Non-Attainment 

New Source Review (NA-NSR)

Requirements

US Environmental Protection Agency

Office of Air Quality Planning and Standards

RTP, NC
What is the purpose of this NA-NSR 

discussion?

To gain better understanding of the NANSR: 

Requirements

Definitions & Key Terms
Details about NA-NSR

Requirements
What are the major NA-NSR program 

requirements?

LAER (Lowest Achievable Emission Rate)

Offsets at prescribed ratios

Alternative sites analysis

Statewide facility compliance

Public Involvement
What is the Lowest Achievable Emission 

Rate (LAER)?

Most stringent emission limitation for such 

category or source:

Continued in the implementation plan or

Achieved in practice

Does not consider economic, energy of 

other environmental factors

Cannot be less stringent than any NSPS
What is the Lowest Achievable Emission 

Rate (LAER)? (continued)

Generally expressed as:

Numerical emissions limit (lb/MMBtu) or

Emissions rate (lb/hr)

Emissions rate could result from one or a 

combination of:

Changes in raw materials processed

Process modifications

Add-on controls
What other things can be considered for 

establishing a LAER limit?

Technology transfers from other:

Gas stream controls

Classes or categories producing similar gas streams

Process controls and modifications

That are similar to the source category in question
Where can you find information about 

previous LAER limits?

Implementation plan limits for particular 

class/category of sources or the sources 

themselves

Preconstruction/operating permits issued 

in other nonattainment areas

RACT/BACT/LAER Clearinghouse
What is the process for demonstrating 

that a certain LAER limit is unachievable?

 Source noncompliance with an 

implementation plan limit doesn’t 

automatically demonstrate limit is 

unachievable

1. Determine specific reasons for noncompliance

2. Assess ability of the source to comply
What are emissions “offsets”?

Emissions reductions from existing 

sources to stabilize emissions

Sources must obtain offsets as a condition 

for permit approval

Developed in accordance with applicable 

State or local NA rules.
What is the purpose of obtaining offsets?

Allow industrial growth while moving area 

towards attainment of NAAQS

Demonstration that area will attain the NAAQS 

not needed

Provide positive air quality benefit
What are the factors considered for 

obtaining offsets?

Pollutants requiring offsets & amount 

offset required

Location of offsets relative to proposed 

source

Allowable sources for offsets

“Baseline” for calculating emissions 

reduction credits

Enforceability of proposed offsets
Which pollutants require offsets and what 

are they?

Nonattainment Areas

Pollutant Nonattainment Classification Offset Ratio

Ozone Marginal (≥ 0.085 < 0.092 ppm) 1.1 to 1

Moderate (≥ 0.092 < 0.107 ppm) 1.15 to 1

Serious (≥ 0.107 < 0.120 ppm) 1.2 to 1

Severe (≥ 0.120 < 0.187 ppm) 1.3 to 1

Extreme (= 0.187 ppm and up) 1.5 to 1

Particulate Matter (10μm) Moderate -

Serious -

Carbon Monoxide Moderate (9.1 – 16.4 ppm) -

Serious (16.5 and up ppm) -

Sulfur Dioxide, Nitrogen Oxides 

and Lead

No nonattainment classifications exist -
Where should offsets be located relative 

to the proposed source?

Sources of offsets should impact air 

quality in the same general area as the 

proposed source

Offsets from the same air quality control region 

acceptable

Showing of air quality improvement at each 

location affected by the proposed source not 

needed
Which offset sources are not allowed?

Emissions reductions:

resulting from other regulatory actions

counted in major modification “netting” 

Exception: 

Emissions reductions validly “banked” under 

approved implementation plan
How is the offset baseline calculated?

Offsets will be based on emissions 

reductions below implementation plan 

limits in effect at time of permit application

Applicant required to use actual emissions 

as baseline when no meaningful or 

applicable implementation plan 

requirement exists
What are the enforceability provisions of 

the proposed offsets?

Acceptable offsets must be:

Creditable

Quantifiable

Federally enforceable

Permanent
What are the alternative site analysis 

requirements?
What are the requirements for statewide 

facility compliance?

Other major sources in the same State 

under the control of the owner /operator of 

proposed source must be:

In compliance with or 

On schedule for compliance with all emission 

limitations & standards of the CAA

See CAA section173(a)(3)
What are the public involvement 

requirements?

Reviewing authority must:

Prepare a draft permit

Provide adequate public notice to affected 

community and general public

Provide 30-day public comment period on draft 

permit

Provide opportunity for public hearing on draft 

permit