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 9:00 to 13:00 on Tuesday, June 26,2018 Hachioji
From 13:00 to 17:00 on Thursday, June 26,2018 Adachi
From 9:00 to 13:00 on Wednesday, June 27,2018 Chofu
From 13:00 to 17:00 on Wednesday, June 27,2018 Ota
From 9:00 to 13:00 on Thursday, June 28,2018 Kodaira 
From 13:00 to 17:00 on Thursday, June 28,2018 Edogawa
From 9:00 to 13:00 on Friday, June 29,2018 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
21:01-22:00, Thu., 20 Sep. 0.0421 0.0370 0.0398
20:01-21:00, Thu., 20 Sep. 0.0414 0.0372 0.0393
19:01-20:00, Thu., 20 Sep. 0.0421 0.0367 0.0390
18:01-19:00, Thu., 20 Sep. 0.0448 0.0370 0.0407
17:01-18:00, Thu., 20 Sep. 0.0484 0.0405 0.0437
16:01-17:00, Thu., 20 Sep. 0.0491 0.0410 0.0449
15:01-16:00, Thu., 20 Sep. 0.0444 0.0387 0.0418
14:01-15:00, Thu., 20 Sep. 0.0398 0.0328 0.0364
13:01-14:00, Thu., 20 Sep. 0.0368 0.0320 0.0350
12:01-13:00, Thu., 20 Sep. 0.0373 0.0323 0.0350
11:01-12:00, Thu., 20 Sep. 0.0371 0.0332 0.0350
10:01-11:00, Thu., 20 Sep. 0.0380 0.0323 0.0354
09:01-10:00, Thu., 20 Sep. 0.0364 0.0325 0.0345
08:01-09:00, Thu., 20 Sep. 0.0375 0.0333 0.0351
07:01-08:00, Thu., 20 Sep. 0.0368 0.0330 0.0349
06:01-07:00, Thu., 20 Sep. 0.0373 0.0323 0.0349
05:01-06:00, Thu., 20 Sep. 0.0373 0.0334 0.0351
04:01-05:00, Thu., 20 Sep. 0.0373 0.0331 0.0351
03:01-04:00, Thu., 20 Sep. 0.0363 0.0325 0.0348
02:01-03:00, Thu., 20 Sep. 0.0371 0.0323 0.0349
01:01-02:00, Thu., 20 Sep. 0.0369 0.0320 0.0348
00:01-01:00, Thu., 20 Sep. 0.0371 0.0327 0.0347
23:01-24:00, Wed., 19 Sep. 0.0360 0.0321 0.0344
22:01-23:00, Wed., 19 Sep. 0.0369 0.0322 0.0347
21:01-22:00, Wed., 19 Sep. 0.0371 0.0333 0.0348
20:01-21:00, Wed., 19 Sep. 0.0373 0.0330 0.0348
19:01-20:00, Wed., 19 Sep. 0.0375 0.0329 0.0352
18:01-19:00, Wed., 19 Sep. 0.0369 0.0325 0.0347
17:01-18:00, Wed., 19 Sep. 0.0364 0.0321 0.0349
16:01-17:00, Wed., 19 Sep. 0.0371 0.0327 0.0348
15:01-16:00, Wed., 19 Sep. 0.0371 0.0325 0.0348
14:01-15:00, Wed., 19 Sep. 0.0369 0.0326 0.0349
13:01-14:00, Wed., 19 Sep. 0.0366 0.0324 0.0345
12:01-13:00, Wed., 19 Sep. 0.0366 0.0330 0.0348
11:01-12:00, Wed., 19 Sep. 0.0370 0.0327 0.0347
10:01-11:00, Wed., 19 Sep. 0.0374 0.0325 0.0348
09:01-10:00, Wed., 19 Sep. 0.0362 0.0330 0.0348
08:01-09:00, Wed., 19 Sep. 0.0371 0.0315 0.0349
07:01-08:00, Wed., 19 Sep. 0.0372 0.0328 0.0347
06:01-07:00, Wed., 19 Sep. 0.0374 0.0331 0.0351
