Radiation doses in the air / Measurement results by the hour (Koto)

We continuously measure radiation doses in the air (air absorbed doses per hour) at monitoring posts. Measurement results can be obtained by the minute, and we gather measurement data and then display them by the hour or by the day.

The maximum value indicates the largest value measured in each time slot (during the hour or during the day), the minimum value the smallest value measured in each time slot, and the average value is the average value for each time slot.

【News about this monitoring post】

We will suspend the provision of data in part or whole of the following time slots by interruption of power supply and relevant facilities due to maintenance and inspection of equipment.

From 10:00 to 13:00 on Tuesday, February 6,2018 Hachioji
From 13:00 to 16:00 on Tuesday, February 6,2018 Kodaira
From 10:00 to 13:00 on Wednesday, February 7,2018 Chofu
From 13:00 to 16:00 on Wednesday, February 7,2018 Ota
From 10:00 to 13:00 on Thursday, February 8,2018 Adachi
From 13:00 to 16:00 on Thursday, February 8,2018 Edogawa
From 10:00 to 13:00 on Friday, February 9,2018 Shinjuku







We will suspend the provision of data in part or whole of the following time slots by interruption of power supply and relevant facilities due to maintenance and inspection of equipment.

From Monday, March 13, 2017 to Tuesday, March 14, 2017

Shown in µGy/h (microgray per hour)

Gray indicates an amount of energy (absorbed dose) when radiation hits a material object, and 1 gray (Gy) of radiation doses in the air can be converted to 1 sievert (Sv).

