Health Canada's Radiation Monitoring Data and the Nuclear Emergency in Japan

Update: For recent informationon radiation monitoring in Canada, data from Health Canada's networks can be found on the Radiation Dose Data from the Fixed Point Surveillance Network page. Detailed information on radiation from Japan, including radiation levels in food products, seafood, and ocean water, can be found on the Additional information on radiation from Japan webpage. Information from all of these sources indicates that radiation levels resulting from the Fukushima accident are far below levels of concern to public health in Canada.

Health Canada continues to monitor and review radiation levels in Canada and worldwide, using its monitoring networks and its collaborative relationships with the international community.  This includes information related to the Fukushima Daiichi nuclear accident.  Should data from these monitoring programs indicate a need for additional efforts, Health Canada will promptly notify the Public Health authorities (including provincial authorities) of the situation and provide guidance on how to best address the issue/concern.  For questions regarding food safety, please  contact the Canadian Food Inspection Agency.

For questions regarding the on-site status of the Fukushima Daiichi Nuclear Power Station in Japan, please contact the Canadian Nuclear Safety Commission at info@cnsc-ccsn.gc.ca. Japan's Nuclear Regulation Authority Reports on Conditions at TEPCO's Fukushima Daiichi Nuclear Power Station are  also available.

As part of routine operations, Health Canada's Radiation Protection Bureau monitors radiation levels across Canada 24/7 through networks of stations which measure radioactivity in air and other environmental samples (see Health Canada's pages on Environmental Radiation for a detailed description of these networks).

In response to the Fukushima Daiichi nuclear accident in Japan, data from two of these networks comprising more than 100 radiation monitoring stations was made available at an increased frequency in 2011. Measurements from these networks have confirmed, and continue to confirm, that the quantities of radioactive materials that reached Canada as a result of the Fukushima Daiichi nuclear accident were very small and did not pose any health risk to Canadians. The very slight increases in radiation across the country, observed during the first few weeks following the onset of the incident, were smaller than the normal day to day fluctuations from background radiation. An overview of these networks and their data are provided below.

The first network (Fixed Point Network - FPS) measures radiation levels in air in real time. The summaries from this network provide an indication of the amount of radiation in the vicinity of the monitoring stations, including both natural background radiation as well as radionuclides from the damaged reactors that may have been carried by the wind. The increased monitoring data for March to August 2011 is available online. Routine data from this network, reported on a monthly basis, is also available.

The second network (which includes Canadian stations that are part of the global Comprehensive Nuclear Test Ban Treaty monitoring network - CTBT) can detect much lower quantities of radioactivity in air, but not in real time. The monitoring stations in this network collect air over 24-hour sampling periods so that any radioisotopes present in the samples can be measured at much lower levels by gamma radiation detectors. This network detected the first radioactive isotopes in Canada coming from the damaged Japanese reactors, in Sidney, BC. While data from this network is not routinely reported, in response to the Fukushima Daiichi nuclear accident, the data for March to August 2011 is also available online.

A Note on Data Reporting

All monitoring stations in these networks are extremely sensitive and capable of detecting minute quantities of radioactivity as well as identifying a broad range of individual radionuclides. However, Health Canada only reports online the results for the principal radionuclides of interest in assessing radiation dose, as well as data for ¹³³Xe.

In response to the Fukushima Daiichi nuclear accident, daily data for March and April 2011 are available online. Given that no elevated levels of radiation associated with the damaged reactors were observed after the first few weeks of the emergency, that no additional significant radioactive releases from the damaged Japanese reactors occurred, and that the levels of radiation across Canada continued to be within normal background levels, Health Canada changed the frequency of data publishing from all monitoring networks on the Website to a single day, once a week starting the first week in May 2011. While data continued to be collected at the same frequency, this weekly report includes a single daily dose calculated mid week from FPS monitoring stations across Canada (as listed in the currently posted charts), as well as the data on the concentration of radioisotopes in the air from the CTBT stations (as listed in the currently posted charts).

On September 15, 2011, Health Canada ended its weekly data postings, resuming its previous schedule of quarterly postings of the fixed point data. This change does not impact Health Canada's continuous and ongoing monitoring. These changes in posts to the website were made as radiation levels across Canada are within normal background levels and there is no cause for concern. Please note that Health Canada continues to closely monitor the situation in Japan and review data received from the monitoring systems in Canada on a daily basis. If the situation changes, Health Canada will reassess the frequency of reporting on the website.

• What Do Radiation Measurements Mean?

On this page:

• Fixed Point Network
  • March 2011 - Daily Dose Radiation Levels (µSv/day)
  • April 2011 - Daily Dose Radiation Levels (µSv/day)
  • May 2011 - Weekly Dose Radiation Levels (µSv/day)
  • June 2011 - Weekly Dose Radiation Levels (µSv/day)
  • July 2011 - Weekly Dose Radiation Levels (µSv/day)
  • August 2011 - Weekly Dose Radiation Levels (µSv/day)
  • September 2011 - Weekly Dose Radiation Levels (µSv/day)
  • Ongoing - Quarterly Dose Radiation Levels (nGv/month)
• Comprehensive Nuclear Test Ban Treaty Network Stations
  • March 2011 - Radiation Concentration (mBq/m³ and Bq/m³)
  • April 2011 - Radiation Concentration (mBq/m³ and Bq/m³)
  • May 2011 - Radiation Concentration (mBq/m³ and Bq/m³)
  • June 2011 - Radiation Concentration (mBq/m³ and Bq/m³)
  • July 2011 - Radiation Concentration (mBq/m³ and Bq/m³)
  • August 2011 - Radiation Concentration (mBq/m³ and Bq/m³)
  • September 2011 - Radiation Concentration (mBq/m³ and Bq/m³)

Fixed Point Network

Although only a slight increase in the level of radioactivity was measured in the first few weeks following the Fukushima Daiichi nuclear accident, it is possible to identify the radioisotopes in the radiation. This allowed Health Canada to verify that the nuclear accident was the source of the isotopes. For example, xenon was detected on the west coast. Xenon is an isotope produced from a nuclear reactor. No unusual measurements have been detected since that time.

March 2011 - Daily Dose Radiation Levels (µSv/day)

Summary: Data received is as expected and does not pose a health risk to Canadians. Even though the data table does not show an increase over and above the normal day to day fluctuations, further identification of the radioactive material revealed very minute levels of isotopes which are indicative of the release in Japan. The actual dose increase in radiation measured was 0.0005µSv, which is so small that you cannot discern it from the background.

• What Do Radiation Measurements Mean?

