April 12, 2011


Tokyo Metropolitan Government's Efforts to Control Diesel Vehicle Emissions

Keywords: Newsletter 

JFS Newsletter No.103 (March 2011)
"Initiatives and Achievements of Local Governments in Japan" (No. 34)

The Tokyo Metropolitan Government (TMG) governs the capital of Japan, and plays a leading role in the field of Japanese environmental policy. Its diesel vehicle emission controls are the focus of this article.

Diesel Vehicle Emissions in Tokyo - Background

In 1968, the Japanese government enacted the Air Pollution Control Law to regulate emissions from cars as well as from factories. This law resulted in reductions in smoke and soot, including nitrogen oxides (NOx) and suspended particulate matter (SPM) emitted from gasoline-fueled vehicles. In recent years, the government has also been tackling control measures for Particulate Matter 2.5 (PM 2.5), much finer particles than SPM. Since the automobile industry is one of the biggest industries underpinning the Japanese economy, many technical improvements have been made proactively to tackle the exhaust emission issue.

Compared to gasoline engines, diesel engines generally employ a higher compression ratio, and are more fuel-efficient due to lean combustion. This is why diesel engines have been used mainly for long-haul trucks. Diesel engines, however, have downsides too. For example, because of the combustion system, they create many emissions such as NOx and black carbon (soot). Also, in terms of emission control and technical improvement, diesel vehicles have tended to fall behind gasoline vehicles.

Tokyo is a city of heavy traffic, with several major arterial highways including the Metropolitan Expressway. According to the Road Traffic Census for fiscal 1999, average daily traffic volumes were 140,000 cars on Route 14, which goes to Chiba Prefecture next to Tokyo, 120,000 on the Inner Circular Route, and 120,000 on the Bayshore Route. Much of the traffic is long-haul, heavy-duty trucks transporting cargo.

TMG at that time was naturally aware of the advantages of diesel vehicles compared to gasoline vehicles such as higher fuel efficiency, lower CO2 emissions and higher durability. On the other hand, highly-populated Tokyo with a high density of industries suffered from air pollution -- SPM concentration around Tokyo, particularly along major streets, did not meet environmental standards, which set the upper limit of pollutants that should be maintained in order to protect residents' health.

SPM concentration levels in the Kanto Region were higher particularly in and around the Tokyo metropolitan area. Research to identify emission sources of particle matter (PM) found that most of the vehicle-derived PM was from diesel vehicles, which consisted of only 20 percent of all traffic. And, although PM is regarded as a carcinogen and a cause of respiratory problems, the Japanese national government set emission standards for PM surprisingly late, in 1994. Even in Tokyo, as of 1999 when Shintaro Ishihara was elected as a governor of Tokyo, TMG's own emission standard for PM was much looser than standards in Europe and the United States.

Against this backdrop, TMG decided to tackle controlling diesel vehicle emissions far ahead of the national government.

History of TMG's Diesel Emission Regulations

In August 1999, TMG proposed the "Say No to Diesel Vehicles" campaign. It consisted of five proposals such as 1) Don't drive, buy, or sell diesel vehicles in Tokyo, 2) Require substitution by gasoline vehicles of diesel-fueled cars for commercial use when there are possible alternatives, and 3) Encourage development of exhaust emission purification technology and require installation of such systems in diesel vehicles. Others included a fairly groundbreaking proposal to reform tax breaks that make diesel cheaper than gasoline.

Based on these proposals, TMG made plans and started regulating diesel vehicles. In December 2000, it enacted the Tokyo Metropolitan Environmental Security Ordinance and started a campaign to eliminate non-compliant diesel vehicles by September 2002. Later, in October 2003, TMG started diesel vehicle control in earnest. This stimulated three neighboring prefectures to introduce similar ordinances and implement regulations at the same time.

Controls under these ordinances are strict enough to ban diesel vehicles (except passenger vehicles) which do not meet PM emission standards throughout Tokyo (except on the small offshore islands that fall under TMG's jurisdiction). This initiative has two noteworthy features: it was planned, established and implemented to reach a clear goal in order to prevent health problems of people around Tokyo, instead of starting from feasibility, and it applies to all diesel vehicles running in Tokyo.

Also, the process from planning to enforcement was conducted remarkably quickly, taking only four years from the first proposals in August 1999 to implementation. The regulations helped reduce SPM concentrations so that they met environmental standards in fiscal 2005, and remained below the designated level for 4 more consecutive years, till 2009. As for NO2 concentrations, only 30 percent of air pollution monitoring stations met environmental standards before implementation, but 50 percent did in 2005, and 90 percent did in 2009.

Promoting Diesel Emission Regulations

These considerable outcomes were achieved by overcoming various obstacles to implementing these regulations. Exhaust gas restrictions higher than national emission standards were considered systematically difficult because the target vehicles are migrating emitters.

Restricting traveling vehicles was also difficult. The TMG ban on driving diesel vehicles in Tokyo required non-compliant vehicle owners to install exhaust gas purifiers. When no improvements were forthcoming, TMG banned non-compliant business owners from operating in the Tokyo area. With a further violation, TMG imposed a penalty of JPY500,000 (US$6,170) or less and public disclosure of the names of violating business owners and shippers. TMG has issued about 460 bans on transport business operations in the Tokyo area, but there have been no penalty cases yet.

Violators were detected with high-quality monitoring cameras at certain points because many of the targeted diesel vehicles are trucks and buses that repeatedly take the same routes. Such vehicles were identified through their license plate car registration, and vehicle pollution inspectors delivered administrative directions to the vehicle owners.

To improve the technical aspects of the regulation system, TMG introduced continuous regeneration diesel particulate filters (DPFs) which were known to only some experts, and appealed to the Petroleum Association of Japan to prioritize the realization of a low sulfur diesel fuel supply, essential for purifying exhaust gases. Nationwide supplies were made available by 2003.

More difficult was how to deal with vehicles coming in from other prefectures. To solve this problem, TMG encouraged neighboring Chiba, Saitama, and Kanagawa Prefectures to establish similar clean-diesel ordinances. TMG played a central role in networking the regulation of diesel vehicles and preventing air pollution in Tokyo and these three surrounding prefectures.

One of the initiatives was to deliver stickers to owners of vehicles compliant with regulations; this was undertaken jointly by eight major prefectures and cities in Greater Tokyo Area. TMG also introduced a subsidy for small and medium businesses to provide half of their necessary costs for replacing vehicles and installing purifying devices. It also requested not only its neighboring prefectures, but local governments all over Japan as well as relevant trade associations to implement this support system.

Challenging public beliefs

A dramatic promotion and public relations campaign was one of the TMG's efforts for regulating diesel vehicles. These included onsite guidance to the approx. 3,800 businesses in the area that owned 20 or more vehicles; sending more than a total of 5.5 million pieces of direct mail to diesel car owners in Tokyo; visiting 100 shippers' organizations all over Japan; conducting surveys of 2,000 major businesses nationwide on their current regulation measures; and a crackdown on transport delivery points at a total of 300 places.

While making efforts to ask diesel car owners and their clients to comply with the ordinance, TMG tried to raise citizens' awareness by conducting an online policy debate, "Diesel, Yes or No," as well as a public debate.

From late 1960s to early 1970s, TMG and some other local governments established industrial pollution regulations that were ahead of the national government's, and these local government initiatives persuaded the national government to follow with national legislation. No similar case had occurred during the intervening 30 years. However, timely and speedily implemented measures are needed to protect the environment. It is more important to change locally without waiting for national policy leadership. When local areas change, so does the nation. We want to support this kind of movement.

Written by Nobuko Saigusa