Measurement time Dose rate
μGy/h (microgray per hour)
Maximum value Minimum value Average value
13:01-14:00, Tue., 20 Feb. 0.0378 0.0335 0.0358
12:01-13:00, Tue., 20 Feb. 0.0383 0.0336 0.0359
11:01-12:00, Tue., 20 Feb. 0.0376 0.0335 0.0357
10:01-11:00, Tue., 20 Feb. 0.0377 0.0343 0.0359
09:01-10:00, Tue., 20 Feb. 0.0385 0.0337 0.0360
08:01-09:00, Tue., 20 Feb. 0.0382 0.0340 0.0358
07:01-08:00, Tue., 20 Feb. 0.0383 0.0340 0.0361
06:01-07:00, Tue., 20 Feb. 0.0389 0.0336 0.0360
05:01-06:00, Tue., 20 Feb. 0.0388 0.0339 0.0360
04:01-05:00, Tue., 20 Feb. 0.0375 0.0340 0.0357
03:01-04:00, Tue., 20 Feb. 0.0375 0.0334 0.0357
02:01-03:00, Tue., 20 Feb. 0.0397 0.0337 0.0359
01:01-02:00, Tue., 20 Feb. 0.0373 0.0337 0.0357
00:01-01:00, Tue., 20 Feb. 0.0383 0.0337 0.0357
23:01-24:00, Mon., 19 Feb. 0.0378 0.0336 0.0357
22:01-23:00, Mon., 19 Feb. 0.0373 0.0334 0.0355
21:01-22:00, Mon., 19 Feb. 0.0384 0.0335 0.0357
20:01-21:00, Mon., 19 Feb. 0.0388 0.0340 0.0357
19:01-20:00, Mon., 19 Feb. 0.0380 0.0333 0.0357
18:01-19:00, Mon., 19 Feb. 0.0390 0.0338 0.0359
17:01-18:00, Mon., 19 Feb. 0.0386 0.0338 0.0360
16:01-17:00, Mon., 19 Feb. 0.0378 0.0329 0.0355
15:01-16:00, Mon., 19 Feb. 0.0380 0.0339 0.0358
14:01-15:00, Mon., 19 Feb. 0.0378 0.0337 0.0359
13:01-14:00, Mon., 19 Feb. 0.0382 0.0338 0.0356
12:01-13:00, Mon., 19 Feb. 0.0381 0.0340 0.0359
11:01-12:00, Mon., 19 Feb. 0.0375 0.0338 0.0357
10:01-11:00, Mon., 19 Feb. 0.0376 0.0337 0.0359
09:01-10:00, Mon., 19 Feb. 0.0381 0.0333 0.0358
08:01-09:00, Mon., 19 Feb. 0.0387 0.0337 0.0358
07:01-08:00, Mon., 19 Feb. 0.0383 0.0335 0.0357
06:01-07:00, Mon., 19 Feb. 0.0391 0.0338 0.0358
05:01-06:00, Mon., 19 Feb. 0.0381 0.0338 0.0361
04:01-05:00, Mon., 19 Feb. 0.0377 0.0322 0.0357
03:01-04:00, Mon., 19 Feb. 0.0383 0.0338 0.0359
02:01-03:00, Mon., 19 Feb. 0.0384 0.0333 0.0358
01:01-02:00, Mon., 19 Feb. 0.0384 0.0341 0.0360
00:01-01:00, Mon., 19 Feb. 0.0384 0.0338 0.0359
23:01-24:00, Sun., 18 Feb. 0.0378 0.0333 0.0358
22:01-23:00, Sun., 18 Feb. 0.0378 0.0332 0.0358
21:01-22:00, Sun., 18 Feb. 0.0381 0.0334 0.0359
20:01-21:00, Sun., 18 Feb. 0.0377 0.0339 0.0357
19:01-20:00, Sun., 18 Feb. 0.0379 0.0326 0.0356
18:01-19:00, Sun., 18 Feb. 0.0379 0.0338 0.0357
17:01-18:00, Sun., 18 Feb. 0.0375 0.0337 0.0357
16:01-17:00, Sun., 18 Feb. 0.0375 0.0339 0.0356
15:01-16:00, Sun., 18 Feb. 0.0390 0.0332 0.0359
14:01-15:00, Sun., 18 Feb. 0.0385 0.0334 0.0357
13:01-14:00, Sun., 18 Feb. 0.0379 0.0332 0.0354
12:01-13:00, Sun., 18 Feb. 0.0380 0.0337 0.0356
11:01-12:00, Sun., 18 Feb. 0.0395 0.0335 0.0357
10:01-11:00, Sun., 18 Feb. 0.0376 0.0331 0.0356
09:01-10:00, Sun., 18 Feb. 0.0383 0.0340 0.0358
08:01-09:00, Sun., 18 Feb. 0.0380 0.0331 0.0359
07:01-08:00, Sun., 18 Feb. 0.0376 0.0332 0.0358
06:01-07:00, Sun., 18 Feb. 0.0379 0.0338 0.0358
05:01-06:00, Sun., 18 Feb. 0.0384 0.0333 0.0358
04:01-05:00, Sun., 18 Feb. 0.0383 0.0335 0.0360
