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, Mon., 11 Dec. 0.0322 0.0286 0.0306
10:01-11:00, Mon., 11 Dec. 0.0332 0.0292 0.0310
09:01-10:00, Mon., 11 Dec. 0.0332 0.0303 0.0317
08:01-09:00, Mon., 11 Dec. 0.0338 0.0302 0.0322
07:01-08:00, Mon., 11 Dec. 0.0335 0.0294 0.0319
06:01-07:00, Mon., 11 Dec. 0.0339 0.0303 0.0317
05:01-06:00, Mon., 11 Dec. 0.0334 0.0293 0.0317
04:01-05:00, Mon., 11 Dec. 0.0344 0.0300 0.0318
03:01-04:00, Mon., 11 Dec. 0.0338 0.0293 0.0310
02:01-03:00, Mon., 11 Dec. 0.0341 0.0290 0.0317
01:01-02:00, Mon., 11 Dec. 0.0336 0.0301 0.0319
00:01-01:00, Mon., 11 Dec. 0.0336 0.0294 0.0314
23:01-24:00, Sun., 10 Dec. 0.0333 0.0290 0.0313
22:01-23:00, Sun., 10 Dec. 0.0330 0.0292 0.0310
21:01-22:00, Sun., 10 Dec. 0.0327 0.0281 0.0305
20:01-21:00, Sun., 10 Dec. 0.0321 0.0284 0.0302
19:01-20:00, Sun., 10 Dec. 0.0332 0.0280 0.0300
18:01-19:00, Sun., 10 Dec. 0.0319 0.0283 0.0298
17:01-18:00, Sun., 10 Dec. 0.0315 0.0279 0.0295
16:01-17:00, Sun., 10 Dec. 0.0308 0.0266 0.0289
15:01-16:00, Sun., 10 Dec. 0.0306 0.0269 0.0288
14:01-15:00, Sun., 10 Dec. 0.0325 0.0278 0.0296
13:01-14:00, Sun., 10 Dec. 0.0315 0.0272 0.0299
12:01-13:00, Sun., 10 Dec. 0.0323 0.0284 0.0305
11:01-12:00, Sun., 10 Dec. 0.0321 0.0291 0.0307
10:01-11:00, Sun., 10 Dec. 0.0346 0.0294 0.0314
09:01-10:00, Sun., 10 Dec. 0.0339 0.0304 0.0319
08:01-09:00, Sun., 10 Dec. 0.0347 0.0298 0.0325
07:01-08:00, Sun., 10 Dec. 0.0345 0.0306 0.0327
06:01-07:00, Sun., 10 Dec. 0.0341 0.0304 0.0321
05:01-06:00, Sun., 10 Dec. 0.0337 0.0304 0.0320
04:01-05:00, Sun., 10 Dec. 0.0333 0.0299 0.0317
03:01-04:00, Sun., 10 Dec. 0.0336 0.0299 0.0315
02:01-03:00, Sun., 10 Dec. 0.0325 0.0293 0.0308
01:01-02:00, Sun., 10 Dec. 0.0326 0.0285 0.0306
00:01-01:00, Sun., 10 Dec. 0.0323 0.0281 0.0304
23:01-24:00, Sat., 09 Dec. 0.0340 0.0285 0.0306
22:01-23:00, Sat., 09 Dec. 0.0327 0.0293 0.0309
21:01-22:00, Sat., 09 Dec. 0.0325 0.0287 0.0305
20:01-21:00, Sat., 09 Dec. 0.0325 0.0282 0.0300
19:01-20:00, Sat., 09 Dec. 0.0314 0.0273 0.0296
18:01-19:00, Sat., 09 Dec. 0.0311 0.0276 0.0292
17:01-18:00, Sat., 09 Dec. 0.0307 0.0272 0.0288
16:01-17:00, Sat., 09 Dec. 0.0313 0.0276 0.0289
15:01-16:00, Sat., 09 Dec. 0.0320 0.0272 0.0290
14:01-15:00, Sat., 09 Dec. 0.0323 0.0275 0.0292
13:01-14:00, Sat., 09 Dec. 0.0314 0.0267 0.0295
