Air & Transportation

Future Policy for Motor Vehicle Exhaust Emission Reduction(second report) - Chapter 1


The motor vehicle exhaust emission regulations in Japan have been enforced since the year 1966 when the concentration of carbon monoxide from ordinary-sized and small-sized motor vehicles fueled by gasoline began to be controlled for the first time. After that, mini-sized motor vehicles, motor vehicles fueled by liquefied petroleum gas (LPG), and diesel-powered motor vehicles also became subject to the exhaust emission standards. Furthermore, the list of substances to be controlled was being added to continually. Currently, carbon monoxide, hydrocarbons, and nitrogen oxides are regulated for motor vehicles fueled by gasoline or LPG (gasoline·LPG motor vehicles). In addition to these three substances, particulate matter, particularly diesel smoke, is regulated for diesel-powered motor vehicles. Permissible concentrations have been reviewed and made stricter on an on-going basis.

Furthermore, the Air Pollution Control Law was amended partially in April 1995. As a result, permissible limits for automotive fuel quality were established for gasoline and diesel oil. Based on this provision, the motor vehicle fuel quality regulation has been implemented since April 1996.

In recent years, measures for motor vehicle exhaust emission reduction have been advanced in accordance with the targets indicated in "Future Policy for Motor Vehicle Exhaust Emission Reduction" reported on December 22, 1989, by the Central Council for Environmental Pollution Control. The Report included the following measures: (i) Drastic reduction of nitrogen oxides, particulate matters, etc. emitted from diesel-powered motor vehicles, etc. in two stages according to short- and long-term targets and (ii) Reduction of the sulfur content of diesel oil to about one-tenth in two stages. All of these measures were scheduled to be implemented by 1999.

Moreover, having obtained a prospect to enforce the targets indicated in the 1989 Report completely, an inquiry concerning "Future Policy for Motor Vehicle Exhaust Emission Reduction" was made to the Central Environment Council through Inquiry No.31, dated May 21, 1996. Consequently, deliberations were started by the Air Quality Committee of the Central Environment Council and the Experts Committee on Motor Vehicle Emissions, which was newly established in the Air Quality Committee.

Concerning the motor vehicle exhaust emission reduction measures to be implemented as soon as possible in light of the importance and urgency of measures against hazardous air pollutants, the Experts Committee reported the results of its study to the Air Quality Committee on October 18, 1996. Based on the Report, "Future Policy for Motor Vehicle Exhaust Emission Reduction (Interim Report)" was submitted. Furthermore, based on the Report, the following measures were scheduled to be enforced in 1998 or 1999: (1) Emission reduction of hydrocarbons, etc. through introduction of an exhaust emission control standard for two-wheeled motor vehicles; (2) Emission reduction of hydrocarbons, etc. through strengthened exhaust emission control standards for gasoline·LPG motor vehicles; and (3) Employment of low-benzene gasoline by means of the regulations for automotive fuel quality.

The Experts Committee continually conducted studies of the general policy for motor vehicle exhaust emission reduction according to the study policy indicated in the 1996 Interim Report. As a result, deliberations were carried out on twenty-eight different occasions, including spot-investigations of and hearings for automobile manufacturers conducted by the working committee, which was established within the Experts Committee. Consequently, the following study results were obtained in connection with (i) Exhaust emission reduction measures for gasoline·LPG motor vehicles and (ii) Exhaust emission reduction for off-road vehicles (referring to large-sized off-road vehicles and small-sized off-road vehicles provided for in the Road Vehicles Act). Thus, the study results are reported as follows.

The conclusions of the Experts Committee are explained in this Report as follows: Section 2 explains the current status of the atmospheric environment, the formation mechanism of air pollutants and related motor vehicle exhaust emissions, and the basic approach to motor vehicle exhaust emission reduction; Section 3 reports on reduction measures for emissions from the exhaust pipes of gasoline·LPG motor vehicles; Section 4 covers reduction measures for hydrocarbons emitted as fuel evaporative emissions from gasoline motor vehicles; Section 5 reports on exhaust emission reduction measures for off-road vehicles; and Section 6 explains future study policy based on the study results described in Sections 2 - 5, and other related measures.

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