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, Mon., 11 Dec. 0.0382 0.0343 0.0364
10:01-11:00, Mon., 11 Dec. 0.0383 0.0342 0.0365
09:01-10:00, Mon., 11 Dec. 0.0392 0.0348 0.0365
08:01-09:00, Mon., 11 Dec. 0.0396 0.0342 0.0368
07:01-08:00, Mon., 11 Dec. 0.0386 0.0350 0.0364
06:01-07:00, Mon., 11 Dec. 0.0379 0.0339 0.0362
05:01-06:00, Mon., 11 Dec. 0.0382 0.0337 0.0362
04:01-05:00, Mon., 11 Dec. 0.0380 0.0337 0.0362
03:01-04:00, Mon., 11 Dec. 0.0389 0.0338 0.0362
02:01-03:00, Mon., 11 Dec. 0.0387 0.0339 0.0362
01:01-02:00, Mon., 11 Dec. 0.0383 0.0337 0.0361
00:01-01:00, Mon., 11 Dec. 0.0391 0.0344 0.0363
23:01-24:00, Sun., 10 Dec. 0.0381 0.0336 0.0363
22:01-23:00, Sun., 10 Dec. 0.0384 0.0342 0.0363
21:01-22:00, Sun., 10 Dec. 0.0391 0.0341 0.0364
20:01-21:00, Sun., 10 Dec. 0.0384 0.0335 0.0360
19:01-20:00, Sun., 10 Dec. 0.0381 0.0344 0.0359
18:01-19:00, Sun., 10 Dec. 0.0381 0.0344 0.0362
17:01-18:00, Sun., 10 Dec. 0.0381 0.0336 0.0361
16:01-17:00, Sun., 10 Dec. 0.0385 0.0337 0.0360
15:01-16:00, Sun., 10 Dec. 0.0384 0.0337 0.0361
14:01-15:00, Sun., 10 Dec. 0.0388 0.0336 0.0360
13:01-14:00, Sun., 10 Dec. 0.0398 0.0341 0.0365
12:01-13:00, Sun., 10 Dec. 0.0386 0.0343 0.0364
11:01-12:00, Sun., 10 Dec. 0.0393 0.0350 0.0367
10:01-11:00, Sun., 10 Dec. 0.0385 0.0343 0.0366
09:01-10:00, Sun., 10 Dec. 0.0389 0.0350 0.0369
08:01-09:00, Sun., 10 Dec. 0.0385 0.0344 0.0364
07:01-08:00, Sun., 10 Dec. 0.0392 0.0349 0.0370
06:01-07:00, Sun., 10 Dec. 0.0394 0.0342 0.0365
05:01-06:00, Sun., 10 Dec. 0.0383 0.0339 0.0367
04:01-05:00, Sun., 10 Dec. 0.0393 0.0350 0.0367
03:01-04:00, Sun., 10 Dec. 0.0379 0.0349 0.0363
02:01-03:00, Sun., 10 Dec. 0.0382 0.0343 0.0365
01:01-02:00, Sun., 10 Dec. 0.0387 0.0342 0.0362
00:01-01:00, Sun., 10 Dec. 0.0392 0.0341 0.0365
23:01-24:00, Sat., 09 Dec. 0.0380 0.0341 0.0364
22:01-23:00, Sat., 09 Dec. 0.0388 0.0340 0.0363
21:01-22:00, Sat., 09 Dec. 0.0385 0.0339 0.0362
20:01-21:00, Sat., 09 Dec. 0.0380 0.0340 0.0359
19:01-20:00, Sat., 09 Dec. 0.0385 0.0339 0.0360
18:01-19:00, Sat., 09 Dec. 0.0385 0.0343 0.0362
17:01-18:00, Sat., 09 Dec. 0.0381 0.0332 0.0359
16:01-17:00, Sat., 09 Dec. 0.0380 0.0338 0.0358
15:01-16:00, Sat., 09 Dec. 0.0376 0.0340 0.0359
14:01-15:00, Sat., 09 Dec. 0.0379 0.0337 0.0361
13:01-14:00, Sat., 09 Dec. 0.0387 0.0346 0.0361
12:01-13:00, Sat., 09 Dec. 0.0389 0.0340 0.0362
11:01-12:00, Sat., 09 Dec. 0.0386 0.0339 0.0363
10:01-11:00, Sat., 09 Dec. 0.0381 0.0338 0.0359
09:01-10:00, Sat., 09 Dec. 0.0398 0.0338 0.0361
08:01-09:00, Sat., 09 Dec. 0.0380 0.0323 0.0359
07:01-08:00, Sat., 09 Dec. 0.0387 0.0332 0.0360
06:01-07:00, Sat., 09 Dec. 0.0384 0.0344 0.0361
05:01-06:00, Sat., 09 Dec. 0.0384 0.0338 0.0362
04:01-05:00, Sat., 09 Dec. 0.0384 0.0337 0.0362
03:01-04:00, Sat., 09 Dec. 0.0386 0.0337 0.0363
02:01-03:00, Sat., 09 Dec. 0.0381 0.0344 0.0363
01:01-02:00, Sat., 09 Dec. 0.0382 0.0337 0.0362
00:01-01:00, Sat., 09 Dec. 0.0391 0.0344 0.0364
23:01-24:00, Fri., 08 Dec. 0.0395 0.0352 0.0374
22:01-23:00, Fri., 08 Dec. 0.0422 0.0368 0.0395
21:01-22:00, Fri., 08 Dec. 0.0439 0.0378 0.0410
20:01-21:00, Fri., 08 Dec. 0.0448 0.0396 0.0424
19:01-20:00, Fri., 08 Dec. 0.0433 0.0386 0.0409
18:01-19:00, Fri., 08 Dec. 0.0426 0.0364 0.0395
17:01-18:00, Fri., 08 Dec. 0.0406 0.0353 0.0379
16:01-17:00, Fri., 08 Dec. 0.0396 0.0344 0.0367
15:01-16:00, Fri., 08 Dec. 0.0389 0.0349 0.0369
14:01-15:00, Fri., 08 Dec. 0.0392 0.0345 0.0370
13:01-14:00, Fri., 08 Dec. 0.0384 0.0340 0.0365
12:01-13:00, Fri., 08 Dec. 0.0391 0.0344 0.0367
11:01-12:00, Fri., 08 Dec. 0.0394 0.0343 0.0367
10:01-11:00, Fri., 08 Dec. 0.0384 0.0344 0.0366
09:01-10:00, Fri., 08 Dec. 0.0386 0.0344 0.0364
08:01-09:00, Fri., 08 Dec. 0.0386 0.0348 0.0367
07:01-08:00, Fri., 08 Dec. 0.0393 0.0350 0.0368
06:01-07:00, Fri., 08 Dec. 0.0387 0.0351 0.0369
05:01-06:00, Fri., 08 Dec. 0.0388 0.0347 0.0368
04:01-05:00, Fri., 08 Dec. 0.0388 0.0350 0.0367
03:01-04:00, Fri., 08 Dec. 0.0386 0.0349 0.0364
02:01-03:00, Fri., 08 Dec. 0.0392 0.0341 0.0365
01:01-02:00, Fri., 08 Dec. 0.0390 0.0343 0.0361
00:01-01:00, Fri., 08 Dec. 0.0399 0.0341 0.0366
23:01-24:00, Thu., 07 Dec. 0.0388 0.0343 0.0365
22:01-23:00, Thu., 07 Dec. 0.0391 0.0340 0.0361
21:01-22:00, Thu., 07 Dec. 0.0378 0.0343 0.0360
20:01-21:00, Thu., 07 Dec. 0.0383 0.0334 0.0360
19:01-20:00, Thu., 07 Dec. 0.0382 0.0342 0.0361
18:01-19:00, Thu., 07 Dec. 0.0395 0.0339 0.0363
17:01-18:00, Thu., 07 Dec. 0.0378 0.0337 0.0361
16:01-17:00, Thu., 07 Dec. 0.0379 0.0341 0.0359
15:01-16:00, Thu., 07 Dec. 0.0389 0.0343 0.0362
14:01-15:00, Thu., 07 Dec. 0.0391 0.0346 0.0361
13:01-14:00, Thu., 07 Dec. 0.0378 0.0334 0.0360
