Measurement results for radioactivity in outdoor air
This web page displays the results of measurements of radioactivity in outdoor air in Finland. The radioactive isotope of cesium, Cs-137, which is detected on a regular basis, has mainly originated from the accident at the Chernobyl nuclear power plant in 1986. Release from the March 2011 Fukushima nuclear power plant accident was transported across the northern hemisphere and raised the cesium activity concentrations temporarily also in Finland.
Besides Cs-137, also other radioactive substances released from the Fukushima power plant were detected in Finland. Radioactive iodine I-131 activity concentration in Helsinki is shown on STUK's Fukushima page. The table at the end of the page summarizes detections of other man-made nuclides not originating from the Fukushima power plant accident.
The unit of measurement used for the activity concentration in the graphs and table below is micro-Becquerel per cubic meter of air (?Bq/m3). An activity concentration of one ?Bq/m3 means, that on average, one radioactive atom decays in one cubic meter of air per one million seconds (11.6 days). For example, the average activity concentration of radon in the indoor air of Finnish homes is 120 Becquerels per cubic meter, i.e. 100 million times higher than typical concentrations of artificial radioactivity detected in outdoor air.
Measurement results for Cs-137
Other unusual observations
Other artificial radioactive substances that have been observed by the particle monitoring stations during the past years. Older detections are listed here.
| 6.2. – 16.2.2012 | Imatra | I-131 | 0.80 (36) |
| 6.2. – 14.2.2012 | Kotka | I-131 Co-60 | 0.23 (33) 0.23 (12) |
| 4.2. – 5.2. 2012 | Helsinki | I-131 | 1.29 (29) |
| 2.2. – 4.2. 2012 | Helsinki | I-131 | 1.11 (15) |
| 27.1. – 29.1.2012 | Helsinki | I-131 | 1.01 (21) |
| 25.1. – 27.1.2012 | Helsinki | I-131 | 1.22 (15) |
| 21.1. – 23.1.2012 | Helsinki | I-131 | 0.54 (27) |
| 19.1 – 23.1.2012 | Kuopio | I-131 | 1.25 (26) |
| 6.2. – 13.2.2012 | Ivalo | I-131 | 0.49 (12) |
| 16.1. – 23.1.2012 | Ivalo | I-131 | 0.61 (27) |
| 23.1. – 30.1. 2012 | Sodankylä | I-131 | 0.66 (30) |
| 16.1. – 23.1.2012 | Sodankylä | I-131 | 0.69 (24) |
| 13.2. – 20.2.2012 | Rovaniemi | I-131 | 0.099 (6) |
| 6.2. – 13.2.2012 | Rovaniemi | I-131 | 0.19 (30) |
| 23.1. – 30.1. 2012 | Rovaniemi | I-131 | 1.56 (29) |
| 16.1. – 23.1.2012 | Rovaniemi | I-131 | 0.25 (14) |
| 16.1. – 23.1.2012 | Kajaani | I-131 | 0.49(15) |
| 16.1. – 23.1.2012 | Imatra | I-131 | 1.13 (20) |
| 30.1. – 6.2.2012 | Kotka | I-131 | 0.35 (15) |
| 23.1. – 30.1. 2012 | Kotka | I-131 | 0.44 (12) |
| 9.1. – 23.1. 2012 | Kotka | I-131 | 0.15 (16) |
| 2.8. –19.8.2011 | Kotka | Fe-59 Co-58 Co-60 | 0.34(9) 0.22(10) 0.09(17) |
| 18.7. –25.7.2011 | Kotka | Co-60 | 0.2(21) |
| 8.6. – 9.6.2011 | Helsinki | Co-60 Mn-54 Fe-59 | 0.5 (28%) 2.4 (12%) 3.6 (10%) |
| 30.5. – 7.6.2011 | Kotka | Co-60 Mn-54 | 0.14 (16%) 0.11 (20%) |
| 9.5. – 25.5.2011 | Kotka | Co-60 | 0.09 (15%) |
| 31.1. – 2.2.2011 | Helsinki | Tc-99M | 3.1 (7%) |
| 22.12. – 23.12.2010 | Helsinki | Am-241 | single particle, activity 1.0 Bq (5 %) |
| 7.8. – 9.8.2010 | Helsinki | Co-60 | 6.4 (6%) |
| 12.7. – 26.7.2010 | Kotka | Co-60 | 8.5 (16%) |
| 30.3. – 6.4.2010 | Kotka | Co-60 | 2.0 (17%) |
| 4.1. – 11.1.2010 | Rovaniemi | Mn-54 | 0.06 (20%) |
| 4.1. – 11.1.2010 | Rovaniemi | Co-60 | 0.05 (30%) |
