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, October 24,2017 Hachioji
From 13:00 to 16:00 on Tuesday, October 24,2017 Adachi
From 10:00 to 13:00 on Wednesday, October 25,2017 Chofu
From 13:00 to 16:00 on Wednesday, October 25,2017 Ota
From 10:00 to 13:00 on Thursday, October 26,2017 Kodaira
From 13:00 to 16:00 on Thursday, October 26,2017 Edogawa
From 10:00 to 13:00 on Friday, October 27,2017 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 8:00 to 19:00 on Saturday, October 28,2017






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
11:01-12:00, Tue., 17 Oct. 0.0409 0.0359 0.0380
10:01-11:00, Tue., 17 Oct. 0.0403 0.0353 0.0378
09:01-10:00, Tue., 17 Oct. 0.0394 0.0349 0.0371
08:01-09:00, Tue., 17 Oct. 0.0405 0.0358 0.0379
07:01-08:00, Tue., 17 Oct. 0.0407 0.0361 0.0382
06:01-07:00, Tue., 17 Oct. 0.0417 0.0367 0.0393
05:01-06:00, Tue., 17 Oct. 0.0413 0.0356 0.0388
04:01-05:00, Tue., 17 Oct. 0.0403 0.0353 0.0376
03:01-04:00, Tue., 17 Oct. 0.0416 0.0362 0.0392
02:01-03:00, Tue., 17 Oct. 0.0409 0.0359 0.0385
01:01-02:00, Tue., 17 Oct. 0.0409 0.0360 0.0385
00:01-01:00, Tue., 17 Oct. 0.0420 0.0355 0.0382
23:01-24:00, Mon., 16 Oct. 0.0406 0.0354 0.0380
22:01-23:00, Mon., 16 Oct. 0.0422 0.0360 0.0387
21:01-22:00, Mon., 16 Oct. 0.0409 0.0357 0.0383
20:01-21:00, Mon., 16 Oct. 0.0404 0.0358 0.0379
19:01-20:00, Mon., 16 Oct. 0.0432 0.0373 0.0398
18:01-19:00, Mon., 16 Oct. 0.0464 0.0407 0.0433
17:01-18:00, Mon., 16 Oct. 0.0464 0.0416 0.0439
16:01-17:00, Mon., 16 Oct. 0.0476 0.0417 0.0444
15:01-16:00, Mon., 16 Oct. 0.0468 0.0395 0.0435
14:01-15:00, Mon., 16 Oct. 0.0465 0.0421 0.0444
13:01-14:00, Mon., 16 Oct. 0.0472 0.0422 0.0449
12:01-13:00, Mon., 16 Oct. 0.0481 0.0374 0.0413
11:01-12:00, Mon., 16 Oct. 0.0423 0.0376 0.0397
10:01-11:00, Mon., 16 Oct. 0.0424 0.0367 0.0392
09:01-10:00, Mon., 16 Oct. 0.0424 0.0369 0.0399
08:01-09:00, Mon., 16 Oct. 0.0444 0.0383 0.0406
07:01-08:00, Mon., 16 Oct. 0.0424 0.0378 0.0407
06:01-07:00, Mon., 16 Oct. 0.0431 0.0395 0.0417
05:01-06:00, Mon., 16 Oct. 0.0457 0.0397 0.0424
04:01-05:00, Mon., 16 Oct. 0.0434 0.0393 0.0415
03:01-04:00, Mon., 16 Oct. 0.0445 0.0402 0.0424
02:01-03:00, Mon., 16 Oct. 0.0441 0.0384 0.0410
01:01-02:00, Mon., 16 Oct. 0.0440 0.0373 0.0403
00:01-01:00, Mon., 16 Oct. 0.0417 0.0374 0.0393
23:01-24:00, Sun., 15 Oct. 0.0420 0.0372 0.0398
22:01-23:00, Sun., 15 Oct. 0.0417 0.0351 0.0387
21:01-22:00, Sun., 15 Oct. 0.0395 0.0344 0.0369
