[ RadSafe ] Adopting the International System of Units for Radiation Measurements in

[KARAM, PHILIP]

In reality, the majority of the public and most emergency responders have NO intuitive feel for ANY radiation units - it's only the radiation safety professionals who will feel the pain (or gain) from switching to SI. So if we're trying to teach someone who knows nothing about the units to begin with, there's no reason not to teach them the system that's used by the vast majority of the world. As for "academic purity" - with all respect, that statement doesn't hold water. If the vast majority of the world is using one set of units and we're not then it's not a matter of academic purity - it's a matter of keeping up with the rest of the world, which is currently ahead of us in using a consistent set of rational units. Using the logic that "we've always done well this way, why bother to change?" would take us back to cooking over open fires in front of our cozy caves. 

With regards to the thought that 37 billion Bq sounds so much worse than one Curie - I don't buy it. For example, what's wrong with saying "37 GBq" the same way we talk about 37 GB of computer storage? The way that we present things will help to color the way that the public perceives them - if we present the numbers in scientific notation and make a big point of how large they are then the public will be alarmed because we're making it sound alarming. And if we use the verbal equivalent of engineering notation (mega, giga, etc.) and explain - even briefly - that it's not a lot of activity (e.g. it's only a couple of tens of MBq) then the public will by and large accept that. There will always be alarmists and the radio-phobic will always be among them - but they're going to be alarmed by ANY number, couched in scientific notation or not and regardless of the magnitude.

I have to admit that I am far more comfortable with the US units than with SI because I've been using them since the early 1980s, and making the change will force me to do a lot of mental (or calculator) math at first. But the intuition will come with practice - just as I developed a feel for kg, km, liters, and even C once forced to use them often enough. My preference for our current units is based solely on my own intellectual laziness - I have thus far been able to get away without having to develop an intuition about the SI units, so why bother? 

I guess, too, this is a good place to say "My word - if we put as much time into getting used to the new units as we've used to complain about them then the conversion would already be an accomplished fact, rather than an on-going controversy."

Andy

P. Andrew Karam, PhD, CHP
NYPD Counterterrorism Division
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