The commission, the Texas Department of Transportation, and the Public Safety Commission may, subject to federal limitations:
(1) encourage counties likely to exceed federal clean air standards to implement voluntary:
(A) motor vehicle emissions inspection and maintenance programs; and
(B) low-income vehicle repair assistance, retrofit, and accelerated vehicle retirement programs;
(2) establish incentives for counties to voluntarily implement motor vehicle emissions inspection and maintenance programs and low-income vehicle repair assistance, retrofit, and accelerated vehicle retirement programs; and
(3) designate a county that voluntarily implements a motor vehicle emissions inspection and maintenance program or a low-income vehicle repair assistance, retrofit, and accelerated vehicle retirement program as a "Clean Air County" and give preference to a county designated as a Clean Air County in any federal or state clean air grant program.