If the Compliance Officer or Council finds that any person is causing or contributing to air pollution which requires immediate action to protect the public health or safety, the Compliance Officer or Council shall order such person to reduce or discontinue immediately the air pollution and cause such order to be served in the manner for commencing a civil action in District Court, and such order shall be complied with immediately. Upon issuing such order, the Council or Compliance Officer, if requested in writing by the person so ordered, shall fix a time and a place for a hearing to be held within a reasonable time thereafter. Not more than 24 hours after the conclusion of such hearing, the order shall be affirmed, modified or set aside.