Assertion: methane's concentration | /r/HasProperty | 70,000 to 100,000 ppm
Facets:
Source sentences:
text: Concentrations of 7% to 10% (70,000 to 100,000 ppm) may cause suffocation, even in the presence of sufficient oxygen, manifesting as dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour.