radon map of switzerland - nucleus documents/radiation... · federal office of public health foph...

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

Radon Map of Switzerland

Experience in Switzerland

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016




2

Current Radon Map



May 25, 2016




3

Radon measurements 1994-2015 (in living spaces)



May 25, 2016




4

Radon Map 2004



May 25, 2016




5

Mean value of the community, based on the annual average

of all measured dwellings:

− Rn < 100 Bq/m3 = low risk area

− 100 Bq/m3 ≤ Rn < 200 Bq/m3 = medium risk area

− Rn ≥ 200 Bq/m3 = high risk area

Classification of communities



May 25, 2016




6

Consequences of the community based classification

Canton Neuchâtel

Canton Basel-Land



May 25, 2016




7

Misinterpretation of the radon map

• a specific buildings cannot be evaluated using the radon map

• neighboring buildings can exhibit very different radon situations

• the map can lead to a false sense of security



May 25, 2016




8

Radon prone areas Alps & Jura~2% of dwellings~1% of new dwellings

>1000 Bq/m3

All Switzerland is concerned !~12% of dwellings~6% of new dwellings

>300 Bq/m3

New situation



May 25, 2016




9

2% 12%

New map, the entire country is a radon prone area



May 25, 2016




10

New Radon Map – new approach

Project by Georg Kropat

Institute of radiophysics, Lausanne, Switzerland

Kropat, G., Bochud, F., Jaboyedoff, M., Laedermann, J.-P., Murith, C., Palacios, M., Baechler, S., 2014Major influencing factors of indoor radon concentrations in Switzerland.

Journal of Environmental Radioactivity 129, 7–22

Kropat, G., Baechler, S., Bailat, C., Barazza, F., Bochud, F., Damet, J., Meyer, N., Palacios (Gruson), M., Butterweck, G., 2015.CALIBRATION OF THE POLITRACK® SYSTEM BASED ON CR39 SOLID STATE NUCLEAR

TRACK DETECTORS FOR PASSIVE INDOOR RADON CONCENTRATION MEASUREMENTS.

Radiation Protection Dosimetry 167, 302 - 305

Kropat, G., Bochud, F., Jaboyedoff, M., Laedermann, J.-P., Murith, C., Palacios (Gruson), M., Baechler, S., 2015Predictive analysis and mapping of indoor radon concentrations in a complex environment using

kernel estimation: An application to Switzerland.

Science of the Total Environment 505, 137–148

Kropat, G., Bochud, F., Jaboyedoff, M., Laedermann, J.-P., Murith, C., Palacios (Gruson), M., Baechler, S., 2015Improved predictive mapping of indoor radon concentrations using ensemble regression trees based

on automatic clustering of geological units.

Journal of Environmental Radioactivity 147, 51 - 62



May 25, 2016




11

More criteria to construct the radon map

• radon measurements

• lithology (geology)

• clustering of geological units

• meteorological data

• machine learning

• modeling

• multidimensional analysis



May 25, 2016




12

Radon measurements ~230 000 measurements

~145 000 houses



May 25, 2016




13

Lithology – 70 classes



May 25, 2016




14

Generalized lithological classes

Mean

of

indoor

radon c

oncentr

ation i

n B

q/m

3

100

150

200

250

300

350

400

Carbonate

Rock Alps

Carbonate

Rock Jura

Igneous Rock Metamorphic Rock Sediment Sedimentary Rock

Rock class



May 25, 2016




15

Creating artificial classes



May 25, 2016




16

Modeling

prediction

radon

concentrations

categorical

variablescontinuous

variables

model

housetype altitude



May 25, 2016




17

Probability mapping



May 25, 2016




18

Radon probability map

Future improvements: more

variables:

• uranium content of the

ground

• soil gas measurements

• more detailed geological

information

• outdoor/indoor pressure

differences



May 25, 2016




19

Thank you for your attention!

I am happy to answer

questions.

radon map of switzerland - nucleus documents/radiation... · federal office of public health foph...

Documents