March 2011 - Health Canada Fixed Point Network Daily Dose Summary (µSv/day)

Station	P/T	Baseline (2010)			10	11	12	13	14	15	16	17	18	19	20
		Min	Average	Max
x dose data for this date was not collected due to problems with equipment or data transfer
Calgary	AB	0.28	0.48	0.64	0.45	0.48	0.46	0.44	0.43	0.42	0.44	0.48	0.43	0.45	0.48
Sidney	BC	0.12	0.38	0.57	0.36	0.36	0.37	0.37	0.31	0.37	0.36	0.36	0.39	0.42	0.37
Victoria	BC	0.21	0.23	0.35	0.23	0.22	0.22	0.23	0.25	0.23	0.23	0.22	0.23	0.26	0.24
Vancouver	BC	0.07	0.44	0.59	0.42	0.42	0.42	0.43	0.43	0.44	0.42	0.41	0.43	0.50	0.44
Nanaimo	BC	0.08	0.35	0.49	0.35	0.34	0.36	0.41	0.37	0.38	0.34	0.34	0.37	0.39	0.35
Winnipeg	MB	0.31	0.38	1.06	0.32	0.32	0.32	0.29	0.31	0.32	0.34	0.34	0.30	0.31	0.39
Saint John	NB	0.56	0.68	0.78	0.66	0.66	0.69	0.68	0.68	0.67	0.67	0.68	0.70	0.68	0.68
St. John's	NL	0.49	0.68	0.76	0.61	0.61	0.62	0.64	0.67	0.54	0.54	0.57	0.63	0.65	0.62
Digby	NS	0.17	1.10	1.20	1.07	1.08	1.10	1.09	1.08	x	1.08	1.09	1.10	1.09	1.08
Halifax	NS	0.10	0.80	0.92	0.80	0.81	0.82	0.82	0.79	0.78	0.81	0.81	0.83	0.82	0.81
Yellowknife	NWT	0.20	0.85	1.02	0.57	0.55	0.58	0.58	0.60	0.59	0.56	0.56	0.57	0.57	0.56
Amherstburg	ON	0.42	0.54	0.84	0.52	0.52	0.50	0.51	0.49	0.52	0.56	0.53	0.54	0.52	0.53
Thunder Bay	ON	0.39	0.46	1.04	0.40	0.43	0.41	0.40	0.41	0.42	0.42	0.49	0.42	0.41	0.47
Kincardine	ON	0.26	0.36	0.68	0.44	0.44	0.34	0.33	0.28	0.29	0.37	0.34	0.38	0.34	0.34
Toronto	ON	0.08	0.28	0.53	0.31	0.34	0.25	0.29	0.24	0.24	0.30	0.27	0.27	0.25	0.25
Port Hope	ON	0.02	0.57	0.98	0.63	0.62	0.55	0.58	0.54	0.54	0.59	0.56	0.57	0.55	0.54
Pickering	ON	0.47	0.53	0.82	0.55	0.58	0.48	0.52	0.48	0.48	0.56	0.50	0.51	0.49	0.49
Oshawa	ON	0.44	0.49	0.87	0.57	0.53	0.46	0.49	0.45	0.46	0.53	0.47	0.48	0.46	0.46
Markham	ON	0.14	0.54	0.84	0.58	0.60	0.50	0.54	0.50	0.50	0.57	0.52	0.53	0.51	0.51
Ottawa	ON	0.16	0.40	0.57	0.35	0.33	0.31	0.32	0.33	0.34	0.36	0.36	0.40	0.37	0.38
Petawawa	ON	0.39	0.64	0.89	0.42	0.41	0.36	0.39	0.38	0.37	0.38	0.39	0.47	0.51	0.47
Charlottetown	PEI	0.46	0.54	0.68	0.46	0.46	0.49	0.51	0.49	0.49	0.50	0.51	0.57	0.51	0.51
Montréal	QC	0.34	0.44	0.58	0.43	0.40	0.42	0.42	0.41	0.41	0.43	0.43	0.47	0.42	0.42
Trois-Rivières	QC	0.04	0.35	0.98	0.22	0.18	0.18	0.16	0.16	0.16	0.18	0.17	0.24	0.20	0.20
Leprad	QC	0.48	0.62	0.82	0.45	0.39	0.43	0.45	0.46	0.46	0.49	0.48	0.55	0.51	0.51
Regina	SK	0.44	0.76	1.06	0.45	0.45	0.34	0.38	0.40	0.35	0.41	0.36	0.36	0.38	0.37

March 2011 - Health Canada Fixed Point Network Daily Dose Summary (µSv/day)

Station	P/T	Baseline (2010)			21	22	23	24	25	26	27	28	29	30	31
		Min	Average	Max
x dose data for this date was not collected due to problems with equipment or data transfer
Calgary	AB	0.28	0.48	0.64	0.48	0.45	0.46	0.44	0.45	0.48	0.46	0.44	0.45	0.44	0.44
Sidney	BC	0.12	0.38	0.57	0.44	0.37	0.37	0.37	0.42	0.37	0.37	0.37	0.37	0.36	0.36
Victoria	BC	0.21	0.23	0.35	0.29	0.23	0.23	0.24	0.26	0.23	0.23	0.23	0.23	0.23	0.23
Vancouver	BC	0.07	0.44	0.59	0.51	0.43	0.42	0.43	0.45	0.44	0.45	0.43	0.44	0.47	0.43
Nanaimo	BC	0.08	0.35	0.49	0.38	0.35	0.34	0.35	0.37	0.35	0.35	0.35	0.35	0.34	0.34
Winnipeg	MB	0.31	0.38	1.06	0.34	0.32	0.32	0.32	0.33	0.32	0.32	0.33	0.33	0.33	0.35
Saint John	NB	0.56	0.68	0.78	0.68	0.67	0.68	0.68	0.68	0.68	0.67	0.68	0.68	0.68	0.68
St. John's	NL	0.49	0.68	0.76	0.61	0.62	0.63	0.57	0.56	0.51	x	x	0.51	0.51	0.51
Digby	NS	0.17	1.10	1.20	1.10	1.08	1.09	1.09	1.09	1.09	0.97	1.08	1.09	1.09	1.09
Halifax	NS	0.10	0.80	0.92	0.79	0.78	0.81	0.80	0.80	0.83	0.82	0.80	0.81	0.80	0.81
Yellowknife	NWT	0.20	0.85	1.02	0.55	0.56	0.56	0.56	0.55	0.55	0.56	0.56	0.56	0.57	0.58
Amherstburg	ON	0.42	0.54	0.84	0.61	0.55	0.59	0.50	0.51	0.51	0.51	0.52	0.52	0.53	0.52
Thunder Bay	ON	0.39	0.46	1.04	0.44	0.42	0.41	0.41	0.42	0.42	0.43	0.43	0.43	0.43	0.43
Kincardine	ON	0.26	0.36	0.68	0.39	0.35	0.38	0.31	0.31	0.32	0.32	0.32	0.33	0.34	0.35
Toronto	ON	0.08	0.28	0.53	0.30	0.25	0.28	0.23	0.23	0.24	0.24	0.24	0.24	0.25	0.25
Port Hope	ON	0.02	0.57	0.98	0.61	0.55	0.55	0.55	0.54	0.54	0.54	0.54	0.54	0.55	0.57
Pickering	ON	0.47	0.53	0.82	0.57	0.49	0.51	0.49	0.49	0.49	0.49	0.49	0.49	0.50	0.50
Oshawa	ON	0.44	0.49	0.87	0.54	0.47	0.48	0.47	0.46	0.46	0.46	0.46	0.46	0.47	0.47
Markham	ON	0.14	0.54	0.84	0.59	0.51	0.54	0.50	0.50	0.50	0.50	0.50	0.50	x	x
Ottawa	ON	0.16	0.40	0.57	0.41	0.37	0.37	0.38	0.37	0.38	0.37	0.37	0.32	0.38	0.38
Petawawa	ON	0.39	0.64	0.89	0.49	0.46	0.46	0.47	0.47	0.47	0.47	0.47	0.48	0.51	0.52
Charlottetown	PEI	0.46	0.54	0.68	0.51	0.51	0.51	0.51	0.51	0.52	0.52	0.52	0.52	0.52	0.52
Montréal	QC	0.34	0.44	0.58	0.45	0.43	0.42	0.43	0.42	0.42	0.41	0.42	0.42	0.43	0.43
Trois-Rivières	QC	0.04	0.35	0.98	0.23	0.22	0.21	0.21	0.22	0.21	0.21	0.21	0.22	0.22	0.23
Leprad	QC	0.48	0.62	0.82	0.53	0.53	0.52	0.53	0.53	0.53	0.53	0.53	0.54	0.54	0.55
Regina	SK	0.44	0.76	1.06	0.35	0.34	0.33	0.34	0.34	0.34	0.33	0.33	0.33	0.38	0.37

