About: http://webisa.webdatacommons.org/421621367

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Other gases, such as carbon dioxide, water vapor, methane, oxides of nitrogen, ozone, and ammonia, are considered trace gases.
http://www.w3.org/ns/prov#wasQuotedFrom	un-spider.org