05:01-06:00, Wed., 19 Sep. 0.0371 0.0319 0.0349
04:01-05:00, Wed., 19 Sep. 0.0364 0.0330 0.0349
03:01-04:00, Wed., 19 Sep. 0.0375 0.0336 0.0350
02:01-03:00, Wed., 19 Sep. 0.0368 0.0328 0.0351
01:01-02:00, Wed., 19 Sep. 0.0388 0.0341 0.0363
00:01-01:00, Wed., 19 Sep. 0.0426 0.0371 0.0398
23:01-24:00, Tue., 18 Sep. 0.0423 0.0322 0.0373
22:01-23:00, Tue., 18 Sep. 0.0402 0.0354 0.0379
21:01-22:00, Tue., 18 Sep. 0.0464 0.0386 0.0419
20:01-21:00, Tue., 18 Sep. 0.0511 0.0441 0.0474
19:01-20:00, Tue., 18 Sep. 0.0533 0.0463 0.0504
18:01-19:00, Tue., 18 Sep. 0.0512 0.0331 0.0425
17:01-18:00, Tue., 18 Sep. 0.0370 0.0326 0.0349
16:01-17:00, Tue., 18 Sep. 0.0366 0.0326 0.0345
15:01-16:00, Tue., 18 Sep. 0.0369 0.0329 0.0349
14:01-15:00, Tue., 18 Sep. 0.0374 0.0320 0.0344
13:01-14:00, Tue., 18 Sep. 0.0369 0.0321 0.0347
12:01-13:00, Tue., 18 Sep. 0.0361 0.0327 0.0346
11:01-12:00, Tue., 18 Sep. 0.0378 0.0323 0.0346
10:01-11:00, Tue., 18 Sep. 0.0367 0.0325 0.0345
09:01-10:00, Tue., 18 Sep. 0.0362 0.0325 0.0346
08:01-09:00, Tue., 18 Sep. 0.0369 0.0331 0.0349
07:01-08:00, Tue., 18 Sep. 0.0365 0.0334 0.0348
06:01-07:00, Tue., 18 Sep. 0.0368 0.0327 0.0346
05:01-06:00, Tue., 18 Sep. 0.0381 0.0325 0.0350
04:01-05:00, Tue., 18 Sep. 0.0378 0.0342 0.0356
03:01-04:00, Tue., 18 Sep. 0.0376 0.0329 0.0352
02:01-03:00, Tue., 18 Sep. 0.0366 0.0326 0.0346
01:01-02:00, Tue., 18 Sep. 0.0372 0.0328 0.0352
00:01-01:00, Tue., 18 Sep. 0.0378 0.0338 0.0358
23:01-24:00, Mon., 17 Sep. 0.0384 0.0338 0.0362
22:01-23:00, Mon., 17 Sep. 0.0430 0.0359 0.0394
21:01-22:00, Mon., 17 Sep. 0.0547 0.0420 0.0478
20:01-21:00, Mon., 17 Sep. 0.0604 0.0500 0.0560
19:01-20:00, Mon., 17 Sep. 0.0602 0.0523 0.0564
18:01-19:00, Mon., 17 Sep. 0.0571 0.0370 0.0464
17:01-18:00, Mon., 17 Sep. 0.0397 0.0336 0.0359
16:01-17:00, Mon., 17 Sep. 0.0369 0.0331 0.0351
15:01-16:00, Mon., 17 Sep. 0.0373 0.0328 0.0349
14:01-15:00, Mon., 17 Sep. 0.0377 0.0321 0.0348
13:01-14:00, Mon., 17 Sep. 0.0366 0.0330 0.0347
12:01-13:00, Mon., 17 Sep. 0.0373 0.0323 0.0349
11:01-12:00, Mon., 17 Sep. 0.0369 0.0329 0.0348
10:01-11:00, Mon., 17 Sep. 0.0374 0.0329 0.0351
09:01-10:00, Mon., 17 Sep. 0.0374 0.0328 0.0349
08:01-09:00, Mon., 17 Sep. 0.0379 0.0329 0.0350
07:01-08:00, Mon., 17 Sep. 0.0366 0.0333 0.0350
06:01-07:00, Mon., 17 Sep. 0.0376 0.0330 0.0350
05:01-06:00, Mon., 17 Sep. 0.0365 0.0328 0.0350
04:01-05:00, Mon., 17 Sep. 0.0378 0.0332 0.0350
