(a) The requirements of subpart G and § 51.281 of this chapter are not met since the plan does not provide the degree of control necessary to attain and maintain the national standards for particulate matter in Gila, Maricopa, Pima, Pinal, and Santa Cruz Counties. Therefore, Regulation 7-1-3.6 (process industries) of the Arizona Rules and Regulations for Air Pollution Control is disapproved for Gila, Maricopa, Pima, Pinal, and Santa Cruz Counties.

(b) Replacement regulation for Regulation 7-1-3.6 of the Arizona Rules and Regulations for Air Pollution Control (Gila, Maricopa, Pima, Pinal, and Santa Cruz Counties). (1) No owner or operator of any stationary process source in Gila, Maricopa, Pima, Pinal, or Santa Cruz County shall discharge or cause the discharge of particulate matter into the atmosphere in excess of the hourly rate shown in the following table for the process weight rate identified for such source:

(2) Paragraph (b)(1) of this section shall not apply to incinerators, fuel burning installations, or Portland cement plants having a process weight rate in excess of 250,000 lb/h.

(3) No owner or operator of a Portland cement plant in Gila, Maricopa, Pima, Pinal, or Santa Cruz County with a process weight rate in excess of 250,000 lb/hr shall discharge or cause the discharge of particulate matter into the atmosphere in excess of the amount specified in § 60.62 of this chapter.

(4) Compliance with this paragraph shall be in accordance with the provisions of § 52.134(a).

(5) The test methods and procedures used to determine compliance with this paragraph are set forth below. The methods referenced are contained in the appendix to part 60 of this chapter. Equivalent methods and procedures may be used if approved by the Administrator.

(i) For each sampling repetition, the average concentration of particulate matter shall be determined by using method 5. Traversing during sampling by method 5 shall be according to method 1. The minimum sampling time shall be 2 hours and the minimum sampling volume shall be 60 ft 3 (1.70 m 3), corrected to standard conditions on a dry basis.

(ii) The volumetric flow rate of the total effluent shall be determined by using method 2 and traversing according to method 1. Gas analysis shall be performed using the integrated sample technique of method 3, and moisture content shall be determined by the condenser technique of method 4.

(iii) All tests shall be conducted while the source is operating at the maximum production or combustion rate at which such source will be operated. During the tests, the source shall burn fuels or combinations of fuels, use raw materials, and maintain process conditions representative of normal operation, and shall operate under such other relevant conditions as the Administrator shall specify.

(c) The requirements of § 51.281 of this chapter are not met since the plan does not contain regulations for Mohave and Yuma Counties in the Mohave-Yuma Intrastate Region or Pinal-Gila Counties in the Central Arizona Intrastate Region which provide enforceable and reproducible test procedures for the determination of compliance with the emission standards. Therefore paragraph C of section 3, regulation 2 (Particulates: Other Sources) of the Mohave County Air Pollution Control Regulations, paragraph B of regulation 8-1-3.6 (Particulates—Process Industries) of the Yuma County Air Pollution Control Regulations, and paragraph C of regulation 7-3-1.4 (Particulate Emissions—Incineration) and paragraph F of regulation 7-3-1.7 (Particulate Emissions—Fuel Burning Equipment) of the Rules and Regulations for Pinal-Gila Counties Air Quality Control District are disapproved.

(d) Pursuant to CAA section 110(k)(5), the State of Arizona is required to submit a revision to the Arizona SIP for the Yuma PM10 nonattainment area (NAA) to the EPA by November 17, 2023. The SIP revision must, among other elements, provide for attainment of the 24-hour PM10 NAAQS in the Yuma NAA as expeditiously as practicable but no later than December 31, 2027.

(e) Effective August 21, 2023, the EPA has determined that the West Pinal Serious PM10 nonattainment area failed to attain the 1987 24-hour PM10 NAAQS by the applicable attainment date of December 31, 2022. This determination triggers the requirements of CAA sections 179(d) and 189(d) for the State of Arizona to submit a revision to the Arizona SIP for West Pinal to the EPA by December 31, 2023. The SIP revision must, among other elements, demonstrate expeditious attainment of the 1987 PM10 NAAQS within the time period provided under CAA section 179(d) and provide for an annual reduction in the emissions of direct PM10 or a PM10 plan precursor pollutant within the area of not less than five percent until attainment.