Air & Transportation

Environmental quality standards for noise

Environment Agency Notification No. 64, September 30, 1998

The environmental quality standards for noise, which are in accordance with the provisions of Paragraph 1, Article 16 of the Basic Environment Law (Law No. 91 of 1993), are notified as follows.

The standards for regulating the environmental conditions of noise, in accordance with Paragraph 1, Article 16 of the Basic Environment Law (hereinafter referred to as "environmental quality standards"), shall be as follows, in addition to other notification. The maintenance of these standards is desirable for the preservation of the living environment and is conductive to the protection of human health.

I. Environmental Quality Standards

1. The environmental quality standards shall be as shown in the columns of the standard values in the following table for each area type and time category, and the prefectural governors shall designate the areas to which each area type is to be applied.

Standard value
Type of areaDaytimeNighttime
AA 50 dB or less 40 dB or less
A and B 55 dB or less 45 dB or less
C 60 dB or less 50 dB or less
Notes:
1)
In terms of the time category, daytime shall be the period from 6:00 a.m. to 10:00 p.m. and nighttime shall be the period from 10:00 p.m. to 6:00 a.m. of the following day.
2)
Area category AA shall be applied to areas where quietness is specially required, such as those where convalescent facilities and welfare institutions are concentrated.
3)
Area category A shall be applied to areas used exclusively for residences.
4)
Area category B shall be applied to areas used mainly for residences.
5)
Area category C shall be applied to areas used for commerce and industry as well as for a significant number of residences.

For areas corresponding to the ones mentioned in the following table (hereinafter referred to as "areas facing roads"), the standard values in this table shall be applied instead of the table above.

Standard value
Area categoryDaytimeNighttime
Area A facing roads with two or more lanes 60 dB or less 55 dB or less
Area B facing roads with two or more lanes,
and area C facing a road with one or more lanes
65 dB or less 60 dB or less
Note:
"Lane" refers to a longitudinal strip of road with uniform width to enable a single line of cars to travel safely and without hindrance.

In this case, standard values given in the following table shall be applied to the space adjacent to a road carrying arterial traffic as an exception regardless of the preceding table for areas facing roads.

Standard values
DaytimeNighttime
70 dB or less 65 dB or less
Note:
Standards for indoor noise transmitted from the outside (45 dB or less for daytime, and 40 dB or less for nighttime) can be applied for the respective residences whose windows are judged as usually closed on the sides most affected by noise.

2. Values of the environmental quality standards referred to in Paragraph 1 shall be evaluated by the following method.

  • (1) Noise levels to which the respective buildings are exposed shall be evaluated. Noise levels at the sides of residential buildings most affected by noise shall be evaluated. Indoor noise transmitted from the outside shall be evaluated by subtracting sound insulation of the building from the levels measured at the sides of the building most affected by noise.
  • (2) Noise shall be evaluated by the equivalent continuous A-weighted sound pressure levels, in principle, throughout the hours of the respective time categories.
  • (3) Evaluation shall be conducted by selecting a day or days showing the average conditions of noise throughout the year.
  • (4) According to the method specified by the Japanese Industrial Standards Z8731, in evaluating the environmental quality standards for noise, if the effect of noise reflected by the concerned building hinders evaluation, the noise level shall be measured where the hindrance can be avoided. In case it is difficult, appropriate steps shall be made such as correcting measured values. In case noise cannot be measured for the required period, its level can be estimated from conditions such as the volume of road traffic instead of the actual measurement.

3. Area-wide evaluation of the achievement of environmental quality standards shall be made using the following methods.

  • (1) For areas other than those facing roads, achievement shall in principle be evaluated by choosing points considered to represent the noise of the respective concerned areas.
  • (2) For areas facing roads, achievement shall in principle be evaluated by obtaining numbers and rates of the houses at which noise levels exceed the environmental quality standards stipulated for the respective areas.
    II. Target dates for achievement

II. Target dates for achievement

1. The environmental quality standards must be achieved or maintained within the forget dates shown below.

  • (1) Efforts must be made to achieve or maintain the environmental quality standards immediately after these are enforced for areas other than the areas facing roads.
  • (2) Efforts must be made to achieve or maintain the environmental quality standards concerning the areas facing roads within ten years after the standards are enforced. Comprehensive measures, including those for motor vehicles, road structure improvement measures, traffic flow control measures, and roadside noise control measures, etc., shall be carried out with the cooperation of concerned administrative organizations and local governments. However, when the achievement of the environmental quality standards is extremely difficult in an area that faces a road carrying arterial traffic with heavy road traffic volume, efforts must be made to achieve the environmental quality standards as quickly as possible even after the ten-year period has expired, by incorporating drastic advances in technology for noise control measures and the reformation of urban structure, etc.
  • (3) When an area previously not facing a road has become an area facing a road, because of the construction of a road planned after the date on which the environmental quality standards were enforced, efforts must be made to achieve or maintain the relevant environmental quality standards immediately after the concerned road begins service, regardless of (1) and (2). When an area not previously facing a road becomes an area facing a road by the construction of a road planned before the date on which the environment quality standards were enforced, the rule mentioned in (2) shall be applied appropriately.

2. When remarkably loud noise directly reaches the sides most affected by noise of a residence located at medium or high level in a multi-story building sited on the land behind a space adjacent to a road facing arterial traffic within an area facing a road, and the windows are judged as usually closed at the sides and when the indoor standards for noise transmitted from the outside are satisfied, the environmental quality standards shall be considered to have been achieved.

3. Noise control measures shall be preferentially carried out for any area containing residences in which the noise level during nighttime has exceeded 73 dB.

III. Exemption from the Application of Environmental Quality Standards

These environment quality standards shall not be applied to aircraft noise, railway noise, or construction work noise.

Supplementary provisions

This notification shall be enforced on April 1, 1999.

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