20:01-21:00, Sun., 15 Oct. 0.0392 0.0336 0.0365
19:01-20:00, Sun., 15 Oct. 0.0380 0.0338 0.0363
18:01-19:00, Sun., 15 Oct. 0.0389 0.0347 0.0369
17:01-18:00, Sun., 15 Oct. 0.0394 0.0345 0.0373
16:01-17:00, Sun., 15 Oct. 0.0398 0.0343 0.0372
15:01-16:00, Sun., 15 Oct. 0.0390 0.0346 0.0370
14:01-15:00, Sun., 15 Oct. 0.0404 0.0348 0.0370
13:01-14:00, Sun., 15 Oct. 0.0397 0.0343 0.0374
12:01-13:00, Sun., 15 Oct. 0.0404 0.0360 0.0379
11:01-12:00, Sun., 15 Oct. 0.0407 0.0353 0.0374
10:01-11:00, Sun., 15 Oct. 0.0394 0.0345 0.0369
09:01-10:00, Sun., 15 Oct. 0.0398 0.0347 0.0376
08:01-09:00, Sun., 15 Oct. 0.0407 0.0361 0.0385
07:01-08:00, Sun., 15 Oct. 0.0411 0.0354 0.0380
06:01-07:00, Sun., 15 Oct. 0.0397 0.0347 0.0367
05:01-06:00, Sun., 15 Oct. 0.0379 0.0334 0.0361
04:01-05:00, Sun., 15 Oct. 0.0390 0.0343 0.0362
03:01-04:00, Sun., 15 Oct. 0.0386 0.0334 0.0358
02:01-03:00, Sun., 15 Oct. 0.0389 0.0338 0.0361
01:01-02:00, Sun., 15 Oct. 0.0387 0.0340 0.0360
00:01-01:00, Sun., 15 Oct. 0.0395 0.0335 0.0359
23:01-24:00, Sat., 14 Oct. 0.0382 0.0340 0.0360
22:01-23:00, Sat., 14 Oct. 0.0377 0.0339 0.0360
21:01-22:00, Sat., 14 Oct. 0.0382 0.0343 0.0361
20:01-21:00, Sat., 14 Oct. 0.0396 0.0335 0.0365
19:01-20:00, Sat., 14 Oct. 0.0402 0.0337 0.0370
18:01-19:00, Sat., 14 Oct. 0.0402 0.0354 0.0375
17:01-18:00, Sat., 14 Oct. 0.0386 0.0342 0.0366
16:01-17:00, Sat., 14 Oct. 0.0385 0.0338 0.0362
15:01-16:00, Sat., 14 Oct. 0.0381 0.0337 0.0360
14:01-15:00, Sat., 14 Oct. 0.0382 0.0341 0.0361
13:01-14:00, Sat., 14 Oct. 0.0381 0.0340 0.0362
12:01-13:00, Sat., 14 Oct. 0.0386 0.0342 0.0361
11:01-12:00, Sat., 14 Oct. 0.0390 0.0335 0.0359
10:01-11:00, Sat., 14 Oct. 0.0384 0.0335 0.0361
09:01-10:00, Sat., 14 Oct. 0.0392 0.0342 0.0366
08:01-09:00, Sat., 14 Oct. 0.0398 0.0352 0.0377
07:01-08:00, Sat., 14 Oct. 0.0405 0.0356 0.0378
06:01-07:00, Sat., 14 Oct. 0.0420 0.0358 0.0383
05:01-06:00, Sat., 14 Oct. 0.0441 0.0388 0.0416
04:01-05:00, Sat., 14 Oct. 0.0448 0.0390 0.0414
03:01-04:00, Sat., 14 Oct. 0.0463 0.0401 0.0430
02:01-03:00, Sat., 14 Oct. 0.0457 0.0400 0.0422
01:01-02:00, Sat., 14 Oct. 0.0452 0.0394 0.0427
00:01-01:00, Sat., 14 Oct. 0.0435 0.0347 0.0392
23:01-24:00, Fri., 13 Oct. 0.0386 0.0343 0.0366
22:01-23:00, Fri., 13 Oct. 0.0378 0.0339 0.0361
21:01-22:00, Fri., 13 Oct. 0.0384 0.0340 0.0365
20:01-21:00, Fri., 13 Oct. 0.0398 0.0348 0.0373
19:01-20:00, Fri., 13 Oct. 0.0411 0.0346 0.0381
