Urban traffic is far below its usual level during this holiday-filled Golden Week period. On good days with fair skies, the public has the chance, as welcome as it is unexpected, for a foretaste of the cleaner air that is promised by tough new control measures for diesel engine-exhaust pollution soon to be introduced by the central government. If preliminary reports are correct, the government — after years of denying or minimizing any health threat posed by emissions from diesel-powered vehicles — has done a turnabout and plans to implement stricter regulations for this type of pollution starting in 2005, two years ahead of the original target date of 2007.

The government’s ostensible change of heart is bound to raise as many questions as it answers. It was only a little more than three months ago, after all, that the government joined with the Hanshin Expressway Public Corp. to file an appeal with the Osaka High Court against a Kobe District Court ruling that they should compensate a group of residents of Amagasaki, Hyogo Prefecture, for physical ailments they suffer as a likely result of pollution caused by suspended particulate matter, or SPM, in exhaust fumes from diesel-powered vehicles. In announcing its reasons for appealing the decision, the Construction Ministry took the dubious stand that medical evidence proving a link between SPM and health problems is still lacking.

Yet, the Environment Agency — which should be expected to have a more realistic viewpoint — had already decided to shift its emphasis from regulating nitrogen oxides in diesel-exhaust gases, which it had previously considered the main health threat in such emissions, to tougher controls on SPM, which scientific evidence increasingly points to as a clear and immediate danger to human health. In fact, the agency technically had adopted the change as early as 1993, although it took few concrete steps to support it and has been under growing fire for its inaction during the intervening years.

Among specialists who have seen and studied the results of research conducted abroad, these particles have long been known to cause respiratory diseases such as asthma and lung cancer. Unfortunately, the Environment Agency has done little to encourage similar research in this country. However, a group of scientists at the Tuberculosis Research Institute announced in March that their calculations indicate that the particles in diesel-vehicle emissions will be responsible for some 5,300 lung cancer deaths, or more than 10 percent of the national total of such fatalities, by 2020.

Even more unexpected was the statement from the National Institute for Environmental Studies at Tsukuba, in Ibaraki Prefecture, that the SPM element in diesel-engine exhausts may also contribute to circulatory problems, by making the heart muscles and major blood vessels contract and relax to an excessive degree. The institute, under the jurisdiction of the Environment Agency, only began its research on the subject, however, after the agency received a number of reports from the United States positing a link between heavy concentrations of the particles and deaths from circulatory disease.

Despite the lack of fanfare from the central government in announcing its new “fast-track” crackdown on pollution from diesel-powered vehicles, it is not difficult to detect an element of political gamesmanship in the proposals, coming as they do so soon after Tokyo Gov. Shintaro Ishihara announced his own plans for tougher controls on all types of pollution in the capital region. Central to the Tokyo Metropolitan Government’s plans are extremely strict regulations on diesel- engine emissions, including mandatory installation of diesel-particulate filters as early as 2003.

One of the first reactions from diesel-vehicle fleet owners, as well as individual owner-drivers, to this last possibility has been uproar over the likely expense of such conversions. Because demand at this time is low, the cost is indeed high. That may explain why a key element of the central government’s proposals is the guarantee of loans of up to 50 million yen for small and medium-size firms so they can replace older diesel vehicles with new, low-pollution ones.

Mr. Ishihara’s determination to go his own way with proposals for residents of the capital has led to a chill between the governor and Kasumigaseki. The public would like to see more cooperation and less confrontation. There has already been entirely too much political game-playing on environmental issues while the ordinary citizen suffers the consequences to health and pocketbook.

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.