Concerning radioactivity, the attention of the public is mainly focused on artificial radiation sources (especially on nuclear installations, radioactive waste, etc.). Nevertheless, people do not know that the highest exposure of the population is caused by natural radioactivity, and especially by indoor radon, which causes the most significant exposure in buildings. Radon and its daughters in the indoor air of houses, schools, and workplaces cause more than 70 percent of the total radiation doses of the population. The Czech Republic, with its average volume radon concentration of 140 Bq/m3 (this corresponds to the equilibrium-equivalent radon concentration of about 60 Bq/m3) , belongs to the countries with the highest average radon concentration in the world. Nevertheless, the radon occurrence in houses is not uniform - some persons are exposed to doses that are higher by one to two orders compared to the mean value, and in some exceptional cases the doses may achieve the limit for deterministic radiation effects; for example, the highest radon concentration in dwellings that has been found in our country corresponds to the annual dose of about 500 mSv.
The reason for the abnormally high values of the radon concentrations in our houses is the higher uranium and radium occurrence in the soil in our country, bad gas insulation of the houses from the ground, and finally, lower ventilation for energy savings. The exposure to radon (more precisely exposure to its radioactive daughters) may cause lung cancer, as discussed in many epidemiological studies of uranium miners and some cohort studies. The impact of the above-mentioned radiation on public health has been estimated at 900 deaths per year in the Czech Republic due to lung cancer (this is about 15 percent of all lung cancer deaths). This excessive irradiation of the population, which is unnecessary, and which was caused by our unfamiliarity with the radon problem in the past, has not been eliminated so far. All the buildings with a high radon risk so far have not been found and reconstructed (the expected number of radon affected houses ranges from 60,000 to 70,000, and of these houses only 14,000 houses have been found, and 2,000 houses have been reconstructed so far). The population has not yet devoted attention to radon risk (compared to nuclear power engineering), and very often people are not willing to make the simplest in newly built houses.
What is RADON PROGRAMME?
With respect to the possible health impact from exposure to radon, the governments (both in our country and abroad) try to regulate exposure to radon. The Czech government approved the RADON PROGRAMME by its Resolution no. 538, dated May 31st, 1999. This programme is concentrated on the preventive remedial measures , that should not only reduce exposure to radon in new buildings but in the existing dwellings (by interventions).The Radon Programme also involves a target survey of dwellings with higher radon concentrations, better public awareness, and development and research.
1. The preventive remedial measures should involve the following:
- The legislation for regulation and control of all possible radon sources (for instance, radon from soil, building materials and water). The legislation has been established: there is the Atomic Law and the other regulations.
- Quality control system (i.e., all producers and importers of building materials and the water suppliers are controlled by SÚJB inspectors, and the assessment of radon in soil is an integral part of building permission. The planning authorities are responsible for their approvals).
- Sufficient awareness of the public.
2. Interventions to reduce exposure to radon in existing buildings
There is the question whether or not the reduction of exposure to radon may be required for the owners of houses (if yes, than specify in what cases), or the owner will make his own decision to carry out the measurements and remedial measures. The alternative of the forced measurements and is usually unacceptable for democratic countries, and this conception has also been refused in our country with the exception of buildings of public interest.
The programme of interventions is based on the offer of the state support and a free decision of the people to accept this support.
In practical terms, the programme is implemented in the following steps:
- A representative survey of radon occurrence in houses in the territory of the Czech Republic (i.e., "surveying the situation").
- The intervention levels to implement the - were specified by SÚJB Regulation no.307/2002 Coll.
- Awareness of the public and all state authorities - for this purpose, the informative materials are issued.
- Organizing the target survey of buildings with higher radon concentrations, especially in the risk areas - this is carried out in cooperation with local authorities. More than 100,000 houses have been measured so far.
- Assistance to people owning the houses in which the values that exceed the intervention levels have been measured. Implementation of in the form of state financial support - the sum is annually specified in the state budget - and district authorities provide the amount for remedial measures.