CR3 News Magazine 2022 VOL 5: NOVEMBER -- RADON and CLIMATE CHANGE | Page 8

Where Does My Radon Go When it's Done Being Radon?

and better things to worry about

Peter C. Foller, Ph.D.

Advisor to Ecosense

Have you heard the story of how the presence of dangerous levels

of radon in homes first received mainstream attention?

It was in 1984 when a Pennsylvania construction engineer, Stanley Watras, showed up for work at the newly built Limerick nuclear power plant (Montgomery County, Pennsylvania) and was the subject

of a trial run of the plant’s new radiation safety screening equipment. He was contaminated! But how? The plant had not yet even received its fuel rods. There was nothing radioactive on site.

As the logical next step, Mr. Watras’ home was tested. It turned out his basement measured about 2,700 pCi/L (~675 times the level of radon the EPA eventually set for its strong recommendation to mitigate a home). The home was unknowingly built atop an unusually high natural occurrence of uranium. As we all know, radon is a gas, so how did a gas follow him to work? The answer is it did not, radon’s decay products did.

Radon gas turns into other elements through radioactive decay. These are called their “progeny.” They and their air oxidation products are solid materials. For a given quantity of radon gas, every 3.8 days half of it kicks out a high-energy (meaning high-speed) alpha particle and becomes an atomic scale particle of solid material. Thus, the term “half-life.” Within 15 days (4 half-lives), only 1/16th of the original radon gas is still present. The trouble is radon continuously enters our homes, so it establishes a steady-state level (which rises and falls in accordance with the daily variation of indoor/outdoor temperature/pressure differential and openings and closings of doors and windows, etc.).

Radon’s atomic-scale decay products can stay suspended in air, but eventually tend to attach themselves to airborne dust and/or directly settle onto surfaces of all kinds: dining room tables, countertops, carpets, clothes, etc. The latter, his clothes, probably set off Mr. Watras’ screening alarm. These atomic-scale solid products of radon decay are themselves radioactive. With alpha and beta particle emissions of various energies at every step, within a couple of hours most all radon decays into the element polonium, then to either astatine or lead, and from there to bismuth, then on to either thallium or polonium and finally into an isotope of lead bearing the rather calm half-life of 22.3 years. Including that of radon itself, there are 9 possible particle-emitting decays in the above quite rapid chain of events.

So, what makes radon and its progeny so dangerous to lung tissue? It is that if decay occurs within the lungs, atomic-scale solids are likely to be retained, and thus, continue upon the above rapid series of decays-- putting out a virtual shower of high-speed alpha and beta particles. Alpha particles are helium nuclei-- veritable cannon balls of 4 atomic weight units (AMU). They are so massive they cannot penetrate far, only a few cells, but that is where they deposit their energy, damaging DNA, the code of life. Beta particles are electrons, which have far less mass (only 0.00055 AMU), but can they can penetrate a centimeter or so into tissue since they travel at significant fractions of the speed of light. Outside of the body, alpha and beta emitters are far less dangerous. Alpha particles can generally travel only a centimeter or so in air and beta particles a few meters. It is fair to say radon and its progeny are presently of proven danger only within our lungs.

So, in the air within our homes, radon decay products are continuously falling out onto surfaces and ending up on and amongst our house dust. But, can this knowledge make us any more healthy and safe? Should the most health-conscious amongst us dust their homes more diligently? Well, maybe, but I’d suggest it for a different reason unrelated to radioactivity.

Our nasal passages are so engineered that ordinary levels of house dust are unlikely to enter the delicate tissue of the lungs-- it is far more likely such material is trapped by the function of our nasal passages and then is likely to be expelled from our bodies (one way or another) as designed. However, many of us know our nasal passages do not play well with dust. And not just any old outdoor dust, but house dust specifically. Why?

It turns out that amongst all the particles from outdoor air, the fibers shed by our textiles, tissues, carpets, and whatever all else, there is translucent a little devil (0.2-0.3 mm long) we cannot typically see called the American house dust mite, dermatophagoides tarinae (depicted), who happily makes a home for itself in our house dust. It feasts dead skin cells, which we are shedding everywhere all of the time. It is his bodily proteins, eggs, and feces that set off allergic reactions in many of us. One of CR3’s allied organizations the American Lung Association listed dust mites as indoor air pollutants due to their significant role in allergies and asthma.

