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

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.

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 7:30 to 17:30 on Saturday, October 25, 2014

【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






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. 0.0368 0.0315 0.0338
10:01-11:00, Tue., 17 Oct. 0.0360 0.0322 0.0342
09:01-10:00, Tue., 17 Oct. 0.0346 0.0297 0.0323
08:01-09:00, Tue., 17 Oct. 0.0353 0.0308 0.0325
07:01-08:00, Tue., 17 Oct. 0.0357 0.0315 0.0339
06:01-07:00, Tue., 17 Oct. 0.0394 0.0321 0.0352
05:01-06:00, Tue., 17 Oct. 0.0410 0.0345 0.0370
04:01-05:00, Tue., 17 Oct. 0.0376 0.0327 0.0348
03:01-04:00, Tue., 17 Oct. 0.0418 0.0342 0.0376
02:01-03:00, Tue., 17 Oct. 0.0418 0.0348 0.0382
01:01-02:00, Tue., 17 Oct. 0.0399 0.0322 0.0352
00:01-01:00, Tue., 17 Oct. 0.0403 0.0329 0.0360
23:01-24:00, Mon., 16 Oct. 0.0381 0.0329 0.0348
22:01-23:00, Mon., 16 Oct. 0.0412 0.0341 0.0369
21:01-22:00, Mon., 16 Oct. 0.0425 0.0355 0.0383
20:01-21:00, Mon., 16 Oct. 0.0386 0.0321 0.0351
19:01-20:00, Mon., 16 Oct. 0.0429 0.0337 0.0379
18:01-19:00, Mon., 16 Oct. 0.0498 0.0394 0.0441
17:01-18:00, Mon., 16 Oct. 0.0565 0.0452 0.0508
16:01-17:00, Mon., 16 Oct. 0.0549 0.0477 0.0518
15:01-16:00, Mon., 16 Oct. 0.0532 0.0422 0.0481
14:01-15:00, Mon., 16 Oct. 0.0517 0.0404 0.0462
13:01-14:00, Mon., 16 Oct. 0.0493 0.0432 0.0464
12:01-13:00, Mon., 16 Oct. 0.0531 0.0381 0.0459
11:01-12:00, Mon., 16 Oct. 0.0494 0.0397 0.0446
10:01-11:00, Mon., 16 Oct. 0.0533 0.0431 0.0479
09:01-10:00, Mon., 16 Oct. 0.0568 0.0491 0.0526
08:01-09:00, Mon., 16 Oct. 0.0581 0.0497 0.0542
07:01-08:00, Mon., 16 Oct. 0.0506 0.0414 0.0460
06:01-07:00, Mon., 16 Oct. 0.0554 0.0455 0.0491
05:01-06:00, Mon., 16 Oct. 0.0512 0.0453 0.0481
04:01-05:00, Mon., 16 Oct. 0.0534 0.0419 0.0467
03:01-04:00, Mon., 16 Oct. 0.0485 0.0417 0.0446
02:01-03:00, Mon., 16 Oct. 0.0484 0.0384 0.0436
01:01-02:00, Mon., 16 Oct. 0.0492 0.0390 0.0439
00:01-01:00, Mon., 16 Oct. 0.0442 0.0334 0.0370
23:01-24:00, Sun., 15 Oct. 0.0390 0.0332 0.0359
22:01-23:00, Sun., 15 Oct. 0.0405 0.0351 0.0377
21:01-22:00, Sun., 15 Oct. 0.0413 0.0352 0.0373
20:01-21:00, Sun., 15 Oct. 0.0391 0.0296 0.0334
19:01-20:00, Sun., 15 Oct. 0.0334 0.0286 0.0307
18:01-19:00, Sun., 15 Oct. 0.0323 0.0285 0.0305
17:01-18:00, Sun., 15 Oct. 0.0323 0.0287 0.0304
