(a) This section applies only to a contract to be performed, wholly or partly, in a nonattainment area or in an affected county, as those terms are defined by § 386.001, Health and Safety Code.
(b) The comptroller and state agencies procuring goods or services may:
(1) give preference to goods or services of a vendor that demonstrates that the vendor meets or exceeds any state or federal environmental standards, including voluntary standards, relating to air quality; or
(2) require that a vendor demonstrate that the vendor meets or exceeds any state or federal environmental standards, including voluntary standards, relating to air quality.

(c) The preference may be given only if the cost to the state for the goods or services would not exceed 105 percent of the cost of the goods or services provided by a vendor who does not meet the standards.