12:01-13:00, Sat., 09 Dec. 0.0316 0.0279 0.0295
11:01-12:00, Sat., 09 Dec. 0.0319 0.0277 0.0296
10:01-11:00, Sat., 09 Dec. 0.0313 0.0278 0.0294
09:01-10:00, Sat., 09 Dec. 0.0316 0.0277 0.0296
08:01-09:00, Sat., 09 Dec. 0.0324 0.0285 0.0303
07:01-08:00, Sat., 09 Dec. 0.0319 0.0284 0.0300
06:01-07:00, Sat., 09 Dec. 0.0312 0.0277 0.0297
05:01-06:00, Sat., 09 Dec. 0.0303 0.0275 0.0293
04:01-05:00, Sat., 09 Dec. 0.0315 0.0263 0.0292
03:01-04:00, Sat., 09 Dec. 0.0326 0.0278 0.0296
02:01-03:00, Sat., 09 Dec. 0.0316 0.0280 0.0296
01:01-02:00, Sat., 09 Dec. 0.0315 0.0274 0.0296
00:01-01:00, Sat., 09 Dec. 0.0316 0.0279 0.0298
23:01-24:00, Fri., 08 Dec. 0.0339 0.0296 0.0319
22:01-23:00, Fri., 08 Dec. 0.0415 0.0316 0.0363
21:01-22:00, Fri., 08 Dec. 0.0492 0.0360 0.0410
20:01-21:00, Fri., 08 Dec. 0.0591 0.0460 0.0530
19:01-20:00, Fri., 08 Dec. 0.0554 0.0373 0.0462
18:01-19:00, Fri., 08 Dec. 0.0392 0.0318 0.0349
17:01-18:00, Fri., 08 Dec. 0.0363 0.0310 0.0332
16:01-17:00, Fri., 08 Dec. 0.0367 0.0313 0.0335
15:01-16:00, Fri., 08 Dec. 0.0345 0.0299 0.0319
14:01-15:00, Fri., 08 Dec. 0.0325 0.0284 0.0310
13:01-14:00, Fri., 08 Dec. 0.0331 0.0293 0.0310
12:01-13:00, Fri., 08 Dec. 0.0333 0.0297 0.0318
11:01-12:00, Fri., 08 Dec. 0.0353 0.0306 0.0323
10:01-11:00, Fri., 08 Dec. 0.0359 0.0312 0.0331
09:01-10:00, Fri., 08 Dec. 0.0348 0.0309 0.0330
08:01-09:00, Fri., 08 Dec. 0.0360 0.0311 0.0329
07:01-08:00, Fri., 08 Dec. 0.0345 0.0299 0.0323
06:01-07:00, Fri., 08 Dec. 0.0342 0.0304 0.0324
05:01-06:00, Fri., 08 Dec. 0.0340 0.0302 0.0319
04:01-05:00, Fri., 08 Dec. 0.0342 0.0297 0.0319
03:01-04:00, Fri., 08 Dec. 0.0339 0.0301 0.0319
02:01-03:00, Fri., 08 Dec. 0.0337 0.0296 0.0318
01:01-02:00, Fri., 08 Dec. 0.0340 0.0298 0.0320
00:01-01:00, Fri., 08 Dec. 0.0336 0.0295 0.0314
23:01-24:00, Thu., 07 Dec. 0.0332 0.0294 0.0312
22:01-23:00, Thu., 07 Dec. 0.0323 0.0285 0.0308
21:01-22:00, Thu., 07 Dec. 0.0335 0.0292 0.0309
20:01-21:00, Thu., 07 Dec. 0.0326 0.0285 0.0302
19:01-20:00, Thu., 07 Dec. 0.0318 0.0280 0.0299
18:01-19:00, Thu., 07 Dec. 0.0313 0.0277 0.0295
17:01-18:00, Thu., 07 Dec. 0.0316 0.0274 0.0296
16:01-17:00, Thu., 07 Dec. 0.0314 0.0278 0.0294
15:01-16:00, Thu., 07 Dec. 0.0313 0.0274 0.0296
14:01-15:00, Thu., 07 Dec. 0.0317 0.0276 0.0295
13:01-14:00, Thu., 07 Dec. 0.0319 0.0272 0.0296
