About: http://webisa.webdatacommons.org/118423396

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	Therefore, in order to minimize health and other hazards, and to ensure efficient airflow, it is necessary for ventilation ducts to be cleaned periodically to remove the deposited debris.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com