16:01-17:00, Sun., 15 Oct. 0.0328 0.0281 0.0303
15:01-16:00, Sun., 15 Oct. 0.0323 0.0287 0.0306
14:01-15:00, Sun., 15 Oct. 0.0330 0.0287 0.0304
13:01-14:00, Sun., 15 Oct. 0.0333 0.0288 0.0311
12:01-13:00, Sun., 15 Oct. 0.0357 0.0304 0.0329
11:01-12:00, Sun., 15 Oct. 0.0357 0.0294 0.0327
10:01-11:00, Sun., 15 Oct. 0.0336 0.0301 0.0319
09:01-10:00, Sun., 15 Oct. 0.0359 0.0313 0.0327
08:01-09:00, Sun., 15 Oct. 0.0378 0.0316 0.0342
07:01-08:00, Sun., 15 Oct. 0.0370 0.0326 0.0349
06:01-07:00, Sun., 15 Oct. 0.0339 0.0281 0.0310
05:01-06:00, Sun., 15 Oct. 0.0306 0.0272 0.0289
04:01-05:00, Sun., 15 Oct. 0.0311 0.0272 0.0288
03:01-04:00, Sun., 15 Oct. 0.0304 0.0269 0.0286
02:01-03:00, Sun., 15 Oct. 0.0316 0.0269 0.0289
01:01-02:00, Sun., 15 Oct. 0.0302 0.0263 0.0285
00:01-01:00, Sun., 15 Oct. 0.0303 0.0266 0.0286
23:01-24:00, Sat., 14 Oct. 0.0302 0.0267 0.0284
22:01-23:00, Sat., 14 Oct. 0.0307 0.0268 0.0285
21:01-22:00, Sat., 14 Oct. 0.0298 0.0259 0.0282
20:01-21:00, Sat., 14 Oct. 0.0302 0.0264 0.0284
19:01-20:00, Sat., 14 Oct. 0.0306 0.0268 0.0287
18:01-19:00, Sat., 14 Oct. 0.0311 0.0271 0.0291
17:01-18:00, Sat., 14 Oct. 0.0323 0.0269 0.0288
16:01-17:00, Sat., 14 Oct. 0.0307 0.0265 0.0282
15:01-16:00, Sat., 14 Oct. 0.0294 0.0263 0.0281
14:01-15:00, Sat., 14 Oct. 0.0312 0.0265 0.0286
13:01-14:00, Sat., 14 Oct. 0.0323 0.0271 0.0294
12:01-13:00, Sat., 14 Oct. 0.0362 0.0298 0.0320
11:01-12:00, Sat., 14 Oct. 0.0326 0.0260 0.0289
10:01-11:00, Sat., 14 Oct. 0.0309 0.0268 0.0288
09:01-10:00, Sat., 14 Oct. 0.0333 0.0287 0.0307
08:01-09:00, Sat., 14 Oct. 0.0375 0.0316 0.0342
07:01-08:00, Sat., 14 Oct. 0.0396 0.0305 0.0347
06:01-07:00, Sat., 14 Oct. 0.0389 0.0303 0.0334
05:01-06:00, Sat., 14 Oct. 0.0473 0.0367 0.0425
04:01-05:00, Sat., 14 Oct. 0.0506 0.0413 0.0456
03:01-04:00, Sat., 14 Oct. 0.0528 0.0447 0.0492
02:01-03:00, Sat., 14 Oct. 0.0521 0.0403 0.0473
01:01-02:00, Sat., 14 Oct. 0.0444 0.0357 0.0400
00:01-01:00, Sat., 14 Oct. 0.0401 0.0296 0.0343
23:01-24:00, Fri., 13 Oct. 0.0340 0.0296 0.0316
22:01-23:00, Fri., 13 Oct. 0.0333 0.0270 0.0295
21:01-22:00, Fri., 13 Oct. 0.0322 0.0272 0.0295
20:01-21:00, Fri., 13 Oct. 0.0308 0.0270 0.0290
19:01-20:00, Fri., 13 Oct. 0.0310 0.0271 0.0294
18:01-19:00, Fri., 13 Oct. 0.0342 0.0284 0.0317
17:01-18:00, Fri., 13 Oct. 0.0398 0.0318 0.0352
16:01-17:00, Fri., 13 Oct. 0.0426 0.0309 0.0375