March 2011 - Additional British Columbia and Yukon Fixed Point Daily Dose Summary (µSv/day)

Station	P/T	Baseline			23	24	25	26	27	28	29	30	31
		Min	Average	Max
x dose data for this date was not collected due to problems with equipment or data transfer Supplementary detectors deployed in March: The Min, Max and Median numbers are only based on the first 35 days of continuous operation of these systems so it is reasonable to expect that future values will be slightly below/above the current Min/Max values.
Prince Rupert	BC	0.41	0.42	0.45	x	0.43	0.43	0.44	0.43	0.43	0.43	0.43	0.42
Prince George	BC	0.56	0.59	0.62	0.57	0.58	0.58	0.58	0.59	0.58	0.56	0.57	0.57
Kamloops	BC	0.46	0.48	0.53	x	0.53	0.51	0.51	0.51	0.52	0.47	0.47	0.48
Burnaby	BC	0.47	0.49	0.54	x	0.48	0.50	0.48	0.50	0.48	0.50	0.54	0.48
Port Hardy	BC	0.25	0.26	0.29	x	0.26	0.27	0.29	0.27	0.26	0.27	0.28	0.26
Tofino	BC	0.32	0.33	0.37	0.33	0.34	0.37	0.35	0.35	0.34	0.35	0.36	0.33
Abbotsford	BC	0.28	0.29	0.31	0.29	0.29	0.30	0.29	0.29	0.28	0.29	0.31	0.28
Kelowna	BC	0.84	0.87	0.93	0.87	0.88	0.92	0.89	0.93	0.89	0.87	0.87	0.84
Whitehorse	YT	0.25	0.27	0.29	x	0.26	0.27	0.29	0.27	0.26	0.27	0.28	0.26

April 2011 - Daily Dose Radiation Levels (µSv/day)

Analysis of the measured data shows that levels of total radiation are within normal background variations. Therefore starting April 1 2011, the daily dose data will be available for select stations across Canada and will only be updated three times a week; however, Health Canada will continue to monitor the data from all stations on a daily basis.

Summary: Data received is as expected and does not pose a health risk to Canadians.

• What Do Radiation Measurements Mean?

April 2011 - Health Canada Fixed Point Network Daily Dose Summary (µSv/day)

Station	P/T	Baseline (2010)			1	2	3	4	5	6	7	8	9	10	11
		Min	Average	Max
x dose data for this date was not collected due to problems with equipment or data transfer
Calgary	AB	0.28	0.48	0.64	0.43	0.46	0.37	0.40	0.43	0.43	0.43	0.43	0.44	0.44	0.43
Victoria	BC	0.21	0.23	0.35	0.23	0.23	0.23	0.24	0.24	0.24	0.22	0.22	0.22	0.23	0.22
Vancouver	BC	0.07	0.44	0.59	0.43	0.42	0.43	0.46	0.43	0.43	0.43	0.43	0.43	0.44	0.44
Winnipeg	MB	0.31	0.38	1.06	0.38	0.37	0.40	0.35	0.36	0.37	0.37	0.38	0.42	0.38	0.37
Saint John	NB	0.56	0.68	0.78	0.68	0.64	0.67	0.68	0.72	0.69	0.68	0.67	0.68	0.68	0.69
St. John's	NL	0.49	0.68	0.76	0.53	0.57	0.59	0.59	0.61	0.63	0.64	0.63	0.63	0.64	0.64
Halifax	NS	0.10	0.80	0.92	0.82	0.83	0.83	0.80	0.83	0.83	0.81	0.80	0.83	0.82	0.82
Yellowknife	NWT	0.20	0.85	1.02	0.57	0.58	0.57	0.57	0.59	0.59	0.58	0.58	0.58	0.62	0.56
Thunder Bay	ON	0.39	0.46	1.04	0.43	0.45	0.49	0.52	0.44	0.44	0.43	0.44	0.44	0.45	0.50
Toronto	ON	0.08	0.28	0.53	0.25	0.26	0.26	0.33	0.28	0.26	0.26	0.25	0.27	0.30	0.28
Charlottetown	PEI	0.46	0.54	0.68	0.53	0.54	0.52	0.52	0.55	0.55	0.53	0.53	0.53	0.53	0.53
Montréal	QC	0.34	0.44	0.58	0.44	0.43	0.43	0.49	0.50	0.43	0.43	0.43	0.44	0.45	0.48
Regina	SK	0.44	0.76	1.06	0.35	0.36	0.36	0.33	0.35	0.34	0.34	0.34	0.34	0.36	0.36

April 2011 - Health Canada Fixed Point Network Daily Dose Summary (µSv/day)

Station	P/T	Baseline (2010)			12	13	14	15	16	17	18	19	20	21	22
		Min	Average	Max
x dose data for this date was not collected due to problems with equipment or data transfer
Calgary	AB	0.28	0.48	0.64	0.42	0.43	0.53	0.39	0.41	0.39	0.42	0.42	0.43	0.43	0.44
Victoria	BC	0.21	0.23	0.35	0.22	0.23	0.24	0.22	0.23	0.22	0.22	0.22	0.23	0.22	0.22
Vancouver	BC	0.07	0.44	0.59	0.42	0.43	0.44	0.43	0.43	0.43	0.44	0.44	0.43	0.43	0.43
Winnipeg	MB	0.31	0.38	1.06	0.37	0.35	0.35	0.35	0.36	0.35	0.35	0.36	0.37	0.39	0.40
Saint John	NB	0.56	0.68	0.78	0.69	0.68	0.70	0.67	0.67	0.69	0.69	0.68	0.70	0.68	0.68
St. John's	NL	0.49	0.68	0.76	0.68	0.65	0.65	0.66	0.65	0.66	0.66	0.67	0.66	0.65	0.64
Halifax	NS	0.10	0.80	0.92	0.81	0.80	0.81	0.80	0.82	0.83	0.81	0.87	0.84	0.84	0.82
Yellowknife	NWT	0.20	0.85	1.02	0.55	0.55	0.55	0.55	0.55	0.56	0.55	0.56	0.56	0.56	0.56
Thunder Bay	ON	0.39	0.46	1.04	0.45	0.44	0.42	0.42	0.44	0.42	0.42	x	0.43	0.43	0.43
Toronto	ON	0.08	0.28	0.53	0.25	0.26	0.26	0.24	0.31	0.28	0.25	0.25	0.32	0.24	0.25
Charlottetown	PEI	0.46	0.54	0.68	0.57	0.53	0.53	0.52	0.53	0.53	0.54	0.54	0.54	0.52	0.53
Montréal	QC	0.34	0.44	0.58	0.44	0.45	0.44	0.42	0.44	0.49	0.43	0.43	0.53	0.44	0.43
Regina	SK	0.44	0.76	1.06	0.38	0.39	0.41	0.43	0.46	0.44	0.45	0.47	0.50	0.54	0.55

April 2011 - Health Canada Fixed Point Network Daily Dose Summary (µSv/day)

