Section 096-100-16 - Baseline concentration"Baseline concentration" means the actual ambient air quality which existed in an area as of: August 7, 1977, for SO2and PM10, February 8, 1988, for nitrogen dioxide (NO2) and October 20, 2010 for PM2.5represented as follows:
A. For Attainment Areas: (1) For sulfur dioxide (SO2) and PM10, this term shall include the actual emissions representative of SO2 and PM10 sources in existence on August 7, 1977, and the allowable emissions of sources which commenced construction before January 6, 1975, but were not in operation by August 7, 1977.(2) For nitrogen oxides (NOx) (measured as NO2), this term shall include the actual emissions representative of sources in existence on February 8, 1988. For sources starting operation after February 8, 1985, but prior to February 8, 1988, representative emissions shall be determined after three years of operation and be based on two years of actual emissions more representative of normal operation. NOx sources commencing construction by February 8, 1988, but not in operation by that date shall use allowable emissions for baseline concentration until three years after start of operations at which time actual emissions more representative of normal operation for that source shall be determined and used for baseline concentration. The actual NOx (measured as NO2) emissions increases or decreases at any source occurring after February 8, 1988, shall not be included in the baseline concentration but shall be included in the determination of the increment consumed, except as specified in the previous paragraph.
(3) For PM2.5, this term shall include the actual emissions representative of sources in existence on October 20, 2010. The actual PM2.5 emissions increases or decreases at any source occurring after October 20, 2010, shall not be included in the baseline concentration but shall be included in the determination of the increment consumed.
B. For Nonattainment Areas: (1) For areas designated nonattainment at the baseline date(s), baseline concentration means the actual ambient air quality that exists in the affected areas at the date the DEP receives the first major new source or major modification application after the date EPA approves the designation of the area to attainment.(2) The following SO2 and PM10 emissions shall not be included in the baseline concentration but shall be included in the determination of the applicable maximum allowable increases:(a) Actual emissions from any source on which construction commenced between January 6, 1975 and August 7, 1977; and(b) Actual emission increases and decreases at any source occurring after August 7, 1977. NOTE: This term identifies which emissions are included in baseline; all other emission increases consume increment. (Increment is defined as a maximum allowable increase in concentration of SO2, PM10, PM2.5, and NO2 over the baseline concentration of such pollutant.) It may not be necessary to determine baseline concentration. It is only necessary to determine that sufficient increment is available and that ambient air quality standards will be met. All increases in actual emissions over base year emissions, including increases in operating rates or hours, consume increment. The term does not define baseline area the same as specified in federal regulations since the SO2 and PM10; August 7, 1977, the NOx; February 8, 1988, and the PM2.5; October 20, 2010 dates are uniform on a statewide basis.
06- 096 C.M.R. ch. 100, § 16