Assertion: acid rain's ph value | /r/HasProperty | measured for rainfall
Facets:
value: in europe
type: LOCATION
value: in the united states
type: LOCATION
Source sentences:
text: While pH values as low as 2 and 3 have been measured for rainfall in the United States and Europe, by the year 2000 the most acidic precipitation in the United States had an average pH of 4.3.