Station	P/T	Baseline (2010)			23	24	25	26	27	28	29	30
		Min	Average	Max
x dose data for this date was not collected due to problems with equipment or data transfer
Calgary	AB	0.28	0.48	0.64	0.44	0.44	0.46	0.46	0.48	0.47	0.45	0.43
Victoria	BC	0.21	0.23	0.35	0.23	0.24	0.24	0.22	0.23	0.22	0.22	0.22
Vancouver	BC	0.07	0.44	0.59	0.43	0.45	0.44	0.43	0.43	0.44	0.43	0.42
Winnipeg	MB	0.31	0.38	1.06	0.38	0.39	0.37	0.37	0.38	0.37	0.38	0.53
Saint John	NB	0.56	0.68	0.78	0.68	0.69	0.69	0.71	0.69	0.68	0.68	0.69
St. John's	NL	0.49	0.68	0.76	0.66	0.67	0.66	0.66	0.65	0.66	0.65	0.66
Halifax	NS	0.10	0.80	0.92	0.82	0.84	0.82	0.86	0.82	0.82	0.82	0.82
Yellowknife	NWT	0.20	0.85	1.02	0.56	0.56	0.57	0.57	0.57	0.58	0.58	0.59
Thunder Bay	ON	0.39	0.46	1.04	0.45	0.46	0.45	0.44	0.47	0.43	0.45	0.48
Toronto	ON	0.08	0.28	0.53	0.33	0.27	0.28	0.30	0.28	0.29	0.26	0.25
Charlottetown	PEI	0.46	0.54	0.68	0.53	0.54	0.54	0.56	0.55	0.53	0.54	0.54
Montréal	QC	0.34	0.44	0.58	0.45	0.44	0.44	0.47	0.47	0.47	0.44	0.43
Regina	SK	0.44	0.76	1.06	0.59	0.62	0.68	0.70	0.73	0.77	0.77	0.75

April 2011 - Additional British Columbia and Yukon Fixed Point Daily Dose Summary (µSv/day)

Station	P/T	Baseline			1	2	3	4	5	6	7	8	9	10	11
		Min	Average	Max
Supplementary detectors deployed in March: The Min, Max and Median numbers are only based on the first 35 days of continuous operation of these systems so it is reasonable to expect that future values will be slightly below/above the current Min/Max values.
Prince Rupert	BC	0.41	0.42	0.45	0.42	0.42	0.42	0.44	0.43	0.42	0.42	0.42	0.43	0.42	0.42
Prince George	BC	0.56	0.59	0.62	0.56	0.59	0.59	0.58	0.59	0.58	0.58	0.59	0.59	0.59	0.59
Kamloops	BC	0.46	0.48	0.53	0.48	0.48	0.48	0.47	0.47	0.48	0.48	0.48	0.49	0.47	0.47
Burnaby	BC	0.47	0.49	0.54	0.48	0.48	0.48	0.54	0.50	0.48	0.48	0.48	0.48	0.50	0.48
Port Hardy	BC	0.25	0.26	0.29	0.25	0.26	0.26	0.26	0.28	0.28	0.25	0.25	0.26	0.27	0.27
Tofino	BC	0.32	0.33	0.37	0.32	0.32	0.33	0.34	0.34	0.34	0.33	0.33	0.33	0.34	0.33
Abbotsford	BC	0.28	0.29	0.31	0.28	0.28	0.28	0.31	0.29	0.29	0.28	0.28	0.28	0.29	0.28
Kelowna	BC	0.84	0.87	0.93	0.84	0.88	0.85	0.85	0.86	0.86	0.85	0.88	0.87	0.85	0.85
Whitehorse	YT	0.25	0.27	0.29	0.25	0.26	0.26	0.26	0.28	0.28	0.25	0.25	0.26	0.27	0.27

April 2011 - Additional British Columbia and Yukon Fixed Point Daily Dose Summary (µSv/day)

Station	P/T	Baseline			12	13	14	15	16	17	18	19	20	21	22
		Min	Average	Max
Supplementary detectors deployed in March: The Min, Max and Median numbers are only based on the first 35 days of continuous operation of these systems so it is reasonable to expect that future values will be slightly below/above the current Min/Max values.
Prince Rupert	BC	0.41	0.42	0.45	0.43	0.42	0.42	0.41	0.42	0.42	0.43	0.45	0.41	0.42	0.41
Prince George	BC	0.56	0.59	0.62	0.58	0.59	0.59	0.59	0.60	0.60	0.61	0.60	0.60	0.60	0.59
Kamloops	BC	0.46	0.48	0.53	0.47	0.48	0.47	0.46	0.48	0.48	0.49	0.49	0.47	0.49	0.48
Burnaby	BC	0.47	0.49	0.54	0.47	0.49	0.49	0.48	0.48	0.48	0.48	0.48	0.48	0.48	0.47
Port Hardy	BC	0.25	0.26	0.29	0.26	0.26	0.26	0.26	0.25	0.25	0.26	0.27	0.26	0.25	0.25
Tofino	BC	0.32	0.33	0.37	0.35	0.34	0.34	0.32	0.32	0.32	0.33	0.33	0.33	0.32	0.33
Abbotsford	BC	0.28	0.29	0.31	0.28	0.29	0.30	0.28	0.29	0.28	0.28	0.29	0.28	0.28	0.28
Kelowna	BC	0.84	0.87	0.93	0.85	0.88	0.86	0.86	0.86	0.86	0.88	0.86	0.86	0.87	0.85
Whitehorse	YT	0.25	0.27	0.29	0.26	0.26	0.26	0.26	0.25	0.25	0.26	0.27	0.26	0.25	0.25

April 2011 - Additional British Columbia and Yukon Fixed Point Daily Dose Summary (µSv/day)

Station	P/T	Baseline			23	24	25	26	27	28	29	30
		Min	Average	Max
Supplementary detectors deployed in March: The Min, Max and Median numbers are only based on the first 35 days of continuous operation of these systems so it is reasonable to expect that future values will be slightly below/above the current Min/Max values.
Prince Rupert	BC	0.41	0.42	0.45	0.41	0.42	0.43	0.41	0.41	0.41	0.41	0.41
Prince George	BC	0.56	0.59	0.62	0.61	0.62	0.60	0.60	0.59	0.60	0.59	0.59
Kamloops	BC	0.46	0.48	0.53	0.49	0.50	0.48	0.48	0.47	0.47	0.47	0.47
Burnaby	BC	0.47	0.49	0.54	0.48	0.49	0.49	0.48	0.48	0.48	0.48	0.47
Port Hardy	BC	0.25	0.26	0.29	0.25	0.27	0.27	0.25	0.26	0.25	0.25	0.25
Tofino	BC	0.32	0.33	0.37	0.33	0.35	0.33	0.32	0.33	0.33	0.32	0.32
Abbotsford	BC	0.28	0.29	0.31	0.28	0.29	0.30	0.28	0.28	0.29	0.28	0.28
Kelowna	BC	0.84	0.87	0.93	0.87	0.88	0.87	0.86	0.86	0.85	0.86	0.85
Whitehorse	YT	0.25	0.27	0.29	0.25	0.27	0.27	0.25	0.26	0.25	0.25	0.25

May 2011 - Weekly Dose Radiation Levels (µSv/day)

Given that there have not been any recent significant releases of radiation from Japan and the levels of radiation across Canada continue to be within normal background levels, Health Canada has changed the frequency of publishing the data from all monitoring networks on the website to a single day once a week starting the first week in May.

Summary: Data received is as expected and does not pose a health risk to Canadians.

• What Do Radiation Measurements Mean?

