Assertion: hydrogen sulfide's concentration | /r/AtLocation | saint john
Facets:
value: between august
type: TEMPORAL
Source sentences:
text: Between August 2013 and August 2016, an average hourly concentration of total reduced sulfur of less than 1 ppb (less than 1.4 μg/m3) was reported in Saint John, New Brunswick, of which up to 60% may be hydrogen sulfide (New Brunswick 2016; Environment Canada 2004b).