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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

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

2

Current Radon Map

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

3

Radon measurements 1994-2015 (in living spaces)

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

4

Radon Map 2004

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

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

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

6

Consequences of the community based classification

Canton Neuchâtel

Canton Basel-Land

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

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

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

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

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

9

2% 12%

New map, the entire country is a radon prone area

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

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

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

11

More criteria to construct the radon map

• radon measurements

• lithology (geology)

• clustering of geological units

• meteorological data

• machine learning

• modeling

• multidimensional analysis

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

12

Radon measurements ~230 000 measurements

~145 000 houses

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

13

Lithology – 70 classes

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

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

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

15

Creating artificial classes

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

16

Modeling

prediction

radon

concentrations

categorical

variablescontinuous

variables

model

housetype altitude

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

17

Probability mapping

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

18

Radon probability map

Future improvements: more

variables:

• uranium content of the

ground

• soil gas measurements

• more detailed geological

information

• outdoor/indoor pressure

differences

Regional Workshop on Radon in Workplaces

Fabio Barazza, Switzerland

May 25, 2016

Federal Department of Home Affairs FDHA

Federal Office of Public Health FOPH

Consumer Protection Directorate

19

Thank you for your attention!

I am happy to answer

questions.