An air purifying hat comprises a hat body, a supporting frame and a PCI (plasmacluster ion) generator. The hat body comprises a front structure and a rear structure. The supporting frame is disposed at the front structure of the hat body. The supporting frame comprises a trench and at least one extension structure. The PCI generator is embedded in the trench. The extension structure is disposed along the front structure of the hat body, and comprises a plurality of openings. The PCI generator produces a PCI airflow. The PCI airflow flows out of the supporting frame through the plurality of openings. The PCI airflow forms a wall of airstream in front of the hat body.一種空氣清淨帽,包含一帽體、一支架以及一負離子產生器。前述帽體具有一前側與一後側。前述支架設置於前述帽體之前側,並具有一嵌槽以及至少一延伸部。前述負離子產生器係嵌置於前述嵌槽中。前述延伸部沿前述帽體之前側設置,且具有複數開孔。前述負離子產生器產生一負離子氣流,並沿前述延伸部經由前述複數開孔送出,使前述負離子氣流在前述帽體之前側形成一負離子氣牆。100‧‧‧空氣清淨帽110‧‧‧帽體111‧‧‧前側111a‧‧‧前板111b‧‧‧帽檐120‧‧‧支架121‧‧‧嵌槽122a、122b‧‧‧延伸部123‧‧‧開孔130‧‧‧負離子產生器131‧‧‧殼體131a‧‧‧進氣口131b‧‧‧出風口
