Radon gas in homes - Radoff
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Discover what Radon gas is, how it is distributed, what it causes, how to measure it and how to defend itself

Radon gas in homes

Radon is a pollutant present everywhere because its ancestor, uranium, is an element widely present in nature, however it becomes of particular interest from a health point of view only when it is present in confined environments: the so-called indoor radon.

In fact, if the radon gas, produced by the soil and rocks, escapes and is diluted in the atmosphere, its concentration is so low that it does not constitute a risk to health; if, on the other hand, the radon gas enters a confined environment, it will tend to accumulate and reach levels that represent a risk.radon1 770x770

Radon is a pollutant present everywhere because its ancestor, uranium, is an element widely present in nature, however it becomes of particular interest from a health point of view only when it is present in confined environments: the so-called indoor radon.

In fact, if the radon gas, produced by the soil and rocks, escapes and is diluted in the atmosphere, its concentration is so low that it does not constitute a risk to health; if, on the other hand, the radon gas enters a confined environment, it will tend to accumulate and reach levels that represent a risk.

Radon is a radioactive decay product of the uranium chain, it is a noble gas produced by the "radioactive disintegration" of the radius contained in the rocks. It is observed in fact that in nature there are some atoms called unstable due to their property of transforming themselves without external influences into other atoms, thus changing their identity and becoming other chemical elements. This transformation is called in the scientific language "radioactive disintegration" or simply "radioactivity". The atoms that are formed are called "radioactive elements".

In the particular case, the natural disintegration of uranium gives rise, via a series of intermediate products, to radium and subsequently to radon. Unlike its precursors in the radioactive chain, which remain in the earth's crust, radon gas has the ability to move between the pores of solid materials, to be transported to the surface and to reach the atmosphere.

Radon atoms can further disintegrate forming, by decay, atoms children of polonium, lead and bismuth. The radon children, as these decay products are also called, are radioactive atoms present in the air, which thanks to their property of being positively charged and chemically active react very quickly both with vapors-gases present in the atmosphere becoming small particles and sticking easily to aerosol particles already present in the atmosphere.

Therefore it is observed that the major fraction of exposure to natural radiation is due to the inhalation of radon gas and its decay products, which are present in the atmosphere and, in higher concentrations in the air of enclosed spaces (dwellings, places of work, etc.)

The main sources of radon pollution in confined spaces are:

  • the soil,
  • building materials,
  • the water.

The radon produced in the soil is able to spread up to the surface. A gravelly or cracked soil will allow the gas to move easily through the rocky layers, while the clay-rich layers of water will show a certain resistance to its passage.

Building materials usually represent a source of indoor radon of secondary importance with respect to the ground; however in some cases they may be the main cause. Some rocks such as granite and porphyry, often used in construction and some typical Italian building materials, such as tuff and pozzolana, contain a high uranium content, the progenitor of radon.

The main source of radon in homes is the foundation of the building. The gas propagates from the inside of the earth through the rock and the ground to the surface. The amount of radon that is formed in rocks and soil depends strictly on their uranium and radium content. From a geological point of view, the distribution of these two elements in the soil varies according to the type of rock or soil according to the place and the training methods. The radio content and the type of rock deposit influence the radon concentration in the building land.

The processes that determine the migration of radon in the soil are essentially three:

  1. the diffusion,
  2. the convection,
  3. transport by a fluid.

Diffusion and convection allow the radon to move over distances in the order of centimeters or meters, while the transport by a fluid can lead to migrations for greater distances. Fluid mobility in the subsoil and therefore the radon migration capacity is influenced by soil permeability, the amount of water present and other geological parameters such as karst, soil fractures and the presence of clay layers.