FL DOH / EPA study radon Southwest Florida

[Brian A. MacNeish]

Originally Posted by gromicko

Except for the one that analyzes charcoal kits. Modesty prevents me from telling you who wrote that algorithm .

Anyway, the problem with commercial buildings isn't typically solved by increasing air exchange. You could double the air exchange rate and only cut the radon level in half by dilution. The problem stems from commercial buildings operating under negative presssure due to, mostly, stack effect.

But if the radon source is not the geology beneath the structure, the chimney/stack effect will not be introducing much, if any, radon into interior spaces. One of the radon consultants mentioned above claims sometimes only a few hours of air exchange per day are enough to lower radon concentrations to or below recommended maximum limits.

[Nick Gromicko]

Brian writes

One of the radon consultants mentioned above claims sometimes only a few hours of air exchange per day are enough to lower radon concentrations to or below recommended maximum limits.

What does he mean by "a few hours of air exchange"? Makes no sense. That isn't a rate of exchange.

The question isn't does the air exchange, all buildings exchange air. What matters is change in current rate. Increase the rate from its current rate and the radon levels lowers. Increase it some more and the radon level lowers some more.

Now if it is a tight building, lowering radon by increasing exchange rate becomes easy because the rate can be increased dramatically, but if the exchange rate is already high, lowering radon by increasing exchange rate becomes difficult because the change in rate will be less dramatic.

[Brian A. MacNeish]

Originally Posted by gromicko

Brian writes

What does he mean by "a few hours of air exchange"? Makes no sense. That isn't a rate of exchange.
It is a nebulous term but it could be timed at 10 minutes per hour for 24 hours or 5 min every 30 min. Therefore a total of 4 hours of air exchange occur each and every day. Enough to keep levels below the recommendations, maybe. These folks seem to be knowledgeable people!!

Just found this on one of their sites: "Typically MV (mechanical ventilation) systems are installed on a timer device to cycle the fan on and off introducing a very controlled amount of fresh outside air."


The question isn't does the air exchange, all buildings exchange air. What matters is change in current rate. Increase the rate from its current rate and the radon levels lowers. Increase it some more and the radon level lowers some more.

Now if it is a tight building, lowering radon by increasing exchange rate becomes easy because the rate can be increased dramatically, but if the exchange rate is already high, lowering radon by increasing exchange rate becomes difficult because the change in rate will be less dramatic.

The last part is true but these buildings seem not to need a lot of extra exchange since it was implied many were built since the 1970's and may be fairly tight......Hasn't this, in fact, been part of the problem with raised radon levels- too little "natural" ( I hate that term; we now know better- it's not dependable) ventilation coupled with radioactive concrete.