§51.112. Demonstration of adequacy. — Inbound Citations

(c) An attainment demonstration due pursuant to paragraph (a) or (b) of this section must meet the requirements of § 51.112; the adequacy of an attainment demonstration shall be demonstrated by means of a photochemical grid model or any other analytical method determined by the Administrator, in the Administrator's discretion, to be at least as effective.

In addition to other requirements in §§ 51.100 through 51.116 the following requirements apply to lead. To the extent they conflict, there requirements are controlling over those of the proceeding sections.

(c) An attainment demonstration due pursuant to paragraph (a) or (b) of this section must meet the requirements of § 51.112; the adequacy of an attainment demonstration shall be demonstrated by means of a photochemical grid model or any other analytical method determined by the Administrator, in the Administrator's discretion, to be at least as effective.

(1) For urbanized areas with measured lead concentrations in excess of 4.0 µg/m 3, quarterly mean measured since January 1, 1974, the plan must employ the modified rollback model for the demonstration of attainment as a minimum, but may use an atmospheric dispersion model if desired, consistent with requirements contained in § 51.112(a). If a proportional model is used, the air quality data should be the same year as the emissions inventory required under the paragraph e.

(e) In the absence of adequate monitoring data, appropriate models must be used to classify an area under paragraph (b) of this section, consistent with the requirements contained in § 51.112(a).

(b) The requirements of § 51.112(a) of this chapter are not met because the State did not submit an adequate control strategy demonstration to show that the Maryland Regulation 10.03.36.04B (1) and (2) would not interfere with the attainment and maintenance of the national sulfur dioxide standards.