Air Pollution Control Plan for In-Use Vehicles in the
Southern Taiwan Air Basin
Control #: 1126
Jiun-Horng Tsai, Yung-Chen Yao, Hui-Fen Ye
Department of Environmental Engineering, National Cheng-Kung University, Tainan, Taiwan
(E-mail: jhtsai@mail.ncku.edu.tw)
Hung-Long Chang
Department of Environmental Engineering, Fu-Yin University, Kaohsiang, Taiwan
ABSTRACT
Emissions from motor vehicles contribute a significant portion in the overall emission
inventory. To tackle such problem, the Taiwan Environmental Protection Agency has tried
to develop a comprehensive strategy to reduce emission from mobile sources. In-use
vehicles contribute a significant portion of emissions in the overall inventory. Therefore
several strategies have been developed. For instance, the adoption of more stringent
emission standards. According to emission inventory in 2000, there were approximate 2.3
millions motorcycles, eight hundred thousands gasoline vehicles, and 33 thousands diesel
trucks in the Southern Taiwan Air Basin, which contributed approximate 22% of
non-methane hydrocarbon (NMHC), 28% of nitrogen oxides (NOX), and 74% of carbon
monoxide (CO).
This paper discusses the potential control plan for in-use gasoline vehicles in 2007. In use
gasoline vehicle consists of private passenger car, business passenger car, and gasoline truck.
Control strategies for all types of vehicle have been evaluated based on technical feasibility,
emission reduction potential, and the cost effectiveness. Control strategies are base on the
regulations and authority of EPA. For in-use gasoline vehicles, four measures has been
developed, the major control strategies are including enhanced the inspection/maintain (I/M)
program, enhanced the management and elimination of polluted vehicle, maintain the
performance of pollution control device and the management of the import in-use vehicle.
The highest projected equivalent emission reduction for CO, HC, and NOx from the previous
pollution control measures is approximate 2,172 ton/yr in 2007. The control plan shows a
significant progress to reduce the exhaust emissions from in-use gasoline vehicles from the
Southern Taiwan Air Basin.
INTRODUCTION
The area of the southern Taiwan air basin (Kao-Ping air basin) is approximate six thousands
kilometer square. Two-thirds of the area is hilly terrain.
This air basin has been classified
as a non-attainment region of ozone and PM10 since 1990’s. In 2002, there were
approximate 8% of air monitoring data classified as “poor” or “unhealthy”, with the pollutant
standard index (PSI) higher than 100 in the Kao-Ping air basin [TEPA, 2000].
There were approximate three millions of residence and over 3.4 millions of vehicles (0.9
million gasoline vehicles, 2.5 million motorcycles and 72 thousands diesel engine) in the air
basin in year 2004. Amount of vehicles has increase about 51% by compare with 10 years
ago. Several studies [TEPA, 2000; Tsai etc., 2000; Chan etc., 2001] indicate that the
on-road mobile sources are one of the dominant contributors which caused the serious air
pollution issue in Taiwan.
Taiwan Environmental Protection Administration (TEPA) proposed a control plan for air
pollution in late 1990’s and has been conducting a series of control measures to reduce
emissions from mobile sources and stationary sources simultaneously [TEPA, 2000]. Since
motor vehicle density in Taiwan is higher than other country. In order to control the growth
of pollution associated with motor vehicles in major urban downtown, the TEPA has
developed a comprehensive strategy in mobile source. For in-use motor vehicle, there are
several strategies have developed, such as stringent emission standards, emission control
technologies, but also have some deficiencies. Abatement of mobile source emission is an
important task in the control program for attainment demonstration, especially in in-use
vehicles.
The emission inventory (TEDS, 2000) of air pollutants shows that 74% of CO, 28% of NOx,
and 22% of NMHC in Taiwan is contributed by on-road mobile sources [TEPA, 2001]. The
car age distribution results indicated over 50% vehicles are over 5 years old. High aged
gasoline that aged over 7 years was taken over 50%. Air pollutants emitted from aged
on-road vehicles are significant question in Taiwan. This paper discusses the near-term
control measures for in-used gasoline vehicles emissions in the air basin, includes passenger
car, taxis and low-duty gasoline trucks.
METHODOLOGY
Development of Control Plan
TEPA organized a task force to develop the air pollution control plan of the Kao-Ping air
basin in late 1990’s. The experience of air quality management plan (AQMP) developed by
the south coast air quality management district (SCAQMD) in California had being learned
by the government and had being applied in the development of the control plan in Taiwan.
The process for developing the control plan of mobile sources includes the emission
estimation, control measure development, emission abatement estimation, and
cost-effectiveness analysis [TEPA, 2000].