03:01-04:00, Mon., 17 Sep. 0.0366 0.0334 0.0350
02:01-03:00, Mon., 17 Sep. 0.0378 0.0330 0.0349
01:01-02:00, Mon., 17 Sep. 0.0373 0.0328 0.0350
00:01-01:00, Mon., 17 Sep. 0.0369 0.0335 0.0351
23:01-24:00, Sun., 16 Sep. 0.0372 0.0331 0.0350
22:01-23:00, Sun., 16 Sep. 0.0371 0.0325 0.0349
21:01-22:00, Sun., 16 Sep. 0.0370 0.0327 0.0349
20:01-21:00, Sun., 16 Sep. 0.0378 0.0324 0.0350
19:01-20:00, Sun., 16 Sep. 0.0370 0.0323 0.0347
18:01-19:00, Sun., 16 Sep. 0.0369 0.0324 0.0349
17:01-18:00, Sun., 16 Sep. 0.0369 0.0324 0.0348
16:01-17:00, Sun., 16 Sep. 0.0364 0.0328 0.0346
15:01-16:00, Sun., 16 Sep. 0.0378 0.0329 0.0348
14:01-15:00, Sun., 16 Sep. 0.0365 0.0326 0.0347
13:01-14:00, Sun., 16 Sep. 0.0368 0.0329 0.0347
12:01-13:00, Sun., 16 Sep. 0.0368 0.0322 0.0347
11:01-12:00, Sun., 16 Sep. 0.0361 0.0329 0.0344
10:01-11:00, Sun., 16 Sep. 0.0369 0.0319 0.0347
09:01-10:00, Sun., 16 Sep. 0.0374 0.0327 0.0347
08:01-09:00, Sun., 16 Sep. 0.0381 0.0321 0.0349
07:01-08:00, Sun., 16 Sep. 0.0375 0.0327 0.0349
06:01-07:00, Sun., 16 Sep. 0.0372 0.0324 0.0349
05:01-06:00, Sun., 16 Sep. 0.0373 0.0323 0.0349
04:01-05:00, Sun., 16 Sep. 0.0366 0.0331 0.0348
03:01-04:00, Sun., 16 Sep. 0.0373 0.0329 0.0349
02:01-03:00, Sun., 16 Sep. 0.0374 0.0328 0.0348
01:01-02:00, Sun., 16 Sep. 0.0367 0.0331 0.0346
00:01-01:00, Sun., 16 Sep. 0.0366 0.0318 0.0346
23:01-24:00, Sat., 15 Sep. 0.0366 0.0322 0.0345
22:01-23:00, Sat., 15 Sep. 0.0361 0.0325 0.0345
21:01-22:00, Sat., 15 Sep. 0.0365 0.0329 0.0344
20:01-21:00, Sat., 15 Sep. 0.0373 0.0321 0.0344
19:01-20:00, Sat., 15 Sep. 0.0363 0.0322 0.0344
18:01-19:00, Sat., 15 Sep. 0.0370 0.0325 0.0346
17:01-18:00, Sat., 15 Sep. 0.0368 0.0324 0.0346
16:01-17:00, Sat., 15 Sep. 0.0371 0.0326 0.0346
15:01-16:00, Sat., 15 Sep. 0.0364 0.0325 0.0347
14:01-15:00, Sat., 15 Sep. 0.0377 0.0336 0.0355
13:01-14:00, Sat., 15 Sep. 0.0383 0.0339 0.0363
12:01-13:00, Sat., 15 Sep. 0.0389 0.0344 0.0367
11:01-12:00, Sat., 15 Sep. 0.0387 0.0348 0.0369
10:01-11:00, Sat., 15 Sep. 0.0390 0.0348 0.0369
09:01-10:00, Sat., 15 Sep. 0.0391 0.0344 0.0372
08:01-09:00, Sat., 15 Sep. 0.0396 0.0352 0.0375
07:01-08:00, Sat., 15 Sep. 0.0381 0.0328 0.0353
06:01-07:00, Sat., 15 Sep. 0.0363 0.0316 0.0345
05:01-06:00, Sat., 15 Sep. 0.0361 0.0328 0.0345
04:01-05:00, Sat., 15 Sep. 0.0374 0.0327 0.0349
03:01-04:00, Sat., 15 Sep. 0.0373 0.0330 0.0351
02:01-03:00, Sat., 15 Sep. 0.0391 0.0340 0.0361
