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

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 update the monitoring post from Wednesday, March 8 to Thursday, March 9, 2023. Since it is not possible to measure the radiation dose in the atmosphere during the update work, the provision of measurement results will be temporarily suspended at the following monitoring posts.

Adachi Bureau (Toneri Park) Wednesday, March 8, from around 8 a.m. to 6 p.m.
Chofu Bureau (Chofu Airfield) Thursday, March 9, from 8 a.m. to 6 p.m.


On Friday, March 10, 2023, from around 9 a.m. to around noon, maintenance and inspection of the Kodaira Bureau (Medicinal Botanical Garden) will be conducted.
Since the amount of radiation in the atmosphere cannot be measured during maintenance and inspection, the provision of measurement results is temporarily suspended.

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
15:01-16:00, Fri., 02 Jun. 0.0370 0.0317 0.0335
14:01-15:00, Fri., 02 Jun. 0.0370 0.0321 0.0340
13:01-14:00, Fri., 02 Jun. 0.0365 0.0313 0.0340
12:01-13:00, Fri., 02 Jun. 0.0356 0.0304 0.0337
11:01-12:00, Fri., 02 Jun. 0.0366 0.0311 0.0341
10:01-11:00, Fri., 02 Jun. 0.0374 0.0322 0.0344
09:01-10:00, Fri., 02 Jun. 0.0376 0.0318 0.0343
08:01-09:00, Fri., 02 Jun. 0.0368 0.0327 0.0351
07:01-08:00, Fri., 02 Jun. 0.0399 0.0337 0.0365
06:01-07:00, Fri., 02 Jun. 0.0415 0.0353 0.0385
05:01-06:00, Fri., 02 Jun. 0.0438 0.0385 0.0408
04:01-05:00, Fri., 02 Jun. 0.0462 0.0405 0.0431
03:01-04:00, Fri., 02 Jun. 0.0462 0.0377 0.0425
02:01-03:00, Fri., 02 Jun. 0.0433 0.0346 0.0391
01:01-02:00, Fri., 02 Jun. 0.0386 0.0337 0.0359
00:01-01:00, Fri., 02 Jun. 0.0387 0.0328 0.0358
23:01-24:00, Thu., 01 Jun. 0.0362 0.0302 0.0330
22:01-23:00, Thu., 01 Jun. 0.0350 0.0301 0.0324
21:01-22:00, Thu., 01 Jun. 0.0351 0.0301 0.0325
20:01-21:00, Thu., 01 Jun. 0.0344 0.0307 0.0325
19:01-20:00, Thu., 01 Jun. 0.0344 0.0299 0.0324
18:01-19:00, Thu., 01 Jun. 0.0340 0.0298 0.0321
17:01-18:00, Thu., 01 Jun. 0.0346 0.0302 0.0321
16:01-17:00, Thu., 01 Jun. 0.0352 0.0303 0.0326
15:01-16:00, Thu., 01 Jun. 0.0329 0.0290 0.0310
14:01-15:00, Thu., 01 Jun. 0.0339 0.0278 0.0310
13:01-14:00, Thu., 01 Jun. 0.0343 0.0301 0.0324
12:01-13:00, Thu., 01 Jun. 0.0349 0.0291 0.0321
11:01-12:00, Thu., 01 Jun. 0.0350 0.0302 0.0322
10:01-11:00, Thu., 01 Jun. 0.0343 0.0300 0.0323
09:01-10:00, Thu., 01 Jun. 0.0348 0.0301 0.0320
08:01-09:00, Thu., 01 Jun. 0.0352 0.0291 0.0324
07:01-08:00, Thu., 01 Jun. 0.0360 0.0304 0.0325
