First, I am probably as much as a layman as you. But from what I have read and some quick googling now, there is no additional risk or appreciative difference. Although I did find a few regulations that the general public should not be exposed to any sort of radiation higher than 10 µSv per hour. However I believe that is to prevent regular people unknowingly being around high radiation sources that would add up to a high cumulative total, since the general public does not have any way to track their cumulative exposure, not a problem with that level of single dose radiation per se.

Ionizing radiation damage is overwhelmingly and almost exclusively in its cumulative effects, namely the cancer it can cause. Each “unit” of radiation has a certain likelihood of slicing through the DNA of one of your cells, which has a certain likelihood of causing a mutation, which has a certain likelihood of being a cancerous mutation and not a “kills the cell” mutation, which has a certain likelihood of being a specific type that can evade all the body’s natural defenses against rouge cells. It is a long chain of dice rolls that have to all go just wrong.

So, unless the dose is concentrated to a physical location, e.g. radon in the lungs or sunburn on the skin, then it doesn’t really matter if you get a given dose over a month or a year. It will still start the same number of cascading dice rolls.

If someone that actually knows what they are talking about feels the need to correct anything, please do.