15:01-16:00, Fri., 13 Oct. 0.0333 0.0290 0.0312
14:01-15:00, Fri., 13 Oct. 0.0330 0.0285 0.0311
13:01-14:00, Fri., 13 Oct. 0.0339 0.0290 0.0314
12:01-13:00, Fri., 13 Oct. 0.0371 0.0307 0.0336
11:01-12:00, Fri., 13 Oct. 0.0409 0.0308 0.0363
10:01-11:00, Fri., 13 Oct. 0.0387 0.0309 0.0343
09:01-10:00, Fri., 13 Oct. 0.0402 0.0340 0.0360
08:01-09:00, Fri., 13 Oct. 0.0428 0.0355 0.0387
07:01-08:00, Fri., 13 Oct. 0.0418 0.0320 0.0368
06:01-07:00, Fri., 13 Oct. 0.0359 0.0324 0.0340
05:01-06:00, Fri., 13 Oct. 0.0344 0.0288 0.0317
04:01-05:00, Fri., 13 Oct. 0.0311 0.0278 0.0294
03:01-04:00, Fri., 13 Oct. 0.0311 0.0272 0.0292
02:01-03:00, Fri., 13 Oct. 0.0314 0.0273 0.0294
01:01-02:00, Fri., 13 Oct. 0.0307 0.0272 0.0291
00:01-01:00, Fri., 13 Oct. 0.0319 0.0278 0.0296
23:01-24:00, Thu., 12 Oct. 0.0333 0.0280 0.0307
22:01-23:00, Thu., 12 Oct. 0.0326 0.0276 0.0301
21:01-22:00, Thu., 12 Oct. 0.0352 0.0301 0.0325
20:01-21:00, Thu., 12 Oct. 0.0360 0.0272 0.0301
19:01-20:00, Thu., 12 Oct. 0.0311 0.0275 0.0292
18:01-19:00, Thu., 12 Oct. 0.0306 0.0271 0.0291
17:01-18:00, Thu., 12 Oct. 0.0311 0.0273 0.0293
16:01-17:00, Thu., 12 Oct. 0.0325 0.0273 0.0293
15:01-16:00, Thu., 12 Oct. 0.0310 0.0281 0.0293
14:01-15:00, Thu., 12 Oct. 0.0314 0.0275 0.0294
13:01-14:00, Thu., 12 Oct. 0.0319 0.0275 0.0292
12:01-13:00, Thu., 12 Oct. 0.0314 0.0271 0.0293
11:01-12:00, Thu., 12 Oct. 0.0311 0.0270 0.0291
10:01-11:00, Thu., 12 Oct. 0.0313 0.0277 0.0293
09:01-10:00, Thu., 12 Oct. 0.0315 0.0278 0.0294
08:01-09:00, Thu., 12 Oct. 0.0313 0.0269 0.0295
07:01-08:00, Thu., 12 Oct. 0.0318 0.0264 0.0294
06:01-07:00, Thu., 12 Oct. 0.0309 0.0277 0.0292
05:01-06:00, Thu., 12 Oct. 0.0313 0.0266 0.0291
04:01-05:00, Thu., 12 Oct. 0.0309 0.0271 0.0291
03:01-04:00, Thu., 12 Oct. 0.0306 0.0270 0.0290
02:01-03:00, Thu., 12 Oct. 0.0306 0.0268 0.0289
01:01-02:00, Thu., 12 Oct. 0.0305 0.0261 0.0289
00:01-01:00, Thu., 12 Oct. 0.0307 0.0271 0.0289
23:01-24:00, Wed., 11 Oct. 0.0305 0.0268 0.0288
22:01-23:00, Wed., 11 Oct. 0.0310 0.0273 0.0288
21:01-22:00, Wed., 11 Oct. 0.0303 0.0265 0.0283
20:01-21:00, Wed., 11 Oct. 0.0310 0.0272 0.0287
19:01-20:00, Wed., 11 Oct. 0.0302 0.0269 0.0287
18:01-19:00, Wed., 11 Oct. 0.0307 0.0270 0.0287
17:01-18:00, Wed., 11 Oct. 0.0307 0.0264 0.0287
16:01-17:00, Wed., 11 Oct. 0.0305 0.0264 0.0284
15:01-16:00, Wed., 11 Oct. 0.0302 0.0258 0.0284
