Assertion: acid rain | /r/HasAspect | ph of less than 5.6
Facets:
value: usually
type: TEMPORAL
Source sentences:
text: But this is not enough to call it acid rain (acid rain must have pH of less than 5.6 ).
text: Acid rain usually has a pH of less than 5.6.
text: Acid precipitation has a pH of less than 5.6 (the normal acidity of unpolluted atmospheric water) and is often less than pH 5.0.