So , the health effect of radon is not because radon is trapped in the lungs as stated in the solicitation , but rather , the decay products of radon that are inhaled . If radon , as well as other gasses were held up in the lung , we would quickly expire from accumulated carbon dioxide .
One can see this mechanism explained in many authoritative works on the health effects of radon , such as :
Biological Effects of Ionizing Radiation ( BEIR VI )
“ Alpha particles released by 2 radioisotopes in the radon decay chain , polonium-218 and polonium-214 , deliver to target cells in the respiratory epithelium the energy that is considered to cause radon-associated lung cancer ” [ 2 ]
Technical Support Document for the 1992 Citizen ’ s Guide to Radon :
“ Of the short-lived radon decay products ( polonium-218 . Lead-214 , bismuth 214 and polonium-214 ), the polonium isotopes contribute most of the radiological dose to the lung . The risk from inhaled radon-222 is small compared to the risk from inhaled radon 222 decay products ” [ 3 ]
Exposure vs Dose
It comes down to the difference between being exposed to a hazard , versus receiving a bodyharming dose . Radon in indoor air represents an exposure much like the sun represents an exposure for potential skin melanoma , but the actual risk is what is absorbed by the body — or if you are indoors or outdoors , or you wear a hat or long-sleeved shirts .
In the case of elevated indoor radon , there are a known amount of radon decay products that will be formed in the air around us . However , that does not mean that is what will enter the lungs as we breathe . A large portion of the radon decay products ( 50 to 60 %) will attach to physical objects within a room and no longer be breathable . This is reduced further with the use of particulate air filters and air circulation as occurs in schools and large buildings . What remains after these reductions is the actual dose that can be imparted to the lungs .
So why do we routinely measure radon rather than radon decay products ?
Actually , many of the miner studies linking radon induced lung cancer are based upon direct radon decay product measurements . Even more recent epidemiological studies of lung cancer incidence in residential settings show a much better correlation to radon decay product measurements than radon alone . That is because they are a better measure of dose received rather than an inferred dose from exposure .
Radon measurements are indeed easier to make . They are simple and affordable . But realize a radon measurement is a surrogate or substitute measurement for estimating health risks of the radon decay products . In many situations , quantifying the radon potential is adequate and reducing radon entry via active soil depressurization reduces radon and , inturn , reduces the attendant radon decay products proportionately .
However , there are cases where an additional quantification of radon decay products is prudent . This certainly would be the case in larger buildings where efforts by EPA to reduce indoor particulates via better HVAC systems and filters can have a significant impact on