Assertion: acid rain's acid | /r/AtLocation | small quantities
Facets:
value: from biological decay
type: OTHER
value: naturally
type: MANNER
value: from volcanic activity
type: OTHER
Source sentences:
text: Although sulfuric acid may be produced naturally in small quantities from biological decay and volcanic activity (Figure 1), it is produced almost entirely by human activity, especially the combustion of sulfur-containing fossil fuels in power plants.