Assertion: acid rain's level | /r/HasProperty | acidic
Facets:
value: as parts of the northern hemisphere
type: LOCATION
value: in nature
type: LOCATION
Source sentences:
text: The main cause for acid rain is the presence of high levels of oxides of sulphur and nitrogen, which are already acidic in nature.
text: These levels are as acidic as parts of the Northern Hemisphere, but are caused naturally by emissions from native tropical plants, rather than through any sort of human activities.