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!