Required SIP Elements by Nonattainment Classification
NOTE: Transportation and General Conformity apply in all ozone nonattainment areas.
Marginal (3 years to attain):
- Baseline emission inventory (EI), followed by periodic EI updates
- New source review (NSR) program
- NSR offset ratio 1.1:1
- Major source emission statements
- Major source threshold 100 tons per year (tpy)
Moderate (6 years to attain):
- All requirements for Marginal classification, with
- Major source threshold 100 tpy
- NSR offset ratio 1.15:1
- Major source volatile organic compounds/nitrogen oxides (VOC/NOx) reasonably available control technology (RACT)
- Attainment demonstration
- 15% reasonable further progress (RFP) over 6 years
- Basic emissions inspection and maintenance (I/M) program
- Contingency measures for failure to attain
- Stage II gasoline vapor recovery
Serious (9 years to attain):
- All requirements above, with
- Major source threshold 50 tpy
- NSR offset ratio 1.2:1
- 18% RFP over 6 years
- Enhanced monitoring plan
- Modeled demo of attainment
- Milestone contingency measures for RFP
- Enhanced I/M
- Clean fuels program (if applicable)
- NSR requirements for existing source MODS
- Vehicle miles traveled (VMT) demonstration, and transportation control measures if needed
Severe (15 or 17 years to attain)
- All requirements above, with
- Major source threshold 25 tpy
- NSR offset ratio 1.3:1
- VMT growth offset
- Low VOC reformulated gas
- Penalty fee program for major sources
Extreme (20 years to attain)
- All requirements above, with
- Major source threshold 10 tpy
- NSR offset ratio 1.5:1
- Clean fuels requirement for boilers
- Transportation congestion controls