18:01-19:00, Fri., 13 Oct. 0.0449 0.0374 0.0413
17:01-18:00, Fri., 13 Oct. 0.0461 0.0390 0.0426
16:01-17:00, Fri., 13 Oct. 0.0409 0.0361 0.0381
15:01-16:00, Fri., 13 Oct. 0.0403 0.0356 0.0376
14:01-15:00, Fri., 13 Oct. 0.0399 0.0358 0.0377
13:01-14:00, Fri., 13 Oct. 0.0418 0.0375 0.0395
12:01-13:00, Fri., 13 Oct. 0.0406 0.0354 0.0382
11:01-12:00, Fri., 13 Oct. 0.0414 0.0360 0.0387
10:01-11:00, Fri., 13 Oct. 0.0420 0.0361 0.0391
09:01-10:00, Fri., 13 Oct. 0.0411 0.0365 0.0387
08:01-09:00, Fri., 13 Oct. 0.0411 0.0365 0.0386
07:01-08:00, Fri., 13 Oct. 0.0394 0.0350 0.0370
06:01-07:00, Fri., 13 Oct. 0.0387 0.0343 0.0365
05:01-06:00, Fri., 13 Oct. 0.0389 0.0337 0.0360
04:01-05:00, Fri., 13 Oct. 0.0383 0.0342 0.0363
03:01-04:00, Fri., 13 Oct. 0.0383 0.0333 0.0361
02:01-03:00, Fri., 13 Oct. 0.0388 0.0337 0.0362
01:01-02:00, Fri., 13 Oct. 0.0380 0.0345 0.0361
00:01-01:00, Fri., 13 Oct. 0.0377 0.0334 0.0360
23:01-24:00, Thu., 12 Oct. 0.0383 0.0326 0.0359
22:01-23:00, Thu., 12 Oct. 0.0390 0.0342 0.0362
21:01-22:00, Thu., 12 Oct. 0.0382 0.0337 0.0361
20:01-21:00, Thu., 12 Oct. 0.0386 0.0337 0.0363
19:01-20:00, Thu., 12 Oct. 0.0387 0.0343 0.0364
18:01-19:00, Thu., 12 Oct. 0.0383 0.0342 0.0361
17:01-18:00, Thu., 12 Oct. 0.0389 0.0344 0.0363
16:01-17:00, Thu., 12 Oct. 0.0387 0.0345 0.0365
15:01-16:00, Thu., 12 Oct. 0.0389 0.0346 0.0365
14:01-15:00, Thu., 12 Oct. 0.0388 0.0334 0.0362
13:01-14:00, Thu., 12 Oct. 0.0378 0.0330 0.0361
12:01-13:00, Thu., 12 Oct. 0.0395 0.0338 0.0362
11:01-12:00, Thu., 12 Oct. 0.0389 0.0342 0.0362
10:01-11:00, Thu., 12 Oct. 0.0387 0.0344 0.0362
09:01-10:00, Thu., 12 Oct. 0.0390 0.0342 0.0360
08:01-09:00, Thu., 12 Oct. 0.0381 0.0337 0.0360
07:01-08:00, Thu., 12 Oct. 0.0376 0.0320 0.0360
06:01-07:00, Thu., 12 Oct. 0.0386 0.0338 0.0363
05:01-06:00, Thu., 12 Oct. 0.0384 0.0338 0.0362
04:01-05:00, Thu., 12 Oct. 0.0386 0.0335 0.0362
03:01-04:00, Thu., 12 Oct. 0.0384 0.0345 0.0362
02:01-03:00, Thu., 12 Oct. 0.0381 0.0337 0.0359
01:01-02:00, Thu., 12 Oct. 0.0379 0.0343 0.0361
00:01-01:00, Thu., 12 Oct. 0.0379 0.0331 0.0357
23:01-24:00, Wed., 11 Oct. 0.0387 0.0339 0.0361
22:01-23:00, Wed., 11 Oct. 0.0390 0.0342 0.0361
21:01-22:00, Wed., 11 Oct. 0.0386 0.0335 0.0361
20:01-21:00, Wed., 11 Oct. 0.0380 0.0338 0.0357
19:01-20:00, Wed., 11 Oct. 0.0378 0.0334 0.0358
18:01-19:00, Wed., 11 Oct. 0.0384 0.0337 0.0359
17:01-18:00, Wed., 11 Oct. 0.0377 0.0334 0.0360
