W. Va. Code § 17C-13A-9: Preemption.

(a) The provisions of this article preempt and supersede a local ordinance or rule concerning the subject matter of this article.

(b) This article does not prevent the Department of Environmental Protection as set forth in chapter twenty-two of this code from regulating motor vehicle emissions pursuant to the provisions of section fifteen, article five, chapter twenty-two of this code and any legislative rules promulgated pursuant to that section.