06:01-07:00, Thu., 01 Jun. 0.0346 0.0300 0.0324
05:01-06:00, Thu., 01 Jun. 0.0337 0.0300 0.0321
04:01-05:00, Thu., 01 Jun. 0.0339 0.0290 0.0317
03:01-04:00, Thu., 01 Jun. 0.0342 0.0304 0.0321
02:01-03:00, Thu., 01 Jun. 0.0343 0.0299 0.0322
01:01-02:00, Thu., 01 Jun. 0.0338 0.0292 0.0321
00:01-01:00, Thu., 01 Jun. 0.0340 0.0300 0.0321
23:01-24:00, Wed., 31 May. 0.0351 0.0298 0.0321
22:01-23:00, Wed., 31 May. 0.0346 0.0297 0.0321
21:01-22:00, Wed., 31 May. 0.0349 0.0305 0.0326
20:01-21:00, Wed., 31 May. 0.0346 0.0286 0.0322
19:01-20:00, Wed., 31 May. 0.0343 0.0301 0.0324
18:01-19:00, Wed., 31 May. 0.0346 0.0301 0.0324
17:01-18:00, Wed., 31 May. 0.0344 0.0312 0.0325
16:01-17:00, Wed., 31 May. 0.0340 0.0297 0.0324
15:01-16:00, Wed., 31 May. 0.0349 0.0301 0.0324
14:01-15:00, Wed., 31 May. 0.0352 0.0287 0.0324
13:01-14:00, Wed., 31 May. 0.0352 0.0302 0.0320
12:01-13:00, Wed., 31 May. 0.0349 0.0290 0.0324
11:01-12:00, Wed., 31 May. 0.0345 0.0295 0.0323
10:01-11:00, Wed., 31 May. 0.0342 0.0301 0.0323
09:01-10:00, Wed., 31 May. 0.0351 0.0299 0.0321
08:01-09:00, Wed., 31 May. 0.0350 0.0303 0.0324
07:01-08:00, Wed., 31 May. 0.0362 0.0315 0.0336
06:01-07:00, Wed., 31 May. 0.0426 0.0332 0.0373
05:01-06:00, Wed., 31 May. 0.0439 0.0356 0.0401
04:01-05:00, Wed., 31 May. 0.0379 0.0314 0.0348
03:01-04:00, Wed., 31 May. 0.0367 0.0305 0.0328
02:01-03:00, Wed., 31 May. 0.0344 0.0308 0.0327
01:01-02:00, Wed., 31 May. 0.0350 0.0305 0.0327
00:01-01:00, Wed., 31 May. 0.0349 0.0300 0.0326
23:01-24:00, Tue., 30 May. 0.0353 0.0304 0.0326
22:01-23:00, Tue., 30 May. 0.0353 0.0301 0.0325
21:01-22:00, Tue., 30 May. 0.0354 0.0306 0.0328
20:01-21:00, Tue., 30 May. 0.0344 0.0302 0.0326
19:01-20:00, Tue., 30 May. 0.0344 0.0306 0.0325
18:01-19:00, Tue., 30 May. 0.0349 0.0301 0.0325
17:01-18:00, Tue., 30 May. 0.0350 0.0297 0.0323
16:01-17:00, Tue., 30 May. 0.0350 0.0297 0.0325
15:01-16:00, Tue., 30 May. 0.0346 0.0301 0.0323
14:01-15:00, Tue., 30 May. 0.0355 0.0300 0.0327
13:01-14:00, Tue., 30 May. 0.0347 0.0302 0.0326
12:01-13:00, Tue., 30 May. 0.0348 0.0304 0.0327
11:01-12:00, Tue., 30 May. 0.0361 0.0296 0.0328
10:01-11:00, Tue., 30 May. 0.0357 0.0308 0.0330
09:01-10:00, Tue., 30 May. 0.0369 0.0304 0.0333
08:01-09:00, Tue., 30 May. 0.0363 0.0313 0.0336
07:01-08:00, Tue., 30 May. 0.0360 0.0307 0.0333
06:01-07:00, Tue., 30 May. 0.0364 0.0315 0.0337
05:01-06:00, Tue., 30 May. 0.0356 0.0309 0.0335
04:01-05:00, Tue., 30 May. 0.0370 0.0303 0.0343
03:01-04:00, Tue., 30 May. 0.0356 0.0306 0.0332