03:01-04:00, Sun., 18 Feb. 0.0381 0.0336 0.0357
02:01-03:00, Sun., 18 Feb. 0.0376 0.0345 0.0359
01:01-02:00, Sun., 18 Feb. 0.0381 0.0338 0.0358
00:01-01:00, Sun., 18 Feb. 0.0386 0.0339 0.0359
23:01-24:00, Sat., 17 Feb. 0.0386 0.0340 0.0359
22:01-23:00, Sat., 17 Feb. 0.0387 0.0342 0.0362
21:01-22:00, Sat., 17 Feb. 0.0379 0.0340 0.0361
20:01-21:00, Sat., 17 Feb. 0.0380 0.0334 0.0361
19:01-20:00, Sat., 17 Feb. 0.0385 0.0334 0.0362
18:01-19:00, Sat., 17 Feb. 0.0394 0.0337 0.0361
17:01-18:00, Sat., 17 Feb. 0.0386 0.0336 0.0365
16:01-17:00, Sat., 17 Feb. 0.0393 0.0347 0.0369
15:01-16:00, Sat., 17 Feb. 0.0428 0.0364 0.0387
14:01-15:00, Sat., 17 Feb. 0.0415 0.0351 0.0379
13:01-14:00, Sat., 17 Feb. 0.0385 0.0335 0.0358
12:01-13:00, Sat., 17 Feb. 0.0374 0.0331 0.0354
11:01-12:00, Sat., 17 Feb. 0.0374 0.0337 0.0355
10:01-11:00, Sat., 17 Feb. 0.0381 0.0334 0.0355
09:01-10:00, Sat., 17 Feb. 0.0377 0.0334 0.0354
08:01-09:00, Sat., 17 Feb. 0.0386 0.0334 0.0357
07:01-08:00, Sat., 17 Feb. 0.0382 0.0339 0.0357
06:01-07:00, Sat., 17 Feb. 0.0373 0.0334 0.0358
05:01-06:00, Sat., 17 Feb. 0.0381 0.0329 0.0359
04:01-05:00, Sat., 17 Feb. 0.0385 0.0330 0.0357
03:01-04:00, Sat., 17 Feb. 0.0377 0.0335 0.0357
02:01-03:00, Sat., 17 Feb. 0.0377 0.0343 0.0358
01:01-02:00, Sat., 17 Feb. 0.0375 0.0321 0.0356
00:01-01:00, Sat., 17 Feb. 0.0387 0.0330 0.0357
23:01-24:00, Fri., 16 Feb. 0.0379 0.0338 0.0358
22:01-23:00, Fri., 16 Feb. 0.0379 0.0336 0.0355
21:01-22:00, Fri., 16 Feb. 0.0377 0.0334 0.0357
20:01-21:00, Fri., 16 Feb. 0.0383 0.0338 0.0360
19:01-20:00, Fri., 16 Feb. 0.0379 0.0337 0.0356
18:01-19:00, Fri., 16 Feb. 0.0378 0.0338 0.0357
17:01-18:00, Fri., 16 Feb. 0.0381 0.0336 0.0359
16:01-17:00, Fri., 16 Feb. 0.0384 0.0338 0.0357
15:01-16:00, Fri., 16 Feb. 0.0375 0.0339 0.0357
14:01-15:00, Fri., 16 Feb. 0.0373 0.0332 0.0355
13:01-14:00, Fri., 16 Feb. 0.0385 0.0338 0.0359
12:01-13:00, Fri., 16 Feb. 0.0380 0.0338 0.0359
11:01-12:00, Fri., 16 Feb. 0.0376 0.0329 0.0358
10:01-11:00, Fri., 16 Feb. 0.0378 0.0335 0.0357
09:01-10:00, Fri., 16 Feb. 0.0379 0.0334 0.0356
08:01-09:00, Fri., 16 Feb. 0.0383 0.0341 0.0359
07:01-08:00, Fri., 16 Feb. 0.0387 0.0337 0.0357
06:01-07:00, Fri., 16 Feb. 0.0376 0.0335 0.0358
05:01-06:00, Fri., 16 Feb. 0.0381 0.0333 0.0354
04:01-05:00, Fri., 16 Feb. 0.0375 0.0342 0.0358
03:01-04:00, Fri., 16 Feb. 0.0385 0.0333 0.0358
02:01-03:00, Fri., 16 Feb. 0.0383 0.0339 0.0360
01:01-02:00, Fri., 16 Feb. 0.0379 0.0332 0.0356
00:01-01:00, Fri., 16 Feb. 0.0377 0.0336 0.0354
23:01-24:00, Thu., 15 Feb. 0.0378 0.0335 0.0357
22:01-23:00, Thu., 15 Feb. 0.0379 0.0321 0.0355
21:01-22:00, Thu., 15 Feb. 0.0381 0.0335 0.0359
20:01-21:00, Thu., 15 Feb. 0.0377 0.0332 0.0357
19:01-20:00, Thu., 15 Feb. 0.0387 0.0333 0.0358
18:01-19:00, Thu., 15 Feb. 0.0382 0.0335 0.0359
17:01-18:00, Thu., 15 Feb. 0.0377 0.0337 0.0359
16:01-17:00, Thu., 15 Feb. 0.0386 0.0341 0.0359
15:01-16:00, Thu., 15 Feb. 0.0382 0.0332 0.0360
