Assertion: ethane | /r/HasAspect | concentration
Facets:
value: at present
type: TEMPORAL
value: currently
type: TEMPORAL
value: at sea level of 0.5 ppb
type: OTHER
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.