## Sulfur Dioxide 

# Sulfur Dioxide Implementation - Programs and Requir ements for Reducing Sulfur Dioxide The Clean Air Act requires EPA to set National Ambi ent Air Quality Standards (NAAQS) for six criteria pollutants; sulfur dioxide (SO 2 ) is one of these. EPA works with partners at state, local, and tribal air quality agencies tomeet these standards. General Information on Designation and Implementati on Requirements State Implementation Plans designed to reduce emiss ions in areas designated as nonattainment will be d ue within 18 months of the effective date of design ation, and the attainment date for nonattainment areas will be wit hin 5 years of designation. Under the Clean Air Act (CAA), as amended in 1990, each state must develop a plan describing how it wi ll attain and maintain the NAAQS. In other words, how it plans to clean up polluted areas and keep them clean. This plan i s called the State Implementation Plan (SIP) and isrequired under Section 110 of the CAA (40 CFR Part51, Subparts F & G). In general, the SIP is a collection of program s, including: a monitoring program, which is a collection of moni toring devices throughout the country which provide actual measurements of the concentrations in the a ir, to identify whether an area is meeting the air quality standard s, and if not, how much reductions are needed to me et those standards; air quality calculations and computer modeling, whi ch are used to predict future trends and the effect s of emissions reduction strategies; emissions inventories, which describe the sources a nd categories of emissions to the air for a given p ollutant, and how much is emitted by each source orsource category; control strategy studies whose goal is finding the best way to reduce emissions in order to meet air q uality standards; formal adoption of measures (enforceable by EPA, St ates and citizens) which ensure that we will achiev e the reductions deemed necessary in the planning p rocess; periodic review to evaluate whether those needed re ductions were achieved in reality, and whether theyhad the predicted result. The air quality agency responsible for the State Im plementation Plan, (usually a state agency) must pr ovide the public an opportunity to review the plan before sending it to EPA for approval. In cases where the EPA fails to approve a state imp lementation plan, the Agency can issue and enforce a Federal Implementation Plan (FIP) to ensure attai nment and maintenance of the NAAQS. In addition, the Clean Air Act contains penalties, referred to as "sanctio ns" which EPA can impose in areas not satisfying th e State Implementation Plan requirements.

EPA establishes data requirements for implementing the 2010 standards for SO2 August 10, 2015 - EPA is establishing a timetable a nd other requirements for state, local and tribal a ir agencies to (1) characterize current air qualityin areas with large sources of sulfur dioxide (SO2) emissions through monitorin g or modeling techniques and (2) provide such air q uality data to the EPA. At a minimum, air agencies must characterize air quality around sources that emit 2,000 tons per yea r or more of SO2. We will use these data to inform future rounds of area designations for the 2010 SO2 National Ambient Air Quality Standard in 2017 and 2020 and for other pur poses. Final Rule (PDF) (139pp, 608kb) Fact Sheet (PDF) (3pp, 37kb) Response to Comments (PDF) (260 pp, 1.8 MB) Webinar presentation slides (PDF) (16pp, 195k) - August 19, 2015 Updated Guidance for Sulfur Dioxide Area Designatio ns March 20, 2015 - This memorandum provides informati on on the schedule and process for designating area s for the 2010 primary sulfur dioxide (SO 2 ) national ambient air quality standard (NAAQS). In addition, it identifie s factors for determining the boundaries for SO 2 areas designated nonattainment, attainment, and un classifiable. EPA recommends that states and tribes consider and addr ess these factors when identifying boundaries for a ny updated area designation recommendations they ch oose to submit for the 2010 SO 2 NAAQS. Updated Guidance (PDF) (11pp, 1.2MB)

Guidance for Sulfur Dioxide Nonattainment Areas April 23, 2014 - EPA is providing guidance to assis t air agencies with implementing the 2010 1-hour Na tional Ambient Air Quality Standard for sulfur diox ide (SO 2 ) in areas designated as nonattainment for the standard. Chil dren, the elderly and people with asthma are susceptible to health problems associated with breathing SO 2 , including narrowing of the airways, which can cause difficult y breathing, and increased asthma symptoms.

Guidance for 1-Hour SO 2 Nonattainment Area SIP Submissions (PDF) (118pp, 9.4 MB) Recorded webinar on the SO 2NAA Guidance presented to State and Tribal air age ncies on May 1, 2014 Presentation slides from the May 1, 2014 webinar (P DF) (16pp, 135k) EPA Proposes Options to Assess Sulfur Dioxide Air Q uality April 17, 2014 - After carefully considering input from a broad range of stakeholders, EPA is proposin g options that would allow state and local air agen cies to use air quality monitoring or modeling to determine whether areas a cross the United States meet the 2010 air quality s tandards for sulfur dioxide. http://www.epa.gov/airquality/sulfurdioxide/impleme nt.html 

# Sulfur Dioxide Implementation | Sulfur Dioxide | US EPA http://www.epa.gov/airquality/sulfurdioxide/imp lement.html

1 of 3 8/31/2015 9:41 AMProposed Rule (PDF) (28pp, 504k) - Federal Register - May 13, 2014