01:01-02:00, Sat., 15 Sep. 0.0383 0.0341 0.0364
00:01-01:00, Sat., 15 Sep. 0.0394 0.0341 0.0358
23:01-24:00, Fri., 14 Sep. 0.0379 0.0332 0.0355
22:01-23:00, Fri., 14 Sep. 0.0381 0.0341 0.0361
21:01-22:00, Fri., 14 Sep. 0.0381 0.0329 0.0357
20:01-21:00, Fri., 14 Sep. 0.0373 0.0320 0.0349
19:01-20:00, Fri., 14 Sep. 0.0371 0.0325 0.0347
18:01-19:00, Fri., 14 Sep. 0.0364 0.0326 0.0345
17:01-18:00, Fri., 14 Sep. 0.0365 0.0326 0.0345
16:01-17:00, Fri., 14 Sep. 0.0360 0.0328 0.0342
15:01-16:00, Fri., 14 Sep. 0.0367 0.0325 0.0345
14:01-15:00, Fri., 14 Sep. 0.0358 0.0326 0.0344
13:01-14:00, Fri., 14 Sep. 0.0365 0.0325 0.0343
12:01-13:00, Fri., 14 Sep. 0.0373 0.0331 0.0348
11:01-12:00, Fri., 14 Sep. 0.0366 0.0321 0.0348
10:01-11:00, Fri., 14 Sep. 0.0371 0.0324 0.0350
09:01-10:00, Fri., 14 Sep. 0.0389 0.0335 0.0355
08:01-09:00, Fri., 14 Sep. 0.0389 0.0341 0.0365
07:01-08:00, Fri., 14 Sep. 0.0384 0.0344 0.0364
06:01-07:00, Fri., 14 Sep. 0.0383 0.0341 0.0358
05:01-06:00, Fri., 14 Sep. 0.0377 0.0329 0.0354
04:01-05:00, Fri., 14 Sep. 0.0389 0.0323 0.0353
03:01-04:00, Fri., 14 Sep. 0.0375 0.0328 0.0353
02:01-03:00, Fri., 14 Sep. 0.0380 0.0331 0.0355
01:01-02:00, Fri., 14 Sep. 0.0377 0.0331 0.0354
00:01-01:00, Fri., 14 Sep. 0.0380 0.0333 0.0355
23:01-24:00, Thu., 13 Sep. 0.0377 0.0322 0.0354
22:01-23:00, Thu., 13 Sep. 0.0374 0.0329 0.0354
21:01-22:00, Thu., 13 Sep. 0.0380 0.0329 0.0355
20:01-21:00, Thu., 13 Sep. 0.0385 0.0329 0.0360
19:01-20:00, Thu., 13 Sep. 0.0370 0.0335 0.0354
18:01-19:00, Thu., 13 Sep. 0.0369 0.0329 0.0346
17:01-18:00, Thu., 13 Sep. 0.0373 0.0316 0.0346
16:01-17:00, Thu., 13 Sep. 0.0364 0.0328 0.0347
15:01-16:00, Thu., 13 Sep. 0.0384 0.0329 0.0347
14:01-15:00, Thu., 13 Sep. 0.0371 0.0329 0.0346
13:01-14:00, Thu., 13 Sep. 0.0366 0.0325 0.0347
12:01-13:00, Thu., 13 Sep. 0.0378 0.0326 0.0348
11:01-12:00, Thu., 13 Sep. 0.0367 0.0325 0.0347
10:01-11:00, Thu., 13 Sep. 0.0369 0.0329 0.0348
09:01-10:00, Thu., 13 Sep. 0.0371 0.0333 0.0350
08:01-09:00, Thu., 13 Sep. 0.0369 0.0329 0.0349
07:01-08:00, Thu., 13 Sep. 0.0380 0.0331 0.0349
06:01-07:00, Thu., 13 Sep. 0.0375 0.0335 0.0350
05:01-06:00, Thu., 13 Sep. 0.0370 0.0324 0.0350
04:01-05:00, Thu., 13 Sep. 0.0365 0.0329 0.0348
03:01-04:00, Thu., 13 Sep. 0.0368 0.0322 0.0348
02:01-03:00, Thu., 13 Sep. 0.0375 0.0330 0.0347
01:01-02:00, Thu., 13 Sep. 0.0369 0.0330 0.0348
00:01-01:00, Thu., 13 Sep. 0.0371 0.0335 0.0353
