About: http://webisa.webdatacommons.org/325238254

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	However, other gases including oxygen (O2), nitrogen (N2), nitrous oxide (N2 O), ammonia (NH4), methane (CH4) and propane (CH3 CH2 CH3) may be added if desired.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com