May 2011 - Health Canada Fixed Point Network Weekly Dose Summary (µSv/day)

Station	P/T	Baseline (2010)			May 4	May 11	May 18	May 25
		Min	Average	Max
x dose data for this date was not collected due to problems with equipment or data transfer
Calgary	AB	0.28	0.48	0.64	0.44	0.46	0.44	0.49
Abbotsford	BC	0.28	0.29	0.31	0.28	0.30	0.28	0.29
Burnaby	BC	0.47	0.49	0.54	0.47	0.49	0.48	0.49
Kamloops	BC	0.46	0.48	0.53	0.47	0.48	0.48	0.55
Kelowna	BC	0.84	0.87	0.93	0.86	0.88	0.87	0.92
Port Hardy	BC	0.25	0.26	0.29	0.25	0.26	0.25	0.26
Prince George	BC	0.56	0.59	0.62	0.59	0.62	0.59	0.61
Prince Rupert	BC	0.41	0.42	0.45	0.42	0.41	0.42	0.42
Tofino	BC	0.32	0.33	0.37	0.32	0.33	0.32	0.35
Victoria	BC	0.21	0.23	0.35	0.22	0.23	0.22	0.24
Vancouver	BC	0.07	0.44	0.59	0.43	0.44	0.43	0.44
Winnipeg	MB	0.31	0.38	1.06	0.42	0.37	0.37	0.37
Saint John	NB	0.56	0.68	0.78	0.67	0.67	0.68	0.68
St. John's	NL	0.49	0.68	0.76	0.65	0.65	0.66	0.66
Halifax	NS	0.10	0.80	0.92	0.82	0.80	0.81	0.82
Yellowknife	NWT	0.20	0.85	1.02	0.61	0.86	0.91	0.91
Thunder Bay	ON	0.39	0.46	1.04	0.46	0.46	0.45	0.44
Toronto	ON	0.08	0.28	0.53	0.29	0.25	0.29	0.25
Charlottetown	PEI	0.46	0.54	0.68	0.52	0.52	0.52	0.54
Montréal	QC	0.34	0.44	0.58	0.46	0.43	0.44	0.43
Regina	SK	0.44	0.76	1.06	0.77	0.76	0.82	0.76
Whitehorse	YT	0.25	0.27	0.29	0.25	0.26	0.25	0.26

June 2011 - Weekly Dose Radiation Levels (µSv/day)

Summary: Data received is as expected and does not pose a health risk to Canadians.

• What Do Radiation Measurements Mean?

June 2011 - Health Canada Fixed Point Network Weekly Dose Summary (µSv/day)

Station	P/T	Baseline (2010)			June 1	June 8	June 15	June 22	June 29
		Min	Average	Max
x dose data for this date was not collected due to problems with equipment or data transfer
Calgary	AB	0.28	0.48	0.64	0.45	0.46	0.47	0.45	0.47
Abbotsford	BC	0.28	0.29	0.31	0.30	0.28	0.28	0.29	0.30
Burnaby	BC	0.47	0.49	0.54	0.50	0.48	0.48	0.48	0.48
Kamloops	BC	0.46	0.48	0.53	0.50	0.49	0.47	0.48	0.48
Kelowna	BC	0.84	0.87	0.93	0.89	0.90	0.86	0.89	0.89
Port Hardy	BC	0.25	0.26	0.29	0.26	0.26	0.25	0.25	0.29
Prince George	BC	0.56	0.59	0.62	0.61	0.60	0.59	0.62	0.61
Prince Rupert	BC	0.41	0.42	0.45	0.42	0.41	0.41	0.41	0.42
Tofino	BC	0.32	0.33	0.37	0.34	0.33	0.33	0.33	0.33
Victoria	BC	0.21	0.23	0.35	0.23	0.23	0.22	0.23	0.23
Vancouver	BC	0.07	0.44	0.59	0.44	0.44	0.42	0.42	0.43
Winnipeg	MB	0.31	0.38	1.06	0.35	0.40	0.42	0.43	0.38
Saint John	NB	0.56	0.68	0.78	0.68	0.67	0.68	0.67	0.69
St. John's	NL	0.49	0.68	0.76	0.62	0.64	0.65	0.66	0.65
Halifax	NS	0.10	0.80	0.92	0.82	0.82	0.86	0.80	0.77
Yellowknife	NWT	0.20	0.85	1.02	0.90	0.90	0.89	0.91	0.94
Thunder Bay	ON	0.39	0.46	1.04	0.44	0.45	0.44	0.59	0.46
Toronto	ON	0.08	0.28	0.53	x	0.44	0.39	0.44	0.40
Charlottetown	PEI	0.46	0.54	0.68	0.53	0.53	0.53	0.52	0.54
Montréal	QC	0.34	0.44	0.58	0.45	0.47	0.44	0.44	0.46
Regina	SK	0.44	0.76	1.06	0.74	0.73	0.80	0.71	0.83
Whitehorse	YT	0.25	0.27	0.29	0.26	0.26	0.25	0.25	0.29

July 2011 - Weekly Dose Radiation Levels (µSv/day)

Summary: Data received is as expected and does not pose a health risk to Canadians.

• What Do Radiation Measurements Mean?

July 2011 - Health Canada Fixed Point Network Weekly Dose Summary (µSv/day)

Station	P/T	Baseline (2010)			July 6	July 13	July 20	July 27
		Min	Average	Max
x dose data for this date was not collected due to problems with equipment or data transfer
Calgary	AB	0.28	0.48	0.64	0.49	0.58	0.49	0.50
Abbotsford	BC	0.28	0.29	0.31	0.30	0.29	0.28	0.28
Burnaby	BC	0.47	0.49	0.54	0.48	0.48	0.48	0.48
Kamloops	BC	0.46	0.48	0.53	0.48	0.49	0.48	0.49
Kelowna	BC	0.84	0.87	0.93	0.89	0.90	0.86	0.86
Port Hardy	BC	0.25	0.26	0.29	0.29	0.27	0.25	0.25
Prince George	BC	0.56	0.59	0.62	0.61	0.65	0.59	0.59
Prince Rupert	BC	0.41	0.42	0.45	0.42	0.41	0.42	0.41
Tofino	BC	0.32	0.33	0.37	0.33	0.34	0.32	0.33
Victoria	BC	0.21	0.23	0.35	0.23	0.23	0.22	0.22
Vancouver	BC	0.07	0.44	0.59	0.43	0.44	0.42	0.41
Winnipeg	MB	0.31	0.38	1.06	0.39	0.38	0.42	0.40
Saint John	NB	0.56	0.68	0.78	0.69	0.70	0.69	0.70
St. John's	NL	0.49	0.68	0.76	0.66	0.67	0.66	0.67
Halifax	NS	0.10	0.80	0.92	0.78	0.82	0.82	0.82
Yellowknife	NWT	0.20	0.85	1.02	0.87	0.91	0.89	0.91
Thunder Bay	ON	0.39	0.46	1.04	0.45	0.44	0.53	0.45
Toronto	ON	0.08	0.28	0.53	0.44	0.41	0.42	0.41
Charlottetown	PEI	0.46	0.54	0.68	0.55	0.55	0.55	0.55
Montréal	QC	0.34	0.44	0.58	0.47	0.44	0.46	0.45
Regina	SK	0.44	0.76	1.06	0.83	0.84	0.92	0.84
Whitehorse	YT	0.25	0.27	0.29	0.29	0.27	0.25	0.25

August 2011 - Weekly Dose Radiation Levels (µSv/day)

Summary: Data received is as expected and does not pose a health risk to Canadians.

• What Do Radiation Measurements Mean?

