Assertion: propane | /r/HasProperty | mixed with air
Facets:
value: properly
type: MANNER
value: to form a combustible mixture
type: PURPOSE
Source sentences:
text: It also offers additional air quality advantages: when properly mixed with air to form a combustible mixture, propane emits virtually no soot, and low carbon monoxide, hydrocarbons, and oxides of nitrogen, which are the basic precursors of ground-level ozone, or smog.