14:01-15:00, Wed., 11 Oct. 0.0310 0.0272 0.0288
13:01-14:00, Wed., 11 Oct. 0.0304 0.0267 0.0285
12:01-13:00, Wed., 11 Oct. 0.0306 0.0275 0.0290
11:01-12:00, Wed., 11 Oct. 0.0314 0.0271 0.0292
10:01-11:00, Wed., 11 Oct. 0.0309 0.0269 0.0292
09:01-10:00, Wed., 11 Oct. 0.0318 0.0276 0.0291
08:01-09:00, Wed., 11 Oct. 0.0313 0.0280 0.0295
07:01-08:00, Wed., 11 Oct. 0.0313 0.0272 0.0294
06:01-07:00, Wed., 11 Oct. 0.0320 0.0263 0.0295
05:01-06:00, Wed., 11 Oct. 0.0322 0.0277 0.0301
04:01-05:00, Wed., 11 Oct. 0.0325 0.0279 0.0301
03:01-04:00, Wed., 11 Oct. 0.0318 0.0285 0.0302
02:01-03:00, Wed., 11 Oct. 0.0322 0.0285 0.0303
01:01-02:00, Wed., 11 Oct. 0.0328 0.0287 0.0308
00:01-01:00, Wed., 11 Oct. 0.0325 0.0274 0.0301
23:01-24:00, Tue., 10 Oct. 0.0311 0.0274 0.0293
22:01-23:00, Tue., 10 Oct. 0.0306 0.0274 0.0288
21:01-22:00, Tue., 10 Oct. 0.0305 0.0264 0.0286
20:01-21:00, Tue., 10 Oct. 0.0305 0.0262 0.0287
19:01-20:00, Tue., 10 Oct. 0.0306 0.0265 0.0288
18:01-19:00, Tue., 10 Oct. 0.0305 0.0266 0.0284
17:01-18:00, Tue., 10 Oct. 0.0308 0.0266 0.0287
16:01-17:00, Tue., 10 Oct. 0.0302 0.0263 0.0287
15:01-16:00, Tue., 10 Oct. 0.0310 0.0270 0.0287
14:01-15:00, Tue., 10 Oct. 0.0305 0.0271 0.0290
13:01-14:00, Tue., 10 Oct. 0.0303 0.0268 0.0288
12:01-13:00, Tue., 10 Oct. 0.0312 0.0271 0.0291
11:01-12:00, Tue., 10 Oct. 0.0307 0.0273 0.0289
10:01-11:00, Tue., 10 Oct. 0.0302 0.0270 0.0286
09:01-10:00, Tue., 10 Oct. 0.0310 0.0269 0.0290
08:01-09:00, Tue., 10 Oct. 0.0331 0.0270 0.0305
07:01-08:00, Tue., 10 Oct. 0.0332 0.0285 0.0307
06:01-07:00, Tue., 10 Oct. 0.0324 0.0287 0.0308
05:01-06:00, Tue., 10 Oct. 0.0321 0.0282 0.0302
04:01-05:00, Tue., 10 Oct. 0.0321 0.0281 0.0300
03:01-04:00, Tue., 10 Oct. 0.0318 0.0281 0.0297
02:01-03:00, Tue., 10 Oct. 0.0325 0.0286 0.0305
01:01-02:00, Tue., 10 Oct. 0.0314 0.0276 0.0296
00:01-01:00, Tue., 10 Oct. 0.0301 0.0265 0.0283
23:01-24:00, Mon., 09 Oct. 0.0299 0.0253 0.0281
22:01-23:00, Mon., 09 Oct. 0.0314 0.0260 0.0281
21:01-22:00, Mon., 09 Oct. 0.0297 0.0258 0.0280
20:01-21:00, Mon., 09 Oct. 0.0298 0.0255 0.0277
19:01-20:00, Mon., 09 Oct. 0.0299 0.0261 0.0278
18:01-19:00, Mon., 09 Oct. 0.0298 0.0264 0.0279
17:01-18:00, Mon., 09 Oct. 0.0295 0.0257 0.0280
16:01-17:00, Mon., 09 Oct. 0.0296 0.0266 0.0280
15:01-16:00, Mon., 09 Oct. 0.0304 0.0267 0.0283
14:01-15:00, Mon., 09 Oct. 0.0309 0.0262 0.0280
13:01-14:00, Mon., 09 Oct. 0.0303 0.0265 0.0279
