Table 1. National and Seoul Air Quality Standards

With respect to the atmospheric environment of the capital area, the concentration of fine dust, which causes lung cancer and premature death, reaches twice that of Tokyo. The social costs due to air pollution amounts to an annual 12 trillion won, and the number of annual premature deaths caused by fine dust is estimated to reach 20,000 in 2024. As fine dust, which, as said earlier, is harmful to the human body, is mainly generated from diesel vehicles, measures to reduce the fine-dust levels in the air in Seoul targeting diesel vehicles are needed, and therefore, fine-dust reduction measures targeting diesel vehicles have been promoted in the air quality management areas such as Seoul, Gyeonggi, and Incheon, based on the Special Act on Seoul Metropolitan Air Quality Improvement.

According to OECD in 2002, the level of fine-dust (PM10) pollution in Seoul was the worst among the large cities of the OECD countries. To host the 2002 World Cup events in a more pleasant environment, the South Korean government actively promoted policies and researches on the spread of no- or low-pollution vehicles. The Seoul metropolitan government proceeded with projects involving replacing diesel buses with CNG buses and turning mid-sized and large old diesel vehicles into low-pollution ones. The project of attaching an emission reduction device to diesel vehicles is included in the project of turning old diesel vehicles into low-pollution ones.

Meanwhile, Seoul’s PM10 and NO2 concentrations in 2003 were 69 ㎍/m3 and 38 ppb, respectively, 1.9-3.6 and 1.4-1.9 times those of the major OECD cities. The social cost of the capital area due to the damages caused by such air pollution was estimated at 10 trillion won in 2000, and the number of deaths in Seoul caused by fine dust was estimated to have been 1,940 in the same year. To reduce the high fine-dust concentration in the city’s air, the Seoul metropolitan government established the Seoul Metropolitan Air Quality Control Master Plan, which includes various improvement measures, among them the introduction of Total Industrial Site Volume Control System(TISVCS) by the end of 2003, the spread of low-pollution vehicles, and the management of exhaust gas from vehicle.

Some years before 1995, the number of registered vehicles in Seoul showed a more than  10% rising trend annually due to the rapid industrialization and income increase, but the growth rate slowed down from 1995. The total number of vehicles in South Korea in 1965 was only about 40,000, but the number went beyond 10 million in 1997, increasing more than 250 times in 30 years. As of 2014, the total number of vehicles in the city is 201.2 million, and the air pollution problem caused by exhaust gases is becoming increasingly serious. In particular, 8.96 million vehicles, about 44.5% of the total number of vehicles in South Korea, are concentrated in the capital area (Seoul･Gyeeonggi･Incheon). Particularly, 15% of the vehicles are concentrated in Seoul, which also has a very high population density. Thus, air pollution caused by vehicle pollutants has become a very important issue in large cities.

Table SEQ 표 \* ARABIC2. Increase in the number of vehicles in the entire country and in Seoul

At the end of 2014, the diesel vehicles in Seoul accounted for 33.1% of all the vehicles in the city, relatively higher than in other countries. The reason for this was that diesel oil is cheaper than gasoline oil due to the country’s industrial and energy policy, and the fuel efficiency of diesel vehicles is slightly superior. In other countries, such as the United States, Japan, and Germany, the diesel vehicles account for only 3, 13, and 18% of all the vehicles, respectively. With the improvement of the engine and emission control technologies, however, the supply of diesel vehicles has increased due to their economic benefits.

Table SEQ 표 \* ARABIC3.  Number of registered vehicles by type

In 2011, the air pollution emissions from vehicles totaled 135,637 tons, which accounted for 52% of the total emissions, and 81% of the CO emissions, 45% of the nitrogen oxide (NOx) emissions, and 49% of the fine-dust emissions are generated from vehicles.

Figure 1.  Pollutant emissions from vehicles

『The 1st Special Measures for Seoul Metropolitan Air Quality』seeks to secure the degree of visibility of the open sea of Incheon from Namsan on a clear day. Towards this end, an about 4 trillion won budget from both the national treasury and the local funds had been used for 10 years (2005-2014). Ninety percent of the total budget was allotted for the old-diesel-vehicle exhaust gas reduction project, and an action plan was formulated and implemented to turn old diesel vehicles into low-pollution ones. The improvement target was set to 40㎍/m3 PM10 (Tokyo) and 22ppb NO2 (Paris).

