[ RadSafe ] Radon in granites HPS letter to NYT

[Wes Van Pelt]

Radsafers,

I copied and paste below a paragraph from Dr. Toohey's letter to the NYT on radon in granite counter tops. (http://hps.org/documents/nyt_countertop_toohey-response.pdf )

    "Granite countertop external dose rate measurements that have been reported are about one and a half times greater than background dose rate measurements (or about 20 microroentgen/h). When one goes through the calculations, determining the amount of uranium in the countertop from this measurement and the amount of radon emanating from this), we find an average kitchen ambient radon concentration of 0.13 pCi/L, one‐eighth of the EPA recommended limit and one‐fourth of the natural ambient radon concentration in households across the United States."

Are these ratios correct!!?? I believe Dr. Toohey made an error in the math. I would have said: "... 0.13 pCi/L, 1/32 of the EPA recommended limit and one‐eighth of the natural ambient radon concentration in households..."

Can someone check my math? If we concur, we should notify the HPS ASAP.

Thanks.

Best regards,  Wes
Wesley R. Van Pelt, PhD, CIH, CHP 
Wesley R. Van Pelt Associates, Inc.