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KbarKbar t1_jcahmz4 wrote

Reply to comment by stefek132 in Radon is a monatomic gas, but its decay products are solids. After a decay, what happens to the individual atoms of the daughter elements? Do they stay suspended in the atmosphere or slowly rain out? by foodtower

To add to the already-excellent analysis already posted, I have to quibble about:

>There’d be a gradient originating from the source...

Exactly what "source" are you envisioning here? We're talking about radon gas mixed freely in the atmosphere. Any decay products would be distributed randomly and diffusely, as there is no monolithic source from which to originate.

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Bbrhuft t1_jcffirz wrote

He was correct. Lead oxide isn't formed.

There's several factors that need to be considered. The fact that the Lead-214 daughter is singly ionized so reactions with oxygen aren't favoured, that air is humid and is often contaminated with VOCs and SO2, especially indoor air, and the fact that these reactions take place within an ionization trail generated by the Alpha particle, that generates hydroxy radicals from atmospheric humidity and NO2 (the radon daughter atoms recoil at 10-13 million mph btw).

Instead, Lead-214 will most often form tiny clusters surrounded by 5 to 8 water molecules and likely often a few molecules of VOCs. They measured the size of the clusters, they average 1.2 - 2 nm in diameter. Po-218 is a little different, it forms larger 15 nm clusters additionally with SO2 (once air contains a few ppm of SO2) and as, well as much smaller clusters of PoOx 0.5 - 1 nm in diameter (the proportion of these clusters depends on what's in the air).

Castleman Jr, A.W., 1991. Consideration of the chemistry of radon progeny. Environmental science & technology, 25(4), pp.730-735.

Hopke, P., 1996. The initial atmospheric behavior of radon decay products. Journal of Radioanalytical and Nuclear Chemistry, 203(2), pp.353-375.

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Lazz45 t1_jcfim9y wrote

I would take source to be the largest point of entry, and point from where the radon gas diffuses out into say the basement. However, I see your point in that it's not like a heat source or lead atom generator that constantly acts like a "lead source"

From what I can see, the gas gets in via cracks/voids in the foundation so in theory you could take those points of entry as "sources"

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