PM2.5 Assessment in Tokyo in FY2015

 Tokyo Metropolitan Government (TMG) continuously monitors Tokyo's air quality.
  Tokyo's PM2.5 is measured in all 82 air quality monitoring stations (47 ambient air monitoring stations and 35 roadside air pollution monitoring stations).

 In the ambient air monitoring stations, the annual average of PM2.5 in FY2015 was 13.8μg/m3, which was a 2.2μg/m3 decrease from the previous year. In the roadside air pollution monitoring stations, the annual average in FY2015 was 15.0μg/m3, a fall of 2.2μg/m3 from the previous year.

 In Japan, there are two types of national environmental standards for PM2.5, a short-term standard and a long-term standard.
 As for the short-term standard, 41 out of 47 ambient air monitoring stations and 28 out of 35 roadside air pollution monitoring stations achieved the standard. Regarding the long-term standard, 42 out of 47 ambient air monitoring stations and 14 out of 35 roadside air pollution monitoring stations achieved the standard.

 The chart below shows the number of stations that achieved both the short-term standard and the long-term standard.

Annual average of PM2.5 and environmental standards achievement
FY2015 FY2014 FY2013 FY2012
Ambient Air Monitoring Station Annual average
(μg / m3)
13.8 16 15.8 14.2
Number of stations achieving the standards
(Achievement rate)
40/47
(85%)
3/46
(6.5%)
3/45
(6.7%)
20/31
(65%)
Roadside Air Pollution Monitoring Station Annual average
(μg / m3)
15 17.2 16.7 15.9
Number of stations achieving the standards
(Achievement rate)
14/35
(40%)
0/35
(0%)
0/35
(0%)
6/24
(25%)

 Besides environmental standards, the Ministry of the Environment decides a provisional guideline on PM2.5 According to the guideline, when the daily average exceeds 70μg/m3, municipalities should consider notifying people.
 In Tokyo, we have not experienced a single day over the value given in the guidelines since they were introduced.

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