August 2011 - Health Canada Fixed Point Network Weekly Dose Summary (µSv/day)

Station	P/T	Baseline (2010)			August 3	August 10	August 17	August 24	August 31
		Min	Average	Max
x: the detector for this location is no longer available
Calgary	AB	0.28	0.48	0.64	0.48	0.51	0.461	0.49	0.56
Abbotsford	BC	0.28	0.29	0.31	0.29	0.28	0.29	0.29	0.28
Burnaby	BC	0.47	0.49	0.54	0.48	0.48	0.49	0.48	0.49
Kamloops	BC	0.46	0.48	0.53	0.50	0.48	0.49	0.48	0.48
Kelowna	BC	0.84	0.87	0.93	0.89	0.88	0.89	0.91	0.89
Port Hardy	BC	0.25	0.26	0.29	0.25	x	x	x	x
Prince George	BC	0.56	0.59	0.62	0.61	0.66	x	x	x
Prince Rupert	BC	0.41	0.42	0.45	0.42	0.41	x	x	x
Tofino	BC	0.32	0.33	0.37	0.33	x	x	x	x
Victoria	BC	0.21	0.23	0.35	0.23	0.23	0.23	0.23	0.23
Vancouver	BC	0.07	0.44	0.59	0.43	0.43	0.43	0.46	0.45
Winnipeg	MB	0.31	0.38	1.06	0.43	0.40	0.39	0.40	0.44
Saint John	NB	0.56	0.68	0.78	0.68	0.73	0.69	0.68	0.68
St. John's	NL	0.49	0.68	0.76	0.66	0.66	0.68	0.67	0.68
Halifax	NS	0.10	0.80	0.92	0.89	0.83	0.81	0.78	0.78
Yellowknife	NWT	0.20	0.85	1.02	0.86	0.91	0.89	0.88	0.91
Thunder Bay	ON	0.39	0.46	1.04	0.47	0.45	0.50	0.49	0.48
Toronto	ON	0.08	0.28	0.53	0.51	0.42	0.41	0.46	0.43
Charlottetown	PEI	0.46	0.54	0.68	0.54	0.53	0.55	0.54	0.54
Montréal	QC	0.34	0.44	0.58	0.45	0.55	0.44	0.45	0.44
Regina	SK	0.44	0.76	1.06	0.93	0.89	0.89	0.88	1.03
Whitehorse	YT	0.25	0.27	0.29	0.25	x	x	x	x

September 2011 - Weekly Dose Radiation Levels (µSv/day)

Summary: Data received is as expected and does not pose a health risk to Canadians.

• What Do Radiation Measurements Mean?

September 2011 - Health Canada Fixed Point Network Weekly Dose Summary (µSv/day)

Station	P/T	Baseline (2010)			September 7	September 14	September 21	September 28
		Min	Average	Max
x dose data for this date was not collected due to problems with equipment or data transfer
Calgary	AB	0.28	0.48	0.64	0.48
Abbotsford	BC	0.28	0.29	0.31	0.29
Burnaby	BC	0.47	0.49	0.54	0.49
Kamloops	BC	0.46	0.48	0.53	0.51
Kelowna	BC	0.84	0.87	0.93	0.92
Port Hardy	BC	0.25	0.26	0.29	x
Prince George	BC	0.56	0.59	0.62	x
Prince Rupert	BC	0.41	0.42	0.45	x
Tofino	BC	0.32	0.33	0.37	x
Victoria	BC	0.21	0.23	0.35	0.24
Vancouver	BC	0.07	0.44	0.59	0.44
Winnipeg	MB	0.31	0.38	1.06	0.47
Saint John	NB	0.56	0.68	0.78	0.68
St. John's	NL	0.49	0.68	0.76	0.67
Halifax	NS	0.10	0.80	0.92	0.80
Yellowknife	NWT	0.20	0.85	1.02	0.89
Thunder Bay	ON	0.39	0.46	1.04	0.51
Toronto	ON	0.08	0.28	0.53	0.41
Charlottetown	PEI	0.46	0.54	0.68	0.53
Montréal	QC	0.34	0.44	0.58	0.44
Regina	SK	0.44	0.76	1.06	0.90
Whitehorse	YT	0.25	0.27	0.29	x

Comprehensive Nuclear Test Ban Treaty Network Stations

Health Canada's CTBT monitoring stations, which are part of a global Comprehensive Nuclear Test Ban Treaty monitoring network, are highly sensitive and capable of detecting a broad range of isotopes at low concentrations. The measurements in the following charts show the concentrations of the principal isotopes of interest coming from the damaged reactors that were detected in the first few weeks of the emergency.

Five stations across Canada are equipped to detect and measure isotopes in particulate form. Data for cesium-137, iodine-131, and tellurium-132 are reported in milliBecquerels per cubic meter (mBq/m³).

In addition, Yellowknife, Ottawa, and St John's are equipped to collect data for xenon-133, which is a noble gas. Noble gases do not react with other elements in the environment. As a result, they can travel long distances in the atmosphere which makes them good tracers to follow the movements of atmospheric contamination. Xenon-133 measurements are reported in Becquerels per cubic meter (Bq/m³). The contribution of Xenon-133 to total radiation dose is minimal and does not pose any health risk.

Note: There is a lag time for posting data from this network of stations as the radioactivity is measured over a longer period of time and then must be analyzed.

March 2011 - Radiation Concentration (mBq/m³ and Bq/m³)

Summary: Data received indicates no health risks to Canadians

• What Do Radiation Measurements Mean?

March 2011 - Canadian Comprehensive Nuclear-Test-Ban Treaty Station Radioisotope Concentrations

Station	P/T	Radioisotope	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Sidney	BC	Xe-133 (Bq/m³)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
		Te-132 (mBq/m³)	-	0.22	0.35	0.69	0.38	0.15	0.20	0.24	0.35	0.07	0.04	0.01	0.01	0.01	-
		I-131 (mBq/m³)	-	0.55	1.91	3.63	2.75	1.29	1.14	1.64	2.74	0.51	0.63	0.39	0.26	0.28	-
		Cs-137 (mBq/m³)	-	0.03	0.09	0.21	0.15	0.09	0.11	0.15	0.40	0.11	0.06	0.01	0.01	0.02	-
St. John's	NL	Xe-133 (Bq/m³)	-	-	-	0.00	0.00	0.00	0.01	0.05	0.08	0.16	0.05	0.09	0.15	0.16	1.2
		Te-132 (mBq/m³)	-	-	-	-	-	-	-	0.19	-	-	-	0.00	-	-	0.01
		I-131 (mBq/m³)	-	-	0.00	-	-	-	0.08	0.15	-	0.38	0.50	0.27	0.14	0.11	0.57
		Cs-137 (mBq/m³)	-	-	-	-	-	-	0.00	0.00	-	-	0.00	0.00	0.00	-	0.05
Yellowknife	NWT	Xe-133 (Bq/m³)	-	-	0.00	0.00	0.00	0.00	0.31	0.69	2.18	0.65	1.26	1.34	1.21	1.06	1.85
		Te-132 (mBq/m³)	-	-	-	-	-	-	0.02	0.01	0.09	0.01	0.03	0.01	0.02	0.02	0.04
		I-131 (mBq/m³)	-	-	-	-	0.00	-	0.32	0.63	2.29	0.74	1.33	0.79	1.02	0.99	1.21
		Cs-137 (mBq/m³)	-	-	-	-	-	-	0.02	0.02	0.12	-	0.06	0.04	0.06	0.07	0.17
Resolute Bay	NU	Xe-133 (Bq/m³)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
		Te-132 (mBq/m³)	-	-	-	-	-	-	-	0.00	0.00	0.08	0.01	-	-	-	0.01
		I-131 (mBq/m³)	-	-	-	-	1.16	2.77	1.08	0.40	1.60	1.13	3.12	6.93	9.76	4.51	3.66
		Cs-137 (mBq/m³)	-	-	-	-	-	-	-	0.00	0.01	0.08	0.05	-	-	0.05	0.06
Ottawa	ON	Xe-133 (Bq/m³)	0.01	0.00	0.16	0.04	-	0.10	-	0.01	0.05	0.11	0.06	0.29	1.87	1.94	3.64
		Te-132 (mBq/m³)	-	-	-	-	0.01	0.05	0.01	0.00	-	-	0.00	-	-	0.02	0.02
		I-131 (mBq/m³)	-	-	0.01	-	0.25	4.26	1.43	1.19	0.78	0.47	0.72	0.39	1.18	0.80	0.80
		Cs-137 (mBq/m³)	-	-	-	-	-	0.04	0.01	0.00	0.00	-	0.00	0.00	0.07	0.10	0.10

April 2011 - Radiation Concentration (mBq/m³ and Bq/m³)

Please note that starting April 1, 2011 the following charts will only be updated 3 times a week; however, Health Canada will continue to monitor the data on a daily basis.

