If you have granite countertops and want to test them for radon place a short term home radon test kit near the granite and another kit in the basement or lowest usable level of the home.
Marble have radon.
While natural rocks such as granite may emit radiation and radon gas the levels attributable to such sources are not typically high.
The uranium breaks down on exposure to air forming radon gas.
Radon is a colorless and odorless toxic gas linked to lung cancer.
November 2013 thanks to quick and forceful action by the marble institute of america and its legal team the doctor s show has retracted a show segment in which it reported that living in a home with granite countertops could be as bad as smoking a half package of cigarettes a day.
You would not expect to have radon produced from exposure of marble to air.
There are many do it yourself radon test kits available through retail outlets and on line starting at about 25.
The doctors show admits it erred in granite radon segment.
Over years of exposure radon can cause cancer the primary health concern with this gas.
However some articles have circulated that claim granite is a source of harmful radiation specifically radon.
For some objective information on the subject check the latest recommendations from the u s.
Radon can be found in soil rock air and even water.
If the levels of radon in the area containing the granite are higher than your indoor levels in another area of your home and the surface top test devices also return high results then it is possible that the granite is contributing to or is the source of your indoor radon levels.
Radiation and radon are generally lower in marbles but both marble and granite has been studied for many years on these issues.
To reduce the radon risk you should first test the air in your home to determine the radon level.
When materials such as granite are mined from the earth they naturally contain these radioactive elements and may occasionally emit radon gas.
Some granite samples and countertops have been tested and some have shown elevated levels of radon emissions.
Environmental protection agency epa and the american association of radon scientists and technologists aarst.
It is relieving to hear that the radioactive levels in granite and marble are too small to be of any concern but all construction materials in general emit a small amount of radon gas which is radioactive and can easily accumulate in poorly ventilated buildings.
Granites from india and egypt have very low emanation rates and are by far the best in the world in this regard.
Marble is dominantly calcium carbonate and is very depleted in uranium.
Here is a link for several studies from all over the world.
Here is the truth about granite countertops and radiation.