EPA is approving a State Implementation Plan (SIP) revision submitted by the State of Maryland which amends Code of Maryland Administrative Regulations (COMAR) 26.11.01.01, 26.11.02.10 (C)(9), and 26.11.06.14. The intended effect of this action is to approve an amendment to Maryland's Prevention of Significant Deterioration (PSD) program. This revision makes these regulations consistent with the currently effective version of 40 CFR part 52.21, including establishing the maximum increases in ambient particles with an aerodynamic diameter of less than or equal to a nominal 10 micrometers (PM-10) concentration allowed in an area above the baseline concentrations. This action is being taken in accordance with section 110 of the Clean Air Act (CAA), and in satisfaction of the June 3, 1993 promulgation of the PM-10 increment regulations requiring that existing state PSD programs be modified to replace the total suspended particulate (TSP) increments with the new PM-10 increment provisions.