Assertion: radon | /r/AtLocation | higher levels
Facets:
Source sentences:
text: It can be found at higher levels in the air in houses and other buildings, as well as in water from underground sources, such as well water.
text: It can also be found in higher levels in the air in houses and other buildings, and in smaller concentrations in water sources such as wells.
text: It can be found at higher levels in the air in houses and other buildings, as well as in water from underground sources, such as well water.