12:01-13:00, Mon., 09 Oct. 0.0301 0.0261 0.0280
11:01-12:00, Mon., 09 Oct. 0.0296 0.0256 0.0280
10:01-11:00, Mon., 09 Oct. 0.0299 0.0258 0.0279
09:01-10:00, Mon., 09 Oct. 0.0299 0.0256 0.0277
08:01-09:00, Mon., 09 Oct. 0.0295 0.0260 0.0280
07:01-08:00, Mon., 09 Oct. 0.0305 0.0263 0.0279
06:01-07:00, Mon., 09 Oct. 0.0301 0.0264 0.0281
05:01-06:00, Mon., 09 Oct. 0.0296 0.0263 0.0280
04:01-05:00, Mon., 09 Oct. 0.0299 0.0264 0.0280
03:01-04:00, Mon., 09 Oct. 0.0301 0.0259 0.0280
02:01-03:00, Mon., 09 Oct. 0.0302 0.0261 0.0281
01:01-02:00, Mon., 09 Oct. 0.0298 0.0257 0.0279
00:01-01:00, Mon., 09 Oct. 0.0301 0.0259 0.0281
23:01-24:00, Sun., 08 Oct. 0.0295 0.0250 0.0279
22:01-23:00, Sun., 08 Oct. 0.0298 0.0259 0.0278
21:01-22:00, Sun., 08 Oct. 0.0302 0.0260 0.0280
20:01-21:00, Sun., 08 Oct. 0.0290 0.0252 0.0276
19:01-20:00, Sun., 08 Oct. 0.0293 0.0256 0.0277
18:01-19:00, Sun., 08 Oct. 0.0297 0.0259 0.0277
17:01-18:00, Sun., 08 Oct. 0.0291 0.0258 0.0277
16:01-17:00, Sun., 08 Oct. 0.0303 0.0258 0.0279
15:01-16:00, Sun., 08 Oct. 0.0297 0.0259 0.0278
14:01-15:00, Sun., 08 Oct. 0.0299 0.0261 0.0280
13:01-14:00, Sun., 08 Oct. 0.0302 0.0265 0.0283
12:01-13:00, Sun., 08 Oct. 0.0308 0.0246 0.0284
11:01-12:00, Sun., 08 Oct. 0.0301 0.0265 0.0284
10:01-11:00, Sun., 08 Oct. 0.0311 0.0264 0.0285
09:01-10:00, Sun., 08 Oct. 0.0302 0.0268 0.0285
08:01-09:00, Sun., 08 Oct. 0.0314 0.0269 0.0289
07:01-08:00, Sun., 08 Oct. 0.0316 0.0279 0.0297
06:01-07:00, Sun., 08 Oct. 0.0311 0.0279 0.0295
05:01-06:00, Sun., 08 Oct. 0.0316 0.0275 0.0294
04:01-05:00, Sun., 08 Oct. 0.0310 0.0276 0.0293
03:01-04:00, Sun., 08 Oct. 0.0312 0.0275 0.0293
02:01-03:00, Sun., 08 Oct. 0.0308 0.0276 0.0290
01:01-02:00, Sun., 08 Oct. 0.0307 0.0271 0.0288
00:01-01:00, Sun., 08 Oct. 0.0315 0.0271 0.0292
23:01-24:00, Sat., 07 Oct. 0.0317 0.0263 0.0288
22:01-23:00, Sat., 07 Oct. 0.0300 0.0266 0.0283
21:01-22:00, Sat., 07 Oct. 0.0295 0.0263 0.0282
20:01-21:00, Sat., 07 Oct. 0.0306 0.0264 0.0278
19:01-20:00, Sat., 07 Oct. 0.0295 0.0255 0.0275
18:01-19:00, Sat., 07 Oct. 0.0293 0.0253 0.0273
17:01-18:00, Sat., 07 Oct. 0.0289 0.0259 0.0272
16:01-17:00, Sat., 07 Oct. 0.0290 0.0253 0.0272
15:01-16:00, Sat., 07 Oct. 0.0295 0.0254 0.0271
14:01-15:00, Sat., 07 Oct. 0.0300 0.0250 0.0274
13:01-14:00, Sat., 07 Oct. 0.0296 0.0253 0.0277
12:01-13:00, Sat., 07 Oct. 0.0297 0.0256 0.0277