12:01-13:00, Thu., 07 Dec. 0.0326 0.0280 0.0302
11:01-12:00, Thu., 07 Dec. 0.0324 0.0291 0.0304
10:01-11:00, Thu., 07 Dec. 0.0323 0.0284 0.0306
09:01-10:00, Thu., 07 Dec. 0.0337 0.0300 0.0318
08:01-09:00, Thu., 07 Dec. 0.0350 0.0299 0.0326
07:01-08:00, Thu., 07 Dec. 0.0334 0.0305 0.0320
06:01-07:00, Thu., 07 Dec. 0.0343 0.0300 0.0320
05:01-06:00, Thu., 07 Dec. 0.0357 0.0300 0.0324
04:01-05:00, Thu., 07 Dec. 0.0345 0.0298 0.0321
03:01-04:00, Thu., 07 Dec. 0.0332 0.0293 0.0311
02:01-03:00, Thu., 07 Dec. 0.0317 0.0283 0.0300
01:01-02:00, Thu., 07 Dec. 0.0330 0.0284 0.0299
00:01-01:00, Thu., 07 Dec. 0.0328 0.0284 0.0300
23:01-24:00, Wed., 06 Dec. 0.0323 0.0290 0.0303
22:01-23:00, Wed., 06 Dec. 0.0338 0.0285 0.0304
21:01-22:00, Wed., 06 Dec. 0.0326 0.0283 0.0305
20:01-21:00, Wed., 06 Dec. 0.0323 0.0285 0.0305
19:01-20:00, Wed., 06 Dec. 0.0319 0.0272 0.0300
18:01-19:00, Wed., 06 Dec. 0.0315 0.0280 0.0296
17:01-18:00, Wed., 06 Dec. 0.0328 0.0277 0.0296
16:01-17:00, Wed., 06 Dec. 0.0318 0.0278 0.0296
15:01-16:00, Wed., 06 Dec. 0.0315 0.0280 0.0297
14:01-15:00, Wed., 06 Dec. 0.0320 0.0272 0.0299
13:01-14:00, Wed., 06 Dec. 0.0320 0.0284 0.0302
12:01-13:00, Wed., 06 Dec. 0.0319 0.0276 0.0302
11:01-12:00, Wed., 06 Dec. 0.0325 0.0277 0.0298
10:01-11:00, Wed., 06 Dec. 0.0322 0.0280 0.0302
09:01-10:00, Wed., 06 Dec. 0.0325 0.0283 0.0301
08:01-09:00, Wed., 06 Dec. 0.0316 0.0282 0.0301
07:01-08:00, Wed., 06 Dec. 0.0322 0.0280 0.0304
06:01-07:00, Wed., 06 Dec. 0.0314 0.0279 0.0297
05:01-06:00, Wed., 06 Dec. 0.0316 0.0281 0.0300
04:01-05:00, Wed., 06 Dec. 0.0317 0.0274 0.0297
03:01-04:00, Wed., 06 Dec. 0.0318 0.0279 0.0296
02:01-03:00, Wed., 06 Dec. 0.0311 0.0275 0.0293
01:01-02:00, Wed., 06 Dec. 0.0313 0.0266 0.0294
00:01-01:00, Wed., 06 Dec. 0.0308 0.0276 0.0291
23:01-24:00, Tue., 05 Dec. 0.0312 0.0272 0.0294
22:01-23:00, Tue., 05 Dec. 0.0310 0.0270 0.0291
21:01-22:00, Tue., 05 Dec. 0.0313 0.0270 0.0290
20:01-21:00, Tue., 05 Dec. 0.0307 0.0272 0.0290
19:01-20:00, Tue., 05 Dec. 0.0310 0.0272 0.0289
18:01-19:00, Tue., 05 Dec. 0.0310 0.0273 0.0289
17:01-18:00, Tue., 05 Dec. 0.0308 0.0277 0.0291
16:01-17:00, Tue., 05 Dec. 0.0312 0.0263 0.0291
15:01-16:00, Tue., 05 Dec. 0.0312 0.0274 0.0291
14:01-15:00, Tue., 05 Dec. 0.0309 0.0269 0.0292
13:01-14:00, Tue., 05 Dec. 0.0311 0.0273 0.0295
12:01-13:00, Tue., 05 Dec. 0.0317 0.0273 0.0296