Development of Control Measure
Development of control measure is considered for in-use gasoline motor vehicles.
Meanwhile both regulatory approach and incentive program are included. However,
technical limitation and administration feasibility are also considered. Consideration factors
are emission abatement potential, technical feasibility, administration feasibility, and
cost-effectiveness for each candidate measure.
Fig.1 shows the control measure
development process.
Fig.1 The development process for gasoline vehicle emission control measure
Emissions Estimation for In-use Gasoline
Vehicle
Subcategory Emission Analysis
－Number of influenced vehicle
－Vehicle kilometer traveled (VKT)
－Engine type
－Deterioration Rate (DR)
Candidate Control Measure Development
(New and In-use vehicles)
Assessment of Candidate Measure
。Emission Abatement Potential
。Technical Feasibility
。Administration Feasibility
。Cost-effectiveness
Emission Abatement Estimation
Emission abatement for each control measure was estimated by the followings:
EAP = NV × VKT × △EF × 10-6
EAP : Emission abatement potential (tpy)
NV : Number of vehicle which were influenced by the proposed control measure
VKT : annual travel distance of vehicle (km/yr)
△EF : improvement of emission factor (g/km)
Due to the effect of multiple pollutants abatement as a control measure has been adopted, the
equivalent emission abatement (EEA) was applied as the parameter for assessing the
effectiveness of each control measure. It was defined as the summation of hydrocarbon
(HC), oxides of nitrogen (NOx) and 1/7 carbon monoxide (CO) [SCAQMD, 1997]. Only a
few of NOx, SOx and PM emission are caused by gasoline engine exhaust, therefore
abatement of those compounds is neglected in this study.
RESULTS AND DISCUSSION
Candidate Control Measures
Emission abatement from in-use motor vehicle is necessary and is expected effectively. There
are three types of gasoline vehicle (passenger car, taxis and low-duty gasoline trucks) are
included in this project. Control strategies are base on the regulations and authority of
TEPA. We establish some measure frameworks for all types’ vehicles, all candidate control
measures were follow those criterions. The measure frameworks are as follow:
 Encourage older, higher-emitting vehicles retirement
 Ensure effective of air pollution control devices for in-use motor vehicles
 Enhanced the inspection/maintain (I/M) program
 Manage the import gasoline and diesel vehicles
Table 1 list registered vehicles numbers and VKT of all motor vehicles in Kao-Ping Area.
There were almost 2.4 millions in-use motorcycles in the Kao-Ping air basin in 2003. For
gasoline vehicles, number of vehicle was taken 26% but the contribution of air pollutant was
higher then other vehicles. The major emission air pollutants were CO and NMHC. Table 2
shows the emission contribution of CO, NMHC, NOx and PM from on-road vehicles.
Table 1. The vehicles numbers and VKT values for motor vehicles in Kao-Ping Area
Type
Motorcycle
Gasoline Vehicle
Diesel Engine
Number (car)
VKT (km/yr)
Two-stoke engine motorcycle (MC-2)
1,015,967
3,400
Four-stoke engine motorcycle (MC-4)
1,488,619
4,300
791,060
17,800
Taxis
10,721
58,600
Light-duty gasoline trucks (LDGT)
79,695
19,900
Light -duty diesel trucks (LDDT)
37,504
20,700
Heavy-duty diesel trucks (HDDT)
34,204
51,070
Passenger vehicles (PV)
Table 2. The percentage of on-road vehicles for air pollutant emission in Kao-Ping Area
Unit: percentile (%)
Type
Number
CO
NMHC
NOx
PM10
Gasoline vehicle
26
63
39
28
23
Motorcycle
72
28
52
9
14
Diesel engine vehicle
2
9
8
63
64
There were total 4 control measures proposed for the in-use gasoline vehicles, each measure
was evaluated emission abatement and cost effectiveness in the study. These candidate
measures were included the followings:
(1) Enhancement of smoke-check (I/M) program
(2) Incentive program for scrapping old (high-aged) vehicles
(3) Enhancement on-road inspection by RSD
(4) Reporting dirtiest vehicles (smoking vehicle)
(5) Manage the import gasoline vehicles
C1: Enhancement of Smoke-check Program
Taiwan conducts the smoke-check program (or inspection and maintenance program, I/M) in
vehicle inspection program for passage car, taxi and light duty gasoline truck. All gasoline
vehicles that age is over 5 years must be smoke-checked. Beside smoke-check, safety
inspection is also including in vehicle inspection program. But the inspection authority is
belonging to Division of Motor Vehicles, Directorate General of Highways. There are two
kinds of inspection agency, one is public and the other is private station. The result of failed
percentage indicated vehicle that inspect in private inspection station has lower failed
percentage. The effect of emission reduction is not good enough. On the other hand,
TEPA has conducted motorcycle smoke-check program under Air Pollution Prevention Act,
and obtain great emission reduction. Therefore this strategy is designed as motorcycle
smoke-check system, in-use gasoline vehicles smoke-check part is taking over by
environmental agency. There are two control measures developed:
(1) Case A: Vehicles are classified according to age, older vehicles (over 10 years) have more
severe require than low aged vehicle (5~10 years). Older vehicles have to do
smoke-check in public inspection station, the cars’ age between 5 to 10 years can chose
public or private station.
