Tokyo and its neighboring prefectures will debut regulations Wednesday to curb emissions from diesel-powered trucks and buses to clear up the region’s air pollution problem — the nation’s worst.

It is the first attempt by local governments to jointly impose stricter regulations than those set by the national government to control particulate matter emissions from diesel vehicles.

According to the Tokyo Metropolitan Government, the density of suspended particulate matter in all monitoring points in Tokyo in 2002 surpassed the national government’s acceptable levels. SPM is the fine black soot emitted from vehicle engines, especially diesels, and is believed to cause respiratory problems, including asthma.

To cope with the air pollution, Tokyo, Saitama, Chiba and Kanagawa prefectures will ban the operation of diesel-powered vehicles, except cars, if their particulate emissions exceed tight limits.

Under the new regulations, operators of diesel trucks and buses that do not meet the standards must either replace their fleet with cleaner vehicles or attach diesel-particulate filters approved by the local governments.

The rules apply to vehicles in use for seven years or more. Those that have not reached that age can keep running even though they do not meet the emission limit.

“The regulations will help reduce air pollution in the metropolis,” said Hirotaka Yamauchi, a professor at Hitotsubashi University in Tokyo.

Yamauchi, who has carried out research on traffic regulations, said he supports the initiative taken by Tokyo and its neighbors because it is an attempt to solve their own problems by themselves instead of waiting for the national government to act.

Under the regulations, the Tokyo Metropolitan Government, for example, will ban diesel trucks that weigh 3.5 tons or more if the vehicles emit 0.25 grams or more of particulate matter to produce the electricity equivalent of 1 kilowatt hour.

The maximum emission level is the same as the one being phased in since last year by the national government in eight prefectures that have serious traffic congestion — Tokyo, Saitama, Chiba, Kanagawa, Osaka, Hyogo, Aichi and Mie.

The Tokyo government plans to inspect diesel vehicles, including those coming in from other prefectures, in cooperation with police. Under the national curbs, however, vehicles that fail to meet the criteria are still allowed to run anywhere in the country if they are registered outside the eight designated prefectures.

Under the national regulations, vehicles will be checked against the emission limit at the time of mandatory safety checks.

If truck and bus operators violate the Tokyo metropolitan regulations, they face a fine of 500,000 yen. Violating the national regulations can fetch up to six months in prison or up to 200,000 yen in fines.

Tokyo and Saitama plan to tighten the limits further in two years, banning vehicles that emit 0.18 grams or more of particulate matter per kwh beginning in 2005 — the same emission limit currently imposed by the national government on new vehicles.

According to the Land, Infrastructure and Transport Ministry, the national emission limits were set by taking into account the worsening air pollution in certain regions as well as technological progress in vehicle engines and particulate filters.

The metropolitan government’s rules, on the other hand, are set to be stricter than those imposed by the national government, Tokyo officials said.

“Regulations set by Tokyo and its neighbors will be more drastic than those of the national government,” said Matsuo Odaka, executive director of the National Traffic Safety and Environment Laboratory, an independent entity in Tokyo.

Tokyo and its neighboring prefectures would not have introduced the regulations if Tokyo Gov. Shintaro Ishihara had not taken the initiative, Odaka said.

The regulations were spearheaded by Ishihara, who has singled out particulate emissions from diesel-powered vehicles as a major source of air pollution in the metropolis.

Ishihara has complained that people living and working in the Tokyo area face a higher risk of respiratory problems than those in other prefectures due to the large number of vehicles flowing into the metropolis from all over Japan.

In 2005, the national government will further tighten exhaust restrictions, requiring diesel-engine vehicles weighing 3.5 tons or more to cut particulate matter emissions to 0.027 grams per kwh — one of the world’s toughest standards.

Still, Ishihara has been criticizing the national government for being slow in its pollution fight, saying it has yet to take any effective measures to combat the worsening problem.

In a booklet released earlier this month, the metropolitan government emphasized that Tokyo’s regulations are more advanced than the national limits.

However, the metropolitan government has had to modify its plans in introducing the regulations as both vehicle users and particulate-filter producers were unprepared.

The filter supply has not kept up with demand from diesel-vehicle operators. Tokyo and its neighboring prefectures announced in mid-September that diesel vehicles without the filters can run through the end of this year if they can prove, with the appropriate official certificate, that they are on the waiting list for a filter.

Tokyo has also announced it will resume accepting applications from diesel-vehicle operators for filter-buying subsidies. Although it earlier set August as the deadline, more and more operators and owners, apparently unaware or unprepared, continued to seek special treatment after missing the deadline.

The metropolitan government has meanwhile urged Internet operator Yahoo Japan Corp. to delete the account of a seller on its auction site that offered stickers showing official approval of vehicles in line with emission regulations. The provider yanked the information in about a week.

“We are considering criminal action for suspected forgery of official documents, to show our determination to fight this type of crime,” Ishihara told reporters recently.

Odaka of the National Traffic Safety and Environment Laboratory said he is skeptical that the new regulations will have the intended effect. Technical improvements in particulate filters have yet to catch up with the emissions curbs, he said.

For example, engines in vehicles currently in use are not designed to run with the filters attached, and it is questionable if the filters will perform as well as they did in laboratory tests.

“I’m not sure the filters will be as effective as Tokyo and its neighbors hope,” Okada said. “We must closely monitor how well the regulations reduce air pollution.”

In a time of both misinformation and too much information, quality journalism is more crucial than ever.
By subscribing, you can help us get the story right.