Summary: Data received indicates no health risks to Canadians

• What Do Radiation Measurements Mean?

April 2011 - Canadian Comprehensive Nuclear-Test-Ban Treaty Station Radioisotope Concentrations

Station	P/T	Radioisotope	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
blank: data not available at the time of publishing - : not detected < 0.01: less than 0.01
Sidney	BC	Xe-133 (Bq/m³)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
		Te-132 (mBq/m³)	< 0.01	< 0.01	0.01	0.01	< 0.01	< 0.01	< 0.01	< 0.01	-	< 0.01	-	-	-	-	-
		I-131 (mBq/m³)	0.09	0.12	0.44	0.50	0.08	0.13	0.20	0.10	-	0.08	0.03	0.06	0.05	0.08	0.07
		Cs-137 (mBq/m³)	< 0.01	0.01	0.06	0.11	0.21	0.04	0.09	0.05	-	0.04	0.02	0.02	0.02	0.02	0.03
St. John's	NL	Xe-133 (Bq/m³)	1.86	1.35	1.51	3.51	2.29	1.73	1.17	-	-	-	0.76	0.62	0.47	0.45	0.30
		Te-132 (mBq/m³)	0.01	< 0.01	< 0.01	0.03	0.07	0.01	0.01	0.02	0.01	0.01	0.01	< 0.01	-	< 0.01	-
		I-131 (mBq/m³)	0.42	0.14	0.20	0.94	2.17	0.39	0.44	0.50	0.71	0.81	0.40	0.22	0.14	0.30	0.02
		Cs-137 (mBq/m³)	0.04	0.02	0.04	0.26	0.92	0.11	0.22	0.35	0.29	0.30	0.29	0.18	0.05	0.12	0.01
Yellowknife	NWT	Xe-133 (Bq/m³)	2.05	2.38	1.42	1.30	1.30	1.32	1.15	-	-	-	-	-	-	-	-
		Te-132 (mBq/m³)	0.04	0.04	0.01	0.02	0.01	0.01	0.01	0.01	< 0.01	< 0.01	< 0.01	< 0.01	0.01	-	0.01
		I-131 (mBq/m³)	1.34	1.72	2.15	2.37	1.96	1.07	1.28	0.74	0.34	0.72	1.00	1.17	1.07	0.70	1.00
		Cs-137 (mBq/m³)	0.22	0.30	0.11	0.14	0.16	0.13	0.13	0.13	0.08	0.12	0.15	0.16	0.36	0.20	0.46
Resolute Bay	NU	Xe-133 (Bq/m³)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
		Te-132 (mBq/m³)	0.18	0.02	0.02	0.02	0.01	< 0.01	< 0.01	-	< 0.01	-	-	-	-	-	-
		I-131 (mBq/m³)	5.03	3.86	7.35	3.14	2.36	1.31	1.32	1.36	1.93	1.37	2.14	1.93	1.23	0.67	0.87
		Cs-137 (mBq/m³)	0.81	0.10	0.16	0.18	0.10	0.07	0.10	0.06	0.10	0.12	0.16	0.13	0.09	0.08	0.15
Ottawa	ON	Xe-133 (Bq/m³)	2.99	2.37	2.52	-	-	-	-	-	-	0.96	0.57	0.39	0.43	0.39	0.35
		Te-132 (mBq/m³)	0.06	0.04	0.04	0.02	0.01	0.01	0.01	0.01	-	-	< 0.01	-		< 0.01	-
		I-131 (mBq/m³)	2.61	1.66	3.10	2.14	0.48	0.48	1.11	1.05	-	-	0.37	0.05	0.38	0.13	-
		Cs-137 (mBq/m³)	0.25	0.26	0.27	0.21	0.07	0.11	0.24	0.24	-	-	0.10	0.01	0.12	0.06	-

April 2011 - Canadian Comprehensive Nuclear-Test-Ban Treaty Station Radioisotope Concentrations

Station	P/T	Radioisotope	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
blank: data not available at the time of publishing - : not detected < 0.01: less than 0.01
Sidney	BC	Xe-133 (Bq/m³)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
		Te-132 (mBq/m³)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
		I-131 (mBq/m³)	0.07	0.07	0.04	0.04	0.04	0.03	0.03	0.07	0.06	0.03	0.01	< 0.01	0.01	0.01	0.01
		Cs-137 (mBq/m³)	0.05	0.04	0.02	0.02	0.04	0.02	0.02	0.06	0.04	0.02	< 0.01	< 0.01	< 0.01	< 0.01	< 0.01
St. John's	NL	Xe-133 (Bq/m³)	0.28	0.31	0.26	0.18	0.17	0.16	0.14	0.13	0.10	0.09	0.07	0.07	0.06	0.05	0.03
		Te-132 (mBq/m³)	< 0.01		-	-	-	-	-	-	-	-	-	-	-	-	-
		I-131 (mBq/m³)	0.56	0.46	0.17	0.02	0.06	0.05	0.02	0.14	0.08	< 0.01	0.02	0.02	0.01	0.01	-
		Cs-137 (mBq/m³)	0.30	0.36	0.22	0.01	0.09	0.05	0.03	0.13	0.10	0.06	0.02	0.02	0.02	-	-
Yellowknife	NWT	Xe-133 (Bq/m³)	-	-	0.24	0.21	0.15	0.13	0.12	0.12	0.12	-	-	0.07	0.06	0.05	0.05
		Te-132 (mBq/m³)	< 0.01	< 0.01	< 0.01	-	-	-	-	-	-	-	-	-	-	-	-
		I-131 (mBq/m³)	0.93	0.60	0.60	0.23	0.15	0.44	0.47	0.23	0.26	0.39	0.13	0.09	0.05	0.04	0.05
		Cs-137 (mBq/m³)	0.36	0.30	0.30	0.20	0.09	0.13	0.19	0.15	0.17	0.23	0.16	0.09	0.07	0.03	0.04
Resolute Bay	NU	Xe-133 (Bq/m³)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
		Te-132 (mBq/m³)	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
		I-131 (mBq/m³)	0.87	1.01	0.79	0.88	0.67	0.54	0.36	0.29	0.46	0.37	-	0.30	0.14	0.18	0.10
		Cs-137 (mBq/m³)	0.24	0.23	0.16	0.29	0.31	0.30	0.19	0.13	0.26	0.28	-	0.20	0.11	0.21	0.15
Ottawa	ON	Xe-133 (Bq/m³)	0.33	-	-	-	-	1.10	-	0.14	0.12	0.13	-	-	-	-	-
		Te-132 (mBq/m³)	-	-	< 0.01	-	-	-	-	-	-	-	-	-	-	-	-
		I-131 (mBq/m³)	-	-	0.20	0.10	0.11	0.03	0.04	-	-	-	-	0.01	< 0.01	< 0.01	-
		Cs-137 (mBq/m³)	-	-	0.16	0.14	0.09	0.03	0.05	-	-	-	-	0.02	0.01	< 0.01	-

May 2011 - Weekly Radiation Concentration (mBq/m³ and Bq/m³)

Given that there have not been any recent significant releases of radiation from Japan and the levels of radiation across Canada continue to be within normal background levels, Health Canada has changed the frequency of publishing the data from all monitoring networks on the Website to a single day once a week starting the first week in May 2011.