02:01-03:00, Tue., 30 May. 0.0353 0.0315 0.0332
01:01-02:00, Tue., 30 May. 0.0388 0.0329 0.0350
00:01-01:00, Tue., 30 May. 0.0400 0.0327 0.0367
23:01-24:00, Mon., 29 May. 0.0485 0.0385 0.0429
22:01-23:00, Mon., 29 May. 0.0536 0.0428 0.0483
21:01-22:00, Mon., 29 May. 0.0534 0.0475 0.0501
20:01-21:00, Mon., 29 May. 0.0544 0.0410 0.0469
19:01-20:00, Mon., 29 May. 0.0434 0.0379 0.0410
18:01-19:00, Mon., 29 May. 0.0439 0.0382 0.0404
17:01-18:00, Mon., 29 May. 0.0423 0.0365 0.0397
16:01-17:00, Mon., 29 May. 0.0438 0.0377 0.0401
15:01-16:00, Mon., 29 May. 0.0426 0.0378 0.0407
14:01-15:00, Mon., 29 May. 0.0444 0.0370 0.0411
13:01-14:00, Mon., 29 May. 0.0383 0.0328 0.0354
12:01-13:00, Mon., 29 May. 0.0374 0.0322 0.0348
11:01-12:00, Mon., 29 May. 0.0400 0.0335 0.0361
10:01-11:00, Mon., 29 May. 0.0440 0.0368 0.0404
09:01-10:00, Mon., 29 May. 0.0446 0.0387 0.0422
08:01-09:00, Mon., 29 May. 0.0469 0.0384 0.0429
07:01-08:00, Mon., 29 May. 0.0421 0.0363 0.0398
06:01-07:00, Mon., 29 May. 0.0433 0.0362 0.0408
05:01-06:00, Mon., 29 May. 0.0423 0.0377 0.0400
04:01-05:00, Mon., 29 May. 0.0449 0.0395 0.0420
03:01-04:00, Mon., 29 May. 0.0443 0.0356 0.0399
02:01-03:00, Mon., 29 May. 0.0397 0.0322 0.0352
01:01-02:00, Mon., 29 May. 0.0352 0.0305 0.0335
00:01-01:00, Mon., 29 May. 0.0370 0.0309 0.0340
23:01-24:00, Sun., 28 May. 0.0371 0.0314 0.0345
22:01-23:00, Sun., 28 May. 0.0399 0.0343 0.0372
21:01-22:00, Sun., 28 May. 0.0381 0.0317 0.0341
20:01-21:00, Sun., 28 May. 0.0358 0.0302 0.0328
19:01-20:00, Sun., 28 May. 0.0355 0.0303 0.0332
18:01-19:00, Sun., 28 May. 0.0351 0.0301 0.0322
17:01-18:00, Sun., 28 May. 0.0340 0.0301 0.0325
16:01-17:00, Sun., 28 May. 0.0343 0.0298 0.0321
15:01-16:00, Sun., 28 May. 0.0346 0.0285 0.0322
14:01-15:00, Sun., 28 May. 0.0345 0.0300 0.0322
13:01-14:00, Sun., 28 May. 0.0346 0.0302 0.0323
12:01-13:00, Sun., 28 May. 0.0343 0.0301 0.0321
11:01-12:00, Sun., 28 May. 0.0343 0.0300 0.0325
10:01-11:00, Sun., 28 May. 0.0349 0.0305 0.0326
09:01-10:00, Sun., 28 May. 0.0348 0.0303 0.0324
08:01-09:00, Sun., 28 May. 0.0346 0.0301 0.0324
07:01-08:00, Sun., 28 May. 0.0345 0.0299 0.0326
06:01-07:00, Sun., 28 May. 0.0350 0.0304 0.0325
05:01-06:00, Sun., 28 May. 0.0342 0.0297 0.0322
04:01-05:00, Sun., 28 May. 0.0349 0.0298 0.0320
03:01-04:00, Sun., 28 May. 0.0343 0.0298 0.0322
02:01-03:00, Sun., 28 May. 0.0345 0.0303 0.0320
01:01-02:00, Sun., 28 May. 0.0342 0.0301 0.0323
00:01-01:00, Sun., 28 May. 0.0353 0.0308 0.0325
