The state board may also exempt, from the schedule of installation adopted pursuant to Section 43655, any motor vehicle registered to an owner whose residence is in a county, or portion thereof, which the state board finds, after a public hearing, that the installation of a certified device pursuant to Section 43652 to control exhaust emissions is not necessary or desirable to preserve and protect the public health and the existing ambient air quality thereof.
Ca. Health and Saf. Code § 43657