Gas stations emit VOCs such as gasoline vapors, and they were in high need of management as they are often located close to residential areas. To address this matter, prevention facilities were installed in gas stations situated in air conservation special countermeasure areas and air quality control areas. Installation was completed for Stage I (from manufacturing facilities to gas station storage facilities) by 2004 and for Stage II (from gas station storage facilities to filling vehicle fuel tanks) from 2007 to 2012.