(2) Case B: Combine Case A with cut down the inspection age from 5 years to 3 years, to
estimated emission abatement.
The gross emission abatement of Case A control measure is 506 (CO), 69 (THC) and 33
(NOx) tons per year (ton/year) in Kao-Ping area. The equivalent emission abatement is
approximate 182 tons per year. For Case B, the gross emission abatement is 651 (CO), 80
(THC) and 39 (NOx) tons per year (ton/year) in same area. The equivalent emission
abatement is approximate 212 tons per year. The cost-effectiveness for Case A and Case B
were approximate 42 thousand USD /ton and 19 thousand USD /ton, respectively.
C2: Incentive program for scrapping old (high-aged) gasoline vehicles
Taiwan EPA has adopted emission standard for on-road vehicles in four phases since 1987.
In-use gasoline vehicles compliance with the phase I standard is taken 14% (660 thousands
cars) in 1998. The emission factor of CO, HC and NOx will increase in accordance with car
age, 10 years old vehicles which emit about 20 times of CO and HC, 10 times of NOx than a
new car (less than 1 year). But the VKT is 40% less than a new car. Table 3 indicates the
annual emission and VKT in different passenger car age. This control measure was
designed by three cases to retire high-aged cars:
(1)Case A: pay full subvention for over 10 year’s vehicles and not meet recently
smoke-checked to motivate high emitted cars retired, the other old vehicles ( over 10
year’s but meet emission standard) is giving 50% subvention.
(2)Case B: pay full subvention for over 10 year’s vehicles and not meet recently
smoke-checked only, the over 10 year’s but meet emission standard is not subsidized.
(3)Case C: pay full subvention for all over 10 year’s vehicles.
The gross emission abatement of Case A control measure is about 4380 (CO), 584 (THC) and
493 (NOx) tons per year (ton/year) in Kao-Ping area. The equivalent emission abatement is
approximate 1702 tons per year. For Case B, the gross emission abatement is 1163 (CO),
158 (THC) and 112 (NOx) tons per year (ton/year). The equivalent emission abatement is
approximate 436 tons per year. The gross emission abatement is 4470 (CO), 600 (THC) and
478 (NOx) tons per year (ton/year) in Case C. The equivalent emission abatement is
approximate 1717 tons per year. The cost-effectiveness for Case A, Case B and Case C is
970 USD /ton, 3,800 USD /ton and 3,850 USD /ton, respectively.
emission abatement and most cost-effective in this measure.
Case A has highest
Table 3. The Annual Emission and VKT of Different Passenger Car Age (Base year: 2000)
Age
(year)
CO emission
(kg/year)
HC emission
(kg/year)
NOx emission
(kg/year)
VKT*
(103km/year)
CUM*
(103km)
1
2
3
4
5
18.4
17.3
13.3
12.4
11.3
1.6
1.6
1.5
1.5
1.3
2.7
2.6
2.9
2.7
2.5
16.13
14.45
12.95
11.60
10.39
16.13
30.58
43.53
55.13
65.52
6
7
8
9
10
10.4
20.7
72.6
108.5
139.3
1.3
2.2
6.4
9.0
11.0
2.3
3.0
6.4
8.5
10.0
9.31
8.34
7.47
6.69
5.99
74.83
83.17
90.64
97.33
103.33
* VKT : Vehicle Kilometer Traveled, CUM : Cumulative Travel Kilometer
C3: Enhancement on-road inspection by RSD
Since remote sensing (RSD) systems to the measurement of vehicle emissions is not new.
Taiwan EPA has adopted RSD system to screening high emitted gasoline vehicles that are
highly likely to need of repair in 1996. However, only approximate 3.5-15% of these
high-aged vehicles were identifying by RSD, because screening standard are focus on Phase I
emission standard for in-use vehicles, it is too lenient. This control measure was designed
to increase rate of screen, and require RSD failed vehicles to do I/M test. The failed vehicle
must repair failure part to eligible. The measure was assumed 70% screening rate of all
passenger car, failed percentage were12% for RSD and 40% for I/M test. It’s estimated that
may reduce approximate 710, 88 and 46 ton/year for CO, THC and NOx, respectively. The
equivalent emission abatement is approximate 235 tons per year. The cost-effectiveness of
this measure is between 7,400 USD/ton.
