Assertion: ethane | /r/CapableOf | occur as a trace gas
Facets:
value: in the earth's atmosphere
type: LOCATION
Source sentences:
text: Ethane occurs as a trace gas in the Earth's atmosphere, currently having a concentration at sea level of 0.5 ppb, though its preindustrial concentration is likely to have been only around 0.25 part per billion since a significant proportion of the ethane in today’s atmosphere may have originated as fossil fuels.
text: Ethane occurs as a trace gas in the Earth's atmosphere, having a concentration at sea level of around 0.5 ppbv at present, though its pre-industrial concentration is likely to have been substantially less as a large proportion of the ethane in today's atmosphere probably originated as unburned fossil fuels.