12:01-13:00, Thu., 07 Dec. 0.0382 0.0345 0.0363
11:01-12:00, Thu., 07 Dec. 0.0392 0.0343 0.0366
10:01-11:00, Thu., 07 Dec. 0.0383 0.0349 0.0366
09:01-10:00, Thu., 07 Dec. 0.0401 0.0346 0.0366
08:01-09:00, Thu., 07 Dec. 0.0395 0.0341 0.0370
07:01-08:00, Thu., 07 Dec. 0.0390 0.0344 0.0365
06:01-07:00, Thu., 07 Dec. 0.0389 0.0347 0.0369
05:01-06:00, Thu., 07 Dec. 0.0388 0.0337 0.0364
04:01-05:00, Thu., 07 Dec. 0.0388 0.0340 0.0365
03:01-04:00, Thu., 07 Dec. 0.0384 0.0336 0.0361
02:01-03:00, Thu., 07 Dec. 0.0384 0.0339 0.0365
01:01-02:00, Thu., 07 Dec. 0.0380 0.0331 0.0360
00:01-01:00, Thu., 07 Dec. 0.0381 0.0348 0.0363
23:01-24:00, Wed., 06 Dec. 0.0384 0.0343 0.0364
22:01-23:00, Wed., 06 Dec. 0.0391 0.0336 0.0361
21:01-22:00, Wed., 06 Dec. 0.0385 0.0334 0.0362
20:01-21:00, Wed., 06 Dec. 0.0386 0.0341 0.0363
19:01-20:00, Wed., 06 Dec. 0.0380 0.0340 0.0361
18:01-19:00, Wed., 06 Dec. 0.0383 0.0336 0.0362
17:01-18:00, Wed., 06 Dec. 0.0385 0.0341 0.0363
16:01-17:00, Wed., 06 Dec. 0.0383 0.0337 0.0362
15:01-16:00, Wed., 06 Dec. 0.0380 0.0346 0.0362
14:01-15:00, Wed., 06 Dec. 0.0380 0.0342 0.0359
13:01-14:00, Wed., 06 Dec. 0.0390 0.0342 0.0361
12:01-13:00, Wed., 06 Dec. 0.0382 0.0341 0.0361
11:01-12:00, Wed., 06 Dec. 0.0381 0.0342 0.0361
10:01-11:00, Wed., 06 Dec. 0.0379 0.0331 0.0360
09:01-10:00, Wed., 06 Dec. 0.0389 0.0334 0.0363
08:01-09:00, Wed., 06 Dec. 0.0389 0.0348 0.0364
07:01-08:00, Wed., 06 Dec. 0.0391 0.0344 0.0363
06:01-07:00, Wed., 06 Dec. 0.0381 0.0343 0.0359
05:01-06:00, Wed., 06 Dec. 0.0397 0.0345 0.0364
04:01-05:00, Wed., 06 Dec. 0.0379 0.0341 0.0363
03:01-04:00, Wed., 06 Dec. 0.0381 0.0340 0.0360
02:01-03:00, Wed., 06 Dec. 0.0378 0.0334 0.0359
01:01-02:00, Wed., 06 Dec. 0.0373 0.0337 0.0357
00:01-01:00, Wed., 06 Dec. 0.0379 0.0331 0.0356
23:01-24:00, Tue., 05 Dec. 0.0381 0.0339 0.0358
22:01-23:00, Tue., 05 Dec. 0.0382 0.0334 0.0360
21:01-22:00, Tue., 05 Dec. 0.0381 0.0337 0.0362
20:01-21:00, Tue., 05 Dec. 0.0385 0.0336 0.0360
19:01-20:00, Tue., 05 Dec. 0.0375 0.0338 0.0358
18:01-19:00, Tue., 05 Dec. 0.0380 0.0342 0.0362
17:01-18:00, Tue., 05 Dec. 0.0378 0.0344 0.0359
16:01-17:00, Tue., 05 Dec. 0.0385 0.0330 0.0357
15:01-16:00, Tue., 05 Dec. 0.0384 0.0339 0.0362
14:01-15:00, Tue., 05 Dec. 0.0383 0.0341 0.0363
13:01-14:00, Tue., 05 Dec. 0.0391 0.0340 0.0364
12:01-13:00, Tue., 05 Dec. 0.0386 0.0337 0.0362