11:01-12:00, Tue., 05 Dec. 0.0318 0.0282 0.0299
10:01-11:00, Tue., 05 Dec. 0.0329 0.0280 0.0304
09:01-10:00, Tue., 05 Dec. 0.0330 0.0287 0.0309
08:01-09:00, Tue., 05 Dec. 0.0333 0.0292 0.0313
07:01-08:00, Tue., 05 Dec. 0.0327 0.0289 0.0312
06:01-07:00, Tue., 05 Dec. 0.0334 0.0291 0.0311
05:01-06:00, Tue., 05 Dec. 0.0341 0.0288 0.0310
04:01-05:00, Tue., 05 Dec. 0.0329 0.0289 0.0311
03:01-04:00, Tue., 05 Dec. 0.0328 0.0283 0.0306
02:01-03:00, Tue., 05 Dec. 0.0324 0.0292 0.0307
01:01-02:00, Tue., 05 Dec. 0.0331 0.0283 0.0307
00:01-01:00, Tue., 05 Dec. 0.0323 0.0283 0.0299
23:01-24:00, Mon., 04 Dec. 0.0324 0.0270 0.0298
22:01-23:00, Mon., 04 Dec. 0.0320 0.0283 0.0301
21:01-22:00, Mon., 04 Dec. 0.0353 0.0292 0.0318
20:01-21:00, Mon., 04 Dec. 0.0354 0.0304 0.0337
19:01-20:00, Mon., 04 Dec. 0.0367 0.0317 0.0345
18:01-19:00, Mon., 04 Dec. 0.0386 0.0302 0.0336
17:01-18:00, Mon., 04 Dec. 0.0353 0.0295 0.0321
16:01-17:00, Mon., 04 Dec. 0.0326 0.0279 0.0301
15:01-16:00, Mon., 04 Dec. 0.0326 0.0286 0.0300
14:01-15:00, Mon., 04 Dec. 0.0319 0.0281 0.0298
13:01-14:00, Mon., 04 Dec. 0.0327 0.0276 0.0299
12:01-13:00, Mon., 04 Dec. 0.0321 0.0285 0.0306
11:01-12:00, Mon., 04 Dec. 0.0325 0.0293 0.0308
10:01-11:00, Mon., 04 Dec. 0.0345 0.0294 0.0314
09:01-10:00, Mon., 04 Dec. 0.0337 0.0296 0.0318
08:01-09:00, Mon., 04 Dec. 0.0344 0.0301 0.0321
07:01-08:00, Mon., 04 Dec. 0.0354 0.0303 0.0325
06:01-07:00, Mon., 04 Dec. 0.0356 0.0301 0.0327
05:01-06:00, Mon., 04 Dec. 0.0351 0.0303 0.0322
04:01-05:00, Mon., 04 Dec. 0.0340 0.0303 0.0319
03:01-04:00, Mon., 04 Dec. 0.0332 0.0298 0.0316
02:01-03:00, Mon., 04 Dec. 0.0332 0.0294 0.0312
01:01-02:00, Mon., 04 Dec. 0.0329 0.0293 0.0311
00:01-01:00, Mon., 04 Dec. 0.0332 0.0296 0.0312
23:01-24:00, Sun., 03 Dec. 0.0326 0.0291 0.0310
22:01-23:00, Sun., 03 Dec. 0.0322 0.0286 0.0303
21:01-22:00, Sun., 03 Dec. 0.0326 0.0282 0.0304
20:01-21:00, Sun., 03 Dec. 0.0323 0.0280 0.0302
19:01-20:00, Sun., 03 Dec. 0.0317 0.0279 0.0299
18:01-19:00, Sun., 03 Dec. 0.0317 0.0266 0.0296
17:01-18:00, Sun., 03 Dec. 0.0322 0.0269 0.0294
16:01-17:00, Sun., 03 Dec. 0.0314 0.0276 0.0295
15:01-16:00, Sun., 03 Dec. 0.0309 0.0276 0.0294
14:01-15:00, Sun., 03 Dec. 0.0318 0.0268 0.0296
13:01-14:00, Sun., 03 Dec. 0.0315 0.0276 0.0299
12:01-13:00, Sun., 03 Dec. 0.0320 0.0279 0.0297
