26.11.16.02

.02 Demonstrating Compliance with COMAR 26.11.15.06.

A. Screening Analysis.

(1) Carcinogenic Effects. A person may demonstrate that emissions of a Class I TAP from a premises will not unreasonably endanger human health because of potential carcinogenic effects by a screening analysis showing that total allowable emissions from the premises will not cause increases in ambient levels that exceed the risk-based screening level for the TAP.

(2) Other Toxic Effects.

(a) A person may demonstrate that emissions of a Class I or Class II TAP from a premises do not unreasonably endanger human health because of potential toxic effects other than cancer by a screening analysis showing that total allowable emissions from the premises will not cause increases in ambient levels that exceed applicable TLV-based, threshold-based, or special screening levels.

(b) If a special screening level has been adopted, a TLV-based or threshold-based screening level may not be used for that TAP. A threshold-based screening level may be used only if there is no TLV, no special screening level, and no acceptable ambient level for a TAP.

(3) For a screening analysis, a person may use the dispersion modeling procedures in Air Management Administration Technical Memorandum 86-02 (TM 86-02), "Ambient Air Quality Impact Screening Analysis for Toxic Air Pollutants", which is incorporated by reference, or other, more rigorous dispersion modeling procedures as provided in §C(1)(a) of this regulation. If concentrations predicted using TM 86-02 exceed applicable screening levels, more rigorous modeling techniques should be used in either a screening analysis or a more detailed analysis.

(4) Instead of using dispersion modeling, a person may conduct a screening analysis by showing that total allowable emissions of a TAP will be less than the most stringent applicable emission rate listed in the tables in this section. Multiple screening levels with different averaging periods may apply to a TAP. These tables may not be used with screening levels having averaging periods other than those listed in the tables. Emission rates labeled "10 Meter Stacks, No Downwash" may be used only if all emissions of the TAP are discharged from a stack or stacks at least 32.8 feet (10 meters) high under conditions preventing downwash. (TM 86-02 describes conditions causing downwash.) Except as provided in COMAR 26.11.15.06, these emission rates apply to the total allowable emissions from a premises.

Screening Level Premises Emission Rate (10 Meter Stacks and No Downwash) Premises Emission Rate (Shorter Stack, Possible Downwash, or Fugitive)
Annual (micro-grams/ cubic meter) (lb./yr.) (kg/yr.) (lb./yr.) (kg/yr.)
0.001—0.0099 1.66 0.75 0.36 0.16
0.01—0.099 16.64 7.53 3.65 1.65
0.1—0.99 166.44 75.39 36.52 16.54
1.0—10 1664.40 753.97 365.29 165.47
Greater than 10 16644.00 7539.73 3652.92 1654.77
8-Hour or 1-Hour (micrograms/ cubic meter) (lb./hr.) (kg/hr.) (lb./hr.) (kg/hr.)
1—9.9 0.01 0.007 0.003 0.001
10—29.9 0.16 0.07 0.04 0.01
30—59.9 0.49 0.22 0.10 0.04
60—99.9 0.98 0.44 0.21 0.09
100—129.9 1.60 0.70 0.36 0.16
130—250 2.12 1.00 0.46 0.21
Greater than 250 4.07 1.80 0.89 0.40

B. Second Tier Analysis.

(1) Carcinogenic Effects. A person may demonstrate that emissions of a Class I TAP from a premises will not unreasonably endanger human health because of potential carcinogenic effects by a second tier analysis showing that total allowable emissions from the premises will not cause increases in ambient levels that exceed an insignificant risk concentration (IRC) for the TAP, or by an approvable request for a special permit under Regulation .05 of this chapter. A second tier analysis would be appropriate if new information is available concerning carcinogenic dose-response relationships. A special permit should be requested if a person wishes to more accurately characterize exposure, to justify approval of risks greater than 1 10-5, or to otherwise modify assumptions to more accurately represent risks.

(2) Other Toxic Effects. A person may demonstrate that emissions of a Class I or Class II TAP from a premises will not unreasonably endanger human health because of toxic effects other than cancer by a second tier analysis showing that total allowable emissions from the premises will not contribute to concentrations exceeding the applicable acceptable ambient level (AAL) for the TAP.

C. General Procedures for Compliance Demonstrations.

(1) Dispersion Modeling Procedures Required.

(a) A person using dispersion modeling to demonstrate compliance with COMAR 26.11.15.06 shall use procedures approved by the Department. The Department will approve dispersion modeling procedures that are consistent with the U.S. Environmental Protection Agency's guidance on dispersion modeling.

(b) For second tier analysis showing that total allowable emissions from a premises will not contribute to concentrations exceeding an acceptable ambient level, a person shall use available emissions data to model ambient impacts caused by other sources of the Class II TAP within 5 kilometers (3.1 miles) of the premises. The Department will assist persons modeling ambient concentrations for comparison to AALs by providing available information on emissions from other sources or on background levels. The Department may provide additional assistance as resources permit.

(2) Averaging Times. To demonstrate compliance with this chapter, a person shall use the averaging time consistent with the applicable screening level, AAL, or IRC unless the Department requires the use of a shorter averaging time. The Department will require that a shorter averaging time be used if it determines that the operating procedures of the source may cause a high concentration of a TAP for a short period and that consideration of potential health effects due to peak exposures may be warranted for the TAP.