16:01-17:00, Wed., 11 Oct. 0.0396 0.0336 0.0359
15:01-16:00, Wed., 11 Oct. 0.0384 0.0343 0.0363
14:01-15:00, Wed., 11 Oct. 0.0381 0.0338 0.0360
13:01-14:00, Wed., 11 Oct. 0.0381 0.0334 0.0360
12:01-13:00, Wed., 11 Oct. 0.0385 0.0338 0.0360
11:01-12:00, Wed., 11 Oct. 0.0382 0.0339 0.0361
10:01-11:00, Wed., 11 Oct. 0.0382 0.0338 0.0363
09:01-10:00, Wed., 11 Oct. 0.0385 0.0324 0.0362
08:01-09:00, Wed., 11 Oct. 0.0401 0.0340 0.0364
07:01-08:00, Wed., 11 Oct. 0.0384 0.0341 0.0363
06:01-07:00, Wed., 11 Oct. 0.0399 0.0349 0.0364
05:01-06:00, Wed., 11 Oct. 0.0392 0.0345 0.0365
04:01-05:00, Wed., 11 Oct. 0.0381 0.0343 0.0361
03:01-04:00, Wed., 11 Oct. 0.0385 0.0337 0.0362
02:01-03:00, Wed., 11 Oct. 0.0381 0.0343 0.0363
01:01-02:00, Wed., 11 Oct. 0.0381 0.0337 0.0361
00:01-01:00, Wed., 11 Oct. 0.0398 0.0345 0.0363
23:01-24:00, Tue., 10 Oct. 0.0386 0.0337 0.0359
22:01-23:00, Tue., 10 Oct. 0.0380 0.0340 0.0359
21:01-22:00, Tue., 10 Oct. 0.0384 0.0342 0.0360
20:01-21:00, Tue., 10 Oct. 0.0387 0.0336 0.0360
19:01-20:00, Tue., 10 Oct. 0.0381 0.0331 0.0362
18:01-19:00, Tue., 10 Oct. 0.0378 0.0338 0.0358
17:01-18:00, Tue., 10 Oct. 0.0381 0.0337 0.0361
16:01-17:00, Tue., 10 Oct. 0.0380 0.0335 0.0362
15:01-16:00, Tue., 10 Oct. 0.0378 0.0333 0.0359
14:01-15:00, Tue., 10 Oct. 0.0379 0.0327 0.0362
13:01-14:00, Tue., 10 Oct. 0.0387 0.0341 0.0358
12:01-13:00, Tue., 10 Oct. 0.0380 0.0335 0.0358
11:01-12:00, Tue., 10 Oct. 0.0380 0.0341 0.0361
10:01-11:00, Tue., 10 Oct. 0.0382 0.0336 0.0360
09:01-10:00, Tue., 10 Oct. 0.0390 0.0342 0.0363
08:01-09:00, Tue., 10 Oct. 0.0385 0.0339 0.0362
07:01-08:00, Tue., 10 Oct. 0.0384 0.0337 0.0362
06:01-07:00, Tue., 10 Oct. 0.0392 0.0337 0.0364
05:01-06:00, Tue., 10 Oct. 0.0385 0.0339 0.0363
04:01-05:00, Tue., 10 Oct. 0.0385 0.0345 0.0366
03:01-04:00, Tue., 10 Oct. 0.0385 0.0335 0.0361
02:01-03:00, Tue., 10 Oct. 0.0385 0.0335 0.0360
01:01-02:00, Tue., 10 Oct. 0.0383 0.0334 0.0358
00:01-01:00, Tue., 10 Oct. 0.0380 0.0333 0.0360
23:01-24:00, Mon., 09 Oct. 0.0379 0.0337 0.0358
22:01-23:00, Mon., 09 Oct. 0.0378 0.0341 0.0359
21:01-22:00, Mon., 09 Oct. 0.0378 0.0331 0.0357
20:01-21:00, Mon., 09 Oct. 0.0378 0.0329 0.0358
19:01-20:00, Mon., 09 Oct. 0.0385 0.0333 0.0357
18:01-19:00, Mon., 09 Oct. 0.0385 0.0338 0.0356
17:01-18:00, Mon., 09 Oct. 0.0385 0.0342 0.0361
16:01-17:00, Mon., 09 Oct. 0.0380 0.0333 0.0358
15:01-16:00, Mon., 09 Oct. 0.0378 0.0337 0.0360
14:01-15:00, Mon., 09 Oct. 0.0376 0.0327 0.0357
