Thanks, CaptainBlack.

I see that without considering ventilation and other sources of Radon it would be impossible to figure the Radon present in the room, but what I am looking for is the added Radon. How much is given off exclusively by the granite into the volume of air in the kitchen without any air exchange.

I'm a little confused where the 474 pCi came from. The daily total is around 5,600 or so and I am assuming it would need to be divided by 24 to get hourly rate of 233 or so. Am I doing something wrong with my math?

Can I assume that the basic method of figuring the Radon emitted is accurate, not considering air exchange or other Radon imputs?

Thanks for taking the time to help out. It is appreciated.