RADON IS ONE OF THE LEADING
CAUSES OF LUNG CANCER
WHAT IS RADON GAS?
It is a colourless, odourless and tasteless radioactive gas produced by the decay of uranium. It is present in almost all soils, and very low levels of radon are found in the air we breathe every day. While radon is everywhere, the important question is: what is the concentration in your home? Further decay generates radioactive decay products that enter the lungs through the air we breathe and emit alpha radiation, among other things.
WHY IS THIS AN ISSUE?
Radon is an inert gas that does not react with other elements, and it escapes into the air through cracks and holes in the ground. The problem arises when radon gas enters a home and becomes trapped inside. Prolonged exposure to high levels of radon can cause lung cancer. According to recent research, between five and ten per cent of lung cancer cases in the European population are attributed to exposure to radon and its decay products in buildings.
HOW DOES IT GET INTO A HOME?
The gas moves from the ground into the home. Although it can seep directly through concrete, cracks in walls and floors are the most common entry points.
Any home, regardless of its age or location, can have high levels of radon. This depends on how your home interacts with the surrounding soil. The radon level in your neighbour's home may be very different from yours.
SPECIALISED TRAINING
Our radon mitigation training and certification were completed through CERTI, an elite program approved by the National Radon Proficiency Program (NRPP) and the National Radon Safety Board (NRSB). The NRPP is administered by the American Association of Radon Scientists and Technologists (AARST) and is the only radon certification program to earn ANSI (American Standards Association) accreditation, ensuring our work strictly adheres to the highest national safety standards.
RADON GAS MEASUREMENT
CONCERNED ABOUT RADON GAS
IN YOUR PROPERTY?
It is essential to know whether your building is affected. We can help you obtain an accurate diagnosis, and if the radon levels are high, we can work with you to design the most efficient technical solution to protect your health and that of your loved ones.
WHO handbook on indoor radon
After tobacco, radon is the second leading cause of lung cancer in the general population. Epidemiological studies have convincingly demonstrated a link between exposure to indoor radon and lung cancer, even at the relatively low levels typically found in residential buildings.
HEALTH AND SAFETY: RADON GAS THRESHOLDS
Current regulations in Spain (CTE DB-HS 6) set a reference level of 300 becquerels per cubic metre (Bq/m³), but the World Health Organization (WHO) advises keeping exposure below 100 Bq/m³ to minimise chronic risks.
Current regulations (Royal Decree 1029/2022, which transposes Directive 2013/59/Euratom) require administrations and companies to measure and control radon levels in workplaces, setting 300 Bq/m³ as the reference value for the annual average.
In our biohabitability audits, we work under the precautionary principle, prioritising excellence in biological health by establishing safety levels that far exceed legal requirements.
BAUBIOLOGIE INSTITUTE
OMS
KEY TIPS
EUROPEAN STANDARS
1ST STEP
Detection and measurement:
As radon cannot be smelled or seen, the only way to know if it is present is to measure it.
A. Instant digital measurement.
B. If gas is present, a kit is sent for evaluation by an approved laboratory.
Please note that, in order to be approved, an assessment must be carried out by an ENAC-accredited laboratory (ISO 17025) and have a minimum duration of three months.
2ND STEP
Strategic ventilation:
A· Cross ventilation: Opening windows on opposite sides of the house quickly reduces concentrations.
B. Mornings and evenings: Radon tends to accumulate overnight. It is critical to ventilate thoroughly first thing in the morning.
3RD STEP
Action on the structure (physical barriers):
A. Sealing cracks: Check and seal cracks in the floor slab, expansion joints, and pipe penetrations using elastic materials.
B. Radon membranes: In renovations or basements, specific high-density polyethylene sheets are installed.
C. Suction chambers: In severe cases, a small extractor fan is installed to draw air out from under the house.
At BioWellness, we combine science and experience to guarantee healthy environments, backed by accredited laboratories. Our state-of-the-art radon gas detection instrumentation enables us to apply rigorous technical protocols that minimise implementation costs without compromising safety or the quality of the final result.
RADON GAS MAP
In Spain, radon gas poses a greater risk in areas with granitic and metamorphic soils, particularly in the north-west (Galicia), centre (Castile and León, Madrid) and on the coast. In Andalusia, 30% of the soil is at potential risk, particularly in Almería, Córdoba and the Sierra Norte de Sevilla, as well as in pockets concentrated in Málaga province, due to the presence of igneous rocks.
IMPACT ON HEALTH
According to recent estimates, radon gas causes approximately 838 to 1,200 lung cancer deaths per year in Spain. This naturally occurring radioactive gas is considered the ‘invisible killer’ and is responsible for around 3.8% to 4% of lung cancer deaths in Spain, a figure which rises to 7% in high-risk areas such as Galicia and Extremadura.
MEASUREMENTS
The only way to determine the actual radon levels in a building is through measurements. Often, a few simple measures are enough to significantly reduce radon levels and therefore the risk of lung cancer.
Image courtesy of the Eduardo Torroja Institute of Construction Science (IETcc).
A CITIZEN'S GUIDE TO RADON
The Guide to Protecting Yourself and Your Family from Radon
Guidance document.
Based on the 2025 update of the United States Environmental Protection Agency (EPA), this document analyses the global scope of radon gas. While US and European regulations differ in their technical application, US regulations converge with the World Health Organization (WHO) guideline. The WHO recommends keeping exposure below 100 Bq/m³ to minimise associated risks in residential and occupational settings.