『The 2nd Special Measures for Seoul Metropolitan Air Quality』 seeks to realize a healthy 100-year-old era with clean air, and efforts were set to be made to achieve the goal from 2015 to 2024. The improvement targets were set to 20㎍/m3 PM2.5, 30㎍/m3 PM10, 21ppb NO2, and 60ppb O2, and the focus was expanded to include gasoline and gas cars, in addition to diesel vehicles.

In the case of specific diesel vehicles, cars whose emission warranty period has expired in accordance with Article 46 of 『Clean Air Conservation Act』; light cars and passenger cars whose emission warranty period has expired in accordance with No. 3, Annexed Table 5 of 『Enforcement Regulations of Clean Air Conservation Act』; and vehicles whose emission warranty period has expired in accordance with No. 5, Title 4 are excluded from the implementation of 『Clean Air Conservation Act』, as shown below.

Table SEQ 표 \* ARABIC4. Enforcement Regulations of the Clean Air Conservation Act

Annex Table 18 of the Enforcement Regulations of the Clean Air Conservation Act regulates the exhaust gas application period depending on the production period of the diesel vehicles.

Table 5. Enforcement Regulations of the Clean Air Conservation Act

1) Promotion of the pilot project

2) Full-scale implementation

3) Mandatory installation

Table 6. Seoul Air Quality Improvement Targets

As of 2015, the city, through its In-Use Diesel Vehicle Emission Reduction Project, has installed low-emission devices like DPFs in 150,948 diesel vehicles.

According to the Special Act on Seoul Metropolitan Air Quality Improvement and local by-laws, the city made it mandatory starting on January 1, 2008 to install low-emission devices in over-7-year-old diesel vehicles weighing over 2.5 tons whose low-emission guarantee period (2 years for vehicles weighing over 3.5 tons, and 5 years for vehicles weighing under 3.5 tons) has expired. The government and the city shouldered 83-96.5% of the installation cost. Likewise, the aforementioned devices had to be installed in over-7-year-old diesel vehicles weighing between 2.5 and 3.5 tons starting in January 2009.

In particular, between 2013 and 2014, the city installed PM-NOx simultaneous-reduction devices in 106 large diesel buses as part of the Nitrogen Oxide (ultra-fine-dust inducer) Reduction Demonstration Project. After analyzing the results of the demonstration project, the city started expanding the project implementation.
 
Although the long-term effectiveness of the Diesel Vehicle Emission Reduction Device Installation Project has yet to be evaluated, it can be said that the air quality in Seoul has been improving based on the data obtained so far, such as a decrease in the number of days with 100㎍/m3 or more ultra-fine dust in the air and an increase in the number of days with no more than 30㎍/m3 ultra-fine dust. Moreover, the number of high-emission-vehicle reports, which indicates the citizens’ perception of the air pollution level in the city, has dramatically decreased.
The Diesel Vehicle Emission Reduction Device Installation Project was planned to be implemented from 2005 to 2024 for improving the air quality in the capital area. Since 2009, it has so far been implemented in five other metropolitan cities: Busan, Daejeon, Daegu, Gwangju, and Ulsan.
 
It is very important to make sure that the installed emission reduction devices are working as intended. Recognizing the importance of the inspection of such devices, the city has encouraged the manufacturers to inspect the devices regularly and set up the city’s own inspection team. The team has been examining the vehicles with an installed emission reduction device, and has been issuing device improvement or disposal orders to the people whose vehicles failed in the inspection.

The owners of the vehicles with an installed emission reduction device can receive free after-sale (A/S) services during the 3-year warranty period (3 years or 160,000 km for DPF, 3 years or 80,000 km for DOC or for the LPG remodels). Also, the owners of vehicles with a class 1 emission reduction device can receive free filter cleaning per year at more than 40 cleaning centers in the capital area.

According to the Special Act on Seoul Metropolitan Air Quality Improvement, vehicles with an installed emission reduction device should be operated for at least 2 years after the device installation, excepting unavoidable situations like a natural disaster, a fire, or a theft. Moreover, the vehicle owners are required to return the device to the Korea Automobile Environmental Association when they are to dispose of their vehicles.
 
If an owner removes the device without any valid reason before the mandatory operation period, or fails to return it, the owner has to return the subsidy.

