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Ionising radiation

Environmental Radioactivity - Medicine - Occupational Radiation Protection - Nuclear Hazards Defence

Ionisierende Strahlung

Air monitoring at Schauinsland measuring station

  • As part of air monitoring and trace analysis, the Federal Office for Radiation Protection (BfS) measures the activity concentrations of radioactive substances in the air.
  • In air monitoring, natural and artificial radionuclides from the atmosphere are measured continuously; the results are available within a few hours.
  • In trace analysis, minute traces of radioactive substances are detected. For that purpose, airborne dust is collected in large-area filters over seven days, measured and then analysed.

In order to measure the activity concentrations of radioactive substances in the air, the Federal Office for Radiation Protection (BfS) uses two methods: air monitoring and trace analysis.

In air monitoring, natural and artificial radionuclides from the atmosphere are measured continuously with measurement systems. The measurement results from these methods are available within only a few hours. In trace analysis, airborne dust is collected in large-area filters over seven days, measured and then analysed in order to detect even minute traces of radioactive substances. The measurement results are available several days after the end of the sampling period.

In comparison to trace analysis, the sensitivity of air monitoring is clearly lower; however, a considerably higher temporal resolution is achieved.

Activity concentration of naturally occurring radon and the calculated proportion of artificial beta activity

Measurement results from Schauinsland measuring station show the activity concentration of naturally occurring radon and the calculated proportion of artificial beta activity.

Current measurement results

Current measurement results from air monitoring

Natural radioactivity in the air is mainly produced by the radioactive noble gas radon and its daughter nuclides. The noble gas radon diffuses from the ground into the air. The concentration varies greatly depending on the weather conditions.

The measurement systems used for air monitoring are capable of distinguishing between this natural radioactivity and additional artificial radioactivity (see first figure). A radioactive cloud with artificial radioactive substances like after Chernobyl would be identified by a significant rise in the pink-coloured curve.

Air monitoring artificially Air monitoring artificiallyCalculated artificial proportion of the beta activity concentration measured at Schauinsland measuring station. This graph is updated every week.

The slight fluctuations in the pink-coloured curve result from the calculation method and are shown magnified once again in the second figure. These fluctuations are inherent to the measurement process and demonstrate that the system is functioning correctly. The negative values occur from the calculation due to statistical fluctuations. They do not constitute a measurement error.

In semi-automated systems, so-called fixed filter systems, the filter has to be changed by hand periodically in order to prevent it from clogging. These filter changes result in the regular data gaps observable in the diagrams.

In fully automated systems, so-called moving filter systems, a filter tape is automatically advanced within a particular time interval.

Results relating to the incident in Fukushima 2011

Air monitoring results relating to the incident in Fukushima

The figures show the air monitoring results at Schauinsland measuring station for the period from 21 March to 12 May 2011.

Share of artificial radioactivity after the reactor disaster in Fukushima 2011 Air monitoring FukushimaCalculated artificial proportion of the beta activity concentration measured at Schauinsland measuring station for the period from 21 March - 12 May 2011

From March to May 2011, very small amounts of artificial radionuclides from Fukushima were measured using trace analysis on Mt. Schauinsland. These activity concentrations are not detectable with air monitoring methods. They are extremely low compared to the naturally occurring radioactivity in the air which is continuously at a few becquerels per cubic metre of outdoor air in Germany.

State of 2017.10.30

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