23:01-24:00, Sat., 27 May. 0.0342 0.0302 0.0323
22:01-23:00, Sat., 27 May. 0.0346 0.0302 0.0324
21:01-22:00, Sat., 27 May. 0.0349 0.0299 0.0322
20:01-21:00, Sat., 27 May. 0.0346 0.0301 0.0322
19:01-20:00, Sat., 27 May. 0.0343 0.0296 0.0320
18:01-19:00, Sat., 27 May. 0.0347 0.0299 0.0318
17:01-18:00, Sat., 27 May. 0.0342 0.0299 0.0322
16:01-17:00, Sat., 27 May. 0.0339 0.0293 0.0323
15:01-16:00, Sat., 27 May. 0.0353 0.0307 0.0323
14:01-15:00, Sat., 27 May. 0.0349 0.0299 0.0322
13:01-14:00, Sat., 27 May. 0.0349 0.0301 0.0322
12:01-13:00, Sat., 27 May. 0.0344 0.0293 0.0320
11:01-12:00, Sat., 27 May. 0.0351 0.0297 0.0323
10:01-11:00, Sat., 27 May. 0.0347 0.0307 0.0322
09:01-10:00, Sat., 27 May. 0.0345 0.0302 0.0323
08:01-09:00, Sat., 27 May. 0.0345 0.0298 0.0322
07:01-08:00, Sat., 27 May. 0.0345 0.0293 0.0321
06:01-07:00, Sat., 27 May. 0.0350 0.0301 0.0324
05:01-06:00, Sat., 27 May. 0.0337 0.0298 0.0323
04:01-05:00, Sat., 27 May. 0.0339 0.0291 0.0320
03:01-04:00, Sat., 27 May. 0.0360 0.0297 0.0321
02:01-03:00, Sat., 27 May. 0.0343 0.0286 0.0317
01:01-02:00, Sat., 27 May. 0.0348 0.0294 0.0321
00:01-01:00, Sat., 27 May. 0.0344 0.0297 0.0321
23:01-24:00, Fri., 26 May. 0.0341 0.0298 0.0324
22:01-23:00, Fri., 26 May. 0.0340 0.0301 0.0323
21:01-22:00, Fri., 26 May. 0.0347 0.0301 0.0321
20:01-21:00, Fri., 26 May. 0.0343 0.0307 0.0322
19:01-20:00, Fri., 26 May. 0.0341 0.0297 0.0321
18:01-19:00, Fri., 26 May. 0.0340 0.0294 0.0319
17:01-18:00, Fri., 26 May. 0.0339 0.0283 0.0320
16:01-17:00, Fri., 26 May. 0.0343 0.0297 0.0320
15:01-16:00, Fri., 26 May. 0.0345 0.0297 0.0319
14:01-15:00, Fri., 26 May. 0.0337 0.0301 0.0320
13:01-14:00, Fri., 26 May. 0.0352 0.0305 0.0323
12:01-13:00, Fri., 26 May. 0.0346 0.0302 0.0321
11:01-12:00, Fri., 26 May. 0.0339 0.0298 0.0320
10:01-11:00, Fri., 26 May. 0.0343 0.0301 0.0320
09:01-10:00, Fri., 26 May. 0.0336 0.0296 0.0319
08:01-09:00, Fri., 26 May. 0.0346 0.0301 0.0320
07:01-08:00, Fri., 26 May. 0.0339 0.0298 0.0320
06:01-07:00, Fri., 26 May. 0.0342 0.0298 0.0320
05:01-06:00, Fri., 26 May. 0.0340 0.0303 0.0319
04:01-05:00, Fri., 26 May. 0.0345 0.0301 0.0318
03:01-04:00, Fri., 26 May. 0.0345 0.0298 0.0317
02:01-03:00, Fri., 26 May. 0.0348 0.0295 0.0318
01:01-02:00, Fri., 26 May. 0.0346 0.0301 0.0320
00:01-01:00, Fri., 26 May. 0.0338 0.0288 0.0318
23:01-24:00, Thu., 25 May. 0.0350 0.0294 0.0319
22:01-23:00, Thu., 25 May. 0.0343 0.0297 0.0319
21:01-22:00, Thu., 25 May. 0.0347 0.0300 0.0322
20:01-21:00, Thu., 25 May. 0.0340 0.0296 0.0321