To handle the complaints regarding the installed emission reduction devices, the manufacturers of the devices operate their own A/S call centers and cleaning centers. If any dispute between an owner and a manufacturer occurs, the city will act as the arbiter.

The primary reason that DPFs are disqualified on account of their under-performance, and become subject to a removal order, is operating the vehicle under a severe environment falling outside the certification criteria. Other reasons are the lack of post-management by the manufacturer and the vehicle maintenance failure of the vehicle owners. Theoretically, the DPF can reduce the amount of exhaust emission by more than 80%. Therefore, vehicle owners should do their best to maintain the device’s optimal performance level.

Once a vehicle owner removes the device from her or his vehicle, she or he is no longer qualified to receive the corresponding benefits and subsidies. Thus, the car owner is obliged to pay the environment improvement charges and to regularly subject her or his vehicle to an exhaust emission test. Moreover, the manufacturer has to return the subsidy.
 
Realizing the broad characteristics of air pollution, Seoul, Incheon, and Gyeonggi provinces decided to cooperate with one another starting in 2010 to maximize the improvement of their air quality, after collecting various opinions from experts and citizens. The subject vehicles are diesel vehicles weighing over 2.5 tons, that are over 7 years old, and that have not taken any corrective measure within 6 months after receiving Seoul’s emission reduction order or that does not pass the total emission gas test. Any of the three aforementioned local governments can impose a 200,000 KRW fine after a one-month warning period on the owners of vehicles without an emission reduction device found in their respective jurisdictional roads. Moreover, they have set up an unmanned enforcement system using CCTVs on their main roads (e.g., Olympic Expressway), and have tightened the control over the vehicles without emission reduction devices.

• Current status of the installation of the Driving Restriction Monitoring System (operated since March 2012)
- 24 camera installations on 7 different spots on Seoul’s main roads
• Implementation of the Driving Restriction Monitoring System (2014)
- Caught 746 vehicles, issued a warning to 679 vehicles, and imposed a fine on 67 vehicles

Figure 2. Status of vehicle travel restriction system installations

DPF is installed in mid-sized and large diesel vehicles, and can eliminate more than 70% of the exhaust gas by collecting pollutants like PM, depositing them in the catalyst-coated filter, and then converting them to CO2 or vapor. Partial diesel particulate filters (p-DPF) is installed in mid-sized and small diesel vehicles (weighing no more than 3.5 tons), and its catalysts convert pollutants to hazardless materials without a collection process, which relieves p-DPF of any post-management measure. DOC was installed in small diesel vehicles, but its installation has been suspended since 2010 due to its low cost-to-benefit ratio of 10:20% performance in reducing ultra-fine-dust emissions. Since the full-scale implementation of the emission reduction project with focus on the public transit buses and business vehicles in 2005, DPFs have been installed in 89,423 diesel vehicles, and they are expected to be installed in 6,600 vehicles per year until 2019. According to the Special Act on Seoul Metropolitan Air Quality Improvement and local by-laws, the owners of diesel vehicles weighing over 2.5 tons, are over 7 years old, and whose low-emission warranty period (2 years for vehicles weighing at least 3.5 tons; 5 years for vehicles weighing less than 3.5 tons) has expired can obtain subsidies from the government and the city for 90-95% of the implementation cost for any emission reduction measure, such as the installation of an emission reduction device.
 
 

Table 7. Status of DPF devices and  subsidy (amount, effects)

Table 8. Type of diesel emission control devices

1) First-class emission control device (DPF: diesel particulate filter)

Figure 3.  How DPF works?

(Source: Korea Automobile Environmental Association, http://www.aea.or.kr/main_business/technology.php)

Figure 4. DPF regeneration method

(Source: Korea Automobile Environmental Association, http://www.aea.or.kr/main_business/technology.php)

Table  9. Heat supply system by generative method

Figure 5. p-DPF structure

 

Figure 6. How p-DPF  works?

 

3) Third-class emission control device (DOC: diesel oxidation catalyst)

Figure 7. How DOC device controls emission
 

Figure 8. DOC structure

Figure 9.  Reduction of pollutants by emission control devices (2007-2009) (Unit: ton)

Source: Analysis of the air quality improvement effects of pollution control measures (2011)

Table 10. Average exhaust gas reduction ratio through the implementation of the NO_x reduction pilot project