Thanks anon. I was thinking about it when reading an old post that someone had put up asking jobs somewhere and what certain companies were like to work for.

I notice on the charts that spikes occur in the AM hours. Does anyone know why?

Anyone out there??

Hi Anthony,
Spikes are often associated with increased Radon gas concentration, which seeps naturally from the ground. Low pressure can pull it up from soil pores, warming by the sun can cause air currents to bring 'pools' to detectors, rain can bring it back down to the surface. Those detectors that filter the air are more sensitive to this, as Radon decay products are sticky solids easily caught.

Thank you for the reply. So these high peak readings have nothing to do with any vapor stacks releasing dangerous gas at these hours?
Thanks
Tony

If you are referring to power reactor cooling towers, they emit steam, and although the steam may contain Tritium (a radioactive form of Hydrogen), the EPA and private NETC detectors cannot really detect it due to the low energy of the beta decay particle (it is stopped by some 6 mm of air). The spikes seen on the detectors is much more likely natural Radon and related particles.

The AM Hour spikes that one finds on RadNets data are not radon induced. RA222 and almost every single of its daughters down the line produce Alpha and the occasional Beta particle. No Gamma. Its something else, and remember...Radnet no longer gives out Beta Data, only Gamma 2-9 and Dose Rate.

The Radon (222) daughter component Bismuth (214) is a gamma source, and based on its gamma energy level is shown to be the source of daily variations in this study: https://www.sciencedirect.com/science/article/abs/pii/S1364682620301802. Radon exhaled by the ground tends to be more concentrated near the ground in the early morning. After the sun rises, it is diluted by warming and air movement.

The above paper can also be read at this link: https://www.researchgate.net/publication/337241701_Causes_of_the_Diurnal_Variation_observed_in_Gamma-ray_Spectrum_using_NaI_Tl_Detector

Bi-214 is pretty short lived and only produces a strong gamma in the 609 KeV range, which is RadNets Energy Range 5 (600-800 KeV). While this IS the gamma range that NETC uses, some of the other gamma ranges ALSO follow this daily pattern...at least that is what RadNet shows. Also, not all of the sites have a Radon issue, if you look at the Radon Maps of the USA. Something doesn't make sense here.

Bi-214 emits gamma at 2 energy levels, and the study authors refer to a compton scattering effect at a third, lower level. There is another gamma emitter in a separate decay chain (Thallium-208, from Radon-220) that was found to fit the data as well. I don't know if this study was replicated in any way the USA, but it seems to explain the patterns at the EPA sites. The USA Radon maps appear to correspond to average levels on the EPA sites; red areas (high Radon potential) have higher averages than yellow areas, at least for the handful that I sampled. You have a good point that low Radon areas should show little daily variation, yet the EPA graphs show plenty of daily variation everywhere. What I don't know is how closely the Radon maps show the raw soil Radon levels. I believe they show the potential for accumulation in basements based on other factors as well (soil type, moisture, etc). It's possible that atmospheric Radon itself is more evenly distributed.