California Code, Health and Safety Code - HSC § 41504

(a) If, after a public hearing, the state board finds that the program or the rules and regulations of a district will not likely achieve and maintain the state's ambient air quality standards, the state board may establish a program, or portion thereof, or rules and regulations it deems necessary to enable the district to achieve and maintain such ambient air quality standards.

(b) Any program, or portion thereof, or rule or regulation established by the state board for the district shall have the same force and effect as a program, rule, or regulation adopted by the district and shall be enforced by the district.