Summary: Data received indicates no health risks to Canadians

• What Do Radiation Measurements Mean?

May 2011 - Canadian Comprehensive Nuclear-Test-Ban Treaty Station Radioisotope Weekly Concentrations

Station	P/T	Radioisotope	4	11	18	25
blank: data not available at the time of publishing - : not detected < 0.01: less than 0.01
Sidney	BC	Xe-133 (Bq/m³)	-	-	-	-
		Te-132 (mBq/m³)	-	-	-	-
		I-131 (mBq/m³)	0.01	-	< 0.01	-
		Cs-137 (mBq/m³)	0.01	-	< 0.01	< 0.01
St. John's	NL	Xe-133 (Bq/m³)	0.03	0.01	0.01	-
		Te-132 (mBq/m³)	-	-	-	-
		I-131 (mBq/m³)	0.01	-	-	< 0.01
		Cs-137 (mBq/m³)	0.01	-	-	< 0.01
Yellowknife	NWT	Xe-133 (Bq/m³)	0.03	0.01	0.01	-
		Te-132 (mBq/m³)	-	-	-	-
		I-131 (mBq/m³)	0.03	< 0.01	< 0.01	< 0.01
		Cs-137 (mBq/m³)	0.04	0.01	< 0.01	< 0.01
Resolute Bay	NU	Xe-133 (Bq/m³)	-	-	-	-
		Te-132 (mBq/m³)	-	-	-	-
		I-131 (mBq/m³)	0.12	-	0.02	0.01
		Cs-137 (mBq/m³)	0.09	-	0.02	< 0.01
Ottawa	ON	Xe-133 (Bq/m³)	-	-	-	-
		Te-132 (mBq/m³)	-	-	-	-
		I-131 (mBq/m³)	< 0.01	< 0.01	< 0.01	-
		Cs-137 (mBq/m³)	0.01	-	-	-

June 2011 - Weekly Radiation Concentration (mBq/m³ and Bq/m³)

Data for Xe-133 from Japan is below reporting levels and no longer appears in the table.

Summary: Data received indicates no health risks to Canadians

• What Do Radiation Measurements Mean?

June 2011 - Canadian Comprehensive Nuclear-Test-Ban Treaty Station Radioisotope Weekly Concentrations

Station	P/T	Radioisotope	1	8	15	22	29
blank: data not available at the time of publishing - : not detected < 0.01: less than 0.01
Sidney	BC	Te-132 (mBq/m³)	-	-	-	-	-
		I-131 (mBq/m³)	-	-	-	-	-
		Cs-137 (mBq/m³)	-	< 0.01	-	-	-
St. John's	NL	Te-132 (mBq/m³)	-	-	-	-	-
		I-131 (mBq/m³)	-	-	-	-	-
		Cs-137 (mBq/m³)	< 0.01	-	-	-	-
Yellowknife	NWT	Te-132 (mBq/m³)	-	-	-	-	-
		I-131 (mBq/m³)	-	-	-	-	-
		Cs-137 (mBq/m³)	< 0.01	-	-	-	-
Resolute Bay	NU	Te-132 (mBq/m³)	-	-	-	-	-
		I-131 (mBq/m³)	-	-	-	-	-
		Cs-137 (mBq/m³)	-	< 0.01	-	-	-
Ottawa	ON	Te-132 (mBq/m³)	-	-	-	-	-
		I-131 (mBq/m³)	-	-	-	-	-
		Cs-137 (mBq/m³)	< 0.01	-	-	-	-

July 2011 - Weekly Radiation Concentration (mBq/m³ and Bq/m³)

Summary: Data received indicates no health risks to Canadians

• What Do Radiation Measurements Mean?

July 2011 - Canadian Comprehensive Nuclear-Test-Ban Treaty Station Radioisotope Weekly Concentrations

Station	P/T	Radioisotope	6	13	20	27
blank: data not available at the time of publishing - : not detected < 0.01: less than 0.01
Sidney	BC	Te-132 (mBq/m³)	-	-	-	-
		I-131 (mBq/m³)	-	-	-	-
		Cs-137 (mBq/m³)	-	-	-	-
St. John's	NL	Te-132 (mBq/m³)	-	-	-	-
		I-131 (mBq/m³)	-	-	-	-
		Cs-137 (mBq/m³)	-	-	-	-
Yellowknife	NWT	Te-132 (mBq/m³)	-	-	-	-
		I-131 (mBq/m³)	-	-	-	-
		Cs-137 (mBq/m³)	-	-	-	-
Resolute Bay	NU	Te-132 (mBq/m³)	-	-	-	-
		I-131 (mBq/m³)	-	-	-	-
		Cs-137 (mBq/m³)	-	-	-	-
Ottawa	ON	Te-132 (mBq/m³)	-	-	-	-
		I-131 (mBq/m³)	-	-	-	-
		Cs-137 (mBq/m³)	-	-	-	-

August 2011 - Weekly Radiation Concentration (mBq/m³ and Bq/m³)

Summary: Data received indicates no health risks to Canadians

• What Do Radiation Measurements Mean?

August 2011 - Canadian Comprehensive Nuclear-Test-Ban Treaty Station Radioisotope Weekly Concentrations

Station	P/T	Radioisotope	3	10	17	24	31
blank: data not available at the time of publishing - : not measured or not detected x: data for this date was not collected due to problems with equipment < 0.01: less than 0.01
Sidney	BC	Te-132 (mBq/m³)	x	x	-	-	< 0.01
		I-131 (mBq/m³)	x	x	-	-	-
		Cs-137 (mBq/m³)	x	x	-	-	-
St. John's	NL	Te-132 (mBq/m³)	-	-	-	-	-
		I-131 (mBq/m³)	-	-	-	-	-
		Cs-137 (mBq/m³)	-	-	-	-	-
Yellowknife	NWT	Te-132 (mBq/m³)	-	-	-	-	-
		I-131 (mBq/m³)	-	-	-	-	< 0.01
		Cs-137 (mBq/m³)	-	< 0.01	-	-	-
Resolute Bay	NU	Te-132 (mBq/m³)	-	-	-	-	-
		I-131 (mBq/m³)	-	-	-	-	-
		Cs-137 (mBq/m³)	-	< 0.01	-	-	-
Ottawa	ON	Te-132 (mBq/m³)	-	-	-	-	-
		I-131 (mBq/m³)	-	-	-	-	-
		Cs-137 (mBq/m³)	-	< 0.01	-	-	-

September 2011 - Weekly Radiation Concentration (mBq/m³ and Bq/m³)

Summary: Data received indicates no health risks to Canadians

• What Do Radiation Measurements Mean?

September 2011 - Canadian Comprehensive Nuclear-Test-Ban Treaty Station Radioisotope Weekly Concentrations

Station	P/T	Radioisotope	7	14	21	28
x: air concentration data for this date was not collected due to problems with equipment blank: data not available at the time of publishing - : not detected < 0.01: less than 0.01
Sidney	BC	Te-132 (mBq/m³)	-
		I-131 (mBq/m³)	-
		Cs-137 (mBq/m³)	-
St. John's	NL	Te-132 (mBq/m³)	-
		I-131 (mBq/m³)	-
		Cs-137 (mBq/m³)	-
Yellowknife	NWT	Te-132 (mBq/m³)	-
		I-131 (mBq/m³)	-
		Cs-137 (mBq/m³)	-
Resolute Bay	NU	Te-132 (mBq/m³)	-
		I-131 (mBq/m³)	-
		Cs-137 (mBq/m³)	-
Ottawa	ON	Te-132 (mBq/m³)	-
		I-131 (mBq/m³)	-
		Cs-137 (mBq/m³)	-