13:01-14:00, Mon., 09 Oct. 0.0380 0.0326 0.0358
12:01-13:00, Mon., 09 Oct. 0.0370 0.0334 0.0357
11:01-12:00, Mon., 09 Oct. 0.0383 0.0338 0.0358
10:01-11:00, Mon., 09 Oct. 0.0384 0.0337 0.0359
09:01-10:00, Mon., 09 Oct. 0.0374 0.0343 0.0359
08:01-09:00, Mon., 09 Oct. 0.0381 0.0334 0.0361
07:01-08:00, Mon., 09 Oct. 0.0392 0.0335 0.0360
06:01-07:00, Mon., 09 Oct. 0.0384 0.0345 0.0363
05:01-06:00, Mon., 09 Oct. 0.0381 0.0332 0.0358
04:01-05:00, Mon., 09 Oct. 0.0377 0.0342 0.0359
03:01-04:00, Mon., 09 Oct. 0.0376 0.0335 0.0356
02:01-03:00, Mon., 09 Oct. 0.0391 0.0340 0.0361
01:01-02:00, Mon., 09 Oct. 0.0378 0.0337 0.0360
00:01-01:00, Mon., 09 Oct. 0.0382 0.0342 0.0360
23:01-24:00, Sun., 08 Oct. 0.0386 0.0323 0.0358
22:01-23:00, Sun., 08 Oct. 0.0390 0.0326 0.0357
21:01-22:00, Sun., 08 Oct. 0.0376 0.0336 0.0356
20:01-21:00, Sun., 08 Oct. 0.0381 0.0336 0.0358
19:01-20:00, Sun., 08 Oct. 0.0383 0.0338 0.0361
18:01-19:00, Sun., 08 Oct. 0.0377 0.0332 0.0357
17:01-18:00, Sun., 08 Oct. 0.0379 0.0340 0.0358
16:01-17:00, Sun., 08 Oct. 0.0383 0.0329 0.0357
15:01-16:00, Sun., 08 Oct. 0.0386 0.0336 0.0358
14:01-15:00, Sun., 08 Oct. 0.0382 0.0336 0.0357
13:01-14:00, Sun., 08 Oct. 0.0378 0.0335 0.0357
12:01-13:00, Sun., 08 Oct. 0.0383 0.0329 0.0359
11:01-12:00, Sun., 08 Oct. 0.0376 0.0340 0.0358
10:01-11:00, Sun., 08 Oct. 0.0380 0.0339 0.0358
09:01-10:00, Sun., 08 Oct. 0.0387 0.0337 0.0357
08:01-09:00, Sun., 08 Oct. 0.0383 0.0339 0.0360
07:01-08:00, Sun., 08 Oct. 0.0378 0.0339 0.0360
06:01-07:00, Sun., 08 Oct. 0.0382 0.0341 0.0359
05:01-06:00, Sun., 08 Oct. 0.0384 0.0339 0.0357
04:01-05:00, Sun., 08 Oct. 0.0388 0.0333 0.0357
03:01-04:00, Sun., 08 Oct. 0.0376 0.0330 0.0358
02:01-03:00, Sun., 08 Oct. 0.0377 0.0336 0.0357
01:01-02:00, Sun., 08 Oct. 0.0379 0.0337 0.0357
00:01-01:00, Sun., 08 Oct. 0.0376 0.0329 0.0357
23:01-24:00, Sat., 07 Oct. 0.0380 0.0334 0.0357
22:01-23:00, Sat., 07 Oct. 0.0381 0.0333 0.0358
21:01-22:00, Sat., 07 Oct. 0.0374 0.0334 0.0356
20:01-21:00, Sat., 07 Oct. 0.0377 0.0339 0.0356
19:01-20:00, Sat., 07 Oct. 0.0378 0.0338 0.0355
18:01-19:00, Sat., 07 Oct. 0.0378 0.0341 0.0356
17:01-18:00, Sat., 07 Oct. 0.0381 0.0340 0.0355
16:01-17:00, Sat., 07 Oct. 0.0392 0.0340 0.0359
15:01-16:00, Sat., 07 Oct. 0.0383 0.0338 0.0360
14:01-15:00, Sat., 07 Oct. 0.0380 0.0333 0.0355
13:01-14:00, Sat., 07 Oct. 0.0384 0.0332 0.0357
12:01-13:00, Sat., 07 Oct. 0.0383 0.0345 0.0359