14:01-15:00, Thu., 15 Feb. 0.0389 0.0340 0.0359
13:01-14:00, Thu., 15 Feb. 0.0381 0.0335 0.0357
12:01-13:00, Thu., 15 Feb. 0.0381 0.0336 0.0358
11:01-12:00, Thu., 15 Feb. 0.0442 0.0334 0.0360
10:01-11:00, Thu., 15 Feb. 0.0379 0.0332 0.0355
09:01-10:00, Thu., 15 Feb. 0.0384 0.0336 0.0359
08:01-09:00, Thu., 15 Feb. 0.0384 0.0340 0.0358
07:01-08:00, Thu., 15 Feb. 0.0379 0.0337 0.0358
06:01-07:00, Thu., 15 Feb. 0.0380 0.0337 0.0357
05:01-06:00, Thu., 15 Feb. 0.0386 0.0338 0.0358
04:01-05:00, Thu., 15 Feb. 0.0382 0.0334 0.0358
03:01-04:00, Thu., 15 Feb. 0.0381 0.0335 0.0357
02:01-03:00, Thu., 15 Feb. 0.0376 0.0328 0.0357
01:01-02:00, Thu., 15 Feb. 0.0384 0.0341 0.0358
00:01-01:00, Thu., 15 Feb. 0.0382 0.0335 0.0357
23:01-24:00, Wed., 14 Feb. 0.0383 0.0342 0.0359
22:01-23:00, Wed., 14 Feb. 0.0378 0.0339 0.0357
21:01-22:00, Wed., 14 Feb. 0.0379 0.0340 0.0356
20:01-21:00, Wed., 14 Feb. 0.0379 0.0334 0.0358
19:01-20:00, Wed., 14 Feb. 0.0375 0.0339 0.0355
18:01-19:00, Wed., 14 Feb. 0.0376 0.0334 0.0358
17:01-18:00, Wed., 14 Feb. 0.0390 0.0336 0.0357
16:01-17:00, Wed., 14 Feb. 0.0378 0.0335 0.0358
15:01-16:00, Wed., 14 Feb. 0.0382 0.0339 0.0358
14:01-15:00, Wed., 14 Feb. 0.0377 0.0344 0.0357
13:01-14:00, Wed., 14 Feb. 0.0374 0.0333 0.0357
12:01-13:00, Wed., 14 Feb. 0.0382 0.0337 0.0359
11:01-12:00, Wed., 14 Feb. 0.0389 0.0333 0.0357
10:01-11:00, Wed., 14 Feb. 0.0380 0.0332 0.0358
09:01-10:00, Wed., 14 Feb. 0.0380 0.0334 0.0355
08:01-09:00, Wed., 14 Feb. 0.0378 0.0332 0.0362
07:01-08:00, Wed., 14 Feb. 0.0387 0.0341 0.0360
06:01-07:00, Wed., 14 Feb. 0.0386 0.0338 0.0359
05:01-06:00, Wed., 14 Feb. 0.0384 0.0340 0.0358
04:01-05:00, Wed., 14 Feb. 0.0375 0.0342 0.0358
03:01-04:00, Wed., 14 Feb. 0.0388 0.0336 0.0358
02:01-03:00, Wed., 14 Feb. 0.0382 0.0338 0.0357
01:01-02:00, Wed., 14 Feb. 0.0374 0.0341 0.0356
00:01-01:00, Wed., 14 Feb. 0.0382 0.0332 0.0356
23:01-24:00, Tue., 13 Feb. 0.0379 0.0332 0.0354
22:01-23:00, Tue., 13 Feb. 0.0377 0.0332 0.0355
21:01-22:00, Tue., 13 Feb. 0.0386 0.0330 0.0358
20:01-21:00, Tue., 13 Feb. 0.0376 0.0339 0.0356
19:01-20:00, Tue., 13 Feb. 0.0375 0.0339 0.0357
18:01-19:00, Tue., 13 Feb. 0.0382 0.0340 0.0359
17:01-18:00, Tue., 13 Feb. 0.0378 0.0338 0.0359
16:01-17:00, Tue., 13 Feb. 0.0377 0.0331 0.0357
15:01-16:00, Tue., 13 Feb. 0.0385 0.0336 0.0359
14:01-15:00, Tue., 13 Feb. 0.0378 0.0339 0.0359
13:01-14:00, Tue., 13 Feb. 0.0387 0.0331 0.0359
12:01-13:00, Tue., 13 Feb. 0.0391 0.0336 0.0358
11:01-12:00, Tue., 13 Feb. 0.0384 0.0332 0.0355
10:01-11:00, Tue., 13 Feb. 0.0382 0.0341 0.0359
09:01-10:00, Tue., 13 Feb. 0.0374 0.0332 0.0354
08:01-09:00, Tue., 13 Feb. 0.0379 0.0339 0.0358
07:01-08:00, Tue., 13 Feb. 0.0379 0.0335 0.0358
06:01-07:00, Tue., 13 Feb. 0.0380 0.0338 0.0356
05:01-06:00, Tue., 13 Feb. 0.0388 0.0325 0.0359
04:01-05:00, Tue., 13 Feb. 0.0388 0.0337 0.0359
03:01-04:00, Tue., 13 Feb. 0.0379 0.0332 0.0354
