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The lively debate surrounding our article (1) confirms our assessment of the situation—namely, that the problem of radon in indoor spaces will have to be given closer consideration in the current debate on environmental policy in Germany.

Our article aimed to present the problems of radon pollution in indoor spaces from the perspective of environmental medicine. Radioactive pollution from power stations, radioactive contamination of tobacco leaves, or radioactivity in Iran were not subjects dealt with in our article; they would have exceeded the scope.

In the same way as any medical therapeutic measure, the use of radon in the context of radon balneology requires a careful assessment of risk versus benefits on the basis of strictly scientific criteria. However, this would require separate scientific article.

In response to Dr Schlarb, we wish to point out that the unit curie has been replaced by Becquerel (Bq), with 1 curie corresponding to 37 gigabecquerel. Radon activity concentrations in “curative” waters are usually 1.5–181 MBq/m3 of water. The release of radon from thermal spa water may result in activity concentrations in the immediate surrounding environmental air of up to 100 000 Bq/m3; such concentrations have been measured in radon healing galleries used for radon inhalation therapy (2).

We did mention potential radon content of drinking water and natural gas. The estimated mean values for radon concentrations in water in the west German states is about 400–4000 Bq/m3 (2). If drinking water contains high enough concentrations of radon then relevant exposures may be possible while taking a shower. However, the usual length of stay in a narrow shower cubicle is so limited that the contribution to the overall exposure would be limited too.

The lacking air exchange and ventilation in modern residential buildings has an important role in environmental medicine. Many pollutants (not only radon) may concentrate in indoor spaces as a result. The environmental medical demand is therefore obviously to ensure a satisfactory rate of ventilation, if required by means of technical air conditioning.

With regard to the letter by Dr Eising, we’d like to maintain that the cited epidemiological assessments were conducted in full consideration of smoking behaviors. A large number of highly potent chemical carcinogenic substances are found in the mainstream smoke and sidestream smoke (3). The radiation pollution due to radioactive isotopes—for example, polonium-210—in tobacco leaves and thus tobacco smoke will thus also contribute to the carcinogenic effect (4, 5).

After careful checking of the scientific literature we conclude that radon in indoor spaces is undoubtedly an independent risk factor for lung cancers. We are happy to support Dr Eising’s demand for smoking cessation programs, since active cigarette smoking is definitely the most important risk factor for the development of lung cancer. However, doing one thing should never mean omitting to do another. We emphatically thank Dr Shannoun for mentioning the current handbook on radon in indoor spaces and the World Health Organization’s international radon project. We agree with him that interventions are needed with regard to radon in indoor spaces.

DOI: 10.3238/arztebl.2010.0732

PD Dr. med. Klaus Schmid

Prof. Dr. med. Hans Drexler

Institut für Arbeits-, Sozial- und Umweltmedizin

der Universität Erlangen-Nürnberg

Schillerstr. 25

91054 Erlangen, Germany

klaus.schmid@rzmail.uni-erlangen.de

Prof. Dr. med. Torsten Kuwert

Nuklearmedizinische Klinik der Universität Erlangen-Nürnberg

Krankenhausstr. 12

91054 Erlangen, Germany

Conflict of interest statement
Professor Kuwert has received honoraria for speaking from Siemens Medical Solutions. Professor PD Dr Schmid and Professor Drexler declare that no conflict of interest exists according to the guidelines of the International Committee of Medical Journal Editors.

1.
Schmid K, Kuwert T, Drexler H: Radon in indoor spaces—An underestimated risk factor for lung cancer in environmental medicine
[Radon in Innenräumen: Ein in der umweltmedizinischen Diskussion unterschätzter Risikofaktor für Lungenkrebs]. Dtsch Arztebl Int 2010; 107(11): 181–6. VOLLTEXT
2.
Strahlenschutzkommission: Radon und Lungenkrebs. In: Veröffentlichungen der Strahlenschutzkommission Band 62: Einfluss der natürlichen Strahlenexposition auf die Krebsentstehung in Deutschland. Berlin: H. H. Hoffmann GmbH Fachverlag 2008; 116–66.
3.
Greim H, Deutsche Forschungsgemeinschaft: Senatskommission zur Prüfung gesundheitsschädlicher Arbeitsstoffe (ed.): Passivrauchen am Arbeitsplatz; Änderung krebserzeugender Arbeitsstoffe. Weinheim: WILEY-VCH 1999; 1–36.
4.
Winters TH, DiFrenza J: Radioactivity and lung cancer in active and passive smokers. Chest 1983; 84: 653–4. MEDLINE
5.
Muggli ME, Ebbert JO, Robertson C, Hurt RD: Waking a sleeping giant: the tobacco industry’s response to the polonium-210 issue. Am J Public Health 2008; 98: 1643–50. MEDLINE
1. Schmid K, Kuwert T, Drexler H: Radon in indoor spaces—An underestimated risk factor for lung cancer in environmental medicine
[Radon in Innenräumen: Ein in der umweltmedizinischen Diskussion unterschätzter Risikofaktor für Lungenkrebs]. Dtsch Arztebl Int 2010; 107(11): 181–6. VOLLTEXT
2.Strahlenschutzkommission: Radon und Lungenkrebs. In: Veröffentlichungen der Strahlenschutzkommission Band 62: Einfluss der natürlichen Strahlenexposition auf die Krebsentstehung in Deutschland. Berlin: H. H. Hoffmann GmbH Fachverlag 2008; 116–66.
3.Greim H, Deutsche Forschungsgemeinschaft: Senatskommission zur Prüfung gesundheitsschädlicher Arbeitsstoffe (ed.): Passivrauchen am Arbeitsplatz; Änderung krebserzeugender Arbeitsstoffe. Weinheim: WILEY-VCH 1999; 1–36.
4.Winters TH, DiFrenza J: Radioactivity and lung cancer in active and passive smokers. Chest 1983; 84: 653–4. MEDLINE
5.Muggli ME, Ebbert JO, Robertson C, Hurt RD: Waking a sleeping giant: the tobacco industry’s response to the polonium-210 issue. Am J Public Health 2008; 98: 1643–50. MEDLINE