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National Ambient Air Quality Standards National Ambient Air Quality Standards

and State Implementation Plansand State Implementation Plans

North Carolina Division of Air QualityNorth Carolina Division of Air Quality

Air Quality CommitteeJanuary 8, 2014

Sushma Masemore, P.E.Planning Section Chief

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Key Acronyms

• CAA – Clean Air Act

• NAAQS – National Ambient Air Quality Standards

• SIP – State Implementation Plan

• CFR – Code of Federal Regulations

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NAAQS – National Ambient Air Quality Standards

• Clean Air Act -> EPA -> NAAQS• 6 “criteria pollutants”

– Particulate Matter (PM2.5, PM10)

– Ozone (O3)

– Carbon Monoxide (CO)

– Sulfur Dioxide (SO2)

– Nitrogen Dioxide (NO2)

– Lead

• EPA regulates these pollutants by developing human health-based and environmentally-based criteria for setting permissible levels.

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NAAQS – National Ambient Air Quality Standards

• Primary– Standards to protect public health, including the health of

“sensitive” populations such as asthmatics, children, and the elderly.

• Secondary– Standards to protect public welfare, including protection

against decreased visibility, damage to animals, crops, vegetation, and buildings.

NAAQS (as of October 2011) http://www.epa.gov/air/criteria.html

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Pollutant[final rule cite]

Primary/ Secondary

Averaging Time Level* Form

Carbon Monoxide[76 FR 54294, Aug 31, 2011] primary

8-hour 9 ppmNot to be exceeded more than once per year

1-hour 35 ppm

Lead[73 FR 66964, Nov 12, 2008]

primary and secondary

Rolling 3 month average

0.15 μg/m3 Not to be exceeded

Nitrogen Dioxide[75 FR 6474, Feb 9, 2010][61 FR 52852, Oct 8, 1996]

primary 1-hour 100 ppb 98th percentile, averaged over 3 years

primary andsecondary Annual 53 ppb Annual Mean

Ozone[73 FR 16436, Mar 27, 2008]

primary and secondary 8-hour 0.075 ppm Annual fourth-highest daily maximum 8-hr

concentration, averaged over 3 years

Particle PollutionDec 14, 2012

PM2.5

primary Annual 12 μg/m3 annual mean, averaged over 3 years

secondary Annual 15 μg/m3 annual mean, averaged over 3 yearsprimary and secondary 24-hour 35 μg/m3 98th percentile, averaged over 3 years

PM10primary andsecondary 24-hour 150 μg/m3 Not to be exceeded more than once per year on

average over 3 years

Sulfur Dioxide[75 FR 35520, Jun 22, 2010][38 FR 25678, Sept 14, 1973]

primary 1-hour 75 ppb 99th percentile of 1-hour daily maximum concentrations, averaged over 3 years

secondary 3-hour 0.5 ppm Not to be exceeded more than once per year

*Units of measure for the standards are parts per million (ppm) by volume, parts per billion (ppb) by volume, and micrograms per cubic meter of air (µg/m3).

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NAAQS Reviews

• CAA requires EPA to review every 5 yrs• Current schedule for ongoing NAAQS reviews (as of

Sept 12, 2013)

EPA Milestone

Pollutant

Ozone Lead NO2 Primary

SO2 Primary

NO2/SO2 Secondary

CO PM

Proposal TBD2014?

2014 Feb 2016

Feb 2017

May 2017 Mid 2017

TBD

Final TBD TBD Nov 2016

Nov 2017

Feb 2018 Mid 2018

TBD

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Designations

• After standards are finalized…EPA must designate areas as meeting (attainment) or not meeting (nonattainment) the standard, or undetermined (unclassifiable).

• Monitoring data are used to determine an area’s design value– Design values are concentration measurements averaged over a

specific time interval and are used in designations and redesignations

• Process– 1 yr after NAAQS: states recommend boundaries and

designations – 120 days prior to final designations: EPA notifies states– 2 yr after NAAQS: EPA makes final designations

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North Carolina’s Current Attainment Status

• Only the Charlotte-Gastonia-Salisbury area is designated nonattainment of the 2008 Ozone NAAQS.

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What is a State Implementation Plan (SIP)?

• An overall air quality plan for attaining or maintaining the NAAQS.– Codified in 40 CFR Part 52, each state has its own subpart– Public given opportunity to review and comment

• Infrastructure SIPs (due 3 years after NAAQS revision)– Shows that the state has the basic air quality management

program to implement the NAAQS

• Attainment/Maintenance SIPs (usually 3 years after nonattainment designation)– Identifies emissions control requirements and associated

rules necessary for attainment or maintenance

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Courtesy; James, 2012

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Redesignations

• State submits a request satisfying specific elements in CAA Section 107, including– Area has attained the NAAQS– Improvement is due to permanent and enforceable emission

reductions– Maintenance plan is approved– All other SIP requirements are met

• Requires EPA rulemaking (codified in Part 52 and Part 81)

• EPA’s final approval redesignates an area from nonattainment to attainment/maintenance

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Thank you.

Questions?