02:01-03:00, Tue., 13 Feb. 0.0374 0.0341 0.0357
01:01-02:00, Tue., 13 Feb. 0.0382 0.0335 0.0356
00:01-01:00, Tue., 13 Feb. 0.0379 0.0338 0.0356
23:01-24:00, Mon., 12 Feb. 0.0375 0.0337 0.0355
22:01-23:00, Mon., 12 Feb. 0.0385 0.0335 0.0357
21:01-22:00, Mon., 12 Feb. 0.0383 0.0337 0.0358
20:01-21:00, Mon., 12 Feb. 0.0383 0.0340 0.0358
19:01-20:00, Mon., 12 Feb. 0.0378 0.0334 0.0357
18:01-19:00, Mon., 12 Feb. 0.0383 0.0338 0.0359
17:01-18:00, Mon., 12 Feb. 0.0384 0.0336 0.0357
16:01-17:00, Mon., 12 Feb. 0.0393 0.0337 0.0360
15:01-16:00, Mon., 12 Feb. 0.0381 0.0325 0.0357
14:01-15:00, Mon., 12 Feb. 0.0378 0.0328 0.0356
13:01-14:00, Mon., 12 Feb. 0.0384 0.0333 0.0358
12:01-13:00, Mon., 12 Feb. 0.0396 0.0334 0.0357
11:01-12:00, Mon., 12 Feb. 0.0377 0.0339 0.0358
10:01-11:00, Mon., 12 Feb. 0.0376 0.0341 0.0357
09:01-10:00, Mon., 12 Feb. 0.0377 0.0334 0.0355
08:01-09:00, Mon., 12 Feb. 0.0376 0.0341 0.0356
07:01-08:00, Mon., 12 Feb. 0.0385 0.0338 0.0355
06:01-07:00, Mon., 12 Feb. 0.0382 0.0337 0.0357
05:01-06:00, Mon., 12 Feb. 0.0382 0.0331 0.0356
04:01-05:00, Mon., 12 Feb. 0.0375 0.0334 0.0355
03:01-04:00, Mon., 12 Feb. 0.0386 0.0338 0.0357
02:01-03:00, Mon., 12 Feb. 0.0386 0.0339 0.0360
01:01-02:00, Mon., 12 Feb. 0.0378 0.0337 0.0357
00:01-01:00, Mon., 12 Feb. 0.0373 0.0335 0.0356
23:01-24:00, Sun., 11 Feb. 0.0387 0.0329 0.0357
22:01-23:00, Sun., 11 Feb. 0.0382 0.0337 0.0359
21:01-22:00, Sun., 11 Feb. 0.0379 0.0339 0.0358
20:01-21:00, Sun., 11 Feb. 0.0374 0.0335 0.0357
19:01-20:00, Sun., 11 Feb. 0.0378 0.0333 0.0357
18:01-19:00, Sun., 11 Feb. 0.0378 0.0340 0.0357
17:01-18:00, Sun., 11 Feb. 0.0383 0.0334 0.0360
16:01-17:00, Sun., 11 Feb. 0.0374 0.0333 0.0355
15:01-16:00, Sun., 11 Feb. 0.0378 0.0334 0.0357
14:01-15:00, Sun., 11 Feb. 0.0384 0.0335 0.0357
13:01-14:00, Sun., 11 Feb. 0.0386 0.0330 0.0357
12:01-13:00, Sun., 11 Feb. 0.0380 0.0337 0.0357
11:01-12:00, Sun., 11 Feb. 0.0373 0.0341 0.0358
10:01-11:00, Sun., 11 Feb. 0.0380 0.0336 0.0356
09:01-10:00, Sun., 11 Feb. 0.0377 0.0339 0.0357
08:01-09:00, Sun., 11 Feb. 0.0380 0.0332 0.0357
07:01-08:00, Sun., 11 Feb. 0.0384 0.0331 0.0359
06:01-07:00, Sun., 11 Feb. 0.0384 0.0339 0.0361
05:01-06:00, Sun., 11 Feb. 0.0386 0.0335 0.0359
04:01-05:00, Sun., 11 Feb. 0.0379 0.0341 0.0360
03:01-04:00, Sun., 11 Feb. 0.0389 0.0331 0.0360
02:01-03:00, Sun., 11 Feb. 0.0381 0.0337 0.0355
01:01-02:00, Sun., 11 Feb. 0.0377 0.0334 0.0356
00:01-01:00, Sun., 11 Feb. 0.0385 0.0334 0.0360
23:01-24:00, Sat., 10 Feb. 0.0397 0.0351 0.0368
22:01-23:00, Sat., 10 Feb. 0.0403 0.0354 0.0379
21:01-22:00, Sat., 10 Feb. 0.0389 0.0355 0.0373
20:01-21:00, Sat., 10 Feb. 0.0385 0.0349 0.0366
19:01-20:00, Sat., 10 Feb. 0.0376 0.0342 0.0359
18:01-19:00, Sat., 10 Feb. 0.0383 0.0333 0.0357
17:01-18:00, Sat., 10 Feb. 0.0383 0.0335 0.0357
16:01-17:00, Sat., 10 Feb. 0.0379 0.0332 0.0356
15:01-16:00, Sat., 10 Feb. 0.0383 0.0337 0.0359
14:01-15:00, Sat., 10 Feb. 0.0377 0.0337 0.0359