11:01-12:00, Tue., 05 Dec. 0.0391 0.0336 0.0362
10:01-11:00, Tue., 05 Dec. 0.0384 0.0345 0.0364
09:01-10:00, Tue., 05 Dec. 0.0388 0.0331 0.0361
08:01-09:00, Tue., 05 Dec. 0.0382 0.0343 0.0363
07:01-08:00, Tue., 05 Dec. 0.0382 0.0350 0.0364
06:01-07:00, Tue., 05 Dec. 0.0396 0.0342 0.0366
05:01-06:00, Tue., 05 Dec. 0.0384 0.0346 0.0365
04:01-05:00, Tue., 05 Dec. 0.0384 0.0340 0.0362
03:01-04:00, Tue., 05 Dec. 0.0391 0.0348 0.0364
02:01-03:00, Tue., 05 Dec. 0.0381 0.0345 0.0363
01:01-02:00, Tue., 05 Dec. 0.0385 0.0331 0.0361
00:01-01:00, Tue., 05 Dec. 0.0382 0.0334 0.0361
23:01-24:00, Mon., 04 Dec. 0.0381 0.0345 0.0362
22:01-23:00, Mon., 04 Dec. 0.0384 0.0339 0.0363
21:01-22:00, Mon., 04 Dec. 0.0384 0.0347 0.0365
20:01-21:00, Mon., 04 Dec. 0.0400 0.0347 0.0369
19:01-20:00, Mon., 04 Dec. 0.0397 0.0358 0.0375
18:01-19:00, Mon., 04 Dec. 0.0385 0.0344 0.0364
17:01-18:00, Mon., 04 Dec. 0.0386 0.0333 0.0360
16:01-17:00, Mon., 04 Dec. 0.0388 0.0343 0.0362
15:01-16:00, Mon., 04 Dec. 0.0379 0.0333 0.0363
14:01-15:00, Mon., 04 Dec. 0.0386 0.0337 0.0361
13:01-14:00, Mon., 04 Dec. 0.0382 0.0349 0.0363
12:01-13:00, Mon., 04 Dec. 0.0393 0.0342 0.0364
11:01-12:00, Mon., 04 Dec. 0.0386 0.0340 0.0362
10:01-11:00, Mon., 04 Dec. 0.0393 0.0341 0.0365
09:01-10:00, Mon., 04 Dec. 0.0392 0.0335 0.0363
08:01-09:00, Mon., 04 Dec. 0.0390 0.0342 0.0367
07:01-08:00, Mon., 04 Dec. 0.0390 0.0349 0.0366
06:01-07:00, Mon., 04 Dec. 0.0396 0.0348 0.0367
05:01-06:00, Mon., 04 Dec. 0.0385 0.0348 0.0364
04:01-05:00, Mon., 04 Dec. 0.0388 0.0344 0.0364
03:01-04:00, Mon., 04 Dec. 0.0386 0.0339 0.0364
02:01-03:00, Mon., 04 Dec. 0.0388 0.0330 0.0360
01:01-02:00, Mon., 04 Dec. 0.0393 0.0352 0.0365
00:01-01:00, Mon., 04 Dec. 0.0383 0.0335 0.0362
23:01-24:00, Sun., 03 Dec. 0.0382 0.0332 0.0363
22:01-23:00, Sun., 03 Dec. 0.0386 0.0344 0.0362
21:01-22:00, Sun., 03 Dec. 0.0387 0.0341 0.0362
20:01-21:00, Sun., 03 Dec. 0.0385 0.0337 0.0362
19:01-20:00, Sun., 03 Dec. 0.0381 0.0337 0.0363
18:01-19:00, Sun., 03 Dec. 0.0382 0.0343 0.0363
17:01-18:00, Sun., 03 Dec. 0.0389 0.0338 0.0360
16:01-17:00, Sun., 03 Dec. 0.0386 0.0348 0.0365
15:01-16:00, Sun., 03 Dec. 0.0390 0.0338 0.0362
14:01-15:00, Sun., 03 Dec. 0.0397 0.0340 0.0362
13:01-14:00, Sun., 03 Dec. 0.0382 0.0343 0.0360
12:01-13:00, Sun., 03 Dec. 0.0383 0.0339 0.0363
