Radon in Slovenian Homes: A Hidden Health Risk and What to Do About It
Radon is one of the most underestimated health hazards in residential buildings. This naturally occurring radioactive gas is colorless, odorless, and tasteless, yet long-term exposure significantly increases the risk of lung cancer. According to the International Agency for Research on Cancer (IARC), radon is the second leading cause of lung cancer after smoking.
In Slovenia, this problem is particularly acute due to the country’s geological features.
What is radon and how does it enter buildings?
Radon is formed by the decay of uranium in the earth’s crust. From the soil, it penetrates buildings through microcracks in the foundation, construction joints, utility penetrations, drainage channels, and shafts.
Radon dissipates quickly outdoors, but it accumulates indoors, especially on the ground floors and in basements.
Why is radon dangerous?
The gas itself is quickly exhaled by humans, but its decay products settle in the respiratory tract. As they decay further, they emit alpha particles, which damage lung cells.
According to statistics, up to 10% of lung cancer cases in the country are directly related to household radon. In Slovenia, more than 100 people die annually from the effects of radon exposure. The risk increases exponentially for smokers.
Where is radon highest in Slovenia?
Radon levels are influenced by the geology of the site (soil porosity, karst rocks in the region, the presence of tectonic faults in the surrounding area), the type and age of the building itself, and the quality of waterproofing and ventilation.
The highest concentrations are found in regions with karst and gravelly soils. Areas with increased radon risk include, in particular, the following municipalities: Postojna, Logatec, Idrija, Cerknica, Kočevje, Sežana, Divača, Vrhnika, Ribnica, Pivka, Ig, Ivančna Gorica, Žužemberk, and others.
The state has also designated additional monitoring zones where regular, expanded measurements are conducted.
Permissible Radon Levels
Slovenia has a radon reference value of 300 Bq/m³. This is the level below which mandatory mitigation measures are generally not required.
If radon levels are significant and long-term, the property owner is required to take measures to reduce the gas concentration.
How to Measure Radon in a House or Apartment
Measurements are conducted by accredited laboratories and through government programs, as well as by self-measurement using household detectors.
The Slovenian Radiation Protection Authority offers the opportunity to temporarily rent simple measuring instruments for initial assessments.
Important: Official decisions on mandatory measures are made only based on certified measurements.
How to Reduce Radon Concentrations
Methods depend on the building’s design and the level of excess. In practice, the following are used:
1. Improved ventilation. This is the simplest and most effective step: regular ventilation, installation of supply and exhaust systems, and basement ventilation.
2. Sealing structures. Seal cracks and joints, seal utility inlets, and improve foundation waterproofing.
3. Engineering solutions. For high concentrations, ventilation of the soil under the floor slab, special radon drainage systems, and foundation reinforcement are used.
Radon and New Buildings
Modern building codes in Slovenia require that new residential and commercial buildings be designed with radon protection in mind.
Technical standard TSG-1-007:2023 — Zaščita pred radonom v stavbah (Technical Directive on the Protection of Buildings from Radon) defines:
– mandatory design solutions,
– foundation requirements,
– methods for preventing gas penetration.
If a building is constructed according to these standards, it is considered radon-proof.
Why is this important for real estate buyers?
For buyers, radon is a health issue, a factor in the long-term marketability of the property, and potential future remediation costs.
When purchasing a house or apartment, especially in high-risk areas, we recommend verifying radon level measurements at the location, paying attention to the type of foundation and ventilation, and taking into account the year of construction and the applicable building standards.
Conclusion
Radon is not a theoretical threat, but a real risk factor for thousands of homes in Slovenia. The good news is that the problem can be controlled: it can be measured, its concentration reduced, and taken into account when purchasing a property.
At ALTUM CAPITAL, we recommend our clients take radon safety seriously. This is an investment in health, living comfort, and the long-term value of their property.
This material was prepared specifically for posting on the ALTUM CAPITAL real estate agency website.
Sources: https://www.gov.si/teme/zmanjsevanje-izpostavljenosti-radonu/https://www.zvd.si/sevanje-in-dozimetrija/radon/?fbclid=IwY2xjawPpY19leHRuA2FlbQIxMABicmlkETFSYnAxTVJ5Wk5HR0lDT0Vvc3J0YwZhcHBfaWQQMjIyMDM5MTc4ODIwMDg5MgABHqJHv7omTXKrJdm9bFlmk2KH23Vhq_vONQPxXhJskuPJcr4vQ8SUECZQSDN3_aem_WLEobVLQAKGQvTSqFWV9iA