*The standard measurement in the US, 1 picocurie (pCi/L), corresponds to 37 Bq/m³ in Europe.
Precautionary level (2.0–4.0 pCi/L): Although this is below the official action level (4.0 pCi/L = 148 Bq/m³), the EPA advises homeowners to consider mitigation and remediation if their radon levels fall within this range. This is because reducing radon levels always lowers the risk of lung cancer.
Video published by the American Lung Association.
FREQUENTLY ASKED QUESTIONS
What is radon gas?
Radon (²²²Rn) is a naturally occurring, colourless, odourless and tasteless radioactive gas, which makes it undetectable to the human senses.
Origin and radioactive nature
Radioactivity is the process by which an unstable atomic nucleus emits energy in the form of particles or radiation as it decays. Radon is constantly generated by the natural decay of uranium, which is present in the Earth's crust, in rocks (especially granite and volcanic rocks), and in water.
Due to its gaseous nature, radon moves from the subsoil to the surface, either diluting in the outside atmosphere or accumulating in enclosed spaces.
The paradox of modern construction
Although radon has always been part of our environment, its presence inside buildings has only become a public health challenge in recent decades. This is due to two main factors:
1· Energy efficiency: Modern buildings are designed to maximise efficiency and save energy. While this reduces consumption, inadequate air renewal can cause gas to become 'trapped', resulting in dangerous concentrations that were not present in older, more permeable homes.
2· Due to its density, it accumulates in the lower areas of buildings, making basements, ground floors and poorly ventilated spaces critical exposure points.
At BioWellness, we understand that energy efficiency and geo-environmental health must coexist. Our analysis enables us to identify these accumulation points, restoring the purity and balance of the air you breathe.
How reliable are our radon analyses?
To ensure the safety of our customers, we only work with laboratories that strictly adhere to the Nuclear Safety Council's (CSN) protocols. Our associated analysis centre is accredited to ISO/IEC 17025, the global quality standard for testing laboratories. This requirement, as set out in guideline GS-11.01, ensures that our results are accurate, traceable and officially recognised by health and building authorities.
How does radon enter buildings?
Radon gas has a high diffusion capacity. Since it is present in the air beneath the ground, it migrates towards the surface in search of areas of lower pressure. Since the interior of homes usually has slightly lower pressure than the ground (due to the chimney effect and air conditioning), buildings act as natural gas extractors.
Radon does not require large openings; its atomic nature enables it to penetrate micro-cracks and structural discontinuities.
- Structural discontinuities: Cracks in concrete floors and fissures in load-bearing walls or enclosures.
- Joints: Construction joints and joints between the floor and the wall (cold joints).
- Chimney effect in chambers: Spaces in sanitary slabs or suspended floors, as well as internal cavities in hollow brick walls.
- Technical wall penetrations: Gaps and spaces around plumbing, sanitation and electrical connections.
- Water supply: Emanations from untreated well water (gas released when using showers or taps).
Origin and source:
Although certain stone-based building materials can emit radon, the technical evidence in the geological context of Spain is clear: 80% of radon emissions come directly from the subsoil, while the remaining 20% is attributed to the materials used in construction.
At what level is radon considered a health risk?
Radon concentration in the air is measured in becquerels per cubic metre (Bq/m³). While the average indoor level in Spain is between 40 and 50 Bq/m³, it is important to recognise when these levels require technical intervention.
Reference and action levels
According to the Nuclear Safety Council (CSN) and the World Health Organisation (WHO) guidelines, there are two key decision-making thresholds:
- Existing homes: The action level is set at 300 Bq/m³. Exceeding this figure requires corrective measures to be implemented as a matter of priority.
- New buildings: The design target for new homes is stricter at 100 Bq/m³.
The concept of biological safety
It is important to understand that 300 Bq/m³ does not represent a clear distinction between 'safe' and 'dangerous' air, but rather a technical action level. From a biohabitability perspective, there is no zero risk threshold; therefore, the lower the radon concentration in your home, the greater the protection for your health and that of your family.
Health impact and prevention
There is solid scientific evidence that the risk of developing lung cancer increases by around 16% for every 100 Bq/m³ increase in long-term exposure.
Children under the age of 10 are particularly vulnerable.
The good news is that current mitigation technologies effectively reduce radon levels in the vast majority of properties to 50 Bq/m³, the level recommended by green building standards. At BioWellness, our goal is to not only comply with this standard, but also to transform your home into an environment that promotes optimal health.
How can I monitor radon gas levels in my home after they have been reduced?
1. Continuous digital monitoring:
Ionising pulse chamber sensor technology allows you to see the evolution of the gas in real time.
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Advantage: You can set alerts on your mobile phone if levels exceed 100 Bq/m³.
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Data analysis: These devices display daily, weekly and monthly graphs. This is vital because a single measurement may be low, but the weekly average may reveal dangerous peaks during the night.
2. Annual contrast tests (passive detectors)
Even if you have a digital monitor, it is good biohabitability practice to take a 'long-term' measurement (three months) every year, preferably in winter.
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Reason: digital monitors can become miscalibrated over time. Sending a nuclear tracer detector to a laboratory for analysis provides an external audit to confirm that the mitigation system (sheets or extractors) is still working as effectively as on the first day.