11:01-12:00, Sun., 03 Dec. 0.0318 0.0287 0.0303
10:01-11:00, Sun., 03 Dec. 0.0327 0.0283 0.0307
09:01-10:00, Sun., 03 Dec. 0.0339 0.0293 0.0311
08:01-09:00, Sun., 03 Dec. 0.0337 0.0297 0.0315
07:01-08:00, Sun., 03 Dec. 0.0335 0.0290 0.0311
06:01-07:00, Sun., 03 Dec. 0.0335 0.0282 0.0312
05:01-06:00, Sun., 03 Dec. 0.0334 0.0287 0.0308
04:01-05:00, Sun., 03 Dec. 0.0325 0.0286 0.0305
03:01-04:00, Sun., 03 Dec. 0.0322 0.0283 0.0302
02:01-03:00, Sun., 03 Dec. 0.0323 0.0274 0.0298
01:01-02:00, Sun., 03 Dec. 0.0324 0.0280 0.0300
00:01-01:00, Sun., 03 Dec. 0.0316 0.0276 0.0297
23:01-24:00, Sat., 02 Dec. 0.0325 0.0277 0.0301
22:01-23:00, Sat., 02 Dec. 0.0318 0.0283 0.0301
21:01-22:00, Sat., 02 Dec. 0.0311 0.0279 0.0294
20:01-21:00, Sat., 02 Dec. 0.0314 0.0272 0.0290
19:01-20:00, Sat., 02 Dec. 0.0309 0.0257 0.0291
18:01-19:00, Sat., 02 Dec. 0.0306 0.0270 0.0289
17:01-18:00, Sat., 02 Dec. 0.0319 0.0270 0.0287
16:01-17:00, Sat., 02 Dec. 0.0305 0.0268 0.0288
15:01-16:00, Sat., 02 Dec. 0.0306 0.0274 0.0287
14:01-15:00, Sat., 02 Dec. 0.0308 0.0270 0.0289
13:01-14:00, Sat., 02 Dec. 0.0309 0.0278 0.0291
12:01-13:00, Sat., 02 Dec. 0.0306 0.0274 0.0290
11:01-12:00, Sat., 02 Dec. 0.0312 0.0268 0.0291
10:01-11:00, Sat., 02 Dec. 0.0315 0.0276 0.0296
09:01-10:00, Sat., 02 Dec. 0.0317 0.0274 0.0294
08:01-09:00, Sat., 02 Dec. 0.0320 0.0273 0.0296
07:01-08:00, Sat., 02 Dec. 0.0314 0.0271 0.0294
06:01-07:00, Sat., 02 Dec. 0.0318 0.0276 0.0297
05:01-06:00, Sat., 02 Dec. 0.0319 0.0283 0.0298
04:01-05:00, Sat., 02 Dec. 0.0333 0.0279 0.0302
03:01-04:00, Sat., 02 Dec. 0.0318 0.0279 0.0301
02:01-03:00, Sat., 02 Dec. 0.0314 0.0283 0.0300
01:01-02:00, Sat., 02 Dec. 0.0320 0.0271 0.0296
00:01-01:00, Sat., 02 Dec. 0.0321 0.0275 0.0296
23:01-24:00, Fri., 01 Dec. 0.0328 0.0276 0.0297
22:01-23:00, Fri., 01 Dec. 0.0324 0.0278 0.0296
21:01-22:00, Fri., 01 Dec. 0.0312 0.0279 0.0295
20:01-21:00, Fri., 01 Dec. 0.0314 0.0275 0.0295
19:01-20:00, Fri., 01 Dec. 0.0317 0.0272 0.0293
18:01-19:00, Fri., 01 Dec. 0.0317 0.0273 0.0293
17:01-18:00, Fri., 01 Dec. 0.0309 0.0274 0.0293
16:01-17:00, Fri., 01 Dec. 0.0305 0.0271 0.0291
15:01-16:00, Fri., 01 Dec. 0.0311 0.0278 0.0292
14:01-15:00, Fri., 01 Dec. 0.0318 0.0277 0.0293
13:01-14:00, Fri., 01 Dec. 0.0305 0.0272 0.0292
12:01-13:00, Fri., 01 Dec. 0.0310 0.0277 0.0293