There is very little to be done about this mite other than to keep a clean house. If it helps keep you motivated in going about such chores, just remember what this ugly little critter looks like and that you are also cleaning up the infinitesimal (and safe enough!) remains of your radon too.

While doing so, maybe spare a thought that you, and your family, friends, and neighbors, might check up on how much breathable radon is out there floating about in our indoor air in the first place. We at Ecosense are here to help to detect your radon levels. And we make it simple.

As the logical next step, Mr. Watras’ home was tested. It turned out his basement measured about 2,700 pCi/L (~675 times the level of radon the EPA eventually set for its strong recommendation to mitigate a home). The home was unknowingly built atop an unusually high natural occurrence of uranium. As we all know, radon is a gas, so how did a gas follow him to work? The answer is it did not, radon’s decay products did.

Continued on pg 9 ...

Radon gas turns into other elements through radioactive decay. These are called their “progeny.” They and their air oxidation products are solid materials. For a given quantity of radon gas, every 3.8 days half of it kicks out a high-energy (meaning high-speed) alpha particle and becomes an atomic scale particle of solid material. Thus, the term “half-life.” Within 15 days (4 half-lives), only 1/16th of the original radon gas is still present. The trouble is radon continuously enters our homes, so it establishes a steady-state level (which rises and falls in accordance with the daily variation of indoor/outdoor temperature/pressure differential and openings and closings of doors and windows, etc.).

Radon’s atomic-scale decay products can stay suspended in air, but eventually tend to attach themselves to airborne dust and/or directly settle onto surfaces of all kinds: dining room tables, countertops, carpets, clothes, etc. The latter, his clothes, probably set off Mr. Watras’ screening alarm. These atomic-scale solid products of radon decay are themselves radioactive. With alpha and beta particle emissions of various energies at every step, within a couple of hours most all radon decays into the element polonium, then to either astatine or lead, and from there to bismuth, then on to either thallium or polonium and finally into an isotope of lead bearing the rather calm half-life of 22.3 years. Including that of radon itself, there are 9 possible particle-emitting decays in the above quite rapid chain of events.

So, what makes radon and its progeny so dangerous to lung tissue? It is that if decay occurs within the lungs, atomic-scale solids are likely to be retained, and thus, continue upon the above rapid series of decays-- putting out a virtual shower of high-speed alpha and beta particles. Alpha particles are helium nuclei-- veritable cannon balls of 4 atomic weight units (AMU). They are so massive they cannot penetrate far, only a few cells, but that is where they deposit their energy, damaging DNA, the code of life. Beta particles are electrons, which have far less mass (only 0.00055 AMU), but can they can penetrate a centimeter or so into tissue since they travel at significant fractions of the speed of light. Outside of the body, alpha and beta emitters are far less dangerous. Alpha particles can generally travel only a centimeter or so in air and beta particles a few meters. It is fair to say radon and its progeny are presently of proven danger only within our lungs.

So, in the air within our homes, radon decay products are continuously falling out onto surfaces and ending up on and amongst our house dust. But, can this knowledge make us any more healthy and safe? Should the most health-conscious amongst us dust their homes more diligently? Well, maybe, but I’d suggest it for a different reason unrelated to radioactivity.

Our nasal passages are so engineered that ordinary levels of house dust are unlikely to enter the delicate tissue of the lungs-- it is far more likely such material is trapped by the function of our nasal passages and then is likely to be expelled from our bodies (one way or another) as designed. However, many of us know our nasal passages do not play well with dust. And not just any old outdoor dust, but house dust specifically. Why?

It turns out that amongst all the particles from outdoor air, the fibers shed by our textiles, tissues, carpets, and whatever all else, there is translucent a little devil (0.2-0.3 mm long) we cannot typically see called the American house dust mite, dermatophagoides tarinae (depicted), who happily makes a home for itself in our house dust. It feasts dead skin cells, which we are shedding everywhere all of the time. It is his bodily proteins, eggs, and feces that set off allergic reactions in many of us. One of CR3’s allied organizations the American Lung Association listed dust mites as indoor air pollutants due to their significant role in allergies and asthma.

There is very little to be done about this mite other than to keep a clean house. If it helps keep you motivated in going about such chores, just remember what this ugly little critter looks like and that you are also cleaning up the infinitesimal (and safe enough!) remains of your radon too.

While doing so, maybe spare a thought that you, and your family, friends, and neighbors, might check up on how much breathable radon is out there floating about in our indoor air in the first place. We at Ecosense are here to help to detect your radon levels. And we make it simple.

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