C4: Reporting dirtiest vehicle (smoking vehicle)
A well maintained vehicle is a cleaner running, lower emitting vehicle. A few smoking
vehicles can have a very significant effect on our air quality. The dirtiest vehicles were
found on contribute about 49 percent of total automotive pollution in Southern Taiwan.
Thought reporting smoking vehicle hotline will warning the owner of smoking vehicle to
repair it. This control measure was designed to promote report way, and require smoking
vehicles to do I/M test. If it failed the test then will have a penalty first, then the failed
vehicle must repair failure part to eligible. The measure was assumed 8% on road gasoline
vehicles is reported and the failed percentage is 49%for I/M test. It’s estimated that may
reduce approximate 21, 2.5 and 1.2 ton/year for CO, THC and NOx, respectively. The
equivalent emission abatement is approximate 6.8 tons per year.
The cost-effectiveness of
this measure is 110 thousands USD/ton.
C5: Manage the import gasoline vehicles
Taiwan opened the country up to the import vehicles since year 2001. The number of
import in-use gasoline vehicle is about 1000 cars per year. TEPA has established a rule to
prevent air pollutant emission from those import vehicles in 2003. The rule calls “Air
Pollution Emission Certification Rule for Import Vehicles”. Only the import vehicles meet
exhaust emission standard in new vehicle level can importable. TEPA has already to check
on import vehicles when they are just arrival. This measure is assumed if TEPA does not do
any prevention measure in import vehicles, to estimate how much pollution will be emitted.
It’s estimated that may reduce approximate 3.1, 0.4 and 0.2 ton/year for CO, THC and NOx,
respectively. The equivalent emission abatement is approximate 1.0 tons per year. Since
the number of import vehicle was not much, therefore the EEA was little, but if government
does not have any measure, when the number is increase it will cause more pollutants
emitted.
Table 4 shows the emission abatement estimation of these four measures.
Table 4. Air pollutant emission abatement estimation of gasoline vehicles various control measure
Emission Abatement (ton/yr) Cost effectiveness
CO
HC NOx EAP (103 USD/ton)
Control Measure
C1
Case A:
of Older vehicles have to do smoke-check in public station
560
69
33
182
42
651
80
39
212
19
584
493
1702
0.97
158
112
436
3.8
4470
600
478
1717
3.9
C3 Enhancement on-road inspection by RSD
710
88
46
235
7.4
C4 Reporting smoking vehicle
21
2.5
1.2
6.8
110
C5 Manage the import gasoline vehicles
3.1
0.4
0.2
1.0
---
Enhancement
smoke-check program Case B:
Combine Case A with cut down inspection age to 3 yrs.
C2
Case A:
Subvention divided to 100% and 50% for not meet 4379
Incentive program for smoke-checked 10 yrs vehicles and the other old vehicles.
scrapping
high-aged Case B:
1163
vehicles
Only not meet smoke-checked 10 yrs vehicles have subvention
Case C:
pay full subvention for all over 10 year’s vehicles
CONCLUSION
Mobile sources are the important emission sources which cause the air pollution issue in
southern Taiwan since 1990’s. Emissions from the great number of gasoline vehicles in
Kao-Ping air basin should be abated with high priority. Taiwan EPA cooperated with local
environment protection agency to conduct a series of control measures in order to reduce the
emissions from on-road mobile source, especially in passenger and motorcycle. The control
measures have been conducting since late 1990’s and show an evident progress. However,
incentive program for scrapping high-aged vehicles and enhancement of roadside inspection
have shown the significant abatement of air pollutant emissions from in-use gasoline vehicles.
The measure of case C of scrap old passenger car presents significant reduction potential
(1,717 ton/year), and the cost-effectiveness is not high. The measure of case A of scrap old
passenger car has high potential of emission reduction also, 1,700 ton/year, and the
cost-effectiveness is much lower than other measures. The control plan shows a significant
progress to reduce air pollution emissions from in-use gasoline vehicles in the air basin.
More effective measures for gasoline vehicles and emission abatement should be proposed
for further emission reduction in the air basin.
ACKNOWLEDGEMENTS
This research was supported by the National Science Council and the Taiwan Environmental
Protection Administration through grant NSC 93-EPA-Z-006-002.
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KEYWORDS
In-use gasoline vehicles, air pollutant, emission control measure, Southern Taiwan