Assertion: fluorine's odor | /r/HasProperty | as 20 ppb
Facets:
Source sentences:
text: Free fluorine has a characteristic pungent odor, detectable at concentrations as low as 20 ppb.
text: The free element has a characteristic pungent odor, detectable in concentrations as low as 20 ppb, which is below the safe working level.
text: The free element has a characteristic pungent odor, detectable in concentrations as low as 20 ppb, which is below the safe working level.