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/NO_x) reasonably available control technology (RACT)
  • See Control Techniques Guidelines (CTGs) and Alternative Control Techniques (ACTs)
• 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