23:01-24:00, Wed., 12 Sep. 0.0367 0.0330 0.0349
22:01-23:00, Wed., 12 Sep. 0.0370 0.0334 0.0349
21:01-22:00, Wed., 12 Sep. 0.0376 0.0331 0.0353
20:01-21:00, Wed., 12 Sep. 0.0366 0.0324 0.0348
19:01-20:00, Wed., 12 Sep. 0.0374 0.0325 0.0349
18:01-19:00, Wed., 12 Sep. 0.0372 0.0325 0.0347
17:01-18:00, Wed., 12 Sep. 0.0368 0.0329 0.0346
16:01-17:00, Wed., 12 Sep. 0.0380 0.0328 0.0345
15:01-16:00, Wed., 12 Sep. 0.0368 0.0325 0.0347
14:01-15:00, Wed., 12 Sep. 0.0375 0.0328 0.0347
13:01-14:00, Wed., 12 Sep. 0.0366 0.0315 0.0344
12:01-13:00, Wed., 12 Sep. 0.0369 0.0324 0.0345
11:01-12:00, Wed., 12 Sep. 0.0371 0.0330 0.0347
10:01-11:00, Wed., 12 Sep. 0.0373 0.0322 0.0347
09:01-10:00, Wed., 12 Sep. 0.0366 0.0322 0.0345
08:01-09:00, Wed., 12 Sep. 0.0369 0.0326 0.0346
07:01-08:00, Wed., 12 Sep. 0.0369 0.0323 0.0349
06:01-07:00, Wed., 12 Sep. 0.0387 0.0333 0.0351
05:01-06:00, Wed., 12 Sep. 0.0369 0.0327 0.0346
04:01-05:00, Wed., 12 Sep. 0.0376 0.0325 0.0345
03:01-04:00, Wed., 12 Sep. 0.0365 0.0327 0.0347
02:01-03:00, Wed., 12 Sep. 0.0369 0.0328 0.0346
01:01-02:00, Wed., 12 Sep. 0.0362 0.0319 0.0344
00:01-01:00, Wed., 12 Sep. 0.0371 0.0324 0.0347
23:01-24:00, Tue., 11 Sep. 0.0362 0.0323 0.0344
22:01-23:00, Tue., 11 Sep. 0.0367 0.0323 0.0345
21:01-22:00, Tue., 11 Sep. 0.0371 0.0321 0.0348
20:01-21:00, Tue., 11 Sep. 0.0365 0.0328 0.0346
19:01-20:00, Tue., 11 Sep. 0.0364 0.0325 0.0345
18:01-19:00, Tue., 11 Sep. 0.0364 0.0326 0.0344
17:01-18:00, Tue., 11 Sep. 0.0366 0.0324 0.0345
16:01-17:00, Tue., 11 Sep. 0.0378 0.0317 0.0345
15:01-16:00, Tue., 11 Sep. 0.0363 0.0321 0.0345
14:01-15:00, Tue., 11 Sep. 0.0367 0.0321 0.0345
13:01-14:00, Tue., 11 Sep. 0.0368 0.0330 0.0347
12:01-13:00, Tue., 11 Sep. 0.0363 0.0329 0.0347
11:01-12:00, Tue., 11 Sep. 0.0368 0.0327 0.0347
10:01-11:00, Tue., 11 Sep. 0.0373 0.0322 0.0346
09:01-10:00, Tue., 11 Sep. 0.0364 0.0314 0.0344
08:01-09:00, Tue., 11 Sep. 0.0366 0.0323 0.0347
07:01-08:00, Tue., 11 Sep. 0.0365 0.0330 0.0347
06:01-07:00, Tue., 11 Sep. 0.0363 0.0332 0.0348
05:01-06:00, Tue., 11 Sep. 0.0368 0.0332 0.0347
04:01-05:00, Tue., 11 Sep. 0.0368 0.0329 0.0349
03:01-04:00, Tue., 11 Sep. 0.0387 0.0335 0.0355
02:01-03:00, Tue., 11 Sep. 0.0393 0.0341 0.0371
01:01-02:00, Tue., 11 Sep. 0.0393 0.0353 0.0375
00:01-01:00, Tue., 11 Sep. 0.0384 0.0341 0.0358
23:01-24:00, Mon., 10 Sep. 0.0382 0.0336 0.0359
22:01-23:00, Mon., 10 Sep. 0.0392 0.0353 0.0368