curie (Ci) examples

As an example, the specific activity of natural uranium is listed as
26 x 10^-9 TBq/g   0.71 x 10^-6 Ci/g  =  710 nCi/g
    ( note that the T prefix means 10^12 )
natural uranium26 Bq/mg 0.7 Ci per ton (Metric)
Some isotopes of interest:
americium 241 0.13 TBq/g 3.4 Ci/g
iodine 131 4.6 TBq/mg 120 Ci/mg
thallium 201 7.9 TBq/mg 210 Ci/mg
cobalt 60 42 TBq/g 1.1 Ci/mg
carbon 14 in air0.04 Bq/liter of air1 pCi/liter of air
( The p prefix is 10^-12 )
For comparison the EPA limit for radon is 6 pCi/liter of air.