Fact Sheet (PDF) (5pp, 138k) Recorded webinar on the proposal held May 13, 2014 Presentation slides from May 13, 2014 webinar (PDF) (14pp, 307k) EPA Updates Monitoring and Modeling Technical Assis tance Documents for Implementing the 2010 Sulfur Di oxide Standard January 7, 2014 - EPA is making available two updat ed draft documents that provide technical assistanc e for states implementing the 2010 health-based, su lfur dioxide (SO 2 ) standard. These documents provide technical advice on the use of modeling and monitoring to determineif an area meets the 2010 SO 2 air quality standard. EPA appreciates the comments it received on the May2013 drafts of these documents. Many of those com ments have been addressed, others referred to parts of EPA’s forthcoming proposed Data Requirements Rule for Imp lementing the 1-Hour SO2 standard. To allow for further comments once that rule is proposed, EPA plans to make an updated version of these documents available around the time the Data Requirements Rule is finalized. Sulfur Dioxide (SO 2 ) National Ambient Air Quality Standards Designatio ns Modeling Technical Assistance Document (December2013 Draft) (PDF) (71pp, 1.6 MB) Source-Oriented Sulfur Dioxide (SO 2 ) Monitoring Technical Assistance Document (Decembe r 2013 Draft) (PDF) (30pp, 3.1 MB) Comments received on May 2013 draft technical assis tance documents (zip) (33.4 MB) Area Designations and Implementation Strategy February 7, 2013 - EPA issued the final primary NAA QS for SO 2 on June 2, 2010. In early June 2013, after the co nsideration of recommendations from air agencies, E PA intends to designate as "nonattainment" those areas with air q uality monitors that violate the SO 2standard. EPA has also developed an updated strate gy for identifying and addressing unhealthy levels of SO 2 in the rest of the country. This strategy recogniz es that existing SO 2monitors may not adequately characterize air quali ty around many of the largest SO 2sources across the country. Accordingly, the strat egy presents a process and timetable by which state s would characterize air quality in these areas, ei ther through expanded air quality monitoring or air qual ity modeling techniques. Next Steps for Area Designations and Implementation of the Sulfur Dioxide National Ambient Air QualityStandard (PDF) (7pp, 125k) Status of First Round Area Designations

Stakeholder Outreach April 12, 2012 - EPA is seeking additional input fr om states, tribes, and other interested parties to refine the agency's approach for implementing the S O 2 standard. We have set up an outreach process that allows for focused disc ussion of monitoring, modeling and implementation i ssues. This effort will ensure that the agency has the information it needs to protect public health from unhealthy level s of SO 2 in the outdoor air. EPA provided letters to states and tribes to notifythem of these plans. Samples of the state and trib al letters are included below. These letters do notrepresent final agency action. Sample letter to state environmental commissioners (PDF) (3pp, 807k) Sample letter to tribal Leaders (PDF) (2pp, 1.1 MB) EPA is convening three small group meetings with st akeholders to discuss issues associated with implem entation of the SO 2standard.

Schedule for Stakeholder Discussions Session 1: Environmental and Public Health Organization Representatives May 30, 2012, Washington, DC Session 2: State and Tribal Representatives May 31, 2012, Research Triangle Park, NC Session 3: Industry Representatives June 1, 2012, Research Triangle Park, NC For more information about these meetings, please c ontact Carolyn Childers at (919) 541-5604. White Paper- To stimulate discussion at the small group meeti ngs and to promote progress toward a workable appro ach for implementing the 1-hour SO 2standard, EPA developed a white paper that identifies important q uestions about how we could determine whether an ar ea is meeting the SO 2standard and how we might use monitoring, modeling, or a combination of monitorin g and modeling. The current version of the white pa per is included below, along with summary informati on for the stakeholder discussions. This white paper is not a final agency action. Information for Stakeholder Meetings on Implementat ion of the SO 2 NAAQS (PDF) (4pp, 277k) White Paper: Implementation of the 2010 Primary 1-H our SO 2 NAAQS (PDF) (15pp, 462k) Summary of Key Comments from Stakeholder Meetings o n SO2 Implementation June 18, 2012 - High level summaries of key comment s from the stakeholder meetings are provided below. High Level Summary of Meeting with Environmental an d Public Health Organization Representatives, May 3 0, 2012 (PDF) (6pp, 65k) High Level Summary of Meeting with State and Tribal Representatives, May 31, 2012 (PDF) (8pp, 69k) High Level Summary of Meeting with Industry Represe ntatives, June 1, 2012 (PDF) (8pp, 73k) September 22, 2011 - Draft Implementation Guidance for the Primary National Ambient Air Quality Standa rd for Sulfur Dioxide 

# Sulfur Dioxide Implementation | Sulfur Dioxide | US EPA http://www.epa.gov/airquality/sulfurdioxide/imp lement.html

2 of 3 8/31/2015 9:41 AMLast updated on 8/19/2015

Draft Guidance (PDF) (94pp, 1.0 MB) Fact Sheet (PDF) (2pp, 89 kb) Notice of Availability (PDF) (3pp, 160 kb) - Federal Register - Oct 3, 2011 Comment Period Extension to December 2, 2011 (PDF) (3pp, 157k) - Federal Register - Oct 28, 2011 EPA Issues Guidance for Designating Areas for the S ulfur Dioxide Primary National Air Quality Standard March 24, 2011 - The Environmental Protection Agenc y issued guidance on the schedule and process for d esignating areas for the 2010 revised primary sulfu r dioxide (SO 2 ) NAAQS. The document also includes guidance on condu cting air quality modeling to inform SO 2designation decisions. Guidance Memorandum (PDF) (42pp, 12.0 MB) - Updated April 11, 2011 

# Sulfur Dioxide Implementation | Sulfur Dioxide | US EPA http://www.epa.gov/airquality/sulfurdioxide/imp lement.html

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