Would you be surprised to find out that NC State is, and always has been, a source of uncontrolled radioactive aerosol and gas releases into the environment? Would you be surprised to know that you are actually breathing it in right now? Would you be surprised to find out that this kind of radioactive air exposure contributes more than 200 mrem radiation dose to the average American per year, twice of that allowable for a non-radiation worker at a nuclear facility?  Would you be surprised to find out that this is preventable for those willing to pay the price to avoid it?

It turns out that this is due to the nature of our environment in that the crust of the Earth is a few parts per million uranium with even more thorium, both of which are radioactive elements and are as natural as water, soil and air. These elements decay into more radioactive elements, and so on, eventually becoming radium. Radium itself decays into radon which is both a noble gas and radioactive. Radon decays further into a series of heavy metals (which are also radioactive) that we all breathe every day and have done so from the beginning.  

In fact, because radioactive decay results in less radioactivity over time, the further back you go, the more radioactive things become (including us). The scientific literature is pretty clear that life is designed to operate in radiation fields similar to those found in the biosphere today (actually a bit higher).  

Science also tells us that another primordial radioactive element is in fact essential to life on Earth: potassium. Carbon is also slightly radioactive, and because it also is essential to life, it allows scientists to carry out carbon dating in organic material for archeological applications.

Last but not least, exposure to radon progeny is, in a strict sense, entirely preventable (as mentioned above) but you would have to walk around wearing something like a gas mask continually as well as sleep in one.  That said, it is probably safe to say we are designed to handle this well enough without protection, given that things on Earth have always been this way.

Robert Hayes is an associate professor of nuclear engineering.