Air & Transportation

Environmental Quality Standards in Japan - Air Quality

1. Environmental Quality Standards in Japan

SubstanceEnvironmental conditionsMeasuring method
Sulfur dioxide The daily average for hourly values shall not exceed 0.04 ppm, and hourly values shall not exceed 0.1 ppm (Notification on May 16, 1973) Conductometric method or ultraviolet fluorescence method
Carbon monoxide The daily average for hourly values shall not exceed 10 ppm, and average of hourly values for any consecutive eight hour period shall not exceed 20ppm (Notification on May 8, 1973) Nondispersive infrared analyzer method
Suspended particulate matter The daily average for hourly values shall not exceed 0.10 mg/m3, and hourly values shall not exceed 0.20 mg/m3 (Notification on May 8, 1973) Weight concentration measuring methods based on filtration collection, or light scattering method; or piezoelectric microbalance method; or β-ray attenuation method that yields values having a linear relation with the values of the above methods.
Nitrogen dioxide The daily average for hourly values shall be within the 0.04-0.06 ppm zone or below that zone (Notification on July 11, 1978) Colorimetry employing Saltzman reagent (with Saltzman's coefficient being 0.84) or chemiluminescent method using ozone.
Photochemical oxidants Hourly values shall not exceed 0.06 ppm (Notification on May 8, 1973) Absorption spectrophotometry using a neutral potassium iodide solution; coulometry; ultraviolet absorption spectrometry; or chemiluminescent method using ethylene.
  1. Suspended particulate matter is defined as airborne particles with a diameter smaller than or equal to 10 μm.
  2. Photochemical oxidants are oxidizing substances such as ozone and peroxiacetyl nitrate produced by photochemical reactions (only those capable of isolating iodine from neutral potassium iodide , excluding nitrogen dioxide.)

2. Environmental Quality Standards for Benzene, Trichloroethylene, Tetrachloroethylene and Dichloromethane

(Notification on February 4th,1997)

SubstanceEnvironmental conditionsMeasuring method
Benzene Annual average shall not exceed 0.003 mg/m3 (Notification on February 4,1997) Preference method: gas chromatograph-mass spectrometer (sample gas should be collected with a canister or tube) or equivalent method.
Trichloroethylene Annual average shall not exceed 0.2 mg/m3 (Notification on February 4,1997)
Tetrachloroethylene Annual average shall not exceed 0.2 mg/m3 (Notification on February 4,1997)
Dichloromethane Annual average shall not exceed 0.15 mg/m3 (Notification on April 20,2001)

3. Environmental Quality Standards for Dioxins

(Notification on December 27,1999)

SubstanceEnvironmental conditionsMeasuring method
Dioxins
(PCDDs,PCDFs and coplanar PCBs)
Annual average shall not exceed 0.6pg-TEQ/m3 Using high resolution gas chromatograph - high resolution mass spectrometry (HRGC-HRMS). (Samples should be collected by an air sampler equipped with an inlet filter followed by a cartridge filled with polyurethane foam.)

4. Environmental Quality Standards for the PM2.5

SubstanceEnvironmental conditionsMeasuring method
Fine Particulate Matter (PM2.5) The annual standard for PM2.5 is less than or equal to 15.0 μg/m3. The 24 hour standard, which means the annual 98th percentile values at designated monitoring sites in an area, is less than or equal to 35μg/m3.
(Notification on September 9, 2009)
Mass measurement with filter sample collection which is designated as a reference method, or alternative automated methods, designated as equivalent methods, which are proved to have measurement performance comparable to the corresponding reference method.
  1. Fine Particulate Matter is defined as airborne particles that pass through a size-selective inlet with a 50 % efficiency cut-off at 2.5 μm aerodynamic diameter.
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