North Carolina Air Toxics Rule Changes Summary
This document outlines the key provisions of the North Carolina Air Toxics Rule Changes pursuant to Session Law 2012-91. It includes exemptions for sources subject to certain federal regulations, requirements for rule amendments and reviews, and procedures related to toxic air pollutants permitting and emissions. The rules aim to protect human health while optimizing regulatory efficiency.
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Air Toxics Rule Changes (pursuant to Session Law 2012-91) North Carolina Division of Air Quality July 2013 Environmental Management Commission
Acronyms AAL acceptable ambient level GACT generally available control technology MACT maximum achievable control technology SIC standard industrial classification TAP toxic air pollutant TPER toxic permitting emission rate
Air Toxics Summary of SL 2012-91 Section 1 Exempts sources subject to certain federal regulations Codifies Director s Call provision Section 2 Requires rule amendments Section 3 Requires review of rules and their implementation Section 4 Requires reports on implementation of this act
Air Toxics Section 1 Exempts from the State air toxics rules sources of toxic air pollutants subject to certain federal regulations, including: National Emission Standards for Hazardous Air Pollutants (NESHAPs), 40 CFR Part 61 Maximum Achievable Control Technology (MACT) standards, 40 CFR Part 63 Generally Available Control Technology (GACT) standards, 40 CFR Part 63 Subject to case-by-case MACT, 112(j) of the Clean Air Act
Air Toxics Section 1 When DAQ receives a permit application for a new or modified source or facility that would result in a net increase in toxic air pollutants: Requires DAQ to determine if the toxic air emissions would pose an unacceptable risk to human health and if it does, the Division Director would make a written finding and require a permit application that eliminates the unacceptable risk (for all practical purposes this is the existing Director s Call provision)
Air Toxics Section 3 Requires DAQ to review the State air toxics rules and their implementation to determine whether changes could: Reduce unnecessary regulatory burden Increase the efficient use of DAQ resources while maintaining protection of public health Conduct the review in consultation with interested parties Report the results of the review and include recommendations to the ERC by 12/1/12 6
Recommendations for Rule Changes 1. Develop an additional set of emissions thresholds for pollutants coming from unobstructed vertical stacks 2. Exempt natural gas and propane fired boilers 3. Exempt emergency engines 4. Eliminate SIC call 5. Clarify use of actual rate of emissions 6. Remove the term unadulterated wood from rules
1. Develop additional toxic permitting emission thresholds Develop an additional set of emissions thresholds for pollutants coming from unobstructed vertical stacks Additional thresholds approximately 1.3-4.8 times higher than current thresholds Health based standards stay the same.
1. Develop additional toxic permitting emission thresholds TPERs calculated from AAL based on dispersion modeling parameters AAL* (1/(Cmax * averaging time factor)) * hours in averaging period =TPER
1. Develop additional toxic permitting emission thresholds Cmax is maximum emission rate derived from dispersion model using conservative input parameters Emission rate 1 lb/hr Physical stack height=5.0 meters Stack gas temperature=293 degrees Kelvin Stack gas velocity=1.0 m/s Stack diameter=1.0 m Resulting Cmax= 0.9497 grams/sec Averaging Time Factor: Annual=0.1, Daily=0.6
2. Exempt natural gas and propane fired combustion sources US EPA has exempted certain gas-fired combustion units from federal air toxics rules. Another federal rule only prescribes work practice standards on affected units. Toxic air emissions from these sources are well below the TPERs.
2. Exempt natural gas and propane fired combustion sources Reviewed emissions profiles for all TAPs from combustion of natural gas and propane Using emissions estimation spreadsheets, back calculated what heat input would result in emission rate that would exceed an existing TPER Result: Benzene was controlling pollutant exceeding TPER at 450 million BTU/hr
3. Exempt emergency engines US EPA federal air toxics rules apply to all emergency engines and only prescribe work practice standards. Used temporarily in emergency situations. Small. Few hours of operation. Peak shaving engines are not considered emergency engines.
3. Exempt emergency engines Reviewed emissions profiles for all TAPs from combustion of diesel fuel in emergency engines Using emissions estimation spreadsheets, back calculated through iterative process what size unit exceeds an existing TPER Result: Formaldehyde controlling pollutant for hourly emissions at 4843 horsepower
4. Eliminate SIC call 15A NCAC 02Q .0705 provides a mechanism for the Director to require all facilities under the same four-digit Standard Industrial Classification (SIC) to submit an application to comply with the NC air toxics rules. The existing Director s Call rule and SL 2012-91 provide adequate authority to address any unacceptable risks to human health from any facility.
5. Clarify use of actual rate of emissions Clarify in the rule to ensure that DAQ is implementing it consistently.
6. Remove term unadulterated wood from rules Elimination of this term will prevent confusion with definitions for combustion sources in federal rules.
Additional Rule Changes Repeal 15A NCAC 02Q .0705, Existing Facilities, due to elimination of last MACT/GACT provision. Repeal of 15A NCAC 02Q .0714, Wastewater Treatment Systems at Pulp and Paper Mills, due to obsolete requirements and implementation schedules.
Asbestos AAL and TPER Correction Calculation error in original recommendation identified by SAB Old AAL = 2.8 x 10-11 fibers/mL New AAL = the 2.8 x 10-6 fibers/mL Old TPER = 1.9 X 10-6 lb/year New TPER = 5.7 x 10-3 lb/year No impact no facilities in NC
Impacts Average 94 permit applications per year submitted to DAQ Section 1 - 34 facilities/year Recommendation 1 16 facilities/year Recommendation 2 20 facilities/year Recommendation 3 15 facilities/year No impacts estimated for recommendations 4, 5 and 6
Fiscal Impacts Reduced facility data collection costs Reduced facility modeling costs $147,000 savings per year o Increased DAQ staff time due to unacceptable risk determinations $6400 opportunity cost per year o