19:01-20:00, Thu., 25 May. 0.0351 0.0294 0.0320
18:01-19:00, Thu., 25 May. 0.0343 0.0304 0.0321
17:01-18:00, Thu., 25 May. 0.0344 0.0294 0.0320
16:01-17:00, Thu., 25 May. 0.0343 0.0302 0.0319
15:01-16:00, Thu., 25 May. 0.0343 0.0294 0.0320
14:01-15:00, Thu., 25 May. 0.0344 0.0295 0.0320
13:01-14:00, Thu., 25 May. 0.0340 0.0302 0.0322
12:01-13:00, Thu., 25 May. 0.0355 0.0301 0.0325
11:01-12:00, Thu., 25 May. 0.0346 0.0299 0.0321
10:01-11:00, Thu., 25 May. 0.0343 0.0295 0.0321
09:01-10:00, Thu., 25 May. 0.0344 0.0294 0.0320
08:01-09:00, Thu., 25 May. 0.0343 0.0294 0.0321
07:01-08:00, Thu., 25 May. 0.0349 0.0288 0.0323
06:01-07:00, Thu., 25 May. 0.0345 0.0297 0.0321
05:01-06:00, Thu., 25 May. 0.0357 0.0303 0.0322
04:01-05:00, Thu., 25 May. 0.0357 0.0296 0.0320
03:01-04:00, Thu., 25 May. 0.0348 0.0298 0.0320
02:01-03:00, Thu., 25 May. 0.0346 0.0301 0.0320
01:01-02:00, Thu., 25 May. 0.0346 0.0283 0.0320
00:01-01:00, Thu., 25 May. 0.0335 0.0297 0.0319
23:01-24:00, Wed., 24 May. 0.0343 0.0302 0.0319
22:01-23:00, Wed., 24 May. 0.0343 0.0285 0.0318
21:01-22:00, Wed., 24 May. 0.0346 0.0302 0.0321
20:01-21:00, Wed., 24 May. 0.0348 0.0305 0.0323
19:01-20:00, Wed., 24 May. 0.0343 0.0289 0.0320
18:01-19:00, Wed., 24 May. 0.0346 0.0292 0.0319
17:01-18:00, Wed., 24 May. 0.0350 0.0294 0.0319
16:01-17:00, Wed., 24 May. 0.0347 0.0295 0.0320
15:01-16:00, Wed., 24 May. 0.0340 0.0297 0.0319
14:01-15:00, Wed., 24 May. 0.0347 0.0301 0.0322
13:01-14:00, Wed., 24 May. 0.0346 0.0297 0.0322
12:01-13:00, Wed., 24 May. 0.0347 0.0304 0.0322
11:01-12:00, Wed., 24 May. 0.0339 0.0301 0.0319
10:01-11:00, Wed., 24 May. 0.0346 0.0298 0.0318
09:01-10:00, Wed., 24 May. 0.0343 0.0287 0.0322
08:01-09:00, Wed., 24 May. 0.0343 0.0300 0.0320
07:01-08:00, Wed., 24 May. 0.0346 0.0301 0.0322
06:01-07:00, Wed., 24 May. 0.0347 0.0304 0.0324
05:01-06:00, Wed., 24 May. 0.0342 0.0301 0.0322
04:01-05:00, Wed., 24 May. 0.0353 0.0302 0.0325
03:01-04:00, Wed., 24 May. 0.0363 0.0299 0.0327
02:01-03:00, Wed., 24 May. 0.0343 0.0299 0.0323
01:01-02:00, Wed., 24 May. 0.0349 0.0305 0.0326
00:01-01:00, Wed., 24 May. 0.0357 0.0310 0.0336
23:01-24:00, Tue., 23 May. 0.0395 0.0331 0.0358
22:01-23:00, Tue., 23 May. 0.0437 0.0368 0.0408
21:01-22:00, Tue., 23 May. 0.0424 0.0306 0.0355
20:01-21:00, Tue., 23 May. 0.0344 0.0295 0.0324
19:01-20:00, Tue., 23 May. 0.0353 0.0300 0.0325
18:01-19:00, Tue., 23 May. 0.0384 0.0312 0.0342
17:01-18:00, Tue., 23 May. 0.0426 0.0346 0.0379
16:01-17:00, Tue., 23 May. 0.0478 0.0384 0.0425