traffic Management Policies

▫ Speed scenarios:

Increasing the speed in each link up to a limit

Management of traffic jams: speed in low-speed road links > 10 km/hr

▫ Reduction of passenger cars share

▫ Combined Scenario

Prospective Policies

Development of Road Link-based

Emission Model

• COPERT emission functions: ▫ Tehran’s meteorological conditions (Mehrabad Station)

▫ Maximum ±5% difference between emission estimations in extreme and average daily conditions

Meteorological Parameter Minimum Value Average Value Maximum Value

Temperature (̊F) 33 64 98

Pressure (hPa) 993 1011 1028

Humidity (%) 15 35 80

Development of Road Link-based

Emission Model

• Use of GIS maps in vehicular emission estimation

Comparison of the Emission Standards

to Measurements

• Chassis Dynamometer Test

Emission Standard CO (gr/km) HC+NOx

(gr/km)

Pre-ECE 44.41 5.53

ECE 15-02 29.07 4.65

ECE 15-04 18.15 4.03

Certification Plan 15.74 2.09

Euro 1 3.09 0.69

Euro 2 1.1 0.36

Euro 3 0.49 0.11

Euro 4 0.16 0.09

Test W. Avg. 43.26 5.57

Tunnel EF Study

13

Parameters Average

Average Wind

Velocity (m/s)

South

Tunnel 3.62

North

Tunnel 3.51

Average

Temp

(C°)

South

Tunnel 33.17

North

Tunnel 33.7

Tunnel Length

(m) 850

Tunnel Cross

Section Area

(m2 )

101.9

Assessment of EF Using Floating Car Method and CO Gas

Tunnel Measurements Results

0

5

10

15

20

25

30

35

40

45

1 8 15 22

29

36

43

50 57

64 71

78

85

92

99

106

113

120

127

134

141

148

155

162

169

176

183

190

197

20

42

112

182

25

23

22

39

24

62

53

Min

Max

Average

Tunnel

CO

pp

m)

)

Roadside

Measurements

0 100 200 300 400

0

1

2

3

4

5

Y = 0.51 + 4.28exp( -0.04x)

Rsqr = 0.99

Y = 0.64+3.75exp( -0.02x)

Rsqr = 0.99

Caline4 data

Observation data

CO

Co

nce

ntr

ati

on

(P

PM

) H

igh

Ter

aff

ic

Distance (m) 0 100 200 300

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Y = 0.53 + 3.87exp( -0.08x)

Rsqr = 0.99

Y = 0.058+3.1exp( -0.02x)

Rsqr = 0.99

Caline4 data

Observation data

CO

Co

nce

ntr

ati

on

(P

PM

) L

ow

Ter

aff

ic

Distance (m)

16

Estimation of EF

Heavy Traffic Light Traffic

Pre-ECE (gr/mile) 42<EF<47 34<EF<37

ECE 15-01 (gr/mile) EF~28 EF~23

ECE 15-02 (gr/mile) 24<EF<28 18<EF<20

ECE 15-03 (gr/mile) 25<EF<30 17.5<EF<19.5

ECE 15-04 (gr/mile) 13.5<EF<16.5 9.5<EF<11.5

Euro 1 (gr/mile) 2.5<EF<3 2<EF<2.5

13.5<EF<16.5 9.5<EF<11.5

EF Traffic Cond

9.52 - 12.61 Heavy traffic

8.03 - 11.42 Light Traffic

• Tunnel

• Roadside

Road Link-based Emission Model

Alternative Vehicles • Total link-based emissions estimated thorough bottom-up and top-down

approaches assuming enforcement of various emission standards for the studied network

0

100000

200000

300000

400000

500000

600000

700000

800000

900000

CO

Em

iss

ion

(to

n/y

r)

• Total link-based emissions estimated thorough bottom-up and top-down approaches assuming enforcement of various emission standards for the studied network

0

10000

20000

30000

40000

50000

60000

70000

80000

HC

Em

iss

ion

(to

n/y

r)

Road Link-based Emission Model

Alternative Vehicles

• Total link-based emissions estimated thorough bottom-up and top-down approaches assuming enforcement of various emission standards for the studied network

0

10000

20000

30000

40000

50000

60000

No

x E

mis

sio

n (

ton

/yr

)

Road Link-based Emission Model

Alternative Vehicles

Effect of Speeds on Alternative Vehicles

Total Network's CO Emission (ton/year)

1000

10000

100000

1000000

0.9 1 1.1 1.2 1.3 1.4 1.5 1.6

Total Network's HC Emission (ton/year)

10

100

1000

10000

100000

0.9 1 1.1 1.2 1.3 1.4 1.5 1.6

Multiplication of Average speed

Effect of Speeds on Alternative Vehicles

Total Network's NOx Emission (ton/year)

R² = 0.9246

100

1000

10000

100000

0.9 1 1.1 1.2 1.3 1.4 1.5 1.6

Effect of Speeds on Alternative Vehicles

Alternative New Vehicles

Fuel Type CO HC NOx

Gasoline Euro 4 1 1 1

Diesel Euro 4 0.32 0.46 14.2

LPG Euro 4 5.29 1.05 0.9

Hybrid 0.22 0.1 0.08

Traffic Management Policies (Speeds)

Pollutant

Strategy

Emission Standards

Certification plan

enforcement Pre-ECE

Emission Reduction

(%)

Emission Reduction

(%)

CO

Present condition 0 0

10% speed increase 6% 6%

20% speed increase 10% 11%

All speeds > 10 km/hr 5% 5%

HC

Present condition 0 0

10% speed increase 6% 6%

20% speed increase 12% 12%

All speeds > 10 km/hr 6% 6%

NOx

Present condition 0 0

10% speed increase -1% -1%

20% speed increase -1% -2%

All speeds > 10 km/hr 0 0

CO - Pre-ECE

CO (kg/km)

Map of Emission

CO - enforcement of certification plan

CO (kg/km)

Map of Emission

CO (kg/km)

CO - combined scenario

Map of Emission

Pre-ECE Scenario

CO (µgr/m3)

Modeling concentration

Enforcement of Certification Plan Scenario

CO (µgr/m3)

Pre-ECE Scenario

NOx (µgr/m3)

Enforcement of Certification Plan Scenario

NOx (µgr/m3)

Thank You!