11:01-12:00, Sun., 03 Dec. 0.0380 0.0344 0.0363
10:01-11:00, Sun., 03 Dec. 0.0391 0.0342 0.0364
09:01-10:00, Sun., 03 Dec. 0.0397 0.0340 0.0362
08:01-09:00, Sun., 03 Dec. 0.0386 0.0342 0.0363
07:01-08:00, Sun., 03 Dec. 0.0385 0.0343 0.0364
06:01-07:00, Sun., 03 Dec. 0.0379 0.0345 0.0364
05:01-06:00, Sun., 03 Dec. 0.0383 0.0341 0.0364
04:01-05:00, Sun., 03 Dec. 0.0391 0.0338 0.0363
03:01-04:00, Sun., 03 Dec. 0.0378 0.0341 0.0361
02:01-03:00, Sun., 03 Dec. 0.0383 0.0335 0.0363
01:01-02:00, Sun., 03 Dec. 0.0385 0.0345 0.0363
00:01-01:00, Sun., 03 Dec. 0.0383 0.0340 0.0359
23:01-24:00, Sat., 02 Dec. 0.0387 0.0329 0.0359
22:01-23:00, Sat., 02 Dec. 0.0377 0.0331 0.0358
21:01-22:00, Sat., 02 Dec. 0.0380 0.0341 0.0361
20:01-21:00, Sat., 02 Dec. 0.0378 0.0333 0.0358
19:01-20:00, Sat., 02 Dec. 0.0389 0.0333 0.0359
18:01-19:00, Sat., 02 Dec. 0.0390 0.0330 0.0361
17:01-18:00, Sat., 02 Dec. 0.0380 0.0339 0.0358
16:01-17:00, Sat., 02 Dec. 0.0384 0.0337 0.0360
15:01-16:00, Sat., 02 Dec. 0.0381 0.0341 0.0361
14:01-15:00, Sat., 02 Dec. 0.0377 0.0340 0.0359
13:01-14:00, Sat., 02 Dec. 0.0384 0.0336 0.0360
12:01-13:00, Sat., 02 Dec. 0.0386 0.0340 0.0359
11:01-12:00, Sat., 02 Dec. 0.0378 0.0341 0.0360
10:01-11:00, Sat., 02 Dec. 0.0386 0.0337 0.0358
09:01-10:00, Sat., 02 Dec. 0.0380 0.0334 0.0360
08:01-09:00, Sat., 02 Dec. 0.0393 0.0337 0.0361
07:01-08:00, Sat., 02 Dec. 0.0374 0.0343 0.0361
06:01-07:00, Sat., 02 Dec. 0.0375 0.0331 0.0357
05:01-06:00, Sat., 02 Dec. 0.0380 0.0338 0.0360
04:01-05:00, Sat., 02 Dec. 0.0379 0.0335 0.0358
03:01-04:00, Sat., 02 Dec. 0.0381 0.0329 0.0360
02:01-03:00, Sat., 02 Dec. 0.0385 0.0338 0.0360
01:01-02:00, Sat., 02 Dec. 0.0377 0.0339 0.0360
00:01-01:00, Sat., 02 Dec. 0.0383 0.0339 0.0359
23:01-24:00, Fri., 01 Dec. 0.0393 0.0340 0.0359
22:01-23:00, Fri., 01 Dec. 0.0385 0.0341 0.0360
21:01-22:00, Fri., 01 Dec. 0.0378 0.0342 0.0359
20:01-21:00, Fri., 01 Dec. 0.0382 0.0340 0.0362
19:01-20:00, Fri., 01 Dec. 0.0389 0.0337 0.0360
18:01-19:00, Fri., 01 Dec. 0.0379 0.0339 0.0358
17:01-18:00, Fri., 01 Dec. 0.0381 0.0334 0.0358
16:01-17:00, Fri., 01 Dec. 0.0389 0.0339 0.0364
15:01-16:00, Fri., 01 Dec. 0.0383 0.0328 0.0356
14:01-15:00, Fri., 01 Dec. 0.0384 0.0330 0.0360
13:01-14:00, Fri., 01 Dec. 0.0403 0.0336 0.0367
12:01-13:00, Fri., 01 Dec. 0.0401 0.0345 0.0366